SAM3X/A Series Datasheet by Microchip Technology

Atmet
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Description
The Atmel | SMART SAM3X/A series is a member of a family of Flash
microcontrollers based on the high performance 32-bit ARM Cortex-M3 RISC
processor. It operates at a maximum speed of 84 MHz and features up to
512 Kbytes of Flash and up to 100 Kbytes of SRAM. The peripheral set includes a
High Speed USB Host and Device port with embedded transceiver, an Ethernet
MAC, 2 CANs, a High Speed MCI for SDIO/SD/MMC, an External Bus Interface
with NAND Flash Controller (NFC), 5 UARTs, 2 TWIs, 4 SPIs, as well as a PWM
timer, three 3-channel general-purpose 32-bit timers, a low-power RTC, a low-
power RTT, 256-bit General Purpose Backup Registers, a 12-bit ADC and a 12-bit
DAC.
The SAM3X/A devices have three software-selectable low-power modes: Sleep,
Wait and Backup. In Sleep mode, the processor is stopped while all other
functions can be kept running. In Wait mode, all clocks and functions are stopped
but some peripherals can be configured to wake up the system based on
predefined conditions. In Backup mode, only the RTC, RTT, and wake-up logic
are running.
The SAM3X/A series is ready for capacitive touch thanks to the QTouch library,
offering an easy way to implement buttons, wheels and sliders.
The SAM3X/A architecture is specifically designed to sustain high-speed data
transfers. It includes a multi-layer bus matrix as well as multiple SRAM banks,
PDC and DMA channels that enable it to run tasks in parallel and maximize data
throughput.
The device operates from 1.62V to 3.6V and is available in 100 and 144-lead
LQFP, 100-ball TFBGA and 144-ball LFBGA packages.
The SAM3X/A devices are particularly well suited for networking applications:
industrial and home/building automation, gateways.
SAM3X / SAM3A Series
Atmel | SMART ARM-based MCU
DATASHEET
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
2
1. Features
Core
̶ARM Cortex-M3 revision 2.0 running at up to 84 MHz
̶Memory Protection Unit (MPU)
̶Thumb-2 instruction set
̶24-bit SysTick Counter
̶Nested Vector Interrupt Controller
Memories
̶256 to 512 Kbytes embedded Flash, 128-bit wide access, memory accelerator, dual bank
̶32 to 100 Kbytes embedded SRAM with dual banks
̶16 Kbytes ROM with embedded bootloader routines (UART, USB) and IAP routines
̶Static Memory Controller (SMC): SRAM, NOR, NAND support. NFC with 4 Kbyte RAM buffer and ECC
System
̶Embedded voltage regulator for single supply operation
̶Power-on-Reset (POR), Brown-out Detector (BOD) and Watchdog for safe reset
̶Quartz or ceramic resonator oscillators: 3 to 20 MHz main and optional low power 32.768 kHz for RTC or device
clock
̶High precision 8/12 MHz factory trimmed internal RC oscillator with 4 MHz default frequency for fast device
startup
̶Slow Clock Internal RC oscillator as permanent clock for device clock in low-power mode
̶One PLL for device clock and one dedicated PLL for USB 2.0 High Speed Mini Host/Device
̶Temperature Sensor
̶Up to 17 peripheral DMA (PDC) channels and 6-channel central DMA plus dedicated DMA for High-Speed USB
Mini Host/Device and Ethernet MAC
Low-power Modes
̶Sleep, Wait and Backup modes, down to 2.5 µA in Backup mode with RTC, RTT, and GPBR
Peripherals
̶USB 2.0 Device/Mini Host: 480 Mbps, 4 Kbyte FIFO, up to 10 bidirectional Endpoints, dedicated DMA
̶Up to 4 USARTs (ISO7816, IrDA®, Flow Control, SPI, Manchester and LIN support) and one UART
̶2 TWI (I2C compatible), up to 6 SPIs, 1 SSC (I2S), 1 HSMCI (SDIO/SD/MMC) with up to 2 slots
̶9-channel 32-bit Timer Counter (TC) for capture, compare and PWM mode, Quadrature Decoder Logic and 2-bit
Gray Up/Down Counter for Stepper Motor
̶Up to 8-channel 16-bit PWM (PWMC) with Complementary Output, Fault Input, 12-bit Dead Time Generator
Counter for Motor Control
̶32-bit low-power Real-time Timer (RTT) and low-power Real-time Clock (RTC) with calendar and alarm features
̶256-bit General Purpose Backup Registers (GPBR)
̶16-channel 12-bit 1 msps ADC with differential input mode and programmable gain stage
̶2-channel 12-bit 1 msps DAC
̶Ethernet MAC 10/100 (EMAC) with dedicated DMA
̶2 CAN Controllers with 8 Mailboxes
̶True Random Number Generator (TRNG)
̶Register Write Protection
I/O
̶Up to 103 I/O lines with external interrupt capability (edge or level sensitivity), debouncing, glitch filtering and on-
die Series Resistor Termination
̶Up to six 32-bit Parallel Input/Outputs (PIO)
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Packages
̶100-lead LQFP – 14 x 14 mm, pitch 0.5 mm
̶100-ball TFBGA – 9 x 9 mm, pitch 0.8 mm
̶144-lead LQFP – 20 x 20 mm, pitch 0.5 mm
̶144-ball LFBGA – 10 x 10 mm, pitch 0.8 mm
1.1 Configuration Summary
The SAM3X/A series devices differ in memory sizes, package and features list. Table 1-1 summarizes the
configurations.
Notes: 1. 4 Kbytes RAM buffer of the NFC which can be used by the core if not used by the NFC
2. One channel is reserved for internal temperature sensor
3. Six TC channels are accessible through PIO
4. Three TC channels are accessible through PIO
5. USART3 in UART mode (RXD3 and TXD3 available)
6. Available only on SAM3X8H in LFBGA217 package, which is mounted on SAM3X-EK evaluation kit for SAM3X and SAM3A
series. The SAM3X8H device is not commercially available.
Table 1-1. Configuration Summary
Feature SAM3X8E SAM3X8C SAM3X4E SAM3X4C SAM3A8C SAM3A4C
Flash 2 x 256 Kbytes 2 x 256 Kbytes 2 x 128 Kbytes 2 x 128 Kbytes 2 x 256 Kbytes 2 x 128 Kbytes
SRAM 64 + 32 Kbytes 64 + 32 Kbytes 32 + 32 Kbytes 32 + 32 Kbytes 64 + 32 Kbytes 32 + 32 Kbytes
NAND Flash
Controller (NFC) Yes – Yes – – –
NFC SRAM(1) 4 Kbytes – 4 Kbytes – – –
Package LQFP144
LFBGA144
LQFP100
TFBGA100
LQFP144
LFBGA144
LQFP100
TFBGA100
LQFP100
TFBGA100
LQFP100
TFBGA100
Number of PIOs 103 63 103 63 63 63
SHDN Pin Yes No Yes No No No
EMAC MII/RMII RMII MII/RMII RMII – –
External Bus
Interface
16-bit data,
8 chip selects,
23-bit address –16-bit data,
8 chip selects,
23-bit address –––
SDRAM Controller(6) ––––––
Central DMA646444
12-bit ADC 16 ch.(2) 16 ch.(2) 16 ch.(2) 16 ch.(2) 16 ch.(2) 16 ch.(2)
12-bit DAC 2 ch. 2 ch. 2 ch. 2 ch. 2 ch. 2 ch.
32-bit Timer 9 ch.(3) 9 ch.(4) 9 ch.(3) 9 ch.(4) 9 ch.(3) 9 ch.(3)
PDC Channels 17 15 17 15 15 15
USART/UART 3/2(5) 3/1 3/2(5) 3/1 3/1 3/1
SPI
1 SPI controller,
4 chip selects +
3 USART with
SPI mode
1 SPI controller,
4 chip selects +
3 USART with
SPI mode
1 SPI controller,
4 chip selects +
3 USART with
SPI mode
1 SPI controller,
4 chip selects +
3 USART with
SPI mode
1 SPI controller,
4 chip selects +
3 USART with
SPI mode
1 SPI controller,
4 chip selects +
3 USART with
SPI mode
HSMCI 1 slot, 8 bits 1 slot, 4 bits 1 slot, 8 bits 1 slot, 4 bits 1 slot, 4 bits 1 slot, 4 bits
uomvaor AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
4
2. SAM3X/A Block Diagram
Figure 2-1. SAM3A4/8C (100 pins) Block Diagram
PLLA
TST
PCK0-PCK2
System Controller
FWUP
XIN
XOUT
NRST
PMC
UPLL
WDT
RTT
XIN32
XOUT32
SUPC
8
GPBR
OSC
PIOA PIOB
PIOC
VDDUTMI
VDDCORE
VDDBU
SM
TDI
TDO/TRACESWO
TMS/SWDIO
TCK/SWCLK
JTAGSEL
I/D S
Voltage
Regulator
VDDIN
VDDOUT
PIO
SPI0
SSC
ADC
SPI0_NPCS0
SPI0_NPCS1
SPI0_NPCS2
SPI0_NPCS3
SPI0_MISO
SPI0_MOSI
SPI0_SPCK
USART2
USART1
USART0
UART
TWI1
TWI0
PWM
Timer Counter 2
Timer Counter 1
Timer Counter 0
TF
TK
TD
RD
RK
RF
PDC
DAC
PDC
PDC
DMA
CANRX0
CANTX0
CANRX1
CANTX1
CAN1
CAN0
HSMCI
SRAM1
32 Kbytes
32 Kbytes
16 Kbytes
ROM
16 Kbytes
SRAM0
64 Kbytes
32 Kbytes
16 Kbytes
Flash
2x256 Kbytes
2x128 Kbytes
2x64 Kbytes
GNDANA
VDDANA
Temp.
Sensor
In-Circuit Emulator
MPU
N
V
I
C
24-bit
SysTick Counter
6-layer AHB Bus Matrix f
max
84MHz
DMA
DMA
DMA
TC[6..8]
TC[3..5]
TC[0..2]
JTAG & Serial Wire
ERASE
DFSDM
DFSDP
DHSDM
DHSDP
UOTGVBOF
UOTGID
VBUS
DATRG
ADVREF
ADTRG
AD[0..14]
DAC0
DAC1
Cortex-M3 Processor
f
max
84 MHz
RC
12/8/4 M
OSC 32K
RC 32K
RTC
RSTC
POR
Low Power
Peripheral
Bridge
Peripheral
DMA
Controller
USB
Mini Host/
Device HS
HS UTMI
Transeiver
DMA FIFO
High Performance
Peripheral
Bridge
PDC
PDC
PDC
PDC
PDC
PDCPDC
DMA
DMA
DMA
DMA
TRNG
CTS2
RTS2
SCK2
TXD2
RXD2
CTS1
RTS1
SCK1
TXD1
RXD1
CTS0
RTS0
SCK0
TXD0
UTXD
URXD
TWD1
TWCK1
TWD0
TWCK0
PWMH[0:3]
PWML[0:7]
PWMFI[0:1]
TIOB[3:5]
TIOA[3:5]
TIOB[0:2]
TIOA[0:2]
TCLK[3:5]TCLK[3:5]
TCLK[0:2]
MCDA[0..3]
MCCK
MCCDA
4-Channel
DMA
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Figure 2-2. SAM3X4/8C (100 pins) Block Diagram
4-Channel
DMA
PLLA
TST
PCK0-PCK2
System Controller
VDDBU
FWUP
XIN
NRST
PMC
UPLL
XOUT
WDT
RTT
OSC 32K
XIN32
XOUT32
SUPC
RSTC
8
GPBR
PIOB
POR
PIOC
RTC
RC 32k
VDDCORE
VDDUTMI
SM
RC
12/8/4 M
ERASE
TDI
TDO/TRACESWO
TMS/SWDIO
TCK/SWCLK
JTAGSEL
I/D S
VDDIN
VDDOUT
PIO
USART1
SPI0
Timer Counter 0
TC[0..2]
ADC
PDC
TIOA[0:2]
TIOB[0:2]
TCLK[0:2]
RXD1
TXD1
SCK1
RTS1
CTS1
USART0
RXD0
TXD0
SCK0
RTS0
CTS0
USART2
PDC
RXD2
TXD2
SCK2
RTS2
CTS2
UART
URXD
UTXD
TWI0
TWCK0
TWD0
PWM
PDC
SSC
TF
TK
TD
RD
RK
RF
DAC
PDC
TRNG
CA N 0
CA NRX 0
CA NTX 0
CA N 1
CA NRX 1
CA NTX 1
HSMCI
Te m p .
Se n s o r
Cortex-M3 Processor
f
max
84 MHz
In-circuit Emulator
MPU
N
V
I
C
24-bit
SysTick Counter
Low Power
Peripheral
Bridge
Peripheral
DMA
Controller
6-layer AHB Bus Matrix f
max
84 MHz
DMA
DMA
DMA
DMA
DMA
DMA
DMA
High Performance
Peripherals
Bridge
Timer Counter 1
TC[3..5]
Timer Counter 2
TC[6..8]
TWI1
TWCK1
TWD1
USB
Mini Host/
Device HS
HS UTMI
Transceiver
FIFO
DFSDM
DFSDP
DHSDM
DHSDP
UOTGVBOF
UOTGID
VBUS
OSC
12M
ROM
16 Kbytes
Flash
2x256 Kbytes
2x128 Kbytes
2x64 Kbytes
SRAM1
32 Kbytes
32 Kbytes
16 Kbytes
64 Kbytes
32 Kbytes
16 Kbytes
SRAM0
Voltage
Regulator
GNDANA
VDDANA
JTAG & Serial Wire
ADVREF
ADTRG
AD[0..14]
DAC0
DAC1
DATRG
SPI0_NPCS3
SPI0_MISO
SPI0_MOSI
SPI0_SPCK
SPI0_NPCS2
SPI0_NPCS1
SPI0_NPCS0
PDC
PDC
PDC
PDC
PDC
PIOA
DMA
Ethernet
MAC
RMII
FIFO
128-byte TX
ETXEN
EMDC
EMDIO
ETX0-ETX1
ERX0-ERX1
EREFCK
ERXER
ECRSDV
PWMH[0:3]
PWML[0:3]
PWMFI[0:1]
MCDA[0..3]
MCCDA
MCCK
DMA
DMA
128-byte RX
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
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Figure 2-3. SAM3X4/8E (144 pins) Block Diagram
6-Channel
DMA
PLLA
TST
PCK0-PCK2
System Controller
VDDBU
FWUP
XIN
NRST
PMC
UPLL
XOUT
WDT
RTT
OSC 32K
XIN32
XOUT32
SUPC
RSTC
8
GPBR
OSC
PIOA PIOB
POR
PIOC
RTC
RC 32K
VDDCORE
VDDUTMI
SM
RC
12/8/4 M
ERASE
TDI
TDO/TRACESWO
TMS/SWDIO
TCK/SWCLK
JTAGSEL
I/D S
Voltage
Regulator
VDDIN
VDDOUT
PIO
SPI0
TC[0..2]
ADC
ADVREF
SPI0_NPCS3
SPI0_MISO
SPI0_MOSI
SPI0_SPCK
TIOA[0:2]
TIOB[0:2]
ADTRG
AD[0..14]
TCLK[0:2]
RXD1
TXD1
SCK1
RTS1
CTS1
USART0
RXD0
TXD0
SCK0
RTS0
CTS0
RXD2
TXD2
SCK2
RTS2
CTS2
UART
TWI0
TWCK0
TWD0
PWM SSC
TF
TK
TD
RD
RK
RF
DAC PDC
DAC0
DAC1
TRNG
CAN0
CAN1
CANTX1
HSMCI
ROM
16 Kbytes
Flash
2x256 Kbytes
2x128 Kbytes
2x64 Kbytes
SRAM1
GNDANA
VDDANA
Temp..
Sensor
Cortex-M3 Processor
f
max
84 MHz
In-circuit Emulator
MPU
N
V
I
C
24-bit
SysTick Counter
Low Power
Peripheral
Bridge
6-layer AHB Bus Matrix f
max
84 MHz
DMA
DMA
High Performance
Peripherals
Bridge
TC[3..5]
Timer Counter 2
TC[6..8]
TWI1
TWCK1
TWD1
JTAG & Serial Wire
USBOTG
Device
HS
HS UTMI
Transceiver
FIFO
DFSDM
DFSDP
DHSDM
DHSDP
UOTGVBOF
UOTGID
VBUS
URXD
UTXD
DATRG
DMA
SPI0_NPCS2
SPI0_NPCS1
SPI0_NPCS0
DMA
DMA
32 Kbytes
32 Kbytes
16 Kbytes
64 Kbytes
32 Kbytes
16 Kbytes
SRAM0
Peripheral
DMA
PDC
PDC
Timer Counter 1
Timer Counter 0
DMA
DMA
DMA
USART1
USART2
CANRX1
CANTX0
CANRX0
PDC
PDC
PDC
PDC
PDC
PDC
RXD3
TXD3
PIO
Static Memory
ECC
Controller
EBI
NAND Flash
D[15:0]
A0/NBS0
A[0:23]
A21/NANDALE
A22/NANDCLE
A16
A17
NCS0
NCS1
NCS2
NCS3
NRD
NWR0/NWE
NWR1
NANDOE
NANDWE
NWAIT
8-bit/16-bit
4 Kbyte FIFO
Ethernet
MAC
MII/RMII
FIFO
128-byte TX
ETXCK-ERXCK-EREFCK
ECRS-ECOL, ECRSDV
ETX0-ETX3
EMDC
EMDIO
EF100
MCDA[0..7]
TIOA[6:8]
TIOB[6:8]
TCLK[6:8]
PWMH[0:6]
PWML[0:7]
PWMFI[0:2]
SHDN
PIOD
PIOE
NRSTB
MCCDA
MCCK
Controller
ERX0-ERX3
ERXER-ERXDV
ETXER-ETXDV
DMA
128-byte RX
Controller
NANDRDY
USART3
PDC
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Figure 2-4. SAM3X8H (217 pins) Block Diagram (not commercially available)
6-Channel
DMA
PLLA
TST
PCK0-PCK2
System Controller
VDDBU
FWUP
XIN
NRST
PMC
UPLL
XOUT
WDT
RTT
OSC 32K
XIN32
XOUT32
SUPC
RSTC
8
GPBR
OSC
PIOB
POR
PIOC
RTC
RC 32k
VDDCORE
VDDUTMI
SM
RC
12/8/4 M
ERASE
TDI
TDO/TRACESWO
TMS/SWDIO
TCK/SWCLK
JTAGSEL
I/D S
Voltage
Regulator
VDDIN
VDDOUT
PIO
SPI0
Timer Counter 0
TC[0..2]
ADC
ADVREF
PDC
TIOA[0:2]
TIOB[0:2]
ADTRG
AD[0..14]
TCLK[0:2]
RXD1
TXD1
SCK1
RTS1
CTS1
USART0
RXD0
TXD0
SCK0
RTS0
CTS0
USART2
PDC
RXD2
TXD2
SCK2
RTS2
CTS2
UART
DRXD
DTXD
TWI0
TWCK0
TWD0
PWM
PDC
SSC
TF
TK
TD
RD
RK
RF
DAC
PDC
DAC0
DAC1
TRNG
CAN0
CAN1
CANRX1
CANTX1
HSMCI
ROM
16 Kbytes
SRAM0
64 Kbytes
32 Kbytes
16 Kbytes
Flash
2x256 Kbytes
2x128 Kbytes
2x64 Kbytes
SRAM1
32 Kbytes
32 Kbytes
16 Kbytes
GNDANA
VDDANA
Temp.
Sensor
Cortex-M3 Processor
f
max
84 MHz
In-Circuit Emulator
MPU
N
V
I
C
24-bit
SysTick Counter
Low Power
Peripheral
Bridge
Peripheral
DMA
Controller
6-layer AHB Bus Matrix f
max
84 MHz
DMA
DMA
High Performance
Peripherals
Bridge
TC[3..5]
Timer Counter 2
TC[6..8]
TWI1
TWCK1
TWD1
JTAG & Serial Wire
HS UTMI
Transceiver
DMA
FIFO
DFSDM
DFSDP
DHSDM
DHSDP
UOTGVBOF
UOTGID
VBUS
PIOA
CANRX0
CANTX0
Timer Counter 1
PDC
PDC
PDC
PDC
PDC
DMA
DMA
DMA
USART1
DMA
DMA
DMA
USB
Mini Host/
Device HS
USB
Mini Host/
Device HS
USB
Mini Host/
Device HS
TIOA[3:5]
TIOB[3:5]
TCLK[3:5]
TIOA[6:8]
TIOB[6:8]
TCLK[6:8]
PWMH[0:7]
PWML[0:7]
PWMFI[0:2]
DMA
Ethernet
MAC
MII/RMII
FIFO
128-byte TX
ETXEN-ETXER
ECRS-ECOL, ECRSDV
ETX0-ETX3
EMDC
EMDIO
EF100
PIO
Static Memory
ECC
SDRAM
Controller
EBI
NAND Flash
D[15:0]
A0/NBS0
A[0:23]
A21/NANDALE
A22/NANDCLE
A16/BA0
A17/BA1
NCS0
NCS1
NCS2
NCS3
NRD
NWR0/NWE
NWR1/NBS1
SDCKE
RAS
CAS
SDWE
SDCS
NCS4
NCS5
NCS6
NCS7
NANDOE
NANDWE
NWAIT
8-bit/16-bit
4 Kbyte FIFO
SPI1
USART3
PDC
RXD3
TXD3
SCK3
RTS3
CTS3
MCCDB
MCDB[0..3]
MCDA[0..7]
PIOD
PIOE PIOF
SHDN
DATRG
NRSTB
128-byte RX
Controller
Controller
MCCDA
MCCK
SPI0_NPCS0
SPI0_NPCS1
SPI0_NPCS2
SPI0_NPCS3
SPI0_MISO
SPI0_MOSI
SPI0_SPCK
SDCK
ERX0-ERX3
ERXER-ERXDV
ETXCK-ERXC
SPI1_NPCS0
SPI1_NPCS1
SPI1_NPCS2
SPI1_NPCS3
SPI1_MISO
SPI1_MOSI
SPI1_SPCK
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
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3. Signal Description
Table 3-1 gives details on the signal names classified by peripheral.
Table 3-1. Signal Description List
Signal Name Function Type Active
Level Voltage
Reference Comments
Power Supplies
VDDIO Peripherals I/O Lines Power Supply Power 1.62V to 3.6V
VDDUTMI USB UTMI+ Interface Power
Supply Power 3.0V to 3.6V
VDDOUT Voltage Regulator Output Power
VDDIN Voltage Regulator, ADC and DAC
Power Supply Power
GNDUTMI USB UTMI+ Interface Ground Ground
VDDBU Backup I/O Lines Power Supply Power 1.62V to 3.6V
GNDBU Backup Ground Ground
VDDPLL PLL A, UPLL and Oscillator Power
Supply Power 1.62 V to 1.95V
GNDPLL PLL A, UPLL and Oscillator Ground Ground
VDDANA ADC and DAC Analog Power
Supply Power 2.0V to 3.6V
GNDANA ADC and DAC Analog Ground Ground
VDDCORE Core Chip Power Supply Power 1.62V to 1.95V
GND Ground Ground
Clocks, Oscillators and PLLs
XIN Main Oscillator Input Input VDDPLL
XOUT Main Oscillator Output Output
XIN32 Slow Clock Oscillator Input Input VDDBU
XOUT32 Slow Clock Oscillator Output Output
VBG Bias Voltage Reference Analog
PCK0–PCK2 Programmable Clock Output Output
Shutdown, Wakeup Logic
SHDN Shut-Down Control Output VDDBU
0: Device is in backup mode
1: Device is running (not in
backup mode)
FWUP Force Wake-up Input Input VDDBU Needs external pull-up
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
ICE and JTAG
TCK/SWCLK Test Clock/Serial Wire Clock Input
VDDIO
Reset State:
- SWJ-DP Mode
- Internal pull-up disabled(1)
TDI Test Data In Input
TDO/TRACESWO Test Data Out / Trace
Asynchronous Data Out Output
TMS/SWDIO Test Mode Select /Serial Wire
Input/Output Input / I/O
JTAGSEL JTAG Selection Input High VDDBU Permanent Internal
pull-down
Flash Memory
ERASE Flash and NVM Configuration Bits
Erase Command Input High VDDIO Pull-down resistor
Reset/Test
NRST Microcontroller Reset I/O Low VDDIO Pull-up resistor
NRSTB Asynchronous Microcontroller
Reset Input Low VDDBU Pull-up resistor
TST Test Mode Select Input VDDBU Pull-down resistor
Universal Asynchronous Receiver Transceiver - UART
URXD UART Receive Data Input
UTXD UART Transmit Data Output
PIO Controller - PIOA - PIOB - PIOC - PIOD - PIOE - PIOF
PA0–PA31 Parallel IO Controller A I/O
VDDIO
Schmitt Trigger(3)
Reset State:
- PIO Input
- Internal pull-up enabled
PB0–PB31 Parallel IO Controller B I/O
Schmitt Trigger(4)
Reset State:
- PIO Input
- Internal pull-up enabled
PC0–PC30 Parallel IO Controller C I/O
Schmitt Trigger(5)
Reset State:
- PIO Input
- Internal pull-up enabled
PD0–PD30 Parallel IO Controller D I/O
Schmitt Trigger(6)
Reset State:
- PIO Input
- Internal pull-up enabled
PE0–PE31 Parallel IO Controller E I/O
Schmitt Trigger(7)
Reset State:
- PIO Input
- Internal pull-up enabled
PF0–PF6 Parallel IO Controller F I/O
Schmitt Trigger(7)
Reset State:
- PIO Input
- Internal pull-up enabled
Table 3-1. Signal Description List (Continued)
Signal Name Function Type Active
Level Voltage
Reference Comments
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External Memory Bus
D0–D15 Data Bus I/O Pulled-up input at reset
A0–A23 Address Bus Output 0 at reset
Static Memory Controller - SMC
NCS0–NCS7 Chip Select Lines Output Low
NWR0–NWR1 Write Signal Output Low
NRD Read Signal Output Low
NWE Write Enable Output Low
NBS0–NBS1 Byte Mask Signal Output Low
NWAIT External Wait Signal Input Low
NAND Flash Controller - NFC
NANDOE NAND Flash Output Enable Output Low
NANDWE NAND Flash Write Enable Output Low
NANDRDY NAND Ready Input
NANDCLE NAND Flash Command Line
Enable Output Low
NANDALE NAND Flash Address Line Enable Output Low
SDRAM Controller - SDRAMC
SDCK SDRAM Clock Output Tied low after reset
SDCKE SDRAM Clock Enable Output High
SDCS SDRAM Controller Chip Select Line Output Low
BA[1:0] Bank Select Output
SDWE SDRAM Write Enable Output Low
RAS - CAS Row and Column Signal Output Low
NBS[1:0] Byte Mask Signals Output Low
SDA10 SDRAM Address 10 Line Output
High Speed Multimedia Card Interface - HSMCI
MCCK Multimedia Card Clock I/O
MCCDA Multimedia Card Slot A Command I/O
MCDA0–MCDA7 Multimedia Card Slot A Data I/O
MCCDB Multimedia Card Slot B Command I/O
MCDB0–MCDB3 Multimedia Card Slot A Data I/O
Universal Synchronous Asynchronous Receiver Transmitter - USARTx
SCKx USARTx Serial Clock I/O
TXDx USARTx Transmit Data I/O
RXDx USARTx Receive Data Input
RTSx USARTx Request To Send Output
CTSx USARTx Clear To Send Input
Table 3-1. Signal Description List (Continued)
Signal Name Function Type Active
Level Voltage
Reference Comments
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Ethernet MAC 10/100 - EMAC
EREFCK Reference Clock Input RMII only
ETXCK Transmit Clock Input MII only
ERXCK Receive Clock Input MII only
ETXEN Transmit Enable Output
ETX0–ETX3 Transmit Data Output ETX0–ETX1
only in RMII
ETXER Transmit Coding Error Output MII only
ERXDV Receive Data Valid Input MII only
ECRSDV Carrier Sense and Data Valid Input RMII only
ERX0–ERX3 Receive Data Input ERX0–ERX1
only in RMII
ERXER Receive Error Input
ECRS Carrier Sense Input MII only
ECOL Collision Detected Input MII only
EMDC Management Data Clock Output
EMDIO Management Data Input/Output I/O
CAN Controller - CANx
CANRXx CAN Input Input
CANTXx CAN Output Output
Synchronous Serial Controller - SSC
TD SSC Transmit Data Output
RD SSC Receive Data Input
TK SSC Transmit Clock I/O
RK SSC Receive Clock I/O
TF SSC Transmit Frame Sync I/O
RF SSC Receive Frame Sync I/O
Timer/Counter - TC
TCLKx TC Channel x External Clock Input Input
TIOAx TC Channel x I/O Line A I/O
TIOBx TC Channel x I/O Line B I/O
Pulse Width Modulation Controller - PWMC
PWMHx PWM Waveform Output High for
channel x Output
PWMLx PWM Waveform Output Low for
channel x Output
Only output in
complementary mode when
dead time insertion is
enabled
PWMFIx PWM Fault Input for channel x Input
Table 3-1. Signal Description List (Continued)
Signal Name Function Type Active
Level Voltage
Reference Comments
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Notes: 1. TDO pin is set in input mode when the Cortex-M3 Core is not in debug mode. Thus the internal pull-up corresponding to this
PIO line must be enabled to avoid current consumption due to floating input.
2. PIOA: Schmitt Trigger on all, except PA0, PA9, PA26, PA29, PA30, PA31
3. PIOB: Schmitt Trigger on all, except PB14 and PB22
Serial Peripheral Interface - SPIx
SPIx_MISO Master In Slave Out I/O
SPIx_MOSI Master Out Slave In I/O
SPIx_SPCK SPI Serial Clock I/O
SPIx_NPCS0 SPI Peripheral Chip Select 0 I/O Low
SPIx_NPCS1–SPIx_NPCS3 SPI Peripheral Chip Select Output Low
Two-Wire Interface - TWIx
TWDx TWIx Two-wire Serial Data I/O
TWCKx TWIx Two-wire Serial Clock I/O
Analog-to-Digital Converter - ADC
AD0–AD14 Analog Inputs Analog
ADTRG ADC Trigger Input
ADVREF ADC and DAC Reference Analog
Digital-to-Analog Converter Controller - DACC
DAC0 DAC channel 0 analog output Analog
DAC1 DAC channel 1 analog output Analog
DATRG DAC Trigger
Fast Flash Programming Interface - FFPI
PGMEN0–PGMEN2 Programming Enabling Input VDDIO
PGMM0–PGMM3 Programming Mode Input VDDIO
PGMD0–PGMD15 Programming Data I/O VDDIO
PGMRDY Programming Ready Output High VDDIO
PGMNVALID Data Direction Output Low VDDIO
PGMNOE Programming Read Input Low VDDIO
PGMCK Programming Clock Input VDDIO
PGMNCMD Programming Command Input Low VDDIO
USB High Speed Device
VBUS USB Bus Power Measurement Mini
Host/Device Analog
DFSDM USB Full Speed Data - Analog VDDUTMI
DFSDP USB Full Speed Data + Analog VDDUTMI
DHSDM USB High Speed Data - Analog VDDUTMI
DHSDP USB High Speed Data + Analog VDDUTMI
UOTGVBOF USB VBus On/Off: Bus Power
Control Port VDDIO
UOTGID USB Identification: Mini Connector
Identification Port VDDIO
Table 3-1. Signal Description List (Continued)
Signal Name Function Type Active
Level Voltage
Reference Comments
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4. PIOC: Schmitt Trigger on all, except PC2 to PC9, PC15 to PC24
5. PIOD: Schmitt Trigger on all, except PD10 to PD30
6. PIOE: Schmitt Trigger on all, except PE0 to PE4, PE15, PE17, PE19, PE21, PE23, PE25, PE29
7. PIOF: Schmitt Trigger on all PIOs
3.1 Design Considerations
To facilitate schematic capture when using a SAM3X/A design, refer to the application note Atmel AT03462:
ATSAM3X and ATSAM3A Series - Checklist (literature No. 42187) available on www.atmel.com.
0000000000 0000000000 oucoooooao 0000000000 0000000000 oaoooooaoo oooooooooo aooaoooooo oooooocooo oooooooooo
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4. Package and Pinout
4.1 SAM3A4/8C and SAM3X4/8C Package and Pinout
The SAM3A4/8C and SAM3X4/8C are available in 100-lead LQFP and 100-ball TFBGA packages.
4.1.1 100-lead LQFP Package Outline
Figure 4-1. Orientation of the 100-lead LQFP Package
4.1.2 100-ball TFBGA Package Outline
Figure 4-2. Orientation of the 100-ball TFBGA Package
51
76
75
50
26
25
1
100
1
3
4
5
6
7
8
9
10
2
ABCDEFGHJK
TOP VIEW
BALL A1
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4.1.3 100-lead LQFP Pinout
Table 4-1. 100-lead LQFP SAM3A4/8C and SAM3X4/8C Pinout
1 P B 2 6 2 6 D H S D P 5 1 V D D A N A 7 6 P A 2 6
2 PA9 27 DHSDM 52 GNDANA 77 PA27
3 PA10 28 VBUS 53 ADVREF 78 PA28
4 PA11 29 VBG 54 PB15 79 PA29
5 PA12 30 VDDUTMI 55 PB16 80 PB0
6 PA13 31 DFSDP 56 PA16 81 PB1
7 PA14 32 DFSDM 57 PA24 82 PB2
8 PA15 33 GNDUTMI 58 PA23 83 PB3
9 PA17 34 VDDCORE 59 PA22 84 PB4
10 VDDCORE 35 JTAGSEL 60 PA6 85 PB5
11 VDDIO 36 XIN32 61 PA4 86 PB6
12 GND 37 XOUT32 62 PA3 87 PB7
13 PA0 38 TST 63 PA2 88 PB8
14 PA1 39 VDDBU 64 PB12 89 VDDCORE
15 PA5 40 FWUP 65 PB13 90 VDDIO
16 PA7 41 GND 66 PB17 91 GND
17 PA8 42 VDDOUT 67 PB18 92 PB9
18 PB28 43 VDDIN 68 PB19 93 PB10
19 PB29 44 GND 69 PB20 94 PB11
20 PB30 45 VDDCORE 70 PB21 95 PC0
21 PB31 46 PB27 71 VDDCORE 96 PB14
22 GNDPLL 47 NRST 72 VDDIO 97 PB22
23 VDDPLL 48 PA18 73 GND 98 PB23
24 XOUT 49 PA19 74 PA21 99 PB24
25 XIN 50 PA20 75 PA25 100 PB25
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4.1.4 100-ball TFBGA Pinout
Table 4-2. 100-ball TFBGA SAM3X4/8E Package and Pinout
A1 PB26 C6 PB11 F1 VDDPLL H6 NRST
A2 PB24 C7 PB8 F2 GNDPLL H7 PA19
A3 PB22 C8 PB4 F3 PB30 H8 PA4
A4 PB14 C9 PB0 F4 PB29 H9 PA6
A5 PC0 C10 PA25 F5 GND H10 PA22
A6 PB9 D1 PA5 F6 GND J1 VBUS
A7 PB6 D2 PA0 F7 VDDIO J2 DHSDP
A8 PB2 D3 PA1 F8 PB13 J3 DHSDM
A9 PA28 D4 VDDCORE F9 PB17 J4 JTAGSEL
A10 PA26 D5 VDDIO F10 PB18 J5 XIN32
B1 PA11 D6 VDDCORE G1 XOUT J6 VDDIN
B2 PB25 D7 VDDCORE G2 VDDUTMI J7 PA23
B3 PB23 D8 PB5 G3 PB31 J8 PA24
B4 PA10 D9 PB1 G4 GNDBU J9 PB16
B5 PA9 D10 PA21 G5 PB27 J10 PA16
B6 PB10 E1 PB28 G6 PA18 K1 VBG
B7 PB7 E2 PA7 G7 PA20 K2 DFSDP
B8 PB3 E3 PA8 G8 PA3 K3 DFSDM
B9 PA29 E4 VDDCORE G9 PA2 K4 VDDCORE
B10 PA27 E5 GND G10 PB12 K5 XOUT32
C1 PA12 E6 GND H1 XIN K6 VDDOUT
C2 PA14 E7 VDDIO H2 GNDUTMI K7 VDDANA
C3 PA13 E8 PB19 H3 TST K8 GNDANA
C4 PA17 E9 PB20 H4 VDDBU K9 ADVREF
C5 PA15 E10 PB21 H5 FWUP K10 PB15
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4.2 SAM3X4/8E Package and Pinout
The SAM3X4/8E is available in 144-lead LQFP and 144-ball LFBGA packages.
4.2.1 144-lead LQFP Package Outline
Figure 4-3. Orientation of the 144-lead LQFP Package
4.2.2 144-ball LFBGA Package Outline
The 144-ball LFBGA package has a 0.8 mm ball pitch and respects Green Standards. Its dimensions are 10 x 10 x
1.4 mm.
Figure 4-4. Orientation of the 144-ball LFBGA Package
73
109
108
72
37
36
1
144
TOP VIEW
BALL A1
12
1
2
3
4
5
6
7
8
9
10
11
ABCDEFGHJ KLM
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4.2.3 144-lead LQFP Pinout
Table 4-3. 144-lead LQFP SAM3X4/8E Pinout
1 PB26 37 DHSDP 73 VDDANA 109 PA26
2 PA9 38 DHSDM 74 GNDANA 110 PA27
3 PA10 39 VBUS 75 ADVREF 111 PA28
4 PA11 40 VBG 76 PB15 112 PA29
5 PA12 41 VDDUTMI 77 PB16 113 PB0
6 PA13 42 DFSDP 78 PA16 114 PB1
7 PA14 43 DFSDM 79 PA24 115 PB2
8 PA15 44 GNDUTMI 80 PA23 116 PC4
9 PA17 45 VDDCORE 81 PA22 117 PC10
10 VDDCORE 46 JTAGSEL 82 PA6 118 PB3
11 VDDIO 47 NRSTB 83 PA4 119 PB4
12 GND 48 XIN32 84 PA3 120 PB5
13 PD0 49 XOUT32 85 PA2 121 PB6
14 PD1 50 SHDN 86 PB12 122 PB7
15 PD2 51 TST 87 PB13 123 PB8
16 PD3 52 VDDBU 88 PB17 124 VDDCORE
17 PD4 53 FWUP 89 PB18 125 VDDIO
18 PD5 54 GNDBU 90 PB19 126 GND
19 PD6 55 PC1 91 PB20 127 PB9
20 PD7 56 VDDOUT 92 PB21 128 PB10
21 PD8 57 VDDIN 93 PC11 129 PB11
22 PD9 58 GND 94 PC12 130 PC0
23 PA0 59 PC2 95 PC13 131 PC20
24 PA1 60 PC3 96 PC14 132 PC21
25 PA5 61 VDDCORE 97 PC15 133 PC22
26 PA7 62 VDDIO 98 PC16 134 PC23
27 PA8 63 PC5 99 PC17 135 PC24
28 PB28 64 PC6 100 PC18 136 PC25
29 PB29 65 PC7 101 PC19 137 PC26
30 PB30 66 PC8 102 PC29 138 PC27
31 PB31 67 PC9 103 PC30 139 PC28
32 PD10 68 PB27 104 VDDCORE 140 PB14
33 GNDPLL 69 NRST 105 VDDIO 141 PB22
34 VDDPLL 70 PA18 106 GND 142 PB23
35 XOUT 71 PA19 107 PA21 143 PB24
36 XIN 72 PA20 108 PA25 144 PB25
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4.2.4 144-ball LFBGA Pinout
Table 4-4. 144-ball LFBGA SAM3X4/8E Pinout
A1 PA9 D1 PA17 G1 PA5 K1 VDDCORE
A2 PB23 D2 PD0 G2 PA7 K2 GNDUTMI
A3 PB14 D3 PA11 G3 PA8 K3 VDDPLL
A4 PC26 D4 PA15 G4 PA1 K4 NRSTB
A5 PC24 D5 PA14 G5 GND K5 SHDN
A6 PC20 D6 PC27 G6 GND K6 PC3
A7 PB10 D7 PC25 G7 GND K7 PC6
A8 PB6 D8 VDDIO G8 PC16 K8 PC7
A9 PB4 D9 PB5 G9 PC15 K9 PA18
A10 PC4 D10 PB0 G10 PC13 K10 PA23
A11 PA28 D11 PC30 G11 PB13 K11 PA16
A12 PA27 D12 PC19 G12 PB18 K12 PA24
B1 PA10 E1 PD1 H1 XOUT L1 DHSDP
B2 PB26 E2 PD2 H2 PB30 L2 DHSDM
B3 PB24 E3 PD3 H3 PB28 L3 VDDUTMI
B4 PC28 E4 PD4 H4 PB29 L4 JTAGSEL
B5 PC23 E5 PD5 H5 VDDBU L5 GNDBU
B6 PC0 E6 VDDCORE H6 VDDCORE L6 PC1
B7 PB9 E7 VDDCORE H7 VDDIO L7 PC2
B8 PB8 E8 VDDCORE H8 PC12 L8 PC5
B9 PB3 E9 PB1 H9 PC11 L9 PC9
B10 PB2 E10 PC18 H10 PA3 L10 PA20
B11 PA26 E11 PB19 H11 PB12 L11 VDDANA
B12 PA25 E12 PB21 H12 PA2 L12 PB16
C1 PA13 F1 PD8 J1 XIN M1 DFSDP
C2 PA12 F2 PD6 J2 GNDPLL M2 DFSDM
C3 PB25 F3 PD9 J3 PD10 M3 VBG
C4 PB22 F4 PA0 J4 PB31 M4 VBUS
C5 PC22 F5 PD7 J5 TST M5 XIN32
C6 PC21 F6 GND J6 FWUP M6 XOUT32
C7 PB11 F7 GND J7 PB27 M7 VDDOUT
C8 PB7 F8 VDDIO J8 NRST M8 VDDIN
C9 PC10 F9 PC17 J9 PA19 M9 PC8
C10 PA29 F10 PC14 J10 PA22 M10 GNDANA
C11 PA21 F11 PB20 J11 PA4 M11 ADVREF
C12 PC29 F12 PB17 J12 PA6 M12 PB15
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5. Power Considerations
5.1 Power Supplies
The SAM3X/A series product has several types of power supply pins:
VDDCORE pins: Power the core, the embedded memories and the peripherals; voltage ranges from 1.62V
to 1.95V.
VDDIO pins: Power the peripherals I/O lines; voltage ranges from 1.62V to 3.6V.
VDDIN pin: Powers the voltage regulator
VDDOUT pin: Output of the voltage regulator
VDDBU pin: Powers the Slow Clock oscillator and a part of the System Controller; voltage ranges from
1.62V to 3.6V. VDDBU must be supplied before or at the same time as VDDIO and VDDCORE.
VDDPLL pin: Powers the PLL A, UPLL and 3–20 MHz Oscillator; voltage ranges from 1.62V to 1.95V.
VDDUTMI pin: Powers the UTMI+ interface; voltage ranges from 3.0V to 3.6V, 3.3V nominal.
VDDANA pin: Powers the ADC and DAC cells; voltage ranges from 2.0V to 3.6V.
Ground pins GND are common to VDDCORE and VDDIO pins power supplies.
Separated ground pins are provided for VDDBU, VDDPLL, VDDUTMI and VDDANA. These ground pins are
respectively GNDBU, GNDPLL, GNDUTMI and GNDANA.
5.2 Power-up Considerations
5.2.1 VDDIO Versus VDDCORE
VDDIO must always be higher than or equal to VDDCORE.
VDDIO must reach its minimum operating voltage (1.60 V) before VDDCORE has reached VDDCORE(min). The minimum
slope for VDDCORE is defined by (VDDCORE(min) - VT+) / tRST.
If VDDCORE rises at the same time as VDDIO, the VDDIO rising slope must be higher than or equal to 5 V/ms.
If VDDCORE is powered by the internal regulator, all power-up considerations are met.
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Figure 5-1. VDDCORE and VDDIO Constraints at Startup
5.2.2 VDDIO Versus VDDIN
At power-up, VDDIO needs to reach 0.6 V before VDDIN reaches 1.0 V.
VDDIO voltage needs to be equal to or below (VDDIN voltage + 0.5 V).
5.3 Voltage Regulator
The SAM3X/A series embeds a voltage regulator that is managed by the Supply Controller.
This internal regulator is intended to supply the internal core of SAM3X/A series but can be used to supply other
parts in the application. It features two different operating modes:
In Normal mode, the voltage regulator consumes less than 700 µA static current and draws 150 mA of
output current. Internal adaptive biasing adjusts the regulator quiescent current depending on the required
load current. In Wait Mode or when the output current is low, quiescent current is only 7 µA.
In Shutdown mode, the voltage regulator consumes less than 1 µA while its output is driven internally to
GND. The default output voltage is 1.80V and the startup time to reach Normal mode is inferior to 400 µs.
For adequate input and output power supply decoupling/bypassing, refer to Table 45-3 ”1.8V Voltage Regulator
Characteristics”.
Supply (V)
Time (t)
t
RST
VDDIO
VT+
VDDCORE
VDDIO(min)
VDDCORE(min)
Core supply POR output
SLCK
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5.4 Typical Powering Schematics
The SAM3X/A series supports a 1.62–3.6 V single supply mode. The internal regulator input connected to the
source and its output feeds VDDCORE. Figure 5-2 shows the power schematics.
Figure 5-2. Single Supply
Note: Restrictions
For USB, VDDUTMI needs to be greater than 3.0V.
For ADC, VDDANA needs to be greater than 2.0V.
For DAC, VDDANA needs to be greater than 2.4V.
VDDIN
Voltage
Regulator
VDDOUT
Main Supply (1.62–3.6 V)
VDDCORE
VDDBU
VDDUTMI
VDDIO
VDDANA
VDDPLL
‘ ““ m “““ m ““““ m “““ m ““““ m ““““ m ““““ nan; Tr
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Figure 5-3. Core Externally Supplied
Note: Restrictions
For USB, VDDUTMI needs to be greater than 3.0V.
For ADC, VDDANA needs to be greater than 2.0V.
For DAC, VDDANA needs to be greater than 2.4V.
VDDIN
Voltage
Regulator
VDDOUT
Main Supply (1.62–3.6 V)
VDDCORE
VDDCORE Supply (1.62–1.95 V)
VDDBU
VDDIO
VDDANA
VDDUTMI
VDDPLL
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Figure 5-4. Backup Batteries Used
Note: 1. Restrictions
For USB, VDDUTMI needs to be greater than 3.0V.
For ADC, VDDANA needs to be greater than 2.0V.
For DAC, VDDANA needs to be greater than 2.4V.
2. VDDUTMI and VDDANA cannot be left unpowered.
VDDIN
Voltage
Regulator
VDDOUT
Main Supply (1.62–3.6 V)
VDDCORE
Backup Batteries VDDBU
VDDIO
VDDANA
VDDUTMI
VDDPLL
FWUP
SHDN
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5.5 Active Mode
Active mode is the normal running mode with the core clock running from the fast RC oscillator, the main crystal
oscillator or the PLLA. The power management controller can be used to adapt the frequency and to disable the
peripheral clocks.
5.6 Low Power Modes
The SAM3X/A devices provide the following low-power modes: Backup, Wait, and Sleep.
5.6.1 Backup Mode
The purpose of backup mode is to achieve the lowest power consumption possible in a system which is performing
periodic wake-ups to perform tasks but not requiring fast startup time (< 0.5 ms).
The Supply Controller, zero-power power-on reset, RTT, RTC, backup registers and 32 kHz oscillator (RC or
crystal oscillator selected by software in the Supply Controller) are running. The regulator and the core supply are
off.
Backup mode is based on the Cortex-M3 deep-sleep mode with the voltage regulator disabled.
The SAM3X/A series can be awakened from this mode through the Force Wake-up pin (FWUP), and Wake-up
input pins WKUP0–15, Supply Monitor, RTT or RTC wake-up event. Current consumption is 2.5 µA typical on
VDDBU.
Backup mode can be entered by using the WFE instruction.
The procedure to enter Backup mode using the WFE instruction is the following:
1. Write a 1 to the SLEEPDEEP bit in the Cortex-M3 processor System Control Register (SCR) (refer to
Section 10.21.7 “System Control Register”).
2. Execute the WFE instruction of the processor.
Exit from Backup mode happens if one of the following enable wake-up events occurs:
Low level, configurable debouncing on FWUP pin
Level transition, configurable debouncing on pins WKUPEN0–15
SM alarm
RTC alarm
RTT alarm
5.6.2 Wait Mode
The purpose of the wait mode is to achieve very low power consumption while maintaining the whole device in a
powered state for a startup time of less than 10 µs.
In this mode, the clocks of the core, peripherals and memories are stopped. However, the core, peripherals and
memories power supplies are still powered. From this mode, a fast start up is available.
This mode is entered via Wait for Event (WFE) instructions with LPM = 1 (Low Power Mode bit in PMC_FSMR).
The Cortex-M3 is able to handle external events or internal events in order to wake-up the core (WFE). This is
done by configuring the external lines WKUP0–15 as fast startup wake-up pins (refer to Section 5.8 “Fast
Startup”). RTC or RTT Alarm and USB wake-up events can be used to wake up the CPU (exit from WFE).
Current consumption in Wait mode is typically 23 µA for total current consumption if the internal voltage regulator
is used or 15 µA if an external regulator is used.
The procedure to enter Wait mode is the following:
1. Select the 4/8/12 MHz Fast RC Oscillator as Main Clock.
2. Set the LPM bit in the PMC Fast Startup Mode Register (PMC_FSMR).
3. Execute the WFE instruction of the processor.
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Note: Internal Main clock resynchronization cycles are necessary between the writing of MOSCRCEN bit and the effective
entry in Wait mode. Depending on the user application, Waiting for MOSCRCEN bit to be cleared is recommended to
ensure that the core will not execute undesired instructions.
5.6.3 Sleep Mode
The purpose of sleep mode is to optimize power consumption of the device versus response time. In this mode,
only the core clock is stopped. The peripheral clocks can be enabled.
This mode is entered via Wait for Interrupt (WFI) or WFE instructions with LPM = 0 in PMC_FSMR.
The processor can be awakened from an interrupt if WFI instruction of the Cortex-M3 is used, or from an event if
the WFE instruction is used to enter this mode.
5.6.4 Low Power Mode Summary Table
The modes detailed above are the main low power modes. Each part can be set to on or off separately and wake-
up sources can be individually configured. Table 5-1 shows a summary of the configurations of the low power
modes.
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Notes: 1. SUPC, 32 kHz Oscillator, RTC, RTT, GPBR, POR.
2. The external loads on PIOs are not taken into account in the calculation.
3. BOD current consumption is not included.
4. When considering the wake-up time, the time required to start the PLL is not taken into account. Once started, the device works with the 4/8/12 MHz Fast
RC oscillator. The user has to add the PLL startup time if it is needed in the system. The wake-up time is defined as the time taken for wake-up until the first
instruction is fetched.
5. Current consumption on VDDBU.
6. 18.4 µA on VDDCORE, 26.6 µA for total current consumption (using internal voltage regulator).
7. Depends on MCK frequency. In this mode, the core is supplied and not clocked but some peripherals can be clocked.
Table 5-1. Low Power Mode Configuration Summary
Mode
VDDBU
Region
(1) Regulator
Core
Memory
Peripherals Mode Entry Potential Wake-up Sources Core at
Wake-up PIO State While in
Low Power Mode PIO State
at Wake-up Consumption(2) (3) Wake-up
Time(4)
Backup Mode ON OFF
SHDN = 0
OFF
(not powered)
WFE
+ SLEEPDEEP = 1
FWUP pin
Pins WKUP0–15
BOD alarm
RTC alarm
RTT alarm
Reset Previous state saved
PIOA &
PIOB &
PIOC &
PIOD &
PIOE &
PIOF
Inputs with pull-ups
2.5 µA typ(5) < 0.5 ms
Wait Mode ON ON
SHDN = 1
Powered
(not clocked)
WFE
+ SLEEPDEEP = 0
+ LPM = 1
Any event from Fast Startup:
- through pins WKUP0–15
- RTC alarm
- RTT alarm
- USB wake-up
Clocked back Previous state saved Unchanged 18.4 µA/26.6 µA(6) < 10 µs
Sleep Mode ON ON
SHDN = 1
Powered(7)
(not clocked)
WFE or WFI
+ SLEEPDEEP = 0
+ LPM = 0
Entry mode = WFI
interrupt only
Entry mode = WFE
Any enabled interrupt
and/or
any event from Fast Startup:
- through pins WKUP0–15
- RTC alarm
- RTT alarm
- USB wake-up
Clocked back Previous state saved Unchanged (7) (7)
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5.7 Wake-up Sources
The wake-up events allow the device to exit the backup mode. When a wake-up event is detected, the Supply
Controller performs a sequence which automatically reenables the core power supply. See Figure 16-7, "Wake Up
Source" on page 277.
5.8 Fast Startup
The SAM3X/A series allows the processor to restart in a few microseconds while the processor is in wait mode. A
fast start up can occur upon detection of a low level on one of the 19 wake-up inputs (WKUP0–15 + RTC + RTT +
USB).
The fast restart circuitry (shown in Figure 28-4, "Fast Startup Circuitry" on page 530) is fully asynchronous and
provides a fast startup signal to the Power Management Controller. As soon as the fast startup signal is asserted,
the PMC automatically restarts the embedded 4/8/12 MHz fast RC oscillator, switches the master clock on this
4 MHz clock by default and reenables the processor clock.
6. Input/Output Lines
The SAM3X/A has different kinds of input/output (I/O) lines, such as general purpose I/Os (GPIO) and system
I/Os. GPIOs can have alternate functions thanks to multiplexing capabilities of the PIO controllers. The same PIO
line can be used whether in IO mode or by the multiplexed peripheral. System I/Os include pins such as test pins,
oscillators, erase or analog inputs.
With a few exceptions, the I/Os have input Schmitt triggers. Refer to the footnotes associated with PIOA to PIOF
on page 12, at the end of Table 3-1 “Signal Description List”.
6.1 General Purpose I/O Lines (GPIO)
GPIO Lines are managed by PIO Controllers. All I/Os have several input or output modes such as pull-up, input
Schmitt triggers, multi-drive (open-drain), glitch filters, debouncing or input change interrupt. Programming of these
modes is performed independently for each I/O line through the PIO controller user interface. For more details,
refer to Section 31. “Parallel Input/Output Controller (PIO)”.
The input output buffers of the PIO lines are supplied through VDDIO power supply rail.
The SAM3X/A embeds high speed pads able to handle up to 65 MHz for HSMCI and SPI clock lines and 45 MHz
on other lines. See Section 45.10 “AC Characteristics” for more details. Typical pull-up value is 100 kΩ for all I/Os.
Each I/O line also embeds an ODT (On-Die Termination) (see Figure 6-1). ODT consists of an internal series
resistor termination scheme for impedance matching between the driver output (SAM3) and the PCB track
impedance preventing signal reflection. The series resistor helps to reduce IOs switching current (di/dt) thereby
reducing in turn, EMI. It also decreases overshoot and undershoot (ringing) due to inductance of interconnect
between devices or between boards. In conclusion, ODT helps reducing signal integrity issues.
Figure 6-1. On-Die Termination
PCB Track
Z0 ~ 50 Ω
Receiver
SAM3 Driver with
R
ODT
Z
O
~ 10 Ω
Z0 ~ Z
O
+ R
ODT
ODT
36 Ω Typ.
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6.2 System I/O Lines
Table 6-1 lists the SAM3X/A system I/O lines shared with PIO lines. These pins are software configurable as
general purpose I/O or system pins. At startup, the default function of these pins is always used.
Notes: 1. If PC0 is used as PIO input in user applications, a low level must be ensured at startup to prevent Flash erase before the
user application sets PC0 into PIO mode.
6.2.1 Serial Wire JTAG Debug Port (SWJ-DP) Pins
The SWJ-DP pins are TCK/SWCLK, TMS/SWDIO, TDO/TRACESWO, TDI and commonly provided on a standard
20-pin JTAG connector defined by ARM. For more details about voltage reference and reset state, refer to Table
3-1 “Signal Description List”.
At startup, SWJ-DP pins are configured in SWJ-DP mode to allow connection with debugging probe. Please refer
to Section 11. “Debug and Test Features”.
SWJ-DP pins can be used as standard I/Os to provide users with more general input/output pins when the debug
port is not needed in the end application. Mode selection between SWJ-DP mode (System IO mode) and general
IO mode is performed through the AHB Matrix Special Function Registers (MATRIX_SFR). Configuration of the
pad for pull-up, triggers, debouncing and glitch filters is possible regardless of the mode.
The JTAGSEL pin is used to select the JTAG boundary scan when asserted at a high level. It integrates a
permanent pull-down resistor of about 15 kΩ to GND, so that it can be left unconnected for normal operations.
By default, the JTAG Debug Port is active. If the debugger host wants to switch to the Serial Wire Debug Port, it
must provide a dedicated JTAG sequence on TMS/SWDIO and TCK/SWCLK which disables the JTAG-DP and
enables the SW-DP. When the Serial Wire Debug Port is active, TDO/TRACESWO can be used for trace.
The asynchronous TRACE output (TRACESWO) is multiplexed with TDO. So the asynchronous trace can only be
used with SW-DP, not JTAG-DP. For more information about SW-DP and JTAG-DP switching, please refer to
Section 11. “Debug and Test Features”.
All JTAG signals are supplied with VDDIO except JTAGSEL, supplied by VDDBU.
6.3 Test Pin
The TST pin is used for JTAG Boundary Scan Manufacturing Test or Fast Flash programming mode of the
SAM3X/A series. The TST pin integrates a permanent pull-down resistor of about 15 kΩ to GND, so that it can be
left unconnected for normal operations. To enter fast programming mode, see Section 19. “Fast Flash
Programming Interface (FFPI)”. For more information on the manufacturing and test mode, refer to Section 11.
“Debug and Test Features”.
Table 6-1. System I/O Configuration Pin List
CCFG_SYSIO
Bit No. Peripheral Default Function
After Reset Other
Function Constraints for
Normal Start Configuration
12 – ERASE PC0 Low Level at startup(1) In Matrix User Interface Registers (refer to
System I/O Configuration Register in
Section 21. “Bus Matrix (MATRIX)”)
– A TCK/SWCLK PB28 –
In PIO Controller
– A TDI PB29 –
– A TDO/TRACESWO PB30 –
– A TMS/SWDIO PB31 –
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6.4 NRST Pin
The NRST pin is bidirectional. It is handled by the on-chip reset controller and can be driven low to provide a reset
signal to the external components, or asserted low externally to reset the microcontroller. It will reset the Core and
the peripherals except the Backup region (RTC, RTT and Supply Controller). There is no constraint on the length
of the reset pulse, and the reset controller can guarantee a minimum pulse length.
The NRST pin integrates a permanent pull-up resistor to VDDIO of about 100 kΩ.
6.5 NRSTB Pin
The NRSTB pin is input only and enables asynchronous reset of the SAM3X/A series when asserted low. The
NRSTB pin integrates a permanent pull-up resistor of about 15 kΩ. This allows connection of a simple push button
on the NRSTB pin as a system-user reset. In all modes, this pin will reset the chip including the Backup region
(RTC, RTT and Supply Controller). It reacts as the Power-on reset. It can be used as an external system reset
source. In harsh environments, it is recommended to add an external capacitor (10 nF) between NRSTB and
VDDBU. (For filtering values, refer to “I/O Characteristics” in Section 45. “Electrical Characteristics”.)
It embeds an anti-glitch filter.
6.6 ERASE Pin
The ERASE pin is used to reinitialize the Flash content (and some of its NVM bits) to an erased state (all bits read
as logic level 1). The ERASE pin and the ROM code ensure an in-situ reprogrammability of the Flash content
without the use of a debug tool. When the security bit is activated, the ERASE pin provides the capability to
reprogram the Flash content. It integrates a pull-down resistor of about 100 kΩ to GND, so that it can be left
unconnected for normal operations.
This pin is debounced by SCLK to improve the glitch tolerance. When the ERASE pin is tied high during less than
100 ms, it is not taken into account. The pin must be tied high during more than 220 ms to perform a Flash erase
operation.
The ERASE pin is a system I/O pin and can be used as a standard I/O. At startup, the ERASE pin is not configured
as a PIO pin. If the ERASE pin is used as a standard I/O, the startup level of this pin must be low to prevent
unwanted erasing. Please refer to Section 9.3 “Peripheral Signal Multiplexing on I/O Lines”. Also, if the ERASE pin
is used as a standard I/O output, asserting the pin to high does not erase the Flash.
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7. Memories
7.1 Product Mapping
Figure 7-1. SAM3X/A Product Mapping
Address memory space
Code
0x00000000
SRAM
0x20000000
Peripherals
0x40000000
External SRAM
0x60000000
Reserved
0xA0000000
System
0xE0000000
0xFFFFFFFF
Code
Internal Flash 1
Boot Memory
0x00000000
Internal Flash 0
0x00080000
HALF_FLASHSIZE
Internal ROM
0x00100000
Reserved
0x00200000
0x1FFFFFFF
SRAM
SRAM0
0x20000000
SRAM1
0x20080000
NFC (SRAM)
0x20100000
UOTGHS (DMA)
0x20180000
Undefined (Abort)
0x20200000
0x40000000
External SRAM
CS0
0x60000000
CS1
0x61000000
CS2
0x62000000
CS3
0x63000000
CS4
0x64000000
CS5
0x65000000
CS6
CS7
0x66000000
0x67000000
NFC
0x68000000
Reserved
0x69000000
CS SDRAMC
0x70000000
Reserved
0x80000000
0x9FFFFFFF
HALF_FLASHSIZE address:
- 512 KB products: 0x000C0000
- 256 KB products: 0x000A0000
- 128 KB products: 0x00090000
Peripherals
HSMCI
21
0x40000000
SSC
26
0x40004000
SPI0
0x40008000
SPI1
0x4000C000
TC0 TC0
0x40080000
27
TC0 TC1
+0x40
28
TC0 TC2
+0x80
29
TC1 TC3
0x40084000
TC1 TC4
+0x40
TC1 TC5
+0x80
TC2 TC6
0x40088000
TC2 TC7
+0x40
TC2 TC8
+0x80
TWI0
22
0x4008C000
TWI1
23
0x40090000
PWM
0x40094000
17
0x40098000
18
0x4009C000
19
0x400A0000
USART3
20
0x400A4000
Reserved
0x400A8000
UOTGHS
0x400AC000
0x400B0000
CAN0
0x400B4000
CAN1
0x400B8000
TRNG
0x400BC000
ADC
0x400C0000
DMAC
0x400C4000
DACC
0x400C8000
Reserved
0x400D0000
System controller
0x400E0000
0x400E2600
0x60000000
System controller
SMC
0x400E0000
SDRAM
0x400E0200
MATRIX
0x400E0400
PMC
5
0x400E0600
UART
0x400E0800
CHIPID
0x400E0940
EEFC0
0x400E0A00
EEFC1
0x400E0C00
PIOA
11
0x400E0E00
PIOB
12
0x400E1000
PIOC
13
0x400E1200
PIOD
0x400E1400
PIOE
0x400E1600
PIOF
0x400E1800
RSTC
0x400E1A00
SUPC
0x400E1A10
RTT
0x400E1A30
WDT
0x400E1A50
RTC
0x400E1A60
GPBR
0x400E1A90
0x400E1AB0
0x4007FFFF
EMAC
USART2
USART1
USART0
9
10
8
6
7
14
15
16
1
3
4
2
24
25
30
31
32
33
34
35
36
40
42
43
44
41
37
39
38
Reserved
Reserved
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7.2 Embedded Memories
7.2.1 Internal SRAM
Table 7-1 shows the embedded high-speed SRAM for the various devices.
Note: 1. This device is not commercially available. Mounted only on the SAM3X-EK evaluation kit.
SRAM0 is accessible over the system Cortex-M3 bus at address 0x2000 0000 and SRAM1 at address 0x2008
0000. The user can see the SRAM as contiguous thanks to mirror effect, giving 0x2007 0000 - 0x2008 7FFF for
SAM3X/A8, and 0x2007 8000 - 0x2008 7FFF for SAM3X/A4.
SRAM0 and SRAM1 are in the bit band region. The bit band alias region is mapped from 0x2200 0000 to
0x23FF FFFF.
The NAND Flash Controller (NFC) embeds 4224 bytes of internal SRAM. If the NFC is not used, these
4224 Kbytes can be used as general-purpose SRAM. It can be seen at address 0x2010 0000.
7.2.2 Internal ROM
The SAM3X/A series product embeds an Internal ROM, which contains the SAM-BA and FFPI program.
At any time, the ROM is mapped at address 0x0010 0000.
7.2.3 Embedded Flash
7.2.3.1 Flash Overview
Table 7-2 shows the Flash organization for the various devices.
The Flash contains a 128-byte write buffer, accessible through a 32-bit interface.
7.2.3.2 Flash Power Supply
The Flash is supplied by VDDCORE.
Table 7-1. Embedded High-speed SRAM per Device
Device Pin Count SRAM0 (KB) SRAM1 (KB) NFC SRAM (KB) Total SRAM (KB)
SAM3X8E 144 64 32 4 100
SAM3X8H(1)
SAM3A8C 100 64 32 – 96
SAM3X8C
SAM3X4E 144 32 32 4 68
SAM3A4C 100 32 32 – 64
SAM3X4C
Table 7-2. Embedded Flash Memory Organization per Device
Device Flash Size (Kbytes) Number of Banks Number of Pages Page Size (bytes) Plane
SAM3A8 512 2 1024 256 Dual
SAM3X8 512 2 1024 256 Dual
SAM3A4 256 2 512 256 Dual
SAM3X4 256 2 512 256 Dual
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7.2.3.3 Enhanced Embedded Flash Controller
The Enhanced Embedded Flash Controller (EEFC) manages accesses performed by the masters of the system. It
enables reading the Flash and writing the write buffer. It also contains a User Interface, mapped within the Memory
Controller on the APB.
The EEFC ensures the interface of the Flash block with the 32-bit internal bus. Its 128-bit wide memory interface
increases performance.
The user can choose between high performance or lower current consumption by selecting either 128-bit or 64-bit
access. It also manages the programming, erasing, locking and unlocking sequences of the Flash using a full set
of commands.
One of the commands returns the embedded Flash descriptor definition that informs the system about the Flash
organization, thus making the software generic.
7.2.3.4 Lock Regions
Several lock bits are used to protect write and erase operations on lock regions. A lock region is composed of
several consecutive pages, and each lock region has its associated lock bit.
If a locked-region’s erase or program command occurs, the command is aborted and the EEFC triggers an
interrupt.
The lock bits are software programmable through the EEFC User Interface. The “Set Lock Bit” command enables
the protection. The “Clear Lock Bit” command unlocks the lock region.
Asserting the ERASE pin clears the lock bits, thus unlocking the entire Flash.
7.2.3.5 Security Bit Feature
The SAM3X/A series features a security bit, based on a specific General Purpose NVM bit (GPNVM bit 0). When
the security is enabled, any access to the Flash, either through the ICE interface or through the Fast Flash
Programming Interface (FFPI), is forbidden. This ensures the confidentiality of the code programmed in the Flash.
This security bit can only be enabled through the “Set General Purpose NVM Bit 0” command of the EEFC0 User
Interface. Disabling the security bit can only be achieved by asserting the ERASE pin at 1, and after a full Flash
erase is performed. When the security bit is deactivated, all accesses to the Flash are permitted.
It is important to note that the assertion of the ERASE pin should always be longer than 200 ms.
As the ERASE pin integrates a permanent pull-down, it can be left unconnected during normal operation.
However, it is safer to connect it directly to GND for the final application.
7.2.3.6 Calibration Bits
NVM bits are used to calibrate the brownout detector and the voltage regulator. These bits are factory configured
and cannot be changed by the user. The ERASE pin has no effect on the calibration bits.
7.2.3.7 Unique Identifier
Each device integrates its own 128-bit unique identifier. These bits are factory configured and cannot be changed
by the user. The ERASE pin has no effect on the unique identifier.
Table 7-3. Number of Lock Bits
Product Number of Lock Bits Lock Region Size
SAM3X8 32 16 Kbytes (64 pages)
SAM3A8
SAM3X4 16 16 Kbytes (64 pages)
SAM3A4
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7.2.3.8 Fast Flash Programming Interface (FFPI)
The FFPI allows device programming through multiplexed fully-handshaked parallel port. It allows gang
programming with market-standard industrial programmers.
The FFPI supports read, page program, page erase, full erase, lock, unlock and protect commands.
The FFPI is enabled and the Fast Programming Mode is entered when TST, PA0, PA1 are set to high, PA2 and
PA3 are set to low and NRST is toggled from 0 to 1.
The table below shows the signal assignment of the PIO lines in FFPI mode
7.2.3.9 SAM-BA Boot
The SAM-BA Boot is a default boot program which provides an easy way to program in-situ the on-chip Flash
memory.
The SAM-BA Boot Assistant supports serial communication via the UART and USB.
The SAM-BA Boot provides an interface with SAM-BA Graphic User Interface (GUI).
The SAM-BA Boot is in ROM and is mapped in Flash at address 0x0 when GPNVM bit 1 is set to 0.
Table 7-4. FFPI PIO Assignment
FFPI Signal PIO Used
PGMNCMD PA0
PGMRDY PA1
PGMNOE PA2
PGMNVALID PA3
PGMM[0] PA4
PGMM[1] PA5
PGMM[2] PA6
PGMM[3] PA7
PGMD[0] PA8
PGMD[1] PA9
PGMD[2] PA10
PGMD[3] PA11
PGMD[4] PA12
PGMD[5] PA13
PGMD[6] PA14
PGMD[7] PA15
PGMD[8] PA16
PGMD[9] PA17
PGMD[10] PA18
PGMD[11] PA19
PGMD[12] PA20
PGMD[13] PA21
PGMD[14] PA22
PGMD[15] PA23
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7.2.3.10 GPNVM Bits
The SAM3X/A series features three GPNVM bits that can be cleared or set respectively through the “Clear
GPNVM Bit” and “Set GPNVM Bit” commands of the EEFC0 User Interface.
There is no GPNVM bit on Flash 1.
The GPNVM0 is the security bit.
The GPNVM1 is used to select the boot mode (boot always at 0x00) on ROM or Flash.
The GPNVM2 is used only to swap the Flash 0 and Flash 1. If GPNVM2 is ENABLE, the Flash 1 is mapped at
address 0x0008_0000 (Flash 1 and Flash 0 are continuous). If GPNVM2 is DISABLE, the Flash 0 is mapped at
address 0x0008_0000 (Flash 0 and Flash 1 are continuous).
7.2.4 Boot Strategies
The system always boots at address 0x0. To ensure maximum boot possibilities, the memory layout can be
changed via GPNVM.
A general-purpose NVM (GPNVM1) bit is used to boot either on the ROM (default) or from the Flash.
Setting GPNVM bit 1 selects the boot from the Flash, clearing it selects the boot from the ROM. Asserting ERASE
clears GPNVM bit 1 and thus selects the boot from the ROM by default.
GPNVM2 enables to select if Flash 0 or Flash 1 is used for the boot.
Setting GPNVM bit 2 selects the boot from Flash 1, clearing it selects the boot from Flash 0.
7.3 External Memories
The 144-pin SAM3X and 217-pin SAM3X8H(1) feature one External Memory Bus to offer interface to a wide range
of external memories and to any parallel peripheral.
Note: 1. This device is not commercially available. Mounted only on the SAM3X-EK evaluation kit.
7.3.1 External Memory Bus
Integrates Four External Memory Controllers:
̶Static Memory Controller
̶NAND Flash Controller
̶SLC NAND Flash ECC Controller
̶Single Data Rate Synchronous Dynamic Random Access Memory (SDR-SDRAM)
Up to 24-bit Address Bus (up to 16 Mbytes linear per chip select)
Up to 8 chip selects, Configurable Assignment
7.3.2 Static Memory Controller
8- or 16-bit Data Bus
Multiple Access Modes supported
̶Byte Write or Byte Select Lines
̶Asynchronous read in Page Mode supported (4- up to 32-byte page size)
Table 7-5. General Purpose Non-volatile Memory Bits
GPNVM Bit[#] Function
0 Security bit
1 Boot mode selection
2 Flash selection (Flash 0 or Flash 1)
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Multiple device adaptability
̶Control signals programmable setup, pulse and hold time for each Memory Bank
Multiple Wait State Management
̶Programmable Wait State Generation
̶External Wait Request
̶Programmable Data Float Time
Slow Clock mode supported
7.3.3 NAND Flash Controller
Handles automatic Read/write transfer through 4224 bytes SRAM buffer
DMA support
Supports SLC NAND Flash technology
Programmable timing on a per chip select basis
Programmable Flash Data width 8-bit or 16-bit
7.3.4 NAND Flash Error Corrected Code Controller
Integrated in the NAND Flash Controller
Single bit error correction and 2-bit Random detection.
Automatic Hamming Code Calculation while writing
̶ECC value available in a register
Automatic Hamming Code Calculation while reading
̶Error Report, including error flag, correctable error flag and word address being detected erroneous
̶Support 8- or 16-bit NAND Flash devices with 512-, 1024-, 2048- or 4096-byte pages
7.3.5 SDR-SDRAM Controller (217-pin SAM3X8H(l) only)
Numerous configurations supported
̶2K, 4K, 8K Row Address Memory Parts
̶SDRAM with two or four Internal Banks
̶SDRAM with 16-bit Data Path
Programming facilities
̶Word, half-word, byte access
̶Automatic page break when Memory Boundary has been reached
̶Multibank Ping-pong Access
̶Timing parameters specified by software
̶Automatic refresh operation, refresh rate is programmable
Energy-saving capabilities
̶Self-refresh, and Low-power Modes supported
Error detection
̶Refresh Error Interrupt
SDRAM Power-up Initialization by software
Latency is set to two clocks (CAS Latency of 1, 3 Not Supported)
Auto Precharge Command not used
Mobile SDRAM supported (except for low-power extended mode and deep power-down mode)
Note: 1. This device is not commercially available. Mounted only on the SAM3X-EK evaluation kit.
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8. System Controller
The System Controller is a set of peripherals which allow handling of key elements of the system such as but not
limited to power, resets, clocks, time, interrupts, and watchdog.
The System Controller User Interface also embeds the registers allowing to configure the Matrix and a set of
registers configuring the SDR-SDRAM chip select assignment.
8.1 System Controller and Peripherals Mapping
Please refer to Figure 7-1 “SAM3X/A Product Mapping” on page 31 .
All the peripherals are in the bit band region and are mapped in the bit band alias region.
8.2 Power-on-Reset, Brownout and Supply Monitor
The SAM3X/A embeds three features to monitor, warn and/or reset the chip:
Power-on-Reset on VDDBU
Brownout Detector on VDDCORE
Supply Monitor on VDDUTMI
8.2.1 Power-on-Reset on VDDBU
The Power-on-Reset monitors VDDBU. It is always activated and monitors voltage at start up but also during
power down. If VDDBU goes below the threshold voltage, the entire chip is reset. For more information, refer to
Section 45. “Electrical Characteristics”.
8.2.2 Brownout Detector on VDDCORE
The Brownout Detector monitors VDDCORE. It is active by default. It can be deactivated by software through the
Supply Controller (SUPC_MR). It is especially recommended to disable it during low-power modes such as wait or
sleep modes.
If VDDCORE goes below the threshold voltage, the reset of the core is asserted. For more information, refer to
Section 16. “Supply Controller (SUPC)” and Section 45. “Electrical Characteristics”.
8.2.3 Supply Monitor on VDDUTMI
The Supply Monitor monitors VDDUTMI. It is not active by default. It can be activated by software and is fully
programmable with 16 steps for the threshold (between 1.9V to 3.4V). It is controlled by the Supply Controller
(SUPC). A sample mode is possible. It allows to divide the supply monitor power consumption by a factor of up to
2048. For more information, refer to Section 16. “Supply Controller (SUPC)” and Section 45. “Electrical
Characteristics”.
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9. Peripherals
9.1 Peripheral Identifiers
Table 9-1 defines the Peripheral Identifiers of the SAM3X/A series. A peripheral identifier is required for the control
of the peripheral interrupt with the Nested Vectored Interrupt Controller and for the control of the peripheral clock
with the Power Management Controller.
Note that some peripherals are always clocked. Please refer to the table below.
Table 9-1. Peripheral Identifiers
Instance
ID Instance Name NVIC
Interrupt PMC
Clock Control Instance Description
0 SUPC X Supply Controller
1 RSTC X Reset Controller
2 RTC X Real-time Clock
3RTTX Real-time Timer
4 WDG X Watchdog Timer
5 PMC X Power Management Controller
6 EEFC0 X Enhanced Embedded Flash Controller 0
7 EEFC1 X Enhanced Embedded Flash Controller 1
8 UART X Universal Asynchronous Receiver Transceiver
9 SMC_SDRAMC X X Static Memory Controller / Synchronous Dynamic RAM Controller
10 SDRAMC X Synchronous Dynamic RAM Controller
11 PIOA X X Parallel I/O Controller A
12 PIOB X X Parallel I/O Controller B
13 PIOC X X Parallel I/O Controller C
14 PIOD X X Parallel I/O Controller D
15 PIOE X X Parallel I/O Controller E
16 PIOF X X Parallel I/O Controller F
17 USART0 X X Universal Synchronous Asynchronous Receiver Transmitter 0
18 USART1 X X Universal Synchronous Asynchronous Receiver Transmitter 1
19 USART2 X X Universal Synchronous Asynchronous Receiver Transmitter 2
20 USART3 X X Universal Synchronous Asynchronous Receiver Transmitter 3
21 HSMCI X X High Speed Multimedia Card Interface
22 TWI0 X X Two-Wire Interface 0
23 TWI1 X X Two-Wire Interface 1
24 SPI0 X X Serial Peripheral Interface 0
25 SPI1 X X Serial Peripheral Interface 1
26 SSC X X Synchronous Serial Controller
27 TC0 X X Timer Counter Channel 0
28 TC1 X X Timer Counter Channel 1
29 TC2 X X Timer Counter Channel 2
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9.2 APB/AHB Bridge
The SAM3X/A series product embeds two separate APB/AHB bridges:
a low speed bridge
a high speed bridge
This architecture enables a concurrent access on both bridges.
SPI, SSC and HSMCI peripherals are on the high-speed bridge connected to DMAC with the internal FIFO for
Channel buffering.
UART, ADC, TWI0–1, USART0–3, PWM, DAC and CAN peripherals are on the low-speed bridge and have
dedicated channels for the Peripheral DMA Channels (PDC). Note that USART0–1 can be used with the DMA as
well.
The peripherals on the high speed bridge are clocked by MCK. On the low-speed bridge, CAN controllers can be
clocked at MCK divided by 2 or 4. Refer to Section 27. “Clock Generator”.
9.3 Peripheral Signal Multiplexing on I/O Lines
The SAM3X/A series product features up to six PIO controllers (PIOA, PIOB, PIOC, PIOD, PIOE, and PIOF) which
multiplex the I/O lines of the peripheral set:
3 PIO controllers on SAM3A and 100-pin SAM3X
4 PIO controllers on 144-pin SAM3X
6 PIO controllers on 217-pin SAM3X8H(1)
Each PIO controller controls up to 32 lines. Each line can be assigned to one of two peripheral functions, A or B.
The multiplexing tables in the following pages define how the I/O lines of the peripherals A and B are multiplexed
on the PIO controllers.
Note that some output-only peripheral functions might be duplicated within the tables.
Note: 1. This device is not commercially available. Mounted only on the SAM3X-EK evaluation kit.
30 TC3 X X Timer Counter Channel 3
31 TC4 X X Timer Counter Channel 4
32 TC5 X X Timer Counter Channel 5
33 TC6 X X Timer Counter Channel 6
34 TC7 X X Timer Counter Channel 7
35 TC8 X X Timer Counter Channel 8
36 PWM X X Pulse Width Modulation Controller
37 ADC X X ADC Controller
38 DACC X X DAC Controller
39 DMAC X X DMA Controller
40 UOTGHS X X USB OTG High Speed
41 TRNG X X True Random Number Generator
42 EMAC X X Ethernet MAC
43 CAN0 X X CAN Controller 0
44 CAN1 X X CAN Controller 1
Table 9-1. Peripheral Identifiers (Continued)
Instance
ID Instance Name NVIC
Interrupt PMC
Clock Control Instance Description
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9.3.1 PIO Controller A Multiplexing
Notes: 1. WKUPx can be used if PIO controller defines the I/O line as "input".
2. To select this extra function, refer to Section 43.5.3 “Analog Inputs”.
3. Analog input has priority over WKUPx pin.
Table 9-2. Multiplexing on PIO Controller A (PIOA)
I/O Line Peripheral A Peripheral B Extra Function Comments
PA0 CANTX0 PWML3
PA1 CANRX0 PCK0 WKUP0(1)
PA2 TIOA1 NANDRDY AD0(2)
PA3 TIOB1 PWMFI1 AD1/WKUP1(3)
PA4 TCLK1 NWAIT AD2(2)
PA5 TIOA2 PWMFI0 WKUP2(1)
PA6 TIOB2 NCS0 AD3(2)
PA7 TCLK2 NCS1 WKUP3(1)
PA8 URXD PWMH0 WKUP4(1)
PA9 UTXD PWMH3
PA10 RXD0 DATRG WKUP5(1)
PA11 TXD0 ADTRG WKUP6(1)
PA12 RXD1 PWML1 WKUP7(1)
PA13 TXD1 PWMH2
PA14 RTS1 TK
PA15 CTS1 TF WKUP8(1)
PA16 SPCK1 TD AD7(2)
PA17 TWD0 SPCK0
PA18 TWCK0 A20 WKUP9(1)
PA19 MCCK PWMH1
PA20 MCCDA PWML2
PA21 MCDA0 PWML0
PA22 MCDA1 TCLK3 AD4(2)
PA23 MCDA2 TCLK4 AD5(2)
PA24 MCDA3 PCK1 AD6(2)
PA25 SPI0_MISO A18
PA26 SPI0_MOSI A19
PA27 SPI0_SPCK A20 WKUP10(1)
PA28 SPI0_NPCS0 PCK2 WKUP11(1)
PA29 SPI0_NPCS1 NRD
PA30 SPI0_NPCS2 PCK1 217 pins
PA31 SPI0_NPCS3 PCK2 217 pins
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9.3.2 PIO Controller B Multiplexing
Notes: 1. SAM3X only
2. SAM3A only
3. To select this extra function, refer to Section 43.5.3 “Analog Inputs”.
4. Analog input has priority over WKUPx pin.
Table 9-3. Multiplexing on PIO Controller B (PIOB)
I/O Line Peripheral A Peripheral B Extra Function Comments
PB0 ETXCK/EREFCK(1) TIOA3(2)
PB1 ETXEN(1) TIOB3(2)
PB2 ETX0(1) TIOA4(2)
PB3 ETX1(1) TIOB4(2)
PB4 ECRSDV/ERXDV(1) TIOA5(2)
PB5 ERX0(1) TIOB5(2)
PB6 ERX1(1) PWML4(2)
PB7 ERXER(1) PWML5(2)
PB8 EMDC(1) PWML6(2)
PB9 EMDIO(1) PWML7(2)
PB10 UOTGVBOF A18
PB11 UOTGID A19
PB12 TWD1 PWMH0 AD8(3)
PB13 TWCK1 PWMH1 AD9(3)
PB14 CANTX1 PWMH2
PB15 CANRX1 PWMH3 DAC0/WKUP12(4)
PB16 TCLK5 PWML0 DAC1(5)
PB17 RF PWML1 AD10(3)
PB18 RD PWML2 AD11(3)
PB19 RK PWML3 AD12(3)
PB20 TXD2 SPI0_NPCS1 AD13(3)
PB21 RXD2 SPI0_NPCS2 AD14/WKUP13(4)
PB22 RTS2 PCK0
PB23 CTS2 SPI0_NPCS3 WKUP14(6)
PB24 SCK2 NCS2
PB25 RTS0 TIOA0
PB26 CTS0 TCLK0 WKUP15(6)
PB27 NCS3 TIOB0
PB28 TCK/SWCLK TCK after reset
PB29 TDI TDI after reset
PB30 TDO/TRACESWO TDO after reset
PB31 TMS/SWDIO TMS after reset
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5. DAC0 is selected when DACC_CHER.CH0 is set. DAC1 is selected when DACC_CHER.CH1 is set. See Section 44.7.3
“DACC Channel Enable Register”.
6. WKUPx can be used if PIO controller defines the I/O line as "input".
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9.3.3 PIO Controller C Multiplexing
Notes: 1. To select this extra function, refer to Section 6.2 “System I/O Lines”.
Table 9-4. Multiplexing on PIO Controller C (PIOC)
I/O Line Peripheral A Peripheral B Extra Function Comments
PC0 ERASE(1)
PC1 144 and 217 pins
PC2 D0 PWML0 144 and 217 pins
PC3 D1 PWMH0 144 and 217 pins
PC4 D2 PWML1 144 and 217 pins
PC5 D3 PWMH1 144 and 217 pins
PC6 D4 PWML2 144 and 217 pins
PC7 D5 PWMH2 144 and 217 pins
PC8 D6 PWML3 144 and 217 pins
PC9 D7 PWMH3 144 and 217 pins
PC10 D8 ECRS 144 and 217 pins
PC11 D9 ERX2 144 and 217 pins
PC12 D10 ERX3 144 and 217 pins
PC13 D11 ECOL 144 and 217 pins
PC14 D12 ERXCK 144 and 217 pins
PC15 D13 ETX2 144 and 217 pins
PC16 D14 ETX3 144 and 217 pins
PC17 D15 ETXER 144 and 217 pins
PC18 NWR0/NWE PWMH6 144 and 217 pins
PC19 NANDOE PWMH5 144 and 217 pins
PC20 NANDWE PWMH4 144 and 217 pins
PC21 A0/NBS0 PWML4 144 and 217 pins
PC22 A1 PWML5 144 and 217 pins
PC23 A2 PWML6 144 and 217 pins
PC24 A3 PWML7 144 and 217 pins
PC25 A4 TIOA6 144 and 217 pins
PC26 A5 TIOB6 144 and 217 pins
PC27 A6 TCLK6 144 and 217 pins
PC28 A7 TIOA7 144 and 217 pins
PC29 A8 TIOB7 144 and 217 pins
PC30 A9 TCLK7 144 and 217 pins
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9.3.4 PIO Controller D Multiplexing
Table 9-5. Multiplexing on PIO Controller D (PIOD)
I/O Line Peripheral A Peripheral B Extra Function Comments
PD0 A10 MCDA4 144 and 217 pins
PD1 A11 MCDA5 144 and 217 pins
PD2 A12 MCDA6 144 and 217 pins
PD3 A13 MCDA7 144 and 217 pins
PD4 A14 TXD3 144 and 217 pins
PD5 A15 RXD3 144 and 217 pins
PD6 A16/BA0 PWMFI2 144 and 217 pins
PD7 A17/BA1 TIOA8 144 and 217 pins
PD8 A21/NANDALE TIOB8 144 and 217 pins
PD9 A22/NANDCLE TCLK8 144 and 217 pins
PD10 NWR1/NBS1 144 and 217 pins
PD11 SDA10 217 pins
PD12 SDCS 217 pins
PD13 SDCKE 217 pins
PD14 SDWE 217 pins
PD15 RAS 217 pins
PD16 CAS 217 pins
PD17 A5 217 pins
PD18 A6 217 pins
PD19 A7 217 pins
PD20 A8 217 pins
PD21 A9 217 pins
PD22 A10 217 pins
PD23 A11 217 pins
PD24 A12 217 pins
PD25 A13 217 pins
PD26 A14 217 pins
PD27 A15 217 pins
PD28 A16/BA0 217 pins
PD29 A17/BA1 217 pins
PD30 A18 217 pins
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9.3.5 PIO Controller E Multiplexing
Table 9-6. Multiplexing on PIO Controller E (PIOE)
I/O Line Peripheral A Peripheral B Extra Function Comments
PE0 A19 217 pins
PE1 A20 217 pins
PE2 A21/NANDALE 217 pins
PE3 A22/NANDCLE 217 pins
PE4 A23 217 pins
PE5 NCS4 217 pins
PE6 NCS5 217 pins
PE7 217 pins
PE8 217 pins
PE9 TIOA3 217 pins
PE10 TIOB3 217 pins
PE11 TIOA4 217 pins
PE12 TIOB4 217 pins
PE13 TIOA5 217 pins
PE14 TIOB5 217 pins
PE15 PWMH0 217 pins
PE16 PWMH1 SCK3 217 pins
PE17 PWML2 217 pins
PE18 PWML0 NCS6 217 pins
PE19 PWML4 217 pins
PE20 PWMH4 MCCDB 217 pins
PE21 PWML5 217 pins
PE22 PWMH5 MCDB0 217 pins
PE23 PWML6 217 pins
PE24 PWMH6 MCDB1 217 pins
PE25 PWML7 217 pins
PE26 PWMH7 MCDB2 217 pins
PE27 NCS7 MCDB3 217 pins
PE28 SPI1_MISO 217 pins
PE29 SPI1_MOSI 217 pins
PE30 SPI1_SPCK 217 pins
PE31 SPI1_NPCS0 217 pins
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9.3.6 PIO Controller F Multiplexing
Table 9-7. Multiplexing on PIO Controller F (PIOF)
I/O Line Peripheral A Peripheral B Extra Function Comments
PF0 SPI1_NPCS1 217 pins
PF1 SPI1_NPCS2 217 pins
PF2 SPI1_NPCS3 217 pins
PF3 PWMH3 217 pins
PF4 CTS3 217 pins
PF5 RTS3 217 pins
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10. ARM Cortex® M3 Processor
10.1 About this section
This section provides the information required for application and system-level software development. It does not
provide information on debug components, features, or operation.
This material is for microcontroller software and hardware engineers, including those who have no experience of
ARM products.
Note: The information in this section is reproduced from source material provided to Atmel by ARM Ltd. in terms of
Atmel’s license for the ARM Cortex™-M3 processor core. This information is copyright ARM Ltd., 2008 - 2009.
10.2 Embedded Characteristics
Version 2.0
Thumb-2 (ISA) subset consisting of all base Thumb-2 instructions, 16-bit and 32-bit.
Harvard processor architecture enabling simultaneous instruction fetch with data load/store.
Three-stage pipeline.
Single cycle 32-bit multiply.
Hardware divide.
Thumb and Debug states.
Handler and Thread modes.
Low latency ISR entry and exit.
SysTick Timer
̶24-bit down counter
̶Self-reload capability
̶Flexible system timer
Nested Vectored Interrupt Controller
̶Thirty maskable interrupts
̶Sixteen priority levels
̶Dynamic reprioritization of interrupts
̶Priority grouping
selection of preempting interrupt levels and non preempting interrupt levels.
̶Support for tail-chaining and late arrival of interrupts.
back-to-back interrupt processing without the overhead of state saving and restoration between
interrupts.
̶Processor state automatically saved on interrupt entry, and restored on interrupt exit, with no
instruction overhead.
10.3 About the Cortex-M3 processor and core peripherals
The Cortex-M3 processor is a high performance 32-bit processor designed for the microcontroller market. It
offers significant benefits to developers, including:
outstanding processing performance combined with fast interrupt handling
enhanced system debug with extensive breakpoint and trace capabilities
efficient processor core, system and memories
ultra-low power consumption with integrated sleep modes
platform security, with integrated memory protection unit (MPU).
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Figure 10-1. Typical Cortex-M3 implementation
The Cortex-M3 processor is built on a high-performance processor core, with a 3-stage pipeline Harvard
architecture, making it ideal for demanding embedded applications. The processor delivers exceptional power
efficiency through an efficient instruction set and extensively optimized design, providing high-end processing
hardware including single-cycle 32x32 multiplication and dedicated hardware division.
To facilitate the design of cost-sensitive devices, the Cortex-M3 processor implements tightly-coupled system
components that reduce processor area while significantly improving interrupt handling and system debug
capabilities. The Cortex-M3 processor implements a version of the Thumb® instruction set, ensuring high code
density and reduced program memory requirements. The Cortex-M3 instruction set provides the exceptional
performance expected of a modern 32-bit architecture, with the high code density of 8-bit and 16-bit
microcontrollers.
The Cortex-M3 processor closely integrates a configurable nested interrupt controller (NVIC), to deliver industry-
leading interrupt performance. The NVIC provides up to 16 interrupt priority levels. The tight integration of the
processor core and NVIC provides fast execution of interrupt service routines (ISRs), dramatically reducing the
interrupt latency. This is achieved through the hardware stacking of registers, and the ability to suspend load-
multiple and store-multiple operations. Interrupt handlers do not require any assembler stubs, removing any code
overhead from the ISRs. Tail-chaining optimization also significantly reduces the overhead when switching from
one ISR to another.
To optimize low-power designs, the NVIC integrates with the sleep modes, that include a deep sleep function that
enables the entire device to be rapidly powered down.
10.3.1 System level interface
The Cortex-M3 processor provides multiple interfaces using AMBA® technology to provide high speed, low latency
memory accesses. It supports unaligned data accesses and implements atomic bit manipulation that enables
faster peripheral controls, system spinlocks and thread-safe Boolean data handling.
The Cortex-M3 processor has a memory protection unit (MPU) that provides fine grain memory control, enabling
applications to implement security privilege levels, separating code, data and stack on a task-by-task basis. Such
requirements are becoming critical in many embedded applications.
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10.3.2 Integrated configurable debug
The Cortex-M3 processor implements a complete hardware debug solution. This provides high system visibility of
the processor and memory through either a traditional JTAG port or a 2-pin Serial Wire Debug (SWD) port that is
ideal for microcontrollers and other small package devices.
For system trace the processor integrates an Instrumentation Trace Macrocell (ITM) alongside data watchpoints
and a profiling unit. To enable simple and cost-effective profiling of the system events these generate, a Serial
Wire Viewer (SWV) can export a stream of software-generated messages, data trace, and profiling information
through a single pin.
10.3.3 Cortex-M3 processor features and benefits summary
tight integration of system peripherals reduces area and development costs
Thumb instruction set combines high code density with 32-bit performance
code-patch ability for ROM system updates
power control optimization of system components
integrated sleep modes for low power consumption
fast code execution permits slower processor clock or increases sleep mode time
hardware division and fast multiplier
deterministic, high-performance interrupt handling for time-critical applications
memory protection unit (MPU) for safety-critical applications
extensive debug and trace capabilities:
̶Serial Wire Debug and Serial Wire Trace reduce the number of pins required for debugging and
tracing.
10.3.4 Cortex-M3 core peripherals
These are:
10.3.4.1 Nested Vectored Interrupt Controller
The Nested Vectored Interrupt Controller (NVIC) is an embedded interrupt controller that supports low latency
interrupt processing.
10.3.4.2 System control block
The System control block (SCB) is the programmers model interface to the processor. It provides system
implementation information and system control, including configuration, control, and reporting of system
exceptions.
10.3.4.3 System timer
The system timer, SysTick, is a 24-bit count-down timer. Use this as a Real Time Operating System (RTOS) tick
timer or as a simple counter.
10.3.4.4 Memory protection unit
The Memory protection unit (MPU) improves system reliability by defining the memory attributes for different
memory regions. It provides up to eight different regions, and an optional predefined background region.
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10.4 Programmers model
This section describes the Cortex-M3 programmers model. In addition to the individual core register descriptions, it
contains information about the processor modes and privilege levels for software execution and stacks.
10.4.1 Processor mode and privilege levels for software execution
The processor modes are:
10.4.1.1 Thread mode
Used to execute application software. The processor enters Thread mode when it comes out of reset.
10.4.1.2 Handler mode
Used to handle exceptions. The processor returns to Thread mode when it has finished exception processing.
The privilege levels for software execution are:
10.4.1.3 Unprivileged
The software:
has limited access to the MSR and MRS instructions, and cannot use the CPS instruction
cannot access the system timer, NVIC, or system control block
might have restricted access to memory or peripherals.
Unprivileged software executes at the unprivileged level.
10.4.1.4 Privileged
The software can use all the instructions and has access to all resources.
Privileged software executes at the privileged level.
In Thread mode, the CONTROL register controls whether software execution is privileged or unprivileged, see
“CONTROL register” on page 60. In Handler mode, software execution is always privileged.
Only privileged software can write to the CONTROL register to change the privilege level for software execution in
Thread mode. Unprivileged software can use the SVC instruction to make a supervisor call to transfer control to
privileged software.
10.4.2 Stacks
The processor uses a full descending stack. This means the stack pointer indicates the last stacked item on the
stack memory. When the processor pushes a new item onto the stack, it decrements the stack pointer and then
writes the item to the new memory location. The processor implements two stacks, the main stack and the process
stack, with independent copies of the stack pointer, see “Stack Pointer” on page 52.
In Thread mode, the CONTROL register controls whether the processor uses the main stack or the process stack,
see “CONTROL register” on page 60. In Handler mode, the processor always uses the main stack. The options for
processor operations are:
Table 10-1. Summary of processor mode, execution privilege level, and stack use options
Processor mode Used to execute Privilege level for software execution Stack used
Thread Applications Privileged or unprivileged (1)
1. See “CONTROL register” on page 60.
Main stack or process stack(1)
Handler Exception handlers Always privileged Main stack
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10.4.3 Core registers
The processor core registers are:
Table 10-2. Core register set summary
Name Type (1)
1. Describes access type during program execution in thread mode and Handler mode. Debug access can differ.
Required privilege (2)
2. An entry of Either means privileged and unprivileged software can access the register.
Reset value Description
R0-R12 RW Either Unknown “General-purpose registers” on page 52
MSP RW Privileged See description “Stack Pointer” on page 52
PSP RW Either Unknown “Stack Pointer” on page 52
LR RW Either 0xFFFFFFFF “Link Register” on page 52
PC RW Either See description “Program Counter” on page 52
PSR RW Privileged
0x01000000
“Program Status Register” on page 52
ASPR RW Either 0x00000000 “Application Program Status Register” on page 54
IPSR RO Privileged 0x00000000 “Interrupt Program Status Register” on page 54
EPSR RO Privileged 0x01000000 “Execution Program Status Register” on page 55
PRIMASK RW Privileged 0x00000000 “Priority Mask Register” on page 57
FAULTMASK RW Privileged 0x00000000 “Fault Mask Register” on page 58
BASEPRI RW Privileged 0x00000000 “Base Priority Mask Register” on page 59
CONTROL RW Privileged 0x00000000 “CONTROL register” on page 60
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10.4.3.1 General-purpose registers
R0-R12 are 32-bit general-purpose registers for data operations.
10.4.3.2 Stack Pointer
The Stack Pointer (SP) is register R13. In Thread mode, bit[1] of the CONTROL register indicates the stack pointer
to use:
0 = Main Stack Pointer (MSP). This is the reset value.
1 = Process Stack Pointer (PSP).
On reset, the processor loads the MSP with the value from address
0x00000000
.
10.4.3.3 Link Register
The Link Register (LR) is register R14. It stores the return information for subroutines, function calls, and
exceptions. On reset, the processor loads the LR value
0xFFFFFFFF
.
10.4.3.4 Program Counter
The Program Counter (PC) is register R15. It contains the current program address. Bit[0] is always 0 because
instruction fetches must be halfword aligned. On reset, the processor loads the PC with the value of the reset
vector, which is at address
0x00000004
.
10.4.3.5 Program Status Register
The Program Status Register (PSR) combines:
Application Program Status Register (APSR)
Interrupt Program Status Register (IPSR)
Execution Program Status Register (EPSR).
These registers are mutually exclusive bitfields in the 32-bit PSR. The bit assignments are:
•APSR:
• IPSR:
3130292827 26 25 24
NZCVQ Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
Reserved
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved ISR_NUMBER
76543210
ISR_NUMBER
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• EPSR:
The PSR bit assignments are:
Access these registers individually or as a combination of any two or all three registers, using the register name as
an argument to the MSR or MRS instructions. For example:
read all of the registers using PSR with the MRS instruction
write to the APSR using APSR with the MSR instruction.
The PSR combinations and attributes are:
See the instruction descriptions “MRS” on page 146 and “MSR” on page 147 for more information about how to
access the program status registers.
3130292827 26 25 24
Reserved ICI/IT T
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
ICI/IT Reserved
76543210
Reserved
3130292827 26 25 24
NZCVQ ICI/IT T
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
ICI/IT Reserved ISR_NUMBER
76543210
ISR_NUMBER
Table 10-3. PSR register combinations
Register Type Combination
PSR RW (1), (2)
1. The processor ignores writes to the IPSR bits.
2. Reads of the EPSR bits return zero, and the
processor ignores writes to the these bits.
APSR, EPSR, and IPSR
IEPSR RO EPSR and IPSR
IAPSR RW(1) APSR and IPSR
EAPSR RW(2) APSR and EPSR
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10.4.3.6 Application Program Status Register
The APSR contains the current state of the condition flags from previous instruction executions. See the register
summary in Table 10-2 on page 51 for its attributes. The bit assignments are:
•N
Negative or less than flag:
0 = operation result was positive, zero, greater than, or equal
1 = operation result was negative or less than.
•Z
Zero flag:
0 = operation result was not zero
1 = operation result was zero.
•C
Carry or borrow flag:
0 = add operation did not result in a carry bit or subtract operation resulted in a borrow bit
1 = add operation resulted in a carry bit or subtract operation did not result in a borrow bit.
•V
Overflow flag:
0 = operation did not result in an overflow
1 = operation resulted in an overflow.
•Q
Sticky saturation flag:
0 = indicates that saturation has not occurred since reset or since the bit was last cleared to zero
1 = indicates when an
SSAT
or
USAT
instruction results in saturation.
This bit is cleared to zero by software using an
MRS
instruction.
10.4.3.7 Interrupt Program Status Register
The IPSR contains the exception type number of the current Interrupt Service Routine (ISR). See the register
summary in Table 10-2 on page 51 for its attributes. The bit assignments are:
• ISR_NUMBER
This is the number of the current exception:
0 = Thread mode
1 = Reserved
2 = NMI
3 = Hard fault
4 = Memory management fault
5 = Bus fault
6 = Usage fault
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7-10 = Reserved
11 = SVCall
12 = Reserved for Debug
13 = Reserved
14 = PendSV
15 = SysTick
16 = IRQ0
45 = IRQ29
see “Exception types” on page 71 for more information.
10.4.3.8 Execution Program Status Register
The EPSR contains the Thumb state bit, and the execution state bits for either the:
If-Then (IT) instruction
Interruptible-Continuable Instruction (ICI) field for an interrupted load multiple or store multiple instruction.
See the register summary in Table 10-2 on page 51 for the EPSR attributes. The bit assignments are:
•ICI
Interruptible-continuable instruction bits, see “Interruptible-continuable instructions” on page 55.
•IT
Indicates the execution state bits of the
IT
instruction, see “IT” on page 137.
•T
Always set to 1.
Attempts to read the EPSR directly through application software using the MSR instruction always return zero.
Attempts to write the EPSR using the MSR instruction in application software are ignored. Fault handlers can
examine EPSR value in the stacked PSR to indicate the operation that is at fault. See “Exception entry and return”
on page 75.
10.4.3.9 Interruptible-continuable instructions
When an interrupt occurs during the execution of an LDM or STM instruction, the processor:
stops the load multiple or store multiple instruction operation temporarily
stores the next register operand in the multiple operation to EPSR bits[15:12].
After servicing the interrupt, the processor:
returns to the register pointed to by bits[15:12]
resumes execution of the multiple load or store instruction.
When the EPSR holds ICI execution state, bits[26:25,11:10] are zero.
10.4.3.10 If-Then block
The If-Then block contains up to four instructions following a 16-bit IT instruction. Each instruction in the block is
conditional. The conditions for the instructions are either all the same, or some can be the inverse of others. See
“IT” on page 137 for more information.
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10.4.3.11 Exception mask registers
The exception mask registers disable the handling of exceptions by the processor. Disable exceptions where they
might impact on timing critical tasks.
To access the exception mask registers use the MSR and MRS instructions, or the CPS instruction to change the
value of PRIMASK or FAULTMASK. See “MRS” on page 146, “MSR” on page 147, and “CPS” on page 143 for
more information.
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10.4.3.12 Priority Mask Register
The PRIMASK register prevents activation of all exceptions with configurable priority. See the register summary in
Table 10-2 on page 51 for its attributes. The bit assignments are:
•PRIMASK
0: no effect
1: prevents the activation of all exceptions with configurable priority.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
Reserved PRIMASK
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10.4.3.13 Fault Mask Register
The FAULTMASK register prevents activation of all exceptions. See the register summary in Table 10-2 on page
51 for its attributes. The bit assignments are:
• FAULTMASK
0: no effect
1: prevents the activation of all exceptions.
The processor clears the FAULTMASK bit to 0 on exit from any exception handler except the NMI handler.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
Reserved FAULTMASK
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10.4.3.14 Base Priority Mask Register
The BASEPRI register defines the minimum priority for exception processing. When BASEPRI is set to a nonzero
value, it prevents the activation of all exceptions with same or lower priority level as the BASEPRI value. See the
register summary in Table 10-2 on page 51 for its attributes. The bit assignments are:
• BASEPRI
Priority mask bits:
0x0000
= no effect
Nonzero = defines the base priority for exception processing.
The processor does not process any exception with a priority value greater than or equal to BASEPRI.
This field is similar to the priority fields in the interrupt priority registers. The processor implements only bits[7:4] of this
field, bits[3:0] read as zero and ignore writes. See “Interrupt Priority Registers” on page 160 for more information. Remem-
ber that higher priority field values correspond to lower exception priorities.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
BASEPRI
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10.4.3.15 CONTROL register
The CONTROL register controls the stack used and the privilege level for software execution when the processor
is in Thread mode. See the register summary in Table 10-2 on page 51 for its attributes. The bit assignments are:
• Active stack pointer
Defines the current stack:
0: MSP is the current stack pointer
1: PSP is the current stack pointer.
In Handler mode this bit reads as zero and ignores writes.
• Thread mode privilege level
Defines the Thread mode privilege level:
0: privileged
1: unprivileged.
Handler mode always uses the MSP, so the processor ignores explicit writes to the active stack pointer bit of the CON-
TROL register when in Handler mode. The exception entry and return mechanisms update the CONTROL register.
In an OS environment, ARM recommends that threads running in Thread mode use the process stack and the kernel and
exception handlers use the main stack.
By default, Thread mode uses the MSP. To switch the stack pointer used in Thread mode to the PSP, use the MSR
instruction to set the Active stack pointer bit to 1, see “MSR” on page 147.
When changing the stack pointer, software must use an ISB instruction immediately after the MSR instruction. This
ensures that instructions after the ISB execute using the new stack pointer. See “ISB” on page 145
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
Reserved Active Stack
Pointer
Thread Mode
Privilege
Level
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10.4.4 Exceptions and interrupts
The Cortex-M3 processor supports interrupts and system exceptions. The processor and the Nested Vectored
Interrupt Controller (NVIC) prioritize and handle all exceptions. An exception changes the normal flow of software
control. The processor uses handler mode to handle all exceptions except for reset. See “Exception entry” on page
76 and “Exception return” on page 76 for more information.
The NVIC registers control interrupt handling. See “Nested Vectored Interrupt Controller” on page 152 for more
information.
10.4.5 Data types
The processor:
supports the following data types:
̶32-bit words
̶16-bit halfwords
̶8-bit bytes
supports 64-bit data transfer instructions.
manages all data memory accesses as little-endian. Instruction memory and Private Peripheral Bus (PPB)
accesses are always little-endian. See “Memory regions, types and attributes” on page 62 for more
information.
10.4.6 The Cortex Microcontroller Software Interface Standard
For a Cortex-M3 microcontroller system, the Cortex Microcontroller Software Interface Standard (CMSIS) defines:
a common way to:
̶access peripheral registers
̶define exception vectors
the names of:
̶the registers of the core peripherals
̶the core exception vectors
a device-independent interface for RTOS kernels, including a debug channel.
The CMSIS includes address definitions and data structures for the core peripherals in the Cortex-M3 processor. It
also includes optional interfaces for middleware components comprising a TCP/IP stack and a Flash file system.
CMSIS simplifies software development by enabling the reuse of template code and the combination of CMSIS-
compliant software components from various middleware vendors. Software vendors can expand the CMSIS to
include their peripheral definitions and access functions for those peripherals.
This document includes the register names defined by the CMSIS, and gives short descriptions of the CMSIS
functions that address the processor core and the core peripherals.
This document uses the register short names defined by the CMSIS. In a few cases these differ from the
architectural short names that might be used in other documents.
The following sections give more information about the CMSIS:
“Power management programming hints” on page 81
“Intrinsic functions” on page 85
“The CMSIS mapping of the Cortex-M3 NVIC registers” on page 153
“NVIC programming hints” on page 164.
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10.5 Memory model
This section describes the processor memory map, the behavior of memory accesses, and the bit-banding
features. The processor has a fixed memory map that provides up to 4GB of addressable memory. The memory
map is:
The regions for SRAM and peripherals include bit-band regions. Bit-banding provides atomic operations to bit
data, see “Bit-banding” on page 66.
The processor reserves regions of the Private peripheral bus (PPB) address range for core peripheral registers,
see “About the Cortex-M3 peripherals” on page 152.
This memory mapping is generic to ARM Cortex-M3 products. To get the specific memory mapping of this product,
refer to the Memories section of the datasheet.
10.5.1 Memory regions, types and attributes
The memory map and the programming of the MPU split the memory map into regions. Each region has a defined
memory type, and some regions have additional memory attributes. The memory type and attributes determine the
behavior of accesses to the region.
The memory types are:
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10.5.1.1 Normal
The processor can re-order transactions for efficiency, or perform speculative reads.
10.5.1.2 Device
The processor preserves transaction order relative to other transactions to Device or Strongly-ordered memory.
10.5.1.3 Strongly-ordered
The processor preserves transaction order relative to all other transactions.
The different ordering requirements for Device and Strongly-ordered memory mean that the memory system can
buffer a write to Device memory, but must not buffer a write to Strongly-ordered memory.
The additional memory attributes include.
10.5.1.4 Shareable
For a shareable memory region, the memory system provides data synchronization between bus masters in a
system with multiple bus masters, for example, a processor with a DMA controller.
Strongly-ordered memory is always shareable.
If multiple bus masters can access a non-shareable memory region, software must ensure data coherency
between the bus masters.
10.5.1.5 Execute Never (XN)
Means the processor prevents instruction accesses. Any attempt to fetch an instruction from an XN region causes
a memory management fault exception.
10.5.2 Memory system ordering of memory accesses
For most memory accesses caused by explicit memory access instructions, the memory system does not
guarantee that the order in which the accesses complete matches the program order of the instructions, providing
this does not affect the behavior of the instruction sequence. Normally, if correct program execution depends on
two memory accesses completing in program order, software must insert a memory barrier instruction between the
memory access instructions, see “Software ordering of memory accesses” on page 65.
However, the memory system does guarantee some ordering of accesses to Device and Strongly-ordered
memory. For two memory access instructions A1 and A2, if A1 occurs before A2 in program order, the ordering of
the memory accesses caused by two instructions is:
Where:
- Means that the memory system does not guarantee the ordering of the accesses.
< Means that accesses are observed in program order, that is, A1 is always observed before A2.
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10.5.3 Behavior of memory accesses
The behavior of accesses to each region in the memory map is:
The Code, SRAM, and external RAM regions can hold programs. However, ARM recommends that programs
always use the Code region. This is because the processor has separate buses that enable instruction fetches and
data accesses to occur simultaneously.
The MPU can override the default memory access behavior described in this section. For more information, see
“Memory protection unit” on page 197.
Table 10-4. Memory access behavior
Address
range Memory
region Memory
type XN Description
0x00000000
-
0x1FFFFFFF
Code Normal (1)
1. See “Memory regions, types and attributes” on page 62 for more information.
-Executable region for program code. You can also put
data here.
0x20000000
-
0x3FFFFFFF
SRAM Normal(1) -
Executable region for data. You can also put code
here.
This region includes bit band and bit band alias areas,
see Table 10-6 on page 67.
0x40000000
-
0x5FFFFFFF
Peripheral Device(1) XN This region includes bit band and bit band alias areas,
see Table 10-6 on page 67.
0x60000000
-
0x9FFFFFFF
External
RAM Normal(1) - Executable region for data.
0xA0000000
-
0xDFFFFFFF
External
device Device(1) XN External Device memory
0xE0000000
-
0xE00FFFFF
Private
Peripheral
Bus
Strongly-
ordered(1) XN This region includes the NVIC, System timer, and
system control block.
0xE0100000
-
0xFFFFFFFF
Reserved Device(1) XN Reserved
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10.5.3.1 Additional memory access constraints for shared memory
When a system includes shared memory, some memory regions have additional access constraints, and some
regions are subdivided, as Table 10-5 shows:
10.5.4 Software ordering of memory accesses
The order of instructions in the program flow does not always guarantee the order of the corresponding memory
transactions. This is because:
the processor can reorder some memory accesses to improve efficiency, providing this does not affect the
behavior of the instruction sequence.
the processor has multiple bus interfaces
memory or devices in the memory map have different wait states
some memory accesses are buffered or speculative.
“Memory system ordering of memory accesses” on page 63 describes the cases where the memory system
guarantees the order of memory accesses. Otherwise, if the order of memory accesses is critical, software must
include memory barrier instructions to force that ordering. The processor provides the following memory barrier
instructions:
10.5.4.1
DMB
The Data Memory Barrier (DMB) instruction ensures that outstanding memory transactions complete before
subsequent memory transactions. See “DMB” on page 144.
Table 10-5. Memory region share ability policies
Address range Memory region Memory type Shareability
0x00000000
-
0x1FFFFFFF
Code Normal (1)
1. See “Memory regions, types and attributes” on page 62 for more information.
-
0x20000000
-
0x3FFFFFFF
SRAM Normal(1) -
0x40000000
-
0x5FFFFFFF
Peripheral (2)
2. The Peripheral and Vendor-specific device regions have no additional access constraints.
Device(1) -
0x60000000
-
0x7FFFFFFF
External RAM Normal(1) -
WBWA(2)
0x80000000
-
0x9FFFFFFF
WT(2)
0xA0000000
-
0xBFFFFFFF
External device Device(1)
Shareable(1)
-
0xC0000000
-
0xDFFFFFFF
Non-
shareable(1)
0xE0000000
-
0xE00FFFFF
Private Peripheral
Bus Strongly-
ordered(1) Shareable(1) -
0xE0100000
-
0xFFFFFFFF
Vendor-specific
device(2) Device(1) --
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10.5.4.2
DSB
The Data Synchronization Barrier (DSB) instruction ensures that outstanding memory transactions complete
before subsequent instructions execute. See “DSB” on page 144.
10.5.4.3
ISB
The Instruction Synchronization Barrier (ISB) ensures that the effect of all completed memory transactions is
recognizable by subsequent instructions. See “ISB” on page 145.
Use memory barrier instructions in, for example:
MPU programming:
̶Use a DSB instruction to ensure the effect of the MPU takes place immediately at the end of context
switching.
̶Use an ISB instruction to ensure the new MPU setting takes effect immediately after programming the
MPU region or regions, if the MPU configuration code was accessed using a branch or call. If the MPU
configuration code is entered using exception mechanisms, then an ISB instruction is not required.
Vector table. If the program changes an entry in the vector table, and then enables the corresponding
exception, use a DMB instruction between the operations. This ensures that if the exception is taken
immediately after being enabled the processor uses the new exception vector.
Self-modifying code. If a program contains self-modifying code, use an ISB instruction immediately after the
code modification in the program. This ensures subsequent instruction execution uses the updated program.
Memory map switching. If the system contains a memory map switching mechanism, use a DSB instruction
after switching the memory map in the program. This ensures subsequent instruction execution uses the
updated memory map.
Dynamic exception priority change. When an exception priority has to change when the exception is pending
or active, use DSB instructions after the change. This ensures the change takes effect on completion of the
DSB instruction.
Using a semaphore in multi-master system. If the system contains more than one bus master, for example, if
another processor is present in the system, each processor must use a DMB instruction after any
semaphore instructions, to ensure other bus masters see the memory transactions in the order in which they
were executed.
Memory accesses to Strongly-ordered memory, such as the system control block, do not require the use of DMB
instructions.
10.5.5 Bit-banding
A bit-band region maps each word in a bit-band alias region to a single bit in the bit-band region. The bit-band
regions occupy the lowest 1MB of the SRAM and peripheral memory regions.
The memory map has two 32MB alias regions that map to two 1MB bit-band regions:
accesses to the 32MB SRAM alias region map to the 1MB SRAM bit-band region, as shown in Table 10-6
accesses to the 32MB peripheral alias region map to the 1MB peripheral bit-band region, as shown in Table
10-7.
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A word access to the SRAM or peripheral bit-band alias regions map to a single bit in the SRAM or peripheral bit-
band region.
The following formula shows how the alias region maps onto the bit-band region:
bit_word_offset = (byte_offset x 32) + (bit_number x 4)
bit_word_addr = bit_band_base + bit_word_offset
where:
Bit_word_offset
is the position of the target bit in the bit-band memory region.
Bit_word_addr
is the address of the word in the alias memory region that maps to the targeted bit.
Bit_band_base
is the starting address of the alias region.
Byte_offset
is the number of the byte in the bit-band region that contains the targeted bit.
Bit_number
is the bit position, 0-7, of the targeted bit.
Figure 10-2 shows examples of bit-band mapping between the SRAM bit-band alias region and the SRAM bit-
band region:
The alias word at
0x23FFFFE0
maps to bit[0] of the bit-band byte at
0x200FFFFF
:
0x23FFFFE0
=
0x22000000
+
(
0xFFFFF
*32) + (0*4).
The alias word at
0x23FFFFFC
maps to bit[7] of the bit-band byte at
0x200FFFFF
:
0x23FFFFFC
=
0x22000000
+
(
0xFFFFF
*32) + (7*4).
The alias word at
0x22000000
maps to bit[0] of the bit-band byte at
0x20000000
:
0x22000000
=
0x22000000
+
(0*32) + (0 *4).
The alias word at
0x2200001C
maps to bit[7] of the bit-band byte at
0x20000000
:
0x2200001C
=
0x22000000
+
(0*32) + (7*4).
Table 10-6. SRAM memory bit-banding regions
Address
range Memory
region Instruction and data accesses
0x20000000
-
0x200FFFFF
SRAM bit-band
region
Direct accesses to this memory range behave as SRAM
memory accesses, but this region is also bit addressable
through bit-band alias.
0x22000000
-
0x23FFFFFF SRAM bit-band alias Data accesses to this region are remapped to bit band
region. A write operation is performed as read-modify-write.
Instruction accesses are not remapped.
Table 10-7. Peripheral memory bit-banding regions
Address
range Memory
region Instruction and data accesses
0x40000000-
0x400FFFFF
Peripheral bit-band
alias
Direct accesses to this memory range behave as peripheral
memory accesses, but this region is also bit addressable
through bit-band alias.
0x42000000-
0x43FFFFFF
Peripheral bit-band
region
Data accesses to this region are remapped to bit band
region. A write operation is performed as read-modify-write.
Instruction accesses are not permitted.
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Figure 10-2. Bit-band mapping
10.5.5.1 Directly accessing an alias region
Writing to a word in the alias region updates a single bit in the bit-band region.
Bit[0] of the value written to a word in the alias region determines the value written to the targeted bit in the bit-
band region. Writing a value with bit[0] set to 1 writes a 1 to the bit-band bit, and writing a value with bit[0] set to 0
writes a 0 to the bit-band bit.
Bits[31:1] of the alias word have no effect on the bit-band bit. Writing
0x01
has the same effect as writing
0xFF
.
Writing
0x00
has the same effect as writing
0x0E
.
Reading a word in the alias region:
0x00000000
indicates that the targeted bit in the bit-band region is set to zero
0x00000001
indicates that the targeted bit in the bit-band region is set to 1
10.5.5.2 Directly accessing a bit-band region
“Behavior of memory accesses” on page 64 describes the behavior of direct byte, halfword, or word accesses to
the bit-band regions.
10.5.6 Memory endianness
The processor views memory as a linear collection of bytes numbered in ascending order from zero. For example,
bytes 0-3 hold the first stored word, and bytes 4-7 hold the second stored word. or “Little-endian format” describes
how words of data are stored in memory.
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10.5.6.1 Little-endian format
In little-endian format, the processor stores the least significant byte of a word at the lowest-numbered byte, and
the most significant byte at the highest-numbered byte. For example:
10.5.7 Synchronization primitives
The Cortex-M3 instruction set includes pairs of synchronization primitives. These provide a non-blocking
mechanism that a thread or process can use to obtain exclusive access to a memory location. Software can use
them to perform a guaranteed read-modify-write memory update sequence, or for a semaphore mechanism.
A pair of synchronization primitives comprises:
10.5.7.1 A Load-Exclusive instruction
Used to read the value of a memory location, requesting exclusive access to that location.
10.5.7.2 A Store-Exclusive instruction
Used to attempt to write to the same memory location, returning a status bit to a register. If this bit is:
0: it indicates that the thread or process gained exclusive access to the memory, and the write succeeds,
1: it indicates that the thread or process did not gain exclusive access to the memory, and no write is performed,
The pairs of Load-Exclusive and Store-Exclusive instructions are:
the word instructions LDREX and STREX
the halfword instructions LDREXH and STREXH
the byte instructions LDREXB and STREXB.
Software must use a Load-Exclusive instruction with the corresponding Store-Exclusive instruction.
To perform a guaranteed read-modify-write of a memory location, software must:
Use a Load-Exclusive instruction to read the value of the location.
Update the value, as required.
Use a Store-Exclusive instruction to attempt to write the new value back to the memory location, and tests
the returned status bit. If this bit is:
0: The read-modify-write completed successfully,
1: No write was performed. This indicates that the value returned the first step might be out of date. The
software must retry the read-modify-write sequence,
Software can use the synchronization primitives to implement a semaphores as follows:
Use a Load-Exclusive instruction to read from the semaphore address to check whether the semaphore is
free.
If the semaphore is free, use a Store-Exclusive to write the claim value to the semaphore address.
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If the returned status bit from the second step indicates that the Store-Exclusive succeeded then the
software has claimed the semaphore. However, if the Store-Exclusive failed, another process might have
claimed the semaphore after the software performed the first step.
The Cortex-M3 includes an exclusive access monitor, that tags the fact that the processor has executed a Load-
Exclusive instruction. If the processor is part of a multiprocessor system, the system also globally tags the memory
locations addressed by exclusive accesses by each processor.
The processor removes its exclusive access tag if:
It executes a CLREX instruction
It executes a Store-Exclusive instruction, regardless of whether the write succeeds.
An exception occurs. This means the processor can resolve semaphore conflicts between different threads.
In a multiprocessor implementation:
executing a CLREX instruction removes only the local exclusive access tag for the processor
executing a Store-Exclusive instruction, or an exception. removes the local exclusive access tags, and all
global exclusive access tags for the processor.
For more information about the synchronization primitive instructions, see “LDREX and STREX” on page 106 and
“CLREX” on page 108.
10.5.8 Programming hints for the synchronization primitives
ANSI C cannot directly generate the exclusive access instructions. Some C compilers provide intrinsic functions
for generation of these instructions:
The actual exclusive access instruction generated depends on the data type of the pointer passed to the intrinsic
function. For example, the following C code generates the require LDREXB operation:
__ldrex((volatile char *) 0xFF);
10.6 Exception model
This section describes the exception model.
10.6.1 Exception states
Each exception is in one of the following states:
10.6.1.1 Inactive
The exception is not active and not pending.
10.6.1.2 Pending
The exception is waiting to be serviced by the processor.
An interrupt request from a peripheral or from software can change the state of the corresponding interrupt to
pending.
Table 10-8. C compiler intrinsic functions for exclusive access instructions
Instruction Intrinsic function
LDREX
,
LDREXH
, or
LDREXB
unsigned int __ldrex(volatile void *ptr)
STREX
,
STREXH
, or
STREXB
int __strex(unsigned int val, volatile void *ptr)
CLREX void __clrex(void)
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10.6.1.3 Active
An exception that is being serviced by the processor but has not completed.
An exception handler can interrupt the execution of another exception handler. In this case both exceptions are in
the active state.
10.6.1.4 Active and pending
The exception is being serviced by the processor and there is a pending exception from the same source.
10.6.2 Exception types
The exception types are:
10.6.2.1 Reset
Reset is invoked on power up or a warm reset. The exception model treats reset as a special form of exception.
When reset is asserted, the operation of the processor stops, potentially at any point in an instruction. When reset
is deasserted, execution restarts from the address provided by the reset entry in the vector table. Execution
restarts as privileged execution in Thread mode.
10.6.2.2 Non Maskable Interrupt (NMI)
A non maskable interrupt (NMI) can be signalled by a peripheral or triggered by software. This is the highest
priority exception other than reset. It is permanently enabled and has a fixed priority of -2.
NMIs cannot be:
Masked or prevented from activation by any other exception.
Preempted by any exception other than Reset.
10.6.2.3 Hard fault
A hard fault is an exception that occurs because of an error during exception processing, or because an exception
cannot be managed by any other exception mechanism. Hard faults have a fixed priority of -1, meaning they have
higher priority than any exception with configurable priority.
10.6.2.4 Memory management fault
A memory management fault is an exception that occurs because of a memory protection related fault. The MPU
or the fixed memory protection constraints determines this fault, for both instruction and data memory transactions.
This fault is used to abort instruction accesses to Execute Never (XN) memory regions, even if the MPU is
disabled.
10.6.2.5 Bus fault
A bus fault is an exception that occurs because of a memory related fault for an instruction or data memory
transaction. This might be from an error detected on a bus in the memory system.
10.6.2.6 Usage fault
A usage fault is an exception that occurs because of a fault related to instruction execution. This includes:
an undefined instruction
an illegal unaligned access
invalid state on instruction execution
an error on exception return.
The following can cause a usage fault when the core is configured to report them:
an unaligned address on word and halfword memory access
division by zero.
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10.6.2.7 SVCall
A supervisor call (SVC) is an exception that is triggered by the SVC instruction. In an OS environment, applications
can use SVC instructions to access OS kernel functions and device drivers.
10.6.2.8 PendSV
PendSV is an interrupt-driven request for system-level service. In an OS environment, use PendSV for context
switching when no other exception is active.
10.6.2.9 SysTick
A SysTick exception is an exception the system timer generates when it reaches zero. Software can also generate
a SysTick exception. In an OS environment, the processor can use this exception as system tick.
10.6.2.10 Interrupt (IRQ)
A interrupt, or IRQ, is an exception signalled by a peripheral, or generated by a software request. All interrupts are
asynchronous to instruction execution. In the system, peripherals use interrupts to communicate with the
processor.
For an asynchronous exception, other than reset, the processor can execute another instruction between when the
exception is triggered and when the processor enters the exception handler.
Table 10-9. Properties of the different exception types
Exception
number (1)
IRQ
number(
1) Exception
type Priority Vector address
or offset (2) Activation
1 - Reset -3, the highest 0x00000004 Asynchronous
2 -14 NMI -2 0x00000008 Asynchronous
3 -13 Hard fault -1 0x0000000C -
4 -12 Memory
management fault Configurable (3) 0x00000010 Synchronous
5 -11 Bus fault Configurable(3) 0x00000014 Synchronous when precise,
asynchronous when imprecise
6 -10 Usage fault Configurable(3) 0x00000018 Synchronous
7-10 - - - Reserved -
11 -5 SVCall Configurable(3) 0x0000002C Synchronous
12-13 - - - Reserved -
14 -2 PendSV Configurable(3) 0x00000038 Asynchronous
15 -1 SysTick Configurable(3)
0x0000003C
Asynchronous
16 and above 0 and
above (4) Interrupt (IRQ) Configurable (5)
0x00000040
and
above (6) Asynchronous
1. To simplify the software layer, the CMSIS only uses IRQ numbers and therefore uses negative values for exceptions other than
interrupts. The IPSR returns the Exception number, see “Interrupt Program Status Register” on page 54.
2. See “Vector table” on page 74 for more information.
3. See “System Handler Priority Registers” on page 177.
4. See the “Peripheral Identifiers” section of the datasheet.
5. See “Interrupt Priority Registers” on page 160.
6. Increasing in steps of 4.
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Privileged software can disable the exceptions that Table 10-9 on page 72 shows as having configurable priority,
see:
“System Handler Control and State Register” on page 180
“Interrupt Clear-enable Registers” on page 156.
For more information about hard faults, memory management faults, bus faults, and usage faults, see “Fault
handling” on page 78.
10.6.3 Exception handlers
The processor handles exceptions using:
10.6.3.1 Interrupt Service Routines (ISRs)
Interrupts IRQ0 to IRQ29 are the exceptions handled by ISRs.
10.6.3.2 Fault handlers
Hard fault, memory management fault, usage fault, bus fault are fault exceptions handled by the fault handlers.
10.6.3.3 System handlers
NMI, PendSV, SVCall SysTick, and the fault exceptions are all system exceptions that are handled by system
handlers.
10.6.4 Vector table
The vector table contains the reset value of the stack pointer, and the start addresses, also called exception
vectors, for all exception handlers. Figure 10-3 on page 74 shows the order of the exception vectors in the vector
table. The least-significant bit of each vector must be 1, indicating that the exception handler is Thumb code.
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Figure 10-3. Vector table
On system reset, the vector table is fixed at address
0x00000000
. Privileged software can write to the VTOR to
relocate the vector table start address to a different memory location, in the range
0x00000080
to
0x3FFFFF80
, see
“Vector Table Offset Register” on page 171.
10.6.5 Exception priorities
As Table 10-9 on page 72 shows, all exceptions have an associated priority, with:
a lower priority value indicating a higher priority
configurable priorities for all exceptions except Reset, Hard fault.
If software does not configure any priorities, then all exceptions with a configurable priority have a priority of 0. For
information about configuring exception priorities see
“System Handler Priority Registers” on page 177
“Interrupt Priority Registers” on page 160.
Configurable priority values are in the range 0-15. This means that the Reset, Hard fault, and NMI exceptions, with
fixed negative priority values, always have higher priority than any other exception.
Initial SP value
Reset
Hard fault
Reserved
Memory management fault
Usage fault
Bus fault
0x0000
0x0004
0x0008
0x000C
0x0010
0x0014
0x0018
Reserved
SVCall
PendSV
Reserved for Debug
Systick
IRQ0
Reserved
0x002C
0x0038
0x003C
0x0040
OffsetException number
2
3
4
5
6
11
12
14
15
16
18
13
7
10
1
Vector
.
.
.
8
9
IRQ1
IRQ2
0x0044
IRQ29
17
0x0048
0x004C
45
.
.
.
.
.
.
0x00B4
IRQ number
-14
-13
-12
-11
-10
-5
-2
-1
0
2
1
29
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For example, assigning a higher priority value to IRQ[0] and a lower priority value to IRQ[1] means that IRQ[1] has
higher priority than IRQ[0]. If both IRQ[1] and IRQ[0] are asserted, IRQ[1] is processed before IRQ[0].
If multiple pending exceptions have the same priority, the pending exception with the lowest exception number
takes precedence. For example, if both IRQ[0] and IRQ[1] are pending and have the same priority, then IRQ[0] is
processed before IRQ[1].
When the processor is executing an exception handler, the exception handler is preempted if a higher priority
exception occurs. If an exception occurs with the same priority as the exception being handled, the handler is not
preempted, irrespective of the exception number. However, the status of the new interrupt changes to pending.
10.6.6 Interrupt priority grouping
To increase priority control in systems with interrupts, the NVIC supports priority grouping. This divides each
interrupt priority register entry into two fields:
an upper field that defines the group priority
a lower field that defines a subpriority within the group.
Only the group priority determines preemption of interrupt exceptions. When the processor is executing an
interrupt exception handler, another interrupt with the same group priority as the interrupt being handled does not
preempt the handler,
If multiple pending interrupts have the same group priority, the subpriority field determines the order in which they
are processed. If multiple pending interrupts have the same group priority and subpriority, the interrupt with the
lowest IRQ number is processed first.
For information about splitting the interrupt priority fields into group priority and subpriority, see “Application
Interrupt and Reset Control Register” on page 172.
10.6.7 Exception entry and return
Descriptions of exception handling use the following terms:
10.6.7.1 Preemption
When the processor is executing an exception handler, an exception can preempt the exception handler if its
priority is higher than the priority of the exception being handled. See “Interrupt priority grouping” on page 75 for
more information about preemption by an interrupt.
When one exception preempts another, the exceptions are called nested exceptions. See “Exception entry” on
page 76 more information.
10.6.7.2 Return
This occurs when the exception handler is completed, and:
there is no pending exception with sufficient priority to be serviced
the completed exception handler was not handling a late-arriving exception.
The processor pops the stack and restores the processor state to the state it had before the interrupt occurred.
See “Exception return” on page 76 for more information.
10.6.7.3 Tail-chaining
This mechanism speeds up exception servicing. On completion of an exception handler, if there is a pending
exception that meets the requirements for exception entry, the stack pop is skipped and control transfers to the
new exception handler.
10.6.7.4 Late-arriving
This mechanism speeds up preemption. If a higher priority exception occurs during state saving for a previous
exception, the processor switches to handle the higher priority exception and initiates the vector fetch for that
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exception. State saving is not affected by late arrival because the state saved is the same for both exceptions.
Therefore the state saving continues uninterrupted. The processor can accept a late arriving exception until the
first instruction of the exception handler of the original exception enters the execute stage of the processor. On
return from the exception handler of the late-arriving exception, the normal tail-chaining rules apply.
10.6.7.5 Exception entry
Exception entry occurs when there is a pending exception with sufficient priority and either:
the processor is in Thread mode
the new exception is of higher priority than the exception being handled, in which case the new exception
preempts the original exception.
When one exception preempts another, the exceptions are nested.
Sufficient priority means the exception has more priority than any limits set by the mask registers, see “Exception
mask registers” on page 56. An exception with less priority than this is pending but is not handled by the
processor.
When the processor takes an exception, unless the exception is a tail-chained or a late-arriving exception, the
processor pushes information onto the current stack. This operation is referred as stacking and the structure of
eight data words is referred as stack frame. The stack frame contains the following information:
R0-R3, R12
Return address
PSR
LR.
Immediately after stacking, the stack pointer indicates the lowest address in the stack frame. Unless stack
alignment is disabled, the stack frame is aligned to a double-word address. If the STKALIGN bit of the
Configuration Control Register (CCR) is set to 1, stack align adjustment is performed during stacking.
The stack frame includes the return address. This is the address of the next instruction in the interrupted program.
This value is restored to the PC at exception return so that the interrupted program resumes.
In parallel to the stacking operation, the processor performs a vector fetch that reads the exception handler start
address from the vector table. When stacking is complete, the processor starts executing the exception handler. At
the same time, the processor writes an EXC_RETURN value to the LR. This indicates which stack pointer
corresponds to the stack frame and what operation mode the was processor was in before the entry occurred.
If no higher priority exception occurs during exception entry, the processor starts executing the exception handler
and automatically changes the status of the corresponding pending interrupt to active.
If another higher priority exception occurs during exception entry, the processor starts executing the exception
handler for this exception and does not change the pending status of the earlier exception. This is the late arrival
case.
10.6.7.6 Exception return
Exception return occurs when the processor is in Handler mode and executes one of the following instructions to
load the EXC_RETURN value into the PC:
a
POP
instruction that includes the PC
a
BX
instruction with any register.
an
LDR
or
LDM
instruction with the PC as the destination.
EXC_RETURN is the value loaded into the LR on exception entry. The exception mechanism relies on this value
to detect when the processor has completed an exception handler. The lowest four bits of this value provide
information on the return stack and processor mode. Table 10-10 shows the EXC_RETURN[3:0] values with a
description of the exception return behavior.
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The processor sets EXC_RETURN bits[31:4] to
0xFFFFFFF
. When this value is loaded into the PC it indicates to the
processor that the exception is complete, and the processor initiates the exception return sequence.
Table 10-10. Exception return behavior
EXC_RETURN[3:0] Description
bXXX0 Reserved.
b0001
Return to Handler mode.
Exception return gets state from MSP.
Execution uses MSP after return.
b0011 Reserved.
b01X1 Reserved.
b1001
Return to Thread mode.
Exception return gets state from MSP.
Execution uses MSP after return.
b1101
Return to Thread mode.
Exception return gets state from PSP.
Execution uses PSP after return.
b1X11 Reserved.
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10.7 Fault handling
Faults are a subset of the exceptions, see “Exception model” on page 70. The following generate a fault:
̶a bus error on:
̶an instruction fetch or vector table load
̶a data access
an internally-detected error such as an undefined instruction or an attempt to change state with a BX
instruction
attempting to execute an instruction from a memory region marked as Non-Executable (XN).
an MPU fault because of a privilege violation or an attempt to access an unmanaged region.
10.7.1 Fault types
Table 10-11 shows the types of fault, the handler used for the fault, the corresponding fault status register, and the
register bit that indicates that the fault has occurred. See “Configurable Fault Status Register” on page 182 for
more information about the fault status registers.
Table 10-11. Faults
Fault Handler Bit name Fault status register
Bus error on a vector read Hard fault VECTTBL “Hard Fault Status Register” on page 188
Fault escalated to a hard fault FORCED
MPU mismatch:
Memory
management
fault
--
on instruction access IACCVIOL (1)
1. Occurs on an access to an XN region even if the MPU is disabled.
“Memory Management Fault Address
Register” on page 189
on data access DACCVIOL
during exception stacking MSTKERR
during exception unstacking MUNSKERR
Bus error:
Bus fault
--
during exception stacking STKERR
“Bus Fault Status Register” on page 184
during exception unstacking UNSTKERR
during instruction prefetch IBUSERR
Precise data bus error PRECISERR
Imprecise data bus error IMPRECISERR
Attempt to access a coprocessor
Usage fault
NOCP
“Usage Fault Status Register” on page 186
Undefined instruction UNDEFINSTR
Attempt to enter an invalid instruction
set state (2)
2. Attempting to use an instruction set other than the Thumb instruction set.
INVSTATE
Invalid EXC_RETURN value INVPC
Illegal unaligned load or store UNALIGNED
Divide By 0 DIVBYZERO
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10.7.2 Fault escalation and hard faults
All faults exceptions except for hard fault have configurable exception priority, see “System Handler Priority
Registers” on page 177. Software can disable execution of the handlers for these faults, see “System Handler
Control and State Register” on page 180.
Usually, the exception priority, together with the values of the exception mask registers, determines whether the
processor enters the fault handler, and whether a fault handler can preempt another fault handler. as described in
“Exception model” on page 70.
In some situations, a fault with configurable priority is treated as a hard fault. This is called priority escalation, and
the fault is described as escalated to hard fault. Escalation to hard fault occurs when:
A fault handler causes the same kind of fault as the one it is servicing. This escalation to hard fault occurs
because a fault handler cannot preempt itself because it must have the same priority as the current priority
level.
A fault handler causes a fault with the same or lower priority as the fault it is servicing. This is because the
handler for the new fault cannot preempt the currently executing fault handler.
An exception handler causes a fault for which the priority is the same as or lower than the currently
executing exception.
A fault occurs and the handler for that fault is not enabled.
If a bus fault occurs during a stack push when entering a bus fault handler, the bus fault does not escalate to a
hard fault. This means that if a corrupted stack causes a fault, the fault handler executes even though the stack
push for the handler failed. The fault handler operates but the stack contents are corrupted.
Only Reset and NMI can preempt the fixed priority hard fault. A hard fault can preempt any exception other than
Reset, NMI, or another hard fault.
10.7.3 Fault status registers and fault address registers
The fault status registers indicate the cause of a fault. For bus faults and memory management faults, the fault
address register indicates the address accessed by the operation that caused the fault, as shown in Table 10-12.
10.7.4 Lockup
The processor enters a lockup state if a hard fault occurs when executing the hard fault handlers. When the
processor is in lockup state it does not execute any instructions. The processor remains in lockup state until:
it is reset
Table 10-12. Fault status and fault address registers
Handler Status register
name Address register
name Register description
Hard fault HFSR - “Hard Fault Status Register” on page 188
Memory
management fault MMFSR MMFAR “Memory Management Fault Status Register” on page 183
“Memory Management Fault Address Register” on page 189
Bus fault BFSR BFAR “Bus Fault Status Register” on page 184
“Bus Fault Address Register” on page 190
Usage fault UFSR - “Usage Fault Status Register” on page 186
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10.8 Power management
The Cortex-M3 processor sleep modes reduce power consumption:
Backup Mode
Wait Mode
Sleep Mode
The SLEEPDEEP bit of the SCR selects which sleep mode is used, see “System Control Register” on page 174.
For more information about the behavior of the sleep modes see “Low Power Modes” in the PMC section of the
datasheet.
This section describes the mechanisms for entering sleep mode, and the conditions for waking up from sleep
mode.
10.8.1 Entering sleep mode
This section describes the mechanisms software can use to put the processor into sleep mode.
The system can generate spurious wakeup events, for example a debug operation wakes up the processor.
Therefore software must be able to put the processor back into sleep mode after such an event. A program might
have an idle loop to put the processor back to sleep mode.
10.8.1.1 Wait for interrupt
The wait for interrupt instruction, WFI, causes immediate entry to sleep mode. When the processor executes a
WFI instruction it stops executing instructions and enters sleep mode. See “WFI” on page 151 for more
information.
10.8.1.2 Wait for event
The wait for event instruction, WFE, causes entry to sleep mode conditional on the value of an one-bit event
register. When the processor executes a WFE instruction, it checks this register:
if the register is 0 the processor stops executing instructions and enters sleep mode
if the register is 1 the processor clears the register to 0 and continues executing instructions without entering
sleep mode.
See “WFE” on page 150 for more information.
10.8.1.3 Sleep-on-exit
If the SLEEPONEXIT bit of the SCR is set to 1, when the processor completes the execution of an exception
handler it returns to Thread mode and immediately enters sleep mode. Use this mechanism in applications that
only require the processor to run when an exception occurs.
10.8.2 Wakeup from sleep mode
The conditions for the processor to wakeup depend on the mechanism that cause it to enter sleep mode.
10.8.2.1 Wakeup from WFI or sleep-on-exit
Normally, the processor wakes up only when it detects an exception with sufficient priority to cause exception
entry.
Some embedded systems might have to execute system restore tasks after the processor wakes up, and before it
executes an interrupt handler. To achieve this set the PRIMASK bit to 1 and the FAULTMASK bit to 0. If an
interrupt arrives that is enabled and has a higher priority than current exception priority, the processor wakes up
but does not execute the interrupt handler until the processor sets PRIMASK to zero. For more information about
PRIMASK and FAULTMASK see “Exception mask registers” on page 56.
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10.8.2.2 Wakeup from WFE
The processor wakes up if:
it detects an exception with sufficient priority to cause exception entry
In addition, if the SEVONPEND bit in the SCR is set to 1, any new pending interrupt triggers an event and wakes
up the processor, even if the interrupt is disabled or has insufficient priority to cause exception entry. For more
information about the SCR see “System Control Register” on page 174.
10.8.3 Power management programming hints
ANSI C cannot directly generate the WFI and WFE instructions. The CMSIS provides the following intrinsic
functions for these instructions:
void __WFE(void) // Wait for Event
void __WFE(void) // Wait for Interrupt
10.9 Instruction set summary
The processor implements a version of the Thumb instruction set. Table 10-13 lists the supported instructions.
In Table 10-13:
angle brackets, <>, enclose alternative forms of the operand
braces, {}, enclose optional operands
the Operands column is not exhaustive
Op2 is a flexible second operand that can be either a register or a constant
most instructions can use an optional condition code suffix.
For more information on the instructions and operands, see the instruction descriptions.
Table 10-13. Cortex-M3 instructions
Mnemonic Operands Brief description Flags Page
ADC, ADCS {Rd,} Rn, Op2 Add with Carry N,Z,C,V page 110
ADD, ADDS {Rd,} Rn, Op2 Add N,Z,C,V page 110
ADD, ADDW {Rd,} Rn, #imm12 Add N,Z,C,V page 110
ADR Rd, label Load PC-relative address - page 95
AND, ANDS {Rd,} Rn, Op2 Logical AND N,Z,C page 113
ASR, ASRS Rd, Rm, <Rs|#n> Arithmetic Shift Right N,Z,C page 114
B label Branch - page 134
BFC Rd, #lsb, #width Bit Field Clear - page 130
BFI Rd, Rn, #lsb, #width Bit Field Insert - page 130
BIC, BICS
{Rd,}
Rn, Op2
Bit Clear N,Z,C page 113
BKPT #imm Breakpoint - page 142
BL label Branch with Link - page 134
BLX Rm Branch indirect with Link - page 134
BX Rm Branch indirect - page 134
CBNZ Rn, label Compare and Branch if Non Zero - page 136
CBZ Rn, label Compare and Branch if Zero - page 136
CLREX - Clear Exclusive - page 108
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CLZ Rd, Rm Count leading zeros - page 116
CMN, CMNS Rn, Op2 Compare Negative N,Z,C,V page 117
CMP, CMPS Rn, Op2 Compare N,Z,C,V page 117
CPSID iflags Change Processor State, Disable Interrupts - page 143
CPSIE iflags Change Processor State, Enable Interrupts - page 143
DMB - Data Memory Barrier - page 144
DSB - Data Synchronization Barrier - page 144
EOR, EORS {Rd,} Rn, Op2 Exclusive OR N,Z,C page 113
ISB - Instruction Synchronization Barrier - page 145
IT - If-Then condition block - page 137
LDM Rn{!}, reglist Load Multiple registers, increment after - page 103
LDMDB, LDMEA Rn{!}, reglist Load Multiple registers, decrement before - page 103
LDMFD, LDMIA Rn{!}, reglist Load Multiple registers, increment after - page 103
LDR Rt, [Rn, #offset] Load Register with word - page 98
LDRB, LDRBT Rt, [Rn, #offset] Load Register with byte - page 98
LDRD Rt, Rt2, [Rn, #offset] Load Register with two bytes - page 98
LDREX Rt, [Rn, #offset] Load Register Exclusive - page 98
LDREXB Rt, [Rn] Load Register Exclusive with byte - page 98
LDREXH Rt, [Rn] Load Register Exclusive with halfword - page 98
LDRH, LDRHT Rt, [Rn, #offset] Load Register with halfword - page 98
LDRSB, LDRSBT Rt, [Rn, #offset] Load Register with signed byte - page 98
LDRSH, LDRSHT Rt, [Rn, #offset] Load Register with signed halfword - page 98
LDRT Rt, [Rn, #offset] Load Register with word - page 98
LSL, LSLS Rd, Rm, <Rs|#n> Logical Shift Left N,Z,C page 114
LSR, LSRS Rd, Rm, <Rs|#n> Logical Shift Right N,Z,C page 114
MLA Rd, Rn, Rm, Ra Multiply with Accumulate, 32-bit result - page 124
MLS Rd, Rn, Rm, Ra Multiply and Subtract, 32-bit result - page 124
MOV, MOVS Rd, Op2 Move N,Z,C page 118
MOVT Rd, #imm16 Move Top - page 120
MOVW, MOV Rd, #imm16 Move 16-bit constant N,Z,C page 118
MRS Rd, spec_reg Move from special register to general register - page 146
MSR spec_reg, Rm Move from general register to special register N,Z,C,V page 147
MUL, MULS {Rd,} Rn, Rm Multiply, 32-bit result N,Z page 124
MVN, MVNS Rd, Op2 Move NOT N,Z,C page 118
NOP - No Operation - page 148
ORN, ORNS {Rd,} Rn, Op2 Logical OR NOT N,Z,C page 113
ORR, ORRS {Rd,} Rn, Op2 Logical OR N,Z,C page 113
Table 10-13. Cortex-M3 instructions (Continued)
Mnemonic Operands Brief description Flags Page
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POP reglist Pop registers from stack - page 105
PUSH reglist Push registers onto stack - page 105
RBIT Rd, Rn Reverse Bits - page 121
REV Rd, Rn Reverse byte order in a word - page 121
REV16 Rd, Rn Reverse byte order in each halfword - page 121
REVSH Rd, Rn Reverse byte order in bottom halfword and
sign extend -page 121
ROR, RORS Rd, Rm, <Rs|#n> Rotate Right N,Z,C page 114
RRX, RRXS Rd, Rm Rotate Right with Extend N,Z,C page 114
RSB, RSBS {Rd,} Rn, Op2 Reverse Subtract N,Z,C,V page 110
SBC, SBCS {Rd,} Rn, Op2 Subtract with Carry N,Z,C,V page 110
SBFX Rd, Rn, #lsb, #width Signed Bit Field Extract - page 131
SDIV {Rd,} Rn, Rm Signed Divide - page 126
SEV - Send Event - page 148
SMLAL RdLo, RdHi, Rn, Rm Signed Multiply with Accumulate (32 x 32 +
64), 64-bit result -page 125
SMULL RdLo, RdHi, Rn, Rm Signed Multiply (32 x 32), 64-bit result - page 125
SSAT Rd, #n, Rm {,shift #s} Signed Saturate Q page 127
STM Rn{!}, reglist Store Multiple registers, increment after - page 103
STMDB, STMEA Rn{!}, reglist Store Multiple registers, decrement before - page 103
STMFD, STMIA Rn{!}, reglist Store Multiple registers, increment after - page 103
STR Rt, [Rn, #offset] Store Register word - page 98
STRB, STRBT Rt, [Rn, #offset] Store Register byte - page 98
STRD Rt, Rt2, [Rn, #offset] Store Register two words - page 98
STREX Rd, Rt, [Rn, #offset] Store Register Exclusive - page 106
STREXB Rd, Rt, [Rn] Store Register Exclusive byte - page 106
STREXH Rd, Rt, [Rn] Store Register Exclusive halfword - page 106
STRH, STRHT Rt, [Rn, #offset] Store Register halfword - page 98
STRT Rt, [Rn, #offset] Store Register word - page 98
SUB, SUBS {Rd,} Rn, Op2 Subtract N,Z,C,V page 110
SUB, SUBW {Rd,} Rn, #imm12 Subtract N,Z,C,V page 110
SVC #imm Supervisor Call - page 149
SXTB {Rd,} Rm {,ROR #n} Sign extend a byte - page 132
SXTH {Rd,} Rm {,ROR #n} Sign extend a halfword - page 132
TBB [Rn, Rm] Table Branch Byte - page 139
TBH [Rn, Rm, LSL #1] Table Branch Halfword - page 139
TEQ Rn, Op2 Test Equivalence N,Z,C page 122
TST Rn, Op2 Test N,Z,C page 122
Table 10-13. Cortex-M3 instructions (Continued)
Mnemonic Operands Brief description Flags Page
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UBFX Rd, Rn, #lsb, #width Unsigned Bit Field Extract - page 131
UDIV {Rd,} Rn, Rm Unsigned Divide - page 126
UMLAL RdLo, RdHi, Rn, Rm Unsigned Multiply with Accumulate
(32 x 32 + 64), 64-bit result -page 125
UMULL RdLo, RdHi, Rn, Rm Unsigned Multiply (32 x 32), 64-bit result - page 125
USAT Rd, #n, Rm {,shift #s} Unsigned Saturate Q page 127
UXTB {Rd,} Rm {,ROR #n} Zero extend a byte - page 132
UXTH {Rd,} Rm {,ROR #n} Zero extend a halfword - page 132
WFE - Wait For Event - page 150
WFI - Wait For Interrupt - page 151
Table 10-13. Cortex-M3 instructions (Continued)
Mnemonic Operands Brief description Flags Page
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10.10 Intrinsic functions
ANSI cannot directly access some Cortex-M3 instructions. This section describes intrinsic functions that can
generate these instructions, provided by the CMIS and that might be provided by a C compiler. If a C compiler
does not support an appropriate intrinsic function, you might have to use inline assembler to access some
instructions.
The CMSIS provides the following intrinsic functions to generate instructions that ANSI cannot directly access:
The CMSIS also provides a number of functions for accessing the special registers using MRS and MSR
instructions
Table 10-14. CMSIS intrinsic functions to generate some Cortex-M3 instructions
Instruction CMSIS intrinsic function
CPSIE I void __enable_irq(void)
CPSID I void __disable_irq(void)
CPSIE F void __enable_fault_irq(void)
CPSID F void __disable_fault_irq(void)
ISB void __ISB(void)
DSB void __DSB(void)
DMB void __DMB(void)
REV uint32_t __REV(uint32_t int value)
REV16 uint32_t __REV16(uint32_t int value)
REVSH uint32_t __REVSH(uint32_t int value)
RBIT uint32_t __RBIT(uint32_t int value)
SEV void __SEV(void)
WFE void __WFE(void)
WFI void __WFI(void)
Table 10-15. CMSIS intrinsic functions to access the special registers
Special register Access CMSIS function
PRIMASK Read uint32_t __get_PRIMASK (void)
Write void __set_PRIMASK (uint32_t value)
FAULTMASK Read uint32_t __get_FAULTMASK (void)
Write void __set_FAULTMASK (uint32_t value)
BASEPRI Read uint32_t __get_BASEPRI (void)
Write void __set_BASEPRI (uint32_t value)
CONTROL Read uint32_t __get_CONTROL (void)
Write void __set_CONTROL (uint32_t value)
MSP Read uint32_t __get_MSP (void)
Write void __set_MSP (uint32_t TopOfMainStack)
PSP Read uint32_t __get_PSP (void)
Write void __set_PSP (uint32_t TopOfProcStack)
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10.11 About the instruction descriptions
The following sections give more information about using the instructions:
“Operands” on page 86
“Restrictions when using PC or SP” on page 86
“Flexible second operand” on page 86
“Shift Operations” on page 87
“Address alignment” on page 90
“PC-relative expressions” on page 90
“Conditional execution” on page 91
“Instruction width selection” on page 92.
10.11.1 Operands
An instruction operand can be an ARM register, a constant, or another instruction-specific parameter. Instructions
act on the operands and often store the result in a destination register. When there is a destination register in the
instruction, it is usually specified before the operands.
Operands in some instructions are flexible in that they can either be a register or a constant. See “Flexible second
operand” .
10.11.2 Restrictions when using PC or SP
Many instructions have restrictions on whether you can use the Program Counter (PC) or Stack Pointer (SP) for
the operands or destination register. See instruction descriptions for more information.
Bit[0] of any address you write to the PC with a BX, BLX, LDM, LDR, or POP instruction must be 1 for correct
execution, because this bit indicates the required instruction set, and the Cortex-M3 processor only supports
Thumb instructions.
10.11.3 Flexible second operand
Many general data processing instructions have a flexible second operand. This is shown as Operand2 in the
descriptions of the syntax of each instruction.
Operand2 can be a:
“Constant”
“Register with optional shift” on page 87
10.11.3.1 Constant
You specify an Operand2 constant in the form:
#constant
where constant can be:
any constant that can be produced by shifting an 8-bit value left by any number of bits within a 32-bit word
any constant of the form 0x00XY00XY
any constant of the form 0xXY00XY00
any constant of the form 0xXYXYXYXY.
In the constants shown above, X and Y are hexadecimal digits.
In addition, in a small number of instructions, constant can take a wider range of values. These are described in
the individual instruction descriptions.
When an Operand2 constant is used with the instructions MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS,
TEQ or TST, the carry flag is updated to bit[31] of the constant, if the constant is greater than 255 and can be
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produced by shifting an 8-bit value. These instructions do not affect the carry flag if Operand2 is any other
constant.
10.11.3.2 Instruction substitution
Your assembler might be able to produce an equivalent instruction in cases where you specify a constant that is
not permitted. For example, an assembler might assemble the instruction CMP
Rd
, #0xFFFFFFFE as the
equivalent instruction CMN Rd, #0x2.
10.11.3.3 Register with optional shift
You specify an Operand2 register in the form:
Rm {, shift}
where:
Rm is the register holding the data for the second operand.
shift is an optional shift to be applied to Rm. It can be one of:
ASR #narithmetic shift right n bits, 1 ≤ n ≤ 32.
LSL #nlogical shift left n bits, 1 ≤ n ≤ 31.
LSR #nlogical shift right n bits, 1 ≤ n ≤ 32.
ROR #nrotate right n bits, 1 ≤ n ≤ 31.
RRX rotate right one bit, with extend.
- if omitted, no shift occurs, equivalent to LSL #0.
If you omit the shift, or specify LSL #0, the instruction uses the value in Rm.
If you specify a shift, the shift is applied to the value in Rm, and the resulting 32-bit value is used by the instruction.
However, the contents in the register Rm remains unchanged. Specifying a register with shift also updates the
carry flag when used with certain instructions. For information on the shift operations and how they affect the carry
flag, see “Shift Operations”
10.11.4 Shift Operations
Register shift operations move the bits in a register left or right by a specified number of bits, the shift length.
Register shift can be performed:
directly by the instructions ASR, LSR, LSL, ROR, and RRX, and the result is written to a destination register
during the calculation of Operand2 by the instructions that specify the second operand as a register with
shift, see “Flexible second operand” on page 86. The result is used by the instruction.
The permitted shift lengths depend on the shift type and the instruction, see the individual instruction description or
“Flexible second operand” on page 86. If the shift length is 0, no shift occurs. Register shift operations update the
carry flag except when the specified shift length is 0. The following sub-sections describe the various shift
operations and how they affect the carry flag. In these descriptions, Rm is the register containing the value to be
shifted, and n is the shift length.
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10.11.4.1 ASR
Arithmetic shift right by n bits moves the left-hand 32-n bits of the register Rm, to the right by n places, into the
right-hand 32-n bits of the result. And it copies the original bit[31] of the register into the left-hand n bits of the
result. See Figure 10-4 on page 88.
You can use the ASR #n operation to divide the value in the register Rm by 2n, with the result being rounded
towards negative-infinity.
When the instruction is ASRS or when ASR #n is used in Operand2 with the instructions MOVS, MVNS, ANDS,
ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit shifted out, bit[n-1], of the
register Rm.
If n is 32 or more, then all the bits in the result are set to the value of bit[31] of Rm.
If n is 32 or more and the carry flag is updated, it is updated to the value of bit[31] of Rm.
Figure 10-4. ASR #3
10.11.4.2 LSR
Logical shift right by n bits moves the left-hand 32-n bits of the register Rm, to the right by n places, into the right-
hand 32-n bits of the result. And it sets the left-hand n bits of the result to 0. See Figure 10-5.
You can use the LSR #n operation to divide the value in the register Rm by 2n, if the value is regarded as an
unsigned integer.
When the instruction is LSRS or when LSR #n is used in Operand2 with the instructions MOVS, MVNS, ANDS,
ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit shifted out, bit[n-1], of the
register Rm.
If n is 32 or more, then all the bits in the result are cleared to 0.
If n is 33 or more and the carry flag is updated, it is updated to 0.
Figure 10-5. LSR #3
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10.11.4.3 LSL
Logical shift left by n bits moves the right-hand 32-n bits of the register Rm, to the left by n places, into the left-hand
32-n bits of the result. And it sets the right-hand n bits of the result to 0. See Figure 10-6 on page 89.
You can use he LSL #n operation to multiply the value in the register Rm by 2n, if the value is regarded as an
unsigned integer or a two’s complement signed integer. Overflow can occur without warning.
When the instruction is LSLS or when LSL #n, with non-zero n, is used in Operand2 with the instructions MOVS,
MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit shifted out, bit[32-
n], of the register Rm. These instructions do not affect the carry flag when used with LSL #0.
If n is 32 or more, then all the bits in the result are cleared to 0.
If n is 33 or more and the carry flag is updated, it is updated to 0.
Figure 10-6. LSL #3
10.11.4.4 ROR
Rotate right by n bits moves the left-hand 32-n bits of the register Rm, to the right by n places, into the right-hand
32-n bits of the result. And it moves the right-hand n bits of the register into the left-hand n bits of the result. See
Figure 10-7.
When the instruction is RORS or when ROR #n is used in Operand2 with the instructions MOVS, MVNS, ANDS,
ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit rotation, bit[n-1], of the register
Rm.
If n is 32, then the value of the result is same as the value in Rm, and if the carry flag is updated, it is updated
to bit[31] of Rm.
ROR with shift length, n, more than 32 is the same as ROR with shift length n-32.
Figure 10-7. ROR #3
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10.11.4.5 RRX
Rotate right with extend moves the bits of the register Rm to the right by one bit. And it copies the carry flag into
bit[31] of the result. See Figure 10-8 on page 90.
When the instruction is RRXS or when RRX is used in Operand2 with the instructions MOVS, MVNS, ANDS,
ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to bit[0] of the register Rm.
Figure 10-8. RRX
10.11.5 Address alignment
An aligned access is an operation where a word-aligned address is used for a word, dual word, or multiple word
access, or where a halfword-aligned address is used for a halfword access. Byte accesses are always aligned.
The Cortex-M3 processor supports unaligned access only for the following instructions:
LDR, LDRT
LDRH, LDRHT
LDRSH, LDRSHT
STR, STRT
STRH, STRHT
All other load and store instructions generate a usage fault exception if they perform an unaligned access, and
therefore their accesses must be address aligned. For more information about usage faults see “Fault handling” on
page 78.
Unaligned accesses are usually slower than aligned accesses. In addition, some memory regions might not
support unaligned accesses. Therefore, ARM recommends that programmers ensure that accesses are aligned.
To avoid accidental generation of unaligned accesses, use the UNALIGN_TRP bit in the Configuration and Control
Register to trap all unaligned accesses, see “Configuration and Control Register” on page 175.
10.11.6 PC-relative expressions
A PC-relative expression or label is a symbol that represents the address of an instruction or literal data. It is
represented in the instruction as the PC value plus or minus a numeric offset. The assembler calculates the
required offset from the label and the address of the current instruction. If the offset is too big, the assembler
produces an error.
For B, BL, CBNZ, and CBZ instructions, the value of the PC is the address of the current instruction plus 4
bytes.
For all other instructions that use labels, the value of the PC is the address of the current instruction plus 4
bytes, with bit[1] of the result cleared to 0 to make it word-aligned.
Your assembler might permit other syntaxes for PC-relative expressions, such as a label plus or minus a
number, or an expression of the form [PC, #number].
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10.11.7 Conditional execution
Most data processing instructions can optionally update the condition flags in the Application Program Status
Register (APSR) according to the result of the operation, see “Application Program Status Register” on page 54.
Some instructions update all flags, and some only update a subset. If a flag is not updated, the original value is
preserved. See the instruction descriptions for the flags they affect.
You can execute an instruction conditionally, based on the condition flags set in another instruction, either:
immediately after the instruction that updated the flags
after any number of intervening instructions that have not updated the flags.
Conditional execution is available by using conditional branches or by adding condition code suffixes to
instructions. See Table 10-16 on page 92 for a list of the suffixes to add to instructions to make them conditional
instructions. The condition code suffix enables the processor to test a condition based on the flags. If the condition
test of a conditional instruction fails, the instruction:
does not execute
does not write any value to its destination register
does not affect any of the flags
does not generate any exception.
Conditional instructions, except for conditional branches, must be inside an If-Then instruction block. See “IT” on
page 137 for more information and restrictions when using the IT instruction. Depending on the vendor, the
assembler might automatically insert an IT instruction if you have conditional instructions outside the IT block.
Use the CBZ and CBNZ instructions to compare the value of a register against zero and branch on the result.
This section describes:
“The condition flags”
“Condition code suffixes” .
10.11.7.1 The condition flags
The APSR contains the following condition flags:
N Set to 1 when the result of the operation was negative, cleared to 0 otherwise.
Z Set to 1 when the result of the operation was zero, cleared to 0 otherwise.
C Set to 1 when the operation resulted in a carry, cleared to 0 otherwise.
V Set to 1 when the operation caused overflow, cleared to 0 otherwise.
For more information about the APSR see “Program Status Register” on page 52.
A carry occurs:
if the result of an addition is greater than or equal to 232
if the result of a subtraction is positive or zero
as the result of an inline barrel shifter operation in a move or logical instruction.
Overflow occurs if the result of an add, subtract, or compare is greater than or equal to 231, or less than –231.
Most instructions update the status flags only if the S suffix is specified. See the instruction descriptions for more
information.
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10.11.7.2 Condition code suffixes
The instructions that can be conditional have an optional condition code, shown in syntax descriptions as {cond}.
Conditional execution requires a preceding IT instruction. An instruction with a condition code is only executed if
the condition code flags in the APSR meet the specified condition. Table 10-16 shows the condition codes to use.
You can use conditional execution with the IT instruction to reduce the number of branch instructions in code.
Table 10-16 also shows the relationship between condition code suffixes and the N, Z, C, and V flags.
10.11.7.3 Absolute value
The example below shows the use of a conditional instruction to find the absolute value of a number. R0 = ABS(R1).
MOVS R0, R1 ; R0 = R1, setting flags
IT MI ; IT instruction for the negative condition
RSBMI R0, R1, #0 ; If negative, R0 = -R1
10.11.7.4 Compare and update value
The example below shows the use of conditional instructions to update the value of R4 if the signed values R0 is greater
than R1 and R2 is greater than R3.
CMP R0, R1 ; Compare R0 and R1, setting flags
ITT GT ; IT instruction for the two GT conditions
CMPGT R2, R3 ; If 'greater than', compare R2 and R3, setting flags
MOVGT R4, R5 ; If still 'greater than', do R4 = R5
10.11.8 Instruction width selection
There are many instructions that can generate either a 16-bit encoding or a 32-bit encoding depending on the
operands and destination register specified. For some of these instructions, you can force a specific instruction
size by using an instruction width suffix. The .W suffix forces a 32-bit instruction encoding. The .N suffix forces a
16-bit instruction encoding.
Table 10-16. Condition code suffixes
Suffix Flags Meaning
EQ Z = 1 Equal
NE Z = 0 Not equal
CS or
HS C = 1 Higher or same, unsigned ≥
CC or
LO C = 0 Lower, unsigned <
MI N = 1 Negative
PL N = 0 Positive or zero
VS V = 1 Overflow
VC V = 0 No overflow
HI C = 1 and Z = 0 Higher, unsigned >
LS C = 0 or Z = 1 Lower or same, unsigned ≤
GE N = V Greater than or equal, signed ≥
LT N != V Less than, signed <
GT Z = 0 and N = V Greater than, signed >
LE Z = 1 and N != V Less than or equal, signed ≤
AL Can have any
value Always. This is the default when no suffix is
specified.
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If you specify an instruction width suffix and the assembler cannot generate an instruction encoding of the
requested width, it generates an error.
In some cases it might be necessary to specify the .W suffix, for example if the operand is the label of an
instruction or literal data, as in the case of branch instructions. This is because the assembler might not
automatically generate the right size encoding.
10.11.8.1 Instruction width selection
To use an instruction width suffix, place it immediately after the instruction mnemonic and condition code, if any. The
example below shows instructions with the instruction width suffix.
BCS.W label ; creates a 32-bit instruction even for a short branch
ADDS.W R0, R0, R1 ; creates a 32-bit instruction even though the same
; operation can be done by a 16-bit instruction
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10.12 Memory access instructions
Table 10-17 shows the memory access instructions:
Table 10-17. Memory access instructions
Mnemonic Brief description See
ADR Load PC-relative address “ADR” on page 95
CLREX Clear Exclusive “CLREX” on page 108
LDM{mode} Load Multiple registers “LDM and STM” on page 103
LDR{type} Load Register using immediate offset “LDR and STR, immediate offset” on page 96
LDR{type} Load Register using register offset “LDR and STR, register offset” on page 98
LDR{type}T Load Register with unprivileged access “LDR and STR, unprivileged” on page 100
LDR Load Register using PC-relative address “LDR, PC-relative” on page 101
LDREX{type} Load Register Exclusive “LDREX and STREX” on page 106
POP Pop registers from stack “PUSH and POP” on page 105
PUSH Push registers onto stack “PUSH and POP” on page 105
STM{mode} Store Multiple registers “LDM and STM” on page 103
STR{type} Store Register using immediate offset “LDR and STR, immediate offset” on page 96
STR{type} Store Register using register offset “LDR and STR, register offset” on page 98
STR{type}T Store Register with unprivileged access “LDR and STR, unprivileged” on page 100
STREX{type} Store Register Exclusive “LDREX and STREX” on page 106
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10.12.1 ADR
Load PC-relative address.
10.12.1.1 Syntax
ADR{cond} Rd, label
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register.
label is a PC-relative expression. See “PC-relative expressions” on page 90.
10.12.1.2 Operation
ADR determines the address by adding an immediate value to the PC, and writes the result to the destination
register.
ADR produces position-independent code, because the address is PC-relative.
If you use ADR to generate a target address for a BX or BLX instruction, you must ensure that bit[0] of the address
you generate is set to1 for correct execution.
Values of label must be within the range of −4095 to +4095 from the address in the PC.
You might have to use the .W suffix to get the maximum offset range or to generate addresses that are not word-
aligned. See “Instruction width selection” on page 92.
10.12.1.3 Restrictions
Rd must not be SP and must not be PC.
10.12.1.4 Condition flags
This instruction does not change the flags.
10.12.1.5 Examples
ADR R1, TextMessage ; Write address value of a location labelled as
; TextMessage to R1
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10.12.2 LDR and STR, immediate offset
Load and Store with immediate offset, pre-indexed immediate offset, or post-indexed immediate offset.
10.12.2.1 Syntax
op{type}{cond} Rt, [Rn {, #offset}] ; immediate offset
op{type}{cond} Rt, [Rn, #offset]! ; pre-indexed
op{type}{cond} Rt, [Rn], #offset ; post-indexed
opD{cond} Rt, Rt2, [Rn {, #offset}] ; immediate offset, two words
opD{cond} Rt, Rt2, [Rn, #offset]! ; pre-indexed, two words
opD{cond} Rt, Rt2, [Rn], #offset ; post-indexed, two words
where:
op is one of:
LDR Load Register.
STR Store Register.
type is one of:
B unsigned byte, zero extend to 32 bits on loads.
SB signed byte, sign extend to 32 bits (LDR only).
H unsigned halfword, zero extend to 32 bits on loads.
SH signed halfword, sign extend to 32 bits (LDR only).
- omit, for word.
cond is an optional condition code, see “Conditional execution” on page 91.
Rt is the register to load or store.
Rn is the register on which the memory address is based.
offset is an offset from Rn. If offset is omitted, the address is the contents of Rn.
Rt2 is the additional register to load or store for two-word operations.
10.12.2.2 Operation
LDR instructions load one or two registers with a value from memory.
STR instructions store one or two register values to memory.
Load and store instructions with immediate offset can use the following addressing modes:
10.12.2.3 Offset addressing
The offset value is added to or subtracted from the address obtained from the register Rn. The result is used as the
address for the memory access. The register Rn is unaltered. The assembly language syntax for this mode is:
[Rn, #offset]
10.12.2.4 Pre-indexed addressing
The offset value is added to or subtracted from the address obtained from the register Rn. The result is used as the
address for the memory access and written back into the register Rn. The assembly language syntax for this mode
is:
[Rn, #offset]!
10.12.2.5 Post-indexed addressing
The address obtained from the register Rn is used as the address for the memory access. The offset value is
added to or subtracted from the address, and written back into the register Rn. The assembly language syntax for
this mode is:
[Rn], #offset
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The value to load or store can be a byte, halfword, word, or two words. Bytes and halfwords can either be signed
or unsigned. See “Address alignment” on page 90.
Table 10-18 shows the ranges of offset for immediate, pre-indexed and post-indexed forms.
10.12.2.6 Restrictions
For load instructions:
Rt can be SP or PC for word loads only
Rt must be different from Rt2 for two-word loads
Rn must be different from Rt and Rt2 in the pre-indexed or post-indexed forms.
When Rt is PC in a word load instruction:
bit[0] of the loaded value must be 1 for correct execution
a branch occurs to the address created by changing bit[0] of the loaded value to 0
if the instruction is conditional, it must be the last instruction in the IT block.
For store instructions:
Rt can be SP for word stores only
Rt must not be PC
Rn must not be PC
Rn must be different from Rt and Rt2 in the pre-indexed or post-indexed forms.
10.12.2.7 Condition flags
These instructions do not change the flags.
10.12.2.8 Examples
LDR R8, [R10] ; Loads R8 from the address in R10.
LDRNE R2, [R5, #960]! ; Loads (conditionally) R2 from a word
; 960 bytes above the address in R5, and
; increments R5 by 960.
STR R2, [R9,#const-struc] ; const-struc is an expression evaluating
; to a constant in the range 0-4095.
STRH R3, [R4], #4 ; Store R3 as halfword data into address in
; R4, then increment R4 by 4
LDRD R8, R9, [R3, #0x20] ; Load R8 from a word 32 bytes above the
; address in R3, and load R9 from a word 36
; bytes above the address in R3
STRD R0, R1, [R8], #-16 ; Store R0 to address in R8, and store R1 to
; a word 4 bytes above the address in R8,
; and then decrement R8 by 16.
Table 10-18. Offset ranges
Instruction type Immediate offset Pre-indexed Post-indexed
Word, halfword, signed halfword,
byte, or signed byte −255 to 4095 −255 to 255 −255 to 255
Two words multiple of 4 in the range
−1020 to 1020 multiple of 4 in the range
−1020 to 1020 multiple of 4 in the range
−1020 to 1020
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10.12.3 LDR and STR, register offset
Load and Store with register offset.
10.12.3.1 Syntax
op{type}{cond} Rt, [Rn, Rm {, LSL #n}]
where:
op is one of:
LDR Load Register.
STR Store Register.
type is one of:
B unsigned byte, zero extend to 32 bits on loads.
SB signed byte, sign extend to 32 bits (LDR only).
H unsigned halfword, zero extend to 32 bits on loads.
SH signed halfword, sign extend to 32 bits (LDR only).
- omit, for word.
cond is an optional condition code, see “Conditional execution” on page 91.
Rt is the register to load or store.
Rn is the register on which the memory address is based.
Rm is a register containing a value to be used as the offset.
LSL #nis an optional shift, with n in the range 0 to 3.
10.12.3.2 Operation
LDR instructions load a register with a value from memory.
STR instructions store a register value into memory.
The memory address to load from or store to is at an offset from the register Rn. The offset is specified by the
register Rm and can be shifted left by up to 3 bits using LSL.
The value to load or store can be a byte, halfword, or word. For load instructions, bytes and halfwords can either
be signed or unsigned. See “Address alignment” on page 90.
10.12.3.3 Restrictions
In these instructions:
Rn must not be PC
Rm must not be SP and must not be PC
Rt can be SP only for word loads and word stores
Rt can be PC only for word loads.
When Rt is PC in a word load instruction:
bit[0] of the loaded value must be 1 for correct execution, and a branch occurs to this halfword-aligned
address
if the instruction is conditional, it must be the last instruction in the IT block.
10.12.3.4 Condition flags
These instructions do not change the flags.
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10.12.3.5 Examples
STR R0, [R5, R1] ; Store value of R0 into an address equal to
; sum of R5 and R1
LDRSB R0, [R5, R1, LSL #1] ; Read byte value from an address equal to
; sum of R5 and two times R1, sign extended it
; to a word value and put it in R0
STR R0, [R1, R2, LSL #2] ; Stores R0 to an address equal to sum of R1
; and four times R2
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10.12.4 LDR and STR, unprivileged
Load and Store with unprivileged access.
10.12.4.1 Syntax
op{type}T{cond} Rt, [Rn {, #offset}] ; immediate offset
where:
op is one of:
LDR Load Register.
STR Store Register.
type is one of:
B unsigned byte, zero extend to 32 bits on loads.
SB signed byte, sign extend to 32 bits (LDR only).
H unsigned halfword, zero extend to 32 bits on loads.
SH signed halfword, sign extend to 32 bits (LDR only).
- omit, for word.
cond is an optional condition code, see “Conditional execution” on page 91.
Rt is the register to load or store.
Rn is the register on which the memory address is based.
offset is an offset from Rn and can be 0 to 255.
If offset is omitted, the address is the value in Rn.
10.12.4.2 Operation
These load and store instructions perform the same function as the memory access instructions with immediate
offset, see “LDR and STR, immediate offset” on page 96. The difference is that these instructions have only
unprivileged access even when used in privileged software.
When used in unprivileged software, these instructions behave in exactly the same way as normal memory access
instructions with immediate offset.
10.12.4.3 Restrictions
In these instructions:
Rn must not be PC
Rt must not be SP and must not be PC.
10.12.4.4 Condition flags
These instructions do not change the flags.
10.12.4.5 Examples
STRBTEQ R4, [R7] ; Conditionally store least significant byte in
; R4 to an address in R7, with unprivileged access
LDRHT R2, [R2, #8] ; Load halfword value from an address equal to
; sum of R2 and 8 into R2, with unprivileged access
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10.12.5 LDR, PC-relative
Load register from memory.
10.12.5.1 Syntax
LDR{type}{cond} Rt, label
LDRD{cond} Rt, Rt2, label ; Load two words
where:
type is one of:
B unsigned byte, zero extend to 32 bits.
SB signed byte, sign extend to 32 bits.
H unsigned halfword, zero extend to 32 bits.
SH signed halfword, sign extend to 32 bits.
- omit, for word.
cond is an optional condition code, see “Conditional execution” on page 91.
Rt is the register to load or store.
Rt2 is the second register to load or store.
label is a PC-relative expression. See “PC-relative expressions” on page 90.
10.12.5.2 Operation
LDR loads a register with a value from a PC-relative memory address. The memory address is specified by a label
or by an offset from the PC.
The value to load or store can be a byte, halfword, or word. For load instructions, bytes and halfwords can either
be signed or unsigned. See “Address alignment” on page 90.
label must be within a limited range of the current instruction. Table 10-19 shows the possible offsets between
label and the PC.
You might have to use the .W suffix to get the maximum offset range. See “Instruction width selection” on page 92.
10.12.5.3 Restrictions
In these instructions:
Rt can be SP or PC only for word loads
Rt2 must not be SP and must not be PC
Rt must be different from Rt2.
When Rt is PC in a word load instruction:
bit[0] of the loaded value must be 1 for correct execution, and a branch occurs to this halfword-aligned
address
if the instruction is conditional, it must be the last instruction in the IT block.
10.12.5.4 Condition flags
These instructions do not change the flags.
Table 10-19. Offset ranges
Instruction type Offset range
Word, halfword, signed halfword, byte, signed
byte −4095 to 4095
Two words −1020 to 1020
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10.12.5.5 Examples
LDR R0, LookUpTable ; Load R0 with a word of data from an address
; labelled as LookUpTable
LDRSB R7, localdata ; Load a byte value from an address labelled
; as localdata, sign extend it to a word
; value, and put it in R7
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10.12.6 LDM and STM
Load and Store Multiple registers.
10.12.6.1 Syntax
op{addr_mode}{cond} Rn{!}, reglist
where:
op is one of:
LDM Load Multiple registers.
STM Store Multiple registers.
addr_mode is any one of the following:
IA Increment address After each access. This is the default.
DB Decrement address Before each access.
cond is an optional condition code, see “Conditional execution” on page 91.
Rn is the register on which the memory addresses are based.
! is an optional writeback suffix.
If ! is present the final address, that is loaded from or stored to, is written back into Rn.
reglist is a list of one or more registers to be loaded or stored, enclosed in braces. It can contain register
ranges. It must be comma separated if it contains more than one register or register range, see “Examples” on
page 104.
LDM and LDMFD are synonyms for LDMIA. LDMFD refers to its use for popping data from Full Descending
stacks.
LDMEA is a synonym for LDMDB, and refers to its use for popping data from Empty Ascending stacks.
STM and STMEA are synonyms for STMIA. STMEA refers to its use for pushing data onto Empty Ascending
stacks.
STMFD is s synonym for STMDB, and refers to its use for pushing data onto Full Descending stacks
10.12.6.2 Operation
LDM instructions load the registers in reglist with word values from memory addresses based on Rn.
STM instructions store the word values in the registers in reglist to memory addresses based on Rn.
For LDM, LDMIA, LDMFD, STM, STMIA, and STMEA the memory addresses used for the accesses are at 4-byte
intervals ranging from Rn to Rn + 4 * (n-1), where n is the number of registers in reglist. The accesses happens in
order of increasing register numbers, with the lowest numbered register using the lowest memory address and the
highest number register using the highest memory address. If the writeback suffix is specified, the value of Rn + 4
* (n-1) is written back to Rn.
For LDMDB, LDMEA, STMDB, and STMFD the memory addresses used for the accesses are at 4-byte intervals
ranging from Rn to Rn - 4 * (n-1), where n is the number of registers in reglist. The accesses happen in order of
decreasing register numbers, with the highest numbered register using the highest memory address and the
lowest number register using the lowest memory address. If the writeback suffix is specified, the value of Rn - 4 *
(n-1) is written back to Rn.
The PUSH and POP instructions can be expressed in this form. See “PUSH and POP” on page 105 for details.
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10.12.6.3 Restrictions
In these instructions:
Rn must not be PC
reglist must not contain SP
in any STM instruction, reglist must not contain PC
in any LDM instruction, reglist must not contain PC if it contains LR
reglist must not contain Rn if you specify the writeback suffix.
When PC is in reglist in an LDM instruction:
bit[0] of the value loaded to the PC must be 1 for correct execution, and a branch occurs to this halfword-
aligned address
if the instruction is conditional, it must be the last instruction in the IT block.
10.12.6.4 Condition flags
These instructions do not change the flags.
10.12.6.5 Examples
LDM R8,{R0,R2,R9} ; LDMIA is a synonym for LDM
STMDB R1!,{R3-R6,R11,R12}
10.12.6.6 Incorrect examples
STM R5!,{R5,R4,R9} ; Value stored for R5 is unpredictable
LDM R2, {} ; There must be at least one register in the list
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10.12.7 PUSH and POP
Push registers onto, and pop registers off a full-descending stack.
10.12.7.1 Syntax
PUSH{cond} reglist
POP{cond} reglist
where:
cond is an optional condition code, see “Conditional execution” on page 91.
reglist is a non-empty list of registers, enclosed in braces. It can contain register ranges. It must be comma
separated if it contains more than one register or register range.
PUSH and POP are synonyms for STMDB and LDM (or LDMIA) with the memory addresses for the access based
on SP, and with the final address for the access written back to the SP. PUSH and POP are the preferred
mnemonics in these cases.
10.12.7.2 Operation
PUSH stores registers on the stack in order of decreasing the register numbers, with the highest numbered
register using the highest memory address and the lowest numbered register using the lowest memory address.
POP loads registers from the stack in order of increasing register numbers, with the lowest numbered register
using the lowest memory address and the highest numbered register using the highest memory address.
See “LDM and STM” on page 103 for more information.
10.12.7.3 Restrictions
In these instructions:
reglist must not contain SP
for the PUSH instruction, reglist must not contain PC
for the POP instruction, reglist must not contain PC if it contains LR.
When PC is in reglist in a POP instruction:
bit[0] of the value loaded to the PC must be 1 for correct execution, and a branch occurs to this halfword-
aligned address
if the instruction is conditional, it must be the last instruction in the IT block.
10.12.7.4 Condition flags
These instructions do not change the flags.
10.12.7.5 Examples
PUSH {R0,R4-R7}
PUSH {R2,LR}
POP {R0,R10,PC}
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10.12.8 LDREX and STREX
Load and Store Register Exclusive.
10.12.8.1 Syntax
LDREX{cond} Rt, [Rn {, #offset}]
STREX{cond} Rd, Rt, [Rn {, #offset}]
LDREXB{cond} Rt, [Rn]
STREXB{cond} Rd, Rt, [Rn]
LDREXH{cond} Rt, [Rn]
STREXH{cond} Rd, Rt, [Rn]
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register for the returned status.
Rt is the register to load or store.
Rn is the register on which the memory address is based.
offset is an optional offset applied to the value in Rn.
If offset is omitted, the address is the value in Rn.
10.12.8.2 Operation
LDREX, LDREXB, and LDREXH load a word, byte, and halfword respectively from a memory address.
STREX, STREXB, and STREXH attempt to store a word, byte, and halfword respectively to a memory address.
The address used in any Store-Exclusive instruction must be the same as the address in the most recently
executed Load-exclusive instruction. The value stored by the Store-Exclusive instruction must also have the same
data size as the value loaded by the preceding Load-exclusive instruction. This means software must always use a
Load-exclusive instruction and a matching Store-Exclusive instruction to perform a synchronization operation, see
“Synchronization primitives” on page 69
If an Store-Exclusive instruction performs the store, it writes 0 to its destination register. If it does not perform the
store, it writes 1 to its destination register. If the Store-Exclusive instruction writes 0 to the destination register, it is
guaranteed that no other process in the system has accessed the memory location between the Load-exclusive
and Store-Exclusive instructions.
For reasons of performance, keep the number of instructions between corresponding Load-Exclusive and Store-
Exclusive instruction to a minimum.
The result of executing a Store-Exclusive instruction to an address that is different from that used in the preceding
Load-Exclusive instruction is unpredictable.
10.12.8.3 Restrictions
In these instructions:
do not use PC
do not use SP for Rd and Rt
for STREX, Rd must be different from both Rt and Rn
the value of offset must be a multiple of four in the range 0-1020.
10.12.8.4 Condition flags
These instructions do not change the flags.
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10.12.8.5 Examples
MOV R1, #0x1 ; Initialize the ‘lock taken’ value
try
LDREX R0, [LockAddr] ; Load the lock value
CMP R0, #0 ; Is the lock free?
ITT EQ ; IT instruction for STREXEQ and CMPEQ
STREXEQ R0, R1, [LockAddr] ; Try and claim the lock
CMPEQ R0, #0 ; Did this succeed?
BNE try ; No – try again
.... ; Yes – we have the lock
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10.12.9 CLREX
Clear Exclusive.
10.12.9.1 Syntax
CLREX{cond}
where:
cond is an optional condition code, see “Conditional execution” on page 91.
10.12.9.2 Operation
Use CLREX to make the next STREX, STREXB, or STREXH instruction write 1 to its destination register and fail to
perform the store. It is useful in exception handler code to force the failure of the store exclusive if the exception
occurs between a load exclusive instruction and the matching store exclusive instruction in a synchronization
operation.
See “Synchronization primitives” on page 69 for more information.
10.12.9.3 Condition flags
These instructions do not change the flags.
10.12.9.4 Examples
CLREX
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10.13 General data processing instructions
Table 10-20 shows the data processing instructions:
Table 10-20. Data processing instructions
Mnemonic Brief description See
ADC Add with Carry “ADD, ADC, SUB, SBC, and RSB” on page 110
ADD Add “ADD, ADC, SUB, SBC, and RSB” on page 110
ADDW Add “ADD, ADC, SUB, SBC, and RSB” on page 110
AND Logical AND “AND, ORR, EOR, BIC, and ORN” on page 113
ASR Arithmetic Shift Right “ASR, LSL, LSR, ROR, and RRX” on page 114
BIC Bit Clear “AND, ORR, EOR, BIC, and ORN” on page 113
CLZ Count leading zeros “CLZ” on page 116
CMN Compare Negative “CMP and CMN” on page 117
CMP Compare “CMP and CMN” on page 117
EOR Exclusive OR “AND, ORR, EOR, BIC, and ORN” on page 113
LSL Logical Shift Left “ASR, LSL, LSR, ROR, and RRX” on page 114
LSR Logical Shift Right “ASR, LSL, LSR, ROR, and RRX” on page 114
MOV Move “MOV and MVN” on page 118
MOVT Move Top “MOVT” on page 120
MOVW Move 16-bit constant “MOV and MVN” on page 118
MVN Move NOT “MOV and MVN” on page 118
ORN Logical OR NOT “AND, ORR, EOR, BIC, and ORN” on page 113
ORR Logical OR “AND, ORR, EOR, BIC, and ORN” on page 113
RBIT Reverse Bits “REV, REV16, REVSH, and RBIT” on page 121
REV Reverse byte order in a word “REV, REV16, REVSH, and RBIT” on page 121
REV16 Reverse byte order in each halfword “REV, REV16, REVSH, and RBIT” on page 121
REVSH Reverse byte order in bottom halfword and sign extend “REV, REV16, REVSH, and RBIT” on page 121
ROR Rotate Right “ASR, LSL, LSR, ROR, and RRX” on page 114
RRX Rotate Right with Extend “ASR, LSL, LSR, ROR, and RRX” on page 114
RSB Reverse Subtract “ADD, ADC, SUB, SBC, and RSB” on page 110
SBC Subtract with Carry “ADD, ADC, SUB, SBC, and RSB” on page 110
SUB Subtract “ADD, ADC, SUB, SBC, and RSB” on page 110
SUBW Subtract “ADD, ADC, SUB, SBC, and RSB” on page 110
TEQ Test Equivalence “TST and TEQ” on page 122
TST Test “TST and TEQ” on page 122
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10.13.1 ADD, ADC, SUB, SBC, and RSB
Add, Add with carry, Subtract, Subtract with carry, and Reverse Subtract.
10.13.1.1 Syntax
op{S}{cond} {Rd,} Rn, Operand2
op{cond} {Rd,} Rn, #imm12 ; ADD and SUB only
where:
op is one of:
ADD Add.
ADC Add with Carry.
SUB Subtract.
SBC Subtract with Carry.
RSB Reverse Subtract.
S is an optional suffix. If S is specified, the condition code flags are updated on the result of the
operation, see “Conditional execution” on page 91.
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register. If Rd is omitted, the destination register is Rn.
Rn is the register holding the first operand.
Operand2 is a flexible second operand.
See “Flexible second operand” on page 86 for details of the options.
imm12 is any value in the range 0-4095.
10.13.1.2 Operation
The ADD instruction adds the value of Operand2 or imm12 to the value in Rn.
The ADC instruction adds the values in Rn and Operand2, together with the carry flag.
The SUB instruction subtracts the value of Operand2 or imm12 from the value in Rn.
The SBC instruction subtracts the value of Operand2 from the value in Rn. If the carry flag is clear, the result is
reduced by one.
The RSB instruction subtracts the value in Rn from the value of Operand2. This is useful because of the wide
range of options for Operand2.
Use ADC and SBC to synthesize multiword arithmetic, see “Multiword arithmetic examples” on page 112.
See also “ADR” on page 95.
ADDW is equivalent to the ADD syntax that uses the imm12 operand. SUBW is equivalent to the SUB syntax that
uses the imm12 operand.
10.13.1.3 Restrictions
In these instructions:
Operand2 must not be SP and must not be PC
Rd can be SP only in ADD and SUB, and only with the additional restrictions:
̶Rn must also be SP
̶any shift in Operand2 must be limited to a maximum of 3 bits using LSL
Rn can be SP only in ADD and SUB
Rd can be PC only in the ADD{cond} PC, PC, Rm instruction where:
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̶you must not specify the S suffix
̶Rm must not be PC and must not be SP
̶if the instruction is conditional, it must be the last instruction in the IT block
with the exception of the ADD{cond} PC, PC, Rm instruction, Rn can be PC only in ADD and SUB, and only
with the additional restrictions:
̶you must not specify the S suffix
̶the second operand must be a constant in the range 0 to 4095.
̶
̶When using the PC for an addition or a subtraction, bits[1:0] of the PC are rounded to b00 before
performing the calculation, making the base address for the calculation word-aligned.
̶If you want to generate the address of an instruction, you have to adjust the constant based on the
value of the PC. ARM recommends that you use the ADR instruction instead of ADD or SUB with Rn
equal to the PC, because your assembler automatically calculates the correct constant for the ADR
instruction.
When Rd is PC in the ADD{cond} PC, PC, Rm instruction:
bit[0] of the value written to the PC is ignored
a branch occurs to the address created by forcing bit[0] of that value to 0.
10.13.1.4 Condition flags
If S is specified, these instructions update the N, Z, C and V flags according to the result.
10.13.1.5 Examples
ADD R2, R1, R3
SUBS R8, R6, #240 ; Sets the flags on the result
RSB R4, R4, #1280 ; Subtracts contents of R4 from 1280
ADCHI R11, R0, R3 ; Only executed if C flag set and Z
; flag clear
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10.13.1.6 Multiword arithmetic examples
10.13.1.7 64-bit addition
The example below shows two instructions that add a 64-bit integer contained in R2 and R3 to another 64-bit integer con-
tained in R0 and R1, and place the result in R4 and R5.
ADDS R4, R0, R2 ; add the least significant words
ADC R5, R1, R3 ; add the most significant words with carry
10.13.1.8 96-bit subtraction
Multiword values do not have to use consecutive registers. The example below shows instructions that subtract a 96-bit
integer contained in R9, R1, and R11 from another contained in R6, R2, and R8. The example stores the result in R6, R9,
and R2.
SUBS R6, R6, R9 ; subtract the least significant words
SBCS R9, R2, R1 ; subtract the middle words with carry
SBC R2, R8, R11 ; subtract the most significant words with carry
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10.13.2 AND, ORR, EOR, BIC, and ORN
Logical AND, OR, Exclusive OR, Bit Clear, and OR NOT.
10.13.2.1 Syntax
op{S}{cond} {Rd,} Rn, Operand2
where:
op is one of:
AND logical AND.
ORR logical OR, or bit set.
EOR logical Exclusive OR.
BIC logical AND NOT, or bit clear.
ORN logical OR NOT.
S is an optional suffix. If S is specified, the condition code flags are updated on the result of the
operation, see “Conditional execution” on page 91.
cond is an optional condition code, see See “Conditional execution” on page 91..
Rd is the destination register.
Rn is the register holding the first operand.
Operand2 is a flexible second operand. See “Flexible second operand” on page 86 for details of the options.
10.13.2.2 Operation
The AND, EOR, and ORR instructions perform bitwise AND, Exclusive OR, and OR operations on the values in Rn
and Operand2.
The BIC instruction performs an AND operation on the bits in Rn with the complements of the corresponding bits in
the value of Operand2.
The ORN instruction performs an OR operation on the bits in Rn with the complements of the corresponding bits in
the value of Operand2.
10.13.2.3 Restrictions
Do not use SP and do not use PC.
10.13.2.4 Condition flags
If S is specified, these instructions:
update the N and Z flags according to the result
can update the C flag during the calculation of Operand2, see “Flexible second operand” on page 86
do not affect the V flag.
10.13.2.5 Examples
AND R9, R2, #0xFF00
ORREQ R2, R0, R5
ANDS R9, R8, #0x19
EORS R7, R11, #0x18181818
BIC R0, R1, #0xab
ORN R7, R11, R14, ROR #4
ORNS R7, R11, R14, ASR #32
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10.13.3 ASR, LSL, LSR, ROR, and RRX
Arithmetic Shift Right, Logical Shift Left, Logical Shift Right, Rotate Right, and Rotate Right with Extend.
10.13.3.1 Syntax
op{S}{cond} Rd, Rm, Rs
op{S}{cond} Rd, Rm, #n
RRX{S}{cond} Rd, Rm
where:
op is one of:
ASR Arithmetic Shift Right.
LSL Logical Shift Left.
LSR Logical Shift Right.
ROR Rotate Right.
S is an optional suffix. If S is specified, the condition code flags are updated on the result of the
operation, see “Conditional execution” on page 91.
Rd is the destination register.
Rm is the register holding the value to be shifted.
Rs is the register holding the shift length to apply to the value in Rm. Only the least significant byte is
used and can be in the range 0 to 255.
n is the shift length. The range of shift length depends on the instruction:
ASR shift length from 1 to 32
LSL shift length from 0 to 31
LSR shift length from 1 to 32
ROR shift length from 1 to 31.
MOV{S}{cond} Rd, Rm is the preferred syntax for LSL{S}{cond} Rd, Rm, #0.
10.13.3.2 Operation
ASR, LSL, LSR, and ROR move the bits in the register Rm to the left or right by the number of places specified by
constant n or register Rs.
RRX moves the bits in register Rm to the right by 1.
In all these instructions, the result is written to Rd, but the value in register Rm remains unchanged. For details on
what result is generated by the different instructions, see “Shift Operations” on page 87.
10.13.3.3 Restrictions
Do not use SP and do not use PC.
10.13.3.4 Condition flags
If S is specified:
these instructions update the N and Z flags according to the result
the C flag is updated to the last bit shifted out, except when the shift length is 0, see “Shift Operations” on
page 87.
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10.13.3.5 Examples
ASR R7, R8, #9 ; Arithmetic shift right by 9 bits
LSLS R1, R2, #3 ; Logical shift left by 3 bits with flag update
LSR R4, R5, #6 ; Logical shift right by 6 bits
ROR R4, R5, R6 ; Rotate right by the value in the bottom byte of R6
RRX R4, R5 ; Rotate right with extend
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10.13.4 CLZ
Count Leading Zeros.
10.13.4.1 Syntax
CLZ{cond} Rd, Rm
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register.
Rm is the operand register.
10.13.4.2 Operation
The CLZ instruction counts the number of leading zeros in the value in Rm and returns the result in Rd. The result
value is 32 if no bits are set in the source register, and zero if bit[31] is set.
10.13.4.3 Restrictions
Do not use SP and do not use PC.
10.13.4.4 Condition flags
This instruction does not change the flags.
10.13.4.5 Examples
CLZ R4,R9
CLZNE R2,R3
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10.13.5 CMP and CMN
Compare and Compare Negative.
10.13.5.1 Syntax
CMP{cond} Rn, Operand2
CMN{cond} Rn, Operand2
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rn is the register holding the first operand.
Operand2 is a flexible second operand. See “Flexible second operand” on page 86 for details of the options.
10.13.5.2 Operation
These instructions compare the value in a register with Operand2. They update the condition flags on the result,
but do not write the result to a register.
The CMP instruction subtracts the value of Operand2 from the value in Rn. This is the same as a SUBS
instruction, except that the result is discarded.
The CMN instruction adds the value of Operand2 to the value in Rn. This is the same as an ADDS instruction,
except that the result is discarded.
10.13.5.3 Restrictions
In these instructions:
do not use PC
Operand2 must not be SP.
10.13.5.4 Condition flags
These instructions update the N, Z, C and V flags according to the result.
10.13.5.5 Examples
CMP R2, R9
CMN R0, #6400
CMPGT SP, R7, LSL #2
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10.13.6 MOV and MVN
Move and Move NOT.
10.13.6.1 Syntax
MOV{S}{cond} Rd, Operand2
MOV{cond} Rd, #imm16
MVN{S}{cond} Rd, Operand2
where:
S is an optional suffix. If S is specified, the condition code flags are updated on the result of the
operation, see “Conditional execution” on page 91.
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register.
Operand2 is a flexible second operand. See “Flexible second operand” on page 86 for details of the options.
imm16 is any value in the range 0-65535.
10.13.6.2 Operation
The MOV instruction copies the value of Operand2 into Rd.
When Operand2 in a MOV instruction is a register with a shift other than LSL #0, the preferred syntax is the
corresponding shift instruction:
ASR{S}{cond} Rd, Rm, #n is the preferred syntax for MOV{S}{cond} Rd, Rm, ASR #n
LSL{S}{cond} Rd, Rm, #n is the preferred syntax for MOV{S}{cond} Rd, Rm, LSL #n if n!= 0
LSR{S}{cond} Rd, Rm, #n is the preferred syntax for MOV{S}{cond} Rd, Rm, LSR #n
ROR{S}{cond} Rd, Rm, #n is the preferred syntax for MOV{S}{cond} Rd, Rm, ROR #n
RRX{S}{cond} Rd, Rm is the preferred syntax for MOV{S}{cond} Rd, Rm, RRX.
Also, the MOV instruction permits additional forms of Operand2 as synonyms for shift instructions:
MOV{S}{cond} Rd, Rm, ASR Rs is a synonym for ASR{S}{cond} Rd, Rm, Rs
MOV{S}{cond} Rd, Rm, LSL Rs is a synonym for LSL{S}{cond} Rd, Rm, Rs
MOV{S}{cond} Rd, Rm, LSR Rs is a synonym for LSR{S}{cond} Rd, Rm, Rs
MOV{S}{cond} Rd, Rm, ROR Rs is a synonym for ROR{S}{cond} Rd, Rm, Rs
See “ASR, LSL, LSR, ROR, and RRX” on page 114.
The MVN instruction takes the value of Operand2, performs a bitwise logical NOT operation on the value, and
places the result into Rd.
The MOVW instruction provides the same function as MOV, but is restricted to using the imm16 operand.
10.13.6.3 Restrictions
You can use SP and PC only in the MOV instruction, with the following restrictions:
the second operand must be a register without shift
you must not specify the S suffix.
When Rd is PC in a MOV instruction:
bit[0] of the value written to the PC is ignored
a branch occurs to the address created by forcing bit[0] of that value to 0.
Though it is possible to use MOV as a branch instruction, ARM strongly recommends the use of a BX or BLX
instruction to branch for software portability to the ARM instruction set.
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10.13.6.4 Condition flags
If S is specified, these instructions:
update the N and Z flags according to the result
can update the C flag during the calculation of Operand2, see “Flexible second operand” on page 86
do not affect the V flag.
10.13.6.5 Example
MOVS R11, #0x000B ; Write value of 0x000B to R11, flags get updated
MOV R1, #0xFA05 ; Write value of 0xFA05 to R1, flags are not updated
MOVS R10, R12 ; Write value in R12 to R10, flags get updated
MOV R3, #23 ; Write value of 23 to R3
MOV R8, SP ; Write value of stack pointer to R8
MVNS R2, #0xF ; Write value of 0xFFFFFFF0 (bitwise inverse of 0xF)
; to the R2 and update flags
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10.13.7 MOVT
Move Top.
10.13.7.1 Syntax
MOVT{cond} Rd, #imm16
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register.
imm16 is a 16-bit immediate constant.
10.13.7.2 Operation
MOVT writes a 16-bit immediate value, imm16, to the top halfword, Rd[31:16], of its destination register. The write
does not affect Rd[15:0].
The MOV, MOVT instruction pair enables you to generate any 32-bit constant.
10.13.7.3 Restrictions
Rd must not be SP and must not be PC.
10.13.7.4 Condition flags
This instruction does not change the flags.
10.13.7.5 Examples
MOVT R3, #0xF123 ; Write 0xF123 to upper halfword of R3, lower halfword
; and APSR are unchanged
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10.13.8 REV, REV16, REVSH, and RBIT
Reverse bytes and Reverse bits.
10.13.8.1 Syntax
op{cond} Rd, Rn
where:
op is any of:
REV
Reverse byte order in a word.
REV16
Reverse byte order in each halfword independently.
REVSH
Reverse byte order in the bottom halfword, and sign extend to 32 bits.
RBIT
Reverse the bit order in a 32-bit word.
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register.
Rn is the register holding the operand.
10.13.8.2 Operation
Use these instructions to change endianness of data:
REV
converts 32-bit big-endian data into little-endian data or 32-bit little-endian data into big-endian data.
REV16
converts 16-bit big-endian data into little-endian data or 16-bit little-endian data into big-endian data.
REVSH
converts either:
16-bit signed big-endian data into 32-bit signed little-endian data
16-bit signed little-endian data into 32-bit signed big-endian data.
10.13.8.3 Restrictions
Do not use SP and do not use PC
.
10.13.8.4 Condition flags
These instructions do not change the flags.
10.13.8.5 Examples
REV R3, R7 ; Reverse byte order of value in R7 and write it to R3
REV16 R0, R0 ; Reverse byte order of each 16-bit halfword in R0
REVSH R0, R5 ; Reverse Signed Halfword
REVHS R3, R7 ; Reverse with Higher or Same condition
RBIT R7, R8 ; Reverse bit order of value in R8 and write the result to R7
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10.13.9 TST and TEQ
Test bits and Test Equivalence.
10.13.9.1 Syntax
TST{cond} Rn, Operand2
TEQ{cond} Rn, Operand2
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rn is the register holding the first operand.
Operand2 is a flexible second operand. See “Flexible second operand” on page 86 for details of the options.
10.13.9.2 Operation
These instructions test the value in a register against Operand2. They update the condition flags based on the
result, but do not write the result to a register.
The TST instruction performs a bitwise AND operation on the value in Rn and the value of Operand2. This is the
same as the ANDS instruction, except that it discards the result.
To test whether a bit of Rn is 0 or 1, use the TST instruction with an Operand2 constant that has that bit set to 1
and all other bits cleared to 0.
The TEQ instruction performs a bitwise Exclusive OR operation on the value in Rn and the value of Operand2.
This is the same as the EORS instruction, except that it discards the result.
Use the TEQ instruction to test if two values are equal without affecting the V or C flags.
TEQ is also useful for testing the sign of a value. After the comparison, the N flag is the logical Exclusive OR of the
sign bits of the two operands.
10.13.9.3 Restrictions
Do not use SP and do not use PC
.
10.13.9.4 Condition flags
These instructions:
update the N and Z flags according to the result
can update the C flag during the calculation of Operand2, see “Flexible second operand” on page 86
do not affect the V flag.
10.13.9.5 Examples
TST R0, #0x3F8 ; Perform bitwise AND of R0 value to 0x3F8,
; APSR is updated but result is discarded
TEQEQ R10, R9 ; Conditionally test if value in R10 is equal to
; value in R9, APSR is updated but result is discarded
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10.14 Multiply and divide instructions
Table 10-21 shows the multiply and divide instructions:
Table 10-21. Multiply and divide instructions
Mnemonic Brief description See
MLA Multiply with Accumulate, 32-bit result “MUL, MLA, and MLS” on page 124
MLS Multiply and Subtract, 32-bit result “MUL, MLA, and MLS” on page 124
MUL Multiply, 32-bit result “MUL, MLA, and MLS” on page 124
SDIV Signed Divide “SDIV and UDIV” on page 126
SMLAL Signed Multiply with Accumulate (32x32+64), 64-bit result “UMULL, UMLAL, SMULL, and SMLAL” on page 125
SMULL Signed Multiply (32x32), 64-bit result “UMULL, UMLAL, SMULL, and SMLAL” on page 125
UDIV Unsigned Divide “SDIV and UDIV” on page 126
UMLAL Unsigned Multiply with Accumulate (32x32+64), 64-bit result “UMULL, UMLAL, SMULL, and SMLAL” on page 125
UMULL Unsigned Multiply (32x32), 64-bit result “UMULL, UMLAL, SMULL, and SMLAL” on page 125
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10.14.1 MUL, MLA, and MLS
Multiply, Multiply with Accumulate, and Multiply with Subtract, using 32-bit operands, and producing a 32-bit result.
10.14.1.1 Syntax
MUL{S}{cond} {Rd,} Rn, Rm ; Multiply
MLA{cond} Rd, Rn, Rm, Ra ; Multiply with accumulate
MLS{cond} Rd, Rn, Rm, Ra ; Multiply with subtract
where:
cond is an optional condition code, see “Conditional execution” on page 91.
S is an optional suffix. If S is specified, the condition code flags are updated on the result of the
operation, see “Conditional execution” on page 91.
Rd is the destination register. If Rd is omitted, the destination register is Rn.
Rn, Rm are registers holding the values to be multiplied.
Ra is a register holding the value to be added or subtracted from.
10.14.1.2 Operation
The MUL instruction multiplies the values from Rn and Rm, and places the least significant 32 bits of the result in
Rd.
The MLA instruction multiplies the values from Rn and Rm, adds the value from Ra, and places the least
significant 32 bits of the result in Rd.
The MLS instruction multiplies the values from Rn and Rm, subtracts the product from the value from Ra, and
places the least significant 32 bits of the result in Rd.
The results of these instructions do not depend on whether the operands are signed or unsigned.
10.14.1.3 Restrictions
In these instructions, do not use SP and do not use PC.
If you use the S suffix with the MUL instruction:
Rd, Rn, and Rm must all be in the range R0 to R7
Rd must be the same as Rm
you must not use the cond suffix.
10.14.1.4 Condition flags
If S is specified, the MUL instruction:
updates the N and Z flags according to the result
does not affect the C and V flags.
10.14.1.5 Examples
MUL R10, R2, R5 ; Multiply, R10 = R2 x R5
MLA R10, R2, R1, R5 ; Multiply with accumulate, R10 = (R2 x R1) + R5
MULS R0, R2, R2 ; Multiply with flag update, R0 = R2 x R2
MULLT R2, R3, R2 ; Conditionally multiply, R2 = R3 x R2
MLS R4, R5, R6, R7 ; Multiply with subtract, R4 = R7 - (R5 x R6)
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10.14.2 UMULL, UMLAL, SMULL, and SMLAL
Signed and Unsigned Long Multiply, with optional Accumulate, using 32-bit operands and producing a 64-bit
result.
10.14.2.1 Syntax
op{cond} RdLo, RdHi, Rn, Rm
where:
op is one of:
UMULL Unsigned Long Multiply.
UMLAL Unsigned Long Multiply, with Accumulate.
SMULL Signed Long Multiply.
SMLAL Signed Long Multiply, with Accumulate.
cond is an optional condition code, see “Conditional execution” on page 91.
RdHi, RdLo are the destination registers.
For UMLAL and SMLAL they also hold the accumulating value.
Rn, Rm are registers holding the operands.
10.14.2.2 Operation
The UMULL instruction interprets the values from Rn and Rm as unsigned integers. It multiplies these integers and
places the least significant 32 bits of the result in RdLo, and the most significant 32 bits of the result in RdHi.
The UMLAL instruction interprets the values from Rn and Rm as unsigned integers. It multiplies these integers,
adds the 64-bit result to the 64-bit unsigned integer contained in RdHi and RdLo, and writes the result back to
RdHi and RdLo.
The SMULL instruction interprets the values from Rn and Rm as two’s complement signed integers. It multiplies
these integers and places the least significant 32 bits of the result in RdLo, and the most significant 32 bits of the
result in RdHi.
The SMLAL instruction interprets the values from Rn and Rm as two’s complement signed integers. It multiplies
these integers, adds the 64-bit result to the 64-bit signed integer contained in RdHi and RdLo, and writes the result
back to RdHi and RdLo.
10.14.2.3 Restrictions
In these instructions:
do not use SP and do not use PC
RdHi and RdLo must be different registers.
10.14.2.4 Condition flags
These instructions do not affect the condition code flags.
10.14.2.5 Examples
UMULL R0, R4, R5, R6 ; Unsigned (R4,R0) = R5 x R6
SMLAL R4, R5, R3, R8 ; Signed (R5,R4) = (R5,R4) + R3 x R8
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10.14.3 SDIV and UDIV
Signed Divide and Unsigned Divide.
10.14.3.1 Syntax
SDIV{cond} {Rd,} Rn, Rm
UDIV{cond} {Rd,} Rn, Rm
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register. If Rd is omitted, the destination register is Rn.
Rn is the register holding the value to be divided.
Rm is a register holding the divisor.
10.14.3.2 Operation
SDIV performs a signed integer division of the value in Rn by the value in Rm.
UDIV performs an unsigned integer division of the value in Rn by the value in Rm.
For both instructions, if the value in Rn is not divisible by the value in Rm, the result is rounded towards zero.
10.14.3.3 Restrictions
Do not use SP and do not use PC
.
10.14.3.4 Condition flags
These instructions do not change the flags.
10.14.3.5 Examples
SDIV R0, R2, R4 ; Signed divide, R0 = R2/R4
UDIV R8, R8, R1 ; Unsigned divide, R8 = R8/R1
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10.15 Saturating instructions
This section describes the saturating instructions, SSAT and USAT.
10.15.1 SSAT and USAT
Signed Saturate and Unsigned Saturate to any bit position, with optional shift before saturating.
10.15.1.1 Syntax
op{cond} Rd, #n, Rm {, shift #s}
where:
op is one of:
SSAT Saturates a signed value to a signed range.
USAT Saturates a signed value to an unsigned range.
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register.
n specifies the bit position to saturate to:
n ranges from 1 to 32 for SSAT
n ranges from 0 to 31 for USAT.
Rm is the register containing the value to saturate.
shift #s is an optional shift applied to Rm before saturating. It must be one of the following:
ASR #s where s is in the range 1 to 31
LSL #s where s is in the range 0 to 31.
10.15.1.2 Operation
These instructions saturate to a signed or unsigned n-bit value.
The SSAT instruction applies the specified shift, then saturates to the signed range −2n–1 ≤x≤2n–1−1.
The USAT instruction applies the specified shift, then saturates to the unsigned range 0 ≤x≤2n−1.
For signed n-bit saturation using SSAT, this means that:
if the value to be saturated is less than −2n−1, the result returned is −2n-1
if the value to be saturated is greater than 2n−1−1, the result returned is 2n-1−1
otherwise, the result returned is the same as the value to be saturated.
For unsigned n-bit saturation using USAT, this means that:
if the value to be saturated is less than 0, the result returned is 0
if the value to be saturated is greater than 2n−1, the result returned is 2n−1
otherwise, the result returned is the same as the value to be saturated.
If the returned result is different from the value to be saturated, it is called saturation. If saturation occurs, the
instruction sets the Q flag to 1 in the APSR. Otherwise, it leaves the Q flag unchanged. To clear the Q flag to 0,
you must use the MSR instruction, see “MSR” on page 147.
To read the state of the Q flag, use the MRS instruction, see “MRS” on page 146.
10.15.1.3 Restrictions
Do not use SP and do not use PC
.
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10.15.1.4 Condition flags
These instructions do not affect the condition code flags.
If saturation occurs, these instructions set the Q flag to 1.
10.15.1.5 Examples
SSAT R7, #16, R7, LSL #4 ; Logical shift left value in R7 by 4, then
; saturate it as a signed 16-bit value and
; write it back to R7
USATNE R0, #7, R5 ; Conditionally saturate value in R5 as an
; unsigned 7 bit value and write it to R0
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10.16 Bitfield instructions
Table 10-22 shows the instructions that operate on adjacent sets of bits in registers or bitfields:
Table 10-22. Packing and unpacking instructions
Mnemonic Brief description See
BFC Bit Field Clear “BFC and BFI” on page 130
BFI Bit Field Insert “BFC and BFI” on page 130
SBFX Signed Bit Field Extract “SBFX and UBFX” on page 131
SXTB Sign extend a byte “SXT and UXT” on page 132
SXTH Sign extend a halfword “SXT and UXT” on page 132
UBFX Unsigned Bit Field Extract “SBFX and UBFX” on page 131
UXTB Zero extend a byte “SXT and UXT” on page 132
UXTH Zero extend a halfword “SXT and UXT” on page 132
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10.16.1 BFC and BFI
Bit Field Clear and Bit Field Insert.
10.16.1.1 Syntax
BFC{cond} Rd, #lsb, #width
BFI{cond} Rd, Rn, #lsb, #width
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register.
Rn is the source register.
lsb is the position of the least significant bit of the bitfield.
lsb must be in the range 0 to 31.
width is the width of the bitfield and must be in the range 1 to 32−lsb.
10.16.1.2 Operation
BFC clears a bitfield in a register. It clears width bits in Rd, starting at the low bit position lsb. Other bits in Rd are
unchanged.
BFI copies a bitfield into one register from another register. It replaces width bits in Rd starting at the low bit
position lsb, with width bits from Rn starting at bit[0]. Other bits in Rd are unchanged.
10.16.1.3 Restrictions
Do not use SP and do not use PC.
10.16.1.4 Condition flags
These instructions do not affect the flags.
10.16.1.5 Examples
BFC R4, #8, #12 ; Clear bit 8 to bit 19 (12 bits) of R4 to 0
BFI R9, R2, #8, #12 ; Replace bit 8 to bit 19 (12 bits) of R9 with
; bit 0 to bit 11 from R2
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10.16.2 SBFX and UBFX
Signed Bit Field Extract and Unsigned Bit Field Extract.
10.16.2.1 Syntax
SBFX{cond} Rd, Rn, #lsb, #width
UBFX{cond} Rd, Rn, #lsb, #width
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register.
Rn is the source register.
lsb is the position of the least significant bit of the bitfield.
lsb must be in the range 0 to 31.
width is the width of the bitfield and must be in the range 1 to 32−lsb.
10.16.2.2 Operation
SBFX extracts a bitfield from one register, sign extends it to 32 bits, and writes the result to the destination register.
UBFX extracts a bitfield from one register, zero extends it to 32 bits, and writes the result to the destination
register.
10.16.2.3 Restrictions
Do not use SP and do not use PC
.
10.16.2.4 Condition flags
These instructions do not affect the flags.
10.16.2.5 Examples
SBFX R0, R1, #20, #4 ; Extract bit 20 to bit 23 (4 bits) from R1 and sign
; extend to 32 bits and then write the result to R0.
UBFX R8, R11, #9, #10 ; Extract bit 9 to bit 18 (10 bits) from R11 and zero
; extend to 32 bits and then write the result to R8
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10.16.3 SXT and UXT
Sign extend and Zero extend.
10.16.3.1 Syntax
SXTextend{cond} {Rd,} Rm {, ROR #n}
UXTextend{cond} {Rd}, Rm {, ROR #n}
where:
extend is one of:
B Extends an 8-bit value to a 32-bit value.
H Extends a 16-bit value to a 32-bit value.
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register.
Rm is the register holding the value to extend.
ROR #nis one of:
ROR #8 Value from Rm is rotated right 8 bits.
ROR #16 Value from Rm is rotated right 16 bits.
ROR #24 Value from Rm is rotated right 24 bits.
If ROR #n is omitted, no rotation is performed.
10.16.3.2 Operation
These instructions do the following:
Rotate the value from
Rm
right by 0, 8, 16 or 24 bits.
Extract bits from the resulting value:
SXTB extracts bits[7:0] and sign extends to 32 bits.
UXTB extracts bits[7:0] and zero extends to 32 bits.
SXTH extracts bits[15:0] and sign extends to 32 bits.
UXTH extracts bits[15:0] and zero extends to 32 bits.
10.16.3.3 Restrictions
Do not use SP and do not use PC.
10.16.3.4 Condition flags
These instructions do not affect the flags.
10.16.3.5 Examples
SXTH R4, R6, ROR #16 ; Rotate R6 right by 16 bits, then obtain the lower
; halfword of the result and then sign extend to
; 32 bits and write the result to R4.
UXTB R3, R10 ; Extract lowest byte of the value in R10 and zero
; extend it, and write the result to R3
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10.17 Branch and control instructions
Table 10-23 shows the branch and control instructions:
Table 10-23. Branch and control instructions
Mnemonic Brief description See
BBranch “B, BL, BX, and BLX” on page 134
BL Branch with Link “B, BL, BX, and BLX” on page 134
BLX Branch indirect with Link “B, BL, BX, and BLX” on page 134
BX Branch indirect “B, BL, BX, and BLX” on page 134
CBNZ Compare and Branch if Non Zero “CBZ and CBNZ” on page 136
CBZ Compare and Branch if Non Zero “CBZ and CBNZ” on page 136
IT If-Then “IT” on page 137
TBB Table Branch Byte “TBB and TBH” on page 139
TBH Table Branch Halfword “TBB and TBH” on page 139
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10.17.1 B, BL, BX, and BLX
Branch instructions.
10.17.1.1 Syntax
B{cond} label
BL{cond} label
BX{cond} Rm
BLX{cond} Rm
where:
B is branch (immediate).
BL is branch with link (immediate).
BX is branch indirect (register).
BLX is branch indirect with link (register).
cond is an optional condition code, see “Conditional execution” on page 91.
label is a PC-relative expression. See “PC-relative expressions” on page 90.
Rm is a register that indicates an address to branch to. Bit[0] of the value in Rm must be 1, but the
address to branch to is created by changing bit[0] to 0.
10.17.1.2 Operation
All these instructions cause a branch to label, or to the address indicated in Rm. In addition:
The BL and BLX instructions write the address of the next instruction to LR (the link register, R14).
The BX and BLX instructions cause a UsageFault exception if bit[0] of Rm is 0.
Bcond label is the only conditional instruction that can be either inside or outside an IT block. All other branch
instructions must be conditional inside an IT block, and must be unconditional outside the IT block, see “IT” on
page 137.
Table 10-24 shows the ranges for the various branch instructions.
You might have to use the .W suffix to get the maximum branch range. See “Instruction width selection” on page
92.
10.17.1.3 Restrictions
The restrictions are:
do not use PC in the BLX instruction
for BX and BLX, bit[0] of Rm must be 1 for correct execution but a branch occurs to the target address
created by changing bit[0] to 0
when any of these instructions is inside an IT block, it must be the last instruction of the IT block.
Table 10-24. Branch ranges
Instruction Branch range
B label −16 MB to +16 MB
B
cond
label
(outside IT block) −1 MB to +1 MB
B
cond
label
(inside IT block) −16 MB to +16 MB
BL{cond} label −16 MB to +16 MB
BX{cond} Rm Any value in register
BLX{cond} Rm Any value in register
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Bcond is the only conditional instruction that is not required to be inside an IT block. However, it has a longer
branch range when it is inside an IT block.
10.17.1.4 Condition flags
These instructions do not change the flags.
10.17.1.5 Examples
B loopA ; Branch to loopA
BLE ng ; Conditionally branch to label ng
B.W target ; Branch to target within 16MB range
BEQ target ; Conditionally branch to target
BEQ.W target ; Conditionally branch to target within 1MB
BL funC ; Branch with link (Call) to function funC, return address
; stored in LR
BX LR ; Return from function call
BXNE R0 ; Conditionally branch to address stored in R0
BLX R0 ; Branch with link and exchange (Call) to a address stored
; in R0
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10.17.2 CBZ and CBNZ
Compare and Branch on Zero, Compare and Branch on Non-Zero.
10.17.2.1 Syntax
CBZ Rn, label
CBNZ Rn, label
where:
Rn is the register holding the operand.
label is the branch destination.
10.17.2.2 Operation
Use the CBZ or CBNZ instructions to avoid changing the condition code flags and to reduce the number of
instructions.
CBZ Rn, label does not change condition flags but is otherwise equivalent to:
CMP Rn, #0
BEQ label
CBNZ Rn, label does not change condition flags but is otherwise equivalent to:
CMP Rn, #0
BNE label
10.17.2.3 Restrictions
The restrictions are:
Rn must be in the range of R0 to R7
the branch destination must be within 4 to 130 bytes after the instruction
these instructions must not be used inside an IT block.
10.17.2.4 Condition flags
These instructions do not change the flags.
10.17.2.5 Examples
CBZ R5, target ; Forward branch if R5 is zero
CBNZ R0, target ; Forward branch if R0 is not zero
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10.17.3 IT
If-Then condition instruction.
10.17.3.1 Syntax
IT{x{y{z}}} cond
where:
x specifies the condition switch for the second instruction in the IT block.
y specifies the condition switch for the third instruction in the IT block.
z specifies the condition switch for the fourth instruction in the IT block.
cond specifies the condition for the first instruction in the IT block.
The condition switch for the second, third and fourth instruction in the IT block can be either:
T Then. Applies the condition cond to the instruction.
E Else. Applies the inverse condition of cond to the instruction.
It is possible to use AL (the always condition) for cond in an IT instruction. If this is done, all of the instructions in
the IT block must be unconditional, and each of x, y, and z must be T or omitted but not E.
10.17.3.2 Operation
The IT instruction makes up to four following instructions conditional. The conditions can be all the same, or some
of them can be the logical inverse of the others. The conditional instructions following the IT instruction form the IT
block.
The instructions in the IT block, including any branches, must specify the condition in the {cond} part of their
syntax.
Your assembler might be able to generate the required IT instructions for conditional instructions automatically, so
that you do not need to write them yourself. See your assembler documentation for details.
A BKPT instruction in an IT block is always executed, even if its condition fails.
Exceptions can be taken between an IT instruction and the corresponding IT block, or within an IT block. Such an
exception results in entry to the appropriate exception handler, with suitable return information in LR and stacked
PSR.
Instructions designed for use for exception returns can be used as normal to return from the exception, and
execution of the IT block resumes correctly. This is the only way that a PC-modifying instruction is permitted to
branch to an instruction in an IT block.
10.17.3.3 Restrictions
The following instructions are not permitted in an IT block:
IT
CBZ and CBNZ
CPSID and CPSIE.
Other restrictions when using an IT block are:
a branch or any instruction that modifies the PC must either be outside an IT block or must be the last
instruction inside the IT block. These are:
̶ADD PC, PC, Rm
̶MOV PC, Rm
̶B, BL, BX, BLX
̶any LDM, LDR, or POP instruction that writes to the PC
̶TBB and TBH
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do not branch to any instruction inside an IT block, except when returning from an exception handler
all conditional instructions except Bcond must be inside an IT block. Bcond can be either outside or inside an
IT block but has a larger branch range if it is inside one
each instruction inside the IT block must specify a condition code suffix that is either the same or logical
inverse as for the other instructions in the block.
Your assembler might place extra restrictions on the use of IT blocks, such as prohibiting the use of assembler
directives within them.
10.17.3.4 Condition flags
This instruction does not change the flags.
10.17.3.5 Example
ITTE NE ; Next 3 instructions are conditional
ANDNE R0, R0, R1 ; ANDNE does not update condition flags
ADDSNE R2, R2, #1 ; ADDSNE updates condition flags
MOVEQ R2, R3 ; Conditional move
CMP R0, #9 ; Convert R0 hex value (0 to 15) into ASCII
; ('0'-'9', 'A'-'F')
ITE GT ; Next 2 instructions are conditional
ADDGT R1, R0, #55 ; Convert 0xA -> 'A'
ADDLE R1, R0, #48 ; Convert 0x0 -> '0'
IT GT ; IT block with only one conditional instruction
ADDGT R1, R1, #1 ; Increment R1 conditionally
ITTEE EQ ; Next 4 instructions are conditional
MOVEQ R0, R1 ; Conditional move
ADDEQ R2, R2, #10 ; Conditional add
ANDNE R3, R3, #1 ; Conditional AND
BNE.W dloop ; Branch instruction can only be used in the last
; instruction of an IT block
IT NE ; Next instruction is conditional
ADD R0, R0, R1 ; Syntax error: no condition code used in IT block
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10.17.4 TBB and TBH
Table Branch Byte and Table Branch Halfword.
10.17.4.1 Syntax
TBB [Rn, Rm]
TBH [Rn, Rm, LSL #1]
where:
Rn is the register containing the address of the table of branch lengths. If Rn is PC, then the address of
the table is the address of the byte immediately following the TBB or TBH instruction.
Rm is the index register. This contains an index into the table. For halfword tables, LSL #1 doubles the
value in Rm to form the right offset into the table.
10.17.4.2 Operation
These instructions cause a PC-relative forward branch using a table of single byte offsets for TBB, or halfword
offsets for TBH. Rn provides a pointer to the table, and Rm supplies an index into the table. For TBB the branch
offset is twice the unsigned value of the byte returned from the table. and for TBH the branch offset is twice the
unsigned value of the halfword returned from the table. The branch occurs to the address at that offset from the
address of the byte immediately after the TBB or TBH instruction.
10.17.4.3 Restrictions
The restrictions are:
Rn must not be SP
Rm must not be SP and must not be PC
when any of these instructions is used inside an IT block, it must be the last instruction of the IT block.
10.17.4.4 Condition flags
These instructions do not change the flags.
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10.17.4.5 Examples
ADR.W R0, BranchTable_Byte
TBB [R0, R1] ; R1 is the index, R0 is the base address of the
; branch table
Case1
; an instruction sequence follows
Case2
; an instruction sequence follows
Case3
; an instruction sequence follows
BranchTable_Byte
DCB 0 ; Case1 offset calculation
DCB ((Case2-Case1)/2) ; Case2 offset calculation
DCB ((Case3-Case1)/2) ; Case3 offset calculation
TBH [PC, R1, LSL #1] ; R1 is the index, PC is used as base of the
; branch table
BranchTable_H
DCI ((CaseA - BranchTable_H)/2) ; CaseA offset calculation
DCI ((CaseB - BranchTable_H)/2) ; CaseB offset calculation
DCI ((CaseC - BranchTable_H)/2) ; CaseC offset calculation
CaseA
; an instruction sequence follows
CaseB
; an instruction sequence follows
CaseC
; an instruction sequence follows
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10.18 Miscellaneous instructions
Table 10-25 shows the remaining Cortex-M3 instructions:
Table 10-25. Miscellaneous instructions
Mnemonic Brief description See
BKPT Breakpoint “BKPT” on page 142
CPSID Change Processor State, Disable
Interrupts “CPS” on page 143
CPSIE Change Processor State, Enable
Interrupts “CPS” on page 143
DMB Data Memory Barrier “DMB” on page 144
DSB Data Synchronization Barrier “DSB” on page 144
ISB Instruction Synchronization Barrier “ISB” on page 145
MRS Move from special register to register “MRS” on page 146
MSR Move from register to special register “MSR” on page 147
NOP No Operation “NOP” on page 148
SEV Send Event “SEV” on page 148
SVC Supervisor Call “SVC” on page 149
WFE Wait For Event “WFE” on page 150
WFI Wait For Interrupt “WFI” on page 151
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10.18.1 BKPT
Breakpoint.
10.18.1.1 Syntax
BKPT #imm
where:
imm is an expression evaluating to an integer in the range 0-255 (8-bit value).
10.18.1.2 Operation
The BKPT instruction causes the processor to enter Debug state. Debug tools can use this to investigate system
state when the instruction at a particular address is reached.
imm is ignored by the processor. If required, a debugger can use it to store additional information about the
breakpoint.
The BKPT instruction can be placed inside an IT block, but it executes unconditionally, unaffected by the condition
specified by the IT instruction.
10.18.1.3 Condition flags
This instruction does not change the flags.
10.18.1.4 Examples
BKPT 0xAB ; Breakpoint with immediate value set to 0xAB (debugger can
; extract the immediate value by locating it using the PC)
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10.18.2 CPS
Change Processor State.
10.18.2.1 Syntax
CPSeffect iflags
where:
effect is one of:
IE Clears the special purpose register.
ID Sets the special purpose register.
iflags is a sequence of one or more flags:
i Set or clear PRIMASK.
f Set or clear FAULTMASK.
10.18.2.2 Operation
CPS changes the PRIMASK and FAULTMASK special register values. See “Exception mask registers” on page 56
for more information about these registers.
10.18.2.3 Restrictions
The restrictions are:
use CPS only from privileged software, it has no effect if used in unprivileged software
CPS cannot be conditional and so must not be used inside an IT block.
10.18.2.4 Condition flags
This instruction does not change the condition flags.
10.18.2.5 Examples
CPSID i ; Disable interrupts and configurable fault handlers (set PRIMASK)
CPSID f ; Disable interrupts and all fault handlers (set FAULTMASK)
CPSIE i ; Enable interrupts and configurable fault handlers (clear PRIMASK)
CPSIE f ; Enable interrupts and fault handlers (clear FAULTMASK)
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10.18.3 DMB
Data Memory Barrier.
10.18.3.1 Syntax
DMB{cond}
where:
cond is an optional condition code, see “Conditional execution” on page 91.
10.18.3.2 Operation
DMB acts as a data memory barrier. It ensures that all explicit memory accesses that appear, in program order,
before the DMB instruction are completed before any explicit memory accesses that appear, in program order,
after the DMB instruction. DMB does not affect the ordering or execution of instructions that do not access
memory.
10.18.3.3 Condition flags
This instruction does not change the flags.
10.18.3.4 Examples
DMB ; Data Memory Barrier
10.18.4 DSB
Data Synchronization Barrier.
10.18.4.1 Syntax
DSB{cond}
where:
cond is an optional condition code, see “Conditional execution” on page 91.
10.18.4.2 Operation
DSB acts as a special data synchronization memory barrier. Instructions that come after the DSB, in program
order, do not execute until the DSB instruction completes. The DSB instruction completes when all explicit memory
accesses before it complete.
10.18.4.3 Condition flags
This instruction does not change the flags.
10.18.4.4 Examples
DSB ; Data Synchronisation Barrier
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10.18.5 ISB
Instruction Synchronization Barrier.
10.18.5.1 Syntax
ISB{cond}
where:
cond is an optional condition code, see “Conditional execution” on page 91.
10.18.5.2 Operation
ISB acts as an instruction synchronization barrier. It flushes the pipeline of the processor, so that all instructions
following the ISB are fetched from memory again, after the ISB instruction has been completed.
10.18.5.3 Condition flags
This instruction does not change the flags.
10.18.5.4 Examples
ISB ; Instruction Synchronisation Barrier
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10.18.6 MRS
Move the contents of a special register to a general-purpose register.
10.18.6.1 Syntax
MRS{cond} Rd, spec_reg
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rd is the destination register.
spec_reg can be any of: APSR, IPSR, EPSR, IEPSR, IAPSR, EAPSR, PSR, MSP, PSP, PRIMASK,
BASEPRI, BASEPRI_MAX, FAULTMASK, or CONTROL.
10.18.6.2 Operation
Use MRS in combination with MSR as part of a read-modify-write sequence for updating a PSR, for example to
clear the Q flag.
In process swap code, the programmers model state of the process being swapped out must be saved, including
relevant PSR contents. Similarly, the state of the process being swapped in must also be restored. These
operations use MRS in the state-saving instruction sequence and MSR in the state-restoring instruction sequence.
BASEPRI_MAX is an alias of BASEPRI when used with the MRS instruction.
See “MSR” on page 147.
10.18.6.3 Restrictions
Rd must not be SP and must not be PC.
10.18.6.4 Condition flags
This instruction does not change the flags.
10.18.6.5 Examples
MRS R0, PRIMASK ; Read PRIMASK value and write it to R0
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10.18.7 MSR
Move the contents of a general-purpose register into the specified special register.
10.18.7.1 Syntax
MSR{cond} spec_reg, Rn
where:
cond is an optional condition code, see “Conditional execution” on page 91.
Rn is the source register.
spec_reg can be any of: APSR, IPSR, EPSR, IEPSR, IAPSR, EAPSR, PSR, MSP, PSP, PRIMASK,
BASEPRI, BASEPRI_MAX, FAULTMASK, or CONTROL.
10.18.7.2 Operation
The register access operation in MSR depends on the privilege level. Unprivileged software can only access the
APSR, see “Application Program Status Register” on page 54. Privileged software can access all special registers.
In unprivileged software writes to unallocated or execution state bits in the PSR are ignored.
When you write to BASEPRI_MAX, the instruction writes to BASEPRI only if either:
Rn is non-zero and the current BASEPRI value is 0
Rn is non-zero and less than the current BASEPRI value.
See “MRS” on page 146.
10.18.7.3 Restrictions
Rn must not be SP and must not be PC.
10.18.7.4 Condition flags
This instruction updates the flags explicitly based on the value in Rn.
10.18.7.5 Examples
MSR CONTROL, R1 ; Read R1 value and write it to the CONTROL register
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10.18.8 NOP
No Operation.
10.18.8.1 Syntax
NOP{cond}
where:
cond is an optional condition code, see “Conditional execution” on page 91.
10.18.8.2 Operation
NOP does nothing. NOP is not necessarily a time-consuming NOP. The processor might remove it from the
pipeline before it reaches the execution stage.
Use NOP for padding, for example to place the following instruction on a 64-bit boundary.
10.18.8.3 Condition flags
This instruction does not change the flags.
10.18.8.4 Examples
NOP ; No operation
10.18.9 SEV
Send Event.
10.18.9.1 Syntax
SEV{cond}
where:
cond is an optional condition code, see “Conditional execution” on page 91.
10.18.9.2 Operation
SEV is a hint instruction that causes an event to be signaled to all processors within a multiprocessor system. It
also sets the local event register to 1, see “Power management” on page 80.
10.18.9.3 Condition flags
This instruction does not change the flags.
10.18.9.4 Examples
SEV ; Send Event
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10.18.10 SVC
Supervisor Call.
10.18.10.1 Syntax
SVC{cond} #imm
where:
cond is an optional condition code, see “Conditional execution” on page 91.
imm is an expression evaluating to an integer in the range 0-255 (8-bit value).
10.18.10.2 Operation
The SVC instruction causes the SVC exception.
imm is ignored by the processor. If required, it can be retrieved by the exception handler to determine what service
is being requested.
10.18.10.3 Condition flags
This instruction does not change the flags.
10.18.10.4 Examples
SVC 0x32 ; Supervisor Call (SVC handler can extract the immediate value
; by locating it via the stacked PC)
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10.18.11 WFE
Wait For Event.
10.18.11.1 Syntax
WFE{cond}
where:
cond is an optional condition code, see “Conditional execution” on page 91.
10.18.11.2 Operation
WFE is a hint instruction.
If the event register is 0, WFE suspends execution until one of the following events occurs:
an exception, unless masked by the exception mask registers or the current priority level
an exception enters the Pending state, if SEVONPEND in the System Control Register is set
a Debug Entry request, if Debug is enabled
an event signaled by a peripheral or another processor in a multiprocessor system using the SEV
instruction.
If the event register is 1, WFE clears it to 0 and returns immediately.
For more information see “Power management” on page 80.
10.18.11.3 Condition flags
This instruction does not change the flags.
10.18.11.4 Examples
WFE ; Wait for event
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10.18.12 WFI
Wait for Interrupt.
10.18.12.1 Syntax
WFI{cond}
where:
cond is an optional condition code, see “Conditional execution” on page 91.
10.18.12.2 Operation
WFI is a hint instruction that suspends execution until one of the following events occurs:
an exception
a Debug Entry request, regardless of whether Debug is enabled.
10.18.12.3 Condition flags
This instruction does not change the flags.
10.18.12.4 Examples
WFI ; Wait for interrupt
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10.19 About the Cortex-M3 peripherals
The address map of the Private peripheral bus (PPB) is:
In register descriptions:
the register type is described as follows:
RW Read and write.
RO Read-only.
WO Write-only.
the required privilege gives the privilege level required to access the register, as follows:
Privileged Only privileged software can access the register.
Unprivileged Both unprivileged and privileged software can access the register.
10.20 Nested Vectored Interrupt Controller
This section describes the Nested Vectored Interrupt Controller (NVIC) and the registers it uses. The NVIC
supports:
1 to 30 interrupts.
A programmable priority level of 0-15 for each interrupt. A higher level corresponds to a lower priority, so
level 0 is the highest interrupt priority.
Level detection of interrupt signals.
Dynamic reprioritization of interrupts.
Grouping of priority values into group priority and subpriority fields.
Interrupt tail-chaining.
Table 10-26. Core peripheral register regions
Address Core peripheral Description
0xE000E008
-
0xE000E00F
System control block Table 10-30 on page 165
0xE000E010
-
0xE000E01F
System timer Table 10-33 on page 192
0xE000E100
-
0xE000E4EF
Nested Vectored Interrupt
Controller Table 10-27 on page 153
0xE000ED00
-
0xE000ED3F
System control block Table 10-30 on page 165
0xE000ED90
-
0xE000EDB8
Memory protection unit Table 10-35 on page 198
0xE000EF00
-
0xE000EF03
Nested Vectored Interrupt
Controller Table 10-27 on page 153
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The processor automatically stacks its state on exception entry and unstacks this state on exception exit, with no
instruction overhead. This provides low latency exception handling. The hardware implementation of the NVIC
registers is:
10.20.1 The CMSIS mapping of the Cortex-M3 NVIC registers
To improve software efficiency, the CMSIS simplifies the NVIC register presentation. In the CMSIS:
the Set-enable, Clear-enable, Set-pending, Clear-pending and Active Bit registers map to arrays of 32-bit
integers, so that:
̶the array
ISER[0]
to
ISER[1]
corresponds to the registers ISER0-ISER1
̶the array
ICER[0] to ICER[1]
corresponds to the registers ICER0-ICER1
̶the array
ISPR[0] to ISPR[1]
corresponds to the registers ISPR0-
ISPR1
̶the array
ICPR[0] to ICPR[1]
corresponds to the registers ICPR0-
ICPR1
̶the array
IABR[0] to IABR[1]
corresponds to the registers IABR0-
IABR1
the 4-bit fields of the Interrupt Priority Registers map to an array of 4-bit integers, so that the array IP[0] to
IP[29] corresponds to the registers IPR0-IPR7, and the array entry IP[n] holds the interrupt priority for
interrupt n.
The CMSIS provides thread-safe code that gives atomic access to the Interrupt Priority Registers. For more
information see the description of the NVIC_SetPriority function in “NVIC programming hints” on page 164. Table
10-28 shows how the interrupts, or IRQ numbers, map onto the interrupt registers and corresponding CMSIS
variables that have one bit per interrupt.
Table 10-27. NVIC register summary
Address Name Type Required privilege Reset value Description
0xE000E100
-
0xE000E104
ISER0-
ISER1
RW Privileged 0x00000000 “Interrupt Set-enable Registers” on page 155
0xE000E180-
0xE000E184 ICER0-
ICER1
RW Privileged 0x00000000 “Interrupt Clear-enable Registers” on page 156
0xE000E200-
0xE000E204
ISPR0-
ISPR1
RW Privileged 0x00000000 “Interrupt Set-pending Registers” on page 157
0xE000E280-
0xE000E284 ICPR0-
ICPR1
RW Privileged 0x00000000 “Interrupt Clear-pending Registers” on page 158
0xE000E300-
0xE000E304 IABR0-
IABR1
RO Privileged 0x00000000 “Interrupt Active Bit Registers” on page 159
0xE000E400-
0xE000E41C
IPR0-
IPR7 RW Privileged 0x00000000 “Interrupt Priority Registers” on page 160
0xE000EF00 STIR WO Configurable (1) 0x00000000 “Software Trigger Interrupt Register” on page 162
1. See the register description for more information.
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Table 10-28. Mapping of interrupts to the interrupt variables
Interrupts
CMSIS array elements (1)
1. Each array element corresponds to a single NVIC register, for example the element
ICER[0]
corresponds to the ICER0 register.
Set-enable Clear-enable Set-pending Clear-pending Active Bit
0-29 ISER[0] ICER[0] ISPR[0] ICPR[0] IABR[0]
30-63 ISER[1] ICER[1] ISPR[1] ICPR[1] IABR[1]
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10.20.2 Interrupt Set-enable Registers
The ISER0-ISER1 register enables interrupts, and show which interrupts are enabled. See:
the register summary in Table 10-27 on page 153 for the register attributes
Table 10-28 on page 154 for which interrupts are controlled by each register.
The bit assignments are:
• SETENA
Interrupt set-enable bits.
Write:
0: no effect
1: enable interrupt.
Read:
0: interrupt disabled
1: interrupt enabled.
If a pending interrupt is enabled, the NVIC activates the interrupt based on its priority. If an interrupt is not enabled, assert-
ing its interrupt signal changes the interrupt state to pending, but the NVIC never activates the interrupt, regardless of its
priority.
3130292827 26 25 24
SETENA bits
2322 21 20 19 1817 16
SETENA bits
15 14 1312 11 10 9 8
SETENA bits
76543210
SETENA bits
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10.20.3 Interrupt Clear-enable Registers
The ICER0-ICER1 register disables interrupts, and shows which interrupts are enabled. See:
the register summary in Table 10-27 on page 153 for the register attributes
Table 10-28 on page 154 for which interrupts are controlled by each register
The bit assignments are:
•CLRENA
Interrupt clear-enable bits.
Write:
0: no effect
1: disable interrupt.
Read:
0: interrupt disabled
1: interrupt enabled.
3130292827 26 25 24
CLRENA
2322 21 20 19 1817 16
CLRENA
15 14 1312 11 10 9 8
CLRENA
76543210
CLRENA
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10.20.4 Interrupt Set-pending Registers
The ISPR0-ISPR1 register forces interrupts into the pending state, and shows which interrupts are pending. See:
the register summary in Table 10-27 on page 153 for the register attributes
Table 10-28 on page 154 for which interrupts are controlled by each register.
The bit assignments are:
• SETPEND
Interrupt set-pending bits.
Write:
0: no effect.
1: changes interrupt state to pending.
Read:
0: interrupt is not pending.
1: interrupt is pending.
Writing 1 to the ISPR bit corresponding to:
•an interrupt that is pending has no effect
•a disabled interrupt sets the state of that interrupt to pending
3130292827 26 25 24
SETPEND
2322 21 20 19 1817 16
SETPEND
15 14 1312 11 10 9 8
SETPEND
76543210
SETPEND
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10.20.5 Interrupt Clear-pending Registers
The ICPR0-ICPR1 register removes the pending state from interrupts, and show which interrupts are pending.
See:
the register summary in Table 10-27 on page 153 for the register attributes
Table 10-28 on page 154 for which interrupts are controlled by each register.
The bit assignments are:
• CLRPEND
Interrupt clear-pending bits.
Write:
0: no effect.
1: removes pending state an interrupt.
Read:
0: interrupt is not pending.
1: interrupt is pending.
Writing 1 to an ICPR bit does not affect the active state of the corresponding interrupt.
3130292827 26 25 24
CLRPEND
2322 21 20 19 1817 16
CLRPEND
15 14 1312 11 10 9 8
CLRPEND
76543210
CLRPEND
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10.20.6 Interrupt Active Bit Registers
The IABR0-IABR1 register indicates which interrupts are active. See:
the register summary in Table 10-27 on page 153 for the register attributes
Table 10-28 on page 154 for which interrupts are controlled by each register.
The bit assignments are:
•ACTIVE
Interrupt active flags:
0: interrupt not active
1: interrupt active.
A bit reads as one if the status of the corresponding interrupt is active or active and pending.
3130292827 26 25 24
ACTIVE
2322 21 20 19 1817 16
ACTIVE
15 14 1312 11 10 9 8
ACTIVE
76543210
ACTIVE
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10.20.7 Interrupt Priority Registers
The IPR0-IPR7 registers provide a 4-bit priority field for each interrupt (See the “Peripheral Identifiers” section of
the datasheet for more details). These registers are byte-accessible. See the register summary in Table 10-27 on
page 153 for their attributes. Each register holds four priority fields, that map up to four elements in the CMSIS
interrupt priority array
IP[0]
to
IP[29]
, as shown:
10.20.7.1 IPRm
10.20.7.2 IPR4
10.20.7.3 IPR3
10.20.7.4 IPR2
3130292827 26 25 24
IP[4m+3]
2322 21 20 19 1817 16
IP[4m+2]
15 14 1312 11 10 9 8
IP[4m+1]
76543210
IP[4m]
3130292827 26 25 24
IP[19]
2322 21 20 19 1817 16
IP[18]
15 14 1312 11 10 9 8
IP[17]
76543210
IP[16]
3130292827 26 25 24
IP[15]
2322 21 20 19 1817 16
IP[14]
15 14 1312 11 10 9 8
IP[13]
76543210
IP[12]
3130292827 26 25 24
IP[11]
2322 21 20 19 1817 16
IP[10]
15 14 1312 11 10 9 8
IP[9]
76543210
IP[8]
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10.20.7.5 IPR1
10.20.7.6 IPR0
• Priority, byte offset 3
• Priority, byte offset 2
• Priority, byte offset 1
• Priority, byte offset 0
Each priority field holds a priority value, 0-15. The lower the value, the greater the priority of the corresponding interrupt.
The processor implements only bits[7:4] of each field, bits[3:0] read as zero and ignore writes.
See “The CMSIS mapping of the Cortex-M3 NVIC registers” on page 153 for more information about the IP[0] to IP[29]
interrupt priority array, that provides the software view of the interrupt priorities.
Find the IPR number and byte offset for interrupt N as follows:
• the corresponding IPR number, M, is given by M = N DIV 4
•the byte offset of the required Priority field in this register is N MOD 4, where:
–byte offset 0 refers to register bits[7:0]
–byte offset 1 refers to register bits[15:8]
–byte offset 2 refers to register bits[23:16]
–byte offset 3 refers to register bits[31:24].
3130292827 26 25 24
IP[7]
2322 21 20 19 1817 16
IP[6]
15 14 1312 11 10 9 8
IP[5]
76543210
IP[4]
3130292827 26 25 24
IP[3]
2322 21 20 19 1817 16
IP[2]
15 14 1312 11 10 9 8
IP[1]
76543210
IP[0]
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10.20.8 Software Trigger Interrupt Register
Write to the STIR to generate a Software Generated Interrupt (SGI). See the register summary in Table 10-27 on
page 153 for the STIR attributes.
When the USERSETMPEND bit in the SCR is set to 1, unprivileged software can access the STIR, see “System
Control Register” on page 174.
Only privileged software can enable unprivileged access to the STIR.
The bit assignments are:
•INTID
Interrupt ID of the required SGI, in the range 0-239. For example, a value of b000000011 specifies interrupt IRQ3.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved INTID
76543210
INTID
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10.20.9 Level-sensitive interrupts
The processor supports level-sensitive interrupts.
A level-sensitive interrupt is held asserted until the peripheral deasserts the interrupt signal. Typically this happens
because the ISR accesses the peripheral, causing it to clear the interrupt request.
When the processor enters the ISR, it automatically removes the pending state from the interrupt, see “Hardware
and software control of interrupts” . For a level-sensitive interrupt, if the signal is not deasserted before the
processor returns from the ISR, the interrupt becomes pending again, and the processor must execute its ISR
again. This means that the peripheral can hold the interrupt signal asserted until it no longer needs servicing.
10.20.9.1 Hardware and software control of interrupts
The Cortex-M3 latches all interrupts. A peripheral interrupt becomes pending for one of the following reasons:
the NVIC detects that the interrupt signal is HIGH and the interrupt is not active
the NVIC detects a rising edge on the interrupt signal
software writes to the corresponding interrupt set-pending register bit, see “Interrupt Set-pending Registers”
on page 157, or to the STIR to make an SGI pending, see “Software Trigger Interrupt Register” on page 162.
A pending interrupt remains pending until one of the following:
The processor enters the ISR for the interrupt. This changes the state of the interrupt from pending to active. Then:
̶For a level-sensitive interrupt, when the processor returns from the ISR, the NVIC samples the
interrupt signal. If the signal is asserted, the state of the interrupt changes to pending, which might
cause the processor to immediately re-enter the ISR. Otherwise, the state of the interrupt changes to
inactive.
̶If the interrupt signal is not pulsed while the processor is in the ISR, when the processor returns from
the ISR the state of the interrupt changes to inactive.
Software writes to the corresponding interrupt clear-pending register bit.
For a level-sensitive interrupt, if the interrupt signal is still asserted, the state of the interrupt does not change.
Otherwise, the state of the interrupt changes to inactive.
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10.20.10 NVIC design hints and tips
Ensure software uses correctly aligned register accesses. The processor does not support unaligned accesses to
NVIC registers. See the individual register descriptions for the supported access sizes.
A interrupt can enter pending state even it is disabled.
Before programming VTOR to relocate the vector table, ensure the vector table entries of the new vector table are
setup for fault handlers and all enabled exception like interrupts. For more information see “Vector Table Offset
Register” on page 171.
10.20.10.1 NVIC programming hints
Software uses the CPSIE I and CPSID I instructions to enable and disable interrupts. The CMSIS provides the
following intrinsic functions for these instructions:
void __disable_irq(void) // Disable Interrupts
void __enable_irq(void) // Enable Interrupts
In addition, the CMSIS provides a number of functions for NVIC control, including:
For more information about these functions see the CMSIS documentation.
Table 10-29. CMSIS functions for NVIC control
CMSIS interrupt control function Description
void NVIC_SetPriorityGrouping(uint32_t
priority_grouping) Set the priority grouping
void NVIC_EnableIRQ(IRQn_t IRQn) Enable IRQn
void NVIC_DisableIRQ(IRQn_t IRQn) Disable IRQn
uint32_t NVIC_GetPendingIRQ (IRQn_t IRQn) Return true if IRQn is pending
void NVIC_SetPendingIRQ (IRQn_t IRQn) Set IRQn pending
void NVIC_ClearPendingIRQ (IRQn_t IRQn) Clear IRQn pending status
uint32_t NVIC_GetActive (IRQn_t IRQn) Return the IRQ number of the active
interrupt
void NVIC_SetPriority (IRQn_t IRQn, uint32_t priority) Set priority for IRQn
uint32_t NVIC_GetPriority (IRQn_t IRQn) Read priority of IRQn
void NVIC_SystemReset (void) Reset the system
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10.21 System control block
The System control block (SCB) provides system implementation information, and system control. This includes
configuration, control, and reporting of the system exceptions. The system control block registers are:
Notes: 1. See the register description for more information.
2. A subregister of the CFSR.
10.21.1 The CMSIS mapping of the Cortex-M3 SCB registers
To improve software efficiency, the CMSIS simplifies the SCB register presentation. In the CMSIS, the byte array
SHP[0] to SHP[12] corresponds to the registers SHPR1-SHPR3.
Table 10-30. Summary of the system control block registers
Address Name Type Required
privilege Reset
value Description
0xE000E008 ACTLR RW Privileged 0x00000000 “Auxiliary Control Register” on page 166
0xE000ED00 CPUID RO Privileged 0x412FC230 “CPUID Base Register” on page 167
0xE000ED04 ICSR RW(1) Privileged 0x00000000 “Interrupt Control and State Register” on page 168
0xE000ED08 VTOR RW Privileged 0x00000000 “Vector Table Offset Register” on page 171
0xE000ED0C AIRCR RW(1) Privileged 0xFA050000 “Application Interrupt and Reset Control Register” on page
172
0xE000ED10 SCR RW Privileged 0x00000000 “System Control Register” on page 174
0xE000ED14 CCR RW Privileged 0x00000200 “Configuration and Control Register” on page 175
0xE000ED18 SHPR1 RW Privileged 0x00000000 “System Handler Priority Register 1” on page 178
0xE000ED1C SHPR2 RW Privileged 0x00000000 “System Handler Priority Register 2” on page 179
0xE000ED20 SHPR3 RW Privileged 0x00000000 “System Handler Priority Register 3” on page 179
0xE000ED24 SHCRS RW Privileged 0x00000000 “System Handler Control and State Register” on page 180
0xE000ED28 CFSR RW Privileged 0x00000000 “Configurable Fault Status Register” on page 182
0xE000ED28 MMSR(2) RW Privileged 0x00 “Memory Management Fault Address Register” on page
189
0xE000ED29 BFSR(2) RW Privileged 0x00 “Bus Fault Status Register” on page 184
0xE000ED2A UFSR(2) RW Privileged 0x0000 “Usage Fault Status Register” on page 186
0xE000ED2C HFSR RW Privileged 0x00000000 “Hard Fault Status Register” on page 188
0xE000ED34 MMAR RW Privileged Unknown “Memory Management Fault Address Register” on page
189
0xE000ED38 BFAR RW Privileged Unknown “Bus Fault Address Register” on page 190
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10.21.2 Auxiliary Control Register
The ACTLR provides disable bits for the following processor functions:
IT folding
write buffer use for accesses to the default memory map
interruption of multi-cycle instructions.
See the register summary in Table 10-30 on page 165 for the ACTLR attributes. The bit assignments are:
• DISFOLD
When set to 1, disables IT folding. see “About IT folding” on page 166 for more information.
•DISDEFWBUF
When set to 1, disables write buffer use during default memory map accesses. This causes all bus faults to be precise bus
faults but decreases performance because any store to memory must complete before the processor can execute the next
instruction.
This bit only affects write buffers implemented in the Cortex-M3 processor.
• DISMCYCINT
When set to 1, disables interruption of load multiple and store multiple instructions. This increases the interrupt latency of
the processor because any LDM or STM must complete before the processor can stack the current state and enter the
interrupt handler.
10.21.2.1 About IT folding
In some situations, the processor can start executing the first instruction in an IT block while it is still executing the
IT instruction. This behavior is called IT folding, and improves performance, However, IT folding can cause jitter in
looping. If a task must avoid jitter, set the DISFOLD bit to 1 before executing the task, to disable IT folding.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
Reserved DISFOLD DISDEFWBUF DISMCYCINT
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10.21.3 CPUID Base Register
The CPUID register contains the processor part number, version, and implementation information. See the register
summary in Table 10-30 on page 165 for its attributes. The bit assignments are:
• Implementer
Implementer code:
0x41 = ARM
•Variant
Variant number, the r value in the rnpn product revision identifier:
0x2 = r2p0
• Constant
Reads as 0xF
•PartNo
Part number of the processor:
0xC23 = Cortex-M3
• Revision
Revision number, the p value in the rnpn product revision identifier:
0x0 = r2p0
3130292827 26 25 24
Implementer
2322 21 20 19 1817 16
Variant Constant
15 14 1312 11 10 9 8
PartNo
76543210
PartNo Revision
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10.21.4 Interrupt Control and State Register
The ICSR:
provides:
̶set-pending and clear-pending bits for the PendSV and SysTick exceptions
indicates:
̶the exception number of the exception being processed
̶whether there are preempted active exceptions
̶the exception number of the highest priority pending exception
̶whether any interrupts are pending.
See the register summary in Table 10-30 on page 165, and the Type descriptions in Table 10-33 on page 192, for
the ICSR attributes. The bit assignments are:
• PENDSVSET
RW
PendSV set-pending bit.
Write:
0: no effect
1: changes PendSV exception state to pending.
Read:
0: PendSV exception is not pending
1: PendSV exception is pending.
Writing 1 to this bit is the only way to set the PendSV exception state to pending.
• PENDSVCLR
WO
PendSV clear-pending bit.
Write:
0: no effect
1: removes the pending state from the PendSV exception.
31 30 29 28 27 26 25 24
Reserved Reserved PENDSVSET PENDSVCLR PENDSTSET PENDSTCLR Reserved
23 22 21 20 19 18 17 16
Reserved for
Debug ISRPENDING VECTPENDING
15 14 13 12 11 10 9 8
VECTPENDING RETTOBASE Reserved VECTACTIVE
76543210
VECTACTIVE
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• PENDSTSET
RW
SysTick exception set-pending bit.
Write:
0: no effect
1: changes SysTick exception state to pending.
Read:
0: SysTick exception is not pending
1: SysTick exception is pending.
• PENDSTCLR
WO
SysTick exception clear-pending bit.
Write:
0: no effect
1: removes the pending state from the SysTick exception.
This bit is WO. On a register read its value is Unknown.
• Reserved for Debug use
RO
This bit is reserved for Debug use and reads-as-zero when the processor is not in Debug.
• ISRPENDING
RO
Interrupt pending flag, excluding Faults:
0: interrupt not pending
1: interrupt pending.
• VECTPENDING
RO
Indicates the exception number of the highest priority pending enabled exception:
0: no pending exceptions
Nonzero = the exception number of the highest priority pending enabled exception.
The value indicated by this field includes the effect of the BASEPRI and FAULTMASK registers, but not any effect of the
PRIMASK register.
• RETTOBASE
RO
Indicates whether there are preempted active exceptions:
0: there are preempted active exceptions to execute
1: there are no active exceptions, or the currently-executing exception is the only active exception.
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• VECTACTIVE
RO
Contains the active exception number:
0: Thread mode
Nonzero = The exception number (1) of the currently active exception.
Subtract 16 from this value to obtain the IRQ number required to index into the Interrupt Clear-Enable, Set-Enable, Clear-
Pending, Set-Pending, or Priority Registers, see “Interrupt Program Status Register” on page 54.
When you write to the ICSR, the effect is Unpredictable if you:
• write 1 to the PENDSVSET bit and write 1 to the PENDSVCLR bit
• write 1 to the PENDSTSET bit and write 1 to the PENDSTCLR bit.
Note: 1. This is the same value as IPSR bits [8:0] see “Interrupt Program Status Register” on page 54.
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10.21.5 Vector Table Offset Register
The VTOR indicates the offset of the vector table base address from memory address 0x00000000. See the
register summary in Table 10-30 on page 165 for its attributes.
The bit assignments are:
•TBLOFF
Vector table base offset field. It contains bits[29:7] of the offset of the table base from the bottom of the memory map.
Bit[29] determines whether the vector table is in the code or SRAM memory region:
0: code
1: SRAM.
Bit[29] is sometimes called the TBLBASE bit.
When setting TBLOFF, you must align the offset to the number of exception entries in the vector table. The minimum align-
ment is 32 words, enough for up to 16 interrupts. For more interrupts, adjust the alignment by rounding up to the next
power of two. For example, if you require 21 interrupts, the alignment must be on a 64-word boundary because the
required table size is 37 words, and the next power of two is 64.
Table alignment requirements mean that bits[6:0] of the table offset are always zero.
3130292827 26 25 24
Reserved TBLOFF
2322 21 20 19 1817 16
TBLOFF
15 14 1312 11 10 9 8
TBLOFF
76543210
TBLOFF Reserved
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10.21.6 Application Interrupt and Reset Control Register
The AIRCR provides priority grouping control for the exception model, endian status for data accesses, and reset
control of the system. See the register summary in Table 10-30 on page 165 and Table 10-33 on page 192 for its
attributes.
To write to this register, you must write
0x05FA
to the VECTKEY field, otherwise the processor ignores the write.
The bit assignments are:
• VECTKEYSTAT
Register Key:
Reads as 0xFA05
• VECTKEY
Register key:
On writes, write 0x5FA to VECTKEY, otherwise the write is ignored.
• ENDIANESS
RO
Data endianness bit:
0: Little-endian
ENDIANESS is set from the BIGEND configuration signal during reset.
•PRIGROUP
R/W
Interrupt priority grouping field. This field determines the split of group priority from subpriority, see “Binary point” on page
173.
• SYSRESETREQ
WO
System reset request:
0: no effect
1: asserts a proc_reset_signal.
This is intended to force a large system reset of all major components except for debug.
This bit reads as 0.
3130292827 26 25 24
On Read: VECTKEYSTAT, On Write: VECTKEY
2322 21 20 19 1817 16
On Read: VECTKEYSTAT, On Write: VECTKEY
15 14 1312 11 10 9 8
ENDIANESS Reserved PRIGROUP
76543210
Reserved
SYSRESETREQ
VECTCLR-
ACTIVE VECTRESET
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• VECTCLRACTIVE
WO
Reserved for Debug use. This bit reads as 0. When writing to the register you must write 0 to this bit, otherwise behavior is
Unpredictable.
• VECTRESET
WO
Reserved for Debug use. This bit reads as 0. When writing to the register you must write 0 to this bit, otherwise behavior is
Unpredictable.
10.21.6.1 Binary point
The PRIGROUP field indicates the position of the binary point that splits the PRI_n fields in the Interrupt Priority
Registers into separate group priority and subpriority fields. Table 10-31 shows how the PRIGROUP value controls
this split.
Determining preemption of an exception uses only the group priority field, see “Interrupt priority grouping” on page
75.
Table 10-31. Priority grouping
Interrupt priority level value, PRI_N[7:0] Number of
PRIGROUP Binary point (1)
1. PRI_n[7:0] field showing the binary point. x denotes a group priority field bit, and y denotes a subpriority field bit.
Group priority bits Subpriority bits Group priorities Subpriorities
b011 bxxxx.0000 [7:4] None 16 1
b100 bxxx.y0000 [7:5] [4] 8 2
b101 bxx.yy0000 [7:6] [5:4] 4 4
b110 bx.yyy0000 [7] [6:4] 2 8
b111 b.yyyy0000 None [7:4] 1 16
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10.21.7 System Control Register
The SCR controls features of entry to and exit from low power state. See the register summary in Table 10-30 on
page 165 for its attributes. The bit assignments are:
• SEVONPEND
Send Event on Pending bit:
0: only enabled interrupts or events can wakeup the processor, disabled interrupts are excluded
1: enabled events and all interrupts, including disabled interrupts, can wakeup the processor.
When an event or interrupt enters pending state, the event signal wakes up the processor from WFE. If the processor is not
waiting for an event, the event is registered and affects the next WFE.
The processor also wakes up on execution of an
SEV
instruction or an external event.
• SLEEPDEEP
Controls whether the processor uses sleep or deep sleep as its low power mode:
0: sleep
1: deep sleep.
• SLEEPONEXIT
Indicates sleep-on-exit when returning from Handler mode to Thread mode:
0: do not sleep when returning to Thread mode.
1: enter sleep, or deep sleep, on return from an ISR.
Setting this bit to 1 enables an interrupt driven application to avoid returning to an empty main application.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
Reserved SEVONPEND Reserved SLEEPDEEP SLEEONEXIT Reserved
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10.21.8 Configuration and Control Register
The CCR controls entry to Thread mode and enables:
the handlers for hard fault and faults escalated by FAULTMASK to ignore bus faults
trapping of divide by zero and unaligned accesses
access to the STIR by unprivileged software, see “Software Trigger Interrupt Register” on page 162.
See the register summary in Table 10-30 on page 165 for the CCR attributes.
The bit assignments are:
•STKALIGN
Indicates stack alignment on exception entry:
0: 4-byte aligned
1: 8-byte aligned.
On exception entry, the processor uses bit[9] of the stacked PSR to indicate the stack alignment. On return from the excep-
tion it uses this stacked bit to restore the correct stack alignment.
•BFHFNMIGN
Enables handlers with priority -1 or -2 to ignore data bus faults caused by load and store instructions. This applies to the
hard fault and FAULTMASK escalated handlers:
0: data bus faults caused by load and store instructions cause a lock-up
1: handlers running at priority -1 and -2 ignore data bus faults caused by load and store instructions.
Set this bit to 1 only when the handler and its data are in absolutely safe memory. The normal use of this bit is to probe sys-
tem devices and bridges to detect control path problems and fix them.
• DIV_0_TRP
Enables faulting or halting when the processor executes an SDIV or UDIV instruction with a divisor of 0:
0: do not trap divide by 0
1: trap divide by 0.
When this bit is set to 0,a divide by zero returns a quotient of 0.
• UNALIGN_TRP
Enables unaligned access traps:
0: do not trap unaligned halfword and word accesses
1: trap unaligned halfword and word accesses.
If this bit is set to 1, an unaligned access generates a usage fault.
Unaligned LDM, STM, LDRD, and STRD instructions always fault irrespective of whether UNALIGN_TRP is set to 1.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved STKALIGN BFHFNMIGN
76543210
Reserved DIV_0_TRP UNALIGN_T
RP Reserved USERSETM
PEND NONBASET
HRDENA
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• USERSETMPEND
Enables unprivileged software access to the STIR, see “Software Trigger Interrupt Register” on page 162:
0: disable
1: enable.
• NONEBASETHRDENA
Indicates how the processor enters Thread mode:
0: processor can enter Thread mode only when no exception is active.
1: processor can enter Thread mode from any level under the control of an EXC_RETURN value, see “Exception return”
on page 76.
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10.21.9 System Handler Priority Registers
The SHPR1-SHPR3 registers set the priority level, 0 to 15 of the exception handlers that have configurable priority.
SHPR1-SHPR3 are byte accessible. See the register summary in Table 10-30 on page 165 for their attributes.
The system fault handlers and the priority field and register for each handler are:
Each PRI_N field is 8 bits wide, but the processor implements only bits[7:4] of each field, and bits[3:0] read as zero
and ignore writes.
Table 10-32. System fault handler priority fields
Handler Field Register description
Memory management
fault PRI_4
“System Handler Priority Register 1” on page 178
Bus fault PRI_5
Usage fault PRI_6
SVCall PRI_11 “System Handler Priority Register 2” on page 179
PendSV PRI_14 “System Handler Priority Register 3” on page 179
SysTick PRI_15
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10.21.9.1 System Handler Priority Register 1
The bit assignments are:
•PRI_7
Reserved
•PRI_6
Priority of system handler 6, usage fault
•PRI_5
Priority of system handler 5, bus fault
•PRI_4
Priority of system handler 4, memory management fault
3130292827 26 25 24
PRI_7: Reserved
2322 21 20 19 1817 16
PRI_6
15 14 1312 11 10 9 8
PRI_5
76543210
PRI_4
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10.21.9.2 System Handler Priority Register 2
The bit assignments are:
•PRI_11
Priority of system handler 11, SVCall
10.21.9.3 System Handler Priority Register 3
The bit assignments are:
•PRI_15
Priority of system handler 15, SysTick exception
•PRI_14
Priority of system handler 14, PendSV
3130292827 26 25 24
PRI_11
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
Reserved
3130292827 26 25 24
PRI_15
2322 21 20 19 1817 16
PRI_14
15 14 1312 11 10 9 8
Reserved
76543210
Reserved
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10.21.10 System Handler Control and State Register
The SHCSR enables the system handlers, and indicates:
the pending status of the bus fault, memory management fault, and SVC exceptions
the active status of the system handlers.
See the register summary in Table 10-30 on page 165 for the SHCSR attributes. The bit assignments are:
• USGFAULTENA
Usage fault enable bit, set to 1 to enable (1)
• BUSFAULTENA
Bus fault enable bit, set to 1 to enable(3)
•MEMFAULTENA
Memory management fault enable bit, set to 1 to enable(3)
• SVCALLPENDED
SVC call pending bit, reads as 1 if exception is pending (2)
• BUSFAULTPENDED
Bus fault exception pending bit, reads as 1 if exception is pending(2)
• MEMFAULTPENDED
Memory management fault exception pending bit, reads as 1 if exception is pending(2)
• USGFAULTPENDED
Usage fault exception pending bit, reads as 1 if exception is pending(2)
• SYSTICKACT
SysTick exception active bit, reads as 1 if exception is active (3)
• PENDSVACT
PendSV exception active bit, reads as 1 if exception is active
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved USGFAULTENA BUSFAULTENA MEMFAULTENA
15 14 1312 11 10 9 8
SVCALLPENDE
DBUSFAULTPEND
ED MEMFAULTPEN
DED USGFAULTPEND
ED SYSTICKACT PENDSVACT Reserved MONITORACT
76543210
SVCALLAVCT Reserved USGFAULTACT Reserved BUSFAULTACT MEMFAULTACT
1. Enable bits, set to 1 to enable the exception, or set to 0 to disable the exception.
2. Pending bits, read as 1 if the exception is pending, or as 0 if it is not pending. You can write to these bits to change the pending
status of the exceptions.
3. Active bits, read as 1 if the exception is active, or as 0 if it is not active. You can write to these bits to change the active status of
the exceptions, but see the Caution in this section.
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• MONITORACT
Debug monitor active bit, reads as 1 if Debug monitor is active
• SVCALLACT
SVC call active bit, reads as 1 if SVC call is active
• USGFAULTACT
Usage fault exception active bit, reads as 1 if exception is active
• BUSFAULTACT
Bus fault exception active bit, reads as 1 if exception is active
• MEMFAULTACT
Memory management fault exception active bit, reads as 1 if exception is active
If you disable a system handler and the corresponding fault occurs, the processor treats the fault as a hard fault.
You can write to this register to change the pending or active status of system exceptions. An OS kernel can write to the
active bits to perform a context switch that changes the current exception type.
•Software that changes the value of an active bit in this register without correct adjustment to the stacked content can
cause the processor to generate a fault exception. Ensure software that writes to this register retains and subsequently
restores the current active status.
•A
f
ter you have enabled the system handlers, if you have to change the value of a bit in this register you must use a
read-modify-write procedure to ensure that you change only the required bit.
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10.21.11 Configurable Fault Status Register
The CFSR indicates the cause of a memory management fault, bus fault, or usage fault. See the register summary
in Table 10-30 on page 165 for its attributes. The bit assignments are:
The following subsections describe the subregisters that make up the CFSR:
“Memory Management Fault Status Register” on page 183
“Bus Fault Status Register” on page 184
“Usage Fault Status Register” on page 186.
The CFSR is byte accessible. You can access the CFSR or its subregisters as follows:
access the complete CFSR with a word access to 0xE000ED28
access the MMFSR with a byte access to 0xE000ED28
access the MMFSR and BFSR with a halfword access to 0xE000ED28
access the BFSR with a byte access to 0xE000ED29
access the UFSR with a halfword access to 0xE000ED2A.
3130292827 26 25 24
Usage Fault Status Register: UFSR
2322 21 20 19 1817 16
Usage Fault Status Register: UFSR
15 14 1312 11 10 9 8
Bus Fault Status Register: BFSR
76543210
Memory Management Fault Status Register: MMFSR
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10.21.11.1 Memory Management Fault Status Register
The flags in the MMFSR indicate the cause of memory access faults. The bit assignments are:
• MMARVALID
Memory Management Fault Address Register (MMAR) valid flag:
0: value in MMAR is not a valid fault address
1: MMAR holds a valid fault address.
If a memory management fault occurs and is escalated to a hard fault because of priority, the hard fault handler must set
this bit to 0. This prevents problems on return to a stacked active memory management fault handler whose MMAR value
has been overwritten.
•MSTKERR
Memory manager fault on stacking for exception entry:
0: no stacking fault
1: stacking for an exception entry has caused one or more access violations.
When this bit is 1, the SP is still adjusted but the values in the context area on the stack might be incorrect. The processor
has not written a fault address to the MMAR.
• MUNSTKERR
Memory manager fault on unstacking for a return from exception:
0: no unstacking fault
1: unstack for an exception return has caused one or more access violations.
This fault is chained to the handler. This means that when this bit is 1, the original return stack is still present. The proces-
sor has not adjusted the SP from the failing return, and has not performed a new save. The processor has not written a
fault address to the MMAR.
• DACCVIOL
Data access violation flag:
0: no data access violation fault
1: the processor attempted a load or store at a location that does not permit the operation.
When this bit is 1, the PC value stacked for the exception return points to the faulting instruction. The processor has loaded
the MMAR with the address of the attempted access.
• IACCVIOL
Instruction access violation flag:
0: no instruction access violation fault
1: the processor attempted an instruction fetch from a location that does not permit execution.
This fault occurs on any access to an XN region, even when the MPU is disabled or not present.
When this bit is 1, the PC value stacked for the exception return points to the faulting instruction. The processor has not
written a fault address to the MMAR.
76543210
MMARVALID Reserved MSTKERR MUNSTKERR Reserved DACCVIOL IACCVIOL
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10.21.11.2 Bus Fault Status Register
The flags in the BFSR indicate the cause of a bus access fault. The bit assignments are:
•BFARVALID
Bus Fault Address Register (BFAR) valid flag:
0: value in BFAR is not a valid fault address
1: BFAR holds a valid fault address.
The processor sets this bit to 1 after a bus fault where the address is known. Other faults can set this bit to 0, such as a
memory management fault occurring later.
If a bus fault occurs and is escalated to a hard fault because of priority, the hard fault handler must set this bit to 0. This
prevents problems if returning to a stacked active bus fault handler whose BFAR value has been overwritten.
•STKERR
Bus fault on stacking for exception entry:
0: no stacking fault
1: stacking for an exception entry has caused one or more bus faults.
When the processor sets this bit to 1, the SP is still adjusted but the values in the context area on the stack might be incor-
rect. The processor does not write a fault address to the BFAR.
•UNSTKERR
Bus fault on unstacking for a return from exception:
0: no unstacking fault
1: unstack for an exception return has caused one or more bus faults.
This fault is chained to the handler. This means that when the processor sets this bit to 1, the original return stack is still
present. The processor does not adjust the SP from the failing return, does not performed a new save, and does not write
a fault address to the BFAR.
• IMPRECISERR
Imprecise data bus error:
0: no imprecise data bus error
1: a data bus error has occurred, but the return address in the stack frame is not related to the instruction that caused the
error.
When the processor sets this bit to 1, it does not write a fault address to the BFAR.
This is an asynchronous fault. Therefore, if it is detected when the priority of the current process is higher than the bus fault
priority, the bus fault becomes pending and becomes active only when the processor returns from all higher priority pro-
cesses. If a precise fault occurs before the processor enters the handler for the imprecise bus fault, the handler detects
both IMPRECISERR set to 1 and one of the precise fault status bits set to 1.
76543210
BFRVALID Reserved STKERR UNSTKERR IMPRECISERR PRECISERR IBUSERR
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• PRECISERR
Precise data bus error:
0: no precise data bus error
1: a data bus error has occurred, and the PC value stacked for the exception return points to the instruction that caused the
fault.
When the processor sets this bit is 1, it writes the faulting address to the BFAR.
• IBUSERR
Instruction bus error:
0: no instruction bus error
1: instruction bus error.
The processor detects the instruction bus error on prefetching an instruction, but it sets the IBUSERR flag to 1 only if it
attempts to issue the faulting instruction.
When the processor sets this bit is 1, it does not write a fault address to the BFAR.
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10.21.11.3 Usage Fault Status Register
The UFSR indicates the cause of a usage fault. The bit assignments are:
• DIVBYZERO
Divide by zero usage fault:
0: no divide by zero fault, or divide by zero trapping not enabled
1: the processor has executed an SDIV or UDIV instruction with a divisor of 0.
When the processor sets this bit to 1, the PC value stacked for the exception return points to the instruction that performed
the divide by zero.
Enable trapping of divide by zero by setting the DIV_0_TRP bit in the CCR to 1, see “Configuration and Control Register”
on page 175.
•UNALIGNED
Unaligned access usage fault:
0: no unaligned access fault, or unaligned access trapping not enabled
1: the processor has made an unaligned memory access.
Enable trapping of unaligned accesses by setting the UNALIGN_TRP bit in the CCR to 1, see “Configuration and Control
Register” on page 175.
Unaligned LDM, STM, LDRD, and STRD instructions always fault irrespective of the setting of UNALIGN_TRP.
•NOCP
No coprocessor usage fault. The processor does not support coprocessor instructions:
0: no usage fault caused by attempting to access a coprocessor
1: the processor has attempted to access a coprocessor.
• INVPC
Invalid PC load usage fault, caused by an invalid PC load by EXC_RETURN:
0: no invalid PC load usage fault
1: the processor has attempted an illegal load of EXC_RETURN to the PC, as a result of an invalid context, or an invalid
EXC_RETURN value.
When this bit is set to 1, the PC value stacked for the exception return points to the instruction that tried to perform the ille-
gal load of the PC.
• INVSTATE
Invalid state usage fault:
0: no invalid state usage fault
1: the processor has attempted to execute an instruction that makes illegal use of the EPSR.
When this bit is set to 1, the PC value stacked for the exception return points to the instruction that attempted the illegal
use of the EPSR.
This bit is not set to 1 if an undefined instruction uses the EPSR.
15 14 1312 11 10 9 8
Reserved DIVBYZERO UNALIGNED
76543210
Reserved NOCP INVPC INVSTATE UNDEFINSTR
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• UNDEFINSTR
Undefined instruction usage fault:
0: no undefined instruction usage fault
1: the processor has attempted to execute an undefined instruction.
When this bit is set to 1, the PC value stacked for the exception return points to the undefined instruction.
An undefined instruction is an instruction that the processor cannot decode.
The UFSR bits are sticky. This means as one or more fault occurs, the associated bits are set to 1. A bit that is set to 1 is
cleared to 0 only by writing 1 to that bit, or by a reset.
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10.21.12 Hard Fault Status Register
The HFSR gives information about events that activate the hard fault handler. See the register summary in Table
10-30 on page 165 for its attributes.
This register is read, write to clear. This means that bits in the register read normally, but writing 1 to any bit clears
that bit to 0. The bit assignments are:
• DEBUGEVT
Reserved for Debug use. When writing to the register you must write 0 to this bit, otherwise behavior is Unpredictable.
• FORCED
Indicates a forced hard fault, generated by escalation of a fault with configurable priority that cannot be handles, either
because of priority or because it is disabled:
0: no forced hard fault
1: forced hard fault.
When this bit is set to 1, the hard fault handler must read the other fault status registers to find the cause of the fault.
• VECTTBL
Indicates a bus fault on a vector table read during exception processing:
0: no bus fault on vector table read
1: bus fault on vector table read.
This error is always handled by the hard fault handler.
When this bit is set to 1, the PC value stacked for the exception return points to the instruction that was preempted by the
exception.
The HFSR bits are sticky. This means as one or more fault occurs, the associated bits are set to 1. A bit that is set to 1 is
cleared to 0 only by writing 1 to that bit, or by a reset.
3130292827 26 25 24
DEBUGEVT FORCED Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
Reserved VECTTBL Reserved
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10.21.13 Memory Management Fault Address Register
The MMFAR contains the address of the location that generated a memory management fault. See the register
summary in Table 10-30 on page 165 for its attributes. The bit assignments are:
• ADDRESS
When the MMARVALID bit of the MMFSR is set to 1, this field holds the address of the location that generated the memory
management fault
When an unaligned access faults, the address is the actual address that faulted. Because a single read or write instruction
can be split into multiple aligned accesses, the fault address can be any address in the range of the requested access size.
Flags in the MMFSR indicate the cause of the fault, and whether the value in the MMFAR is valid. See “Memory Manage-
ment Fault Status Register” on page 183.
3130292827 26 25 24
ADDRESS
2322 21 20 19 1817 16
ADDRESS
15 14 1312 11 10 9 8
ADDRESS
76543210
ADDRESS
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10.21.14 Bus Fault Address Register
The BFAR contains the address of the location that generated a bus fault. See the register summary in Table 10-
30 on page 165 for its attributes. The bit assignments are:
• ADDRESS
When the BFARVALID bit of the BFSR is set to 1, this field holds the address of the location that generated the bus fault
When an unaligned access faults the address in the BFAR is the one requested by the instruction, even if it is not the
address of the fault.
Flags in the BFSR indicate the cause of the fault, and whether the value in the BFAR is valid. See “Bus Fault Status Regis-
ter” on page 184.
3130292827 26 25 24
ADDRESS
2322 21 20 19 1817 16
ADDRESS
15 14 1312 11 10 9 8
ADDRESS
76543210
ADDRESS
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10.21.15 System control block design hints and tips
Ensure software uses aligned accesses of the correct size to access the system control block registers:
except for the CFSR and SHPR1-SHPR3, it must use aligned word accesses
for the CFSR and SHPR1-SHPR3 it can use byte or aligned halfword or word accesses.
The processor does not support unaligned accesses to system control block registers.
In a fault handler. to determine the true faulting address:
Read and save the MMFAR or BFAR value.
Read the MMARVALID bit in the MMFSR, or the BFARVALID bit in the BFSR. The MMFAR or BFAR address
is valid only if this bit is 1.
Software must follow this sequence because another higher priority exception might change the MMFAR or BFAR
value. For example, if a higher priority handler preempts the current fault handler, the other fault might change the
MMFAR or BFAR value.
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10.22 System timer, SysTick
The processor has a 24-bit system timer, SysTick, that counts down from the reload value to zero, reloads (wraps
to) the value in the LOAD register on the next clock edge, then counts down on subsequent clocks.
When the processor is halted for debugging the counter does not decrement.
The system timer registers are:
Table 10-33. System timer registers summary
Address Name Type Required
privilege Reset
value Description
0xE000E010 CTRL RW Privileged 0x00000004 “SysTick Control and Status Register” on page 193
0xE000E014 LOAD RW Privileged 0x00000000 “SysTick Reload Value Register” on page 194
0xE000E018 VAL RW Privileged 0x00000000 “SysTick Current Value Register” on page 195
0xE000E01C CALIB RO Privileged 0x0002904 (1) “SysTick Calibration Value Register” on page 196
1. SysTick calibration value.
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10.22.1 SysTick Control and Status Register
The SysTick CTRL register enables the SysTick features. See the register summary in Table 10-33 on page 192
for its attributes. The bit assignments are:
• COUNTFLAG
Returns 1 if timer counted to 0 since last time this was read.
• CLKSOURCE
Indicates the clock source:
0: MCK/8
1: MCK
• TICKINT
Enables SysTick exception request:
0: counting down to zero does not assert the SysTick exception request
1: counting down to zero to asserts the SysTick exception request.
Software can use COUNTFLAG to determine if SysTick has ever counted to zero.
• ENABLE
Enables the counter:
0: counter disabled
1: counter enabled.
When ENABLE is set to 1, the counter loads the RELOAD value from the LOAD register and then counts down. On reach-
ing 0, it sets the COUNTFLAG to 1 and optionally asserts the SysTick depending on the value of TICKINT. It then loads the
RELOAD value again, and begins counting.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved COUNTFLAG
15 14 1312 11 10 9 8
Reserved
76543210
Reserved CLKSOURCE TICKINT ENABLE
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10.22.2 SysTick Reload Value Register
The LOAD register specifies the start value to load into the VAL register. See the register summary in Table 10-33
on page 192 for its attributes. The bit assignments are:
•RELOAD
Value to load into the VAL register when the counter is enabled and when it reaches 0, see “Calculating the RELOAD
value” .
10.22.2.1 Calculating the RELOAD value
The RELOAD value can be any value in the range 0x00000001-0x00FFFFFF. A start value of 0 is possible, but
has no effect because the SysTick exception request and COUNTFLAG are activated when counting from 1 to 0.
The RELOAD value is calculated according to its use:
To generate a multi-shot timer with a period of N processor clock cycles, use a RELOAD value of N-1. For
example, if the SysTick interrupt is required every 100 clock pulses, set RELOAD to 99.
To deliver a single SysTick interrupt after a delay of N processor clock cycles, use a RELOAD of value N. For
example, if a SysTick interrupt is required after 400 clock pulses, set RELOAD to 400.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
RELOAD
15 14 1312 11 10 9 8
RELOAD
76543210
-RELOAD
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10.22.3 SysTick Current Value Register
The VAL register contains the current value of the SysTick counter. See the register summary in Table 10-33 on
page 192 for its attributes. The bit assignments are:
• CURRENT
Reads return the current value of the SysTick counter.
A write of any value clears the field to 0, and also clears the SysTick CTRL.COUNTFLAG bit to 0.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
CURRENT
15 14 1312 11 10 9 8
CURRENT
76543210
CURRENT
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10.22.4 SysTick Calibration Value Register
The CALIB register indicates the SysTick calibration properties. See the register summary in Table 10-33 on page
192 for its attributes. The bit assignments are:
•NOREF
Reads as zero.
•SKEW
Reads as zero
•TENMS
Read as 0x0002904. The SysTick calibration value is fixed at 0x0002904 (10500), which allows the generation of a time
base of 1 ms with SysTick clock at 10.5 MHz (84/8 = 10.5 MHz)
10.22.5 SysTick design hints and tips
The SysTick counter runs on the processor clock. If this clock signal is stopped for low power mode, the SysTick
counter stops.
Ensure software uses aligned word accesses to access the SysTick registers.
3130292827 26 25 24
NOREF SKEW Reserved
2322 21 20 19 1817 16
TENMS
15 14 1312 11 10 9 8
TENMS
76543210
TENMS
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10.23 Memory protection unit
This section describes the Memory protection unit (MPU).
The MPU divides the memory map into a number of regions, and defines the location, size, access permissions,
and memory attributes of each region. It supports:
independent attribute settings for each region
overlapping regions
export of memory attributes to the system.
The memory attributes affect the behavior of memory accesses to the region. The Cortex-M3 MPU defines:
eight separate memory regions, 0-7
a background region.
When memory regions overlap, a memory access is affected by the attributes of the region with the highest
number. For example, the attributes for region 7 take precedence over the attributes of any region that overlaps
region 7.
The background region has the same memory access attributes as the default memory map, but is accessible
from privileged software only.
The Cortex-M3 MPU memory map is unified. This means instruction accesses and data accesses have same
region settings.
If a program accesses a memory location that is prohibited by the MPU, the processor generates a memory
management fault. This causes a fault exception, and might cause termination of the process in an OS
environment.
In an OS environment, the kernel can update the MPU region setting dynamically based on the process to be
executed. Typically, an embedded OS uses the MPU for memory protection.
Configuration of MPU regions is based on memory types, see “Memory regions, types and attributes” on page 62.
Table 10-34 shows the possible MPU region attributes. These include Share ability and cache behavior attributes
that are not relevant to most microcontroller implementations. See “MPU configuration for a microcontroller” on
page 209 for guidelines for programming such an implementation.
Table 10-34. Memory attributes summary
Memory type Shareability Other attributes Description
Strongly- ordered - - All accesses to Strongly-ordered memory occur in program order.
All Strongly-ordered regions are assumed to be shared.
Device Shared - Memory-mapped peripherals that several processors share.
Non-shared - Memory-mapped peripherals that only a single processor uses.
Normal Shared Normal memory that is shared between several processors.
Non-shared Normal memory that only a single processor uses.
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Use the MPU registers to define the MPU regions and their attributes. The MPU registers are:
Table 10-35. MPU registers summary
Address Name Type Required
privilege Reset
value Description
0xE000ED90 TYPE RO Privileged 0x00000800 “MPU Type Register” on page 199
0xE000ED94 CTRL RW Privileged 0x00000000 “MPU Control Register” on page 200
0xE000ED98 RNR RW Privileged 0x00000000 “MPU Region Number Register” on page 202
0xE000ED9C RBAR RW Privileged 0x00000000 “MPU Region Base Address Register” on page 203
0xE000EDA0 RASR RW Privileged 0x00000000 “MPU Region Attribute and Size Register” on page 204
0xE000EDA4 RBAR_A1 RW Privileged 0x00000000 Alias of RBAR, see “MPU Region Base Address
Register” on page 203
0xE000EDA8 RASR_A1 RW Privileged 0x00000000 Alias of RASR, see “MPU Region Attribute and Size
Register” on page 204
0xE000EDAC RBAR_A2 RW Privileged 0x00000000 Alias of RBAR, see “MPU Region Base Address
Register” on page 203
0xE000EDB0 RASR_A2 RW Privileged 0x00000000 Alias of RASR, see “MPU Region Attribute and Size
Register” on page 204
0xE000EDB4 RBAR_A3 RW Privileged 0x00000000 Alias of RBAR, see “MPU Region Base Address
Register” on page 203
0xE000EDB8 RASR_A3 RW Privileged 0x00000000 Alias of RASR, see “MPU Region Attribute and Size
Register” on page 204
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10.23.1 MPU Type Register
The TYPE register indicates whether the MPU is present, and if so, how many regions it supports. See the register
summary in Table 10-35 on page 198 for its attributes. The bit assignments are:
• IREGION
Indicates the number of supported MPU instruction regions.
Always contains 0x00. The MPU memory map is unified and is described by the DREGION field.
• DREGION
Indicates the number of supported MPU data regions:
0x08 = Eight MPU regions.
• SEPARATE
Indicates support for unified or separate instruction and date memory maps:
0: unified.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
IREGION
15 14 1312 11 10 9 8
DREGION
76543210
Reserved SEPARATE
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10.23.2 MPU Control Register
The MPU CTRL register:
enables the MPU
enables the default memory map background region
enables use of the MPU when in the hard fault, Non-maskable Interrupt (NMI), and FAULTMASK escalated
handlers.
See the register summary in Table 10-35 on page 198 for the MPU CTRL attributes. The bit assignments are:
• PRIVDEFENA
Enables privileged software access to the default memory map:
0: If the MPU is enabled, disables use of the default memory map. Any memory access to a location not covered by any
enabled region causes a fault.
1: If the MPU is enabled, enables use of the default memory map as a background region for privileged software accesses.
When enabled, the background region acts as if it is region number -1. Any region that is defined and enabled has priority
over this default map.
If the MPU is disabled, the processor ignores this bit.
•HFNMIENA
Enables the operation of MPU during hard fault, NMI, and FAULTMASK handlers.
When the MPU is enabled:
0: MPU is disabled during hard fault, NMI, and FAULTMASK handlers, regardless of the value of the ENABLE bit
1: the MPU is enabled during hard fault, NMI, and FAULTMASK handlers.
When the MPU is disabled, if this bit is set to 1 the behavior is Unpredictable.
• ENABLE
Enables the MPU:
0: MPU disabled
1: MPU enabled.
When ENABLE and PRIVDEFENA are both set to 1:
For privileged accesses, the default memory map is as described in “Memory model” on page 62. Any access by privileged
software that does not address an enabled memory region behaves as defined by the default memory map.
Any access by unprivileged software that does not address an enabled memory region causes a memory management
fault.
XN and Strongly-ordered rules always apply to the System Control Space regardless of the value of the ENABLE bit.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
Reserved PRIVDEFENA HFNMIENA ENABLE
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When the ENABLE bit is set to 1, at least one region of the memory map must be enabled for the system to function unless
the PRIVDEFENA bit is set to 1. If the PRIVDEFENA bit is set to 1 and no regions are enabled, then only privileged soft-
ware can operate.
When the ENABLE bit is set to 0, the system uses the default memory map. This has the same memory attributes as if the
MPU is not implemented, see Table 10-34 on page 197. The default memory map applies to accesses from both privileged
and unprivileged software.
When the MPU is enabled, accesses to the System Control Space and vector table are always permitted. Other areas are
accessible based on regions and whether PRIVDEFENA is set to 1.
Unless HFNMIENA is set to 1, the MPU is not enabled when the processor is executing the handler for an exception with
priority –1 or –2. These priorities are only possible when handling a hard fault or NMI exception, or when FAULTMASK is
enabled. Setting the HFNMIENA bit to 1 enables the MPU when operating with these two priorities.
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10.23.3 MPU Region Number Register
The RNR selects which memory region is referenced by the RBAR and RASR registers. See the register summary
in Table 10-35 on page 198 for its attributes. The bit assignments are:
•REGION
Indicates the MPU region referenced by the RBAR and RASR registers.
The MPU supports 8 memory regions, so the permitted values of this field are 0-7.
Normally, you write the required region number to this register before accessing the RBAR or RASR. However you can
change the region number by writing to the RBAR with the VALID bit set to 1, see “MPU Region Base Address Register” on
page 203. This write updates the value of the REGION field.
3130292827 26 25 24
Reserved
2322 21 20 19 1817 16
Reserved
15 14 1312 11 10 9 8
Reserved
76543210
REGION
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10.23.4 MPU Region Base Address Register
The RBAR defines the base address of the MPU region selected by the RNR, and can update the value of the
RNR. See the register summary in Table 10-35 on page 198 for its attributes.
Write RBAR with the VALID bit set to 1 to change the current region number and update the RNR. The bit
assignments are:
•ADDR
Region base address field. The value of N depends on the region size. For more information see “The ADDR field” .
•VALID
MPU Region Number valid bit:
Write:
0: RNR not changed, and the processor:
updates the base address for the region specified in the RNR
ignores the value of the REGION field
1: the processor:
updates the value of the RNR to the value of the REGION field
updates the base address for the region specified in the REGION field.
Always reads as zero.
•REGION
MPU region field:
For the behavior on writes, see the description of the VALID field.
On reads, returns the current region number, as specified by the RNR.
10.23.4.1 The ADDR field
The ADDR field is bits[31:N] of the RBAR. The region size, as specified by the SIZE field in the RASR, defines the
value of N:
N = Log2(Region size in bytes),
If the region size is configured to 4GB, in the RASR, there is no valid ADDR field. In this case, the region occupies
the complete memory map, and the base address is 0x00000000.
The base address is aligned to the size of the region. For example, a 64KB region must be aligned on a multiple of
64KB, for example, at 0x00010000 or 0x00020000.
3130292827 26 25 24
ADDR
2322 21 20 19 1817 16
ADDR
15 14 1312 11 10 9 N
ADDR
N-16543210
Reserved VALID REGION
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10.23.5 MPU Region Attribute and Size Register
The RASR defines the region size and memory attributes of the MPU region specified by the RNR, and enables
that region and any subregions. See the register summary in Table 10-35 on page 198 for its attributes.
RASR is accessible using word or halfword accesses:
the most significant halfword holds the region attributes
the least significant halfword holds the region size and the region and subregion enable bits.
The bit assignments are:
•XN
Instruction access disable bit:
0: instruction fetches enabled
1: instruction fetches disabled.
•AP
Access permission field, see Table 10-39 on page 207.
• TEX, C, B
Memory access attributes, see Table 10-37 on page 206.
•S
Shareable bit, see Table 10-36 on page 205.
•SRD
Subregion disable bits. For each bit in this field:
0: corresponding sub-region is enabled
1: corresponding sub-region is disabled
See “Subregions” on page 208 for more information.
Region sizes of 128 bytes and less do not support subregions. When writing the attributes for such a region, write the SRD
field as 0x00.
•SIZE
Specifies the size of the MPU protection region. The minimum permitted value is 3 (b00010), see See “SIZE field values”
on page 205 for more information.
• ENABLE
Region enable bit.
For information about access permission, see “MPU access permission attributes” .
3130292827 26 25 24
Reserved XN Reserved AP
2322 21 20 19 1817 16
Reserved TEX SCB
15 14 1312 11 10 9 8
SRD
76543210
Reserved SIZE ENABLE
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10.23.5.1 SIZE field values
The SIZE field defines the size of the MPU memory region specified by the RNR. as follows:
(Region size in bytes) = 2(SIZE+1)
The smallest permitted region size is 32B, corresponding to a SIZE value of 4. Table 10-36 gives example SIZE
values, with the corresponding region size and value of N in the RBAR.
Table 10-36. Example SIZE field values
SIZE value Region size Value of N (1)
1. In the RBAR, see “MPU Region Base Address Register” on page 203.
Note
b00100 (4) 32B 5 Minimum permitted size
b01001 (9) 1KB 10 -
b10011 (19) 1MB 20 -
b11101 (29) 1GB 30 -
b11111 (31) 4GB b01100 Maximum possible size
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10.23.6 MPU access permission attributes
This section describes the MPU access permission attributes. The access permission bits, TEX, C, B, S, AP, and
XN, of the RASR, control access to the corresponding memory region. If an access is made to an area of memory
without the required permissions, then the MPU generates a permission fault.
Table 10-37 shows the encodings for the TEX, C, B, and S access permission bits.
Table 10-38 shows the cache policy for memory attribute encodings with a TEX value is in the range 4-7.
Table 10-37. TEX, C, B, and S encoding
TEX C B S Memory type Shareability Other attributes
b000
0
0 x (1)
1. The MPU ignores the value of this bit.
Strongly-ordered Shareable -
1 x(1) Device Shareable -
1
0 0Normal Not shareable Outer and inner write-through. No write allocate.
1 Shareable
1 0Normal Not shareable Outer and inner write-back. No write allocate.
1 Shareable
b001
0
0 0Normal Not shareable
1 Shareable
1 x(1) Reserved encoding -
1
0 x(1) Implementation defined attributes. -
1 0Normal Not shareable Outer and inner write-back. Write and read allocate.
1 Shareable
b010 00 x(1) Device Not shareable Nonshared Device.
1 x(1) Reserved encoding -
1x
(1) x(1) Reserved encoding -
b1BB A A 0Normal Not shareable
1Shareable
Table 10-38. Cache policy for memory attribute encoding
Encoding, AA or BB Corresponding cache policy
00 Non-cacheable
01 Write back, write and read allocate
10 Write through, no write allocate
11 Write back, no write allocate
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Table 10-39 shows the AP encodings that define the access permissions for privileged and unprivileged software.
10.23.7 MPU mismatch
When an access violates the MPU permissions, the processor generates a memory management fault, see
“Exceptions and interrupts” on page 61. The MMFSR indicates the cause of the fault. See “Memory Management
Fault Status Register” on page 183 for more information.
10.23.8 Updating an MPU region
To update the attributes for an MPU region, update the RNR, RBAR and RASR registers. You can program each
register separately, or use a multiple-word write to program all of these registers. You can use the RBAR and
RASR aliases to program up to four regions simultaneously using an STM instruction.
10.23.8.1 Updating an MPU region using separate words
Simple code to configure one region:
; R1 = region number
; R2 = size/enable
; R3 = attributes
; R4 = address
LDR R0,=MPU_RNR ; 0xE000ED98, MPU region number register
STR R1, [R0, #0x0] ; Region Number
STR R4, [R0, #0x4] ; Region Base Address
STRH R2, [R0, #0x8] ; Region Size and Enable
STRH R3, [R0, #0xA] ; Region Attribute
Disable a region before writing new region settings to the MPU if you have previously enabled the region being
changed. For example:
; R1 = region number
; R2 = size/enable
; R3 = attributes
; R4 = address
LDR R0,=MPU_RNR ; 0xE000ED98, MPU region number register
STR R1, [R0, #0x0] ; Region Number
BIC R2, R2, #1 ; Disable
STRH R2, [R0, #0x8] ; Region Size and Enable
STR R4, [R0, #0x4] ; Region Base Address
STRH R3, [R0, #0xA] ; Region Attribute
ORR R2, #1 ; Enable
STRH R2, [R0, #0x8] ; Region Size and Enable
Table 10-39. AP encoding
AP[2:0]
Privileged
permissions
Unprivileged
permissions Description
000 No access No access All accesses generate a permission fault
001 RW No access Access from privileged software only
010 RW RO Writes by unprivileged software generate a permission fault
011 RW RW Full access
100 Unpredictable Unpredictable Reserved
101 RO No access Reads by privileged software only
110 RO RO Read only, by privileged or unprivileged software
111 RO RO Read only, by privileged or unprivileged software
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Software must use memory barrier instructions:
before MPU setup if there might be outstanding memory transfers, such as buffered writes, that might be
affected by the change in MPU settings
after MPU setup if it includes memory transfers that must use the new MPU settings.
However, memory barrier instructions are not required if the MPU setup process starts by entering an exception
handler, or is followed by an exception return, because the exception entry and exception return mechanism cause
memory barrier behavior.
Software does not need any memory barrier instructions during MPU setup, because it accesses the MPU through
the PPB, which is a Strongly-Ordered memory region.
For example, if you want all of the memory access behavior to take effect immediately after the programming
sequence, use a DSB instruction and an ISB instruction. A DSB is required after changing MPU settings, such as
at the end of context switch. An ISB is required if the code that programs the MPU region or regions is entered
using a branch or call. If the programming sequence is entered using a return from exception, or by taking an
exception, then you do not require an ISB.
10.23.8.2 Updating an MPU region using multi-word writes
You can program directly using multi-word writes, depending on how the information is divided. Consider the
following reprogramming:
; R1 = region number
; R2 = address
; R3 = size, attributes in one
LDR R0, =MPU_RNR ; 0xE000ED98, MPU region number register
STR R1, [R0, #0x0] ; Region Number
STR R2, [R0, #0x4] ; Region Base Address
STR R3, [R0, #0x8] ; Region Attribute, Size and Enable
Use an STM instruction to optimize this:
; R1 = region number
; R2 = address
; R3 = size, attributes in one
LDR R0, =MPU_RNR ; 0xE000ED98, MPU region number register
STM R0, {R1-R3} ; Region Number, address, attribute, size and enable
You can do this in two words for pre-packed information. This means that the RBAR contains the required region
number and had the VALID bit set to 1, see “MPU Region Base Address Register” on page 203. Use this when the
data is statically packed, for example in a boot loader:
; R1 = address and region number in one
; R2 = size and attributes in one
LDR R0, =MPU_RBAR ; 0xE000ED9C, MPU Region Base register
STR R1, [R0, #0x0] ; Region base address and
; region number combined with VALID (bit 4) set to 1
STR R2, [R0, #0x4] ; Region Attribute, Size and Enable
Use an STM instruction to optimize this:
; R1 = address and region number in one
; R2 = size and attributes in one
LDR R0,=MPU_RBAR ; 0xE000ED9C, MPU Region Base register
STM R0, {R1-R2} ; Region base address, region number and VALID bit,
; and Region Attribute, Size and Enable
10.23.8.3 Subregions
Regions of 256 bytes or more are divided into eight equal-sized subregions. Set the corresponding bit in the SRD
field of the RASR to disable a subregion, see “MPU Region Attribute and Size Register” on page 204. The least
significant bit of SRD controls the first subregion, and the most significant bit controls the last subregion. Disabling
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a subregion means another region overlapping the disabled range matches instead. If no other enabled region
overlaps the disabled subregion the MPU issues a fault.
Regions of 32, 64, and 128 bytes do not support subregions, With regions of these sizes, you must set the SRD
field to 0x00, otherwise the MPU behavior is Unpredictable.
10.23.8.4 Example of SRD use
Two regions with the same base address overlap. Region one is 128KB, and region two is 512KB. To ensure the
attributes from region one apply to the first128KB region, set the SRD field for region two to b00000011 to disable
the first two subregions, as Figure 10-9 shows
Figure 10-9. SRD use
10.23.9 MPU design hints and tips
To avoid unexpected behavior, disable the interrupts before updating the attributes of a region that the interrupt
handlers might access.
Ensure software uses aligned accesses of the correct size to access MPU registers:
except for the RASR, it must use aligned word accesses
for the RASR it can use byte or aligned halfword or word accesses.
The processor does not support unaligned accesses to MPU registers.
When setting up the MPU, and if the MPU has previously been programmed, disable unused regions to prevent
any previous region settings from affecting the new MPU setup.
10.23.9.1 MPU configuration for a microcontroller
Usually, a microcontroller system has only a single processor and no caches. In such a system, program the MPU
as follows:
In most microcontroller implementations, the share ability and cache policy attributes do not affect the system
behavior. However, using these settings for the MPU regions can make the application code more portable. The
values given are for typical situations. In special systems, such as multiprocessor designs or designs with a
separate DMA engine, the share ability attribute might be important. In these cases refer to the recommendations
of the memory device manufacturer.
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Table 10-40. Memory region attributes for a microcontroller
Memory region TEX C B S Memory type and attributes
Flash memory b000 1 0 0 Normal memory, Non-shareable, write-through
Internal SRAM b000 1 0 1 Normal memory, Shareable, write-through
External SRAM b000 1 1 1 Normal memory, Shareable, write-back, write-allocate
Peripherals b000 0 1 1 Device memory, Shareable
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10.24 Glossary
This glossary describes some of the terms used in technical documents from ARM.
Abort
A mechanism that indicates to a processor that the value associated with a memory access is invalid. An abort can
be caused by the external or internal memory system as a result of attempting to access invalid instruction or data
memory.
Aligned
A data item stored at an address that is divisible by the number of bytes that defines the data size is said to be
aligned. Aligned words and halfwords have addresses that are divisible by four and two respectively. The terms
word-aligned and halfword-aligned therefore stipulate addresses that are divisible by four and two respectively.
Banked register
A register that has multiple physical copies, where the state of the processor determines which copy is used. The
Stack Pointer, SP (R13) is a banked register.
Base register
In instruction descriptions, a register specified by a load or store instruction that is used to hold the base value for
the instruction’s address calculation. Depending on the instruction and its addressing mode, an offset can be
added to or subtracted from the base register value to form the address that is sent to memory.
See also “Index register”
Breakpoint
A breakpoint is a mechanism provided by debuggers to identify an instruction at which program execution is to be
halted. Breakpoints are inserted by the programmer to enable inspection of register contents, memory locations,
variable values at fixed points in the program execution to test that the program is operating correctly. Breakpoints
are removed after the program is successfully tested.
Condition field
A four-bit field in an instruction that specifies a condition under which the instruction can execute.
Conditional execution
If the condition code flags indicate that the corresponding condition is true when the instruction starts executing, it
executes normally. Otherwise, the instruction does nothing.
Context
The environment that each process operates in for a multitasking operating system. In ARM processors, this is
limited to mean the physical address range that it can access in memory and the associated memory access
permissions.
Coprocessor
A processor that supplements the main processor. Cortex-M3 does not support any coprocessors.
Debugger
A debugging system that includes a program, used to detect, locate, and correct software faults, together with
custom hardware that supports software debugging.
Direct Memory Access (DMA)
An operation that accesses main memory directly, without the processor performing any accesses to the data
concerned.
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Doubleword
A 64-bit data item. The contents are taken as being an unsigned integer unless otherwise stated.
Doubleword-aligned
A data item having a memory address that is divisible by eight.
Endianness
Byte ordering. The scheme that determines the order that successive bytes of a data word are stored in memory.
An aspect of the system’s memory mapping.
See also “Little-endian (LE)”
Exception
An event that interrupts program execution. When an exception occurs, the processor suspends the normal
program flow and starts execution at the address indicated by the corresponding exception vector. The indicated
address contains the first instruction of the handler for the exception.
An exception can be an interrupt request, a fault, or a software-generated system exception. Faults include
attempting an invalid memory access, attempting to execute an instruction in an invalid processor state, and
attempting to execute an undefined instruction.
Exception service routine
See “Interrupt handler”
Exception vector
See “Interrupt vector”
Flat address mapping
A system of organizing memory in which each physical address in the memory space is the same as the
corresponding virtual address.
Halfword
A 16-bit data item.
Illegal instruction
An instruction that is architecturally Undefined.
Implementation-defined
The behavior is not architecturally defined, but is defined and documented by individual implementations.
Implementation-specific
The behavior is not architecturally defined, and does not have to be documented by individual implementations.
Used when there are a number of implementation options available and the option chosen does not affect software
compatibility.
Index register
In some load and store instruction descriptions, the value of this register is used as an offset to be added to or
subtracted from the base register value to form the address that is sent to memory. Some addressing modes
optionally enable the index register value to be shifted prior to the addition or subtraction.
See also “Base register”
Instruction cycle count
The number of cycles that an instruction occupies the Execute stage of the pipeline.
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Interrupt handler
A program that control of the processor is passed to when an interrupt occurs.
Interrupt vector
One of a number of fixed addresses in low memory, or in high memory if high vectors are configured, that contains
the first instruction of the corresponding interrupt handler.
Little-endian (LE)
Byte ordering scheme in which bytes of increasing significance in a data word are stored at increasing addresses
in memory.
See also “Little-endian memory” , “Endianness”
Little-endian memory
Memory in which:
a byte or halfword at a word-aligned address is the least significant byte or halfword within the word at that address
a byte at a halfword-aligned address is the least significant byte within the halfword at that address.
Load/store architecture
A processor architecture where data-processing operations only operate on register contents, not directly on
memory contents.
Memory Protection Unit (MPU)
Hardware that controls access permissions to blocks of memory. An MPU does not perform any address
translation.
Prefetching
In pipelined processors, the process of fetching instructions from memory to fill up the pipeline before the
preceding instructions have finished executing. Prefetching an instruction does not mean that the instruction has to
be executed.
Read
Reads are defined as memory operations that have the semantics of a load. Reads include the Thumb instructions
LDM, LDR, LDRSH, LDRH, LDRSB, LDRB, and POP.
Region
A partition of memory space.
Reserved
A field in a control register or instruction format is reserved if the field is to be defined by the implementation, or
produces Unpredictable results if the contents of the field are not zero. These fields are reserved for use in future
extensions of the architecture or are implementation-specific. All reserved bits not used by the implementation
must be written as 0 and read as 0.
Should Be One (SBO)
Write as 1, or all 1s for bit fields, by software. Writing as 0 produces Unpredictable results.
Should Be Zero (SBZ)
Write as 0, or all 0s for bit fields, by software. Writing as 1 produces Unpredictable results.
Should Be Zero or Preserved (SBZP)
Write as 0, or all 0s for bit fields, by software, or preserved by writing the same value back that has been previously
read from the same field on the same processor.
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Thread-safe
In a multi-tasking environment, thread-safe functions use safeguard mechanisms when accessing shared
resources, to ensure correct operation without the risk of shared access conflicts.
Thumb instruction
One or two halfwords that specify an operation for a processor to perform. Thumb instructions must be halfword-
aligned.
Unaligned
A data item stored at an address that is not divisible by the number of bytes that defines the data size is said to be
unaligned. For example, a word stored at an address that is not divisible by four.
Undefined
Indicates an instruction that generates an Undefined instruction exception.
Unpredictable (UNP)
You cannot rely on the behavior. Unpredictable behavior must not represent security holes. Unpredictable
behavior must not halt or hang the processor, or any parts of the system.
Warm reset
Also known as a core reset. Initializes the majority of the processor excluding the debug controller and debug
logic. This type of reset is useful if you are using the debugging features of a processor.
Word
A 32-bit data item.
Write
Writes are defined as operations that have the semantics of a store. Writes include the Thumb instructions STM,
STR, STRH, STRB, and PUSH.
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11. Debug and Test Features
11.1 Description
The SAM3 Series microcontrollers feature a number of complementary debug and test capabilities. The Serial
Wire/JTAG Debug Port (SWJ-DP) combining a Serial Wire Debug Port (SW-DP) and JTAG Debug (JTAG-DP) port
is used for standard debugging functions, such as downloading code and single-stepping through programs. It also
embeds a serial wire trace.
11.2 Embedded Characteristics
Debug access to all memory and registers in the system, including Cortex-M3 register bank when the core is
running, halted, or held in reset.
Serial Wire Debug Port (SW-DP) and Serial Wire JTAG Debug Port (SWJ-DP) debug access
Flash Patch and Breakpoint (FPB) unit for implementing breakpoints and code patches
Data Watchpoint and Trace (DWT) unit for implementing watchpoints, data tracing, and system profiling
Instrumentation Trace Macrocell (ITM) for support of printf style debugging
IEEE1149.1 JTAG Boundary-scan on all digital pins
Figure 11-1. Debug and Test Block Diagram
TST
TMS
TCK/SWCLK
TDI
JTAGSEL
TDO/TRACESWO
Boundary
TAP
SWJ-DP
Reset
and
Test
POR
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11.3 Application Examples
11.3.1 Debug Environment
Figure 11-2 shows a complete debug environment example. The SWJ-DP interface is used for standard
debugging functions, such as downloading code and single-stepping through the program and viewing core and
peripheral registers.
Figure 11-2. Application Debug Environment Example
11.3.2 Test Environment
Figure 11-3 shows a test environment example (JTAG Boundary scan). Test vectors are sent and interpreted by
the tester. In this example, the “board in test” is designed using a number of JTAG-compliant devices. These
devices can be connected to form a single scan chain.
SAM3
Host Debugger
PC
SAM3-based Application Board
SWJ-DP
Connector
SWJ-DP
Emulator/Probe
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Figure 11-3. Application Test Environment Example
11.4 Debug and Test Pin Description
Note: 1. TDO pin is set in input mode when the Cortex-M3 Core is not in debug mode. Thus the internal pull-up
corresponding to this PIO line must be enabled to avoid current consumption due to floating input.
Chip 2
Chip n
Chip 1
SAM3
SAM3-based Application Board In Test
JTAG
Connector
Tester
Test Adaptor
JTAG
Probe
Table 11-1. Debug and Test Signal List
Signal Name Function Type Active Level
Reset/Test
NRST Microcontroller Reset Input/Output Low
TST Test Select Input
SWD/JTAG
TCK/SWCLK Test Clock/Serial Wire Clock Input
TDI Test Data In Input
TDO/TRACESWO Test Data Out/Trace Asynchronous Data Out Output (1)
TMS/SWDIO Test Mode Select/Serial Wire Input/Output Input
JTAGSEL JTAG Selection Input High
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11.5 Functional Description
11.5.1 Test Pin
One dedicated pin, TST, is used to define the device operating mode. When this pin is at low level during power-
up, the device is in normal operating mode. When at high level, the device is in test mode or FFPI mode. The TST
pin integrates a permanent pull-down resistor of about 15 kΩ,so that it can be left unconnected for normal
operation. Note that when setting the TST pin to low or high level at power up, it must remain in the same state
during the duration of the whole operation.
11.5.2 Debug Architecture
Figure 11-4 shows the SAM3 debug architecture. The Cortex-M3 embeds five functional units for debug:
SWJ-DP (Serial Wire/JTAG Debug Port)
FPB (Flash Patch Breakpoint)
DWT (Data Watchpoint and Trace)
ITM (Instrumentation Trace Macrocell)
TPIU (Trace Port Interface Unit)
The debug architecture information that follows is mainly dedicated to developers of SWJ-DP Emulators/Probes
and debugging tool vendors for Cortex M3-based microcontrollers. For further details on SWJ-DP see the Cortex
M3 technical reference manual.
Figure 11-4. Debug Architecture
11.5.3 Serial Wire/JTAG Debug Port (SWJ-DP)
The Cortex-M3 embeds a SWJ-DP Debug port which is the standard CoreSight™ debug port. It combines Serial
Wire Debug Port (SW-DP), from 2 to 3 pins and JTAG debug Port (JTAG-DP), 5 pins.
By default, the JTAG Debug Port is active. If the host debugger wants to switch to the Serial Wire Debug Port, it
must provide a dedicated JTAG sequence on TMS/SWDIO and TCK/SWCLK which disables JTAG-DP and
enables SW-DP.
When the Serial Wire Debug Port is active, TDO/TRACESWO can be used for trace. The asynchronous TRACE
output (TRACESWO) is multiplexed with TDO. So the asynchronous trace can only be used with SW-DP, not
JTAG-DP.
4 watchpoints
PC sampler
data address sampler
data sampler
interrupt trace
CPU statistics
DWT
6 breakpoints
FPB
software trace
32 channels
time stamping
ITM
SWD/JTAG
SWJ-DP
SWO trace
TPIU
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SW-DP or JTAG-DP mode is selected when JTAGSEL is low. It is not possible to switch directly between SWJ-DP
and JTAG boundary scan operations. A chip reset must be performed after JTAGSEL is changed.
11.5.3.1 SW-DP and JTAG-DP Selection Mechanism
Debug port selection mechanism is done by sending specific SWDIOTMS sequence. The JTAG-DP is selected by
default after reset.
Switch from JTAG-DP to SW-DP. The sequence is:
̶Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1
̶Send the 16-bit sequence on SWDIOTMS = 0111100111100111 (0x79E7 MSB first)
̶Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1
Switch from SWD to JTAG. The sequence is:
̶Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1
̶Send the 16-bit sequence on SWDIOTMS = 0011110011100111 (0x3CE7 MSB first)
̶Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1
11.5.4 FPB (Flash Patch Breakpoint)
The FPB:
Implements hardware breakpoints
Patches code and data from code space to system space.
The FPB unit contains:
Two literal comparators for matching against literal loads from Code space, and remapping to a
corresponding area in System space.
Six instruction comparators for matching against instruction fetches from Code space and remapping to a
corresponding area in System space.
Alternatively, comparators can also be configured to generate a Breakpoint instruction to the processor core
on a match.
11.5.5 DWT (Data Watchpoint and Trace)
The DWT contains four comparators which can be configured to generate the following:
PC sampling packets at set intervals
PC or Data watchpoint packets
Watchpoint event to halt core
Table 11-2. SWJ-DP Pin List
Pin Name JTAG Port Serial Wire Debug Port
TMS/SWDIO TMS SWDIO
TCK/SWCLK TCK SWCLK
TDI TDI –
TDO/TRACESWO TDO TRACESWO (optional: trace)
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The DWT contains counters for the following items:
Clock cycle (CYCCNT)
Folded instructions
Load Store Unit (LSU) operations
Sleep Cycles
CPI (all instruction cycles except for the first cycle)
Interrupt overhead
11.5.6 ITM (Instrumentation Trace Macrocell)
The ITM is an application driven trace source that supports printf style debugging to trace Operating System (OS)
and application events, and emits diagnostic system information. The ITM emits trace information as packets
which can be generated by three different sources with several priority levels:
Software trace: Software can write directly to ITM stimulus registers. This can be done thanks to the “printf”
function. For more information, refer to Section 11.5.6.1 “How to Configure the ITM”.
Hardware trace: The ITM emits packets generated by the DWT.
Time stamping: Timestamps are emitted relative to packets. The ITM contains a 21-bit counter to generate
the timestamp.
11.5.6.1 How to Configure the ITM
The following example describes how to output trace data in asynchronous trace mode.
Configure the TPIU for asynchronous trace mode (refer to Section 11.5.6.3 “5.4.3. How to Configure the
TPIU”)
Enable the write accesses into the ITM registers by writing “0xC5ACCE55” into the Lock Access Register
(Address: 0xE0000FB0)
Write 0x00010015 into the Trace Control Register:
̶Enable ITM
̶Enable Synchronization packets
̶Enable SWO behavior
̶Fix the ATB ID to 1
Write 0x1 into the Trace Enable Register:
̶Enable the Stimulus port 0
Write 0x1 into the Trace Privilege Register:
̶Stimulus port 0 only accessed in privileged mode (Clearing a bit in this register will result in the
corresponding stimulus port being accessible in user mode.)
Write into the Stimulus port 0 register: TPIU (Trace Port Interface Unit)
The TPIU acts as a bridge between the on-chip trace data and the Instruction Trace Macrocell (ITM).
The TPIU formats and transmits trace data off-chip at frequencies asynchronous to the core.
11.5.6.2 Asynchronous Mode
The TPIU is configured in asynchronous mode, trace data are output using the single TRACESWO pin. The
TRACESWO signal is multiplexed with the TDO signal of the JTAG Debug Port. As a consequence, asynchronous
trace mode is only available when the Serial Wire Debug mode is selected since TDO signal is used in JTAG
debug mode.
Two encoding formats are available for the single pin output:
Manchester encoded stream. This is the reset value.
NRZ_based UART byte structure
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11.5.6.3 5.4.3. How to Configure the TPIU
This example only concerns the asynchronous trace mode.
Set the TRCENA bit to 1 into the Debug Exception and Monitor Register (0xE000EDFC) to enable the use of
trace and debug blocks.
Write 0x2 into the Selected Pin Protocol Register
̶Select the Serial Wire Output – NRZ
Write 0x100 into the Formatter and Flush Control Register
Set the suitable clock prescaler value into the Async Clock Prescaler Register to scale the baud rate of the
asynchronous output (this can be done automatically by the debugging tool).
11.5.7 IEEE® 1149.1 JTAG Boundary Scan
IEEE 1149.1 JTAG Boundary Scan allows pin-level access independent of the device packaging technology.
IEEE 1149.1 JTAG Boundary Scan is enabled when FWUP, NRSTB and JTAGSEL are high while TST is tied low
during power-up and must be kept in this state during the whole boundary scan operation. VDDCORE must be
externally supplied between 1.8V and 1.95V. The SAMPLE, EXTEST and BYPASS functions are implemented. In
SWD/JTAG debug mode, the ARM processor responds with a non-JTAG chip ID that identifies the processor. This
is not IEEE 1149.1 JTAG-compliant.
It is not possible to switch directly between JTAG Boundary Scan and SWJ Debug Port operations. A chip reset
must be performed after JTAGSEL is changed.
A Boundary-scan Descriptor Language (BSDL) file to set up the test is provided on www.atmel.com.
11.5.7.1 JTAG Boundary-scan Register
The Boundary-scan Register (BSR) contains a number of bits which correspond to active pins and associated
control signals.
Each SAM3 input/output pin corresponds to a 3-bit register in the BSR. The OUTPUT bit contains data that can be
forced on the pad. The INPUT bit facilitates the observability of data applied to the pad. The CONTROL bit selects
the direction of the pad.
For more information, please refer to BDSL files available for the SAM3 Series.
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11.5.8 ID Code Register
Access: Read-only
• VERSION[31:28]: Product Version Number
Set to 0x0.
• PART NUMBER[27:12]: Product Part Number
• MANUFACTURER IDENTITY[11:1]
Set to 0x01F.
• Bit[0] Required by IEEE Std. 1149.1.
Set to 0x1.
31 30 29 28 27 26 25 24
VERSION PART NUMBER
23 22 21 20 19 18 17 16
PART NUMBER
15 14 13 12 11 10 9 8
PART NUMBER MANUFACTURER IDENTITY
76543210
MANUFACTURER IDENTITY 1
Chip Name Chip ID
SAM3X 0x05B2B
Chip Name JTAG ID Code
SAM3X 0x05B2B03F
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12. Reset Controller (RSTC)
12.1 Description
The Reset Controller (RSTC), based on power-on reset cells, handles all the resets of the system without any
external components. It reports which reset occurred last.
The Reset Controller also drives independently or simultaneously the external reset and the peripheral and
processor resets.
12.2 Embedded Characteristics
Manages all Resets of the System, Including
̶External Devices through the NRST Pin
̶Processor Reset
̶Peripheral Set Reset
Based on Embedded Power-on Cell
Reset Source Status
̶Status of the Last Reset
̶Either Software Reset, User Reset, Watchdog Reset
External Reset Signal Shaping
AMBA™-compliant Interface
̶Interface to the ARM® Advanced Peripheral Bus
12.3 Block Diagram
Figure 12-1. Reset Controller Block Diagram
NRST
proc_nreset
wd_fault
periph_nreset
SLCK
Reset
State
Manager
Reset Controller
rstc_irq
NRST
Manager
exter_nreset
nrst_out
core_backup_reset
WDRPROC
user_reset
vddcore_nreset
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12.4 Functional Description
12.4.1 Reset Controller Overview
The Reset Controller is made up of an NRST Manager and a Reset State Manager. It runs at Slow Clock and
generates the following reset signals:
proc_nreset: Processor reset line. It also resets the Watchdog Timer.
periph_nreset: Affects the whole set of embedded peripherals.
nrst_out: Drives the NRST pin.
These reset signals are asserted by the Reset Controller, either on external events or on software action. The
Reset State Manager controls the generation of reset signals and provides a signal to the NRST Manager when an
assertion of the NRST pin is required.
The NRST Manager shapes the NRST assertion during a programmable time, thus controlling external device
resets.
The Reset Controller Mode Register (RSTC_MR), allowing the configuration of the Reset Controller, is powered
with VDDIO, so that its configuration is saved as long as VDDIO is on.
12.4.2 NRST Manager
After power-up, NRST is an output during the ERSTL time period defined in the RSTC_MR. When ERSTL has
elapsed, the pin behaves as an input and all the system is held in reset if NRST is tied to GND by an external
signal.
The NRST Manager samples the NRST input pin and drives this pin low when required by the Reset State
Manager. Figure 12-2 shows the block diagram of the NRST Manager.
Figure 12-2. NRST Manager
12.4.2.1 NRST Signal or Interrupt
The NRST Manager samples the NRST pin at Slow Clock speed. When the line is detected low, a User Reset is
reported to the Reset State Manager.
However, the NRST Manager can be programmed to not trigger a reset when an assertion of NRST occurs.
Writing the bit URSTEN at 0 in RSTC_MR disables the User Reset trigger.
The level of the pin NRST can be read at any time in the bit NRSTL (NRST level) in RSTC_SR. As soon as the pin
NRST is asserted, the bit URSTS in RSTC_SR is set. This bit clears only when RSTC_SR is read.
The Reset Controller can also be programmed to generate an interrupt instead of generating a reset. To do so, the
bit URSTIEN in RSTC_MR must be written at 1.
External Reset Timer
URSTS
URSTEN
ERSTL
exter_nreset
URSTIEN
RSTC_MR
RSTC_MR
RSTC_MR
RSTC_SR
NRSTL
nrst_out
NRST
rstc_irq
Other
interrupt
sources
user_reset
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12.4.2.2 NRST External Reset Control
The Reset State Manager asserts the signal ext_nreset to assert the NRST pin. When this occurs, the “nrst_out”
signal is driven low by the NRST Manager for a time programmed by the field ERSTL in RSTC_MR. This assertion
duration, named EXTERNAL_RESET_LENGTH, lasts 2(ERSTL+1) Slow Clock cycles. This gives the approximate
duration of an assertion between 60 µs and 2 seconds. Note that ERSTL at 0 defines a two-cycle duration for the
NRST pulse.
This feature allows the Reset Controller to shape the NRST pin level, and thus to guarantee that the NRST line is
driven low for a time compliant with potential external devices connected on the system reset.
As the ERSTL field is within RSTC_MR register, which is backed-up, it can be used to shape the system power-up
reset for devices requiring a longer startup time than the Slow Clock Oscillator.
12.4.3 Brownout Manager
The Brownout manager is embedded within the Supply Controller, please refer to the product Supply Controller
section for a detailed description.
12.4.4 Reset States
The Reset State Manager handles the different reset sources and generates the internal reset signals. It reports
the reset status in the field RSTTYP of the Status Register (RSTC_SR). The update of the field RSTTYP is
performed when the processor reset is released.
12.4.4.1 General Reset
A general reset occurs when a Power-on-reset is detected, an Asynchronous Master Reset (NRSTB pin) is
requested, a Brownout or a Voltage regulation loss is detected by the Supply controller. The vddcore_nreset signal
is asserted by the Supply Controller when a general reset occurs.
All the reset signals are released and the field RSTTYP in RSTC_SR reports a General Reset. As the RSTC_MR
is reset, the NRST line rises 2 cycles after the vddcore_nreset, as ERSTL defaults at value 0x0.
Figure 12-3 shows how the General Reset affects the reset signals.
Figure 12-3. General Reset State
SLCK
periph_nreset
proc_nreset
NRST
(nrst_out)
EXTERNAL RESET LENGTH
= 2 cycles
MCK
Processor Startup
= 2 cycles
backup_nreset
Any
Freq.
RSTTYP XXX 0x0 = General Reset XXX
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12.4.4.2 Backup Reset
A Backup reset occurs when the chip returns from Backup mode. The core_backup_reset signal is asserted by the
Supply Controller when a Backup reset occurs.
The field RSTTYP in RSTC_SR is updated to report a Backup Reset.
12.4.4.3 User Reset
The User Reset is entered when a low level is detected on the NRST pin and the bit URSTEN in RSTC_MR is at 1.
The NRST input signal is resynchronized with SLCK to insure proper behavior of the system.
The User Reset is entered as soon as a low level is detected on NRST. The Processor Reset and the Peripheral
Reset are asserted.
The User Reset is left when NRST rises, after a two-cycle resynchronization time and a 3-cycle processor startup.
The processor clock is re-enabled as soon as NRST is confirmed high.
When the processor reset signal is released, the RSTTYP field of the Status Register (RSTC_SR) is loaded with
the value 0x4, indicating a User Reset.
The NRST Manager guarantees that the NRST line is asserted for EXTERNAL_RESET_LENGTH Slow Clock
cycles, as programmed in the field ERSTL. However, if NRST does not rise after EXTERNAL_RESET_LENGTH
because it is driven low externally, the internal reset lines remain asserted until NRST actually rises.
Figure 12-4. User Reset State
SLCK
periph_nreset
proc_nreset
NRST
NRST
(nrst_out)
>= EXTERNAL RESET LENGTH
MCK
Processor Startup
= 2 cycles
Any
Freq.
Resynch.
2 cycles
RSTTYP Any XXX
Resynch.
2 cycles
0x4 = User Reset
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12.4.4.4 Software Reset
The Reset Controller offers several commands used to assert the different reset signals. These commands are
performed by writing the Control Register (RSTC_CR) with the following bits at 1:
PROCRST: Writing PROCRST at 1 resets the processor and the watchdog timer.
PERRST: Writing PERRST at 1 resets all the embedded peripherals, including the memory system, and, in
particular, the Remap Command. The Peripheral Reset is generally used for debug purposes.
Except for debug purposes, PERRST must always be used in conjunction with PROCRST (PERRST and
PROCRST set both at 1 simultaneously).
EXTRST: Writing EXTRST at 1 asserts low the NRST pin during a time defined by the field ERSTL in the
Mode Register (RSTC_MR).
The software reset is entered if at least one of these bits is set by the software. All these commands can be
performed independently or simultaneously. The software reset lasts 3 Slow Clock cycles.
The internal reset signals are asserted as soon as the register write is performed. This is detected on the Master
Clock (MCK). They are released when the software reset is left, i.e.; synchronously to SLCK.
If EXTRST is set, the nrst_out signal is asserted depending on the programming of the field ERSTL. However, the
resulting falling edge on NRST does not lead to a User Reset.
If and only if the PROCRST bit is set, the Reset Controller reports the software status in the field RSTTYP of the
Status Register (RSTC_SR). Other Software Resets are not reported in RSTTYP.
As soon as a software operation is detected, the bit SRCMP (Software Reset Command in Progress) is set in the
Status Register (RSTC_SR). It is cleared as soon as the software reset is left. No other software reset can be
performed while the SRCMP bit is set, and writing any value in RSTC_CR has no effect.
Figure 12-5. Software Reset
SLCK
periph_nreset
if PERRST=1
proc_nreset
if PROCRST=1
Write RSTC_CR
NRST
(nrst_out)
if EXTRST=1
EXTERNAL RESET LENGTH
8 cycles (ERSTL=2)
MCK
Processor Startup
= 2 cycles
Any
Freq.
RSTTYP Any XXX 0x3 = Software Reset
Resynch.
1 cycle
SRCMP in RSTC_SR
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12.4.4.5 Watchdog Reset
The Watchdog Reset is entered when a watchdog fault occurs. This state lasts 3 Slow Clock cycles.
When in Watchdog Reset, assertion of the reset signals depends on the WDRPROC bit in WDT_MR:
If WDRPROC is 0, the Processor Reset and the Peripheral Reset are asserted. The NRST line is also
asserted, depending on the programming of the field ERSTL. However, the resulting low level on NRST
does not result in a User Reset state.
If WDRPROC = 1, only the processor reset is asserted.
The Watchdog Timer is reset by the proc_nreset signal. As the watchdog fault always causes a processor reset if
WDRSTEN is set, the Watchdog Timer is always reset after a Watchdog Reset, and the Watchdog is enabled by
default and with a period set to a maximum.
When the WDRSTEN in WDT_MR bit is reset, the watchdog fault has no impact on the reset controller.
Figure 12-6. Watchdog Reset
Only if
WDRPROC = 0
SLCK
periph_nreset
proc_nreset
wd_fault
NRST
(nrst_out)
EXTERNAL RESET LENGTH
8 cycles (ERSTL=2)
MCK
Processor Startup
= 2 cycles
Any
Freq.
RSTTYP Any XXX 0x2 = Watchdog Reset
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12.4.5 Reset State Priorities
The Reset State Manager manages the following priorities between the different reset sources, given in
descending order:
General Reset
Backup Reset
Watchdog Reset
Software Reset
User Reset
Particular cases are listed below:
When in User Reset:
̶A watchdog event is impossible because the Watchdog Timer is being reset by the proc_nreset signal.
̶A software reset is impossible, since the processor reset is being activated.
When in Software Reset:
̶A watchdog event has priority over the current state.
̶The NRST has no effect.
When in Watchdog Reset:
̶The processor reset is active and so a Software Reset cannot be programmed.
̶A User Reset cannot be entered.
12.4.6 Reset Controller Status Register
The Reset Controller status register (RSTC_SR) provides several status fields:
RSTTYP field: This field gives the type of the last reset, as explained in previous sections.
SRCMP bit: This field indicates that a Software Reset Command is in progress and that no further software
reset should be performed until the end of the current one. This bit is automatically cleared at the end of the
current software reset.
NRSTL bit: The NRSTL bit of the Status Register gives the level of the NRST pin sampled on each MCK
rising edge.
URSTS bit: A high-to-low transition of the NRST pin sets the URSTS bit of the RSTC_SR register. This
transition is also detected on the Master Clock (MCK) rising edge (see Figure 12-7). If the User Reset is
disabled (URSTEN = 0) and if the interruption is enabled by the URSTIEN bit in the RSTC_MR register, the
URSTS bit triggers an interrupt. Reading the RSTC_SR status register resets the URSTS bit and clears the
interrupt.
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Figure 12-7. Reset Controller Status and Interrupt
MCK
NRST
NRSTL
2 cycle
resynchronization 2 cycle
resynchronization
URSTS
read
RSTC_SR
Peripheral Access
rstc_irq
if (URSTEN = 0) and
(URSTIEN = 1)
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12.5 Reset Controller (RSTC) User Interface
Table 12-1. Register Mapping
Offset Register Name Access Reset
0x00 Control Register RSTC_CR Write-only -
0x04 Status Register RSTC_SR Read-only 0x0000_0000
0x08 Mode Register RSTC_MR Read-write 0x0000 0001
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12.5.1 Reset Controller Control Register
Name: RSTC_CR
Address: 0x400E1A00
Access: Write-only
• PROCRST: Processor Reset
0: No effect.
1: If KEY is correct, resets the processor.
• PERRST: Peripheral Reset
0: No effect.
1: If KEY is correct, resets the peripherals.
• EXTRST: External Reset
0: No effect.
1: If KEY is correct, asserts the NRST pin.
• KEY: Password
Should be written at value 0xA5. Writing any other value in this field aborts the write operation.
31 30 29 28 27 26 25 24
KEY
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––– –
76543210
––––EXTRSTPERRST–PROCRST
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12.5.2 Reset Controller Status Register
Name: RSTC_SR
Address: 0x400E1A04
Access: Read-only
• URSTS: User Reset Status
0: No high-to-low edge on NRST happened since the last read of RSTC_SR.
1: At least one high-to-low transition of NRST has been detected since the last read of RSTC_SR.
• RSTTYP: Reset Type
Reports the cause of the last processor reset. Reading this RSTC_SR does not reset this field.
• NRSTL: NRST Pin Level
Registers the NRST Pin Level at Master Clock (MCK).
• SRCMP: Software Reset Command in Progress
0: No software command is being performed by the reset controller. The reset controller is ready for a software command.
1: A software reset command is being performed by the reset controller. The reset controller is busy.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––SRCMPNRSTL
15 14 13 12 11 10 9 8
––––– RSTTYP
76543210
–––––––URSTS
RSTTYP Reset Type Comments
0 0 0 General Reset First power-up Reset
0 0 1 Backup Reset Return from Backup mode
0 1 0 Watchdog Reset Watchdog fault occurred
0 1 1 Software Reset Processor reset required by the software
1 0 0 User Reset NRST pin detected low
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12.5.3 Reset Controller Mode Register
Name: RSTC_MR
Address: 0x400E1A08
Access: Read-write
• URSTEN: User Reset Enable
0: The detection of a low level on the pin NRST does not generate a User Reset.
1: The detection of a low level on the pin NRST triggers a User Reset.
• URSTIEN: User Reset Interrupt Enable
0: USRTS bit in RSTC_SR at 1 has no effect on rstc_irq.
1: USRTS bit in RSTC_SR at 1 asserts rstc_irq if URSTEN = 0.
• ERSTL: External Reset Length
This field defines the external reset length. The external reset is asserted during a time of 2(ERSTL+1) Slow Clock cycles.
This allows assertion duration to be programmed between 60 µs and 2 seconds.
• KEY: Password
Should be written at value 0xA5. Writing any other value in this field aborts the write operation.
31 30 29 28 27 26 25 24
KEY
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––– ERSTL
76543210
– – URSTIEN – – – URSTEN
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13. Real-time Timer (RTT)
13.1 Description
The Real-time Timer is built around a 32-bit counter used to count roll-over events of the programmable 16-bit
prescaler which enables counting elapsed seconds from a 32 kHz slow clock source. It generates a periodic
interrupt and/or triggers an alarm on a programmed value.
13.2 Embedded Characteristics
32-bit Free-running Counter on prescaled slow clock
16-bit Configurable Prescaler
Interrupt on Alarm
13.3 Block Diagram
Figure 13-1. Real-time Timer
SLCK
RTPRES
RTTINC
ALMS
16-bit
Divider
32-bit
Counter
ALMV
=
CRTV
RTT_MR
RTT_VR
RTT_AR
RTT_SR
RTTINCIEN
RTT_MR
0
10
ALMIEN
rtt_int
RTT_MR
set
set
RTT_SR
read
RTT_SR
reset
reset
RTT_MR
reload
rtt_alarm
RTTRST
RTT_MR
RTTRST
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13.4 Functional Description
The Real-time Timer can be used to count elapsed seconds. It is built around a 32-bit counter fed by Slow Clock
divided by a programmable 16-bit value. The value can be programmed in the field RTPRES of the Real-time
Mode Register (RTT_MR).
Programming RTPRES at 0x00008000 corresponds to feeding the real-time counter with a 1 Hz signal (if the Slow
Clock is 32.768 kHz). The 32-bit counter can count up to 232 seconds, corresponding to more than 136 years, then
roll over to 0.
The Real-time Timer can also be used as a free-running timer with a lower time-base. The best accuracy is
achieved by writing RTPRES to 3. Programming RTPRES to 1 or 2 is possible, but may result in losing status
events because the status register is cleared two Slow Clock cycles after read. Thus if the RTT is configured to
trigger an interrupt, the interrupt occurs during 2 Slow Clock cycles after reading RTT_SR. To prevent several
executions of the interrupt handler, the interrupt must be disabled in the interrupt handler and re-enabled when the
status register is clear.
The Real-time Timer value (CRTV) can be read at any time in the register RTT_VR (Real-time Value Register). As
this value can be updated asynchronously from the Master Clock, it is advisable to read this register twice at the
same value to improve accuracy of the returned value.
The current value of the counter is compared with the value written in the alarm register RTT_AR (Real-time Alarm
Register). If the counter value matches the alarm, the bit ALMS in RTT_SR is set. The alarm register is set to its
maximum value, corresponding to 0xFFFF_FFFF, after a reset.
The bit RTTINC in RTT_SR is set each time the Real-time Timer counter is incremented. This bit can be used to
start a periodic interrupt, the period being one second when the RTPRES is programmed with 0x8000 and Slow
Clock equal to 32.768 Hz.
Reading the RTT_SR status register resets the RTTINC and ALMS fields.
Writing the bit RTTRST in RTT_MR immediately reloads and restarts the clock divider with the new programmed
value. This also resets the 32-bit counter.
Note: Because of the asynchronism between the Slow Clock (SCLK) and the System Clock (MCK):
1) The restart of the counter and the reset of the RTT_VR current value register is effective only 2 slow clock cycles
after the write of the RTTRST bit in the RTT_MR register.
2) The status register flags reset is taken into account only 2 slow clock cycles after the read of the RTT_SR (Status
Register).
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Figure 13-2. RTT Counting
Prescaler
ALMVALMV-10 ALMV+1
0
RTPRES - 1
RTT
APB cycle
read RTT_SR
ALMS (RTT_SR)
APB Interface
SCLK
RTTINC (RTT_SR)
ALMV+2 ALMV+3
...
APB cycle
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13.5 Real-time Timer (RTT) User Interface
Table 13-1. Register Mapping
Offset Register Name Access Reset
0x00 Mode Register RTT_MR Read-write 0x0000_8000
0x04 Alarm Register RTT_AR Read-write 0xFFFF_FFFF
0x08 Value Register RTT_VR Read-only 0x0000_0000
0x0C Status Register RTT_SR Read-only 0x0000_0000
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13.5.1 Real-time Timer Mode Register
Name: RTT_MR
Address: 0x400E1A30
Access: Read-write
• RTPRES: Real-time Timer Prescaler Value
Defines the number of SLCK periods required to increment the Real-time timer. RTPRES is defined as follows:
RTPRES = 0: The prescaler period is equal to 216 * SCLK period.
RTPRES ≠ 0: The prescaler period is equal to RTPRES * SCLK period.
• ALMIEN: Alarm Interrupt Enable
0 = The bit ALMS in RTT_SR has no effect on interrupt.
1 = The bit ALMS in RTT_SR asserts interrupt.
• RTTINCIEN: Real-time Timer Increment Interrupt Enable
0 = The bit RTTINC in RTT_SR has no effect on interrupt.
1 = The bit RTTINC in RTT_SR asserts interrupt.
• RTTRST: Real-time Timer Restart
0 = No effect.
1 = Reloads and restarts the clock divider with the new programmed value. This also resets the 32-bit counter.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––RTTRSTRTTINCIENALMIEN
15 14 13 12 11 10 9 8
RTPRES
76543210
RTPRES
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13.5.2 Real-time Timer Alarm Register
Name: RTT_AR
Address: 0x400E1A34
Access: Read-write
• ALMV: Alarm Value
Defines the alarm value (ALMV+1) compared with the Real-time Timer.
31 30 29 28 27 26 25 24
ALMV
23 22 21 20 19 18 17 16
ALMV
15 14 13 12 11 10 9 8
ALMV
76543210
ALMV
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13.5.3 Real-time Timer Value Register
Name: RTT_VR
Address: 0x400E1A38
Access: Read-only
• CRTV: Current Real-time Value
Returns the current value of the Real-time Timer.
31 30 29 28 27 26 25 24
CRTV
23 22 21 20 19 18 17 16
CRTV
15 14 13 12 11 10 9 8
CRTV
76543210
CRTV
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13.5.4 Real-time Timer Status Register
Name: RTT_SR
Address: 0x400E1A3C
Access: Read-only
• ALMS: Real-time Alarm Status
0 = The Real-time Alarm has not occurred since the last read of RTT_SR.
1 = The Real-time Alarm occurred since the last read of RTT_SR.
• RTTINC: Real-time Timer Increment
0 = The Real-time Timer has not been incremented since the last read of the RTT_SR.
1 = The Real-time Timer has been incremented since the last read of the RTT_SR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––RTTINCALMS
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14. Real-time Clock (RTC)
14.1 Description
The Real-time Clock (RTC) peripheral is designed for very low power consumption.
It combines a complete time-of-day clock with alarm and a two-hundred-year Gregorian calendar, complemented
by a programmable periodic interrupt. The alarm and calendar registers are accessed by a 32-bit data bus.
The time and calendar values are coded in binary-coded decimal (BCD) format. The time format can be 24-hour
mode or 12-hour mode with an AM/PM indicator.
Updating time and calendar fields and configuring the alarm fields are performed by a parallel capture on the 32-bit
data bus. An entry control is performed to avoid loading registers with incompatible BCD format data or with an
incompatible date according to the current month/year/century.
14.2 Embedded Characteristics
Low Power Consumption
Full Asynchronous Design
Two Hundred Year Gregorian Calendar
Programmable Periodic Interrupt
Time, Date and Alarm 32-bit Parallel Load
Write Protected Registers
14.3 Block Diagram
Figure 14-1. RTC Block Diagram
14.4 Product Dependencies
14.4.1 Power Management
The Real-time Clock is continuously clocked at 32768 Hz. The Power Management Controller has no effect on
RTC behavior.
14.4.2 Interrupt
RTC interrupt line is connected on one of the internal sources of the interrupt controller. RTC interrupt requires the
interrupt controller to be programmed first.
Bus Interface
32768 Divider TimeSlow Clock: SLCK
Bus Interface
Date
RTC Interrupt
Entry
Control Interrupt
Control
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14.5 Functional Description
The RTC provides a full binary-coded decimal (BCD) clock that includes century (19/20), year (with leap years),
month, date, day, hours, minutes and seconds.
The valid year range is 1900 to 2099 in Gregorian mode, a two-hundred-year calendar.
The RTC can operate in 24-hour mode or in 12-hour mode with an AM/PM indicator.
Corrections for leap years are included (all years divisible by 4 being leap years). This is correct up to the year
2099.
14.5.1 Reference Clock
The reference clock is Slow Clock (SLCK). It can be driven internally or by an external 32.768 kHz crystal.
During low power modes of the processor, the oscillator runs and power consumption is critical. The crystal
selection has to take into account the current consumption for power saving and the frequency drift due to
temperature effect on the circuit for time accuracy.
14.5.2 Timing
The RTC is updated in real time at one-second intervals in normal mode for the counters of seconds, at one-
minute intervals for the counter of minutes and so on.
Due to the asynchronous operation of the RTC with respect to the rest of the chip, to be certain that the value read
in the RTC registers (century, year, month, date, day, hours, minutes, seconds) are valid and stable, it is
necessary to read these registers twice. If the data is the same both times, then it is valid. Therefore, a minimum of
two and a maximum of three accesses are required.
14.5.3 Alarm
The RTC has five programmable fields: month, date, hours, minutes and seconds.
Each of these fields can be enabled or disabled to match the alarm condition:
If all the fields are enabled, an alarm flag is generated (the corresponding flag is asserted and an interrupt
generated if enabled) at a given month, date, hour/minute/second.
If only the “seconds” field is enabled, then an alarm is generated every minute.
Depending on the combination of fields enabled, a large number of possibilities are available to the user ranging
from minutes to 365/366 days.
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14.5.4 Error Checking
Verification on user interface data is performed when accessing the century, year, month, date, day, hours,
minutes, seconds and alarms. A check is performed on illegal BCD entries such as illegal date of the month with
regard to the year and century configured.
If one of the time fields is not correct, the data is not loaded into the register/counter and a flag is set in the validity
register. The user can not reset this flag. It is reset as soon as an acceptable value is programmed. This avoids
any further side effects in the hardware. The same procedure is done for the alarm.
The following checks are performed:
1. Century (check if it is in range 19 - 20)
2. Year (BCD entry check)
3. Date (check range 01 - 31)
4. Month (check if it is in BCD range 01 - 12, check validity regarding “date”)
5. Day (check range 1 - 7)
6. Hour (BCD checks: in 24-hour mode, check range 00 - 23 and check that AM/PM flag is not set if RTC is set
in 24-hour mode; in 12-hour mode check range 01 - 12)
7. Minute (check BCD and range 00 - 59)
8. Second (check BCD and range 00 - 59)
Note: If the 12-hour mode is selected by means of the RTC_MODE register, a 12-hour value can be programmed and the
returned value on RTC_TIME will be the corresponding 24-hour value. The entry control checks the value of the
AM/PM indicator (bit 22 of RTC_TIME register) to determine the range to be checked.
14.5.5 Updating Time/Calendar
To update any of the time/calendar fields, the user must first stop the RTC by setting the corresponding field in the
Control Register. Bit UPDTIM must be set to update time fields (hour, minute, second) and bit UPDCAL must be
set to update calendar fields (century, year, month, date, day).
Then the user must poll or wait for the interrupt (if enabled) of bit ACKUPD in the Status Register. Once the bit
reads 1, it is mandatory to clear this flag by writing the corresponding bit in RTC_SCCR. The user can now write to
the appropriate Time and Calendar register.
Once the update is finished, the user must reset (0) UPDTIM and/or UPDCAL in the Control
When entering programming mode of the calendar fields, the time fields remain enabled. When entering the
programming mode of the time fields, both time and calendar fields are stopped. This is due to the location of the
calendar logic circuity (downstream for low-power considerations). It is highly recommended to prepare all the
fields to be updated before entering programming mode. In successive update operations, the user must wait at
least one second after resetting the UPDTIM/UPDCAL bit in the RTC_CR (Control Register) before setting these
bits again. This is done by waiting for the SEC flag in the Status Register before setting UPDTIM/UPDCAL bit.
After resetting UPDTIM/UPDCAL, the SEC flag must also be cleared.
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Figure 14-2. Update Sequence
Prepare TIme or Calendar Fields
Set UPDTIM and/or UPDCAL
bit(s) in RTC_CR
Read RTC_SR
ACKUPD
= 1 ?
Clear ACKUPD bit in RTC_SCCR
Update Time and/or Calendar values in
RTC_TIMR/RTC_CALR
Clear UPDTIM and/or UPDCAL bit in
RTC_CR
No
Yes
Begin
End
Polling or
IRQ (if enabled)
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14.6 Real-time Clock (RTC) User Interface
Note: if an offset is not listed in the table it must be considered as reserved.
Table 14-1. Register Mapping
Offset Register Name Access Reset
0x00 Control Register RTC_CR Read-write 0x0
0x04 Mode Register RTC_MR Read-write 0x0
0x08 Time Register RTC_TIMR Read-write 0x0
0x0C Calendar Register RTC_CALR Read-write 0x01210720
0x10 Time Alarm Register RTC_TIMALR Read-write 0x0
0x14 Calendar Alarm Register RTC_CALALR Read-write 0x01010000
0x18 Status Register RTC_SR Read-only 0x0
0x1C Status Clear Command Register RTC_SCCR Write-only –
0x20 Interrupt Enable Register RTC_IER Write-only –
0x24 Interrupt Disable Register RTC_IDR Write-only –
0x28 Interrupt Mask Register RTC_IMR Read-only 0x0
0x2C Valid Entry Register RTC_VER Read-only 0x0
0x30–0xE0 Reserved Register – – –
0xE4 Write Protect Mode Register RTC_WPMR Read-write 0x00000000
0xE8–0xF8 Reserved Register – – –
0xFC Reserved Register – – –
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14.6.1 RTC Control Register
Name: RTC_CR
Address: 0x400E1A60
Access: Read-write
This register can only be written if the WPEN bit is cleared in “RTC Write Protect Mode Register” on page 259.
• UPDTIM: Update Request Time Register
0: No effect.
1: Stops the RTC time counting.
Time counting consists of second, minute and hour counters. Time counters can be programmed once this bit is set and
acknowledged by the bit ACKUPD of the Status Register.
• UPDCAL: Update Request Calendar Register
0: No effect.
1: Stops the RTC calendar counting.
Calendar counting consists of day, date, month, year and century counters. Calendar counters can be programmed once
this bit is set.
• TIMEVSEL: Time Event Selection
The event that generates the flag TIMEV in RTC_SR (Status Register) depends on the value of TIMEVSEL.
• CALEVSEL: Calendar Event Selection
The event that generates the flag CALEV in RTC_SR depends on the value of CALEVSEL
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––– CALEVSEL
15 14 13 12 11 10 9 8
–––––– TIMEVSEL
76543210
––––––UPDCALUPDTIM
Value Name Description
0 MINUTE Minute change
1 HOUR Hour change
2 MIDNIGHT Every day at midnight
3 NOON Every day at noon
Value Name Description
0 WEEK Week change (every Monday at time 00:00:00)
1 MONTH Month change (every 01 of each month at time 00:00:00)
2 YEAR Year change (every January 1 at time 00:00:00)
3–
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14.6.2 RTC Mode Register
Name: RTC_MR
Address: 0x400E1A64
Access: Read-write
• HRMOD: 12-/24-hour Mode
0: 24-hour mode is selected.
1: 12-hour mode is selected.
All non-significant bits read zero.
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––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–––––––HRMOD
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14.6.3 RTC Time Register
Name: RTC_TIMR
Address: 0x400E1A68
Access: Read-write
• SEC: Current Second
The range that can be set is 0 - 59 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
• MIN: Current Minute
The range that can be set is 0 - 59 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
• HOUR: Current Hour
The range that can be set is 1 - 12 (BCD) in 12-hour mode or 0 - 23 (BCD) in 24-hour mode.
• AMPM: Ante Meridiem Post Meridiem Indicator
This bit is the AM/PM indicator in 12-hour mode.
0: AM.
1: PM.
All non-significant bits read zero.
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––––––––
2322 21 20 19 1817 16
–AMPM HOUR
15 14 1312 11 10 9 8
–MIN
76543210
–SEC
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14.6.4 RTC Calendar Register
Name: RTC_CALR
Address: 0x400E1A6C
Access: Read-write
• CENT: Current Century
The range that can be set is 19 - 20 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
• YEAR: Current Year
The range that can be set is 00 - 99 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
• MONTH: Current Month
The range that can be set is 01 - 12 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
• DAY: Current Day in Current Week
The range that can be set is 1 - 7 (BCD).
The coding of the number (which number represents which day) is user-defined as it has no effect on the date counter.
• DATE: Current Day in Current Month
The range that can be set is 01 - 31 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
All non-significant bits read zero.
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–– DATE
2322 21 20 19 1817 16
DAY MONTH
15 14 1312 11 10 9 8
YEAR
76543210
–CENT
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14.6.5 RTC Time Alarm Register
Name: RTC_TIMALR
Address: 0x400E1A70
Access: Read-write
This register can only be written if the WPEN bit is cleared in “RTC Write Protect Mode Register” on page 259.
• SEC: Second Alarm
This field is the alarm field corresponding to the BCD-coded second counter.
• SECEN: Second Alarm Enable
0: The second-matching alarm is disabled.
1: The second-matching alarm is enabled.
• MIN: Minute Alarm
This field is the alarm field corresponding to the BCD-coded minute counter.
• MINEN: Minute Alarm Enable
0: The minute-matching alarm is disabled.
1: The minute-matching alarm is enabled.
• HOUR: Hour Alarm
This field is the alarm field corresponding to the BCD-coded hour counter.
• AMPM: AM/PM Indicator
This field is the alarm field corresponding to the BCD-coded hour counter.
• HOUREN: Hour Alarm Enable
0: The hour-matching alarm is disabled.
1: The hour-matching alarm is enabled.
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––––––––
2322 21 20 19 1817 16
HOUREN AMPM HOUR
15 14 1312 11 10 9 8
MINEN MIN
76543210
SECEN SEC
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14.6.6 RTC Calendar Alarm Register
Name: RTC_CALALR
Address: 0x400E1A74
Access: Read-write
This register can only be written if the WPEN bit is cleared in “RTC Write Protect Mode Register” on page 259.
• MONTH: Month Alarm
This field is the alarm field corresponding to the BCD-coded month counter.
• MTHEN: Month Alarm Enable
0: The month-matching alarm is disabled.
1: The month-matching alarm is enabled.
•DATE: Date Alarm
This field is the alarm field corresponding to the BCD-coded date counter.
• DATEEN: Date Alarm Enable
0: The date-matching alarm is disabled.
1: The date-matching alarm is enabled.
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DATEEN – DATE
2322 21 20 19 1817 16
MTHEN – – MONTH
15 14 1312 11 10 9 8
––––––––
76543210
––––––––
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14.6.7 RTC Status Register
Name: RTC_SR
Address: 0x400E1A78
Access: Read-only
• ACKUPD: Acknowledge for Update
0: Time and calendar registers cannot be updated.
1: Time and calendar registers can be updated.
• ALARM: Alarm Flag
0: No alarm matching condition occurred.
1: An alarm matching condition has occurred.
• SEC: Second Event
0: No second event has occurred since the last clear.
1: At least one second event has occurred since the last clear.
• TIMEV: Time Event
0: No time event has occurred since the last clear.
1: At least one time event has occurred since the last clear.
The time event is selected in the TIMEVSEL field in RTC_CR (Control Register) and can be any one of the following
events: minute change, hour change, noon, midnight (day change).
• CALEV: Calendar Event
0: No calendar event has occurred since the last clear.
1: At least one calendar event has occurred since the last clear.
The calendar event is selected in the CALEVSEL field in RTC_CR and can be any one of the following events: week
change, month change and year change.
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––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–––CALEVTIMEVSEC ALARM ACKUPD
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14.6.8 RTC Status Clear Command Register
Name: RTC_SCCR
Address: 0x400E1A7C
Access: Write-only
• ACKCLR: Acknowledge Clear
0: No effect.
1: Clears corresponding status flag in the Status Register (RTC_SR).
• ALRCLR: Alarm Clear
0: No effect.
1: Clears corresponding status flag in the Status Register (RTC_SR).
• SECCLR: Second Clear
0: No effect.
1: Clears corresponding status flag in the Status Register (RTC_SR).
• TIMCLR: Time Clear
0: No effect.
1: Clears corresponding status flag in the Status Register (RTC_SR).
• CALCLR: Calendar Clear
0: No effect.
1: Clears corresponding status flag in the Status Register (RTC_SR).
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––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
– – – CALCLR TIMCLR SECCLR ALRCLR ACKCLR
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14.6.9 RTC Interrupt Enable Register
Name: RTC_IER
Address: 0x400E1A80
Access: Write-only
• ACKEN: Acknowledge Update Interrupt Enable
0: No effect.
1: The acknowledge for update interrupt is enabled.
• ALREN: Alarm Interrupt Enable
0: No effect.
1: The alarm interrupt is enabled.
• SECEN: Second Event Interrupt Enable
0: No effect.
1: The second periodic interrupt is enabled.
• TIMEN: Time Event Interrupt Enable
0: No effect.
1: The selected time event interrupt is enabled.
• CALEN: Calendar Event Interrupt Enable
0: No effect.
1: The selected calendar event interrupt is enabled.
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––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–––CALENTIMENSECEN ALREN ACKEN
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14.6.10 RTC Interrupt Disable Register
Name: RTC_IDR
Address: 0x400E1A84
Access: Write-only
• ACKDIS: Acknowledge Update Interrupt Disable
0: No effect.
1: The acknowledge for update interrupt is disabled.
• ALRDIS: Alarm Interrupt Disable
0: No effect.
1: The alarm interrupt is disabled.
• SECDIS: Second Event Interrupt Disable
0: No effect.
1: The second periodic interrupt is disabled.
• TIMDIS: Time Event Interrupt Disable
0: No effect.
1: The selected time event interrupt is disabled.
• CALDIS: Calendar Event Interrupt Disable
0: No effect.
1: The selected calendar event interrupt is disabled.
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––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–––CALDISTIMDISSECDISALRDISACKDIS
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14.6.11 RTC Interrupt Mask Register
Name: RTC_IMR
Address: 0x400E1A88
Access: Read-only
• ACK: Acknowledge Update Interrupt Mask
0: The acknowledge for update interrupt is disabled.
1: The acknowledge for update interrupt is enabled.
• ALR: Alarm Interrupt Mask
0: The alarm interrupt is disabled.
1: The alarm interrupt is enabled.
• SEC: Second Event Interrupt Mask
0: The second periodic interrupt is disabled.
1: The second periodic interrupt is enabled.
• TIM: Time Event Interrupt Mask
0: The selected time event interrupt is disabled.
1: The selected time event interrupt is enabled.
• CAL: Calendar Event Interrupt Mask
0: The selected calendar event interrupt is disabled.
1: The selected calendar event interrupt is enabled.
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––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–––CALTIMSEC ALR ACK
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14.6.12 RTC Valid Entry Register
Name: RTC_VER
Address: 0x400E1A8C
Access: Read-only
• NVTIM: Non-valid Time
0: No invalid data has been detected in RTC_TIMR (Time Register).
1: RTC_TIMR has contained invalid data since it was last programmed.
• NVCAL: Non-valid Calendar
0: No invalid data has been detected in RTC_CALR (Calendar Register).
1: RTC_CALR has contained invalid data since it was last programmed.
• NVTIMALR: Non-valid Time Alarm
0: No invalid data has been detected in RTC_TIMALR (Time Alarm Register).
1: RTC_TIMALR has contained invalid data since it was last programmed.
• NVCALALR: Non-valid Calendar Alarm
0: No invalid data has been detected in RTC_CALALR (Calendar Alarm Register).
1: RTC_CALALR has contained invalid data since it was last programmed.
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––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
––––NVCALALRNVTIMALRNVCALNVTIM
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14.6.13 RTC Write Protect Mode Register
Name: RTC_WPMR
Address: 0x400E1B44
Access: Read-write
• WPEN: Write Protect Enable
0: Disables the Write Protect if WPKEY corresponds to 0x525443 (“RTC” in ASCII).
1: Enables the Write Protect if WPKEY corresponds to 0x525443 (“RTC” in ASCII).
Protects the registers:
“RTC Mode Register” on page 248
“RTC Time Alarm Register” on page 251
“RTC Calendar Alarm Register” on page 252
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
———————WPEN
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15. Watchdog Timer (WDT)
15.1 Description
The Watchdog Timer can be used to prevent system lock-up if the software becomes trapped in a deadlock. It
features a 12-bit down counter that allows a watchdog period of up to 16 seconds (slow clock at 32.768 kHz). It
can generate a general reset or a processor reset only. In addition, it can be stopped while the processor is in
debug mode or idle mode.
15.2 Embedded Characteristics
12-bit Key-protected Programmable Counter
Provides Reset or Interrupt Signals to the System
Counter May Be Stopped While the Processor is in Debug State or in Idle Mode
AMBA™-compliant Interface
̶Interfaces to the ARM® Advanced Peripheral Bus
15.3 Block Diagram
Figure 15-1. Watchdog Timer Block Diagram
=0
10
set
reset
read WDT_SR
or
reset
wdt_fault
(to Reset Controller)
set
reset
WDFIEN
wdt_int
WDT_MR
SLCK
1/128
12-bit Down
Counter
Current
Value
WDD
WDT_MR
<= WDD
WDV
WDRSTT
WDT_MR
WDT_CR
reload
WDUNF
WDERR
reload
write WDT_MR
WDT_MR
WDRSTEN
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15.4 Functional Description
The Watchdog Timer can be used to prevent system lock-up if the software becomes trapped in a deadlock. It is
supplied with VDDCORE. It restarts with initial values on processor reset.
The Watchdog is built around a 12-bit down counter, which is loaded with the value defined in the field WDV of the
Mode Register (WDT_MR). The Watchdog Timer uses the Slow Clock divided by 128 to establish the maximum
Watchdog period to be 16 seconds (with a typical Slow Clock of 32.768 kHz).
After a Processor Reset, the value of WDV is 0xFFF, corresponding to the maximum value of the counter with the
external reset generation enabled (field WDRSTEN at 1 after a Backup Reset). This means that a default
Watchdog is running at reset, i.e., at power-up. The user must either disable it (by setting the WDDIS bit in
WDT_MR) if he does not expect to use it or must reprogram it to meet the maximum Watchdog period the
application requires.
The Watchdog Mode Register (WDT_MR) can be written only once. Only a processor reset resets it. Writing the
WDT_MR register reloads the timer with the newly programmed mode parameters.
In normal operation, the user reloads the Watchdog at regular intervals before the timer underflow occurs, by
writing the Control Register (WDT_CR) with the bit WDRSTT to 1. The Watchdog counter is then immediately
reloaded from WDT_MR and restarted, and the Slow Clock 128 divider is reset and restarted. The WDT_CR
register is write-protected. As a result, writing WDT_CR without the correct hard-coded key has no effect. If an
underflow does occur, the “wdt_fault” signal to the Reset Controller is asserted if the bit WDRSTEN is set in the
Mode Register (WDT_MR). Moreover, the bit WDUNF is set in the Watchdog Status Register (WDT_SR).
To prevent a software deadlock that continuously triggers the Watchdog, the reload of the Watchdog must occur
while the Watchdog counter is within a window between 0 and WDD, WDD is defined in the WatchDog Mode
Register WDT_MR.
Any attempt to restart the Watchdog while the Watchdog counter is between WDV and WDD results in a
Watchdog error, even if the Watchdog is disabled. The bit WDERR is updated in the WDT_SR and the “wdt_fault”
signal to the Reset Controller is asserted.
Note that this feature can be disabled by programming a WDD value greater than or equal to the WDV value. In
such a configuration, restarting the Watchdog Timer is permitted in the whole range [0; WDV] and does not
generate an error. This is the default configuration on reset (the WDD and WDV values are equal).
The status bits WDUNF (Watchdog Underflow) and WDERR (Watchdog Error) trigger an interrupt, provided the bit
WDFIEN is set in the mode register. The signal “wdt_fault” to the reset controller causes a Watchdog reset if the
WDRSTEN bit is set as already explained in the reset controller programmer datasheet. In that case, the
processor and the Watchdog Timer are reset, and the WDERR and WDUNF flags are reset.
If a reset is generated or if WDT_SR is read, the status bits are reset, the interrupt is cleared, and the “wdt_fault”
signal to the reset controller is deasserted.
Writing the WDT_MR reloads and restarts the down counter.
While the processor is in debug state or in idle mode, the counter may be stopped depending on the value
programmed for the bits WDIDLEHLT and WDDBGHLT in the WDT_MR.
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Figure 15-2. Watchdog Behavior
0
WDV
WDD
WDT_CR = WDRSTT
Watchdog
Fault
Normal behavior
Watchdog Error Watchdog Underflow
FFF if WDRSTEN is 1
if WDRSTEN is 0
Forbidden
Window
Permitted
Window
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15.5 Watchdog Timer (WDT) User Interface
Table 15-1. Register Mapping
Offset Register Name Access Reset
0x00 Control Register WDT_CR Write-only -
0x04 Mode Register WDT_MR Read-write Once 0x3FFF_2FFF
0x08 Status Register WDT_SR Read-only 0x0000_0000
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15.5.1 Watchdog Timer Control Register
Name: WDT_CR
Address: 0x400E1A50
Access: Write-only
• WDRSTT: Watchdog Restart
0: No effect.
1: Restarts the Watchdog.
• KEY: Password
Should be written at value 0xA5. Writing any other value in this field aborts the write operation.
3130292827 26 25 24
KEY
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–––––––WDRSTT
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15.5.2 Watchdog Timer Mode Register
Name: WDT_MR
Address: 0x400E1A54
Access: Read-write Once
• WDV: Watchdog Counter Value
Defines the value loaded in the 12-bit Watchdog Counter.
• WDFIEN: Watchdog Fault Interrupt Enable
0: A Watchdog fault (underflow or error) has no effect on interrupt.
1: A Watchdog fault (underflow or error) asserts interrupt.
• WDRSTEN: Watchdog Reset Enable
0: A Watchdog fault (underflow or error) has no effect on the resets.
1: A Watchdog fault (underflow or error) triggers a Watchdog reset.
• WDRPROC: Watchdog Reset Processor
0: If WDRSTEN is 1, a Watchdog fault (underflow or error) activates all resets.
1: If WDRSTEN is 1, a Watchdog fault (underflow or error) activates the processor reset.
• WDD: Watchdog Delta Value
Defines the permitted range for reloading the Watchdog Timer.
If the Watchdog Timer value is less than or equal to WDD, writing WDT_CR with WDRSTT = 1 restarts the timer.
If the Watchdog Timer value is greater than WDD, writing WDT_CR with WDRSTT = 1 causes a Watchdog error.
• WDDBGHLT: Watchdog Debug Halt
0: The Watchdog runs when the processor is in debug state.
1: The Watchdog stops when the processor is in debug state.
• WDIDLEHLT: Watchdog Idle Halt
0: The Watchdog runs when the system is in idle mode.
1: The Watchdog stops when the system is in idle state.
3130292827 26 25 24
WDIDLEHLT WDDBGHLT WDD
2322 21 20 19 1817 16
WDD
15 14 1312 11 10 9 8
WDDISWDRPROC WDRSTEN WDFIEN WDV
76543210
WDV
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• WDDIS: Watchdog Disable
0: Enables the Watchdog Timer.
1: Disables the Watchdog Timer.
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15.5.3 Watchdog Timer Status Register
Name: WDT_SR
Address: 0x400E1A58
Access: Read-only
• WDUNF: Watchdog Underflow
0: No Watchdog underflow occurred since the last read of WDT_SR.
1: At least one Watchdog underflow occurred since the last read of WDT_SR.
• WDERR: Watchdog Error
0: No Watchdog error occurred since the last read of WDT_SR.
1: At least one Watchdog error occurred since the last read of WDT_SR.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
––––––WDERRWDUNF
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16. Supply Controller (SUPC)
16.1 Description
The Supply Controller (SUPC) controls the supply voltage of the Core of the system and manages the Backup Low
Power Mode. In this mode, the current consumption is reduced to a few microamps for Backup power retention.
Exit from this mode is possible on multiple wake-up sources including events on FWUP or WKUP pins, or a Clock
alarm. The SUPC also generates the Slow Clock by selecting either the Low Power RC oscillator or the Low Power
Crystal oscillator.
16.2 Embedded Characteristics
Manages the Core Power Supply VDDCORE and the Backup Low Power Mode by Controlling the
Embedded Voltage Regulator
Generates the Slow Clock SLCK, by Selecting Either the 22-42 kHz Low Power RC Oscillator or the 32 kHz
Low Power Crystal Oscillator
Supports Multiple Wake Up Sources, for Exit from Backup Low Power Mode
̶Force Wake Up Pin, with Programmable Debouncing
̶16 Wake Up Inputs, with Programmable Debouncing
̶Real Time Clock Alarm
̶Real Time Timer Alarm
̶Supply Monitor Detection on VDDUTMI, with Programmable Scan Period and Voltage Threshold
A Supply Monitor Detection on VDDUTMI or a Brownout Detection on VDDCORE can Trigger a Core Reset
Embeds:
̶One 22 to 42 kHz Low Power RC Oscillator
̶One 32 kHz Low Power Crystal Oscillator
̶One Zero-Power Power-On Reset Cell
̶One Software Programmable Supply Monitor, on VDDUTMI Located in Backup Section
̶One Brownout Detector on VDDCORE Located in the Core
flw 4,: a: mm
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16.3 Block Diagram
Figure 16-1. Supply Controller Block Diagram
Software Controlled
Voltage Regulator
ADC (front-end)
DAC (front-end)
Matrix
SRAM
Watchdog
Timer
Flash
Peripherals
Peripheral
Bridge
Zero-Power
Power-on Reset
Supply
Monitor
RTC
Power
Management
Controller
Embedded
32 kHz RC
Oscillator
Xtal 32 kHz
Oscillator
Supply
Controller
Embedded
12 / 8 / 4 MHz
RC
Oscillator
Brownout
Detector
General Purpose
Backup Registers
Cortex-M3
Reset
Controller
Backup Power Supply
Core Power Supply
PLLA
vr_standby
vr_vdd
rtc_alarm
SLCK
proc_nreset
periph_nreset
ice_nreset
Master Clock
MCK
SLCK
vddcore_nreset
Main Clock
MAINCK
SLCK
NRST
MAINCK PLLACK
FSTT0 - FSTT15(1)
XIN32
XOUT32
osc32k_xtal_en
XTALSEL
Slow Clock
SLCK
osc32k_rc_en
vddcore_nreset
VDDIO
VDDCORE
VDDOUT
ADVREF
ADx
FWUP
bodcore_on
bodcore_in
RTT
rtt_alarm
SLCK
XIN
XOUT
VDDBU VDDIN
SHDN
PIOx
VDDANA
USB
VDDUTMI
USBx
vr_deep
sm_in
sm_on
supc_interrupt
3 - 20 MHz
XTAL Oscillator
WKUP0 - WKUP15
NRSTB
PIOA/B/C
Input / Output Buffers
FSTT0 - FSTT15 are possible Fast Startup Sources, generated by WKUP0-WKUP15 Pins,
but are not physical pins.
UPLL
MAINCK UPLLCK
DACx
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16.4 Supply Controller Functional Description
16.4.1 Supply Controller Overview
The device can be divided into two power supply areas:
The Backup VDDBU Power Supply: including the Supply Controller, a part of the Reset Controller, the Slow
Clock switch, the General Purpose Backup Registers, the Supply Monitor and the Clock which includes the
Real Time Timer and the Real Time Clock
The Core Power Supply: including the other part of the Reset Controller, the Brownout Detector, the
Processor, the SRAM memory, the FLASH memory and the Peripherals
The Supply Controller (SUPC) controls the supply voltage of the core power supply. The SUPC intervenes when
the VDDUTMI power supply rises (when the system is starting) or when the Backup Low Power Mode is entered.
The SUPC also integrates the Slow Clock generator which is based on a 32 kHz crystal oscillator and an
embedded 32 kHz RC oscillator. The Slow Clock defaults to the RC oscillator, but the software can enable the
crystal oscillator and select it as the Slow Clock source.
The Supply Controller and the VDDUTMI power supply have a reset circuitry based on the NRSTB pin and a zero-
power power-on reset cell. The zero-power power-on reset allows the SUPC to start properly as soon as the
VDDUTMI voltage becomes valid. The NRSTB pin allows to reset the system from outside.
At startup of the system, once the backup voltage VDDUTMI is valid and the reset pin NRSTB is not driven low and
the embedded 32 kHz RC oscillator is stabilized, the SUPC starts up the core by sequentially enabling the internal
Voltage Regulator, waiting that the core voltage VDDCORE is valid, then releasing the reset signal of the core
“vddcore_nreset” signal.
Once the system has started, the user can program a supply monitor and/or a brownout detector. If the supply
monitor detects a voltage on VDDUTMI that is too low, the SUPC can assert the reset signal of the core
“vddcore_nreset” signal until VDDUTMI is valid. Likewise, if the brownout detector detects a core voltage
VDDCORE that is too low, the SUPC can assert the reset signal “vddcore_nreset” until VDDCORE is valid.
When the Backup Low Power Mode is entered, the SUPC sequentially asserts the reset signal of the core power
supply “vddcore_nreset” and disables the voltage regulator, in order to supply only the VDDUTMI power supply. In
this mode the current consumption is reduced to a few microamps for Backup part retention. Exit from this mode is
possible on multiple wake-up sources including an event on FWUP pin or WKUP pins, or a Clock alarm. To exit
this mode, the SUPC operates in the same way as system startup.
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16.4.2 Slow Clock Generator
The Supply Controller embeds a slow clock generator that is supplied with the VDDBU power supply. As soon as
the VDDBU is supplied, both the crystal oscillator and the embedded RC oscillator are powered up, but only the
embedded RC oscillator is enabled. This allows the slow clock to be valid in a short time (about 100 µs).
The user can select the crystal oscillator to be the source of the slow clock, as it provides a more accurate
frequency. The command is made by writing the Supply Controller Control Register (SUPC_CR) with the
XTALSEL bit at 1. This results in a sequence which first enables the crystal oscillator, then waits for 32,768 slow
clock cycles, then switches the slow clock on the output of the crystal oscillator and then disables the RC oscillator
to save power. The switch of the slow clock source is glitch free. The OSCSEL bit of the Supply Controller Status
Register (SUPC_SR) allows knowing when the switch sequence is done.
Coming back on the RC oscillator is only possible by shutting down the VDDBU power supply.
If the user does not need the crystal oscillator, the XIN32 and XOUT32 pins should be left unconnected.
The user can also set the crystal oscillator in bypass mode instead of connecting a crystal. In this case, the user
has to provide the external clock signal on XIN32. The input characteristics of the XIN32 pin are given in the
product electrical characteristics section. In order to set the bypass mode, the OSCBYPASS bit of the Supply
Controller Mode Register (SUPC_MR) needs to be set at 1.
16.4.3 Voltage Regulator Control/Backup Low Power Mode
The Supply Controller can be used to control the embedded 1.8V voltage regulator.
The voltage regulator automatically adapts its quiescent current depending on the required load current. Please
refer to the electrical characteristics section.
The programmer can switch off the voltage regulator, and thus put the device in Backup mode, by writing the
Supply Controller Control Register (SUPC_CR) with the VROFF bit at 1.
This can be done also by using WFE (Wait for Event) Cortex-M3 instruction with the deep mode bit set to 1.
The Backup mode can also be entered by executing the WFI (Wait for Interrupt) or WFE (Wait for Event) Cortex-
M3 instructions. To select the Backup mode entry mechanism, two options are available, depending on the
SLEEPONEXIT bit in the Cortex-M3 System Control register:
Sleep-now: if the SLEEPONEXIT bit is cleared, the device enters Backup mode as soon as the WFI or WFE
instruction is executed.
Sleep-on-exit: if the SLEEPONEXIT bit is set when the WFI instruction is executed, the device enters
Backup mode as soon as it exits the lowest priority ISR.
This asserts the vddcore_nreset signal after the write resynchronization time which lasts, in the worse case, two
slow clock cycles. Once the vddcore_nreset signal is asserted, the processor and the peripherals are stopped one
slow clock cycle before the core power supply shuts off.
When the user does not use the internal voltage regulator and wants to supply VDDCORE by an external supply, it
is possible to disable the voltage regulator. Note that it is different from the Backup mode. Depending on the
application, disabling the voltage regulator can reduce power consumption as the voltage regulator input (VDDIN)
is shared with the ADC and DAC. This is done through ONREG bit in SUPC_MR.
16.4.4 Using Backup Batteries/Backup Supply
The product can be used with or without backup batteries, or more generally a backup supply. When a backup
supply is used (See Figure 16-2), only VDDBU voltage is present in Backup mode and no other external supply is
applied on the chip. In this case the user needs to clear VDDIORDY bit in the Supply Controller Mode Register
(SUPC_MR) at least two slow clock periods before VDDIO voltage is removed. When waking up from Backup
mode, the programmer needs to set VDDIORDY.
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Figure 16-2. Separated Backup Supply Powering Scheme
Note: Restrictions: With Main Supply < 3V, some peripherals such as USB and ADC might not be operational. Refer to the
DC Characteristics of the product for actual possible ranges for such peripherals.
When a separated backup supply for VDDBU is not used (See Figure 16-3), since the external voltage applied on
VDDIO is kept, all of the I/O configurations (i.e. WKUP pin configuration) are kept during backup mode. When not
using backup batteries, VDDIORDY is set so the user does not need to program it.
VDDBU
VDDIN
Voltage
Regulator
VDDOUT
Main Supply (1.8V-3.6V)
VDDCORE
Backup Batteries
VDDIO
VDDANA
VDDUTMI
VDDPLL
FWUP
SHDN
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Figure 16-3. No Separated Backup Supply Powering Scheme
Note: Restrictions: With Main Supply < 3V, some peripherals such as USB and ADC might not be operational. Refer to the
DC Characteristics of the product for actual possible ranges for such peripherals.
16.4.5 Supply Monitor
The Supply Controller embeds a supply monitor which is located in the VDDBU Backup Power Supply and which
monitors VDDUTMI power supply.
The supply monitor can be used to prevent the processor from falling into an unpredictable state if the Main power
supply drops below a certain level.
The threshold of the supply monitor is programmable. It can be selected from 1.9V to 3.4V by steps of 100 mV.
This threshold is programmed in the SMTH field of the Supply Controller Supply Monitor Mode Register
(SUPC_SMMR).
The supply monitor can also be enabled during one slow clock period on every one of either 32, 256 or 2048 slow
clock periods, according to the choice of the user. This can be configured by programming the SMSMPL field in
SUPC_SMMR.
Enabling the supply monitor for such reduced times allows to divide the typical supply monitor power consumption
respectively by factors of 32, 256 or 2048, if the user does not need a continuous monitoring of the VDDUTMI
power supply.
A supply monitor detection can either generate a reset of the core power supply or a wake up of the core power
supply. Generating a core reset when a supply monitor detection occurs is enabled by writing the SMRSTEN bit to
1 in SUPC_SMMR.
VDDBU
VDDIN
Voltage
Regulator
VDDOUT
Main Supply (1.8V-3.6V)
VDDCORE
VDDIO
VDDANA
VDDUTMI
VDDPLL
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Waking up the core power supply when a supply monitor detection occurs can be enabled by programming the
SMEN bit to 1 in the Supply Controller Wake Up Mode Register (SUPC_WUMR).
The Supply Controller provides two status bits in the Supply Controller Status Register for the supply monitor
which allows to determine whether the last wake up was due to the supply monitor:
The SMOS bit provides real time information, which is updated at each measurement cycle or updated at
each Slow Clock cycle, if the measurement is continuous.
The SMS bit provides saved information and shows a supply monitor detection has occurred since the last
read of SUPC_SR.
The SMS bit can generate an interrupt if the SMIEN bit is set to 1 in the Supply Controller Supply Monitor Mode
Register (SUPC_SMMR).
Figure 16-4. Supply Monitor Status Bit and Associated Interrupt
Supply Monitor ON
3.3 V
0 V
Threshold
SMS and SUPC interrupt
Read SUPC_SR
Periodic Sampling
Continuous Sampling (SMSMPL = 1)
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16.4.6 Backup Power Supply Reset
16.4.6.1 Raising the Backup Power Supply
As soon as the backup voltage VDDUTMI rises, the RC oscillator is powered up and the zero-power power-on
reset cell maintains its output low as long as VDDUTMI has not reached its target voltage. During this time, the
Supply Controller is entirely reset. When the VDDUTMI voltage becomes valid and zero-power power-on reset
signal is released, a counter is started for 5 slow clock cycles. This is the time it takes for the 32 kHz RC oscillator
to stabilize.
After this time, the SHDN pin is asserted and the voltage regulator is enabled. The core power supply rises and the
brownout detector provides the bodcore_in signal as soon as the core voltage VDDCORE is valid. This results in
releasing the vddcore_nreset signal to the Reset Controller after the bodcore_in signal has been confirmed as
being valid for at least one slow clock cycle.
Figure 16-5. Raising the VDDUTMI Power Supply
16.4.6.2 NRSTB Asynchronous Reset Pin
The NRSTB pin is an asynchronous reset input, which acts exactly like the zero-power power-on reset cell.
As soon as NRSTB is tied to GND, the supply controller is reset generating in turn, a reset of the whole system.
When NRSTB is released, the system can start as described in Section 16.4.6.1 ”Raising the Backup Power
Supply”.
Zero-Power Power-On
Reset Cell output
22 - 42 kHz RC
Oscillator output
Fast RC
Oscillator output
Backup Power Supply
SHDN / vr_on
bodcore_in
vddcore_nreset
NRST
proc_nreset
Note: After “proc_nreset” rising, the core starts fecthing instructions from Flash at 4 MHz.
periph_nreset
7 x Slow Clock Cycles 3 x Slow Clock
Cycles 3 x Slow Clock
Cycles 6.5 x Slow Clock
Cycles
TON Voltage
Regulator
Zero-Power POR
Core Power Supply
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The NRSTB pin does not need to be driven during power-up phase to allow a reset of the system, it is done by the
zero-power power-on cell.
Figure 16-6. NRSTB Reset
Note: periph_nreset, ice_reset and proc_nreset are not shown, but are asserted low thanks to the vddcore_nreset signal controlling the
Reset controller.
16.4.6.3 SHDN output pin
As shown in Figure 16-6, the SHDN pin acts like the vr_standby signal making it possible to use the SHDN pin to
control external voltage regulator with shutdown capabilities.
16.4.7 Core Reset
The Supply Controller manages the vddcore_nreset signal to the Reset Controller, as described previously in
Section 16.4.6 ”Backup Power Supply Reset”. The vddcore_nreset signal is normally asserted before shutting
down the core power supply and released as soon as the core power supply is correctly regulated.
There are two additional sources which can be programmed to activate vddcore_nreset:
a supply monitor detection
a brownout detection
16.4.7.1 Supply Monitor Reset
The supply monitor is capable of generating a reset of the system. This can be enabled by setting the SMRSTEN
bit in the Supply Controller Supply Monitor Mode Register (SUPC_SMMR).
If SMRSTEN is set and if a supply monitor detection occurs, the vddcore_nreset signal is immediately activated for
a minimum of 1 slow clock cycle.
16.4.7.2 Brownout Detector Reset
The brownout detector provides the bodcore_in signal to the SUPC which indicates that the voltage regulation is
operating as programmed. If this signal is lost for longer than 1 slow clock period while the voltage regulator is
enabled, the Supply Controller can assert vddcore_nreset. This feature is enabled by writing the bit, BODRSTEN
(Brownout Detector Reset Enable) to 1 in the Supply Controller Mode Register (SUPC_MR).
If BODRSTEN is set and the voltage regulation is lost (output voltage of the regulator too low), the vddcore_nreset
signal is asserted for a minimum of 1 slow clock cycle and then released if bodcore_in has been reactivated. The
BODRSTS bit is set in the Supply Controller Status Register (SUPC_SR) so that the user can know the source of
the last reset.
Until bodcore_in is deactivated, the vddcore_nreset signal remains active.
30 Slow Clock Cycles = about 1ms between 2 and 3 Slow Clock Cycles
32 kHz Low Power Crystal
Oscillator output
NRSTB
SHDN / vr_standby
bodcore_in
vddcore_nreset
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16.4.8 Wake Up Sources
The wake up events allow the device to exit backup mode. When a wake up event is detected, the Supply
Controller performs a sequence which automatically reenables the core power supply.
Figure 16-7. Wake Up Source
16.4.8.1 Force Wake Up
The FWUP pin is enabled as a wake up source by writing the FWUPEN bit to 1 in the Supply Controller Wake Up
Mode Register (SUPC_WUMR). Then, the FWUPDBC field in the same register selects the debouncing period,
which can be selected between 3, 32, 512, 4,096 or 32,768 slow clock cycles. This corresponds respectively to
about 100 µs, about 1 ms, about 16 ms, about 128 ms and about 1 second (for a typical slow clock frequency of 32
kHz). Programming FWUPDBC to 0x0 selects an immediate wake up, i.e., the FWUP must be low during a
minimum of one slow clock period to wake up the core power supply.
If the FWUP pin is asserted for a time longer than the debouncing period, a wake up of the core power supply is
started and the FWUP bit in the Supply Controller Status Register (SUPC_SR) is set and remains high until the
register is read.
16.4.8.2 Wake Up Inputs
The wake up inputs, WKUP0 to WKUP15, can be programmed to perform a wake up of the core power supply.
Each input can be enabled by writing to 1 the corresponding bit, WKUPEN0 to WKUPEN 15, in the Wake Up
Inputs Register (SUPC_WUIR). The wake up level can be selected with the corresponding polarity bit, WKUPPL0
to WKUPPL15, also located in SUPC_WUIR.
WKUP15
FWUP
rtt_alarm
rtc_alarm
sm_int
WKUP0
WKUP1
WKUPT1
Core
Supply
Restart
Debouncer
WKUPDBC
WKUPS
Debouncer
FWUPDBC
FWUP
WKUPIS0
WKUPIS1
WKUPIS15
RTTEN
RTCEN
SMEN
WKUPEN15
WKUPEN1
WKUPEN0
FWUPEN
WKUPT15
Falling/Rising
Edge
Detector
WKUPT0
Falling/Rising
Edge
Detector
Falling/Rising
Edge
Detector
Falling
Edge
Detector
SLCK
SLCK
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All the resulting signals are wired-ORed to trigger a debounce counter, which can be programmed with the
WKUPDBC field in the Supply Controller Wake Up Mode Register (SUPC_WUMR). The WKUPDBC field can
select a debouncing period of 3, 32, 512, 4,096 or 32,768 slow clock cycles. This corresponds respectively to
about 100 µs, about 1 ms, about 16 ms, about 128 ms and about 1 second (for a typical slow clock frequency of 32
kHz). Programming WKUPDBC to 0x0 selects an immediate wake up, i.e., an enabled WKUP pin must be active
according to its polarity during a minimum of one slow clock period to wake up the core power supply.
If an enabled WKUP pin is asserted for a time longer than the debouncing period, a wake up of the core power
supply is started and the signals, WKUP0 to WKUP15 as shown in Figure 16-7, are latched in the Supply
Controller Status Register (SUPC_SR). This allows the user to identify the source of the wake up, however, if a
new wake up condition occurs, the primary information is lost. No new wake up can be detected since the primary
wake up condition has disappeared.
16.4.8.3 Clock Alarms
The RTC and the RTT alarms can generate a wake up of the core power supply. This can be enabled by writing
respectively, the bits RTCEN and RTTEN to 1 in the Supply Controller Wake Up Mode Register (SUPC_WUMR).
The Supply Controller does not provide any status as the information is available in the User Interface of either the
Real Time Timer or the Real Time Clock.
16.4.8.4 Supply Monitor Detection
The supply monitor can generate a wakeup of the core power supply. See Section 16.4.5 ”Supply Monitor”.
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16.5 Supply Controller (SUPC) User Interface
The User Interface of the Supply Controller is part of the System Controller User Interface.
16.5.1 System Controller (SYSC) User Interface
16.5.2 System Controller (SYSC) User Interface
Table 16-1. System Controller Registers
Offset System Controller Peripheral Name
0x00-0x0c Reset Controller RSTC
0x10-0x2C Supply Controller SUPC
0x30-0x3C Real Time Timer RTT
0x50-0x5C Watchdog WDT
0x60-0x7C Real Time Clock RTC
0x90-0xDC General Purpose Backup Register GPBR
Table 16-2. Register Mapping
Offset Register Name Access Reset
0x00 Supply Controller Control Register SUPC_CR Write-only N/A
0x04 Supply Controller Supply Monitor Mode Register SUPC_SMMR Read-write 0x0000_0000
0x08 Supply Controller Mode Register SUPC_MR Read-write 0x0000_5A00
0x0C Supply Controller Wake Up Mode Register SUPC_WUMR Read-write 0x0000_0000
0x10 Supply Controller Wake Up Inputs Register SUPC_WUIR Read-write 0x0000_0000
0x14 Supply Controller Status Register SUPC_SR Read-only 0x0000_0800
0x18 Reserved
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16.5.3 Supply Controller Control Register
Name: SUPC_CR
Address: 0x400E1A10
Access: Write-only
• VROFF: Voltage Regulator Off
0 (NO_EFFECT) = no effect.
1 (STOP_VREG) = if KEY is correct, asserts vddcore_nreset and stops the voltage regulator.
• XTALSEL: Crystal Oscillator Select
0 (NO_EFFECT) = no effect.
1 (CRYSTAL_SEL) = if KEY is correct, switches the slow clock on the crystal oscillator output.
• KEY: Password
Should be written to value 0xA5. Writing any other value in this field aborts the write operation.
31 30 29 28 27 26 25 24
KEY
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––– –
76543210
––––XTALSELVROFF––
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16.5.4 Supply Controller Supply Monitor Mode Register
Name: SUPC_SMMR
Address: 0x400E1A14
Access: Read-write
• SMTH: Supply Monitor Threshold
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – SMIEN SMRSTEN – SMSMPL
76543210
–––– SMTH
Value Name Description
0x0 1_9V 1.9 V
0x1 2_0V 2.0 V
0x2 2_1V 2.1 V
0x3 2_2V 2.2 V
0x4 2_3V 2.3 V
0x5 2_4V 2.4 V
0x6 2_5V 2.5 V
0x7 2_6V 2.6 V
0x8 2_7V 2.7 V
0x9 2_8V 2.8 V
0xA 2_9V 2.9 V
0xB 3_0V 3.0 V
0xC 3_1V 3.1 V
0xD 3_2V 3.2 V
0xE 3_3V 3.3 V
0xF 3_4V 3.4 V
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• SMSMPL: Supply Monitor Sampling Period
• SMRSTEN: Supply Monitor Reset Enable
0 (NOT_ENABLE) = the core reset signal “vddcore_nreset” is not affected when a supply monitor detection occurs.
1 (ENABLE) = the core reset signal, vddcore_nreset is asserted when a supply monitor detection occurs.
• SMIEN: Supply Monitor Interrupt Enable
0 (NOT_ENABLE) = the SUPC interrupt signal is not affected when a supply monitor detection occurs.
1 (ENABLE) = the SUPC interrupt signal is asserted when a supply monitor detection occurs.
Value Name Description
0x0 SMD Supply Monitor disabled
0x1 CSM Continuous Supply Monitor
0x2 32SLCK Supply Monitor enabled one SLCK period every 32 SLCK periods
0x3 256SLCK Supply Monitor enabled one SLCK period every 256 SLCK periods
0x4 2048SLCK Supply Monitor enabled one SLCK period every 2,048 SLCK periods
0x5-0x7 Reserved Reserved
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16.5.5 Supply Controller Mode Register
Name: SUPC_MR
Address: 0x400E1A18
Access: Read-write
• BODRSTEN: Brownout Detector Reset Enable
0 (NOT_ENABLE) = the core reset signal “vddcore_nreset” is not affected when a brownout detection occurs.
1 (ENABLE) = the core reset signal, vddcore_nreset is asserted when a brownout detection occurs.
• BODDIS: Brownout Detector Disable
0 (ENABLE) = the core brownout detector is enabled.
1 (DISABLE) = the core brownout detector is disabled.
• VDDIORDY: VDDIO Ready
0 (VDDIO_REMOVED) = VDDIO is removed (used before going to backup mode when backup batteries are used)
1 (VDDIO_PRESENT) = VDDIO is present (used before going to backup mode when backup batteries are used)
If the backup batteries are not used, VDDIORDY must be kept set to 1.
• ONREG: Voltage Regulator enable
0 (ONREG_UNUSED) = Voltage Regulator is not used
1 (ONREG_USED) = Voltage Regulator is used
• OSCBYPASS: Oscillator Bypass
0 (NO_EFFECT) = no effect. Clock selection depends on XTALSEL value.
1 (BYPASS) = the 32-KHz XTAL oscillator is selected and is put in bypass mode.
• KEY: Password Key
Should be written to value 0xA5. Writing any other value in this field aborts the write operation.
31 30 29 28 27 26 25 24
KEY
23 22 21 20 19 18 17 16
–––OSCBYPASS––––
15 14 13 12 11 10 9 8
–VDDIORDY
ONREG BODDISBODRSTEN––––
76543210
––––––––
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16.5.6 Supply Controller Wake Up Mode Register
Name: SUPC_WUMR
Address: 0x400E1A1C
Access: Read-write
• FWUPEN: Force Wake Up Enable
0 (NOT_ENABLE) = the Force Wake Up pin has no wake up effect.
1 (ENABLE) = the Force Wake Up pin low forces the wake up of the core power supply.
• SMEN: Supply Monitor Wake Up Enable
0 (NOT_ENABLE) = the supply monitor detection has no wake up effect.
1 (ENABLE) = the supply monitor detection forces the wake up of the core power supply.
• RTTEN: Real Time Timer Wake Up Enable
0 (NOT_ENABLE) = the RTT alarm signal has no wake up effect.
1 (ENABLE) = the RTT alarm signal forces the wake up of the core power supply.
• RTCEN: Real Time Clock Wake Up Enable
0 (NOT_ENABLE) = the RTC alarm signal has no wake up effect.
1 (ENABLE) = the RTC alarm signal forces the wake up of the core power supply.
• FWUPDBC: Force Wake Up Debouncer Period
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– WKUPDBC – FWUPDBC
76543210
––––RTCENRTTENSMENFWUPEN
Value Name Description
0 IMMEDIATE Immediate, no debouncing, detected active at least on one Slow Clock edge.
1 3_SCLK FWUP shall be low for at least 3 SLCK periods
2 32_SCLK FWUP shall be low for at least 32 SLCK periods
3 512_SCLK FWUP shall be low for at least 512 SLCK periods
4 4096_SCLK FWUP shall be low for at least 4,096 SLCK periods
5 32768_SCLK FWUP shall be low for at least 32,768 SLCK periods
6 Reserved Reserved
7 Reserved Reserved
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• WKUPDBC: Wake Up Inputs Debouncer Period
Value Name Description
0 IMMEDIATE Immediate, no debouncing, detected active at least on one Slow Clock edge.
1 3_SCLK WKUPx shall be in its active state for at least 3 SLCK periods
2 32_SCLK WKUPx shall be in its active state for at least 32 SLCK periods
3 512_SCLK WKUPx shall be in its active state for at least 512 SLCK periods
4 4096_SCLK WKUPx shall be in its active state for at least 4,096 SLCK periods
5 32768_SCLK WKUPx shall be in its active state for at least 32,768 SLCK periods
6 Reserved Reserved
7 Reserved Reserved
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16.5.7 System Controller Wake Up Inputs Register
Name: SUPC_WUIR
Address: 0x400E1A20
Access: Read-write
• WKUPEN0 - WKUPEN15: Wake Up Input Enable 0 to 15
0 (NOT_ENABLE) = the corresponding wake-up input has no wake up effect.
1 (ENABLE) = the corresponding wake-up input forces the wake up of the core power supply.
• WKUPT0 - WKUPT15: Wake Up Input Transition 0 to 15
0 (HIGH_TO_LOW) = a high to low level transition on the corresponding wake-up input forces the wake up of the core
power supply.
1 (LOW_TO_HIGH) = a low to high level transition on the corresponding wake-up input forces the wake up of the core
power supply.
31 30 29 28 27 26 25 24
WKUPT15 WKUPT14 WKUPT13 WKUPT12 WKUPT11 WKUPT10 WKUPT9 WKUPT8
23 22 21 20 19 18 17 16
WKUPT7 WKUPT6 WKUPT5 WKUPT4 WKUPT3 WKUPT2 WKUPT1 WKUPT0
15 14 13 12 11 10 9 8
WKUPEN15 WKUPEN14 WKUPEN13 WKUPEN12 WKUPEN11 WKUPEN10 WKUPEN9 WKUPEN8
76543210
WKUPEN7 WKUPEN6 WKUPEN5 WKUPEN4 WKUPEN3 WKUPEN2 WKUPEN1 WKUPEN0
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16.5.8 Supply Controller Status Register
Name: SUPC_SR
Address: 0x400E1A24
Access: Read-write
Note: Because of the asynchronism between the Slow Clock (SCLK) and the System Clock (MCK), the status register flag reset is taken
into account only 2 slow clock cycles after the read of the SUPC_SR.
• FWUPS: FWUP Wake Up Status
0 (NO) = no wake up due to the assertion of the FWUP pin has occurred since the last read of SUPC_SR.
1 (PRESENT) = at least one wake up due to the assertion of the FWUP pin has occurred since the last read of SUPC_SR.
• WKUPS: WKUP Wake Up Status
0 (NO) = no wake up due to the assertion of the WKUP pins has occurred since the last read of SUPC_SR.
1 (PRESENT) = at least one wake up due to the assertion of the WKUP pins has occurred since the last read of
SUPC_SR.
• SMWS: Supply Monitor Detection Wake Up Status
0 (NO) = no wake up due to a supply monitor detection has occurred since the last read of SUPC_SR.
1 (PRESENT) = at least one wake up due to a supply monitor detection has occurred since the last read of SUPC_SR.
• BODRSTS: Brownout Detector Reset Status
0 (NO) = no core brownout rising edge event has been detected since the last read of the SUPC_SR.
1 (PRESENT) = at least one brownout output rising edge event has been detected since the last read of the SUPC_SR.
When the voltage remains below the defined threshold, there is no rising edge event at the output of the brownout detec-
tion cell. The rising edge event occurs only when there is a voltage transition below the threshold.
• SMRSTS: Supply Monitor Reset Status
0 (NO) = no supply monitor detection has generated a core reset since the last read of the SUPC_SR.
1 (PRESENT) = at least one supply monitor detection has generated a core reset since the last read of the SUPC_SR.
• SMS: Supply Monitor Status
0 (NO) = no supply monitor detection since the last read of SUPC_SR.
1 (PRESENT) = at least one supply monitor detection since the last read of SUPC_SR.
31 30 29 28 27 26 25 24
WKUPIS15 WKUPIS14 WKUPIS13 WKUPIS12 WKUPIS11 WKUPIS10 WKUPIS9 WKUPIS8
23 22 21 20 19 18 17 16
WKUPIS7 WKUPIS6 WKUPIS5 WKUPIS4 WKUPIS3 WKUPIS2 WKUPIS1 WKUPIS0
15 14 13 12 11 10 9 8
–––FWUPIS––––
76543210
OSCSEL SMOS SMS SMRSTS BODRSTS SMWS WKUPS FWUPS
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• SMOS: Supply Monitor Output Status
0 (HIGH) = the supply monitor detected VDDUTMI higher than its threshold at its last measurement.
1 (LOW) = the supply monitor detected VDDUTMI lower than its threshold at its last measurement.
• OSCSEL: 32-kHz Oscillator Selection Status
0 (RC) = the slow clock, SLCK is generated by the embedded 32-kHz RC oscillator.
1 (CRYST) = the slow clock, SLCK is generated by the 32-kHz crystal oscillator.
• FWUPIS: FWUP Input Status
0 (LOW) = FWUP input is tied low.
1 (HIGH) = FWUP input is tied high.
• WKUPIS0-WKUPIS15: WKUP Input Status 0 to 15
0 (DIS) = the corresponding wake-up input is disabled, or was inactive at the time the debouncer triggered a wake up
event.
1 (EN) = the corresponding wake-up input was active at the time the debouncer triggered a wake up event.
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17. General Purpose Backup Registers (GPBR)
17.1 Description
The System Controller embeds Eight general-purpose backup registers.
17.2 Embedded Characteristics
Eight 32-bit General Purpose Backup Registers
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17.3 General Purpose Backup Registers (GPBR) User Interface
Table 17-1. Register Mapping
Offset Register Name Access Reset
0x0 General Purpose Backup Register 0 SYS_GPBR0 Read-write –
... ... ... ... ...
0x1c General Purpose Backup Register 7 SYS_GPBR7 Read-write –
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17.3.1 General Purpose Backup Register x
Name: SYS_GPBRx
Address: 0x400E1A90 [0] .. 0x400E1AAC [7]
Access: Read-write
• GPBR_VALUEx: Value of GPBR x
3130292827 26 25 24
GPBR_VALUEx
2322 21 20 19 1817 16
GPBR_VALUEx
15 14 1312 11 10 9 8
GPBR_VALUEx
76543210
GPBR_VALUEx
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18. Enhanced Embedded Flash Controller (EEFC)
18.1 Description
The Enhanced Embedded Flash Controller (EEFC) ensures the interface of the Flash block with the 32-bit internal
bus.
Its 128-bit or 64-bit wide memory interface increases performance. It also manages the programming, erasing,
locking and unlocking sequences of the Flash using a full set of commands. One of the commands returns the
embedded Flash descriptor definition that informs the system about the Flash organization, thus making the
software generic.
18.2 Embedded Characteristics
Interface of the Flash Block with the 32-bit Internal Bus
Increases Performance in Thumb2® Mode with 128-bit or -64 bit Wide Memory Interface up to 23 MHz
16 Lock Bits, Each Protecting a Lock Region
3 General-purpose GPNVM Bits
One-by-one Lock Bit Programming
Commands Protected by a Keyword
Erases the Entire Flash
Possibility of Erasing before Programming
Locking and Unlocking Operations
Consecutive Programming and Locking Operations
Possibility to read the Calibration Bits
18.3 Product Dependencies
18.3.1 Power Management
The Enhanced Embedded Flash Controller (EEFC) is continuously clocked. The Power Management Controller
has no effect on its behavior.
18.3.2 Interrupt Sources
The Enhanced Embedded Flash Controller (EEFC) interrupt line is connected to the Nested Vectored Interrupt
Controller (NVIC). Using the Enhanced Embedded Flash Controller (EEFC) interrupt requires the NVIC to be
programmed first. The EEFC interrupt is generated only on FRDY bit rising.
Table 18-1. Peripheral IDs
Instance ID
EFC0 6
EFC1 7
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18.4 Functional Description
18.4.1 Embedded Flash Organization
The embedded Flash interfaces directly with the 32-bit internal bus. The embedded Flash is composed of:
One memory plane organized in several pages of the same size.
Two 128-bit or 64-bit read buffers used for code read optimization.
One 128-bit or 64-bit read buffer used for data read optimization.
One write buffer that manages page programming. The write buffer size is equal to the page size. This buffer
is write-only and accessible all along the 1 MByte address space, so that each word can be written to its final
address.
Several lock bits used to protect write/erase operation on several pages (lock region). A lock bit is
associated with a lock region composed of several pages in the memory plane.
Several bits that may be set and cleared through the Enhanced Embedded Flash Controller (EEFC)
interface, called General Purpose Non Volatile Memory bits (GPNVM bits).
The embedded Flash size, the page size, the lock regions organization and GPNVM bits definition are described in
the product definition section. The Enhanced Embedded Flash Controller (EEFC) returns a descriptor of the Flash
controlled after a get descriptor command issued by the application (see “Getting Embedded Flash Descriptor” on
page 297).
Figure 18-1. Embedded Flash Organization
Start Address
Page 0
Lock Region 0
Lock Region 1
Memory Plane
Page (m-1)
Lock Region (n-1)
Page (n*m-1)
Start Address + Flash size -1
Lock Bit 0
Lock Bit 1
Lock Bit (n-1)
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18.4.2 Read Operations
An optimized controller manages embedded Flash reads, thus increasing performance when the processor is
running in Thumb2 mode by means of the 128- or 64- bit wide memory interface.
The Flash memory is accessible through 8-, 16- and 32-bit reads.
As the Flash block size is smaller than the address space reserved for the internal memory area, the embedded
Flash wraps around the address space and appears to be repeated within it.
The read operations can be performed with or without wait states. Wait states must be programmed in the field
FWS (Flash Read Wait State) in the Flash Mode Register (EEFC_FMR). Defining FWS to be 0 enables the single-
cycle access of the embedded Flash. Refer to the Electrical Characteristics for more details.
18.4.2.1 128-bit or 64-bit Access Mode
By default the read accesses of the Flash are performed through a 128-bit wide memory interface. It enables
better system performance especially when 2 or 3 wait state needed.
For systems requiring only 1 wait state, or to privilege current consumption rather than performance, the user can
select a 64-bit wide memory access via the FAM bit in the Flash Mode Register (EEFC_FMR)
Please refer to the electrical characteristics section of the product datasheet for more details.
18.4.2.2 Code Read Optimization
A system of 2 x 128-bit or 2 x 64-bit buffers is added in order to optimize sequential Code Fetch.
Note: Immediate consecutive code read accesses are not mandatory to benefit from this optimization.
Figure 18-2. Code Read Optimization for FWS = 0
Note: When FWS is equal to 0, all the accesses are performed in a single-cycle access.
Flash Access
Buffer 0 (128bits)
Master Clock
ARM Request
(32-bit)
XXX
Data To ARM
Bytes 0-15 Bytes 16-31 Bytes 32-47
Bytes 0-15
Buffer 1 (128bits)
Bytes 32-47
Bytes 0-3Bytes 4-7 Bytes 8-11 Bytes 12-15 Bytes 16-19 Bytes 20-23Bytes 24-27
XXX
XXX Bytes 16-31
@Byte 0 @Byte 4 @Byte 8@Byte 12 @Byte 16 @Byte 20 @Byte 24 @Byte 28@Byte 32
Bytes 28-31
W T TTTTTTTTTTTTT X X X X x X x X X:XXXX_XXXXXXXX J|||||||||I_|||l_\||||||||| T TTTT TTTT T X X X X X X X X X XXXXXXXXXXX AtmeL
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Figure 18-3. Code Read Optimization for FWS = 3
Note: When FWS is included between 1 and 3, in case of sequential reads, the first access takes (FWS+1) cycles, the other ones only
1 cycle.
18.4.2.3 Data Read Optimization
The organization of the Flash in 128 bits (or 64 bits) is associated with two 128-bit (or 64-bit) prefetch buffers and
one 128-bit (or 64-bit) data read buffer, thus providing maximum system performance. This buffer is added in order
to store the requested data plus all the data contained in the 128-bit (64-bit) aligned data. This speeds up
sequential data reads if, for example, FWS is equal to 1 (see Figure 18-4).
Note: No consecutive data read accesses are mandatory to benefit from this optimization.
Figure 18-4. Data Read Optimization for FWS = 1
18.4.3 Flash Commands
The Enhanced Embedded Flash Controller (EEFC) offers a set of commands such as programming the memory
Flash, locking and unlocking lock regions, consecutive programming and locking and full Flash erasing, etc.
Flash Access
Buffer 0 (128bits)
Master Clock
ARM Request
(32-bit)
Data To ARM
Buffer 1 (128bits)
0-3
XXX
XXX
Bytes 16-31
@Byte 0 @4 @8
Bytes 0-15 Bytes 16-31 Bytes 32-47 Bytes 48-63
XXX Bytes 0-15
4-7 8-11 12-15
@12 @16 @20
24-27 28-3132-3536-3916-19 20-2340-4344-47
@24 @28@32@36 @40 @44 @48@52
Bytes 32-47
48-51
Flash Access
Buffer (128bits)
Master Clock
ARM Request
(32-bit)
XXX
Data To ARM
Bytes 0-15 Bytes 16-31
Bytes 0-15
Bytes 0-34-7 8-11 12-15 16-19 20-23
XXX
Bytes 16-31
@Byte 0 @ 4 @ 8@ 12 @ 16 @ 20 @ 24 @ 28@ 32@ 36
XXX Bytes 32-47
24-27 28-3132-35
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Commands and read operations can be performed in parallel only on different memory planes. Code can be
fetched from one memory plane while a write or an erase operation is performed on another.
In order to perform one of these commands, the Flash Command Register (EEFC_FCR) has to be written with the
correct command using the FCMD field. As soon as the EEFC_FCR register is written, the FRDY flag and the
FVALUE field in the EEFC_FRR register are automatically cleared. Once the current command is achieved,
then the FRDY flag is automatically set. If an interrupt has been enabled by setting the FRDY bit in EEFC_FMR,
the corresponding interrupt line of the NVIC is activated. (Note that this is true for all commands except for the
STUI Command. The FRDY flag is not set when the STUI command is achieved.)
All the commands are protected by the same keyword, which has to be written in the 8 highest bits of the
EEFC_FCR register.
Writing EEFC_FCR with data that does not contain the correct key and/or with an invalid command has no effect
on the whole memory plane, but the FCMDE flag is set in the EEFC_FSR register. This flag is automatically
cleared by a read access to the EEFC_FSR register.
When the current command writes or erases a page in a locked region, the command has no effect on the whole
memory plane, but the FLOCKE flag is set in the EEFC_FSR register. This flag is automatically cleared by a read
access to the EEFC_FSR register.
Table 18-2. Set of Commands
Command Value Mnemonic
Get Flash Descriptor 0x00 GETD
Write page 0x01 WP
Write page and lock 0x02 WPL
Erase page and write page 0x03 EWP
Erase page and write page then lock 0x04 EWPL
Erase all 0x05 EA
Set Lock Bit 0x08 SLB
Clear Lock Bit 0x09 CLB
Get Lock Bit 0x0A GLB
Set GPNVM Bit 0x0B SGPB
Clear GPNVM Bit 0x0C CGPB
Get GPNVM Bit 0x0D GGPB
Start Read Unique Identifier 0x0E STUI
Stop Read Unique Identifier 0x0F SPUI
Get CALIB Bit 0x10 GCALB
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Figure 18-5. Command State Chart
18.4.3.1 Getting Embedded Flash Descriptor
This command allows the system to learn about the Flash organization. The system can take full advantage of this
information. For instance, a device could be replaced by one with more Flash capacity, and so the software is able
to adapt itself to the new configuration.
To get the embedded Flash descriptor, the application writes the GETD command in the EEFC_FCR register. The
first word of the descriptor can be read by the software application in the EEFC_FRR register as soon as the
FRDY flag in the EEFC_FSR register rises. The next reads of the EEFC_FRR register provide the following word
of the descriptor. If extra read operations to the EEFC_FRR register are done after the last word of the descriptor
has been returned, then the EEFC_FRR register value is 0 until the next valid command.
Check if FRDY flag Set No
Yes
Read Status: MC_FSR
Write FCMD and PAGENB in Flash Command Register
Check if FLOCKE flag Set
Check if FRDY flag Set No
Read Status: MC_FSR
Yes
YesLocking region violation
No
Check if FCMDE flag Set Yes
No
Bad keyword violation
Command Successfull
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18.4.3.2 Write Commands
Several commands can be used to program the Flash.
Flash technology requires that an erase is done before programming. The full memory plane can be erased at the
same time, or several pages can be erased at the same time (refer to Section ”The Partial Programming mode
works only with 128-bit (or higher) boundaries. It cannot be used with boundaries lower than 128 bits (8, 16 or 32-
bit for example).”). Also, a page erase can be automatically done before a page write using EWP or EWPL
commands.
After programming, the page (the whole lock region) can be locked to prevent miscellaneous write or erase
sequences. The lock bit can be automatically set after page programming using WPL or EWPL commands.
Data to be written are stored in an internal latch buffer. The size of the latch buffer corresponds to the page size.
The latch buffer wraps around within the internal memory area address space and is repeated as many times as
the number of pages within this address space.
Note: Writing of 8-bit and 16-bit data is not allowed and may lead to unpredictable data corruption.
Write operations are performed in a number of wait states equal to the number of wait states for read operations.
Data are written to the latch buffer before the programming command is written to the Flash Command Register
EEFC_FCR. The sequence is as follows:
Write the full page, at any page address, within the internal memory area address space.
Programming starts as soon as the page number and the programming command are written to the Flash
Command Register. The FRDY bit in the Flash Programming Status Register (EEFC_FSR) is automatically
cleared.
When programming is completed, the FRDY bit in the Flash Programming Status Register (EEFC_FSR)
rises. If an interrupt has been enabled by setting the bit FRDY in EEFC_FMR, the corresponding interrupt
line of the NVIC is activated.
Two errors can be detected in the EEFC_FSR register after a programming sequence:
a Command Error: a bad keyword has been written in the EEFC_FCR register.
a Lock Error: the page to be programmed belongs to a locked region. A command must be previously run to
unlock the corresponding region.
Table 18-3. Flash Descriptor Definition
Symbol Word Index Description
FL_ID 0 Flash Interface Description
FL_SIZE 1 Flash size in bytes
FL_PAGE_SIZE 2 Page size in bytes
FL_NB_PLANE 3 Number of planes.
FL_PLANE[0] 4 Number of bytes in the first plane.
...
FL_PLANE[FL_NB_PLANE-1] 4 + FL_NB_PLANE - 1 Number of bytes in the last plane.
FL_NB_LOCK 4 + FL_NB_PLANE Number of lock bits. A bit is associated with a lock region. A
lock bit is used to prevent write or erase operations in the lock
region.
FL_LOCK[0] 4 + FL_NB_PLANE + 1 Number of bytes in the first lock region.
...
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By using the WP command, a page can be programmed in several steps if it has been erased before (see Figure
18-6).
Figure 18-6. Example of Partial Page Programming
The Partial Programming mode works only with 128-bit (or higher) boundaries. It cannot be used with boundaries
lower than 128 bits (8, 16 or 32-bit for example).
18.4.3.3 Erase Commands
Erase commands are allowed only on unlocked regions.
The erase sequence is:
Erase starts as soon as one of the erase commands and the FARG field are written in the Flash Command
Register.
When the programming completes, the FRDY bit in the Flash Programming Status Register (EEFC_FSR)
rises. If an interrupt has been enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC
is activated.
Two errors can be detected in the EEFC_FSR register after a programming sequence:
a Command Error: a bad keyword has been written in the EEFC_FCR register.
a Lock Error: at least one page to be erased belongs to a locked region. The erase command has been
refused, no page has been erased. A command must be run previously to unlock the corresponding region.
18.4.3.4 Lock Bit Protection
Lock bits are associated with several pages in the embedded Flash memory plane. This defines lock regions in the
embedded Flash memory plane. They prevent writing/erasing protected pages.
The lock sequence is:
The Set Lock command (SLB) and a page number to be protected are written in the Flash Command
Register.
When the locking completes, the FRDY bit in the Flash Programming Status Register (EEFC_FSR) rises. If
an interrupt has been enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC is
activated.
If the lock bit number is greater than the total number of lock bits, then the command has no effect. The
result of the SLB command can be checked running a GLB (Get Lock Bit) command.
Erase All Flash Programming of the second part of Page Y Programming of the third part of Page Y
32-bit wide 32-bit wide 32-bit wide
X words
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
...
CA FE CA FE
CA FE CA FE
CA FE CA FE
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
CA FE CA FE
CA FE CA FE
CA FE CA FE
DE CA DE CA
DE CA DE CA
DE CA DE CA
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
Step 1. Step 2. Step 3.
...
...
...
...
...
...
...
...
...
...
...
X words
X words
X words
So Page Y erased
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One error can be detected in the EEFC_FSR register after a programming sequence:
a Command Error: a bad keyword has been written in the EEFC_FCR register.
It is possible to clear lock bits previously set. Then the locked region can be erased or programmed. The unlock
sequence is:
The Clear Lock command (CLB) and a page number to be unprotected are written in the Flash Command
Register.
When the unlock completes, the FRDY bit in the Flash Programming Status Register (EEFC_FSR) rises. If
an interrupt has been enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC is
activated.
If the lock bit number is greater than the total number of lock bits, then the command has no effect.
One error can be detected in the EEFC_FSR register after a programming sequence:
a Command Error: a bad keyword has been written in the EEFC_FCR register.
The status of lock bits can be returned by the Enhanced Embedded Flash Controller (EEFC). The Get Lock Bit
status sequence is:
The Get Lock Bit command (GLB) is written in the Flash Command Register, FARG field is meaningless.
Lock bits can be read by the software application in the EEFC_FRR register. The first word read
corresponds to the 32 first lock bits, next reads providing the next 32 lock bits as long as it is meaningful.
Extra reads to the EEFC_FRR register return 0.
For example, if the third bit of the first word read in the EEFC_FRR is set, then the third lock region is locked.
One error can be detected in the EEFC_FSR register after a programming sequence:
a Command Error: a bad keyword has been written in the EEFC_FCR register.
Note: Access to the Flash in read is permitted when a set, clear or get lock bit command is performed.
18.4.3.5 GPNVM Bit
GPNVM bits do not interfere with the embedded Flash memory plane. Refer to the product definition section for
information on the GPNVM Bit Action.
The set GPNVM bit sequence is:
Start the Set GPNVM Bit command (SGPB) by writing the Flash Command Register with the SGPB
command and the number of the GPNVM bit to be set.
When the GPVNM bit is set, the bit FRDY in the Flash Programming Status Register (EEFC_FSR) rises. If
an interrupt was enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC is activated.
If the GPNVM bit number is greater than the total number of GPNVM bits, then the command has no effect.
The result of the SGPB command can be checked by running a GGPB (Get GPNVM Bit) command.
One error can be detected in the EEFC_FSR register after a programming sequence:
A Command Error: a bad keyword has been written in the EEFC_FCR register.
It is possible to clear GPNVM bits previously set. The clear GPNVM bit sequence is:
Start the Clear GPNVM Bit command (CGPB) by writing the Flash Command Register with CGPB and the
number of the GPNVM bit to be cleared.
When the clear completes, the FRDY bit in the Flash Programming Status Register (EEFC_FSR) rises. If an
interrupt has been enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC is activated.
If the GPNVM bit number is greater than the total number of GPNVM bits, then the command has no effect.
One error can be detected in the EEFC_FSR register after a programming sequence:
A Command Error: a bad keyword has been written in the EEFC_FCR register.
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The status of GPNVM bits can be returned by the Enhanced Embedded Flash Controller (EEFC). The sequence
is:
Start the Get GPNVM bit command by writing the Flash Command Register with GGPB. The FARG field is
meaningless.
GPNVM bits can be read by the software application in the EEFC_FRR register. The first word read
corresponds to the 32 first GPNVM bits, following reads provide the next 32 GPNVM bits as long as it is
meaningful. Extra reads to the EEFC_FRR register return 0.
For example, if the third bit of the first word read in the EEFC_FRR is set, then the third GPNVM bit is active.
One error can be detected in the EEFC_FSR register after a programming sequence:
a Command Error: a bad keyword has been written in the EEFC_FCR register.
Note: Access to the Flash in read is permitted when a set, clear or get GPNVM bit command is performed.
18.4.3.6 Calibration Bit
Calibration bits do not interfere with the embedded Flash memory plane.
It is impossible to modify the calibration bits.
The status of calibration bits can be returned by the Enhanced Embedded Flash Controller (EEFC). The sequence
is:
Issue the Get CALIB Bit command by writing the Flash Command Register with GCALB (see Table 18-2).
The FARG field is meaningless.
Calibration bits can be read by the software application in the EEFC_FRR register. The first word read
corresponds to the 32 first calibration bits, following reads provide the next 32 calibration bits as long as it is
meaningful. Extra reads to the EEFC_FRR register return 0.
The 4/8/12 MHz Fast RC oscillator is calibrated in production. This calibration can be read through the Get CALIB
Bit command. The table below shows the bit implementation for each frequency:
The RC calibration for 4 MHz is set to 1,000,000.
18.4.3.7 Security Bit Protection
When the security is enabled, access to the Flash, either through the JTAG/SWD interface or through the Fast
Flash Programming Interface, is forbidden. This ensures the confidentiality of the code programmed in the Flash.
The security bit is GPNVM0.
Disabling the security bit can only be achieved by asserting the ERASE pin at 1, and after a full Flash erase is
performed. When the security bit is deactivated, all accesses to the Flash are permitted.
RC Calibration Frequency EEFC_FRR Bits
8 MHz output [28 - 22]
12 MHz output [38 - 32]
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18.4.3.8 Unique Identifier
Each part is programmed with a 128-bit Unique Identifier. It can be used to generate keys for example.
To read the Unique Identifier the sequence is:
Send the Start Read unique Identifier command (STUI) by writing the Flash Command Register with the
STUI command.
When the Unique Identifier is ready to be read, the FRDY bit in the Flash Programming Status Register
(EEFC_FSR) falls.
The Unique Identifier is located in the first 128 bits of the Flash memory mapping. So, at the address
0x80000-0xFFFFF.
To stop the Unique Identifier mode, the user needs to send the Stop Read unique Identifier command (SPUI)
by writing the Flash Command Register with the SPUI command.
When the Stop read Unique Identifier command (SPUI) has been performed, the FRDY bit in the Flash
Programming Status Register (EEFC_FSR) rises. If an interrupt was enabled by setting the FRDY bit in
EEFC_FMR, the interrupt line of the NVIC is activated.
Note that during the sequence, the software can not run out of Flash (or the second plane in case of dual plane).
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18.5 Enhanced Embedded Flash Controller (EEFC) User Interface
The User Interface of the Enhanced Embedded Flash Controller (EEFC) is integrated within the System Controller with
base address 0x400E0A00 and 0x400E0C00.
Table 18-4. Register Mapping
Offset Register Name Access Reset State
0x00 EEFC Flash Mode Register EEFC_FMR Read-write 0x0
0x04 EEFC Flash Command Register EEFC_FCR Write-only –
0x08 EEFC Flash Status Register EEFC_FSR Read-only 0x00000001
0x0C EEFC Flash Result Register EEFC_FRR Read-only 0x0
0x10 Reserved – – –
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18.5.1 EEFC Flash Mode Register
Name: EEFC_FMR
Address: 0x400E0A00 (0), 0x400E0C00 (1)
Access: Read-write
Offset: 0x00
• FRDY: Ready Interrupt Enable
0: Flash Ready does not generate an interrupt.
1: Flash Ready (to accept a new command) generates an interrupt.
• FWS: Flash Wait State
This field defines the number of wait states for read and write operations:
Number of cycles for Read/Write operations = FWS+1
• FAM: Flash Access Mode
0: 128-bit access in read Mode only, to enhance access speed.
1: 64-bit access in read Mode only, to enhance power consumption.
No Flash read should be done during change of this register.
3130292827 26 25 24
–––––––FAM
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––– FWS
76543210
– –––––FRDY
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18.5.2 EEFC Flash Command Register
Name: EEFC_FCR
Address: 0x400E0A04 (0), 0x400E0C04 (1)
Access: Write-only
Offset:0x04
• FCMD: Flash Command
This field defines the flash commands. Refer to “Flash Commands” on page 295.
• FARG: Flash Command Argument
• FKEY: Flash Writing Protection Key
This field should be written with the value 0x5A to enable the command defined by the bits of the register. If the field is writ-
ten with a different value, the write is not performed and no action is started.
3130292827 26 25 24
FKEY
2322 21 20 19 1817 16
FARG
15 14 1312 11 10 9 8
FARG
76543210
FCMD
Erase command For erase all command, this field is meaningless.
Programming command FARG defines the page number to be programmed.
Lock command FARG defines the page number to be locked.
GPNVM command FARG defines the GPNVM number.
Get commands Field is meaningless.
Unique Identifier commands Field is meaningless.
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18.5.3 EEFC Flash Status Register
Name: EEFC_FSR
Address: 0x400E0A08 (0), 0x400E0C08 (1)
Access: Read-only
Offset:0x08
• FRDY: Flash Ready Status
0: The Enhanced Embedded Flash Controller (EEFC) is busy.
1: The Enhanced Embedded Flash Controller (EEFC) is ready to start a new command.
When it is set, this flags triggers an interrupt if the FRDY flag is set in the EEFC_FMR register.
This flag is automatically cleared when the Enhanced Embedded Flash Controller (EEFC) is busy.
• FCMDE: Flash Command Error Status
0: No invalid commands and no bad keywords were written in the Flash Mode Register EEFC_FMR.
1: An invalid command and/or a bad keyword was/were written in the Flash Mode Register EEFC_FMR.
This flag is automatically cleared when EEFC_FSR is read or EEFC_FCR is written.
• FLOCKE: Flash Lock Error Status
0: No programming/erase of at least one locked region has happened since the last read of EEFC_FSR.
1: Programming/erase of at least one locked region has happened since the last read of EEFC_FSR.
This flag is automatically cleared when EEFC_FSR is read or EEFC_FCR is written.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–––––FLOCKEFCMDEFRDY
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18.5.4 EEFC Flash Result Register
Name: EEFC_FRR
Address: 0x400E0A0C (0), 0x400E0C0C (1)
Access: Read-only
Offset:0x0C
• FVALUE: Flash Result Value
The result of a Flash command is returned in this register. If the size of the result is greater than 32 bits, then the next
resulting value is accessible at the next register read.
3130292827 26 25 24
FVALUE
2322 21 20 19 1817 16
FVALUE
15 14 1312 11 10 9 8
FVALUE
76543210
FVALUE
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19. Fast Flash Programming Interface (FFPI)
19.1 Description
The Fast Flash Programming Interface provides solutions for high-volume programming using a standard gang
programmer. The parallel interface is fully handshaked and the device is considered to be a standard EEPROM.
Additionally, the parallel protocol offers an optimized access to all the embedded Flash functionalities.
Although the Fast Flash Programming Mode is a dedicated mode for high volume programming, this mode is not
designed for in-situ programming.
19.2 Parallel Fast Flash Programming
19.2.1 Device Configuration
In Fast Flash Programming Mode, the device is in a specific test mode. Only a certain set of pins is significant.
Other pins must be left unconnected. The Fast Flash Programming Interface is enabled and the Fast Programming
Mode is entered when TST, PA0, PA1 are set to high, PA2 and PA3 are set to low and NRST is toggled from 0 to
1.
Figure 19-1. Parallel Programming Interface
DATA[15:0]
PGMNCMD
PGMRDY
PGMNOE
PGMNVALID
PGMM[3:0]
PGMD[15:0]
XIN
TST
NRSTB
FWUP
NCMD
RDY
NOE
NVALID
MODE[3:0]
VDDBU
0 - 50MHz (VDDCORE)
VDDBU
VDDBU
VDDIO
GND
VDDBU
GNDBU
GNDANA
GNDPLL
VDDCORE
VDDPLL
VDDANA
VDDUTMI
GNDUTMI
VDDIN
PA0VDDIO
PA1VDDIO
PA2GND
PA3GND
NRSTGND (togggle to VDDIO)
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Table 19-1. Signal Description List
Signal Name Function Type Active
Level Comments
Power
VDDIO I/O Lines Power Supply Power Apply external 3.0V-3.6V
VDDBU Backup I/O Lines Power Supply Power Apply external 3.0V-3.6V
VDDUTMI UTMI+ Interface Power Supply Power Apply external 3.0V-3.6V
VDDANA ADC Analog Power Supply Power Apply external 3.0V-3.6V
VDDIN Voltage Regulator Input Power Apply external 3.0V-3.6V
VDDCORE Core Power Supply Power Apply external 1.65V-1.95V
VDDPLL PLLs and Oscillator Power Supply Power Apply external 1.65V-1.95V
GND Ground Ground
GNDPLL Ground Ground
GNDBU Ground Ground
GNDANA Ground Ground
GNDUTMI Ground Ground
Clocks
XIN Clock Input Input 0 to 50MHz (0-VDDCORE square wave)
Test
TST Test Mode Select Input High Must be connected to VDDIO
NRSTB Asynchronous Microcontroller Reset Input High Must be connected to VDDIO
FWUP Wake-up pin Input High Must be connected to VDDIO
PIO
PGMNCMD Valid command available Input Low Pulled-up input at reset
PGMRDY 0: Device is busy
1: Device is ready for a new command Output High Pulled-up input at reset
PGMNOE Output Enable (active high) Input Low Pulled-up input at reset
PGMNVALID 0: DATA[15:0] is in input mode
1: DATA[15:0] is in output mode Output Low Pulled-up input at reset
PGMM[3:0] Specifies DATA type (See Table 19-3) Input Pulled-up input at reset
PGMD[15:0] Bi-directional data bus Input/Output Pulled-up input at reset
PA0 Input Must be connected to VDDIO at power-up
PA1 Input Must be connected to VDDIO at power-up
PA2 Input Must be connected to GND at power-up
PA3 Input Must be connected to GND at power-up
NRST Input Must be connected at start-up.
And toggle at VDDIO
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The table below shows the signal assignment of the PIO lines in FFPI mode
19.2.2 Signal Names
Depending on the MODE settings, DATA is latched in different internal registers.
When MODE is equal to CMDE, then a new command (strobed on DATA[15:0] signals) is stored in the command
register.
Table 19-2. FFPI PIO Assignment
FFPI Signal PIO Used
PGMNCMD PA0
PGMRDY PA1
PGMNOE PA2
PGMNVALID PA3
PGMM[0] PA4
PGMM[1] PA5
PGMM[2] PA6
PGMM[3] PA7
PGMD[0] PA8
PGMD[1] PA9
PGMD[2] PA10
PGMD[3] PA11
PGMD[4] PA12
PGMD[5] PA13
PGMD[6] PA14
PGMD[7] PA15
PGMD[8] PA16
PGMD[9] PA17
PGMD[10] PA18
PGMD[11] PA19
PGMD[12] PA20
PGMD[13] PA21
PGMD[14] PA22
PGMD[15] PA23
Table 19-3. Mode Coding
MODE[3:0] Symbol Data
0000 CMDE Command Register
0001 ADDR0 Address Register LSBs
0010 ADDR1 Address Register MSBs
0101 DATA Data Register
Default IDLE No register
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Note: 1. Applies to 256 kbytes Flash version (dual EEFC)
19.2.3 Entering Programming Mode
The following algorithm puts the device in Parallel Programming Mode:
Apply GND, TST, NRTSB, FWUP, PA0, PA1, PA2, PA3, NRST and the supplies as described in Table 19-1,
“Signal Description List,” on page 309.
Wait for 20 ms
Toggle NRST from 0 to 1 (GND to VDDIO).
Apply XIN clock
Wait for 20 ms
Start a read or write handshaking.
19.2.4 Programmer Handshaking
A handshake is defined for read and write operations. When the device is ready to start a new operation (RDY
signal set), the programmer starts the handshake by clearing the NCMD signal. The handshaking is achieved once
NCMD signal is high and RDY is high.
19.2.4.1 Write Handshaking
For details on the write handshaking sequence, refer to Figure 19-2 and Table 19-5.
Table 19-4. Command Bit Coding
DATA[15:0] Symbol Command Executed
0x0011 READ Read Flash
0x0012 WP Write Page Flash
0x0022 WPL Write Page and Lock Flash
0x0032 EWP Erase Page and Write Page
0x0042 EWPL Erase Page and Write Page then Lock
0x0013 EA Erase All
0x0014 SLB Set Lock Bit
0x0024 CLB Clear Lock Bit
0x0015 GLB Get Lock Bit
0x0034 SGPB Set General Purpose NVM bit
0x0044 CGPB Clear General Purpose NVM bit
0x0025 GGPB Get General Purpose NVM bit
0x0054 SSE Set Security Bit
0x0035 GSE Get Security Bit
0x001F WRAM Write Memory
0x0016 SEFC Select EEFC Controller(1)
0x001E GVE Get Version
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Figure 19-2. Parallel Programming Timing, Write Sequence
NCMD
RDY
NOE
NVALID
DATA[15:0]
MODE[3:0]
1
2
3
4
5
Table 19-5. Write Handshake
Step Programmer Action Device Action Data I/O
1 Sets MODE and DATA signals Waits for NCMD low Input
2 Clears NCMD signal Latches MODE and DATA Input
3 Waits for RDY low Clears RDY signal Input
4 Releases MODE and DATA signals Executes command and polls NCMD high Input
5 Sets NCMD signal Executes command and polls NCMD high Input
6 Waits for RDY high Sets RDY Input
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19.2.4.2 Read Handshaking
For details on the read handshaking sequence, refer to Figure 19-3 and Table 19-6.
Figure 19-3. Parallel Programming Timing, Read Sequence
19.2.5 Device Operations
Several commands on the Flash memory are available. These commands are summarized in Table 19-4 on page
311. Each command is driven by the programmer through the parallel interface running several read/write
handshaking sequences.
When a new command is executed, the previous one is automatically achieved. Thus, chaining a read command
after a write automatically flushes the load buffer in the Flash.
NCMD
RDY
NOE
NVALID
DATA[15:0]
MODE[3:0]
Adress IN Z Data OUT X IN
ADDR
1
2
3
4
5
6
7
9
810
11
12
13
Table 19-6. Read Handshake
Step Programmer Action Device Action DATA I/O
1 Sets MODE and DATA signals Waits for NCMD low Input
2 Clears NCMD signal Latch MODE and DATA Input
3 Waits for RDY low Clears RDY signal Input
4 Sets DATA signal in tristate Waits for NOE Low Input
5 Clears NOE signal Tristate
6 Waits for NVALID low Sets DATA bus in output mode and outputs
the flash contents. Output
7 Clears NVALID signal Output
8 Reads value on DATA Bus Waits for NOE high Output
9 Sets NOE signal Output
10 Waits for NVALID high Sets DATA bus in input mode X
11 Sets DATA in output mode Sets NVALID signal Input
12 Sets NCMD signal Waits for NCMD high Input
13 Waits for RDY high Sets RDY signal Input
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19.2.5.1 Flash Read Command
This command is used to read the contents of the Flash memory. The read command can start at any valid
address in the memory plane and is optimized for consecutive reads. Read handshaking can be chained; an
internal address buffer is automatically increased.
19.2.5.2 Flash Write Command
This command is used to write the Flash contents.
The Flash memory plane is organized into several pages. Data to be written are stored in a load buffer that
corresponds to a Flash memory page. The load buffer is automatically flushed to the Flash:
before access to any page other than the current one
when a new command is validated (MODE = CMDE)
The Write Page command (WP) is optimized for consecutive writes. Write handshaking can be chained; an
internal address buffer is automatically increased.
The Flash command Write Page and Lock (WPL) is equivalent to the Flash Write Command. However, the lock
bit is automatically set at the end of the Flash write operation. As a lock region is composed of several pages, the
Table 19-7. Read Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE READ
2 Write handshaking ADDR0 Memory Address LSB
3 Write handshaking ADDR1 Memory Address
4 Read handshaking DATA *Memory Address++
5 Read handshaking DATA *Memory Address++
... ... ... ...
n Write handshaking ADDR0 Memory Address LSB
n+1 Write handshaking ADDR1 Memory Address
n+2 Read handshaking DATA *Memory Address++
n+3 Read handshaking DATA *Memory Address++
... ... ... ...
Table 19-8. Write Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE WP or WPL or EWP or EWPL
2 Write handshaking ADDR0 Memory Address LSB
3 Write handshaking ADDR1 Memory Address
4 Write handshaking DATA *Memory Address++
5 Write handshaking DATA *Memory Address++
... ... ... ...
n Write handshaking ADDR0 Memory Address LSB
n+1 Write handshaking ADDR1 Memory Address
n+2 Write handshaking DATA *Memory Address++
n+3 Write handshaking DATA *Memory Address++
... ... ... ...
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programmer writes to the first pages of the lock region using Flash write commands and writes to the last page of
the lock region using a Flash write and lock command.
The Flash command Erase Page and Write (EWP) is equivalent to the Flash Write Command. However, before
programming the load buffer, the page is erased.
The Flash command Erase Page and Write the Lock (EWPL) combines EWP and WPL commands.
19.2.5.3 Flash Full Erase Command
This command is used to erase the Flash memory planes.
All lock regions must be unlocked before the Full Erase command by using the CLB command. Otherwise, the
erase command is aborted and no page is erased.
19.2.5.4 Flash Lock Commands
Lock bits can be set using WPL or EWPL commands. They can also be set by using the Set Lock command
(SLB). With this command, several lock bits can be activated. A Bit Mask is provided as argument to the
command. When bit 0 of the bit mask is set, then the first lock bit is activated.
Likewise, the Clear Lock command (CLB) is used to clear lock bits.
Lock bits can be read using Get Lock Bit command (GLB). The nth lock bit is active when the bit n of the bit mask
is set..
19.2.5.5 Flash General-purpose NVM Commands
General-purpose NVM bits (GP NVM bits) can be set using the Set GPNVM command (SGPB). This command
also activates GP NVM bits. A bit mask is provided as argument to the command. When bit 0 of the bit mask is set,
then the first GP NVM bit is activated.
Table 19-9. Full Erase Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE EA
2 Write handshaking DATA 0
Table 19-10. Set and Clear Lock Bit Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE SLB or CLB
2 Write handshaking DATA Bit Mask
Table 19-11. Get Lock Bit Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE GLB
2 Read handshaking DATA
Lock Bit Mask Status
0 = Lock bit is cleared
1 = Lock bit is set
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Likewise, the Clear GPNVM command (CGPB) is used to clear general-purpose NVM bits. All the general-
purpose NVM bits are also cleared by the EA command. The general-purpose NVM bit is deactivated when the
corresponding bit in the pattern value is set to 1.
General-purpose NVM bits can be read using the Get GPNVM Bit command (GGPB). The nth GP NVM bit is
active when bit n of the bit mask is set..
19.2.5.6 Flash Security Bit Command
A security bit can be set using the Set Security Bit command (SSE). Once the security bit is active, the Fast Flash
programming is disabled. No other command can be run. An event on the Erase pin can erase the security bit
once the contents of the Flash have been erased.
The SAM3X/A security bit is controlled by the EEFC0. To use the Set Security Bit command, the EEFC0 must be
selected using the Select EFC command.
Once the security bit is set, it is not possible to access FFPI. The only way to erase the security bit is to erase the
Flash.
In order to erase the Flash, the user must perform the following:
Power-off the chip
Power-on the chip with TST = 0
Assert Erase during a period of more than 220 ms
Power-off the chip
Then it is possible to return to FFPI mode and check that Flash is erased.
Table 19-12. Set/Clear GP NVM Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE SGPB or CGPB
2 Write handshaking DATA GP NVM bit pattern value
Table 19-13. Get GP NVM Bit Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE GGPB
2 Read handshaking DATA
GP NVM Bit Mask Status
0 = GP NVM bit is cleared
1 = GP NVM bit is set
Table 19-14. Set Security Bit Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE SSE
2 Write handshaking DATA 0
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19.2.5.7 SAM3X/A Flash Select EEFC Command
The commands WPx, EA, xLB, xFB are executed using the current EFC controller. The default EEFC controller is
EEFC0. The Select EEFC command (SEFC) allows selection of the current EEFC controller.
19.2.5.8 Memory Write Command
This command is used to perform a write access to any memory location.
The Memory Write command (WRAM) is optimized for consecutive writes. Write handshaking can be chained; an
internal address buffer is automatically increased.
19.2.5.9 Get Version Command
The Get Version (GVE) command retrieves the version of the FFPI interface.
Table 19-15. Select EFC Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE SEFC
2 Write handshaking DATA 0 = Select EEFC0
1 = Select EEFC1
Table 19-16. Write Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE WRAM
2 Write handshaking ADDR0 Memory Address LSB
3 Write handshaking ADDR1 Memory Address
4 Write handshaking DATA *Memory Address++
5 Write handshaking DATA *Memory Address++
... ... ... ...
n Write handshaking ADDR0 Memory Address LSB
n+1 Write handshaking ADDR1 Memory Address
n+2 Write handshaking DATA *Memory Address++
n+3 Write handshaking DATA *Memory Address++
... ... ... ...
Table 19-17. Get Version Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE GVE
2 Write handshaking DATA Version
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20. SAM3X/A Boot Program
20.1 Description
The SAM-BA Boot Program integrates an array of programs permitting download and/or upload into the different
memories of the product.
20.2 Flow Diagram
The Boot Program implements the algorithm illustrated in Figure 20-1.
Figure 20-1. Boot Program Algorithm Flow Diagram
The SAM-BA Boot program seeks to detect a source clock either from the embedded main oscillator with external
crystal (main oscillator enabled) or from a 12 MHz signal applied to the XIN pin (Main oscillator in Bypass mode).
If a clock is found from the two possible sources above, the boot program checks to verify that the frequency is 12
MHz (taking into account the frequency range of the 32 kHz RC oscillator). If the frequency is 12 MHz, USB
activation is allowed, else (no clock or frequency other than 12 MHz), the internal 12 MHz RC oscillator is used as
main clock and USB clock is not allowed due to frequency drift of the 12 MHz RC oscillator.
20.3 Device Initialization
The initialization sequence is the following:
1. Stack setup
2. Set up the Embedded Flash Controller
3. External Clock detection (quartz or external clock on XIN)
4. If quartz or external clock is 12.000 MHz, allow USB activation
5. Else, does not allow USB activation and use internal RC 12 MHz
6. Main oscillator frequency detection if no external clock detected
7. Switch Master Clock on Main Oscillator
8. C variable initialization
9. PLLA setup: PLLA is initialized to generate a 48 MHz clock
10. UPLL setup in case of USB activation allowed
11. Disable of the Watchdog
12. Initialization of the UART (115200 bauds, 8, N, 1)
13. Initialization of the USB Device Port (in case of USB activation allowed)
14. Wait for one of the following events
a.Check if USB device enumeration has occurred
b.Check if characters have been received in the UART
15. Jump to SAM-BA Monitor (see Section 20.4 ”SAM-BA Monitor”)
Device
SetupCharacter # received
from UART?
Run SAM-BA Monitor
USB Enumeration
Successful ?
Yes
Run SAM-BA Monitor
Yes
No
No
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20.4 SAM-BA Monitor
Once the communication interface is identified, the monitor runs in an infinite loop waiting for different commands
as shown in Table 20-1.
Mode commands:
̶Normal mode configures SAM-BA Monitor to send/receive data in binary format,
̶Terminal mode configures SAM-BA Monitor to send/receive data in ascii format.
Write commands: Write a byte (O), a halfword (H) or a word (W) to the target.
̶Address: Address in hexadecimal.
̶Value: Byte, halfword or word to write in hexadecimal.
̶Output: ‘>’.
Read commands: Read a byte (o), a halfword (h) or a word (w) from the target.
̶Address: Address in hexadecimal
̶Output: The byte, halfword or word read in hexadecimal following by ‘>’
Send a file (S): Send a file to a specified address
̶Address: Address in hexadecimal
̶Output: ‘>’.
Note: There is a time-out on this command which is reached when the prompt ‘>’ appears before the end of the command
execution.
Receive a file (R): Receive data into a file from a specified address
̶Address: Address in hexadecimal
̶NbOfBytes: Number of bytes in hexadecimal to receive
̶Output: ‘>’
Go (G): Jump to a specified address and execute the code
̶Address: Address to jump in hexadecimal
̶Output: ‘>’
Get Version (V): Return the SAM-BA boot version
̶Output: ‘>’
Table 20-1. Commands Available through the SAM-BA Boot
Command Action Argument(s) Example
Nset Normal mode No argument N#
Tset Terminal mode No argument T#
Owrite a byte Address, Value# O200001,CA#
oread a byte Address,# o200001,#
Hwrite a half word Address, Value# H200002,CAFE#
h read a half word Address,# h200002,#
W write a word Address, Value# W200000,CAFEDECA#
w read a word Address,# w200000,#
S send a file Address,# S200000,#
R receive a file Address, NbOfBytes# R200000,1234#
G go Address# G200200#
V display version No argument V#
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20.4.1 UART Serial Port
Communication is performed through the UART initialized to 115200 Baud, 8, n, 1.
The Send and Receive File commands use the Xmodem protocol to communicate. Any terminal performing this
protocol can be used to send the application file to the target. The size of the binary file to send depends on the
SRAM size embedded in the product. In all cases, the size of the binary file must be lower than the SRAM size
because the Xmodem protocol requires some SRAM memory to work. See Section 20.5 ”Hardware and Software
Constraints”.
20.4.2 Xmodem Protocol
The Xmodem protocol supported is the 128-byte length block. This protocol uses a two-character CRC-16 to
guarantee detection of a maximum bit error.
Xmodem protocol with CRC is accurate provided both sender and receiver report successful transmission. Each
block of the transfer looks like:
<SOH><blk #><255-blk #><--128 data bytes--><checksum> in which:
̶<SOH> = 01 hex
̶<blk #> = binary number, starts at 01, increments by 1, and wraps 0FFH to 00H (not to 01)
̶<255-blk #> = 1’s complement of the blk#.
̶<checksum> = 2 bytes CRC16
Figure 20-2 shows a transmission using this protocol.
Figure 20-2. Xmodem Transfer Example
20.4.3 USB Device Port
The device uses the USB communication device class (CDC) drivers to take advantage of the installed PC RS-232
software to talk over the USB. The CDC class is implemented in all releases of Windows® beginning with Windows
98SE. The CDC document, available at www.usb.org, describes a way to implement devices such as ISDN
modems and virtual COM ports.
The Vendor ID (VID) is Atmel’s vendor ID 0x03EB. The product ID (PID) is 0x6124. These references are used by
the host operating system to mount the correct driver. On Windows systems, the INF files contain the
correspondence between vendor ID and product ID.
Host Device
SOH 01 FE Data[128] CRC CRC
C
ACK
SOH 02 FD Data[128] CRC CRC
ACK
SOH 03 FC Data[100] CRC CRC
ACK
EOT
ACK
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For more details about VID/PID for End Product/Systems, please refer to the Vendor ID form available from the
USB Implementers Forum on www.usb.org.
Atmel provides an INF example to see the device as a new serial port and also provides another custom driver
used by the SAM-BA application: atm6124.sys. Refer to the application note Basic USB Application (Atmel
literature number 6123) for more details.
20.4.3.1 Enumeration Process
The USB protocol is a master/slave protocol. This is the host that starts the enumeration sending requests to the
device through the control endpoint. The device handles standard requests as defined in the USB Specification.
The device also handles some class requests defined in the CDC class.
Unhandled requests are STALLed.
20.4.3.2 Communication Endpoints
There are two communication endpoints and endpoint 0 is used for the enumeration process. Endpoint 1 is a 64-
byte Bulk OUT endpoint and endpoint 2 is a 64-byte Bulk IN endpoint. SAM-BA Boot commands are sent by the
host through endpoint 1. If required, the message is split by the host into several data payloads by the host driver.
If the command requires a response, the host can send IN transactions to pick up the response.
20.4.4 In Application Programming (IAP) Feature
The IAP feature is a function located in ROM that can be called by any software application.
When called, this function sends the desired FLASH command to the EEFC and waits for the Flash to be ready
(looping while the FRDY bit is not set in the EEFC_FSR).
Since this function is executed from ROM, this allows Flash programming (such as sector write) to be done by
code running in Flash.
The IAP function entry point is retrieved by reading the NMI vector in ROM (0x00100008).
This function takes one argument in parameter: the command to be sent to the EEFC.
This function returns the value of the EEFC_FSR.
Table 20-2. Handled Standard Requests
Request Definition
GET_DESCRIPTOR Returns the current device configuration value.
SET_ADDRESS Sets the device address for all future device access.
SET_CONFIGURATION Sets the device configuration.
GET_CONFIGURATION Returns the current device configuration value.
GET_STATUS Returns status for the specified recipient.
SET_FEATURE Set or Enable a specific feature.
CLEAR_FEATURE Clear or Disable a specific feature.
Table 20-3. Handled Class Requests
Request Definition
SET_LINE_CODING Configures DTE rate, stop bits, parity and number of character bits.
GET_LINE_CODING Requests current DTE rate, stop bits, parity and number of character bits.
SET_CONTROL_LINE_STATE RS-232 signal used to tell the DCE device the DTE device is now present.
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IAP software code example:
(unsigned int) (*IAP_Function)(unsigned long);
void main (void){
unsigned long FlashSectorNum = 200; //
unsigned long flash_cmd = 0;
unsigned long flash_status = 0;
unsigned long EFCIndex = 0; // 0:EEFC0, 1: EEFC1
/* Initialize the function pointer (retrieve function address from NMI vector)
*/
IAP_Function = ((unsigned long) (*)(unsigned long))
0x00800008;
/* Send your data to the sector here */
/* build the command to send to EEFC */
flash_cmd = (0x5A << 24) | (FlashSectorNum << 8) |
AT91C_MC_FCMD_EWP;
/* Call the IAP function with appropriate command */
flash_status = IAP_Function (EFCIndex, flash_cmd);
}
20.5 Hardware and Software Constraints
SAM-BA Boot uses the first 2048 bytes of the SRAM for variables and stacks. The remaining available size
can be used for user's code.
UART requirements:
̶12.000 MHz quartz or 12.000 MHz external clock on XIN, or
̶No quartz or external clock on XIN, or
̶Below 5.0 MHz quartz or below 5.0 MHz external clock on XIN
USB requirements:
̶12.000 MHz quartz or 12.000 MHz external clock on XIN. 12 MHz must be ±500 ppm and 1.8V Square
Wave Signal.
Table 20-4. Pins Driven during Boot Program Execution
Peripheral Pin PIO Line
UART URXD PA8
UART UTXD PA9
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21. Bus Matrix (MATRIX)
21.1 Description
Bus Matrix implements a multi-layer AHB, based on AHB-Lite protocol, that enables parallel access paths between
multiple AHB masters and slaves in a system, which increases the overall bandwidth. Bus Matrix interconnects 6
AHB Masters to 9 AHB Slaves. The normal latency to connect a master to a slave is one cycle except for the
default master of the accessed slave which is connected directly (zero cycle latency).
The Bus Matrix user interface is compliant with the ARM Advance Peripheral Bus (APB) and provides a Chip
Configuration User Interface with Registers that allow the Bus Matrix to support application specific features.
21.2 Embedded Characteristics
21.2.1 Matrix Masters
The Bus Matrix of the SAM3A/X series product manages 5 (SAM3A) or 6 (SAM3X) masters, which means that
each master can perform an access concurrently with others, to an available slave.
Each master has its own decoder, which is defined specifically for each master. In order to simplify the addressing,
all the masters have the same decoding.
21.2.2 Matrix Slaves
The Bus Matrix of the SAM3A/X series product manages 9 slaves. Each slave has its own arbiter, allowing a
different arbitration per slave.
Table 21-1. List of Bus Matrix Masters
Master 0 Cortex-M3 Instruction/Data
Master 1 Cortex-M3 System
Master 2 Peripheral DMA Controller (PDC)
Master 3 USB OTG High Speed DMA
Master 4 DMA Controller
Master 5 Ethernet MAC (AT91SAM3X)
Table 21-2. List of Bus Matrix Slaves
Slave 0 Internal SRAM0
Slave 1 Internal SRAM1
Slave 2 Internal ROM
Slave 3 Internal Flash
Slave 4 USB High Speed Dual Port RAM (DPR)
Slave 5 Nand Flash Controller RAM
Slave 6 External Bus Interface
Slave 7 High Speed Peripheral Bridge
Slave 8 Low Speed Peripheral Bridge
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21.2.3 Master to Slave Access
All the Masters can normally access all the Slaves. However, some paths do not make sense, for example
allowing access from the USB High speed DMA to the Internal Peripherals. Thus, these paths are forbidden or
simply not wired, and shown as “-” in the following table.
21.3 Memory Mapping
Bus Matrix provides one decoder for every AHB Master Interface. The decoder offers each AHB Master several
memory mappings. In fact, depending on the product, each memory area may be assigned to several slaves.
Booting at the same address while using different AHB slaves (i.e. internal ROM or internal Flash) becomes
possible.
The Bus Matrix user interface provides Master Remap Control Register (MATRIX_MRCR) that allows to perform
remap action for every master independently.
21.4 Special Bus Granting Techniques
The Bus Matrix provides some speculative bus granting techniques in order to anticipate access requests from
some masters. This mechanism allows to reduce latency at first accesses of a burst or single transfer. The bus
granting mechanism allows to set a default master for every slave.
At the end of the current access, if no other request is pending, the slave remains connected to its associated
default master. A slave can be associated with three kinds of default masters: no default master, last access
master and fixed default master.
21.4.1 No Default Master
At the end of the current access, if no other request is pending, the slave is disconnected from all masters. No
Default Master suits low power mode.
21.4.2 Last Access Master
At the end of the current access, if no other request is pending, the slave remains connected to the last master that
performed an access request.
Table 21-3. SAM3A/X series Master to Slave Access
Masters 0 1 2 3 4 5
Slaves Cortex-M3
I/D Bus Cortex-M3 S
Bus PDC USB High
Speed DMA DMA
Controller EMAC
DMA
0Internal SRAM0 - X X X X X
1Internal SRAM1 - X X X X X
2Internal ROM X - X X X X
3Internal Flash X - - ---
4USB High Speed Dual Port RAM - X - - X -
5Nand Flash Controller RAM - X X X X X
6External Bus Interface - X X X X X
7High Speed Peripheral Bridge - X X - X -
8Low Speed Peripheral Bridge - X - - X -
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21.4.3 Fixed Default Master
At the end of the current access, if no other request is pending, the slave connects to its fixed default master.
Unlike last access master, the fixed master doesn’t change unless the user modifies it by a software action (field
FIXED_DEFMSTR of the related MATRIX_SCFG).
To change from one kind of default master to another, the Bus Matrix user interface provides the Slave
Configuration Registers, one for each slave, that allow to set a default master for each slave. The Slave
Configuration Register contains two fields:
DEFMSTR_TYPE and FIXED_DEFMSTR. The 2-bit DEFMSTR_TYPE field allows to choose the default master
type (no default, last access master, fixed default master) whereas the 4-bit FIXED_DEFMSTR field allows to
choose a fixed default master provided that DEFMSTR_TYPE is set to fixed default master. Please refer to the
Bus Matrix user interface description.
21.5 Arbitration
The Bus Matrix provides an arbitration mechanism that allows to reduce latency when conflict cases occur,
basically when two or more masters try to access the same slave at the same time. One arbiter per AHB slave is
provided, allowing to arbitrate each slave differently.
The Bus Matrix provides the user the possibility to choose between 2 arbitration types for each slave:
1. Round-Robin Arbitration (the default)
2. Fixed Priority Arbitration
This choice is given through the ARBT field of the Slave Configuration Registers (MATRIX_SCFG).
Each algorithm may be complemented by selecting a default master configuration for each slave.
When re-arbitration has to be done, it is realized only under specific conditions as detailed in the following
paragraph.
21.5.1 Arbitration Rules
Each arbiter has the ability to arbitrate between two or more different master’s requests. In order to avoid burst
breaking and also to provide the maximum throughput for slave interfaces, arbitration may only take place during
the following cycles:
1. Idle Cycles: when a slave is not connected to any master or is connected to a master which is not cur-
rently accessing it.
2. Single Cycles: when a slave is currently doing a single access.
3. End of Burst Cycles: when the current cycle is the last cycle of a burst transfer. For defined length burst,
predicted end of burst matches the size of the transfer but is managed differently for undefined length burst
(See Section 21.5.1.1 “Undefined Length Burst Arbitration” on page 325“).
4. Slot Cycle Limit: when the slot cycle counter has reached the limit value indicating that the current master
access is too long and must be broken (See Section 21.5.1.2 “Slot Cycle Limit Arbitration” on page 326).
21.5.1.1 Undefined Length Burst Arbitration
In order to avoid too long slave handling during undefined length bursts (INCR), the Bus Matrix provides specific
logic in order to re-arbitrate before the end of the INCR transfer.
A predicted end of burst is used as for defined length burst transfer, which is selected between the following:
1. Infinite: no predicted end of burst is generated and therefore INCR burst transfer will never be broken.
2. Four beat bursts: predicted end of burst is generated at the end of each four beat boundary inside INCR
transfer.
3. Eight beat bursts: predicted end of burst is generated at the end of each eight beat boundary inside INCR
transfer.
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4. Sixteen beat bursts: predicted end of burst is generated at the end of each sixteen beat boundary inside
INCR transfer.
This selection can be done through the ULBT field of the Master Configuration Registers (MATRIX_MCFG).
21.5.1.2 Slot Cycle Limit Arbitration
The Bus Matrix contains specific logic to break too long accesses such as very long bursts on a very slow slave
(e.g. an external low speed memory). At the beginning of the burst access, a counter is loaded with the value
previously written in the SLOT_CYCLE field of the related Slave Configuration Register (MATRIX_SCFG) and
decreased at each clock cycle. When the counter reaches zero, the arbiter has the ability to re-arbitrate at the end
of the current byte, half word or word transfer.
21.5.2 Round-Robin Arbitration
This algorithm allows the Bus Matrix arbiters to dispatch the requests from different masters to the same slave in a
round-robin manner. If two or more master’s requests arise at the same time, the master with the lowest number is
first serviced then the others are serviced in a round-robin manner.
There are three round-robin algorithm implemented:
Round-Robin arbitration without default master
Round-Robin arbitration with last access master
Round-Robin arbitration with fixed default master
21.5.2.1 Round-Robin arbitration without default master
This is the main algorithm used by Bus Matrix arbiters. It allows the Bus Matrix to dispatch requests from different
masters to the same slave in a pure round-robin manner. At the end of the current access, if no other request is
pending, the slave is disconnected from all masters. This configuration incurs one latency cycle for the first access
of a burst. Arbitration without default master can be used for masters that perform significant bursts.
21.5.2.2 Round-Robin arbitration with last access master
This is a biased round-robin algorithm used by Bus Matrix arbiters. It allows the Bus Matrix to remove the one
latency cycle for the last master that accessed the slave. In fact, at the end of the current transfer, if no other
master request is pending, the slave remains connected to the last master that performs the access. Other non
privileged masters will still get one latency cycle if they want to access the same slave. This technique can be used
for masters that mainly perform single accesses.
21.5.2.3 Round-Robin arbitration with fixed default master
This is another biased round-robin algorithm, it allows the Bus Matrix arbiters to remove the one latency cycle for
the fixed default master per slave. At the end of the current access, the slave remains connected to its fixed default
master. Every request attempted by this fixed default master will not cause any latency whereas other non
privileged masters will still get one latency cycle. This technique can be used for masters that mainly perform
single accesses.
21.5.3 Fixed Priority Arbitration
This algorithm allows the Bus Matrix arbiters to dispatch the requests from different masters to the same slave by
using the fixed priority defined by the user. If two or more master’s requests are active at the same time, the
master with the highest priority number is serviced first. If two or more master’s requests with the same priority are
active at the same time, the master with the highest number is serviced first.
For each slave, the priority of each master may be defined through the Priority Registers for Slaves
(MATRIX_PRAS and MATRIX_PRBS).
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21.6 System I/O Configuration
The System I/O Configuration register (CCFG_SYSIO) allows to configure I/O lines in System I/O mode (such as
ERASE) or as general purpose I/O lines. Enabling or disabling the corresponding I/O lines in peripheral mode, or
in PIO mode (PIO_PER or PIO_PDR registers) in the PIO controller, has no effect. However, the direction (input or
output), pull-up and other mode control, is still managed by the PIO controller.
21.7 Write Protect Registers
To prevent any single software error that may corrupt MATRIX behavior, the entire MATRIX address space from
address offset 0x000 to 0x1FC can be write-protected by setting the WPEN bit in the MATRIX Write Protect Mode
Register (MATRIX_WPMR).
If a write access to anywhere in the MATRIX address space from address offset 0x000 to 0x1FC is detected, then
the WPVS flag in the MATRIX Write Protect Status Register (MATRIX_WPSR) is set and the WPVSRC field
indicates in which register the write access has been attempted.
The WPVS flag is reset by writing the MATRIX Write Protect Mode Register (MATRIX_WPMR) with the
appropriate access key, WPKEY.
The protected registers are:
“Bus Matrix Master Configuration Registers”
“Bus Matrix Slave Configuration Registers”
“Bus Matrix Priority Registers For Slaves”
“Bus Matrix Master Remap Control Register”
“System I/O Configuration Register”
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21.8 Bus Matrix (MATRIX) User Interface
Table 21-4. Register Mapping
Offset Register Name Access Reset
0x0000 Master Configuration Register 0 MATRIX_MCFG0 Read-write 0x00000000
0x0004 Master Configuration Register 1 MATRIX_MCFG1 Read-write 0x00000000
0x0008 Master Configuration Register 2 MATRIX_MCFG2 Read-write 0x00000000
0x000C Master Configuration Register 3 MATRIX_MCFG3 Read-write 0x00000000
0x0010 Master Configuration Register 4 MATRIX_MCFG4 Read-write 0x00000000
0x0014 Master Configuration Register 5 MATRIX_MCFG5 Read-write 0x00000000
0x0018 - 0x003C Reserved – – –
0x0040 Slave Configuration Register 0 MATRIX_SCFG0 Read-write 0x00010010
0x0044 Slave Configuration Register 1 MATRIX_SCFG1 Read-write 0x00050010
0x0048 Slave Configuration Register 2 MATRIX_SCFG2 Read-write 0x00000010
0x004C Slave Configuration Register 3 MATRIX_SCFG3 Read-write 0x00000010
0x0050 Slave Configuration Register 4 MATRIX_SCFG4 Read-write 0x00000010
0x0054 Slave Configuration Register 5 MATRIX_SCFG5 Read-write 0x00000010
0x0058 Slave Configuration Register 6 MATRIX_SCFG6 Read-write 0x00000010
0x005C Slave Configuration Register 7 MATRIX_SCFG7 Read-write 0x00000010
0x0060 Slave Configuration Register 8 MATRIX_SCFG8 Read-write 0x00000010
0x0064 - 0x007C Reserved – – –
0x0080 Priority Register A for Slave 0 MATRIX_PRAS0 Read-write 0x00000000
0x0084 Reserved – – –
0x0088 Priority Register A for Slave 1 MATRIX_PRAS1 Read-write 0x00000000
0x008C Reserved – – –
0x0090 Priority Register A for Slave 2 MATRIX_PRAS2 Read-write 0x00000000
0x0094 Reserved – – –
0x0098 Priority Register A for Slave 3 MATRIX_PRAS3 Read-write 0x00000000
0x009C Reserved – – –
0x00A0 Priority Register A for Slave 4 MATRIX_PRAS4 Read-write 0x00000000
0x00A4 Reserved – – –
0x00A8 Priority Register A for Slave 5 MATRIX_PRAS5 Read-write 0x00000000
0x00AC Reserved – – –
0x00B0 Priority Register A for Slave 6 MATRIX_PRAS6 Read-write 0x00000000
0x00B4 Reserved – – –
0x00B8 Priority Register A for Slave 7 MATRIX_PRAS7 Read-write 0x00000000
0x00BC Reserved – – –
0x00C0 Priority Register A for Slave 8 MATRIX_PRAS8 Read-write 0x00000000
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0x00C4- 0x00FC Reserved – – –
0x0100 Master Remap Control Register MATRIX_MRCR Read-write 0x00000000
0x0104 - 0x0110 Reserved – – –
0x0114 System I/O Configuration register CCFG_SYSIO Read/Write 0x00000000
0x0118 - 0x01E0 Reserved – – –
0x1E4 Write Protect Mode Register MATRIX_WPMR Read-write 0x0
0x1E8 Write Protect Status Register MATRIX_WPSR Read-only 0x0
0x01EC-0x01FC Reserved – – –
Table 21-4. Register Mapping (Continued)
Offset Register Name Access Reset
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21.8.1 Bus Matrix Master Configuration Registers
Name: MATRIX_MCFG0..MATRIX_MCFG5
Address: 0x400E0400
Access: Read-write
This register can only be written if the WPEN bit is cleared in the “Write Protect Mode Register” .
• ULBT: Undefined Length Burst Type
0: Infinite Length Burst
No predicted end of burst is generated and therefore INCR bursts coming from this master cannot be broken.
1: Single Access
The undefined length burst is treated as a succession of single access allowing rearbitration at each beat of the INCR
burst.
2: Four Beat Burst
The undefined length burst is split into 4 beats burst allowing rearbitration at each 4 beats burst end.
3: Eight Beat Burst
The undefined length burst is split into 8 beats burst allowing rearbitration at each 8 beats burst end.
4: Sixteen Beat Burst
The undefined length burst is split into 16 beats burst allowing rearbitration at each 16 beats burst end.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––– ULBT
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21.8.2 Bus Matrix Slave Configuration Registers
Name: MATRIX_SCFG0..MATRIX_SCFG8
Address: 0x400E0440
Access: Read-write
This register can only be written if the WPEN bit is cleared in the “Write Protect Mode Register” .
• SLOT_CYCLE: Maximum Number of Allowed Cycles for a Burst
When the SLOT_CYCLE limit is reach for a burst it may be broken by another master trying to access this slave.
This limit has been placed to avoid locking very slow slave by when very long burst are used.
This limit should not be very small though. Unreasonable small value will break every burst and Bus Matrix will spend its
time to arbitrate without performing any data transfer. 16 cycles is a reasonable value for SLOT_CYCLE.
• DEFMSTR_TYPE: Default Master Type
0: No Default Master
At the end of current slave access, if no other master request is pending, the slave is disconnected from all masters.
This results in having a one cycle latency for the first access of a burst transfer or for a single access.
1: Last Default Master
At the end of current slave access, if no other master request is pending, the slave stay connected with the last master
having accessed it.
This results in not having the one cycle latency when the last master re-tries access on the slave again.
2: Fixed Default Master
At the end of the current slave access, if no other master request is pending, the slave connects to the fixed master which
number has been written in the FIXED_DEFMSTR field.
This results in not having the one cycle latency when the fixed master re-tries access on the slave again.
• FIXED_DEFMSTR: Fixed Default Master
This is the number of the Default Master for this slave. Only used if DEFMSTR_TYPE is 2. Specifying the number of a
master which is not connected to the selected slave is equivalent to setting DEFMSTR_TYPE to 0.
31 30 29 28 27 26 25 24
–––––– ARBT
23 22 21 20 19 18 17 16
– – – FIXED_DEFMSTR DEFMSTR_TYPE
15 14 13 12 11 10 9 8
––––––––
76543210
SLOT_CYCLE
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• ARBT: Arbitration Type
0: Round-Robin Arbitration
1: Fixed Priority Arbitration
2: Reserved
3: Reserved
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21.8.3 Bus Matrix Priority Registers For Slaves
Name: MATRIX_PRAS0..MATRIX_PRAS8
Address: 0x400E0480 [0], 0x400E0488 [1], 0x400E0490 [2], 0x400E0498 [3], 0x400E04A0 [4], 0x400E04A8 [5],
0x400E04B0 [6], 0x400E04B8 [7], 0x400E04C0 [8]
Access: Read-write
This register can only be written if the WPEN bit is cleared in the “Write Protect Mode Register” .
• MxPR: Master x Priority
Fixed priority of Master x for accessing the selected slave.The higher the number, the higher the priority.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–– M5PR –– M4PR
15 14 13 12 11 10 9 8
–– M3PR –– M2PR
76543210
–– M1PR –– M0PR
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21.8.4 Bus Matrix Master Remap Control Register
Name: MATRIX_MRCR
Address: 0x400E0500
Access: Read-write
Reset: 0x0000_0000
This register can only be written if the WPEN bit is cleared in the “Write Protect Mode Register” .
• RCBx: Remap Command Bit for AHB Master x
0: Disable remapped address decoding for the selected Master
1: Enable remapped address decoding for the selected Master
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– RCB5 RCB4 RCB4 RCB3 RCB2 RCB1 RCB0
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21.8.5 System I/O Configuration Register
Name: CCFG_SYSIO
Address: 0x400E0514
Access: Read-write
Reset: 0x0000_1000
• SYSIO12: PC0 or ERASE Assignment
1: ERASE function selected (Default at reset).
0: PC0 function selected.
When ERASE function is selected, pull down of PC0 is enabled, and pull up of PC0 is disabled.
When PC0 function is selected, pull down of PC0 is disabled and pull up of PC0 is configurable through PIO block.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––SYSIO12––––
76543210
––––––––
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21.8.6 Write Protect Mode Register
Name: MATRIX_WPMR
Address: 0x400E05E4
Access: Read-write
For more details on MATRIX_WPMR, refer to Section 21.7 “Write Protect Registers” on page 327.
• WPEN: Write Protect ENable
0: Disables the Write Protect if WPKEY corresponds to 0x4D4154 (“MAT” in ASCII).
1: Enables the Write Protect if WPKEY corresponds to 0x4D4154 (“MAT” in ASCII).
Protects the entire MATRIX address space from address offset 0x000 to 0x1FC.
• WPKEY: Write Protect KEY (Write-only)
Should be written at value 0x4D4154 (“MAT” in ASCII). Writing any other value in this field aborts the write operation of the
WPEN bit. Always reads as 0.
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
–––––––WPEN
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21.8.7 Write Protect Status Register
Name: MATRIX_WPSR
Address: 0x400E05E8
Access: Read-only
For more details on MATRIX_WPSR, refer to Section 21.7 “Write Protect Registers” on page 327.
• WPVS: Write Protect Violation Status
0: No Write Protect Violation has occurred since the last write of MATRIX_WPMR.
1: At least one Write Protect Violation has occurred since the last write of MATRIX_WPMR.
• WPVSRC: Write Protect Violation Source
Should be written at value 0x4D4154 (“MAT” in ASCII). Writing any other value in this field aborts the write operation of the
WPEN bit. Always reads as 0.
The protected registers are:
•“Bus Matrix Master Configuration Registers”
•“Bus Matrix Slave Configuration Registers”
•“Bus Matrix Priority Registers For Slaves”
•“Bus Matrix Master Remap Control Register”
•“System I/O Configuration Register”
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
WPVSRC
15 14 13 12 11 10 9 8
WPVSRC
76543210
–––––––WPVS
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22. AHB DMA Controller (DMAC)
22.1 Description
The DMA Controller (DMAC) is an AHB-central DMA controller core that transfers data from a source peripheral to
a destination peripheral over one or more AMBA buses. One channel is required for each source/destination pair.
In the most basic configuration, the DMAC has one master interface and one channel. The master interface reads
the data from a source and writes it to a destination. Two AMBA transfers are required for each DMAC data
transfer. This is also known as a dual-access transfer.
The DMAC is programmed via the APB interface.
The DMAC embeds 6 channels:
22.2 Embedded Characteristics
Programmable Arbitration Policy, Modified Round Robin and Fixed Priority are Available
Acting as one Matrix Master
Embeds 4 (SAM3A and 100-pin SAM3X) or 6 (144-pin SAM3X and 217-pin SAM3X8H(1)) channels
Note: 1.This device is not commercially available. Mounted only on the SAM3X-EK evaluation kit.
Linked List support with Status Write Back operation at End of Transfer
Word, HalfWord, Byte transfer support.
Handles high speed transfer of SPI0-1, SSC and HSMCI (peripheral to memory, memory to peripheral)
Memory to memory transfer
DMAC Channel Number FIFO Size
08
18
28
332
48
532
Table 22-1. DMA Channels
DMA Channel Size
SAM3A
100-pin SAM3X
144-pin SAM3X
217-pin SAM3X8H(1)
8 bytes FIFO for Channel Buffering 3
(Channels 0, 1 and 2)
4
(Channels 0, 1, 2 and 4)
32 bytes FIFO for Channel Buffering 1
(Channel 3)
2
(Channels 3 and 5)
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The DMA controller can handle the transfer between peripherals and memory and so receives the triggers from the
peripherals below. The hardware interface numbers are also given in Table 22-2.
Table 22-2. DMA Controller
Instance Name Channel T/R DMA Channel HW
Interface Number
HSMCI Transmit/Receive 0
SPI0 Transmit 1
SPI0 Receive 2
SSC Transmit 3
SSC Receive 4
SPI1 Transmit 5
SPI1 Receive 6
TWI0 Transmit 7
TWI0 Receive 8
-- -
-- -
USART0 Transmit 11
USART0 Receive 12
USART1 Transmit 13
USART1 Receive 14
PWM Transmit 15
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22.3 Block Diagram
Figure 22-1. DMA Controller (DMAC) Block Diagram
DMA Destination
DMA Channel 0
DMA Destination
Control State Machine
Destination Pointer
Management
DMA Source
Control State Machine
Source Pointer
Management
DMA FIFO Controller
DMA FIFO
Up to 64 bytes
DMA Channel 0
Read data path
from source
DMA Channel 0
Write data path
to destination
DMA Channel 1
DMA Channel 2
DMA Channel n
External
Triggers
Soft
Triggers
DMA
REQ/ACK
Interface
Trigger Manager
DMA Interrupt
Controller
Status
Registers
Configuration
Registers
Atmel APB rev2 Interface
DMA AHB Lite Master Interface 0
DMA Global Control
and Data MuxDMA Global
Request Arbiter
DMA Source
Requests Pool
DMA Read
Datapath Bundles
DMA
Atmel
APB
Interface
DMA Interrupt
DMA
Hardware
Handshaking
Interface
AMBA AHB Layer 0
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22.4 Functional Description
22.4.1 Basic Definitions
Source peripheral: Device on an AMBA layer from where the DMAC reads data, which is then stored in the
channel FIFO. The source peripheral teams up with a destination peripheral to form a channel.
Destination peripheral: Device to which the DMAC writes the stored data from the FIFO (previously read from the
source peripheral).
Memory: Source or destination that is always “ready” for a DMAC transfer and does not require a handshaking
interface to interact with the DMAC.
Programmable Arbitration Policy: Modified Round Robin and Fixed Priority are available by means of the
ARB_CFG bit in the Global Configuration Register (DMAC_GCFG). The fixed priority is linked to the channel
number. The highest DMAC channel number has the highest priority.
Channel: Read/write datapath between a source peripheral on one configured AMBA layer and a destination
peripheral on the same or different AMBA layer that occurs through the channel FIFO. If the source peripheral is
not memory, then a source handshaking interface is assigned to the channel. If the destination peripheral is not
memory, then a destination handshaking interface is assigned to the channel. Source and destination
handshaking interfaces can be assigned dynamically by programming the channel registers.
Master interface: DMAC is a master on the AHB bus reading data from the source and writing it to the destination
over the AHB bus.
Slave interface: The APB interface over which the DMAC is programmed. The slave interface in practice could be
on the same layer as any of the master interfaces or on a separate layer.
Handshaking interface: A set of signal registers that conform to a protocol and handshake between the DMAC
and source or destination peripheral to control the transfer of a single or chunk transfer between them. This
interface is used to request, acknowledge, and control a DMAC transaction. A channel can receive a request
through one of two types of handshaking interface: hardware or software.
Hardware handshaking interface: Uses hardware signals to control the transfer of a single or chunk transfer
between the DMAC and the source or destination peripheral.
Software handshaking interface: Uses software registers to control the transfer of a single or chunk transfer
between the DMAC and the source or destination peripheral. No special DMAC handshaking signals are needed
on the I/O of the peripheral. This mode is useful for interfacing an existing peripheral to the DMAC without
modifying it.
Flow controller: The device (either the DMAC or source/destination peripheral) that determines the length of and
terminates a DMAC buffer transfer. If the length of a buffer is known before enabling the channel, then the DMAC
should be programmed as the flow controller. If the length of a buffer is not known prior to enabling the channel,
the source or destination peripheral needs to terminate a buffer transfer. In this mode, the peripheral is the flow
controller.
Transfer hierarchy: Figure 22-2 on page 342 illustrates the hierarchy between DMAC transfers, buffer transfers,
chunk or single, and AMBA transfers (single or burst) for non-memory peripherals. Figure 22-3 on page 342 shows
the transfer hierarchy for memory.
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Figure 22-2. DMAC Transfer Hierarchy for Non-Memory Peripheral
Figure 22-3. DMAC Transfer Hierarchy for Memory
Buffer: A buffer of DMAC data. The amount of data (length) is determined by the flow controller. For transfers
between the DMAC and memory, a buffer is broken directly into a sequence of AMBA bursts and AMBA single
transfers.
For transfers between the DMAC and a non-memory peripheral, a buffer is broken into a sequence of DMAC
transactions (single and chunks). These are in turn broken into a sequence of AMBA transfers.
Transaction: A basic unit of a DMAC transfer as determined by either the hardware or software handshaking
interface. A transaction is only relevant for transfers between the DMAC and a source or destination peripheral if
the source or destination peripheral is a non-memory device. There are two types of transactions: single transfer
and chunk transfer.
̶Single transfer: The length of a single transaction is always 1 and is converted to a single AMBA
access.
̶Chunk transfer: The length of a chunk is programmed into the DMAC. The chunk is then converted
into a sequence of AHB access.DMAC executes each AMBA burst transfer by performing incremental
bursts that are no longer than 16 beats.
DMAC transfer: Software controls the number of buffers in a DMAC transfer. Once the DMAC transfer has
completed, then hardware within the DMAC disables the channel and can generate an interrupt to signal the
completion of the DMAC transfer. You can then re-program the channel for a new DMAC transfer.
DMAC Transfer DMA Transfer
Level
Buffer Buffer Buffer Buffer Transfer
Level
Chunk
Transfer Chunk
Transfer
Chunk
Transfer Single
Transfer
DMA Transaction
Level
Burst
Transfer
AMBA Burst
Transfer
AMBA Burst
Transfer
AMBA Single
Transfer
AMBA AMBA Transfer
Level
Single
Transfer
AMBA
DMAC Transfer DMA Transfer
Level
Buffer Buffer Buffer Buffer Transfer
Level
Burst
Transfer
AMBA Burst
Transfer
AMBA Burst
Transfer
AMBA Single
Transfer
AMBA AMBA Transfer
Level
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Single-buffer DMAC transfer: Consists of a single buffer.
Multi-buffer DMAC transfer: A DMAC transfer may consist of multiple DMAC buffers. Multi-buffer DMAC
transfers are supported through buffer chaining (linked list pointers), auto-reloading of channel registers, and
contiguous buffers. The source and destination can independently select which method to use.
̶Linked lists (buffer chaining) – A descriptor pointer (DSCR) points to the location in system memory
where the next linked list item (LLI) exists. The LLI is a set of registers that describe the next buffer
(buffer descriptor) and a descriptor pointer register. The DMAC fetches the LLI at the beginning of
every buffer when buffer chaining is enabled.
̶Contiguous buffers – Where the address of the next buffer is selected to be a continuation from the
end of the previous buffer.
Channel locking: Software can program a channel to keep the AHB master interface by locking the arbitration for
the master bus interface for the duration of a DMAC transfer, buffer, or chunk.
Bus locking: Software can program a channel to maintain control of the AMBA bus by asserting hmastlock for the
duration of a DMAC transfer, buffer, or transaction (single or chunk). Channel locking is asserted for the duration of
bus locking at a minimum.
22.4.2 Memory Peripherals
Figure 22-3 on page 342 shows the DMAC transfer hierarchy of the DMAC for a memory peripheral. There is no
handshaking interface with the DMAC, and therefore the memory peripheral can never be a flow controller. Once
the channel is enabled, the transfer proceeds immediately without waiting for a transaction request. The alternative
to not having a transaction-level handshaking interface is to allow the DMAC to attempt AMBA transfers to the
peripheral once the channel is enabled. If the peripheral slave cannot accept these AMBA transfers, it inserts wait
states onto the bus until it is ready; it is not recommended that more than 16 wait states be inserted onto the bus.
By using the handshaking interface, the peripheral can signal to the DMAC that it is ready to transmit/receive data,
and then the DMAC can access the peripheral without the peripheral inserting wait states onto the bus.
22.4.3 Handshaking Interface
Handshaking interfaces are used at the transaction level to control the flow of single or chunk transfers. The
operation of the handshaking interface is different and depends on whether the peripheral or the DMAC is the flow
controller.
The peripheral uses the handshaking interface to indicate to the DMAC that it is ready to transfer/accept data over
the AMBA bus. A non-memory peripheral can request a DMAC transfer through the DMAC using one of two
handshaking interfaces:
Hardware handshaking
Software handshaking
Software selects between the hardware or software handshaking interface on a per-channel basis. Software
handshaking is accomplished through memory-mapped registers, while hardware handshaking is accomplished
using a dedicated handshaking interface.
22.4.3.1 Software Handshaking
When the slave peripheral requires the DMAC to perform a DMAC transaction, it communicates this request by
sending an interrupt to the CPU or interrupt controller.
The interrupt service routine then uses the software registers to initiate and control a DMAC transaction. These
software registers are used to implement the software handshaking interface.
The SRC_H2SEL/DST_H2SEL bit in the DMAC_CFGx channel configuration register must be set to zero to
enable software handshaking.
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When the peripheral is not the flow controller, then the last transaction register DMAC_LAST is not used, and the
values in these registers are ignored.
Chunk Transactions
Writing a 1 to the DMAC_CREQ[2x] register starts a source chunk transaction request, where x is the channel
number. Writing a 1 to the DMAC_CREQ[2x+1] register starts a destination chunk transfer request, where x is the
channel number.
Upon completion of the chunk transaction, the hardware clears the DMAC_CREQ[2x] or DMAC_CREQ[2x+1].
Single Transactions
Writing a 1 to the DMAC_SREQ[2x] register starts a source single transaction request, where x is the channel
number. Writing a 1 to the DMAC_SREQ[2x+1] register starts a destination single transfer request, where x is the
channel number.
Upon completion of the chunk transaction, the hardware clears the DMAC_SREQ[x] or DMAC_SREQ[2x+1].
The software can poll the relevant channel bit in the DMAC_CREQ[2x]/DMAC_CREQ[2x+1] and
DMAC_SREQ[x]/DMAC_SREQ[2x+1] registers. When both are 0, then either the requested chunk or single
transaction has completed.
22.4.4 DMAC Transfer Types
A DMAC transfer may consist of single or multi-buffer transfers. On successive buffers of a multi-buffer transfer,
the DMAC_SADDRx/DMAC_DADDRx registers in the DMAC are reprogrammed using either of the following
methods:
Buffer chaining using linked lists
Contiguous address between buffers
On successive buffers of a multi-buffer transfer, the DMAC_CTRLAx and DMAC_CTRLBx registers in the DMAC
are re-programmed using either of the following methods:
Buffer chaining using linked lists
When buffer chaining using linked lists is the multi-buffer method of choice, and on successive buffers, the
DMAC_DSCRx register in the DMAC is re-programmed using the following method:
Buffer chaining using linked lists
A buffer descriptor (LLI) consists of following registers, DMAC_SADDRx, DMAC_DADDRx, DMAC_DSCRx,
DMAC_CTRLAx, DMAC_CTRLBx.These registers, along with the DMAC_CFGx register, are used by the DMAC
to set up and describe the buffer transfer.
22.4.4.1 Multi-buffer Transfers
Buffer Chaining Using Linked Lists
In this case, the DMAC re-programs the channel registers prior to the start of each buffer by fetching the buffer
descriptor for that buffer from system memory. This is known as an LLI update.
DMAC buffer chaining is supported by using a Descriptor Pointer register (DMAC_DSCRx) that stores the address
in memory of the next buffer descriptor. Each buffer descriptor contains the corresponding buffer descriptor
(DMAC_SADDRx, DMAC_DADDRx, DMAC_DSCRx, DMAC_CTRLAx DMAC_CTRLBx).
To set up buffer chaining, a sequence of linked lists must be programmed in memory.
The DMAC_SADDRx, DMAC_DADDRx, DMAC_DSCRx, DMAC_CTRLAx and DMAC_CTRLBx registers are
fetched from system memory on an LLI update. The updated content of the DMAC_CTRLAx register is written
back to memory on buffer completion. Figure 22-4 on page 345 shows how to use chained linked lists in memory
to define multi-buffer transfers using buffer chaining.
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The Linked List multi-buffer transfer is initiated by programming DMAC_DSCRx with DSCRx(0) (LLI(0) base
address) different from zero. Other fields and registers are ignored and overwritten when the descriptor is retrieved
from memory.
The last transfer descriptor must be written to memory with its next descriptor address set to 0.
Figure 22-4. Multi Buffer Transfer Using Linked List
22.4.4.2 Programming DMAC for Multiple Buffer Transfers
Notes: 1. USR means that the register field is manually programmed by the user.
2. CONT means that address are contiguous.
3. Channel stalled is true if the relevant BTC interrupt is not masked.
4. LLI means that the register field is updated with the content of the linked list item.
Contiguous Address Between Buffers
In this case, the address between successive buffers is selected to be a continuation from the end of the previous
buffer. Enabling the source or destination address to be contiguous between buffers is a function of
DMAC_CTRLAx.SRC_DSCR and DMAC_CTRLAx.DST_DSCR registers.
Suspension of Transfers Between Buffers
At the end of every buffer transfer, an end of buffer interrupt is asserted if:
the channel buffer interrupt is unmasked, DMAC_EBCIMR.BTCx = ‘1’, where x is the channel number.
Note: The Buffer Transfer Completed Interrupt is generated at the completion of the buffer transfer to the destination.
At the end of a chain of multiple buffers, an end of linked list interrupt is asserted if:
the channel end of the Chained Buffer Transfer Completed Interrupt is unmasked, DMAC_EBCIMR.CBTCx
= ‘1’, when n is the channel number.
Table 22-4. Multiple Buffers Transfer Management
Transfer Type SRC_DSCR DST_DSCR BTSIZE DSCR SADDR DADDR Other Fields
1) Single Buffer or Last buffer of a multiple buffer transfer – – USR 0 USR USR USR
2) Multi Buffer transfer with contiguous DADDR 0 1 LLI USR LLI CONT LLI
3) Multi Buffer transfer with contiguous SADDR 1 0 LLI USR CONT LLI LLI
4) Multi Buffer transfer with LLI support 0 0 LLI USR LLI LLI LLI
System Memory
SADDRx= DSCRx(0) + 0x0
DADDRx= DSCRx(0) + 0x4
CTRLAx= DSCRx(0) + 0x8
CTRLBx= DSCRx(0) + 0xC
DSCRx(1)= DSCRx(0) + 0x10
SADDRx= DSCRx(1) + 0x0
DADDRx= DSCRx(1) + 0x4
CTRLBx= DSCRx(1) + 0x8
CTRLBx= DSCRx(1) + 0xC
DSCRx(2)= DSCRx(1) + 0x10
DSCRx(0) DSCRx(2)
(points to 0 if
LLI(1) is the last
transfer descriptor
DSCRx(1)
LLI(0) LLI(1)
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22.4.4.3 Ending Multi-buffer Transfers
All multi-buffer transfers must end as shown in Row 1 of Table 22-4 on page 345. At the end of every buffer
transfer, the DMAC samples the row number, and if the DMAC is in Row 1 state, then the previous buffer
transferred was the last buffer and the DMAC transfer is terminated.
For rows 2, 3, 4, 5, and 6 (DMAC_CRTLBx.AUTO cleared), the user must set up the last buffer descriptor in
memory so that LLI.DMAC_CTRLBx.SRC_DSCR is set to 0.
22.4.5 Programming a Channel
Four registers, the DMAC_DSCRx, the DMAC_CTRLAx, the DMAC_CTRLBx and DMAC_CFGx, need to be
programmed to set up whether single or multi-buffer transfers take place, and which type of multi-buffer transfer is
used. The different transfer types are shown in Table 22-4 on page 345.
The “BTSIZE, SADDR and DADDR” columns indicate where the values of DMAC_SARx, DMAC_DARx,
DMAC_CTLx, and DMAC_LLPx are obtained for the next buffer transfer when multi-buffer DMAC transfers are
enabled.
22.4.5.1 Programming Examples
Single-buffer Transfer (Row 1)
1. Read the Channel Handler Status Register DMAC_CHSR.ENAx Field to choose a free (disabled)
channel.
2. Clear any pending interrupts on the channel from the previous DMAC transfer by reading the interrupt status
register, DMAC_EBCISR.
3. Program the following channel registers:
a. Write the starting source address in the DMAC_SADDRx register for channel x.
b. Write the starting destination address in the DMAC_DADDRx register for channel x.
c. Write the next descriptor address in the DMA_DSCRx register for channel x with 0x0..
d. Program DMAC_CTRLAx, DMAC_CTRLBx and DMAC_CFGx according to Row 1 as shown in Table
22-4 on page 345.
e. Write the control information for the DMAC transfer in the DMAC_CTRLAx and DMAC_CTRLBx reg-
isters for channel x. For example, in the register, you can program the following:
̶i. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow
control device by programming the FC of the DMAC_CTRLBx register.
̶ii. Set up the transfer characteristics, such as:
–Transfer width for the source in the SRC_WIDTH field.
–Transfer width for the destination in the DST_WIDTH field.
– Incrementing/decrementing or fixed address for source in SRC_INC field.
– Incrementing/decrementing or fixed address for destination in DST_INC field.
f. Write the channel configuration information into the DMAC_CFGx register for channel x.
̶i. Designate the handshaking interface type (hardware or software) for the source and destination
peripherals. This is not required for memory. This step requires programming the
SRC_H2SEL/DST_H2SEL bits, respectively. Writing a ‘1’ activates the hardware handshaking
interface to handle source/destination requests. Writing a ‘0’ activates the software handshaking
interface to handle source/destination requests.
̶ii. If the hardware handshaking interface is activated for the source or destination peripheral, assign a
handshaking interface to the source and destination peripheral. This requires programming the
SRC_PER and DST_PER bits, respectively.
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4. After the DMAC selected channel has been programmed, enable the channel by writing a ‘1’ to the
DMAC_CHER.ENAx bit, where x is the channel number. Make sure that bit 0 of DMAC_EN.ENABLE
register is enabled.
5. Source and destination request single and chunk DMAC transactions to transfer the buffer of data (assuming
non-memory peripherals). The DMAC acknowledges at the completion of every transaction (chunk and
single) in the buffer and carries out the buffer transfer.
6. Once the transfer completes, the hardware sets the interrupts and disables the channel. At this time, you can
either respond to the Buffer Transfer Completed Interrupt or Chained Buffer Transfer Completed Interrupt, or
poll for the Channel Handler Status Register (DMAC_CHSR.ENAx) bit until it is cleared by hardware, to
detect when the transfer is complete.
Multi-buffer Transfer with Linked List for Source and Linked List for Destination (Row 4)
1. Read the Channel Handler Status register to choose a free (disabled) channel.
2. Set up the chain of Linked List Items (otherwise known as buffer descriptors) in memory. Write the control
information in the LLI.DMAC_CTRLAx and LLI.DMAC_CTRLBx registers location of the buffer descriptor for
each LLI in memory (see Figure 22-5 on page 348) for channel x. For example, in the register, you can
program the following:
a.Set up the transfer type (memory or non-memory peripheral for source and destination) and flow con-
trol device by programming the FC of the DMAC_CTRLBx register.
b.Set up the transfer characteristics, such as:
̶i. Transfer width for the source in the SRC_WIDTH field.
̶ii. Transfer width for the destination in the DST_WIDTH field.
̶v. Incrementing/decrementing or fixed address for source in SRC_INCR field.
̶vi. Incrementing/decrementing or fixed address for destination DST_INCR field.
3. Write the channel configuration information into the DMAC_CFGx register for channel x.
a.Designate the handshaking interface type (hardware or software) for the source and destination
peripherals. This is not required for memory. This step requires programming the
SRC_H2SEL/DST_H2SEL bits, respectively. Writing a ‘1’ activates the hardware handshaking inter-
face to handle source/destination requests for the specific channel. Writing a ‘0’ activates the
software handshaking interface to handle source/destination requests.
b. If the hardware handshaking interface is activated for the source or destination peripheral, assign the
handshaking interface to the source and destination peripheral. This requires programming the
SRC_PER and DST_PER bits, respectively.
4. Make sure that the LLI.DMAC_CTRLBx register locations of all LLI entries in memory (except the last) are
set as shown in Row 4 of Table 22-4 on page 345. The LLI.DMAC_CTRLBx register of the last Linked List
Item must be set as described in Row 1 of Table 22-4. Figure 22-4 on page 345 shows a Linked List
example with two list items.
5. Make sure that the LLI.DMAC_DSCRx register locations of all LLI entries in memory (except the last) are
non-zero and point to the base address of the next Linked List Item.
6. Make sure that the LLI.DMAC_SADDRx/LLI.DMAC_DADDRx register locations of all LLI entries in memory
point to the start source/destination buffer address preceding that LLI fetch.
7. Make sure that the LLI.DMAC_CTRLAx.DONE field of the LLI.DMAC_CTRLAx register locations of all LLI
entries in memory are cleared.
8. Clear any pending interrupts on the channel from the previous DMAC transfer by reading the status register:
DMAC_EBCISR.
9. Program the DMAC_CTRLBx, DMAC_CFGx registers according to Row 4 as shown in Table 22-4 on page
345.
10. Program the DMAC_DSCRx register with DMAC_DSCRx(0), the pointer to the first Linked List item.
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11. Finally, enable the channel by writing a ‘1’ to the DMAC_CHER.ENAx bit, where x is the channel number.
The transfer is performed.
12. The DMAC fetches the first LLI from the location pointed to by DMAC_DSCRx(0).
Note: The LLI.DMAC_SADDRx, LLI. DMAC_DADDRx, LLI.DMAC_DSCRx, LLI.DMAC_CTRLAx and LLI.DMAC_CTRLBx
registers are fetched. The DMAC automatically reprograms the DMAC_SADDRx, DMAC_DADDRx, DMAC_DSCRx,
DMAC_CTRLBx and DMAC_CTRLAx channel registers from the DMAC_DSCRx(0).
13. Source and destination request single and chunk DMAC transactions to transfer the buffer of data (assuming
non-memory peripheral). The DMAC acknowledges at the completion of every transaction (chunk and
single) in the buffer and carries out the buffer transfer.
14. Once the buffer of data is transferred, the DMAC_CTRLAx register is written out to system memory at the
same location and on the same layer where it was originally fetched, that is, the location of the
DMAC_CTRLAx register of the linked list item fetched prior to the start of the buffer transfer. Only
DMAC_CTRLAx register is written out because only the DMAC_CTRLAx.BTSIZE and
DMAC_CTRLAX.DONE bits have been updated by DMAC hardware. Additionally, the
DMAC_CTRLAx.DONE bit is asserted when the buffer transfer has completed.
Note: Do not poll the DMAC_CTRLAx.DONE bit in the DMAC memory map. Instead, poll the LLI.DMAC_CTRLAx.DONE bit
in the LLI for that buffer. If the poll LLI.DMAC_CTRLAx.DONE bit is asserted, then this buffer transfer has completed.
This LLI.DMAC_CTRLAx.DONE bit was cleared at the start of the transfer.
15. The DMAC does not wait for the buffer interrupt to be cleared, but continues fetching the next LLI from the
memory location pointed to by current DMAC_DSCRx register and automatically reprograms the
DMAC_SADDRx, DMAC_DADDRx, DMAC_DSCRx, DMAC_CTRLAx and DMAC_CTRLBx channel
registers. The DMAC transfer continues until the DMAC determines that the DMAC_CTRLBx and
DMAC_DSCRx registers at the end of a buffer transfer match described in Row 1 of Table 22-4 on page
345. The DMAC then knows that the previous buffer transferred was the last buffer in the DMAC transfer.
The DMAC transfer might look like that shown in Figure 22-5 on page 348.
Figure 22-5. Multi-buffer with Linked List Address for Source and Destination
If the user needs to execute a DMAC transfer where the source and destination address are contiguous but the
amount of data to be transferred is greater than the maximum buffer size DMAC_CTRLAx.BTSIZE, then this can
be achieved using the type of multi-buffer transfer as shown in Figure 22-6 on page 349.
SADDR(2)
SADDR(1)
SADDR(0)
DADDR(2)
DADDR(1)
DADDR(0)
Buffer 2
Buffer 1
Buffer 0 Buffer 0
Buffer 1
Buffer 2
Address of
Source Layer
Address of
Destination Layer
Source BuffersDestination Buffers
////
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Figure 22-6. Multi-buffer with Linked Address for Source and Destination Buffers are Contiguous
The DMAC transfer flow is shown in Figure 22-7 on page 350.
SADDR(2)
SADDR(1)
SADDR(0)
DADDR(2)
DADDR(1)
DADDR(0)
Buffer 2
Buffer 1
Buffer 0
Buffer 0
Buffer 1
Buffer 2
Address of
Source Layer Address of
Destination Layer
Source BuffersDestination Buffers
SADDR(3)
Buffer 2
DADDR(3)
Buffer 2
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Figure 22-7. DMAC Transfer Flow for Source and Destination Linked List Address
̶i. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow
control device by programming the FC of the DMAC_CTRLBx register.
̶i. Designate the handshaking interface type (hardware or software) for the source and destination
peripherals. This is not required for memory. This step requires programming the
SRC_H2SEL/DST_h2SEL bits, respectively. Writing a ‘1’ activates the hardware handshaking
interface to handle source/destination requests for the specific channel. Writing a ‘0’ activates the
software handshaking interface to handle source/destination requests.
Channel enabled by
software
LLI Fetch
Hardware reprograms
SADDRx, DADDRx, CTRLA/Bx, DSCRx
DMAC buffer transfer
Writeback of DMAC_CTRLAx
register in system memory
Is DMAC in
Row 1 of
DMAC State Machine Table?
Channel disabled by
hardware
Chained Buffer Transfer Completed
Interrupt generated here
DMAC Chained Buffer Transfer
Completed Interrupt generated here yes
no
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̶ii. If the hardware handshaking interface is activated for the source or destination peripheral, assign
handshaking interface to the source and destination peripheral. This requires programming the
SRC_PER and DST_PER bits, respectively.
16. Source and destination request single and chunk DMAC transactions to transfer the buffer of data (assuming
non-memory peripherals). The DMAC acknowledges on completion of each chunk/single transaction and
carries out the buffer transfer.
a.Set up the transfer type (memory or non-memory peripheral for source and destination) and flow con-
trol peripheral by programming the FC of the DMAC_CTRLBx register.
a.Designate the handshaking interface type (hardware or software) for the source and destination
peripherals. This is not required for memory. This step requires programming the
SRC_H2SEL/DST_H2SEL bits, respectively. Writing a ‘1’ activates the hardware handshaking inter-
face to handle source/destination requests for the specific channel. Writing a ‘0’ activates the
software handshaking interface source/destination requests.
b.If the hardware handshaking interface is activated for the source or destination peripheral, assign
handshaking interface to the source and destination peripheral. This requires programming the
SRC_PER and DST_PER bits, respectively.
17. Source and destination request single and chunk DMAC transactions to transfer the buffer of data (assuming
non-memory peripherals). DMAC acknowledges at the completion of every transaction (chunk and single) in
the buffer and carries out the buffer transfer.
̶i. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow
control device by programming the FC of the DMAC_CTRLBx register.
̶i. Designate the handshaking interface type (hardware or software) for the source and destination
peripherals. This is not required for memory. This step requires programming the
SRC_H2SEL/DST_H2SEL bits, respectively. Writing a ‘1’ activates the hardware handshaking
interface to handle source/destination requests for the specific channel. Writing a ‘0’ activates the
software handshaking interface to handle source/destination requests.
̶ii. If the hardware handshaking interface is activated for the source or destination peripheral, assign
the handshaking interface to the source and destination peripheral. This requires programming the
SRC_PER and DST_PER bits, respectively.
18. Source and destination request single and chunk DMAC transactions to transfer the buffer of data (assuming
non-memory peripherals). The DMAC acknowledges at the completion of every transaction (chunk and
single) in the buffer and carries out the buffer transfer.
Multi-buffer DMAC Transfer with Linked List for Source and Contiguous Destination Address (Row 2)
1. Read the Channel Handler Status register to choose a free (disabled) channel.
2. Set up the linked list in memory. Write the control information in the LLI.DMAC_CTRLAx and
LLI.DMAC_CTRLBx register location of the buffer descriptor for each LLI in memory for channel x. For
example, in the register, you can program the following:
a.Set up the transfer type (memory or non-memory peripheral for source and destination) and flow con-
trol device by programming the FC of the DMAC_CTRLBx register.
b.Set up the transfer characteristics, such as:
̶i. Transfer width for the source in the SRC_WIDTH field.
̶ii. Transfer width for the destination in the DST_WIDTH field.
̶v. Incrementing/decrementing or fixed address for source in SRC_INCR field.
̶vi. Incrementing/decrementing or fixed address for destination DST_INCR field.
3. Write the starting destination address in the DMAC_DADDRx register for channel x.
Note: The values in the LLI.DMAC_DADDRx register location of each Linked List Item (LLI) in memory, although fetched
during an LLI fetch, are not used.
4. Write the channel configuration information into the DMAC_CFGx register for channel x.
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a.Designate the handshaking interface type (hardware or software) for the source and destination
peripherals. This is not required for memory. This step requires programming the
SRC_H2SEL/DST_H2SEL bits, respectively. Writing a ‘1’ activates the hardware handshaking inter-
face to handle source/destination requests for the specific channel. Writing a ‘0’ activates the
software handshaking interface to handle source/destination requests.
b. If the hardware handshaking interface is activated for the source or destination peripheral, assign the
handshaking interface to the source and destination peripherals. This requires programming the
SRC_PER and DST_PER bits, respectively.
5. Make sure that all LLI.DMAC_CTRLBx register locations of the LLI (except the last) are set as shown in Row
2 of Table 22-4 on page 345, while the LLI.DMAC_CTRLBx register of the last Linked List item must be set
as described in Row 1 of Table 22-4. Figure 22-4 on page 345 shows a Linked List example with two list
items.
6. Make sure that the LLI.DMAC_DSCRx register locations of all LLIs in memory (except the last) are non-zero
and point to the next Linked List Item.
7. Make sure that the LLI.DMAC_SADDRx register locations of all LLIs in memory point to the start source
buffer address proceeding that LLI fetch.
8. Make sure that the LLI.DMAC_CTRLAx.DONE field of the LLI.DMAC_CTRLAx register locations of all LLIs
in memory is cleared.
9. Clear any pending interrupts on the channel from the previous DMAC transfer by reading the interrupt status
register.
10. Program the DMAC_CTRLAx, DMAC_CTRLBx and DMAC_CFGx registers according to Row 2 as shown in
Table 22-4 on page 345
11. Program the DMAC_DSCRx register with DMAC_DSCRx(0), the pointer to the first Linked List item.
12. Finally, enable the channel by writing a ‘1’ to the DMAC_CHER.ENAx bit. The transfer is performed. Make
sure that bit 0 of the DMAC_EN register is enabled.
13. The DMAC fetches the first LLI from the location pointed to by DMAC_DSCRx(0).
Note: The LLI.DMAC_SADDRx, LLI.DMAC_DADDRx, LLI.DMAC_DSCRx and LLI.DMAC_CTRLA/Bx registers are fetched.
The LLI.DMAC_DADDRx register location of the LLI, although fetched, is not used. The DMAC_DADDRx register in
the DMAC remains unchanged.
14. Source and destination requests single and chunk DMAC transactions to transfer the buffer of data
(assuming non-memory peripherals). The DMAC acknowledges at the completion of every transaction
(chunk and single) in the buffer and carries out the buffer transfer.
15. Once the buffer of data is transferred, the DMAC_CTRLAx register is written out to the system memory at
the same location and on the same layer (DMAC_DSCRx.DSCR_IF) where it was originally fetched, that is,
the location of the DMAC_CTRLAx register of the linked list item fetched prior to the start of the buffer
transfer. Only DMAC_CTRLAx register is written out because only the DMAC_CTRLAx.BTSIZE and
DMAC_CTRLAX.DONE fields have been updated by DMAC hardware. Additionally, the
DMAC_CTRLAx.DONE bit is asserted when the buffer transfer has completed.
Note: Do not poll the DMAC_CTRLAx.DONE bit in the DMAC memory map. Instead, poll the LLI.DMAC_CTRLAx.DONE bit
in the LLI for that buffer. If the poll LLI.DMAC_CTRLAx.DONE bit is asserted, then this buffer transfer has completed.
This LLI.DMAC_CTRLAx.DONE bit was cleared at the start of the transfer.
16. The DMAC does not wait for the buffer interrupt to be cleared, but continues and fetches the next LLI from
the memory location pointed to by the current DMAC_DSCRx register, then automatically reprograms the
DMAC_SADDRx, DMAC_CTRLAx, DMAC_CTRLBx and DMAC_DSCRx channel registers. The
DMAC_DADDRx register is left unchanged. The DMAC transfer continues until the DMAC samples the
DMAC_CTRLAx, DMAC_CTRLBx and DMAC_DSCRx registers at the end of a buffer transfer match that
described in Row 1 of Table 22-4 on page 345. The DMAC then knows that the previous buffer transferred
was the last buffer in the DMAC transfer.
The DMAC transfer might look like that shown in Figure 22-8 on page 353. Note that the destination address is
decrementing.
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Figure 22-8. DMAC Transfer with Linked List Source Address and Contiguous Destination Address
The DMAC transfer flow is shown in Figure 22-9 on page 354.
SADDR(2)
SADDR(1)
SADDR(0)
DADDR(2)
DADDR(1)
DADDR(0)
Buffer 2
Buffer 1
Buffer 0
Buffer 0
Buffer 1
Buffer 2
Address of
Source Layer Address of
Destination Layer
Source BuffersDestination Buffers
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Figure 22-9. DMAC Transfer Flow for Linked List Source Address and Contiguous Destination Address
Channel enabled by
software
LLI Fetch
Hardware reprograms
SADDRx, CTRLAx,CTRLBx, DSCRx
DMAC buffer transfer
Writeback of control
information of LLI
Is DMAC in
Row 1 ?
Channel disabled by
hardware
Buffer Transfer Completed
Interrupt generated here
DMAC Chained Buffer Transfer
Completed Interrupt generated here yes
no
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22.4.6 Disabling a Channel Prior to Transfer Completion
Under normal operation, the software enables a channel by writing a ‘1’ to the Channel Handler Enable Register,
DMAC_CHER.ENAx, and the hardware disables a channel on transfer completion by clearing the
DMAC_CHSR.ENAx register bit.
The recommended way for software to disable a channel without losing data is to use the SUSPx bit in conjunction
with the EMPTx bit in the Channel Handler Status Register.
1. If the software wishes to disable a channel n prior to the DMAC transfer completion, then it can set the
DMAC_CHER.SUSPx bit to tell the DMAC to halt all transfers from the source peripheral. Therefore, the
channel FIFO receives no new data.
2. The software can now poll the DMAC_CHSR.EMPTx bit until it indicates that the channel n FIFO is empty,
where n is the channel number.
3. The DMAC_CHER.ENAx bit can then be cleared by software once the channel n FIFO is empty, where n is
the channel number.
When DMAC_CTRLAx.SRC_WIDTH is less than DMAC_CTRLAx.DST_WIDTH and the DMAC_CHSRx.SUSPx
bit is high, the DMAC_CHSRx.EMPTx is asserted once the contents of the FIFO does not permit a single word of
DMAC_CTRLAx.DST_WIDTH to be formed. However, there may still be data in the channel FIFO but not enough
to form a single transfer of DMAC_CTLx.DST_WIDTH width. In this configuration, once the channel is disabled,
the remaining data in the channel FIFO are not transferred to the destination peripheral. It is permitted to remove
the channel from the suspension state by writing a ‘1’ to the DMAC_CHER.RESx field register. The DMAC transfer
completes in the normal manner. n defines the channel number.
Note: If a channel is disabled by software, an active single or chunk transaction is not guaranteed to receive an
acknowledgement.
22.4.6.1 Abnormal Transfer Termination
A DMAC transfer may be terminated abruptly by software by clearing the channel enable bit, DMAC_CHDR.ENAx,
where x is the channel number. This does not mean that the channel is disabled immediately after the
DMAC_CHSR.ENAx bit is cleared over the APB interface. Consider this as a request to disable the channel. The
DMAC_CHSR.ENAx must be polled and then it must be confirmed that the channel is disabled by reading back 0.
The software may terminate all channels abruptly by clearing the global enable bit in the DMAC Configuration
Register (DMAC_EN.ENABLE bit). Again, this does not mean that all channels are disabled immediately after the
DMAC_EN.ENABLE is cleared over the APB slave interface. Consider this as a request to disable all channels.
The DMAC_CHSR.ENABLE must be polled and then it must be confirmed that all channels are disabled by
reading back ‘0’.
Note: If the channel enable bit is cleared while there is data in the channel FIFO, this data is not sent to the destination
peripheral and is not present when the channel is re-enabled. For read sensitive source peripherals, such as a source
FIFO, this data is therefore lost. When the source is not a read sensitive device (i.e., memory), disabling a channel
without waiting for the channel FIFO to empty may be acceptable as the data is available from the source peripheral
upon request and is not lost.
Note: If a channel is disabled by software, an active single or chunk transaction is not guaranteed to receive an
acknowledgement.
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22.5 DMAC Software Requirements
There must not be any write operation to Channel registers in an active channel after the channel enable is
made HIGH. If any channel parameters must be reprogrammed, this can only be done after disabling the
DMAC channel.
When the destination peripheral has been defined as the flow controller, source single transfer requests are
not serviced until the destination peripheral has asserted its Last Transfer Flag.
When the source peripheral has been defined as the flow controller, destination single transfer requests are
not serviced until the source peripheral has asserted its Last Transfer Flag.
When the destination peripheral has been defined as the flow controller, if the destination width is smaller
than the source width, then a data loss may occur, and the loss is equal to the Source Single Transfer size in
bytes- destination Single Transfer size in bytes.
When a Memory to Peripheral transfer occurs, if the destination peripheral has been defined as the flow
controller, then a prefetch operation is performed. It means that data is extracted from the memory before
any request from the peripheral is generated.
You must program the DMAC_SADDRx and DMAC_DADDRx channel registers with a byte, half-word and
word aligned address depending on the source width and destination width.
After the software disables a channel by writing into the channel disable register, it must re-enable the
channel only after it has polled a 0 in the corresponding channel enable status register. This is because the
current AHB Burst must terminate properly.
If you program the BTSIZE field in the DMAC_CTRLA as zero, and the DMAC has been defined as the flow
controller, then the channel is automatically disabled.
When hardware handshaking interface protocol is fully implemented, a peripheral is expected to deassert
any sreq or breq signals on receiving the ack signal irrespective of the request the ack was asserted in
response to.
Multiple Transfers involving the same peripheral must not be programmed and enabled on different
channels, unless this peripheral integrates several hardware handshaking interfaces.
When a Peripheral has been defined as the flow controller, the targeted DMAC Channel must be enabled
before the Peripheral. If you do not ensure this and the First DMAC request is also the last transfer, the
DMAC Channel might miss a Last Transfer Flag.
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22.6 Write Protection Registers
To prevent any single software error that may corrupt the DMAC behavior, the DMAC address space can be write-
protected by setting the WPEN bit in the “DMAC Write Protect Mode Register” (DMAC_WPMR).
If a write access to anywhere in the DMAC address space is detected, then the WPVS flag in the DMAC Write
Protect Status Register (MCI_WPSR) is set, and the WPVSRC field indicates in which register the write access
has been attempted.
The WPVS flag is reset by writing the DMAC Write Protect Mode Register (DMAC_WPMR) with the appropriate
access key, WPKEY.
The protected registers are:
“DMAC Global Configuration Register” on page 359
“DMAC Enable Register” on page 360
“DMAC Channel x [x = 0..5] Source Address Register” on page 371
“DMAC Channel x [x = 0..5] Destination Address Register” on page 372
“DMAC Channel x [x = 0..5] Descriptor Address Register” on page 373
“DMAC Channel x [x = 0..5] Control A Register” on page 374
“DMAC Channel x [x = 0..5] Control B Register” on page 376
“DMAC Channel x [x = 0..5] Configuration Register” on page 378
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22.7 AHB DMA Controller (DMAC) User Interface
Table 22-5. Register Mapping
Offset Register Name Access Reset
0x000 DMAC Global Configuration Register DMAC_GCFG Read-write 0x10
0x004 DMAC Enable Register DMAC_EN Read-write 0x0
0x008 DMAC Software Single Request Register DMAC_SREQ Read-write 0x0
0x00C DMAC Software Chunk Transfer Request Register DMAC_CREQ Read-write 0x0
0x010 DMAC Software Last Transfer Flag Register DMAC_LAST Read-write 0x0
0x014 Reserved
0x018 DMAC Error, Chained Buffer Transfer Completed Interrupt and
Buffer Transfer Completed Interrupt Enable register. DMAC_EBCIER Write-only –
0x01C DMAC Error, Chained Buffer Transfer Completed Interrupt and
Buffer Transfer Completed Interrupt Disable register. DMAC_EBCIDR Write-only –
0x020 DMAC Error, Chained Buffer Transfer Completed Interrupt and
Buffer transfer completed Mask Register. DMAC_EBCIMR Read-only 0x0
0x024 DMAC Error, Chained Buffer Transfer Completed Interrupt and
Buffer transfer completed Status Register. DMAC_EBCISR Read-only 0x0
0x028 DMAC Channel Handler Enable Register DMAC_CHER Write-only –
0x02C DMAC Channel Handler Disable Register DMAC_CHDR Write-only –
0x030 DMAC Channel Handler Status Register DMAC_CHSR Read-only 0x00FF0000
0x034 Reserved – – –
0x038 Reserved – – –
0x03C+ch_num*(0x28)+(0x0) DMAC Channel Source Address Register DMAC_SADDR Read-write 0x0
0x03C+ch_num*(0x28)+(0x4) DMAC Channel Destination Address Register DMAC_DADDR Read-write 0x0
0x03C+ch_num*(0x28)+(0x8) DMAC Channel Descriptor Address Register DMAC_DSCR Read-write 0x0
0x03C+ch_num*(0x28)+(0xC) DMAC Channel Control A Register DMAC_CTRLA Read-write 0x0
0x03C+ch_num*(0x28)+(0x10) DMAC Channel Control B Register DMAC_CTRLB Read-write 0x0
0x03C+ch_num*(0x28)+(0x14) DMAC Channel Configuration Register DMAC_CFG Read-write 0x01000000
0x03C+ch_num*(0x28)+(0x18) Reserved – – –
0x03C+ch_num*(0x28)+(0x1C) Reserved – – –
0x03C+ch_num*(0x28)+(0x20) Reserved – – –
0x03C+ch_num*(0x28)+(0x24) Reserved – – –
0x1E4 DMAC Write Protect Mode Register DMAC_WPMR Read-write 0x0
0x1E8 DMAC Write Protect Status Register DMAC_WPSR Read-only 0x0
0x01EC- 0x1FC Reserved – – –
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22.7.1 DMAC Global Configuration Register
Name: DMAC_GCFG
Address: 0x400C4000
Access: Read-write
Reset: 0x00000010
Note: Bit fields 0, 1, 2, 3, have a default value of 0. This should not be changed.
This register can only be written if the WPEN bit is cleared in “DMAC Write Protect Mode Register” .
• ARB_CFG: Arbiter Configuration
0 (FIXED): Fixed priority arbiter.
1 (ROUND_ROBIN): Modified round robin arbiter.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––ARB_CFG––––
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22.7.2 DMAC Enable Register
Name: DMAC_EN
Address: 0x400C4004
Access: Read-write
Reset: 0x00000000
This register can only be written if the WPEN bit is cleared in “DMAC Write Protect Mode Register” .
• ENABLE
0: DMA Controller is disabled.
1: DMA Controller is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––ENABLE
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22.7.3 DMAC Software Single Request Register
Name: DMAC_SREQ
Address: 0x400C4008
Access: Read-write
Reset: 0x00000000
• DSREQx: Destination Request
Request a destination single transfer on channel i.
• SSREQx: Source Request
Request a source single transfer on channel i.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––DSREQ5SSREQ5DSREQ4SSREQ4
76543210
DSREQ3 SSREQ3 DSREQ2 SSREQ2 DSREQ1 SSREQ1 DSREQ0 SSREQ0
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22.7.4 DMAC Software Chunk Transfer Request Register
Name: DMAC_CREQ
Address: 0x400C400C
Access: Read-write
Reset: 0x00000000
• DCREQx: Destination Chunk Request
Request a destination chunk transfer on channel i.
• SCREQx: Source Chunk Request
Request a source chunk transfer on channel i.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––DCREQ5 SCREQ5 DCREQ4 SCREQ4
76543210
DCREQ3 SCREQ3 DCREQ2 SCREQ2 DCREQ1 SCREQ1 DCREQ0 SCREQ0
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22.7.5 DMAC Software Last Transfer Flag Register
Name: DMAC_LAST
Address: 0x400C4010
Access: Read-write
Reset: 0x00000000
• DLASTx: Destination Last
Writing one to DLASTx prior to writing one to DSREQx or DCREQx indicates that this destination request is the last trans-
fer of the buffer.
• SLASTx: Source Last
Writing one to SLASTx prior to writing one to SSREQx or SCREQx indicates that this source request is the last transfer of
the buffer.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––DLAST5SLAST5DLAST4SLAST4
76543210
DLAST3 SLAST3 DLAST2 SLAST2 DLAST1 SLAST1 DLAST0 SLAST0
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22.7.6 DMAC Error, Buffer Transfer and Chained Buffer Transfer Interrupt Enable Register
Name: DMAC_EBCIER
Address: 0x400C4018
Access: Write-only
Reset: 0x00000000
• BTCx: Buffer Transfer Completed [5:0]
Buffer Transfer Completed Interrupt Enable Register. Set the relevant bit in the BTC field to enable the interrupt for channel
i.
• CBTCx: Chained Buffer Transfer Completed [5:0]
Chained Buffer Transfer Completed Interrupt Enable Register. Set the relevant bit in the CBTC field to enable the interrupt
for channel i.
• ERRx: Access Error [5:0]
Access Error Interrupt Enable Register. Set the relevant bit in the ERR field to enable the interrupt for channel i.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– – ERR5 ERR4 ERR3 ERR2 ERR1 ERR0
15 14 13 12 11 10 9 8
– – CBTC5 CBTC4 CBTC3 CBTC2 CBTC1 CBTC0
76543210
– – BTC5 BTC4 BTC3 BTC2 BTC1 BTC0
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22.7.7 DMAC Error, Buffer Transfer and Chained Buffer Transfer Interrupt Disable Register
Name: DMAC_EBCIDR
Address: 0x400C401C
Access: Write-only
Reset: 0x00000000
• BTCx: Buffer Transfer Completed [5:0]
Buffer transfer completed Disable Interrupt Register. When set, a bit of the BTC field disables the interrupt from the rele-
vant DMAC channel.
• CBTCx: Chained Buffer Transfer Completed [5:0]
Chained Buffer transfer completed Disable Register. When set, a bit of the CBTC field disables the interrupt from the rele-
vant DMAC channel.
• ERRx: Access Error [5:0]
Access Error Interrupt Disable Register. When set, a bit of the ERR field disables the interrupt from the relevant DMAC
channel.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– – ERR5 ERR4 ERR3 ERR2 ERR1 ERR0
15 14 13 12 11 10 9 8
– – CBTC5 CBTC4 CBTC3 CBTC2 CBTC1 CBTC0
76543210
– – BTC5 BTC4 BTC3 BTC2 BTC1 BTC0
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22.7.8 DMAC Error, Buffer Transfer and Chained Buffer Transfer Interrupt Mask Register
Name: DMAC_EBCIMR
Address: 0x400C4020
Access: Read-only
Reset: 0x00000000
• BTCx: Buffer Transfer Completed [5:0]
0: Buffer Transfer Completed Interrupt is disabled for channel i.
1: Buffer Transfer Completed Interrupt is enabled for channel i.
• CBTCx: Chained Buffer Transfer Completed [5:0]
0: Chained Buffer Transfer interrupt is disabled for channel i.
1: Chained Buffer Transfer interrupt is enabled for channel i.
• ERRx: Access Error [5:0]
0: Transfer Error Interrupt is disabled for channel i.
1: Transfer Error Interrupt is enabled for channel i.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– – ERR5 ERR4 ERR3 ERR2 ERR1 ERR0
15 14 13 12 11 10 9 8
– – CBTC5 CBTC4 CBTC3 CBTC2 CBTC1 CBTC0
76543210
– – BTC5 BTC4 BTC3 BTC2 BTC1 BTC0
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22.7.9 DMAC Error, Buffer Transfer and Chained Buffer Transfer Status Register
Name: DMAC_EBCISR
Address: 0x400C4024
Access: Read-only
Reset: 0x00000000
• BTCx: Buffer Transfer Completed [5:0]
When BTC[i] is set, Channel i buffer transfer has terminated.
• CBTCx: Chained Buffer Transfer Completed [5:0]
When CBTC[i] is set, Channel i Chained buffer has terminated. LLI Fetch operation is disabled.
• ERRx: Access Error [5:0]
When ERR[i] is set, Channel i has detected an AHB Read or Write Error Access.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– – ERR5 ERR4 ERR3 ERR2 ERR1 ERR0
15 14 13 12 11 10 9 8
– – CBTC5 CBTC4 CBTC3 CBTC2 CBTC1 CBTC0
76543210
– – BTC5 BTC4 BTC3 BTC2 BTC1 BTC0
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22.7.10 DMAC Channel Handler Enable Register
Name: DMAC_CHER
Address: 0x400C4028
Access: Write-only
Reset: 0x00000000
• ENAx: Enable [5:0]
When set, a bit of the ENA field enables the relevant channel.
• SUSPx: Suspend [5:0]
When set, a bit of the SUSP field freezes the relevant channel and its current context.
• KEEPx: Keep on [5:0]
When set, a bit of the KEEP field resumes the current channel from an automatic stall state.
31 30 29 28 27 26 25 24
– – KEEP5 KEEP4 KEEP3 KEEP2 KEEP1 KEEP0
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – SUSP5 SUSP4 SUSP3 SUSP2 SUSP1 SUSP0
76543210
– – ENA5 ENA4 ENA3 ENA2 ENA1 ENA0
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22.7.11 DMAC Channel Handler Disable Register
Name: DMAC_CHDR
Address: 0x400C402C
Access: Write-only
Reset: 0x00000000
• DISx: Disable [5:0]
Write one to this field to disable the relevant DMAC Channel. The content of the FIFO is lost and the current AHB access is
terminated. Software must poll DIS[5:0] field in the DMAC_CHSR register to be sure that the channel is disabled.
• RESx: Resume [5:0]
Write one to this field to resume the channel transfer restoring its context.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – RES5 RES4 RES3 RES2 RES1 RES0
76543210
– – DIS5 DIS4 DIS3 DIS2 DIS1 DIS0
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22.7.12 DMAC Channel Handler Status Register
Name: DMAC_CHSR
Address: 0x400C4030
Access: Read-only
Reset: 0x00FF0000
• ENAx: Enable [5:0]
A one in any position of this field indicates that the relevant channel is enabled.
• SUSPx: Suspend [5:0]
A one in any position of this field indicates that the channel transfer is suspended.
• EMPTx: Empty [5:0]
A one in any position of this field indicates that the relevant channel is empty.
• STALx: Stalled [5:0]
A one in any position of this field indicates that the relevant channel is stalling.
31 30 29 28 27 26 25 24
– – STAL5 STAL4 STAL3 STAL2 STAL1 STAL0
23 22 21 20 19 18 17 16
– – EMPT5 EMPT4 EMPT3 EMPT2 EMPT1 EMPT0
15 14 13 12 11 10 9 8
– – SUSP5 SUSP4 SUSP3 SUSP2 SUSP1 SUSP0
76543210
– – ENA5 ENA4 ENA3 ENA2 ENA1 ENA0
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22.7.13 DMAC Channel x [x = 0..5] Source Address Register
Name: DMAC_SADDRx [x = 0..5]
Address: 0x400C403C [0], 0x400C4064 [1], 0x400C408C [2], 0x400C40B4 [3], 0x400C40DC [4], 0x400C4104 [5]
Access: Read-write
Reset: 0x00000000
This register can only be written if the WPEN bit is cleared in “DMAC Write Protect Mode Register” .
• SADDR: Channel x Source Address
This register must be aligned with the source transfer width.
31 30 29 28 27 26 25 24
SADDR
23 22 21 20 19 18 17 16
SADDR
15 14 13 12 11 10 9 8
SADDR
76543210
SADDR
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22.7.14 DMAC Channel x [x = 0..5] Destination Address Register
Name: DMAC_DADDRx [x = 0..5]
Address: 0x400C4040 [0], 0x400C4068 [1], 0x400C4090 [2], 0x400C40B8 [3], 0x400C40E0 [4], 0x400C4108 [5]
Access: Read-write
Reset: 0x00000000
This register can only be written if the WPEN bit is cleared in “DMAC Write Protect Mode Register” .
• DADDR: Channel x Destination Address
This register must be aligned with the destination transfer width.
31 30 29 28 27 26 25 24
DADDR
23 22 21 20 19 18 17 16
DADDR
15 14 13 12 11 10 9 8
DADDR
76543210
DADDR
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22.7.15 DMAC Channel x [x = 0..5] Descriptor Address Register
Name: DMAC_DSCRx [x = 0..5]
Address: 0x400C4044 [0], 0x400C406C [1], 0x400C4094 [2], 0x400C40BC [3], 0x400C40E4 [4], 0x400C410C [5]
Access: Read-write
Reset: 0x00000000
This register can only be written if the WPEN bit is cleared in “DMAC Write Protect Mode Register” .
• DSCR: Buffer Transfer Descriptor Address
This address is word aligned.
31 30 29 28 27 26 25 24
DSCR
23 22 21 20 19 18 17 16
DSCR
15 14 13 12 11 10 9 8
DSCR
76543210
DSCR –
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22.7.16 DMAC Channel x [x = 0..5] Control A Register
Name: DMAC_CTRLAx [x = 0..5]
Address: 0x400C4048 [0], 0x400C4070 [1], 0x400C4098 [2], 0x400C40C0 [3], 0x400C40E8 [4], 0x400C4110 [5]
Access: Read-write
Reset: 0x00000000
This register can only be written if the WPEN bit is cleared in “DMAC Write Protect Mode Register” on page 380
• BTSIZE: Buffer Transfer Size
The transfer size relates to the number of transfers to be performed, that is, for writes it refers to the number of source
width transfers to perform when DMAC is flow controller. For Reads, BTSIZE refers to the number of transfers completed
on the Source Interface. When this field is set to 0, the DMAC module is automatically disabled when the relevant channel
is enabled.
• SCSIZE: Source Chunk Transfer Size.
31 30 29 28 27 26 25 24
DONE – DST_WIDTH – – SRC_WIDTH
23 22 21 20 19 18 17 16
– DCSIZE – SCSIZE
15 14 13 12 11 10 9 8
BTSIZE
76543210
BTSIZE
Value Name Description
000 CHK_1 1 data transferred
001 CHK_4 4 data transferred
010 CHK_8 8 data transferred
011 CHK_16 16 data transferred
100 CHK_32 32 data transferred
101 CHK_64 64 data transferred
110 CHK_128 128 data transferred
111 CHK_256 256 data transferred
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• DCSIZE: Destination Chunk Transfer Size
• SRC_WIDTH: Transfer Width for the Source
• DST_WIDTH: Transfer Width for the Destination
•DONE
0: The transfer is performed.
1: If SOD field of DMAC_CFG register is set to true, then the DMAC is automatically disabled when an LLI updates the
content of this register.
The DONE field is written back to memory at the end of the transfer.
Value Name Description
000 CHK_1 1 data transferred
001 CHK_4 4 data transferred
010 CHK_8 8 data transferred
011 CHK_16 16 data transferred
100 CHK_32 32 data transferred
101 CHK_64 64 data transferred
110 CHK_128 128 data transferred
111 CHK_256 256 data transferred
Value Name Description
00 BYTE the transfer size is set to 8-bit width
01 HALF_WORD the transfer size is set to 16-bit width
1X WORD the transfer size is set to 32-bit width
Value Name Description
00 BYTE the transfer size is set to 8-bit width
01 HALF_WORD the transfer size is set to 16-bit width
1X WORD the transfer size is set to 32-bit width
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22.7.17 DMAC Channel x [x = 0..5] Control B Register
Name: DMAC_CTRLBx [x = 0..5]
Address: 0x400C404C [0], 0x400C4074 [1], 0x400C409C [2], 0x400C40C4 [3], 0x400C40EC [4], 0x400C4114 [5]
Access: Read-write
Reset: 0x00000000
This register can only be written if the WPEN bit is cleared in “DMAC Write Protect Mode Register” .
• SRC_DSCR: Source Address Descriptor
0 (FETCH_FROM_MEM): Source address is updated when the descriptor is fetched from the memory.
1 (FETCH_DISABLE): Buffer Descriptor Fetch operation is disabled for the source.
• DST_DSCR: Destination Address Descriptor
0 (FETCH_FROM_MEM): Destination address is updated when the descriptor is fetched from the memory.
1 (FETCH_DISABLE): Buffer Descriptor Fetch operation is disabled for the destination.
• FC: Flow Control
This field defines which device controls the size of the buffer transfer, also referred to as the Flow Controller.
• SRC_INCR: Incrementing, Decrementing or Fixed Address for the Source
31 30 29 28 27 26 25 24
– IEN DST_INCR – – SRC_INCR
23 22 21 20 19 18 17 16
FC DST_DSCR – – – SRC_DSCR
15 14 13 12 11 10 9 8
–– –––––
76543210
–– – –– –
Value Name Description
000 MEM2MEM_DMA_FC Memory-to-Memory Transfer DMAC is flow controller
001 MEM2PER_DMA_FC Memory-to-Peripheral Transfer DMAC is flow controller
010 PER2MEM_DMA_FC Peripheral-to-Memory Transfer DMAC is flow controller
011 PER2PER_DMA_FC Peripheral-to-Peripheral Transfer DMAC is flow controller
Value Name Description
00 INCREMENTING The source address is incremented
01 DECREMENTING The source address is decremented
10 FIXED The source address remains unchanged
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• DST_INCR: Incrementing, Decrementing or Fixed Address for the Destination
•IEN
If this bit is cleared, when the buffer transfer is completed, the BTCx flag is set in the EBCISR status register. This bit is
active low.
Value Name Description
00 INCREMENTING The destination address is incremented
01 DECREMENTING The destination address is decremented
10 FIXED The destination address remains unchanged
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22.7.18 DMAC Channel x [x = 0..5] Configuration Register
Name: DMAC_CFGx [x = 0..5]
Address: 0x400C4050 [0], 0x400C4078 [1], 0x400C40A0 [2], 0x400C40C8 [3], 0x400C40F0 [4], 0x400C4118 [5]
Access: Read-write
Reset: 0x0100000000
This register can only be written if the WPEN bit is cleared in “DMAC Write Protect Mode Register” on page 380
• SRC_PER: Source with Peripheral identifier
Channel x Source Request is associated with peripheral identifier coded SRC_PER handshaking interface.
• DST_PER: Destination with Peripheral identifier
Channel x Destination Request is associated with peripheral identifier coded DST_PER handshaking interface.
• SRC_H2SEL: Software or Hardware Selection for the Source
0 (SW): Software handshaking interface is used to trigger a transfer request.
1 (HW): Hardware handshaking interface is used to trigger a transfer request.
• DST_H2SEL: Software or Hardware Selection for the Destination
0 (SW): Software handshaking interface is used to trigger a transfer request.
1 (HW): Hardware handshaking interface is used to trigger a transfer request.
• SOD: Stop On Done
0 (DISABLE): STOP ON DONE disabled, the descriptor fetch operation ignores DONE Field of CTRLA register.
1 (ENABLE): STOP ON DONE activated, the DMAC module is automatically disabled if DONE FIELD is set to 1.
• LOCK_IF: Interface Lock
0 (DISABLE): Interface Lock capability is disabled
1 (ENABLE): Interface Lock capability is enabled
• LOCK_B: Bus Lock
0 (DISABLE): AHB Bus Locking capability is disabled.
1(ENABLE): AHB Bus Locking capability is enabled.
31 30 29 28 27 26 25 24
– – FIFOCFG – AHB_PROT
23 22 21 20 19 18 17 16
– LOCK_IF_L LOCK_B LOCK_IF – – – SOD
15 14 13 12 11 10 9 8
– – DST_H2SEL – – – SRC_H2SEL –
76543210
DST_PER SRC_PER
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• LOCK_IF_L: Master Interface Arbiter Lock
0 (CHUNK): The Master Interface Arbiter is locked by the channel x for a chunk transfer.
1 (BUFFER): The Master Interface Arbiter is locked by the channel x for a buffer transfer.
• AHB_PROT: AHB Protection
AHB_PROT field provides additional information about a bus access and is primarily used to implement some level of
protection.
• FIFOCFG: FIFO Configuration
HPROT[3] HPROT[2] HPROT[1] HPROT[0] Description
1 Data access
AHB_PROT[0] 0: User Access
1: Privileged Access
AHB_PROT[1] 0: Not Bufferable
1: Bufferable
AHB_PROT[2] 0: Not cacheable
1: Cacheable
Value Name Description
00 ALAP_CFG The largest defined length AHB burst is performed on the destination AHB interface.
01 HALF_CFG When half FIFO size is available/filled, a source/destination request is serviced.
10 ASAP_CFG When there is enough space/data available to perform a single AHB access, then the
request is serviced.
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22.7.19 DMAC Write Protect Mode Register
Name: DMAC_WPMR
Address: 0x400C41E4
Access: Read-write
Reset: See Table 22-5
• WPEN: Write Protect Enable
0 = Disables the Write Protect if WPKEY corresponds to 0x444D4143 (“DMAC” in ASCII).
1 = Enables the Write Protect if WPKEY corresponds to 0x444D4143 (“DMAC” in ASCII).
Protects the registers:
•“DMAC Global Configuration Register” on page 359
•“DMAC Enable Register” on page 360
•“DMAC Channel x [x = 0..5] Source Address Register” on page 371
•“DMAC Channel x [x = 0..5] Destination Address Register” on page 372
•“DMAC Channel x [x = 0..5] Descriptor Address Register” on page 373
•“DMAC Channel x [x = 0..5] Control A Register” on page 374
•“DMAC Channel x [x = 0..5] Control B Register” on page 376
•“DMAC Channel x [x = 0..5] Configuration Register” on page 378
• WPKEY: Write Protect KEY
Should be written at value 0x50494F (“DMAC” in ASCII). Writing any other value in this field aborts the write operation of
the WPEN bit. Always reads as 0.
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
———————WPEN
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22.7.20 DMAC Write Protect Status Register
Name: DMAC_WPSR
Address: 0x400C41E8
Access: Read-only
Reset: See Table 22-5
• WPVS: Write Protect Violation Status
0 = No Write Protect Violation has occurred since the last read of the DMAC_WPSR register.
1 = A Write Protect Violation has occurred since the last read of the DMAC_WPSR register. If this violation is an unauthor-
ized attempt to write a protected register, the associated violation is reported into field WPVSRC.
• WPVSRC: Write Protect Violation Source
When WPVS is active, this field indicates the write-protected register (through address offset or code) in which a write
access has been attempted.
Note: Reading DMAC_WPSR automatically clears all fields.
31 30 29 28 27 26 25 24
————————
23 22 21 20 19 18 17 16
WPVSRC
15 14 13 12 11 10 9 8
WPVSRC
76543210
———————WPVS
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23. External Memory Bus
23.1 Description
The external memory bus allows external devices connection to the various embedded memory controllers of the
microcontroller. The external memory bus handles control, address and data bus of each embedded memory
controllers. The SAM3X embeds a Static Memory/NAND Flash/ECC Controller (SMC/NFC/ECC) and a SDR-
SDRAM Controller (SDR-SDRAMC). Furthermore, the external memory bus handles data transfers with up to
eight external devices, each assigned to eight address spaces. Data transfers are performed through a 8-bit or 16-
bit data bus, an address bus of up to 24 bits, up to eight chip select lines (NCS[7:0]) and several control pins that
are generally multiplexed between the different embedded memory controllers.
23.2 Embedded Characteristics
Only present on 144-pin SAM3X and 217-pin SAM3X8H(1) versions
Managing SMC, NAND Flash and SDR-SDRAM Controller accesses offering:
̶Up to 8 configurable chip selects
̶Programmable timing on a per chip select basis
̶16 Mbyte Address Space per Chip Select
̶8- or 16-bit Data Bus
̶Word, Halfword, Byte Transfers
̶Byte Write or Byte Select Lines
̶Programmable Setup, Pulse and Hold Time for Read Signals per Chip Select
̶Programmable Setup, Pulse and Hold Time for Write Signals per Chip Select
̶Programmable Data Float Time per Chip Select
̶External Wait Request
̶Automatic Switch to Slow Clock Mode
̶Asynchronous Read in Page Mode Supported: Page Size Ranges from 4 to 32 bytes
̶NAND Flash Controller supporting NAND Flash with Multiplexed Data/Address buses
̶Supports SLC NAND Flash technology
̶Supports Hardware Error Correcting Code (ECC), 1-bit error correction, 2-bit error detection
̶Detection and Correction by Software
̶Supports SDRAM with 8- or 16-bit Data Path (217-pin SAM3X8H(1))
Note: 1.This device is not commercially available. Mounted only on the SAM3X-EK evaluation kit.
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23.3 Block Diagram
Figure 23-1. Organization of the External Bus Interface
External Memory Bus
D[15:0]
A[23:1]
MUX
Logic
NAND Flash
Controller
Chip Select
Assignor
Static
Memory
Controller
SDRAM
Controller
Bus
Matrix
AHB
Address Decoder
A16/BA0
A0/NBS0
A17/BA1
NCS0
NCS3
NRD
NCS1
NCS2
NWR0/NWE
NWR1/NBS1
SDCKE
RAS
CAS
SDWE
NCS4
NCS5
NCS6
NCS7
NANDOE
NANDRDY
NANDWE
NWAIT
SDA10
PIO
SDCS
ECC
Controller
4K NFC
SRAM
A22/NANDCLE
A21/NANDALE
SDCK
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23.4 I/O Lines Description
The connection of some signals through the Mux logic is not direct and depends on the Memory Controller in use
at the moment.
Table 23-1. I/O Lines Description
Name Function Type Active Level
External Memory Bus
D[15:0] Data Bus I/O
A[23:0] Address Bus Output
Static Memory Controller (SMC)
NCS[7:0] Chip Select Lines Output Low
NWR0/NWE Write Signals Output Low
NRD Read Signal Output Low
NWR1/NBS1 Write Enable/Upper Byte Select Output Low
A0/NBS0 Lower Byte Select Output Low
NWAIT External Wait Signal Input Low
NAND Flash Controller (NFC)
NCS[7:0] Chip Select Lines Output Low
NANDOE NAND Flash Output Enable Output Low
NANDWE NAND Flash Write Enable Output Low
NANDCLE NAND Flash Command Line Enable Output Low
NANDALE NAND Flash Address Line Enable Output Low
NANDRDY NAND Flash Ready/Busy Input Low
SDR-SDRAM Controller
SDCK SDRAM Clock Output
SDCKE SDRAM Clock Enable Output High
SDCS SDRAM Controller Chip Select Line Output Low
BA[1:0] Bank Select Output
SDWE SDRAM Write Enable Output Low
RAS - CAS Row and Column Signal Output Low
NBS[1:0] Byte Mask Signals Output Low
SDA10 SDRAM Address 10 Line Output
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Table 23-2 details the connections between the two memory controllers and the bus pins.
23.5 Application Example
23.5.1 Hardware Interface
Table 23-3 details the connections to be applied between the External Memory Bus pins and the external devices
for each memory controller.
Table 23-2. External Memory Bus Pins and Memory Controllers I/O Lines Connections
EBI Pins SDRAMC I/O Lines SMC I/O Lines
NWR1/NBS1 NBS1 NWR1/NBS1
A0/NBS0 Not Supported A0/NBS0
A1 Not Supported A1
A[11:2] A[9:0] A[11:2]
SDA10 A10 Not Supported
A12 Not Supported A12
A[14:13] A[12:11] A[14:13]
A[23:15] Not Supported A[23:15]
D[15:0] D[15:0] D[15:0]
Table 23-3. EBI Pins and External Static Device Connections
EBI Pins
SMC Pins
SDR-SDRAMC
Pins
8-bit
Static Device 2 x 8-bit
Static Devices 16-bit
Static Device NAND Flash
D0–D7 D0–D7 D0–D7 D0–D7 I/O0–I/O7 D0–D7
D8–D15 – D8–D15 D8–D15 I/O8–I/O15(1) D8–D15
A0/NBS0 A0 – NLB – DQM0
A1 A1 A0 A0 – –
A2–A9 A2–A9 A1–A8 A1–A8 – A0–A7
A10 A10 A9 A9 – A8
A11 A11 A10 A10 – A9
SDCS ––––CS
SDA10 ––––A10
A12 A12 A11 A11 – –
A13–A14 A13–A14 A12–A13 A12–A13 – A11–A12
A15 A15 A14 A14 – –
A16/BA0 A16 A15 A15 – BA0
A17/BA1 A17 A16 A16 – BA1
A18–A20 A18–A20 A17–A19 A17–A19 – –
A21/NANDALE A21 A20 A20 ALE –
A22/NANDCLE A22 A21 A21 CLE –
A23 A23 A22 A22 – –
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Notes: 1. I/O8–I/O15 bits used only for 16-bit NAND Flash.
2. NWR1 enables upper byte writes. NWR0 enables lower byte writes.
3. CE connection depends on the NAND Flash.
For standard NAND Flash devices, it must be connected to any free PIO line.
For “CE don’t care” 8-bit NAND Flash devices, it can be either connected to any NCS
For “CE don’t care” 16-bit NAND Flash devices, it must be connected to any free PIO line.
23.6 Product Dependencies
23.6.1 I/O Lines
The pins used for interfacing the External Bus Interface may be multiplexed with the PIO lines. The programmer
must first program the PIO controller to assign the External Bus Interface pins to their peripheral function. If I/O
lines of the External Bus Interface are not used by the application, they can be used for other purposes by the PIO
Controller.
NCS0 CS CS CS CE(3) –
NCS1 CS CS CS – CS
NCS2 CS CS CS CE(3) –
NCS3 CS CS CS CE(3) –
NCS4 CS CS CS CE(3) –
NCS5 CS CS CS CE(3) –
NCS6 CS CS CS CE(3) –
NCS7 CS CS CS CE(3) –
NANDOE – – – RE –
NANDWE – – – WE –
NRD OEOEOE –
NWR0/NWE WE WE(2) WE –
NWR1/NBS1 WE WE(2) NUB – DQM1
SDCK ––––CLK
SDCKE ––––CKE
RAS ––––RAS
CAS ––––CAS
SDWE ––––WE
NWAIT –––––
NANDRDY – – – RDY –
Table 23-3. EBI Pins and External Static Device Connections (Continued)
EBI Pins
SMC Pins
SDR-SDRAMC
Pins
8-bit
Static Device 2 x 8-bit
Static Devices 16-bit
Static Device NAND Flash
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23.7 Functional Description
The external memory bus transfers data between the internal AHB Bus (handled by the memory controllers) and
the external memories or peripheral devices. It controls the waveforms and the parameters of the external
address, data and control buses and is composed of the following elements:
Static Memory Controller (SMC)
NAND Flash Controller (NFC)
SDRAM Controller (SDRAMC)
ECC Controller (ECC)
23.7.1 Bus Multiplexing
The external memory bus offers a complete set of control signals that share the 16-bit data lines, the address lines
of up to 24 bits and the control signals through a multiplex logic operating in function of the memory area requests.
Multiplexing is specifically organized in order to guarantee the maintenance of the address and output control lines
at a stable state while no external access is being performed. Multiplexing is also designed to respect the data float
times defined in the Memory Controllers. Furthermore, refresh cycles of the SDRAM are executed independently
by the SDRAM Controller without delaying the other external Memory Controller accesses.
23.7.2 Static Memory Controller
For information on the Static Memory Controller, refer to Section 25. “Static Memory Controller (SMC)”.
23.7.3 NAND Flash Controller
For information on the NAND Flash Controller, refer to Section 25. “Static Memory Controller (SMC)”.
23.7.4 SDRAM Controller
For information on the SDRAM Controller, refer to Section 24. “AHB SDRAM Controller (SDRAMC)”.
23.7.5 ECC Controller
For information on the ECC Controller, refer to Section 25. “Static Memory Controller (SMC)”.
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23.8 Implementation Examples
23.8.1 SDR-SDRAM
23.8.1.1 Software Configuration (2 x 8-bit SDR-SDRAM)
The following configuration must be respected:
Address lines A[2..11], A[13], BA0, BA1, SDA10, SDCS, SDWE, SDCKE, NBS1, RAS, CAS, and data lines
D[0..15] are multiplexed with PIO lines and thus dedicated PIOs must be programmed in peripheral mode in
the PIO controller.
Initialize the SDRAM Controller depending on the SDRAM device and system bus frequency.
The SDRAM initialization sequence is described in Section 24.5.1 “SDRAM Device Initialization”.
Figure 23-2. 2 x 8-bit SDR-SDRAM Hardware Configuration
SDRAM
Controller
D0-D15
RAS
CAS
SDCK
SDCKE
SDWE
NBS0
2M x 8
SDRAM
D0-D7
A0-A9, A11
RAS
CAS
CLK
CKE
WE
DQM
CS
BA0
BA1
NBS1
SDCS
D0-D7 D8-D15
BA0
BA1
A10 SDA10
A[2-11 ], A13
A[2-11 ], A13
SDA10
A[2-11 ], A13
BA0
BA1
2M x 8
SDRAM
D0-D7
A0-A9, A11
RAS
CAS
CLK
CKE
WE
DQM
CS
BA0
BA1
A10 BA0
BA1
NBS0NBS1
SDWE
SDWE
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23.8.1.2 Software Configuration (1 x 16-bit SDR-SDRAM)
The following configuration must be respected:
Address lines A[2..11], A[13-14], BA0, BA1, SDA10, SDCS, SDWE, SDCKE, NBS1, RAS, CAS, and data
lines D[0..15] are multiplexed with PIO lines and thus dedicated PIOs must be programmed in peripheral
mode in the PIO controller.
Initialize the SDRAM Controller depending on the SDRAM device and system bus frequency.
The SDRAM initialization sequence is described in Section 24.5.1 “SDRAM Device Initialization”.
Figure 23-3. 1 x 16-bit SDR-SDRAM Hardware Configuration
SDRAM
Controller
D0-D15 D0-D15
RAS
CAS
SDCK
SDCKE
SDWE
NBS0
16M x 16
A0-A9
RAS
CAS
CLK
CKE
WE
DQMH
DQML
CS
NBS1
SDCS
BA0
BA1
BA0
BA1
A10
A11 A13
A12 A14
SDA10
A13
A14
SDA10
A[2-11 ]
A[2-11]
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23.8.2 8-bit and 16-bit NAND Flash
23.8.2.1 Software Configuration (8-bit and 16-bit NAND Flash)
The following configuration must be respected:
NADNCLE, NANDALE, NANDOE, NANDRDY and NANDWE signals are multiplexed with PIO lines and
thus the dedicated PIOs must be programmed in peripheral mode in the PIO controller. D[0:7] or D[0:15]
must be programmed in peripheral mode in the PIO controller.
Assign the SMC chip select line CSx to the NAND Flash by setting the CSID field in the NFCADDR_CMD
Register.
Configure Static Memory Controller CSx Setup, Pulse, Cycle and Mode according to NAND Flash timings,
the data bus width and the system bus frequency.
Figure 23-4. 8-bit and 16-bit NAND Flash Hardware Configuration
D6
D0
D3
D4
D2
D1
D5
D7
WE
CE
RE
R/B
I/O0
ALE
CLE
I/O1
I/O3
I/O2
I/O7
I/O6
I/O5
I/O4
D6
D0
D3
D4
D2
D1
D5
D7
I/O0
I/O1
I/O3
I/O2
I/O7
I/O6
I/O5
I/O4
NCSx
NANDRDY
8-bit NAND
D14
D8
D11
D12
D10
D9
D13
D15
WE
CE
RE
R/B
I/O8
ALE
CLE
I/O9
I/O11
I/O10
I/O15
I/O14
I/O13
I/O12
16-bit NAND
NANDWE
NANDOE
NANDALE
NANDCLE
D[0:15]
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23.8.3 NOR Flash on NCS0
23.8.3.1 Software Configuration (NOR Flash on NCS0)
Address lines A[1..22], NCS0, NRD, NWE and data lines D[0..15] are multiplexed with PIO lines and thus
dedicated PIOs must be programmed in peripheral mode in the PIO controller.
The default configuration for the Static Memory Controller, byte select mode, 16-bit data bus, Read/Write
controlled by Chip Select, allows access on 16-bit non-volatile memory at slow clock.
For another configuration, configure the Static Memory Controller CS0 Setup, Pulse, Cycle and Mode depending
on Flash timings and system bus frequency.
Figure 23-5. NOR Flash on NCS0 Hardware Configuration
A21
A22
A1
A2
A3
A4
A5
A6
A7
A8
A15
A9
A12
A13
A11
A10
A14
A16
D6
D0
D3
D4
D2
D1
D5
D7
D14
D8
D11
D12
D10
D9
D13
D15
A17
A20
A18
A19
D[0..15]
A[1..22]
NRST
NWE
NCS0
NRD
3V3
3V3
TSOP48 PACKAGE
C2
100NF
C2
100NF
C1
100NF
C1
100NF
AT49BV6416
U1
AT49BV6416
U1
A0
25
A1
24
A2
23
A3
22
A4
21
A5
20
A6
19
A7
18
A8
8
A9
7
A10
6
A11
5
A12
4
A13
3
A14
2
A15
1
A16
48
A17
17
A18
16
A21
9A20
10 A19
15
WE
11 RESET
12
WP
14
OE
28 CE
26 VPP
13
DQ0 29
DQ1 31
DQ2 33
DQ3 35
DQ4 38
DQ5 40
DQ6 42
DQ7 44
DQ8 30
DQ9 32
DQ10 34
DQ11 36
DQ12 39
DQ13 41
DQ14 43
DQ15 45
VCCQ 47
VSS 27
VSS 46
VCC 37
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24. AHB SDRAM Controller (SDRAMC)
24.1 Description
The SDRAM Controller (SDRAMC) extends the memory capabilities of a chip by providing the interface to an
external 16-bit DRAM device. The page size supports ranges from 2048 to 8192 and the number of columns from
256 to 2048. It supports byte (8-bit), half-word (16-bit) and word (32-bit) accesses.
The SDRAM Controller supports a read or write burst length of one location. It keeps track of the active row in each
bank, thus maximizing SDRAM performance, e.g., the application may be placed in one bank and data in the other
banks. So as to optimize performance, it is advisable to avoid accessing different rows in the same bank.
The SDRAM controller supports a CAS latency of 1, 2 or 3 and optimizes the read access depending on the
frequency.
The different modes available - self-refresh, power-down and deep power-down modes - minimize power
consumption on the SDRAM device.
24.2 Embedded Characteristics
Numerous Configurations Supported
̶2K, 4K, 8K Row Address Memory Parts
̶SDRAM with Two or Four Internal Banks
̶SDRAM with 16-bit Data Path
Programming Facilities
̶Word, Half-word, Byte Access
̶Automatic Page Break When Memory Boundary Has Been Reached
̶Multibank Ping-pong Access
̶Timing Parameters Specified by Software
̶Automatic Refresh Operation, Refresh Rate is Programmable
̶Automatic Update of DS, TCR and PASR Parameters (Mobile SDRAM Devices)
Energy-saving Capabilities
̶Self-refresh, Power-down and Deep Power Modes Supported
̶Supports Mobile SDRAM Devices
Error Detection
̶Refresh Error Interrupt
SDRAM Power-up Initialization by Software
CAS Latency of 1, 2, 3 Supported
Auto Precharge Command Not Used
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24.3 I/O Lines Description
Table 24-1. I/O Line Description
Name Description Type Active Level
SDCK SDRAM Clock Output
SDCKE SDRAM Clock Enable Output High
SDCS SDRAM Controller Chip Select Output Low
BA[1:0] Bank Select Signals Output
RAS Row Signal Output Low
CAS Column Signal Output Low
SDWE SDRAM Write Enable Output Low
NBS[3:0] Data Mask Enable Signals Output Low
SDRAMC_A[12:0] Address Bus Output
D[15:0] Data Bus I/O
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24.4 Application Example
24.4.1 Software Interface
The SDRAM address space is organized into banks, rows, and columns. The SDRAM controller allows mapping
different memory types according to the values set in the SDRAMC configuration register.
The SDRAM Controller’s function is to make the SDRAM device access protocol transparent to the user. Table 24-
2 to Table 24-4 illustrate the SDRAM device memory mapping seen by the user in correlation with the device
structure. Various configurations are illustrated.
24.4.1.1 16-bit Memory Data Bus Width
Notes: 1. M0 is the byte address inside a 16-bit half-word.
2. Bk[1] = BA1, Bk[0] = BA0.
Table 24-2. SDRAM Configuration Mapping: 2K Rows, 256/512/1024/2048 Columns
CPU Address Line
27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Bk[1:0] Row[10:0] Column[7:0] M0
Bk[1:0] Row[10:0] Column[8:0] M0
Bk[1:0] Row[10:0] Column[9:0] M0
Bk[1:0] Row[10:0] Column[10:0] M0
Table 24-3. SDRAM Configuration Mapping: 4K Rows, 256/512/1024/2048 Columns
CPU Address Line
27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Bk[1:0] Row[11:0] Column[7:0] M0
Bk[1:0] Row[11:0] Column[8:0] M0
Bk[1:0] Row[11:0] Column[9:0] M0
Bk[1:0] Row[11:0] Column[10:0] M0
Table 24-4. SDRAM Configuration Mapping: 8K Rows, 256/512/1024/2048 Columns
CPU Address Line
27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Bk[1:0] Row[12:0] Column[7:0] M0
Bk[1:0] Row[12:0] Column[8:0] M0
Bk[1:0] Row[12:0] Column[9:0] M0
Bk[1:0] Row[12:0] Column[10:0] M0
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24.5 Product Dependencies
24.5.1 SDRAM Device Initialization
The initialization sequence is generated by software. The SDRAM devices are initialized by the following
sequence:
1. SDRAM features must be set in the configuration register: asynchronous timings (TRC, TRAS, etc.), num-
ber of columns, rows, CAS latency, and the data bus width.
2. For mobile SDRAM, temperature-compensated self refresh (TCSR), drive strength (DS) and partial array
self refresh (PASR) must be set in the Low Power Register.
3. The SDRAM memory type must be set in the Memory Device Register.
4. A minimum pause of 200 µs is provided to precede any signal toggle.
5. (1)A NOP command is issued to the SDRAM devices. The application must set Mode to 1 in the Mode
Register and perform a write access to any SDRAM address.
6. An All Banks Precharge command is issued to the SDRAM devices. The application must set Mode to 2 in
the Mode Register and perform a write access to any SDRAM address.
7. Eight auto-refresh (CBR) cycles are provided. The application must set the Mode to 4 in the Mode Register
and perform a write access to any SDRAM location eight times.
8. A Mode Register set (MRS) cycle is issued to program the parameters of the SDRAM devices, in particular
CAS latency and burst length. The application must set Mode to 3 in the Mode Register and perform a write
access to the SDRAM. The write address must be chosen so that BA[1:0] are set to 0. For example, with a
16-bit 128 MB SDRAM (12 rows, 9 columns, 4 banks) bank address, the SDRAM write access should be
done at the address 0x70000000.
9. For mobile SDRAM initialization, an Extended Mode Register set (EMRS) cycle is issued to program the
SDRAM parameters (TCSR, PASR, DS). The application must set Mode to 5 in the Mode Register and
perform a write access to the SDRAM. The write address must be chosen so that BA[1] or BA[0] are set to 1.
For example, with a 16-bit 128 MB SDRAM, (12 rows, 9 columns, 4 banks) bank address the SDRAM write
access should be done at the address 0x70800000 or 0x70400000.
10. The application must go into Normal Mode, setting Mode to 0 in the Mode Register and performing a write
access at any location in the SDRAM.
11. Write the refresh rate into the count field in the SDRAMC Refresh Timer register. (Refresh rate = delay
between refresh cycles). The SDRAM device requires a refresh every 15.625 µs or 7.81 µs. With a 100 MHz
frequency, the Refresh Timer Counter Register must be set with the value 1562(15.625 µs x 100 MHz) or
781(7.81 µs x 100 MHz).
After initialization, the SDRAM devices are fully functional.
Note: 1. It is strongly recommended to respect the instructions stated in Step 5 of the initialization process in order to be
certain that the subsequent commands issued by the SDRAMC will be taken into account.
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Figure 24-1. SDRAM Device Initialization Sequence
24.5.2 I/O Lines
The pins used for interfacing the SDRAM Controller may be multiplexed with the PIO lines. The programmer must
first program the PIO controller to assign the SDRAM Controller pins to their peripheral function. If I/O lines of the
SDRAM Controller are not used by the application, they can be used for other purposes by the PIO Controller.
24.5.3 Interrupt
The SDRAM Controller interrupt (Refresh Error notification) is connected to the Memory Controller.
Using the SDRAM Controller interrupt requires the Interrupt Controller to be programmed first.
SDCK
SDRAMC_A[9:0]
A10
SDRAMC_A[12:11]
SDCS
RAS
CAS
SDWE
NBS
Inputs Stable for
200 μsec Precharge All Banks1st Auto-refresh8th Auto-refresh MRS Command Valid Command
SDCKE tRP tRC tMRD
Table 24-5. Peripheral IDs
Instance ID
SDRAMC 10
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24.5.4 Power Management
The SDRAM Controller may be clocked through the Power Management Controller (PMC), thus the programmer
must first configure the PMC to enable the SDRAM Controller clock. The SDRAM Controller Clock (not the SDCK
pin) is managed by the Static Memory Controller Clock.
The SDRAM Clock on SDCK pin will be output as soon as the first access to the SDRAM is done during the
initialization phase.
If one needs to stop the SDRAM clock signal, the Low Power Mode Register (SDRAMC_LPR) must be
programmed with the sefl-refresh command.
W X§Xa§XXXXXXXXXXX>C m ; fl r % r ‘ D?XXXXXXXXXXX>— AtmeL
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24.6 Functional Description
24.6.1 SDRAM Controller Write Cycle
The SDRAM Controller allows burst access or single access. In both cases, the SDRAM controller keeps track of
the active row in each bank, thus maximizing performance. To initiate a burst access, the SDRAM Controller uses
the transfer type signal provided by the master requesting the access. If the next access is a sequential write
access, writing to the SDRAM device is carried out. If the next access is a write-sequential access, but the current
access is to a boundary page, or if the next access is in another row, then the SDRAM Controller generates a
precharge command, activates the new row and initiates a write command. To comply with SDRAM timing
parameters, additional clock cycles are inserted between precharge/active (tRP) commands and active/write (tRCD)
commands. For definition of these timing parameters, refer to the “SDRAMC Configuration Register” on page 408.
This is described in Figure 24-2 below.
Figure 24-2. Write Burst SDRAM Access
SDCK
SDCS
RAS
CAS
SDRAMC_A[12:0]
DATA
t
RCD
= 3
Dna
SDWE
DnbDnc Dnd Dne Dnf Dng Dnh Dni Dnj Dnk Dnl
Row n col acol bcol c col d col e col f col g col h col i col j col k col l
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24.6.2 SDRAM Controller Read Cycle
The SDRAM Controller allows burst access, incremental burst of unspecified length or single access. In all cases,
the SDRAM Controller keeps track of the active row in each bank, thus maximizing performance of the SDRAM. If
row and bank addresses do not match the previous row/bank address, then the SDRAM controller automatically
generates a precharge command, activates the new row and starts the read command. To comply with the
SDRAM timing parameters, additional clock cycles on SDCK are inserted between precharge and active
commands (tRP) and between active and read command (tRCD). These two parameters are set in the configuration
register of the SDRAM Controller. After a read command, additional wait states are generated to comply with the
CAS latency (1, 2 or 3 clock delays specified in the configuration register).
For a single access or an incremented burst of unspecified length, the SDRAM Controller anticipates the next
access. While the last value of the column is returned by the SDRAM Controller on the bus, the SDRAM Controller
anticipates the read to the next column and thus anticipates the CAS latency. This reduces the effect of the CAS
latency on the internal bus.
For burst access of specified length (4, 8, 16 words), access is not anticipated. This case leads to the best
performance. If the burst is broken (border, busy mode, etc.), the next access is handled as an incrementing burst
of unspecified length.
Figure 24-3. Read Burst SDRAM Access
SDCK
SDCS
RAS
CAS
SDRAMC_A[12:0]
DATA
(Input)
t
RCD
= 3
Dna
SDWE
DnbDnc Dnd Dne Dnf
Row n col acol bcol c col d col e col f
CAS = 2
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24.6.3 Border Management
When the memory row boundary has been reached, an automatic page break is inserted. In this case, the SDRAM
controller generates a precharge command, activates the new row and initiates a read or write command. To
comply with SDRAM timing parameters, an additional clock cycle is inserted between the precharge/active (tRP)
command and the active/read (tRCD) command. This is described in Figure 24-4 below.
Figure 24-4. Read Burst with Boundary Row Access
SDCK
SDCS
RAS
CAS
SDRAMC_A[12:0]
DATA
T
RP
= 3
SDWE
Row m
col acol acol bcol c col d col e
DnaDnbDnc Dnd
T
RCD
= 3 CAS = 2
col bcol c col d
DmaDmbDmc Dmd
Row n
Dme
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24.6.4 SDRAM Controller Refresh Cycles
An auto-refresh command is used to refresh the SDRAM device. Refresh addresses are generated internally by
the SDRAM device and incremented after each auto-refresh automatically. The SDRAM Controller generates
these auto-refresh commands periodically. An internal timer is loaded with the value in the register SDRAMC_TR
that indicates the number of clock cycles between refresh cycles.
A refresh error interrupt is generated when the previous auto-refresh command did not perform. It is acknowledged
by reading the Interrupt Status Register (SDRAMC_ISR).
When the SDRAM Controller initiates a refresh of the SDRAM device, internal memory accesses are not delayed.
However, if the CPU tries to access the SDRAM, the slave indicates that the device is busy and the master is held
by a wait signal. See Figure 24-5.
Figure 24-5. Refresh Cycle Followed by a Read Access
24.6.5 Power Management
Three low-power modes are available:
Self-refresh Mode: The SDRAM executes its own Auto-refresh cycle without control of the SDRAM
Controller. Current drained by the SDRAM is very low.
Power-down Mode: Auto-refresh cycles are controlled by the SDRAM Controller. Between auto-refresh
cycles, the SDRAM is in power-down. Current drained in Power-down mode is higher than in Self-refresh
Mode.
Deep Power-down Mode: (Only available with Mobile SDRAM) The SDRAM contents are lost, but the
SDRAM does not drain any current.
The SDRAM Controller activates one low-power mode as soon as the SDRAM device is not selected. It is possible
to delay the entry in self-refresh and power-down mode after the last access by programming a timeout value in
the Low Power Register.
SDCK
SDCS
RAS
CAS
SDRAMC_A[12:0]
DATA
(input)
t
RP
= 3
SDWE
DnbDnc Dnd
col c col d
CAS = 2
Row m col a
t
RC
= 8 t
RCD
= 3
Dma
Row n
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24.6.5.1 Self-refresh Mode
This mode is selected by programming the LPCB field to 1 in the SDRAMC Low Power Register. In self-refresh
mode, the SDRAM device retains data without external clocking and provides its own internal clocking, thus
performing its own auto-refresh cycles. All the inputs to the SDRAM device become “don’t care” except SDCKE,
which remains low. As soon as the SDRAM device is selected, the SDRAM Controller provides a sequence of
commands and exits self-refresh mode.
Some low-power SDRAMs (e.g., mobile SDRAM) can refresh only one quarter or a half quarter or all banks of the
SDRAM array. This feature reduces the self-refresh current. To configure this feature, Temperature Compensated
Self Refresh (TCSR), Partial Array Self Refresh (PASR) and Drive Strength (DS) parameters must be set in the
Low Power Register and transmitted to the low-power SDRAM during initialization.
After initialization, as soon as PASR/DS/TCSR fields are modified and self-refresh mode is activated, the
Extended Mode Register is accessed automatically and PASR/DS/TCSR bits are updated before entry into self-
refresh mode. This feature is not supported when SDRAMC shares an external bus with another controller.
The SDRAM device must remain in self-refresh mode for a minimum period of tRAS and may remain in self-refresh
mode for an indefinite period. This is described in Figure 24-6.
Figure 24-6. Self-refresh Mode Behavior
SDCK
SDCS
RAS
CAS
S
DRAMC_A[12:0]
Self Refresh Mode
SDWE
Row
T
XSR
= 3
SDCKE
Write
SDRAMC_SRR
SRCB = 1
Access Request
to the SDRAM Controller
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24.6.5.2 Low-power Mode
This mode is selected by programming the LPCB field to 2 in the SDRAMC Low Power Register. Power
consumption is greater than in self-refresh mode. All the input and output buffers of the SDRAM device are
deactivated except SDCKE, which remains low. In contrast to self-refresh mode, the SDRAM device cannot
remain in low-power mode longer than the refresh period (64 ms for a whole device refresh operation). As no auto-
refresh operations are performed by the SDRAM itself, the SDRAM Controller carries out the refresh operation.
The exit procedure is faster than in self-refresh mode.
This is described in Figure 24-7.
Figure 24-7. Low-power Mode Behavior
SDCK
SDCS
RAS
CAS
SDRAMC_A[12:0]
DATA
(input)
T
RCD
= 3
DnaDnbDnc Dnd Dne Dnf
Row n col acol bcol c col d col e col f
CAS = 2
SDCKE
Low Power Mode
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24.6.5.3 Deep Power-down Mode
This mode is selected by programming the LPCB field to 3 in the SDRAMC Low Power Register. When this mode
is activated, all internal voltage generators inside the SDRAM are stopped and all data is lost.
When this mode is enabled, the application must not access to the SDRAM until a new initialization sequence is
done (See “SDRAM Device Initialization” on page 395).
This is described in Figure 24-8.
Figure 24-8. Deep Power-down Mode Behavior
SDCK
SDCS
RAS
CAS
SDRAMC_A[12:0]
DATA
(input)
t
RP
= 3
SDWE
DnbDnc Dnd
col c col d
Row n
CKE
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24.7 AHB SDRAM Controller (SDRAMC) User Interface
Table 24-6. Register Mapping
Offset Register Name Access Reset
0x00 SDRAMC Mode Register SDRAMC_MR Read-write 0x00000000
0x04 SDRAMC Refresh Timer Register SDRAMC_TR Read-write 0x00000000
0x08 SDRAMC Configuration Register SDRAMC_CR Read-write 0x852372C0
0x10 SDRAMC Low Power Register SDRAMC_LPR Read-write 0x0
0x14 SDRAMC Interrupt Enable Register SDRAMC_IER Write-only –
0x18 SDRAMC Interrupt Disable Register SDRAMC_IDR Write-only –
0x1C SDRAMC Interrupt Mask Register SDRAMC_IMR Read-only 0x0
0x20 SDRAMC Interrupt Status Register SDRAMC_ISR Read-only 0x0
0x24 SDRAMC Memory Device Register SDRAMC_MDR Read-write 0x0
0x28 SDRAMC Configuration Register 1 SDRAMC_CR1 Read-write 0x02
0x2C SDRAMC OCMS Register 1 SDRAMC_OCMS Read-write 0x0000000
0x30 - 0xF8 Reserved – – –
0x28 - 0xFC Reserved – – –
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24.7.1 SDRAMC Mode Register
Name: SDRAMC_MR
Address: 0x400E0200
Access: Read-write
Reset: 0x00000000
• MODE: SDRAMC Command Mode
This field defines the command issued by the SDRAM Controller when the SDRAM device is accessed.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––– MODE
Value Name Description
000 NORMAL Normal mode. Any access to the SDRAM is decoded normally. To activate this mode,
command must be followed by a write to the SDRAM.
001 NOP The SDRAM Controller issues a NOP command when the SDRAM device is accessed
regardless of the cycle. To activate this mode, command must be followed by a write to
the SDRAM.
010 ALLBANKS_PRECHARGE The SDRAM Controller issues an “All Banks Precharge” command when the SDRAM
device is accessed regardless of the cycle. To activate this mode, command must be
followed by a write to the SDRAM.
011 LOAD_MODEREG The SDRAM Controller issues a “Load Mode Register” command when the SDRAM
device is accessed regardless of the cycle. To activate this mode, command must be
followed by a write to the SDRAM.
100 AUTO_REFRESH The SDRAM Controller issues an “Auto-Refresh” Command when the SDRAM device is
accessed regardless of the cycle. Previously, an “All Banks Precharge” command must
be issued. To activate this mode, command must be followed by a write to the SDRAM.
101 EXT_LOAD_MODEREG
The SDRAM Controller issues an “Extended Load Mode Register” command when the
SDRAM device is accessed regardless of the cycle. To activate this mode, the “Extended
Load Mode Register” command must be followed by a write to the SDRAM. The write in
the SDRAM must be done in the appropriate bank; most low-power SDRAM devices use
the bank 1.
110 DEEP_POWERDOWN Deep power-down mode. Enters deep power-down mode.
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24.7.2 SDRAMC Refresh Timer Register
Name: SDRAMC_TR
Address: 0x400E0204
Access: Read-write
Reset: 0x00000000
• COUNT: SDRAMC Refresh Timer Count
This 12-bit field is loaded into a timer that generates the refresh pulse. Each time the refresh pulse is generated, a refresh
burst is initiated. The SDRAM device requires a refresh every 15.625 µs or 7.81 µs. With a 100 MHz frequency, the
Refresh Timer Counter Register must be set with the value 1562 (15.625 µs x 100 MHz) or 781 (7.81 µs x 100 MHz).
To refresh the SDRAM device, this 12-bit field must be written. If this condition is not satisfied, no refresh command is
issued and no refresh of the SDRAM device is carried out.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––– COUNT
76543210
COUNT
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24.7.3 SDRAMC Configuration Register
Name: SDRAMC_CR
Address: 0x400E0208
Access: Read-write
Reset: 0x852372C0
Warning: bit 7 (DBW) must always be set to 1 when programming the SDRAMC_CR register.
• NC: Number of Column Bits
Reset value is 8 column bits.
• NR: Number of Row Bits
Reset value is 11 row bits.
Values which are not listed in the table must be considered as “reserved”.
• NB: Number of Banks
Reset value is two banks.
31 30 29 28 27 26 25 24
TXSR TRAS
23 22 21 20 19 18 17 16
TRCD TRP
15 14 13 12 11 10 9 8
TRC_TRFC TWR
76543210
DBW CAS NB NR NC
Value Name Description
00 COL8 8 column bits
01 COL9 9 column bits
10 COL10 10 column bits
11 COL11 11 column bits
Value Name Description
00 ROW11 11 row bits
01 ROW12 12 row bits
10 ROW13 13 row bits
Value Name Description
0 BANK2 2 banks
1 BANK4 4 banks
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• CAS: CAS Latency
Reset value is two cycles.
In the SDRAMC, only a CAS latency of one, two and three cycles are managed.
Values which are not listed in the table must be considered as “reserved”.
• DBW: Data Bus Width
Reset value is 16 bits
This field defines the Data Bus Width, which is 16 bits. It must be set to 1.
• TWR: Write Recovery Delay
Reset value is two cycles.
This field defines the Write Recovery Time in number of cycles. Number of cycles is between 0 and 15.
• TRC_TRFC: Row Cycle Delay and Row Refresh Cycle
Reset value is seven cycles.
This field defines two timings:
the delay (tRFC) between two Refresh commands,
the delay (tRFC) between Refresh command and an Activate command
and the delay (tRC) between two Active commands in number of cycles.
The number of cycles is between 0 and 15. The end user will have to program max {tRC, tRFC}.
• TRP: Row Precharge Delay
Reset value is three cycles.
This field defines the delay between a Precharge Command and another Command in number of cycles. Number of cycles
is between 0 and 15.
• TRCD: Row to Column Delay
Reset value is two cycles.
This field defines the delay between an Activate Command and a Read/Write Command in number of cycles. Number of
cycles is between 0 and 15.
• TRAS: Active to Precharge Delay
Reset value is five cycles.
This field defines the delay between an Activate Command and a Precharge Command in number of cycles. Number of
cycles is between 0 and 15.
• TXSR: Exit Self Refresh to Active Delay
Reset value is eight cycles.
This field defines the delay between SCKE set high and an Activate Command in number of cycles. Number of cycles is
between 0 and 15.
Value Name Description
01 LATENCY1 1 cycle CAS latency
10 LATENCY2 2 cycle CAS latency
11 LATENCY3 3 cycle CAS latency
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24.7.4 SDRAMC Low Power Register
Name: SDRAMC_LPR
Address: 0x400E0210
Access: Read-write
Reset: 0x0
• LPCB: Low-power Configuration Bits
• PASR: Partial Array Self-refresh (only for low-power SDRAM)
PASR parameter is transmitted to the SDRAM during initialization to specify whether only one quarter, one half or all banks
of the SDRAM array are enabled. Disabled banks are not refreshed in self-refresh mode. This parameter must be set
according to the SDRAM device specification.
After initialization, as soon as PASR field is modified and self-refresh mode is activated, the Extended Mode Register is
accessed automatically and PASR bits are updated before entry in self-refresh mode.This feature is not supported when
SDRAMC shares an external bus with another controller.
• TCSR: Temperature Compensated Self-Refresh (only for low-power SDRAM)
TCSR parameter is transmitted to the SDRAM during initialization to set the refresh interval during self-refresh mode
depending on the temperature of the low-power SDRAM. This parameter must be set according to the SDRAM device
specification.
After initialization, as soon as TCSR field is modified and self-refresh mode is activated, the Extended Mode Register is
accessed automatically and TCSR bits are updated before entry in self-refresh mode.This feature is not supported when
SDRAMC shares an external bus with another controller.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–– TIMEOUT DS TCSR
76543210
– PASR – – LPCB
Value Name Description
00 DISABLED Low Power Feature is inhibited: no Power-down, Self-refresh or Deep Power-down
command is issued to the SDRAM device.
01 SELF_REFRESH The SDRAM Controller issues a Self-refresh command to the SDRAM device, the
SDCK clock is deactivated and the SDCKE signal is set low. The SDRAM device leaves
the Self Refresh Mode when accessed and enters it after the access.
10 POWER_DOWN The SDRAM Controller issues a Power-down Command to the SDRAM device after
each access, the SDCKE signal is set to low. The SDRAM device leaves the Power-
down Mode when accessed and enters it after the access.
11 DEEP_POWER_DOWN The SDRAM Controller issues a Deep Power-down command to the SDRAM device.
This mode is unique to low-power SDRAM.
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• DS: Drive Strength (only for low-power SDRAM)
DS parameter is transmitted to the SDRAM during initialization to select the SDRAM strength of data output. This parame-
ter must be set according to the SDRAM device specification.
After initialization, as soon as DS field is modified and self-refresh mode is activated, the Extended Mode Register is
accessed automatically and DS bits are updated before entry in self-refresh mode. This feature is not supported when
SDRAMC shares an external bus with another controller.
• TIMEOUT: Time to define when low-power mode is enable
Values which are not listed in the table must be considered as “reserved”.
Value Name Description
00 LP_LAST_XFER The SDRAM controller activates the SDRAM low-power mode immediately after the end
of the last transfer.
01 LP_LAST_XFER_64 The SDRAM controller activates the SDRAM low-power mode 64 clock cycles after the
end of the last transfer.
10 LP_LAST_XFER_128 The SDRAM controller activates the SDRAM low-power mode 128 clock cycles after the
end of the last transfer.
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24.7.5 SDRAMC Interrupt Enable Register
Name: SDRAMC_IER
Address: 0x400E0214
Access: Write-only
• RES: Refresh Error Status
0: No effect.
1: Enables the refresh error interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––RES
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24.7.6 SDRAMC Interrupt Disable Register
Name: SDRAMC_IDR
Address: 0x400E0218
Access: Write-only
• RES: Refresh Error Status
0: No effect.
1: Disables the refresh error interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––RES
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24.7.7 SDRAMC Interrupt Mask Register
Name: SDRAMC_IMR
Address: 0x400E021C
Access: Read-only
• RES: Refresh Error Status
0: The refresh error interrupt is disabled.
1: The refresh error interrupt is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––RES
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24.7.8 SDRAMC Interrupt Status Register
Name: SDRAMC_ISR
Address: 0x400E0220
Access: Read-only
• RES: Refresh Error Status
0: No refresh error has been detected since the register was last read.
1: A refresh error has been detected since the register was last read.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––RES
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24.7.9 SDRAMC Memory Device Register
Name: SDRAMC_MDR
Address: 0x400E0224
Access: Read-write
• MD: Memory Device Type
Values which are not listed in the table must be considered as “reserved”.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––– MD
Value Name Description
00 SDRAM SDRAM
01 LPSDRAM Low-power SDRAM
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24.7.10 SDRAMC Configuration 1 Register
Name: SDRAMC_CR1
Address: 0x400E0228
Access: Read-write
• TMRD: Load Mode Register Command to Active or Refresh Command
Reset Value is 2 cycles.
This field defines the delay between a Load mode register command and an active or refresh command in number of
cycles. Number of cycles is between 0 and 15.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––– TMRD
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24.7.11 SDRAMC OCMS Register
Name: SDRAMC_OCMS
Address: 0x400E022C
Access: Read-write
• SDR_SE: SDRAM Memory Controller Scrambling Enable
0: Disable “Off Chip” Scrambling for SDR-SDRAM access.
1: Enable “Off Chip” Scrambling for SDR-SDRAM access.
Before scrambling SDR-SDRAM access, the end user must set to 1 the bit field SMSE (Static Memory Controller Scram-
bling Enable) in the SMC_OCMS register, located in the Static Memory Controller block.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
SDR_SE
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25. Static Memory Controller (SMC)
25.1 Description
The External Bus Interface is designed to ensure the successful data transfer between several external devices
and the Cortex-M3 based device. The External Bus Interface of the SAM3X consists of a Static Memory Controller
(SMC).
This SMC is capable of handling several types of external memory and peripheral devices, such as SRAM,
PSRAM, PROM, EPROM, EEPROM, LCD Module, NOR Flash and NAND Flash.
The SMC generates the signals that control the access to external memory devices or peripheral devices. It has 8
Chip Selects and a 24-bit address bus. The 16-bit data bus can be configured to interface with 8- or 16-bit external
devices. Separate read and write control signals allow for direct memory and peripheral interfacing. Read and
write signal waveforms are fully parametrizable.
The SMC can manage wait requests from external devices to extend the current access. The SMC is provided with
an automatic slow clock mode. In slow clock mode, it switches from user-programmed waveforms to slow-rate
specific waveforms on read and write signals.
The SMC embeds a NAND Flash Controller (NFC). The NFC can handle automatic transfers, sending the
commands and address cycles to the NAND Flash and transferring the contents of the page (for read and write) to
the NFC SRAM. It minimizes the CPU overhead.
The SMC includes programmable hardware error correcting code with one bit error correction capability and
supports two bits error detection. In order to improve overall system performance the DATA phase of the transfer
can be DMA assisted.
The External Data Bus can be scrambled/unscrambled by means of user keys.
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25.2 Embedded Characteristics
16-Mbyte Address Space per Chip Select
8- or 16-bit Data Bus
Word, Halfword, Byte Transfers
Byte Write or Byte Select Lines
Programmable Setup, Pulse and Hold Time for Read Signals per Chip Select
Programmable Setup, Pulse and Hold Time for Write Signals per Chip Select
Programmable Data Float Time per Chip Select
External Data Bus Scrambling/Unscrambling Function
External Wait Request
Automatic Switch to Slow Clock Mode
NAND Flash Controller Supporting NAND Flash with Multiplexed Data/Address Buses
Supports SLC NAND Flash Technology
Hardware Configurable Number of Chip Selects from 1 to 8
Programmable Timing on a per Chip Select Basis
AHB Slave Interface
Atmel APB Configuration Interface
Programmable Flash Data Width 8 Bits or 16 Bits
Supports Hardware Error Correcting Code (ECC), 1-bit Error Correction, 2-bit Error Detection
Detection and Correction by Software
Supports NAND Flash and SmartMedia™ Devices with 8- or 16-bit Data Path
Supports NAND Flash/SmartMedia with Page Sizes of 528, 1056, 2112 and 4224 Bytes, Specified by
Software
Supports 1-bit Correction for a Page of 512, 1024, 2048 and 4096 Bytes with 8- or 16-bit Data Path
Supports 1-bit Correction per 512 Bytes of Data for a Page Size of 512, 2048 and 4096 Bytes with 8-bit Data
Path
Supports 1-bit Correction per 256 Bytes of Data for a Page Size of 512, 2048 and 4096 Bytes with 8-bit Data
Path
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25.3 Block Diagram
Figure 25-1. Block Diagram
25.4 I/O Lines Description
SMC
Interface
NANDRDY
D[15:0]
NFC
Internal SRAM
NAND Flash
Controller (NFC)
ECC
NWR0/NWE
NCS[3:0]
NWAIT
NANDOE
NANDWE
A23
NRD
A[0]/NBS0
A[20:1]
NWR1/NBS1
A21/NANDALE
A22/NANDCLE
Control & Status
Registers
SRAM
AHB
Interface
AHB
arbiter
Scrambler
SMC
AHB
Interface
(4 K bytes)
User Interface
Table 25-1. I/O Line Description
Name Description Type Active Level
NCS[3:0] Static Memory Controller Chip Select Lines Output Low
NRD Read Signal Output Low
NWR0/NWE Write 0/Write Enable Signal Output Low
A0/NBS0 Address Bit 0/Byte 0 Select Signal Output Low
NWR1/NBS1 Write 1/Byte 1 Select Signal Output Low
A1 Address Bit 1 Output Low
A[23:2] Address Bus Output
D[15:0] Data Bus I/O
NWAIT External Wait Signal Input Low
NANDRDY NAND Flash Ready/Busy Input
NANDWE NAND Flash Write Enable Output Low
NANDOE NAND Flash Output Enable Output Low
NANDALE NAND Flash Address Latch Enable Output
NANDCLE NAND Flash Command Latch Enable Output
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25.5 Multiplexed Signals
25.6 Application Example
25.6.1 Implementation Examples
For Hardware implementation examples, please refer to ATSAM3X-EK schematics which show examples of
connection to an LCD module, PSRAM and NAND Flash.
25.6.2 Hardware Interface
Figure 25-2. SMC Connections to Static Memory Devices
Table 25-2. Static Memory Controller (SMC) Multiplexed Signals
Multiplexed Signals Related Function
NWR0 NWE Byte-write or byte-select access, see Figure 25-4 "Memory Connection for an 8-bit Data
Bus" and Figure 25-5 "Memory Connection for a 16-bit Data Bus"
A0 NBS0 8-bit or 16-bit data bus, see Section 25.9.1 ”Data Bus Width”
A22 NANDCLE NAND Flash Command Latch Enable
A21 NANDALE NAND Flash Address Latch Enable
NWR1 NBS1 Byte-write or byte-select access, see Figure 25-4 and Figure 25-5
A1 – 8-/16-bit data bus, see Section 25.9.1 ”Data Bus Width”
Byte-write or byte-select access, see Figure 25-4 and Figure 25-5
Static Memory
Controller
D0-D15
A2 - A23
A0/NBS0
NWR0/NWE
NWR1/NBS1
A1
128K x 8
SRAM
D0 - D7
A0 - A16
OE
WE
CS
D0 - D7 D8-D15
A2 - A18
128K x 8
SRAM
D0-D7
CS
NWR1/NBS1
NRD
NWR0/NWE
NCS0
NCS1
NCS2
NCS3
NCS4
NCS5
NCS6
NCS7
NRD OE
WE
A2 - A18
A0 - A16
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25.7 Product Dependencies
25.7.1 I/O Lines
The pins used for interfacing the Static Memory Controller are multiplexed with the PIO lines. The programmer
must first program the PIO controller to assign the Static Memory Controller pins to their peripheral function. If I/O
Lines of the SMC are not used by the application, they can be used for other purposes by the PIO Controller.
25.7.2 Power Management
The SMC is clocked through the Power Management Controller (PMC), thus the programmer must first configure
the PMC to enable the SMC clock.
25.7.3 Interrupt
The SMC has an interrupt line connected to the Nested Vector Interrupt Controller (NVIC). Handling the SMC
interrupt requires programming the NVIC before configuring the SMC.
25.8 External Memory Mapping
Note: 1. See Section 25.16.2 ”NFC Control Registers”, i.e., CMD_ADDR description.
The SMC provides up to 24 address lines, A[23:0]. This allows each chip select line to address up to 16 Mbytes of
memory.
If the physical memory device connected on one chip select is smaller than 16 Mbytes, it wraps around and
appears to be repeated within this space. The SMC correctly handles any valid access to the memory device
within the page (see Figure 25-3).
A[23:0] is only significant for 8-bit memory, A[23:1] is used for 16-bit memory.
Table 25-3. Peripheral IDs
Instance ID
SMC 9
Table 25-4. External Memory Mapping
Address Use Access
0x60000000-0x60FFFFFF Chip Select 0 (16 MB) Read-write
0x61000000-0x61FFFFFF Chip Select 1 Read-write
0x62000000-0x62FFFFFF Chip Select 2 Read-write
0x63000000-0x63FFFFFF Chip Select 3 Read-write
0x64000000-0x64FFFFFF Chip Select 4 Read-write
0x65000000-0x65FFFFFF Chip Select 5 Read-write
0x66000000-0x66FFFFFF Chip Select 6 Read-write
0x67000000-0x67FFFFFF Chip Select 7 Read-write
0x68000000-0x6FFFFFFF NFC Command Registers(1) Read-write
Memory Enable Memory Enable Memory Enab‘e emery Enable y Enab‘e able AtmeL
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Figure 25-3. Memory Connections for External Devices
NRD
NWE
A[23:0]
D[15:0]
8 or 16
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Output Enable
Write Enable
A[25:0]
D[15:0] or D[7:0]
NCS3
NCS0
NCS1
NCS2
NCS7
NCS4
NCS5
NCS6
NCS[0] - NCS[7]
SMC
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25.9 Connection to External Devices
25.9.1 Data Bus Width
A data bus width of 8 or 16 bits can be selected for each chip select. This option is controlled by the field DBW in
SMC_MODE (Mode Register) for the corresponding chip select.
Figure 25-4 shows how to connect a 512K x 8-bit memory on NCS2. Figure 25-5 shows how to connect a 512K x
16-bit memory on NCS2.
25.9.2 Byte Write or Byte Select Access
Each chip select with a 16-bit data bus can operate with one of two different types of write access: byte write or
byte select access. This is controlled by the BAT field of the SMC_MODE register for the corresponding chip
select.
Figure 25-4. Memory Connection for an 8-bit Data Bus
Figure 25-5. Memory Connection for a 16-bit Data Bus
25.9.2.1 Byte Write Access
Byte write access supports one byte write signal per byte of the data bus and a single read signal.
Note that the SMC does not allow boot in Byte Write Access mode.
For 16-bit devices: the SMC provides NWR0 and NWR1 write signals for respectively, byte0 (lower byte) and
byte1 (upper byte) of a 16-bit bus. One single read signal (NRD) is provided.
Byte Write Access is used to connect 2 x 8-bit devices as a 16-bit memory.
SMC
A0
NWE
NRD
NCS[2]
A0
Write Enable
Output Enable
Memory Enable
D[7:0] D[7:0]
A[18:2]
A[18:2]
A1 A1
SMC NBS0
NWE
NRD
NCS[2]
Low Byte Enable
Write Enable
Output Enable
Memory Enable
NBS1 High Byte Enable
D[15:0] D[15:0]
A[19:2] A[18:1]
A[0]A1
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25.9.2.2 Byte Select Access
In this mode, read/write operations can be enabled/disabled at byte level. One byte-select line per byte of the data
bus is provided. One NRD and one NWE signal control read and write.
For 16-bit devices: the SMC provides NBS0 and NBS1 selection signals for respectively byte0 (lower byte)
and byte1 (upper byte) of a 16-bit bus.
Byte Select Access is used to connect one 16-bit device.
Figure 25-6. Connection of 2 x 8-bit Devices on a 16-bit Bus: Byte Write Option
25.9.2.3 Signal Multiplexing
Depending on the byte access type (BAT), only the write signals or the byte select signals are used. To save IOs at
the external bus interface, control signals at the SMC interface are multiplexed. Table 25-5 shows signal
multiplexing depending on the data bus width and the byte access type.
For 16-bit devices, bit A0 of address is unused. When Byte Select Option is selected, NWR1 is unused. When Byte
Write option is selected, NBS0 is unused.
SMC A1
NWR0
NRD
NCS[3]
Write Enable
Read Enable
Memory Enable
NWR1
Write Enable
Read Enable
Memory Enable
D[7:0] D[7:0]
D[15:8]
D[15:8]
A[24:2]
A[23:1]
A[23:1]
A[0]
A[0]
Table 25-5. SMC Multiplexed Signal Translation
Signal Name 16-bit Bus 8-bit Bus
Device Type 1x16-bit 2 x 8-bit 1 x 8-bit
Byte Access Type (BAT) Byte Select Byte Write
NBS0_A0 NBS0 A0
NWE_NWR0 NWE NWR0 NWE
NBS1_NWR1 NBS1 NWR1
A1 A1 A1 A1
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25.10 Standard Read and Write Protocols
In the following sections, the byte access type is not considered. Byte select lines (NBS0 to NBS1) always have
the same timing as the A address bus. NWE represents either the NWE signal in byte select access type or one of
the byte write lines (NWR0 to NWR1) in byte write access type. NWR0 to NWR3 have the same timings and
protocol as NWE. In the same way, NCS represents one of the NCS[0..7] chip select lines.
25.10.1 Read Waveforms
The read cycle is shown on Figure 25-7.
The read cycle starts with the address setting on the memory address bus, i.e.:
{A[23:2], A1, A0} for 8-bit devices
{A[23:2], A1} for 16-bit devices
Figure 25-7. Standard Read Cycle
25.10.1.1 NRD Waveform
The NRD signal is characterized by a setup timing, a pulse width and a hold timing.
1. NRD_SETUP: the NRD setup time is defined as the setup of address before the NRD falling edge.
2. NRD_PULSE: the NRD pulse length is the time between NRD falling edge and NRD rising edge.
3. NRD_HOLD: the NRD hold time is defined as the hold time of address after the NRD rising edge.
A[23:2]
NBS0,NBS1,
A0, A1
NCS
NRD_SETUP NRD_PULSE NRD_HOLD
MCK
NRD
D[15:0]
NCS_RD_SETUP NCS_RD_PULSENCS_RD_HOLD
NRD_CYCLE
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25.10.1.2 NCS Waveform
Similarly, the NCS signal can be divided into a setup time, pulse length and hold time:
1. NCS_RD_SETUP: the NCS setup time is defined as the setup time of address before the NCS falling
edge.
2. NCS_RD_PULSE: the NCS pulse length is the time between NCS falling edge and NCS rising edge.
3. NCS_RD_HOLD: the NCS hold time is defined as the hold time of address after the NCS rising edge.
25.10.1.3 Read Cycle
The NRD_CYCLE time is defined as the total duration of the read cycle, i.e., from the time where address is set on
the address bus to the point where address may change. The total read cycle time is equal to:
NRD_CYCLE = NRD_SETUP + NRD_PULSE + NRD_HOLD
= NCS_RD_SETUP + NCS_RD_PULSE + NCS_RD_HOLD
All NRD and NCS timings are defined separately for each chip select as an integer number of Master Clock cycles.
To ensure that the NRD and NCS timings are coherent, the user must define the total read cycle instead of the
hold timing. NRD_CYCLE implicitly defines the NRD hold time and NCS hold time as:
NRD_HOLD = NRD_CYCLE - NRD SETUP - NRD PULSE
NCS_RD_HOLD = NRD_CYCLE - NCS_RD_SETUP - NCS_RD_PULSE
25.10.2 Read Mode
As NCS and NRD waveforms are defined independently of one other, the SMC needs to know when the read data
is available on the data bus. The SMC does not compare NCS and NRD timings to know which signal rises first.
The READ_MODE parameter in the SMC_MODE register of the corresponding chip select indicates which signal
of NRD and NCS controls the read operation.
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25.10.2.1 Read is Controlled by NRD (READ_MODE = 1):
Figure 25-8 shows the waveforms of a read operation of a typical asynchronous RAM. The read data is available
tPACC after the falling edge of NRD, and turns to ‘Z’ after the rising edge of NRD. In this case, the READ_MODE
must be set to 1 (read is controlled by NRD), to indicate that data is available with the rising edge of NRD. The
SMC samples the read data internally on the rising edge of Master Clock that generates the rising edge of NRD,
whatever the programmed waveform of NCS may be.
Figure 25-8. READ_MODE = 1: Data is sampled by SMC before the rising edge of NRD
Data Sampling
tPACC
MCK
A[23:2]
NBS0,NBS1,
A0, A1
NCS
NRD
D[15:0]
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25.10.2.2 Read is Controlled by NCS (READ_MODE = 0)
Figure 25-9 shows the typical read cycle. The read data is valid tPACC after the falling edge of the NCS signal and
remains valid until the rising edge of NCS. Data must be sampled when NCS is raised. In that case, the
READ_MODE must be set to 0 (read is controlled by NCS): the SMC internally samples the data on the rising
edge of Master Clock that generates the rising edge of NCS, whatever the programmed waveform of NRD may be.
Figure 25-9. READ_MODE = 0: Data is sampled by SMC before the rising edge of NCS
Data Sampling
tPACC
MCK
D[15:0]
A[23:2]
NBS0,NBS1,
A0, A1
NCS
NRD
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25.10.3 Write Waveforms
The write protocol is similar to the read protocol. It is depicted in Figure 25-10. The write cycle starts with the
address setting on the memory address bus.
25.10.3.1 NWE Waveforms
The NWE signal is characterized by a setup timing, a pulse width and a hold timing.
1. NWE_SETUP: the NWE setup time is defined as the setup of address and data before the NWE falling
edge.
2. NWE_PULSE: The NWE pulse length is the time between NWE falling edge and NWE rising edge.
3. NWE_HOLD: The NWE hold time is defined as the hold time of address and data after the NWE rising edge.
The NWE waveforms apply to all byte-write lines in Byte Write access mode: NWR0 to NWR3.
25.10.3.2 NCS Waveforms
The NCS signal waveforms in write operation are not the same as those applied in read operations, but are
separately defined:
1. NCS_WR_SETUP: the NCS setup time is defined as the setup time of address before the NCS falling
edge.
2. NCS_WR_PULSE: the NCS pulse length is the time between NCS falling edge and NCS rising edge.
3. NCS_WR_HOLD: the NCS hold time is defined as the hold time of address after the NCS rising edge.
Figure 25-10. Write Cycle
A
[23:2]
NBS0, NBS1,
A0, A1
NCS
NWE_SETUP NWE_PULSE NWE_HOLD
MCK
NWE
NCS_WR_SETUP NCS_WR_PULSE NCS_WR_HOLD
NWE_CYCLE
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25.10.3.3 Write Cycle
The write cycle time is defined as the total duration of the write cycle, that is, from the time where address is set on
the address bus to the point where address may change. The total write cycle time is equal to:
NWE_CYCLE = NWE_SETUP + NWE_PULSE + NWE_HOLD
= NCS_WR_SETUP + NCS_WR_PULSE + NCS_WR_HOLD
All NWE and NCS (write) timings are defined separately for each chip select as an integer number of Master Clock
cycles. To ensure that the NWE and NCS timings are coherent, the user must define the total write cycle instead of
the hold timing. This implicitly defines the NWE hold time and NCS (write) hold times as:
NWE_HOLD = NWE_CYCLE - NWE_SETUP - NWE_PULSE
NCS_WR_HOLD = NWE_CYCLE - NCS_WR_SETUP - NCS_WR_PULSE
25.10.4 Write Mode
The WRITE_MODE parameter in the SMC_MODE register of the corresponding chip select indicates which signal
controls the write operation.
25.10.4.1 Write is Controlled by NWE (WRITE_MODE = 1)
Figure 25-11 shows the waveforms of a write operation with WRITE_MODE set to 1. The data is put on the bus
during the pulse and hold steps of the NWE signal. The internal data buffers are turned out after the NWE_SETUP
time, and until the end of the write cycle, regardless of the programmed waveform on NCS.
Figure 25-11. WRITE_MODE = 1. The write operation is controlled by NWE
MCK
D[15:0]
NCS
A
[23:2]
NBS0, NBS1,
A0, A1
NWE,
NWR0, NWR1
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25.10.4.2 Write is Controlled by NCS (WRITE_MODE = 0)
Figure 25-12 shows the waveforms of a write operation with WRITE_MODE set to 0. The data is put on the bus
during the pulse and hold steps of the NCS signal. The internal data buffers are turned out after the
NCS_WR_SETUP time, and until the end of the write cycle, regardless of the programmed waveform on NWE.
Figure 25-12. WRITE_MODE = 0. The write operation is controlled by NCS
25.10.5 Coding Timing Parameters
All timing parameters are defined for one chip select and are grouped together in one SMC_REGISTER according
to their type.
The SMC_SETUP register groups the definition of all setup parameters: NRD_SETUP, NCS_RD_SETUP,
NWE_SETUP, NCS_WR_SETUP
The SMC_PULSE register groups the definition of all pulse parameters: NRD_PULSE, NCS_RD_PULSE,
NWE_PULSE, NCS_WR_PULSE
The SMC_CYCLE register groups the definition of all cycle parameters: NRD_CYCLE, NWE_CYCLE
Table 25-6 shows how the timing parameters are coded and their permitted range.
MCK
D[15:0]
NCS
NWE,
NWR0, NWR1
A
[23:2]
NBS0, NBS1,
A0, A1
Table 25-6. Coding and Range of Timing Parameters
Coded Value Number of Bits Effective Value
Permitted Range
Coded Value Effective Value
setup [5:0] 6 128 x setup[5] + setup[4:0] 0 ≤ ≤ 31 128 ≤ ≤ 128+31
pulse [6:0] 7 256 x pulse[6] + pulse[5:0] 0 ≤ ≤ 63 256 ≤ ≤ 256+63
cycle [8:0] 9 256 x cycle[8:7] + cycle[6:0] 0 ≤ ≤ 127
256 ≤ ≤ 256+127
512 ≤ ≤ 512+127
768 ≤ ≤ 768+127
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25.10.6 Reset Values of Timing Parameters
Table 25-7 gives the default value of timing parameters at reset.
25.10.7 Usage Restriction
The SMC does not check the validity of the user-programmed parameters. If the sum of SETUP and PULSE
parameters is larger than the corresponding CYCLE parameter, this leads to unpredictable behavior of the SMC.
25.10.7.1 For Read Operations
Null but positive setup and hold of address and NRD and/or NCS can not be guaranteed at the memory interface
because of the propagation delay of theses signals through external logic and pads. If positive setup and hold
values must be verified, then it is strictly recommended to program non-null values so as to cover possible skews
between address, NCS and NRD signals.
25.10.7.2 For Write Operations
If a null hold value is programmed on NWE, the SMC can guarantee a positive hold of address, byte select lines,
and NCS signal after the rising edge of NWE. This is true for WRITE_MODE = 1 only. See “Early Read Wait State”
on page 436.
For read and write operations: a null value for pulse parameters is forbidden and may lead to unpredictable
behavior.
In read and write cycles, the setup and hold time parameters are defined in reference to the address bus. For
external devices that require setup and hold time between NCS and NRD signals (read), or between NCS and
NWE signals (write), these setup and hold times must be converted into setup and hold times in reference to the
address bus.
25.11 Scrambling/Unscrambling Function
The external data bus D[15:0] can be scrambled in order to prevent intellectual property data located in off-chip
memories from being easily recovered by analyzing data at the package pin level of either microcontroller or
memory device.
The scrambling and unscrambling are performed on-the-fly without additional wait states.
The scrambling method depends on two user-configurable key registers, SMC_KEY1 and SMC_KEY2. These key
registers are only accessible in write mode.
The key must be securely stored in a reliable non-volatile memory in order to recover data from the off-chip
memory. Any data scrambled with a given key cannot be recovered if the key is lost.
The scrambling/unscrambling function can be enabled or disabled by programming the SMC_OCMS register.
One bit is dedicated to enable/disable NAND Flash scrambling and one bit is dedicated enable/disable scrambling
the off chip SRAM. When at least one external SRAM is scrambled, the SMSC field must be set in the
SMC_OCMS register.
Table 25-7. Reset Values of Timing Parameters
Register Reset Value Description
SMC_SETUP 0x01010101 All setup timings are set to 1
SMC_PULSE 0x01010101 All pulse timings are set to 1
SMC_CYCLE 0x00030003 The read and write operation last 3 Master Clock cycles
and provide one hold cycle
WRITE_MODE 1 Write is controlled with NWE
READ_MODE 1 Read is controlled with NRD
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When multiple chip selects (external SRAM) are handled, it is possible to configure the scrambling function per
chip select using the OCMS field in the SMC_TIMINGS registers.
To scramble the NAND Flash contents, the SRSE field must be set in the SMC_OCMS register.
When NAND Flash memory content is scrambled, the on-chip SRAM page buffer associated for the transfer is also
scrambled.
25.12 Automatic Wait States
Under certain circumstances, the SMC automatically inserts idle cycles between accesses to avoid bus contention
or operation conflict.
25.12.1 Chip Select Wait States
The SMC always inserts an idle cycle between 2 transfers on separate chip selects. This idle cycle ensures that
there is no bus contention between the de-activation of one device and the activation of the next one.
During chip select wait state, all control lines are turned inactive: NBS0 to NBS1, NWR0 to NWR1, NCS[0..7], NRD
lines are all set to 1.
Figure 25-13 illustrates a chip select wait state between access on Chip Select 0 and Chip Select 2.
Figure 25-13. Chip Select Wait State between a Read Access on NCS0 and a Write Access on NCS2
A[23:2]
NBS0, NBS1,
A0,A1
NCS0
NRD_CYCLE
Chip Select
Wait State
NWE_CYCLE
MCK
NCS2
NRD
NWE
D[15:0]
Read to Write
Wait State
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25.12.2 Early Read Wait State
In some cases, the SMC inserts a wait state cycle between a write access and a read access to allow time for the
write cycle to end before the subsequent read cycle begins. This wait state is not generated in addition to a chip
select wait state. The early read cycle thus only occurs between a write and read access to the same memory
device (same chip select).
An early read wait state is automatically inserted if at least one of the following conditions is valid:
if the write controlling signal has no hold time and the read controlling signal has no setup time (Figure 25-
14).
in NCS write controlled mode (WRITE_MODE = 0), if there is no hold timing on the NCS signal and the
NCS_RD_SETUP parameter is set to 0, regardless of the read mode (Figure 25-15). The write operation
must end with a NCS rising edge. Without an Early Read Wait State, the write operation could not complete
properly.
in NWE controlled mode (WRITE_MODE = 1) and if there is no hold timing (NWE_HOLD = 0), the feedback
of the write control signal is used to control address, data, chip select and byte select lines. If the external
write control signal is not inactivated as expected due to load capacitances, an Early Read Wait State is
inserted and address, data and control signals are maintained one more cycle. See Figure 25-16.
Figure 25-14. Early Read Wait State: Write with No Hold Followed by Read with No Setup
write cycle Early Read
wait state
MCK
NRD
NWE
read cycle
no setup
no hold
D[15:0]
NBS0, NBS1,
A0, A1
A[23:2]
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Figure 25-15. Early Read Wait State: NCS Controlled Write with No Hold Followed by a Read with No NCS Setup
Figure 25-16. Early Read Wait State: NWE-controlled Write with No Hold Followed by a Read with one Set-up Cycle
write cycle
(WRITE_MODE = 0) Early Read
wait state
MCK
NRD
NCS
read cycle
(READ_MODE = 0 or READ_MODE = 1)
no setup
no hold
D[15:0]
NBS0, NBS1,
A0,A1
A[23:2]
A
[23:2]
NBS0, NBS1,
A0, A1
write cycle
(WRITE_MODE = 1) Early Read
wait state
MCK
NRD
internal write controlling signal
external write controlling signal
(NWE)
D[15:0]
read cycle
(READ_MODE = 0 or READ_MODE = 1)
no hold read setup = 1
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25.12.3 Reload User Configuration Wait State
The user may change any of the configuration parameters by writing the SMC user interface.
When detecting that a new user configuration has been written in the user interface, the SMC inserts a wait state
before starting the next access. The so called “Reload User Configuration Wait State” is used by the SMC to load
the new set of parameters to apply to next accesses.
The Reload Configuration Wait State is not applied in addition to the Chip Select Wait State. If accesses before
and after re-programming the user interface are made to different devices (Chip Selects), then one single Chip
Select Wait State is applied.
On the other hand, if accesses before and after writing the user interface are made to the same device, a Reload
Configuration Wait State is inserted, even if the change does not concern the current Chip Select.
25.12.3.1 User Procedure
To insert a Reload Configuration Wait State, the SMC detects a write access to any SMC_MODE register of the
user interface. If only the timing registers are modified (SMC_SETUP, SMC_PULSE, SMC_CYCLE registers) in
the user interface, the user must validate the modification by writing the SMC_MODE register, even if no change
was made on the mode parameters.
25.12.3.2 Slow Clock Mode Transition
A Reload Configuration Wait State is also inserted when the Slow Clock Mode is entered or exited, after the end of
the current transfer (see “Slow Clock Mode” on page 448).
25.12.4 Read to Write Wait State
Due to an internal mechanism, a wait cycle is always inserted between consecutive read and write SMC accesses.
This wait cycle is referred to as a read to write wait state in this document.
This wait cycle is applied in addition to chip select and reload user configuration wait states when they are to be
inserted. See Figure 25-13 on page 435.
25.13 Data Float Wait States
Some memory devices are slow to release the external bus. For such devices, it is necessary to add wait states
(data float wait states) after a read access:
before starting a read access to a different external memory,
before starting a write access to the same device or to a different external one.
The Data Float Output Time (tDF) for each external memory device is programmed in the TDF_CYCLES field of the
SMC_MODE register for the corresponding chip select. The value of TDF_CYCLES indicates the number of data
float wait cycles (between 0 and 15) before the external device releases the bus, and represents the time allowed
for the data output to go to high impedance after the memory is disabled.
Data float wait states do not delay internal memory accesses. Hence, a single access to an external memory with
long tDF will not slow down the execution of a program from internal memory.
The data float wait states management depends on the READ_MODE and the TDF_MODE fields of the
SMC_MODE register for the corresponding chip select.
25.13.1 READ_MODE
Setting READ_MODE to 1 indicates to the SMC that the NRD signal is responsible for turning off the tri-state
buffers of the external memory device. The Data Float Period then begins after the rising edge of the NRD signal
and lasts TDF_CYCLES MCK cycles.
When the read operation is controlled by the NCS signal (READ_MODE = 0), the TDF field gives the number of
MCK cycles during which the data bus remains busy after the rising edge of NCS.
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Figure 25-17 illustrates the Data Float Period in NRD-controlled mode (READ_MODE =1), assuming a data float
period of 2 cycles (TDF_CYCLES = 2). Figure 25-18 shows the read operation when controlled by NCS
(READ_MODE = 0) and the TDF_CYCLES parameter equals 3.
Figure 25-17. TDF Period in NRD Controlled Read Access (TDF = 2)
Figure 25-18. TDF Period in NCS Controlled Read Operation (TDF = 3)
NBS0, NBS1,
A0, A1
NCS
NRD controlled read operation
tpacc
MCK
NRD
D[15:0]
TDF = 2 clock cycles
A[23:2]
NCS
TDF = 3 clock cycles
tpacc
MCK
D[15:0]
NCS controlled read operation
A[23:2]
NBS0, NBS1,
A0,A1
NRD
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25.13.2 TDF Optimization Enabled (TDF_MODE = 1)
When the TDF_MODE of the SMC_MODE register is set to 1 (TDF optimization is enabled), the SMC takes
advantage of the setup period of the next access to optimize the number of wait states cycle to insert.
Figure 25-19 shows a read access controlled by NRD, followed by a write access controlled by NWE, on Chip
Select 0. Chip Select 0 has been programmed with:
NRD_HOLD = 4; READ_MODE = 1 (NRD controlled)
NWE_SETUP = 3; WRITE_MODE = 1 (NWE controlled)
TDF_CYCLES = 6; TDF_MODE = 1 (optimization enabled).
Figure 25-19. TDF Optimization: No TDF wait states are inserted if the TDF period is over when the next access begins
25.13.3 TDF Optimization Disabled (TDF_MODE = 0)
When optimization is disabled, tdf wait states are inserted at the end of the read transfer, so that the data float
period ends when the second access begins. If the hold period of the read1 controlling signal overlaps the data
float period, no additional tdf wait states will be inserted.
Figure 25-20, Figure 25-21 and Figure 25-22 illustrate the cases:
read access followed by a read access on another chip select,
read access followed by a write access on another chip select,
read access followed by a write access on the same chip select,
with no TDF optimization.
A
[23:2]
NCS0
MCK
NRD
NWE
D[15:0]
Read to Write
Wait State
TDF_CYCLES = 6
read access on NCS0 (NRD controlled)
NRD_HOLD= 4
NWE_SETUP= 3
write access on NCS0 (NWE controlled)
11L /\ .I.||||\/||||\/AII III: pl
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Figure 25-20. TDF Optimization Disabled (TDF Mode = 0). TDF wait states between 2 read accesses on different chip selects
Figure 25-21. TDF Mode = 0: TDF wait states between a read and a write access on different chip selects
TDF_CYCLES = 6
TDF_CYCLES = 6 TDF_MODE = 0
(optimization disabled)
A[
23:2]
read1 cycle
Chip Select Wait State
MCK
read1 controlling signal
(NRD)
read2 controlling signal
(NRD)
D[15:0]
read1 hold = 1
read 2 cycle
read2 setup = 1
5 TDF WAIT STATES
NBS0, NBS1,
A0, A1
TDF_CYCLES = 4
TDF_CYCLES = 4 TDF_MODE = 0
(optimization disabled)
A
[23:2]
read1 cycle
Chip Select
Wait State
Read to Write
Wait State
MCK
read1 controlling signal
(NRD)
write2 controlling signal
(NWE)
D[15:0]
read1 hold = 1
write2 cycle
write2 setup = 1
2 TDF WAIT STATES
NBS0, NBS1,
A0, A1
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Figure 25-22. TDF Mode = 0: TDF wait states between read and write accesses on the same chip select
25.14 External Wait
Any access can be extended by an external device using the NWAIT input signal of the SMC. The EXNW_MODE
field of the SMC_MODE register on the corresponding chip select must be set to either to “10” (frozen mode) or
“11” (ready mode). When the EXNW_MODE is set to “00” (disabled), the NWAIT signal is simply ignored on the
corresponding chip select. The NWAIT signal delays the read or write operation in regards to the read or write
controlling signal, depending on the read and write modes of the corresponding chip select.
25.14.1 Restriction
When one of the EXNW_MODE is enabled, it is mandatory to program at least one hold cycle for the read/write
controlling signal. For that reason, the NWAIT signal cannot be used in Slow Clock Mode (“Slow Clock Mode” on
page 448).
The NWAIT signal is assumed to be a response of the external device to the read/write request of the SMC. Then
NWAIT is examined by the SMC only in the pulse state of the read or write controlling signal. The assertion of the
NWAIT signal outside the expected period has no impact on SMC behavior.
25.14.2 Frozen Mode
When the external device asserts the NWAIT signal (active low), and after internal synchronization of this signal,
the SMC state is frozen, i.e., SMC internal counters are frozen, and all control signals remain unchanged. When
the resynchronized NWAIT signal is deasserted, the SMC completes the access, resuming the access from the
point where it was stopped. See Figure 25-23. This mode must be selected when the external device uses the
NWAIT signal to delay the access and to freeze the SMC.
The assertion of the NWAIT signal outside the expected period is ignored as illustrated in Figure 25-24.
TDF_CYCLES = 5
TDF_CYCLES = 5
TDF_MODE = 0
(optimization disabled)
A
[23:2]
read1 cycle
Read to Write
Wait State
MCK
read1 controlling signal
(NRD)
write2 controlling signal
(NWE)
D[15:0]
read1 hold = 1
write2 cycle
write2 setup = 1
4 TDF WAIT STATES
NBS0, NBS1,
A0, A1
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Figure 25-23. Write Access with NWAIT Assertion in Frozen Mode (EXNW_MODE = 10)
EXNW_MODE = 10 (Frozen)
WRITE_MODE = 1 (NWE_controlled)
NWE_PULSE = 5
NCS_WR_PULSE = 7
A
[23:2]
MCK
NWE
NCS
432 1 1101
4563222210
Write cycle
D[15:0]
NWAIT
FROZEN STATE
NBS0, NBS1,
A0,A1
Internally synchronized
NWAIT signal
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Figure 25-24. Read Access with NWAIT Assertion in Frozen Mode (EXNW_MODE = 10)
EXNW_MODE = 10 (Frozen)
READ_MODE = 0 (NCS_controlled)
NRD_PULSE = 2, NRD_HOLD = 6
NCS_RD_PULSE =5, NCS_RD_HOLD =3
A
[23:2]
MCK
NCS
NRD
10
43
43
2
555
22 0 210
210
1
Read cycle
Assertion is ignored
NWAIT
Internally synchronized
NWAIT signal
FROZEN STATE
NBS0, NBS1,
A0,A1
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25.14.3 Ready Mode
In Ready mode (EXNW_MODE = 11), the SMC behaves differently. Normally, the SMC begins the access by
down counting the setup and pulse counters of the read/write controlling signal. In the last cycle of the pulse
phase, the resynchronized NWAIT signal is examined.
If asserted, the SMC suspends the access as shown in Figure 25-25 and Figure 25-26. After deassertion, the
access is completed: the hold step of the access is performed.
This mode must be selected when the external device uses deassertion of the NWAIT signal to indicate its ability
to complete the read or write operation.
If the NWAIT signal is deasserted before the end of the pulse, or asserted after the end of the pulse of the
controlling read/write signal, it has no impact on the access length as shown in Figure 25-26.
Figure 25-25. NWAIT Assertion in Write Access: Ready Mode (EXNW_MODE = 11)
EXNW_MODE = 11 (Ready mode)
WRITE_MODE = 1 (NWE_controlled)
NWE_PULSE = 5
NCS_WR_PULSE = 7
A
[23:2]
MCK
NWE
NCS
432 1 000
456321110
Write cycle
D[15:0]
NWAIT
Internally synchronized
NWAIT signal
Wait STATE
NBS0, NBS1,
A0,A1
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Figure 25-26. NWAIT Assertion in Read Access: Ready Mode (EXNW_MODE = 11)
EXNW_MODE = 11(Ready mode)
READ_MODE = 0 (NCS_controlled)
NRD_PULSE = 7
NCS_RD_PULSE =7
A[23:2]
MCK
NCS
NRD
4563200
0
1
4563211
Read cycle
Assertion is ignored
NWAIT
Internally synchronized
NWAIT signal
Wait STATE
Assertion is ignored
NBS0, NBS1,
A0,A1
IJTfiIS IN.A.|DI
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25.14.4 NWAIT Latency and Read/Write Timings
There may be a latency between the assertion of the read/write controlling signal and the assertion of the NWAIT
signal by the device. The programmed pulse length of the read/write controlling signal must be at least equal to
this latency plus the 2 cycles of resynchronization + 1 cycle. Otherwise, the SMC may enter the hold state of the
access without detecting the NWAIT signal assertion. This is true in frozen mode as well as in ready mode. This is
illustrated on Figure 25-27.
When EXNW_MODE is enabled (ready or frozen), the user must program a pulse length of the read and write
controlling signal of at least:
minimal pulse length = NWAIT latency + 2 resynchronization cycles + 1 cycle
Figure 25-27. NWAIT Latency
EXNW_MODE = 10 or 11
READ_MODE = 1 (NRD_controlled)
NRD_PULSE = 5
A
[23:2]
MCK
NRD
43 210 00
Read cycle
minimal pulse length
NWAIT latency
NWAIT
Intenally synchronized
NWAIT signal
WAIT STATE
2 cycle resynchronization
NBS0, NBS1,
A0,A1
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25.15 Slow Clock Mode
The SMC is able to automatically apply a set of “slow clock mode” read/write waveforms when an internal signal
driven by the Power Management Controller is asserted because MCK has been turned to a very slow clock rate
(typically 32 kHz clock rate). In this mode, the user-programmed waveforms are ignored and the slow clock mode
waveforms are applied. This mode is provided so as to avoid reprogramming the User Interface with appropriate
waveforms at very slow clock rate. When activated, the slow mode is active on all chip selects.
25.15.1 Slow Clock Mode Waveforms
Figure 25-28 illustrates the read and write operations in slow clock mode. They are valid on all chip selects. Table
25-8 indicates the value of read and write parameters in slow clock mode.
Figure 25-28. Read/Write Cycles in Slow Clock Mode
25.15.2 Switching from (to) Slow Clock Mode to (from) Normal Mode
When switching from slow clock mode to normal mode, the current slow clock mode transfer is completed at high
clock rate, with the set of slow clock mode parameters. See Figure 25-29. The external device may not be fast
enough to support such timings.
Figure 25-30 illustrates the recommended procedure to properly switch from one mode to the other.
A[
23:2]
NCS
1
MCK
NWE 1
1
NWE_CYCLE = 3
A
[23:2]
MCK
NRD
NRD_CYCLE = 2
1
1
NCS
SLOW CLOCK MODE WRITE SLOW CLOCK MODE READ
NBS0, NBS1,
A0,A1 NBS0, NBS1,
A0,A1
Table 25-8. Read and Write Timing Parameters in Slow Clock Mode
Read Parameters Duration (cycles) Write Parameters Duration (cycles)
NRD_SETUP 1 NWE_SETUP 1
NRD_PULSE 1 NWE_PULSE 1
NCS_RD_SETUP 0 NCS_WR_SETUP 0
NCS_RD_PULSE 2 NCS_WR_PULSE 3
NRD_CYCLE 2 NWE_CYCLE 3
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Figure 25-29. Clock Rate Transition Occurs while the SMC is Performing a Write Operation
Figure 25-30. Recommended Procedure to Switch from Slow Clock Mode to Normal Mode or from Normal Mode to Slow Clock
Mode
A
[23:2]
NCS
1
MCK
NWE
1
1
NWE_CYCLE = 3
SLOW CLOCK MODE WRITE
Slow Clock Mode
internal signal from PMC
111 2 32
NWE_CYCLE = 7
NORMAL MODE WRITE
Slow clock mode transition is detected:
Reload Configuration Wait State
This write cycle finishes with the slow clock mode set
of parameters after the clock rate transition
SLOW CLOCK MODE WRITE
NBS0, NBS1,
A0, A1
A
[23:2]
NCS
1
MCK
NWE
1
1
SLOW CLOCK MODE WRITE
Slow Clock Mode
internal signal from PMC
232
NORMAL MODE WRITEIDLE STATE
Reload Configuration
Wait State
NBS0, NBS1,
A0, A1
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25.16 NAND Flash Controller Operations
25.16.1 NFC Overview
The NFC can handle automatic transfers, sending the commands and address to the NAND Flash and transferring
the contents of the page (for read and write) to the NFC SRAM. It minimizes the CPU overhead.
25.16.2 NFC Control Registers
NAND Flash Read and NAND Flash Program operations can be performed through the NFC Command Registers.
In order to minimize CPU intervention and latency, commands are posted in a command buffer. This buffer
provides zero wait state latency. The detailed description of the command encoding scheme is explained below.
The NFC handles automatic transfer between the external NAND Flash and the chip via the NFC SRAM. It is done
via NFC Command Registers.
The NFC Command Registers are very efficient to use. When writing to these registers:
the address of the register (NFCADDR_CMD) contains the command used,
the data of the register (NFCDATA_ADDT) contains the address to be sent to the NAND Flash.
So, in one single access the command is sent and immediately executed by the NFC. Even two commands can be
programed within a single access (CMD1, CMD2) depending on the VCMD2 value.
The NFC can send up to 5 Address cycles.
Figure 25-31 below shows a typical NAND Flash Page Read Command of a NAND Flash Memory and
correspondence with NFC Address Command Register.
Figure 25-31. NFC/NAND Flash Access Example
For more details refer to “NFC Address Command” on page 452.
The NFC Command Registers can be found at address 0x68000000 - 0x6FFFFFFF. (See Table 25-4, “External
Memory Mapping”.)
Reading the NFC command register (to any address) will give the status of the NFC. Especially useful to know if
the NFC is busy, for example.
Depends on ACYCLE value
CMD1 ADD cycles (0 to 5) CMD2
If VCMD2 = 1
00h Col. Add1 Col. Add2 Row Add1 Row Add2 Row Add3 30h
Column Address Row Address
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25.16.2.1 Building NFC Address Command Example.
The base address is made of address 0x60000000 + NFCCMD bit set = 0x68000000.
Page read operation example:
// Build the Address Command (NFCADDR_CMD)
AddressCommand = (0x60000000 |
NFCCMD=1 | // NFC Command Enable
NFCWR=0 |// NFC Read Data from NAND Flash
NFCEN=1 | // NFC Enable.
CSID=1 | // Chip Select ID = 1
ACYCLE= 5 | // Number of address cycle.
VCMD2=1 | // CMD2 is sent after Address Cycles
CMD2=0x30 | // CMD2 = 30h
CMD1=0x0) // CMD1 = Read Command = 00h
// Set the Address for Cycle 0
SMC_ADDR = Col. Add1
// Write command with the Address Command built above
*AddressCommand = (Col. Add2 |// ADDR_CYCLE1
Row Add1 | // ADDR_CYCLE2
Row Add2 |// ADDR_CYCLE3
Row Add3 )// ADDR_CYCLE4
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25.16.2.2 NFC Address Command
Name: NFCADDR_CMD
Access: Read-write
Reset: 0x00000000
• CMD1: Command Register Value for Cycle 1
If NFCCMD is set, when a read or write access occurs, the NFC sends this command.
• CMD2: Command Register Value for Cycle 2
If NFCCMD and VCMD2 field are set to one, the NFC sends this command after CMD1.
• VCMD2: Valid Cycle 2 Command
When set to true, the CMD2 field is issued after addressing cycle.
• ACYCLE: Number of Address required for the current command
When ACYCLE field is different from zero, ACYCLE Address cycles are performed after Command Cycle 1. The maximum
number of cycles is 5.
• CSID: Chip Select Identifier
Chip select used
• NFCEN: NFC Enable
When set to true, the NFC will automatically read or write data after the command.
• NFCWR: NFC Write Enable
0: The NFC reads data from the NAND Flash.
1: The NFC writes data into the NAND Flash.
• NFCCMD: NFC Command Enable
If set to true, CMD indicates that the NFC shall execute the command encoded in the NFCADDR_CMD.
31 30 29 28 27 26 25 24
––––NFCCMDNFCWRNFCENCSID
23 22 21 20 19 18 17 16
CSID ACYCLE VCMD2 CMD2
15 14 13 12 11 10 9 8
CMD2 CMD1
76543210
CMD1 – –
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25.16.2.3 NFC Data Address
Name: NFCDATA_ADDT
Access: Write
Reset: 0x00000000
• ADDR_CYCLE1: NAND Flash Array Address Cycle 1
When less than 5 address cycles are used ADDR_CYCLE1 is the first byte written to NAND Flash
When 5 address cycles are used ADDR_CYCLE1 is the second byte written to NAND Flash
• ADDR_CYCLE2: NAND Flash Array Address Cycle 2
When less than 5 address cycles are used ADDR_CYCLE2 is the second byte written to NAND Flash
When 5 address cycles are used ADDR_CYCLE2 is the third byte written to NAND Flash
• ADDR_CYCLE3: NAND Flash Array Address Cycle 3
When less than 5 address cycles are used ADDR_CYCLE3 is the third byte written to NAND Flash
When 5 address cycles are used ADDR_CYCLE3 is the fourth byte written to NAND Flash
• ADDR_CYCLE4: NAND Flash Array Address Cycle 4
When less than 5 address cycles are used ADDR_CYCLE4 is the fourth byte written to NAND Flash
When 5 address cycles are used ADDR_CYCLE4 is the fifth byte written to NAND Flash
Note that if 5 address cycles are used, the first address cycle is ADDR_CYCLE0. Please refer to SMC_ADDR register.
31 30 29 28 27 26 25 24
ADDR_CYCLE4
23 22 21 20 19 18 17 16
ADDR_CYCLE3
15 14 13 12 11 10 9 8
ADDR_CYCLE2
76543210
ADDR_CYCLE1
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25.16.2.4 NFC DATA Status
Name: NFCDATA_Status
Access: Read
Reset: 0x00000000
• CMD1: Command Register Value for Cycle 1
When a Read or Write Access occurs, the Physical Memory Interface drives the IO bus with CMD1 field during the Com-
mand Latch cycle 1.
• CMD2: Command Register Value for Cycle 2
When VCMD2 field is set to true, the Physical Memory Interface drives the IO bus with CMD2 field during the Command
Latch cycle 2.
• VCMD2: Valid Cycle 2 Command
When set to true, the CMD2 field is issued after addressing cycle.
• ACYCLE: Number of Address required for the current command
When ACYCLE field is different from zero, ACYCLE Address cycles are performed after Command Cycle 1.
• CSID: Chip Select Identifier
Chip select used
• NFCEN: NFC Enable
When set to true, The NFC is enabled.
• NFCWR: NFC Write Enable
0: The NFC is in read mode.
1: The NFC is in write mode.
• NFCBUSY: NFC Busy Status Flag
If set to true, it indicates that the NFC is busy.
31 30 29 28 27 26 25 24
––––NFCBUSYNFCWRNFCENCSID
23 22 21 20 19 18 17 16
CSID ACYCLE VCMD2 CMD2
15 14 13 12 11 10 9 8
CMD2 CMD1
76543210
CMD1 – –
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25.16.3 NFC Initialization
Prior to any Command and Data Transfer, the SMC User Interface must be configured to meet the device timing
requirements.
Write enable Configuration
Use NWE_SETUP, NWE_PULSE and NWE_CYCLE to define the write enable waveform according to datasheet
of the device.
Use TADL field in the SMC_TIMINGS register to configure the timing between the last address latch cycle and the
first rising edge of WEN for data input.
Figure 25-32. Write Enable Timing Configuration
Figure 25-33. Write Enable Timing for NAND Flash Device Data Input Mode.
Read Enable Configuration
Use NRD_SETUP, NRD_PULSE and NRD_CYCLE to define the read enable waveform according to the
datasheet of the device.
Use TAR field in the SMC_TIMINGS register to configure the timings between address latch enable falling edge to
read enable falling edge.
Use TCLR field in the SMC_TIMINGS register to configure the timings between the command latch enable falling
edge to the read enable falling edge.
mck
wen
tWEN_PULSEtWEN_SETUP tWEN_HOLD
tWEN_CYCLES
t
ADL
mck
ale
wen
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Figure 25-34. Read Enable Timing Configuration Working with NAND Flash Device
Ready/Busy Signal Timing configuration working with a NAND Flash device
Use TWB field in SMC_TIMINGS register to configure the maximum elapsed time between the rising edge of wen
signal and the falling edge of rbn signal. Use TRR field in the SMC_TIMINGS register to program the number of
clock cycle between the rising edge of the rbn signal and the falling edge of ren signal.
Figure 25-35. Ready/Busy Timing Configuration
mck
cle
ale
cen
ren
tREN_PULSE tREHtREN_SETUP
tREN_CYCLE
tCLR
tAR
mck
wen
ren
rbn
t
RR
t
WB
busy
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25.16.3.1 NAND Flash Controller Timing Engine
When the NFC Command register is written, the NFC issues a NAND Flash Command and optionally performs a
data transfer between the NFC SRAM and the NAND Flash device. The NAND Flash Controller Timing Engine
guarantees valid NAND Flash timings, depending on the set of parameters decoded from the address bus. These
timings are defined in the SMC_TIMINGS register.
For information of the timing used depending on the command, see Figure 25-36:
Figure 25-36. NAND Flash Controller Timing Engine
See ”NFC Address Command” register description and ”SMC Timings Register”.
NFCEN=1 NFCWR =1 TADL =1
NFCEN=1 NFCWR=0 TWB != 0
NFCEN=0 VCMD2=1 TCLR != 0
!NFCEN=1 VCMD2=0 ACYCLE!=0 NFCWR=1 TADL != 0
!NFCEN=1 VCMD2=0 ACYCLE!=0 NFCWR=0 TAR != 0
!NFCEN=1 VCMD2=0 ACYCLE!=0 TCLR != 0
Wait TADL
Wait TADL
Wait TAR
Wait TWB
Wait TCLR
Wait TCLR
Timing Check Engine
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25.16.4 NFC SRAM
25.16.4.1 NFC SRAM Mapping
If the NFC is used to read and write Data from and to the NAND Flash, the configuration depends on the page
size. See Table 25-9and Table 25-10 for detailed mapping.
The NFC SRAM size is 4 Kbytes. The NFC can handle NAND Flash with a page size of 4 Kbytes or of course
lower size (such as 2 Kbytes for example). In the case of 2 Kbytes or lower page size, the NFC SRAM can be split
into several banks. The SMC_BANK field enables to select the bank used.
Note that a “ping-pong” mode (write or read to a bank while the NFC writes or reads to another bank) is not
accessible with the NFC (using 2 different banks).
If the NFC is not used, the NFC SRAM can be used as general purpose by the application.
Table 25-9. NFC SRAM Mapping with NAND Flash Page Size of 2 Kbytes + 64 bytes
Offset Use Access
0x00000000-0x000001FF Bank 0 Main Area Buffer 0 Read-write
0x00000200-0x000003FF Bank 0 Main Area Buffer 1 Read-write
0x00000400-0x000005FF Bank 0 Main Area Buffer 2 Read-write
0x00000600-0x000007FF Bank 0 Main Area Buffer 3 Read-write
0x00000800-0x0000080F Bank 0 Spare Area 0 Read-write
0x00000810-0x0000081F Bank 0 Spare Area 1 Read-write
0x00000820-0x0000082F Bank 0 Spare Area 2 Read-write
0x00000830-0x0000083F Bank 0 Spare Area 3 Read-write
0x00000840-0x00000A3F Bank 1 Main Area Buffer 0 Read-write
0x00000A40-0x00000C3F Bank 1 Main Area Buffer 1 Read-write
0x00000C40-0x00000E3F Bank 1 Main Area Buffer 2 Read-write
0x00000E40-0x0000103F Bank 1 Main Area Buffer 3 Read-write
0x00001040-0x0000104F Bank 1 Spare Area 0 Read-write
0x00001050-0x0000105F Bank 1 Spare Area 1 Read-write
0x00001060-0x0000106F Bank 1 Spare Area 2 Read-write
0x00001070-0x0000107F Bank 1 Spare Area 3 Read-write
0x00001080-0x00001FFF Reserved –
Table 25-10. NFC SRAM Mapping with NAND Flash Page Size of 4 Kbytes + 128 bytes
Offset Use Access
0x00000000-0x000001FF Bank 0 Main Area Buffer 0 Read-write
0x00000200-0x000003FF Bank 0 Main Area Buffer 1 Read-write
0x00000400-0x000005FF Bank 0 Main Area Buffer 2 Read-write
0x00000600-0x000007FF Bank 0 Main Area Buffer 3 Read-write
0x00000800-0x000009FF Bank 0 Main Area Buffer 4 Read-write
0x00000A00-0x00000BFF Bank 0 Main Area Buffer 5 Read-write
0x00000C00-0x00000DFF Bank 0 Main Area Buffer 6 Read-write
0x00000E00-0x00000FFF Bank 0 Main Area Buffer 7 Read-write
0x00001000-0x0000100F Bank 0 Spare Area 0 Read-write
0x00001010-0x0000101F Bank 0 Spare Area 1 Read-write
0x00001020-0x0000102F Bank 0 Spare Area 2 Read-write
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25.16.4.2 NFC SRAM Access Prioritization Algorithm
When the NAND Flash Controller (NFC) is reading from or writing to the NFC SRAM, the internal memory is no
longer accessible. If an NFC SRAM access occurs when the NFC performs a read or write operation then the
access is discarded. The write operation is not performed. The read operation returns undefined data. If this
situation is encountered, the status flag AWB located in the NFC status Register is raised and indicates that a
shared resource access violation has occurred.
25.16.5 NAND Flash Operations
This section describes the software operations needed to issue commands to the NAND Flash device and perform
data transfers using NFC.
0x00001030-0x0000103F Bank 0 Spare Area 3 Read-write
0x00001040-0x0000104F Bank 0 Spare Area 4 Read-write
0x00001050-0x0000105F Bank 0 Spare Area 5 Read-write
0x00001060-0x0000106F Bank 0 Spare Area 6 Read-write
0x00001070-0x0000107F Bank 0 Spare Area 7 Read-write
0x00001080-0x00001FFF Reserved –
Table 25-10. NFC SRAM Mapping with NAND Flash Page Size of 4 Kbytes + 128 bytes
Offset Use Access
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25.16.5.1 Page Read
Figure 25-37. Page Read Flow Chart
Note that instead of using the interrupt one can poll the NFCBUSY Flag.
For more information on the NFC Control Register, see Section 25.16.2.2 ”NFC Address Command”.
Configure Device,
writing in theUser Interface
Write the NFC
Command registers
Enable XFRDONE
interrupt (SMC_IER)
Wait for Interrupt
Copy the data from NFC
SRAM to application
memory (via DMA for example)
Using NFC
Check Error
Correcting Codes
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25.16.5.2 Program Page
Figure 25-38. Program Page Flow Chart
Writing the ECC can not be done using the NFC so it needs to be done “manually”.
Note that instead of using the interrupt one can poll the NFCBUSY Flag.
For more information on the NFC Control Register, see Section 25.16.2.2 ”NFC Address Command”.
25.17 SMC Error Correcting Code Functional Description
A page in NAND Flash and SmartMedia memories contains an area for main data and an additional area used for
redundancy (ECC). The page is organized in 8-bit or 16-bit words. The page size corresponds to the number of
words in the main area plus the number of words in the extra area used for redundancy.
Over time, some memory locations may fail to program or erase properly. In order to ensure that data is stored
properly over the life of the NAND Flash device, NAND Flash providers recommend to utilize either 1 ECC per 256
bytes of data, 1 ECC per 512 bytes of data or 1 ECC for all of the page.
The only configurations required for ECC are the NAND Flash or the SmartMedia page size (528/2112/4224) and
the type of correction wanted (1 ECC for all the page/1 ECC per 256 bytes of data /1 ECC per 512 bytes of data).
Configure Device,
writing in the User
interface
Write Data in the NFC
SRAM (CPU or DMA)
Enable XFRDONE
Write the Command
Register through the
AHB interface
Write ECC
Wait for interrupt
Wait for Ready/Busy
interrupt
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Page size is configured setting the PAGESIZE field in the ECC Mode Register (ECC_MR). Type of correction is
configured setting the TYPCORRECT field in the ECC Mode Register (ECC_MR).
Note that there is a limitation when using 16-bit NAND Flash: only 1 ECC for all of page is possible. For 8-bit
NAND Flash there is no limitation.
ECC is automatically computed as soon as a read (00h)/write (80h) command to the NAND Flash or the
SmartMedia is detected. Read and write access must start at a page boundary.
ECC results are available as soon as the counter reaches the end of the main area. Values in the ECC Parity
Registers (ECC_PR0 to ECC_PR15) are then valid and locked until a new start condition occurs (read/write
command followed by address cycles).
25.17.1 Write Access
Once the Flash memory page is written, the computed ECC codes are available in the ECC Parity (ECC_PR0 to
ECC_PR15) registers. The ECC code values must be written by the software application in the extra area used for
redundancy. The number of write accesses in the extra area is a function of the value of the type of correction field.
For example, for 1 ECC per 256 bytes of data for a page of 512 bytes, only the values of ECC_PR0 and ECC_PR1
must be written by the software application. Other registers are meaningless.
25.17.2 Read Access
After reading the whole data in the main area, the application must perform read accesses to the extra area where
ECC code has been previously stored. Error detection is automatically performed by the ECC controller. Please
note that it is mandatory to read consecutively the entire main area and the locations where Parity and NParity
values have been previously stored to let the ECC controller perform error detection.
The application can check the ECC Status Registers (ECC_SR1/ECC_SR2) for any detected errors. It is up to the
application to correct any detected error. ECC computation can detect four different circumstances:
No error: XOR between the ECC computation and the ECC code stored at the end of the NAND Flash or
SmartMedia page is equal to 0. No error flags in the ECC Status Registers (ECC_SR1/ECC_SR2).
Recoverable error: Only the RECERR flags in the ECC Status registers (ECC_SR1/ECC_SR2) are set. The
corrupted word offset in the read page is defined by the WORDADDR field in the ECC Parity Registers
(ECC_PR0 to ECC_PR15). The corrupted bit position in the concerned word is defined in the BITADDR field
in the ECC Parity Registers (ECC_PR0 to ECC_PR15).
ECC error: The ECCERR flag in the ECC Status Registers (ECC_SR1/ECC_SR2) is set. An error has been
detected in the ECC code stored in the Flash memory. The position of the corrupted bit can be found by the
application performing an XOR between the Parity and the NParity contained in the ECC code stored in the
Flash memory.
Non correctable error: The MULERR flag in the ECC Status Registers (ECC_SR1/ECC_SR2) is set. Several
unrecoverable errors have been detected in the Flash memory page.
ECC Status Registers, ECC Parity Registers are cleared when a read/write command is detected or a software
reset is performed.
For Single-bit Error Correction and Double-bit Error Detection (SEC-DED) Hsiao code is used. 24-bit ECC is
generated in order to perform one bit correction per 256 or 512 bytes for pages of 512/2048/4096 8-bit words. 32-
bit ECC is generated in order to perform one bit correction per 512/1024/2048/4096 8- or 16-bit words. They are
generated according to the schemes shown in Figure 25-39 and Figure 25-40.
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Figure 25-39. Parity Generation for 512/1024/2048/4096 8-bit Words
To calculate P8’ to PX’ and P8 to PX, apply the algorithm that follows.
Page size = 2n
for i =0 to n
begin
for (j = 0 to page_size_byte)
begin
if(j[i] ==1)
P[2i+3]=bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2i+3]
else
P[2i+3]’=bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2i+3]'
end
end
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
P8
P8'
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
P8
P8'
P16
P16'
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
P8
P8'
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
P8
P8'
P16
P16'
P32
P32
1st byte
P32
2nd byte
3rd byte
4 th byte
Page size th byte
(page size -1 )th byte
PX
PX'
Page size = 512 Px = 2048
Page size = 1024 Px = 4096
Page size = 2048 Px = 8192
Page size = 4096 Px = 16384
(page size -2 )th byte
(page size -3 )th byte
P1 P1' P1'
P1 P1 P1' P1'
P1
P2 P2' P2 P2'
P4 P4'
P1=bit7(+)bit5(+)bit3(+)bit1(+)P1
P2=bit7(+)bit6(+)bit3(+)bit2(+)P2
P4=bit7(+)bit6(+)bit5(+)bit4(+)P4
P1'=bit6(+)bit4(+)bit2(+)bit0(+)P1'
P2'=bit5(+)bit4(+)bit1(+)bit0(+)P2'
P4'=bit7(+)bit6(+)bit5(+)bit4(+)P4'
Ems an” 3qu Bid] 5M1 BIuo 5ng BIKE Bun Ems IaIIs Im an: m2 BI" aIIo BIKIS EIIM mus mm mm Emu any Bus Bin Bus 3st mm an: mu 5le mm In W _ _ PX BIIIS am 3qu 3qu arm BIKIO mm am; st7 ans ms EM nu: ma BIH mu: m Ems BIII4 mm mm BIKII sum le9 ans am am; ms mu aux mu KIII mm In I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I am; am 3qu 3qu arm BIKIO Bug Bug w Ems ms EM nu: ma BIH mu: m sIus BIII4 mm mm BIKII Bum m an Bun am; ms an an: mu KIKI mm In m _ _ Px‘ BIHS mm mm aim BnII sum my am; am Bnfi nus HIM an: aux BIKI EIw N am; EIIIA am am BKII am an; a.“ BM sue m5 m an: m an I2! | W H PI' H W H PZ‘ | | "4| PZ‘JI "4| ”‘4 | P4 || P4' | | PA II N | | PS | | PS‘ | Page sze = 5I2 Px=204u PI:bIIIsI+IbIIIsI+Ibm I Hum“) Page m =m24 Px- 4096 mmIIIIsI+IbII3I+IbIII I+II>I Pagan: 2043? ml P2=hIIIsI+IhIIw+Ibmmunch) Page we : 4096 V 6334 bun-HI:IMHMSI-flbnlmn Pkall 5mm 41+)an 3I+Ibm2w IIII7I+IbIIaI+IbII5I+IhII4I+m ”=th swam Awbm 3mm 2m bl" Imbm ut+IbI191+Ibn8 as AtmeL
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Figure 25-40. Parity Generation for 512/1024/2048/4096 16-bit Words
To calculate P8’ to PX’ and P8 to PX, apply the algorithm that follows.
Page size = 2n
for i =0 to n
begin
for (j = 0 to page_size_word)
begin
if(j[i] ==1)
P[2i+3]= bit15(+)bit14(+)bit13(+)bit12(+)
bit11(+)bit10(+)bit9(+)bit8(+)
bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2n+3]
else
P[2i+3]’=bit15(+)bit14(+)bit13(+)bit12(+)
bit11(+)bit10(+)bit9(+)bit8(+)
bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2i+3]'
end
end
1st word
2nd word
3rd word
4th word
(Page size -3 )th word
(Page size -2 )th word
(Page size -1 )th word
Page size th word (+)(+)
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25.18 Static Memory Controller (SMC) User Interface
The SMC is programmed using the fields listed in Table 25-11. For each chip select a set of 4 registers is used to
program the parameters of the external device. In Table 25-11, “CS_number” denotes chip select number. 16
bytes per chip select are required.
Table 25-11. Register Mapping
Offset Register Name Access Reset
0x000 SMC NFC Configuration Register SMC_CFG Read-write 0x0
0x004 SMC NFC Control Register SMC_CTRL Write-only 0x0
0x008 SMC NFC Status Register SMC_SR Read-only 0x0
0x00C SMC NFC Interrupt Enable Register SMC_IER Write-only 0x0
0x010 SMC NFC Interrupt Disable Register SMC_IDR Write-only 0x0
0x014 SMC NFC Interrupt Mask Register SMC_IMR Read-only 0x0
0x018 SMC NFC Address Cycle Zero Register SMC_ADDR Read-write 0x0
0x01C SMC Bank Address Register SMC_BANK Read-write 0x0
0x020 SMC ECC Control Register SMC_ECC_CTRL Write-only 0x0
0x024 SMC ECC Mode Register SMC_ECC_MD Read-write 0x0
0x028 SMC ECC Status 1 Register SMC_ECC_SR1 Read-only 0x0
0x02C SMC ECC Parity 0 Register SMC_ECC_PR0 Read-only 0x0
0x030 SMC ECC parity 1 Register SMC_ECC_PR1 Read-only 0x0
0x034 SMC ECC status 2 Register SMC_ECC_SR2 Read-only 0x0
0x038 SMC ECC parity 2 Register SMC_ECC_PR2 Read-only 0x0
0x03C SMC ECC parity 3 Register SMC_ECC_PR3 Read-only 0x0
0x040 SMC ECC parity 4 Register SMC_ECC_PR4 Read-only 0x0
0x044 SMC ECC parity 5 Register SMC_ECC_PR5 Read-only 0x0
0x048 SMC ECC parity 6 Register SMC_ECC_PR6 Read-only 0x0
0x04C SMC ECC parity 7 Register SMC_ECC_PR7 Read-only 0x0
0x050 SMC ECC parity 8 Register SMC_ECC_PR8 Read-only 0x0
0x054 SMC ECC parity 9 Register SMC_ECC_PR9 Read-only 0x0
0x058 SMC ECC parity 10 Register SMC_ECC_PR10 Read-only 0x0
0x05C SMC ECC parity 11 Register SMC_ECC_PR11 Read-only 0x0
0x060 SMC ECC parity 12 Register SMC_ECC_PR12 Read-only 0x0
0x064 SMC ECC parity 13 Register SMC_ECC_PR13 Read-only 0x0
0x068 SMC ECC parity 14 Register SMC_ECC_PR14 Read-only 0x0
0x06C SMC ECC parity 15 Register SMC_ECC_PR15 Read-only 0x0
0x14*CS_number+0x070 SMC SETUP Register SMC_SETUP Read-write 0x01010101
0x14*CS_number+0x074 SMC PULSE Register SMC_PULSE Read-write 0x01010101
0x14*CS_number+0x078 SMC CYCLE Register SMC_CYCLE Read-write 0x00030003
0x14*CS_number+0x7C SMC TIMINGS Register SMC_TIMINGS Read-write 0x00000000
0x14*CS_number+0x80 SMC MODE Register SMC_MODE Read-write 0x10000003
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0x110 SMC OCMS MODE Register SMC_OCMS Read-write 0x0
0x114 SMC KEY1 Register SMC_KEY1 Write-only 0x0
0x118 SMC KEY2 Register SMC_KEY2 Write-only 0x0
0x1E4 Write Protection Control Register SMC_WPCR Write-only 0x0
0x1E8 Write Protection Status Register SMC_WPSR Read-only 0x0
0x1FC Reserved – – –
Table 25-11. Register Mapping (Continued)
Offset Register Name Access Reset
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25.18.1 SMC NFC Configuration Register
Name: SMC_CFG
Address: 0x400E0000
Access: Read-write
Reset: 0x00000000
• PAGESIZE
This field defines the page size of the NAND Flash device.
• WSPARE: Write Spare Area
0: The NFC skips the spare area in write mode.
1: The NFC writes both main area and spare area in write mode.
• RSPARE: Read Spare Area
0: The NFC skips the spare area in read mode.
1: The NFC reads both main area and spare area in read mode.
• EDGECTRL: Rising/Falling Edge Detection Control
0: Rising edge is detected.
1: Falling edge is detected.
• RBEDGE: Ready/Busy Signal Edge Detection
0: When set to zero, RB_EDGE fields indicate the level of the Ready/Busy lines.
1: When set to one, RB_EDGE fields indicate only transition on Ready/Busy lines.
• DTOCYC: Data Timeout Cycle Number
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– DTOMUL DTOCYC
15 14 13 12 11 10 9 8
– – RBEDGE EDGECTRL – – RSPARE WSPARE
76543210
–––––– PAGESIZE
Value Name Description
0 PS512_16 Main area 512 Bytes + Spare area 16 Bytes = 528 Bytes
1 PS1024_32 Main area 1024 Bytes + Spare area 32 Bytes = 1056 Bytes
2 PS2048_64 Main area 2048 Bytes + Spare area 64 Bytes = 2112 Bytes
3 PS4096_128 Main area 4096 Bytes + Spare area 128 Bytes = 4224 Bytes
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• DTOMUL: Data Timeout Multiplier
These fields determine the maximum number of Master Clock cycles that the SMC waits until the detection of a rising edge
on Ready/Busy signal.
Multiplier is defined by DTOMUL as shown in the following table:
If the data timeout set by DTOCYC and DTOMUL has been exceeded, the Data Timeout Error flag (DTOE) in the SMC
Status Register (SMC_SR) raises.
Value Name Description
0X1DTOCYC
1 X16 DTOCYC x 16
2 X128 DTOCYC x 128
3 X256 DTOCYC x 256
4 X1024 DTOCYC x 1024
5 X4096 DTOCYC x 4096
6 X65536 DTOCYC x 65536
7 X1048576 DTOCYC x 1048576
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25.18.2 SMC NFC Control Register
Name: SMC_CTRL
Address: 0x400E0004
Access: Write-only
Reset: 0x00000000
• NFCEN: NAND Flash Controller Enable
• NFCDIS: NAND Flash Controller Disable
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––NFCDISNFCEN
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25.18.3 SMC NFC Status Register
Name: SMC_SR
Address: 0x400E0008
Access: Read-only
Reset: 0x00000000
• SMCSTS: NAND Flash Controller status (this field cannot be reset)
0: NAND Flash Controller is disabled.
1: NAND Flash Controller is enabled.
• RB_RISE: Selected Ready Busy Rising Edge Detected
When set to one, this flag indicates that a rising edge on Ready/Busy Line has been detected. This flag is reset after a sta-
tus read operation. The Ready/Busy line selected is the decoding of the set NFCCSID, RBNSEL fields.
• RB_FALL: Selected Ready Busy Falling Edge Detected
When set to one, this flag indicates that a falling edge on Ready/Busy Line has been detected. This flag is reset after a sta-
tus read operation. The Ready/Busy line is selected through the decoding of the set NFCSID, RBNSEL fields.
• NFCBUSY: NFC Busy (this field cannot be reset)
When set to one this flag indicates that the Controller is activated and accesses the memory device.
• NFCWR: NFC Write/Read Operation (this field cannot be reset)
When a command is issued, this field indicates the current Read or Write Operation. This field can be manually updated
with the use of the SMC_CTRL register.
• NFCSID: NFC Chip Select ID (this field cannot be reset)
When a command is issued, this field indicates the value of the targeted chip select. This field can be manually updated
with the use of the SMC_CTRL register.
• XFRDONE: NFC Data Transfer Terminated
When set to one, this flag indicates that the NFC has terminated the Data Transfer. This flag is reset after a status read
operation.
• CMDDONE: Command Done
When set to one, this flag indicates that the NFC has terminated the Command. This flag is reset after a status read
operation.
31 30 29 28 27 26 25 24
–––––––RB_EDGE0
23 22 21 20 19 18 17 16
NFCASE AWB UNDEF DTOE – – CMDDONE XFRDONE
15 14 13 12 11 10 9 8
– NFCSID NFCWR – – NFCBUSY
76543210
– – RB_FALL RB_RISE – – – SMCSTS
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• DTOE: Data Timeout Error
When set to one this flag indicates that the Data timeout set be by DTOMUL and DTOCYC has been exceeded. This flag
is reset after a status read operation.
• UNDEF: Undefined Area Error
When set to one this flag indicates that the processor performed an access in an undefined memory area. This flag is reset
after a status read operation.
• AWB: Accessing While Busy
If set to one this flag indicates that an AHB master has performed an access during the busy phase. This flag is reset after
a status read operation.
• NFCASE: NFC Access Size Error
If set to one, this flag indicates that an illegal access has been detected in the NFC Memory Area. Only Word Access is
allowed within the NFC memory area. This flag is reset after a status read operation.
• RB_EDGEx: Ready/Busy Line x Edge Detected
If set to one, this flag indicates that an edge has been detected on the Ready/Busy Line x. Depending on the EDGE CTRL
field located in the SMC_MODE register, only rising or falling edge is detected. This flag is reset after a status read
operation.
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25.18.4 SMC NFC Interrupt Enable Register
Name: SMC_IER
Address: 0x400E000C
Access: Write-only
Reset: 0x00000000
• RB_RISE: Ready Busy Rising Edge Detection Interrupt Enable
• RB_FALL: Ready Busy Falling Edge Detection Interrupt Enable
• XFRDONE: Transfer Done Interrupt Enable
• CMDDONE: Command Done Interrupt Enable
• DTOE: Data Timeout Error Interrupt Enable
• UNDEF: Undefined Area Access Interrupt Enable
• AWB: Accessing While Busy Interrupt Enable
• NFCASE: NFC Access Size Error Interrupt Enable
• RB_EDGEx: Ready/Busy Line x Interrupt Enable
31 30 29 28 27 26 25 24
–––––––RB_EDGE0
23 22 21 20 19 18 17 16
NFCASE AWB UNDEF DTOE – – CMDDONE XFRDONE
15 14 13 12 11 10 9 8
––––––––
76543210
––RB_FALLRB_RISE––––
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25.18.5 SMC NFC Interrupt Disable Register
Name: SMC_IDR
Address: 0x400E0010
Access: Write-only
Reset: 0x00000000
• RB_RISE: Ready Busy Rising Edge Detection Interrupt Disable
• RB_FALL: Ready Busy Falling Edge Detection Interrupt Disable
• XFRDONE: Transfer Done Interrupt Disable
• CMDDONE: Command Done Interrupt Disable
• DTOE: Data Timeout Error Interrupt Disable
• UNDEF: Undefined Area Access Interrupt Disable
• AWB: Accessing While Busy Interrupt Disable
• NFCASE: NFC Access Size Error Interrupt Disable
• RB_EDGEx: Ready/Busy Line x Interrupt Disable
31 30 29 28 27 26 25 24
–––––––RB_EDGE0
23 22 21 20 19 18 17 16
NFCASE AWB UNDEF DTOE – – CMDDONE XFRDONE
15 14 13 12 11 10 9 8
––––––––
76543210
––RB_FALLRB_RISE––––
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25.18.6 SMC NFC Interrupt Mask Register
Name: SMC_IMR
Address: 0x400E0014
Access: Read-only
Reset: 0x00000000
• RB_RISE: Ready Busy Rising Edge Detection Interrupt Mask
• RB_FALL: Ready Busy Falling Edge Detection Interrupt Mask
• XFRDONE: Transfer Done Interrupt Mask
• CMDDONE: Command Done Interrupt Mask
• DTOE: Data Timeout Error Interrupt Mask
• UNDEF: Undefined Area Access Interrupt Mask5
• AWB: Accessing While Busy Interrupt Mask
• NFCASE: NFC Access Size Error Interrupt Mask
• RB_EDGEx: Ready/Busy Line x Interrupt Mask
31 30 29 28 27 26 25 24
–––––––RB_EDGE0
23 22 21 20 19 18 17 16
NFCASE AWB UNDEF DTOE – – CMDDONE XFRDONE
15 14 13 12 11 10 9 8
––––––––
76543210
––RB_FALLRB_RISE––––
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
25.18.7 SMC NFC Address Cycle Zero Register
Name: SMC_ADDR
Address: 0x400E0018
Access: Read-Write
Reset: 0x00000000
• ADDR_CYCLE0: NAND Flash Array Address cycle 0
When 5 address cycles are used, ADDR_CYCLE0 is the first byte written to NAND Flash (used by the NFC).
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ADDR_CYCLE0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
476
25.18.8 SMC NFC Bank Register
Name: SMC_BANK
Address: 0x400E001C
Access: Read-write
Reset: 0x00000000
• BANK: Bank Identifier
Number of the Bank used
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––– BANK
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477
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
25.18.9 SMC ECC Control Register
Name: SMC_ECC_CTRL
Address: 0x400E0020
Access: Write-only
Reset: 0x00000000
• RST: Reset ECC
• SWRST: Software Reset
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––SWRSTRST
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
478
25.18.10 SMC ECC MODE Register
Name: SMC_ECC_MD
Address: 0x400E0024
Access: Read-write
Reset: 0x00000000
• ECC_PAGESIZE
This field defines the page size of the NAND Flash device.
• TYPCORREC: Type of Correction
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– – TYPCORREC – – ECC_PAGESIZE
Value Name Description
0 PS512_16 Main area 512 Bytes + Spare area 16 Bytes = 528 Bytes
1 PS1024_32 Main area 1024 Bytes + Spare area 32 Bytes = 1056 Bytes
2 PS2048_64 Main area 2048 Bytes + Spare area 64 Bytes = 2112 Bytes
3 PS4096_128 Main area 4096 Bytes + Spare area 128 Bytes = 4224 Bytes
Value Name Description
0CPAGE
1 bit correction for a page of 512/1024/2048/4096 Bytes
(for 8 or 16-bit NAND Flash)
1 C256B 1 bit correction for 256 Bytes of data for a page of 512/2048/4096 bytes
(for 8-bit NAND Flash only)
2 C512B 1 bit correction for 512 Bytes of data for a page of 512/2048/4096 bytes
(for 8-bit NAND Flash only)
479
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
25.18.11 SMC ECC Status Register 1
Name: SMC_ECC_SR1
Address: 0x400E0028
Access: Read-only
Reset: 0x00000000
• RECERR0: Recoverable Error
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected.
• ECCERR0: ECC Error
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
If TYPECORRECT = 0, read both ECC Parity 0 and ECC Parity 1 registers, the error occurred at the location which con-
tains a 1 in the least significant 16 bits; else read ECC Parity 0 register, the error occurred at the location which contains a
1 in the least significant 24 bits.
• MULERR0: Multiple Error
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR1: Recoverable Error in the page between the 256th and the 511th bytes or the 512nd and the 1023rd
bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected.
• ECCERR1: ECC Error in the page between the 256th and the 511th bytes or between the 512nd and the 1023rd
bytes
Fixed to 0 if TYPECORREC = 0
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 1 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
31 30 29 28 27 26 25 24
– ECCERR7 ECCERR7 RECERR7 – ECCERR6 ECCERR6 RECERR6
23 22 21 20 19 18 17 16
– ECCERR5 ECCERR5 RECERR5 – ECCERR4 ECCERR4 RECERR4
15 14 13 12 11 10 9 8
– MULERR3 ECCERR3 RECERR3 – MULERR2 ECCERR2 RECERR2
76543210
– MULERR1 ECCERR1 RECERR1 – ECCERR0 ECCERR0 RECERR0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
480
• MULERR1: Multiple Error in the page between the 256th and the 511th bytes or between the 512nd and the
1023rd bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR2: Recoverable Error in the page between the 512nd and the 767th bytes or between the 1024th and the
1535th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise, multiple uncorrected errors
were detected.
• ECCERR2: ECC Error in the page between the 512nd and the 767th bytes or between the 1024th and the 1535th
bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 2 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR2: Multiple Error in the page between the 512nd and the 767th bytes or between the 1024th and the
1535th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR3: Recoverable Error in the page between the 768th and the 1023rd bytes or between the 1536th and
the 2047th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected.
• ECCERR3: ECC Error in the page between the 768th and the 1023rd bytes or between the 1536th and the 2047th
bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 3 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR3: Multiple Error in the page between the 768th and the 1023rd bytes or between the 1536th and the
2047th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
AtmeL
481
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• RECERR4: Recoverable Error in the page between the 1024th and the 1279th bytes or between the 2048th and
the 2559th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected.
• ECCERR4: ECC Error in the page between the 1024th and the 1279th bytes or between the 2048th and the
2559th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 4 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR4: Multiple Error in the page between the 1024th and the 1279th bytes or between the 2048th and the
2559th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR5: Recoverable Error in the page between the 1280th and the 1535th bytes or between the 2560th and
the 3071st bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected
• ECCERR5: ECC Error in the page between the 1280th and the 1535th bytes or between the 2560th and the
3071st bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 5 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR5: Multiple Error in the page between the 1280th and the 1535th bytes or between the 2560th and the
3071st bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
482
• RECERR6: Recoverable Error in the page between the 1536th and the 1791st bytes or between the 3072nd and
the 3583rd bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected.
• ECCERR6: ECC Error in the page between the 1536th and the 1791st bytes or between the 3072nd and the
3583rd bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 6 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR6: Multiple Error in the page between the 1536th and the 1791st bytes or between the 3072nd and the
3583rd bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR7: Recoverable Error in the page between the 1792nd and the 2047th bytes or between the 3584th and
the 4095th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise, multiple uncorrected errors
were detected.
• ECCERR7: ECC Error in the page between the 1792nd and the 2047th bytes or between the 3584th and the
4095th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 7 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR7: Multiple Error in the page between the 1792nd and the 2047th bytes or between the 3584th and the
4095th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
483
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
25.18.12 SMC ECC Status Register 2
Name: SMC_ECC_SR2
Address: 0x400E0034
Access: Read-only
Reset: 0x00000000
• RECERR8: Recoverable Error in the page between the 2048th and the 2303rd bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected
• ECCERR8: ECC Error in the page between the 2048th and the 2303rd bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 8 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR8: Multiple Error in the page between the 2048th and the 2303rd bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR9: Recoverable Error in the page between the 2304th and the 2559th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected.
• ECCERR9: ECC Error in the page between the 2304th and the 2559th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 9 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
31 30 29 28 27 26 25 24
– ECCERR15 ECCERR15 RECERR15 – ECCERR14 ECCERR14 RECERR14
23 22 21 20 19 18 17 16
– ECCERR13 ECCERR13 RECERR13 – ECCERR12 ECCERR12 RECERR12
15 14 13 12 11 10 9 8
– MULERR11 ECCERR11 RECERR11 – MULERR10 ECCERR10 RECERR10
76543210
– MULERR9 ECCERR9 RECERR9 – ECCERR8 ECCERR8 RECERR8
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
484
• MULERR9: Multiple Error in the page between the 2304th and the 2559th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR10: Recoverable Error in the page between the 2560th and the 2815th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise, multiple uncorrected errors
were detected.
• ECCERR10: ECC Error in the page between the 2560th and the 2815th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 10 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR10: Multiple Error in the page between the 2560th and the 2815th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR11: Recoverable Error in the page between the 2816th and the 3071st bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise, multiple uncorrected errors
were detected
• ECCERR11: ECC Error in the page between the 2816th and the 3071st bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 11 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR11: Multiple Error in the page between the 2816th and the 3071st bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR12: Recoverable Error in the page between the 3072nd and the 3327th bytes
Fixed to 0 if TYPECORREC = 0
0: No Errors Detected
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected
AtmeL
485
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• ECCERR12: ECC Error in the page between the 3072nd and the 3327th bytes
Fixed to 0 if TYPECORREC = 0
0: No Errors Detected
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 12 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR12: Multiple Error in the page between the 3072nd and the 3327th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR13: Recoverable Error in the page between the 3328th and the 3583rd bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected.
• ECCERR13: ECC Error in the page between the 3328th and the 3583rd bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 13 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR13: Multiple Error in the page between the 3328th and the 3583rd bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
• RECERR14: Recoverable Error in the page between the 3584th and the 3839th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise, multiple uncorrected errors
were detected.
• ECCERR14: ECC Error in the page between the 3584th and the 3839th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 14 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR14: Multiple Error in the page between the 3584th and the 3839th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
486
• RECERR15: Recoverable Error in the page between the 3840th and the 4095th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise, multiple uncorrected errors
were detected.
• ECCERR15: ECC Error in the page between the 3840th and the 4095th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Errors Detected.
1: A single bit error occurred in the ECC bytes.
Read ECC Parity 15 register, the error occurred at the location which contains a 1 in the least significant 24 bits.
• MULERR15: Multiple Error in the page between the 3840th and the 4095th bytes
Fixed to 0 if TYPECORREC = 0.
0: No Multiple Errors Detected.
1: Multiple Errors Detected.
487
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
25.18.13 SMC ECC Parity Register 0 for a Page of 512/1024/2048/4096 Bytes
Name: SMC_ECC_PR0
Address: 0x400E002C
Access: Read-only
Reset: 0x00000000
Once the entire main area of a page is written with data, the register content must be stored at any free location of the
spare area.
• BITADDR: Bit Address
During a page read, this value contains the corrupted bit offset where an error occurred, if a single error was detected. If
multiple errors were detected, this value is meaningless.
• WORDADDR: Word Address
During a page read, this value contains the word address (8-bit or 16-bit word depending on the memory plane organiza-
tion).where an error occurred, if a single error was detected. If multiple errors were detected, this value is meaningless.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
WORDADDR
76543210
WORDADDR BITADDR
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
488
25.18.14 SMC ECC Parity Register 1 for a Page of 512/1024/2048/4096 Bytes
Name: SMC_ECC_PR1
Address: 0x400E0030
Access: Read-only
Reset: 0x00000000
•NPARITY: Parity N
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
NPARITY
76543210
NPARITY
489
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
25.18.15 SMC ECC Parity Registers for 1 ECC per 512 Bytes for a Page of 512/2048/4096 Bytes, 9-bit Word
Name: SMC_ECC_PRx [x=0..7] (W9BIT)
Address: 0x400E0038 [2] .. 0x400E006C [15]
Access: Read-only
Reset: 0x00000000
Once the entire main area of a page is written with data, the register content must be stored at any free location of the
spare area.
• BITADDR: Corrupted Bit Address in the Page between (i x 512) and ((i + 1) x 512) - 1) Bytes
During a page read, this value contains the corrupted bit offset where an error occurred, if a single error was detected. If
multiple errors were detected, this value is meaningless.
• WORDADDR: Corrupted Word Address in the Page between (i x 512) and ((i + 1) x 512) - 1) Bytes
During a page read, this value contains the word address (9-bit word) where an error occurred, if a single error was
detected. If multiple errors were detected, this value is meaningless.
•NPARITY: Parity N
31 30 29 28 27 26 25 24
– – ––––––
23 22 21 20 19 18 17 16
NPARITY
15 14 13 12 11 10 9 8
NPARITY WORDADDR
7 6 543210
WORDADDR BITADDR
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
490
25.18.16 SMC ECC Parity Registers for 1 ECC per 256 Bytes for a Page of 512/2048/4096 Bytes, 8-bit Word
Name: SMC_ECC_PRx [x=0..15] (W8BIT)
Address: 0x400E0038 [2] .. 0x400E006C [15]
Access: Read-only
Reset: 0x00000000
Once the entire main area of a page is written with data, the register content must be stored at any free location of the
spare area.
• BITADDR: Corrupted Bit Address in the page between (i x 256) and ((i + 1) x 512) - 1) Bytes
• During a page read, this value contains the corrupted bit offset where an error occurred, if a single error was
detected. If multiple errors were detected, this value is meaningless.
• WORDADDR: Corrupted Word Address in the page between (i x 256) and ((i + 1) x 512) - 1) Bytes
During a page read, this value contains the word address (8-bit word) where an error occurred, if a single error was
detected. If multiple errors were detected, this value is meaningless.
•NPARITY: Parity N
31 30 29 28 27 26 25 24
– – ––––––
23 22 21 20 19 18 17 16
0NPARITY
15 14 13 12 11 10 9 8
NPARITY 0 WORDADDR
7 6 543210
WORDADDR BITADDR
AtmeL
491
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
25.18.17 SMC Setup Register
Name: SMC_SETUPx [x=0..7]
Address: 0x400E0070 [0], 0x400E0084 [1], 0x400E0098 [2], 0x400E00AC [3], 0x400E00C0 [4], 0x400E00D4 [5],
0x400E00E8 [6], 0x400E00FC [7]
Access: Write-only
Reset: 0x00000000
• NWE_SETUP: NWE Setup Length
The NWE signal setup length is defined as:
NWE setup length = (128 * NWE_SETUP[5] + NWE_SETUP[4:0]) clock cycles.
• NCS_WR_SETUP: NCS Setup length in Write access
In write access, the NCS signal setup length is defined as:
NCS setup length = (128 * NCS_WR_SETUP[5] + NCS_WR_SETUP[4:0]) clock cycles.
• NRD_SETUP: NRD Setup length
The NRD signal setup length is defined as:
NRD setup length = (128 * NRD_SETUP[5] + NRD_SETUP[4:0]) clock cycles.
• NCS_RD_SETUP: NCS Setup length in Read access
In Read access, the NCS signal setup length is defined as:
NCS setup length = (128 * NCS_RD_SETUP[5] + NCS_RD_SETUP[4:0]) clock cycles.
31 30 29 28 27 26 25 24
– – NCS_RD_SETUP
23 22 21 20 19 18 17 16
– – NRD_SETUP
15 14 13 12 11 10 9 8
– – NCS_WR_SETUP
76543210
– – NWE_SETUP
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
492
25.18.18 SMC Pulse Register
Name: SMC_PULSEx [x=0..7]
Address: 0x400E0074 [0], 0x400E0088 [1], 0x400E009C [2], 0x400E00B0 [3], 0x400E00C4 [4], 0x400E00D8 [5],
0x400E00EC [6], 0x400E0100 [7]
Access: Write-only
Reset: 0x00000000
• NWE_PULSE: NWE Pulse Length
The NWE signal pulse length is defined as:
NWE pulse length = (256 * NWE_PULSE[6]+NWE_PULSE[5:0]) clock cycles.
The NWE pulse must be at least one clock cycle.
• NCS_WR_PULSE: NCS Pulse Length in WRITE Access
In Write access, The NCS signal pulse length is defined as:
NCS pulse length = (256 * NCS_WR_PULSE[6] + NCS_WR_PULSE[5:0]) clock cycles.
the NCS pulse must be at least one clock cycle.
• NRD_PULSE: NRD Pulse Length
The NRD signal pulse length is defined as:
NRD pulse length = (256 * NRD_PULSE[6] + NRD_PULSE[5:0]) clock cycles.
The NRD pulse width must be as least 1 clock cycle.
• NCS_RD_PULSE: NCS Pulse Length in READ Access
In READ mode, The NCS signal pulse length is defined as:
NCS pulse length = (256 * NCS_RD_PULSE[6] + NCS_RD_PULSE[5:0]) clock cycles.
31 30 29 28 27 26 25 24
– – NCS_RD_PULSE
23 22 21 20 19 18 17 16
– – NRD_PULSE
15 14 13 12 11 10 9 8
– – NCS_WR_PULSE
76543210
– – NWE_PULSE
AtmeL
493
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
25.18.19 SMC Cycle Register
Name: SMC_CYCLEx [x=0..7]
Address: 0x400E0078 [0], 0x400E008C [1], 0x400E00A0 [2], 0x400E00B4 [3], 0x400E00C8 [4], 0x400E00DC [5],
0x400E00F0 [6], 0x400E0104 [7]
Access: Read-write
Reset: 0x00000000
• NWE_CYCLE: Total Write Cycle Length
The total write cycle length is the total duration in clock cycles of the write cycle. It is equal to the sum of the setup, pulse
and hold steps of the NWE and NCS signals. It is defined as:
Write cycle length = (NWE_CYCLE[8:7] * 256) + NWE_CYCLE[6:0] clock cycles.
• NRD_CYCLE: Total Read Cycle Length
The total read cycle length is the total duration in clock cycles of the read cycle. It is equal to the sum of the setup, pulse
and hold steps of the NRD and NCS signals. It is defined as:
Read cycle length = (NRD_CYCLE[8:7] * 256) + NRD_CYCLE[6:0] clock cycles.
31 30 29 28 27 26 25 24
–––––––NRD_CYCLE
23 22 21 20 19 18 17 16
NRD_CYCLE
15 14 13 12 11 10 9 8
–––––––NWE_CYCLE
76543210
NWE_CYCLE
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25.18.20 SMC Timings Register
Name: SMC_TIMINGSx [x=0..7]
Address: 0x400E007C [0], 0x400E0090 [1], 0x400E00A4 [2], 0x400E00B8 [3], 0x400E00CC [4], 0x400E00E0 [5],
0x400E00F4 [6], 0x400E0108 [7]
Access: Read-write
Reset: 0x00000000
• TCLR: CLE to REN Low Delay
Command Latch Enable falling edge to Read Enable falling edge timing.
Latch Enable Falling to Read Enable Falling = (TCLR[3] * 64) + TCLR[2:0] clock cycles.
• TADL: ALE to Data Start
Last address latch cycle to the first rising edge of WEN for data input.
Last address latch to first rising edge of WEN = (TADL[3] * 64) + TADL[2:0] clock cycles.
• TAR: ALE to REN Low Delay
Address Latch Enable falling edge to Read Enable falling edge timing.
Address Latch Enable to Read Enable = (TAR[3] * 64) + TAR[2:0] clock cycles.
• OCMS: Off Chip Memory Scrambling Enable
When set to one, the memory scrambling is activated.
• TRR: Ready to REN Low Delay
Ready/Busy signal to Read Enable falling edge timing.
Read to REN = (TRR[3] * 64) + TRR[2:0] clock cycles.
• TWB: WEN High to REN to Busy
Write Enable rising edge to Ready/Busy falling edge timing.
Write Enable to Read/Busy = (TWB[3] * 64) + TWB[2:0] clock cycles.
• RBNSEL: Ready/Busy Line Selection
This field indicates the selected Ready/Busy Line from the RBN bundle.
31 30 29 28 27 26 25 24
NFSEL RBNSEL TWB
23 22 21 20 19 18 17 16
–––– TRR
15 14 13 12 11 10 9 8
–––OCMS TAR
76543210
TADL TCLR
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• NFSEL: NAND Flash Selection
If this bit is set to one, the chip select is assigned to NAND Flash write enable and read enable lines drive the Error Cor-
recting Code module.
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25.18.21 SMC Mode Register
Name: SMC_MODEx [x=0..7]
Address: 0x400E0080 [0], 0x400E0094 [1], 0x400E00A8 [2], 0x400E00BC [3], 0x400E00D0 [4], 0x400E00E4 [5],
0x400E00F8 [6], 0x400E010C [7]
Access: Read-write
Reset: 0x00000000
• READ_MODE
1: The Read operation is controlled by the NRD signal.
0: The Read operation is controlled by the NCS signal.
•WRITE_MODE
1: The Write operation is controlled by the NWE signal.
0: The Write operation is controller by the NCS signal.
• EXNW_MODE: NWAIT Mode
The NWAIT signal is used to extend the current read or write signal. It is only taken into account during the pulse phase
Read and Write controlling signal. When the use of NWAIT is enabled, at least one cycle hold duration must be pro-
grammed for the read and write controlling signal
•Disabled Mode: The NWAIT input signal is ignored on the corresponding Chip Select.
• Frozen Mode: If asserted, the NWAIT signal freezes the current read or write cycle. After deassertion, the read/write
cycle is resumed from the point where it was stopped.
•Ready Mode: The NWAIT signal indicates the availability of the external device at the end of the pulse of the controlling
read or write signal, to complete the access. If high, the access normally completes. If low, the access is extended until
NWAIT returns high.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– – – TDF_MODE TDF_CYCLES
15 14 13 12 11 10 9 8
–––DBW–––BAT
76543210
– – EXNW_MODE – – WRITE_MODE READ_MODE
Value Name Description
0 DISABLED Disabled
1 Reserved
2 FROZEN Frozen Mode
3 READY Ready Mode
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• BAT: Byte Access Type
This field is used only if DBW defines a 16-bit data bus.
• 1: Byte write access type:
– Write operation is controlled using NCS, NWR0, NWR1.
–Read operation is controlled using NCS and NRD.
• 0: Byte select access type:
– Write operation is controlled using NCS, NWE, NBS0, NBS1.
–Read operation is controlled using NCS, NRD, NBS0, NBS1.
• DBW: Data Bus Width
• TDF_CYCLES: Data Float Time
This field gives the integer number of clock cycles required by the external device to release the data after the rising edge
of the read controlling signal. The SMC always provide one full cycle of bus turnaround after the TDF_CYCLES period. The
external bus cannot be used by another chip select during TDF_CYCLES + 1 cycles. From 0 up to 15 TDF_CYCLES can
be set.
• TDF_MODE: TDF Optimization
1: TDF optimization is enabled.
–The number of TDF wait states is optimized using the setup period of the next read/write access.
0: TDF optimization is disabled.
–The number of TDF wait states is inserted before the next access begins.
Value Name Description
0 BIT_8 8-bit bus
1 BIT_16 16-bit bus
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25.18.22 SMC OCMS Register
Name: SMC_OCMS
Address: 0x400E0110
Access: Read-write
Reset: 0x00000000
• SMSE: Static Memory Controller Scrambling Enable
0: Disable “Off Chip” Scrambling for SMC access.
1: Enable “Off Chip” Scrambling for SMC access. (If OCMS field is set to 1 in the relevant SMC_TIMINGS register.)
• SRSE: SRAM Scrambling Enable
0: Disable SRAM Scrambling for SRAM access.
1: Enable SRAM Scrambling for SRAM access. (If OCMS field is set to 1 in the relevant SMC_TIMINGS register.)
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––SRSESMSE
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25.18.23 SMC OCMS Key1 Register
Name: SMC_KEY1
Address: 0x400E0114
Access: Write Once
Reset: 0x00000000
• KEY1: Off Chip Memory Scrambling (OCMS) Key Part 1
When Off Chip Memory Scrambling is enabled by setting the SMC_OMCS and SMC_TIMINGS registers in accordance,
the data scrambling depends on KEY1 and KEY2 values.
31 30 29 28 27 26 25 24
KEY1
23 22 21 20 19 18 17 16
KEY1
15 14 13 12 11 10 9 8
KEY1
76543210
KEY1
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25.18.24 SMC OCMS Key2 Register
Name: SMC_KEY2
Address: 0x400E0118
Access: Write Once
Reset: 0x00000000
• KEY2: Off Chip Memory Scrambling (OCMS) Key Part 2
When Off Chip Memory Scrambling is enabled by setting the SMC_OMCS and SMC_TIMINGS registers in accordance,
the data scrambling depends on KEY2 and KEY1 values.
31 30 29 28 27 26 25 24
KEY2
23 22 21 20 19 18 17 16
KEY2
15 14 13 12 11 10 9 8
KEY2
76543210
KEY2
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25.18.25 SMC Write Protection Control
Name: SMC_WPCR
Address: 0x400E01E4
Access: Write-only
• WP_EN: Write Protection Enable
0: Disables the Write Protection if WP_KEY corresponds.
1: Enables the Write Protection if WP_KEY corresponds.
• WP_KEY: Write Protection KEY password
Should be written at value 0x534D43 (ASCII code for “SMC”). Writing any other value in this field has no effect.
31 30 29 28 27 26 25 24
WP_KEY
23 22 21 20 19 18 17 16
WP_KEY
15 14 13 12 11 10 9 8
WP_KEY
76543210
WP_EN
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25.18.26 SMC Write Protection Status
Name: SMC_WPSR
Address: 0x400E01E8
Access: Read-only
• WP_VS: Write Protection Violation Status
0: No Write Protect Violation has occurred since the last read of the SMC_WPSR register.
1: A Write Protect Violation has occurred since the last read of the SMC_WPSR register. If this violation is an unauthorized
attempt to write a protected register, the associated violation is reported into field WP_VSRC.
• WP_VSRC: Write Protection Violation SouRCe
WP_VSRC field Indicates the Register offset where the last violation occurred.
31 30 29 28 27 26 25 24
--------
23 22 21 20 19 18 17 16
WP_VSRC
15 14 13 12 11 10 9 8
WP_VSRC
76543210
---- WP_VS
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26. Peripheral DMA Controller (PDC)
26.1 Description
The Peripheral DMA Controller (PDC) transfers data between on-chip serial peripherals and the on- and/or off-chip
memories. The link between the PDC and a serial peripheral is operated by the AHB to APB bridge.
The user interface of each PDC channel is integrated into the user interface of the peripheral it serves. The user
interface of mono directional channels (receive only or transmit only), contains two 32-bit memory pointers and two
16-bit counters, one set (pointer, counter) for current transfer and one set (pointer, counter) for next transfer. The
bi-directional channel user interface contains four 32-bit memory pointers and four 16-bit counters. Each set
(pointer, counter) is used by current transmit, next transmit, current receive and next receive.
Using the PDC removes processor overhead by reducing its intervention during the transfer. This significantly
reduces the number of clock cycles required for a data transfer, which improves microcontroller performance.
To launch a transfer, the peripheral triggers its associated PDC channels by using transmit and receive signals.
When the programmed data is transferred, an end of transfer interrupt is generated by the peripheral itself.
26.2 Embedded Characteristics
Handles data transfer between peripherals and memories
Low bus arbitration overhead
̶One Master Clock cycle needed for a transfer from memory to peripheral
̶Two Master Clock cycles needed for a transfer from peripheral to memory
Next Pointer management for reducing interrupt latency requirement
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The Peripheral DMA Controller handles transfer requests from the channel according to the following priorities
(Low to High priorities):
Note: 1.Corresponds to 217-pin SAM3X8H. This device is not commercially available. Mounted only on the SAM3X-EK
evaluation kit.
Table 26-1. Peripheral DMA Controller
Instance Name Channel T/R 217 Pins(1) 144 Pins 100 Pins
DAC Transmit XXX
PWM Transmit XXX
TWI1 Transmit XXX
TWI0 Transmit XXX
USART3 Transmit XXN/A
USART2 Transmit XXX
USART1 Transmit XXX
USART0 Transmit X X X
UART Transmit X X X
ADC Receive XXX
TWI1 Receive XXX
TWI0 Receive XXX
USART3 Receive XXN/A
USART2 Receive XXX
USART1 Receive XXX
USART0 Receive XXX
UART Receive XXX
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26.3 Block Diagram
Figure 26-1. Block Diagram
PDC
FULL DUPLEX
PERIPHERAL
THR
RHR
PDC Channel A
PDC Channel B
Control
Status & Control
Control
PDC Channel C
HALF DUPLEX
PERIPHERAL
THR
Status & Control
RECEIVE or TRANSMIT
PERIPHERAL
RHR or THR
Control
Control
RHR
PDC Channel D
Status & Control
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26.4 Functional Description
26.4.1 Configuration
The PDC channel user interface enables the user to configure and control data transfers for each channel. The
user interface of each PDC channel is integrated into the associated peripheral user interface.
The user interface of a serial peripheral, whether it is full or half duplex, contains four 32-bit pointers (RPR, RNPR,
TPR, TNPR) and four 16-bit counter registers (RCR, RNCR, TCR, TNCR). However, the transmit and receive
parts of each type are programmed differently: the transmit and receive parts of a full duplex peripheral can be
programmed at the same time, whereas only one part (transmit or receive) of a half duplex peripheral can be
programmed at a time.
32-bit pointers define the access location in memory for current and next transfer, whether it is for read (transmit)
or write (receive). 16-bit counters define the size of current and next transfers. It is possible, at any moment, to
read the number of transfers left for each channel.
The PDC has dedicated status registers which indicate if the transfer is enabled or disabled for each channel. The
status for each channel is located in the associated peripheral status register. Transfers can be enabled and/or
disabled by setting TXTEN/TXTDIS and RXTEN/RXTDIS in the peripheral’s Transfer Control Register.
At the end of a transfer, the PDC channel sends status flags to its associated peripheral. These flags are visible in
the peripheral status register (ENDRX, ENDTX, RXBUFF, and TXBUFE). Refer to Section 26.4.3 and to the
associated peripheral user interface.
26.4.2 Memory Pointers
Each full duplex peripheral is connected to the PDC by a receive channel and a transmit channel. Both channels
have 32-bit memory pointers that point respectively to a receive area and to a transmit area in on- and/or off-chip
memory.
Each half duplex peripheral is connected to the PDC by a bidirectional channel. This channel has two 32-bit
memory pointers, one for current transfer and the other for next transfer. These pointers point to transmit or
receive data depending on the operating mode of the peripheral.
Depending on the type of transfer (byte, half-word or word), the memory pointer is incremented respectively by 1,
2 or 4 bytes.
If a memory pointer address changes in the middle of a transfer, the PDC channel continues operating using the
new address.
26.4.3 Transfer Counters
Each channel has two 16-bit counters, one for current transfer and the other one for next transfer. These counters
define the size of data to be transferred by the channel. The current transfer counter is decremented first as the
data addressed by current memory pointer starts to be transferred. When the current transfer counter reaches
zero, the channel checks its next transfer counter. If the value of next counter is zero, the channel stops
transferring data and sets the appropriate flag. But if the next counter value is greater then zero, the values of the
next pointer/next counter are copied into the current pointer/current counter and the channel resumes the transfer
whereas next pointer/next counter get zero/zero as values. At the end of this transfer the PDC channel sets the
appropriate flags in the Peripheral Status Register.
The following list gives an overview of how status register flags behave depending on the counters’ values:
ENDRX flag is set when the PERIPH_RCR register reaches zero.
RXBUFF flag is set when both PERIPH_RCR and PERIPH_RNCR reach zero.
ENDTX flag is set when the PERIPH_TCR register reaches zero.
TXBUFE flag is set when both PERIPH_TCR and PERIPH_TNCR reach zero.
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These status flags are described in the Peripheral Status Register.
26.4.4 Data Transfers
The serial peripheral triggers its associated PDC channels’ transfers using transmit enable (TXEN) and receive
enable (RXEN) flags in the transfer control register integrated in the peripheral’s user interface.
When the peripheral receives an external data, it sends a Receive Ready signal to its PDC receive channel which
then requests access to the Matrix. When access is granted, the PDC receive channel starts reading the
peripheral Receive Holding Register (RHR). The read data are stored in an internal buffer and then written to
memory.
When the peripheral is about to send data, it sends a Transmit Ready to its PDC transmit channel which then
requests access to the Matrix. When access is granted, the PDC transmit channel reads data from memory and
puts them to Transmit Holding Register (THR) of its associated peripheral. The same peripheral sends data
according to its mechanism.
26.4.5 PDC Flags and Peripheral Status Register
Each peripheral connected to the PDC sends out receive ready and transmit ready flags and the PDC sends back
flags to the peripheral. All these flags are only visible in the Peripheral Status Register.
Depending on the type of peripheral, half or full duplex, the flags belong to either one single channel or two
different channels.
26.4.5.1 Receive Transfer End
This flag is set when PERIPH_RCR register reaches zero and the last data has been transferred to memory.
It is reset by writing a non zero value in PERIPH_RCR or PERIPH_RNCR.
26.4.5.2 Transmit Transfer End
This flag is set when PERIPH_TCR register reaches zero and the last data has been written into peripheral THR.
It is reset by writing a non zero value in PERIPH_TCR or PERIPH_TNCR.
26.4.5.3 Receive Buffer Full
This flag is set when PERIPH_RCR register reaches zero with PERIPH_RNCR also set to zero and the last data
has been transferred to memory.
It is reset by writing a non zero value in PERIPH_TCR or PERIPH_TNCR.
26.4.5.4 Transmit Buffer Empty
This flag is set when PERIPH_TCR register reaches zero with PERIPH_TNCR also set to zero and the last data
has been written into peripheral THR.
It is reset by writing a non zero value in PERIPH_TCR or PERIPH_TNCR.
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26.5 Peripheral DMA Controller (PDC) User Interface
Note: 1. PERIPH: Ten registers are mapped in the peripheral memory space at the same offset. These can be defined by the user
according to the function and the desired peripheral.)
Table 26-2. Register Mapping
Offset Register Name Access Reset
0x100 Receive Pointer Register PERIPH(1)_RPR Read-write 0
0x104 Receive Counter Register PERIPH_RCR Read-write 0
0x108Transmit Pointer Register PERIPH_TPR Read-write 0
0x10C Transmit Counter Register PERIPH_TCR Read-write 0
0x110 Receive Next Pointer Register PERIPH_RNPR Read-write 0
0x114 Receive Next Counter Register PERIPH_RNCR Read-write 0
0x118Transmit Next Pointer Register PERIPH_TNPR Read-write 0
0x11C Transmit Next Counter Register PERIPH_TNCR Read-write 0
0x120 Transfer Control Register PERIPH_PTCR Write-only 0
0x124 Transfer Status Register PERIPH_PTSRRead-only 0
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26.5.1 Receive Pointer Register
Name: PERIPH_RPR
Access: Read-write
• RXPTR: Receive Pointer Register
RXPTR must be set to receive buffer address.
When a half duplex peripheral is connected to the PDC, RXPTR = TXPTR.
3130292827 26 25 24
RXPTR
2322 21 20 19 1817 16
RXPTR
15 14 1312 11 10 9 8
RXPTR
76543210
RXPTR
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26.5.2 Receive Counter Register
Name: PERIPH_RCR
Access: Read-write
• RXCTR: Receive Counter Register
RXCTR must be set to receive buffer size.
When a half duplex peripheral is connected to the PDC, RXCTR = TXCTR.
0: Stops peripheral data transfer to the receiver
1 - 65535: Starts peripheral data transfer if corresponding channel is active
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
RXCTR
76543210
RXCTR
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26.5.3 Transmit Pointer Register
Name: PERIPH_TPR
Access: Read-write
• TXPTR: Transmit Counter Register
TXPTR must be set to transmit buffer address.
When a half duplex peripheral is connected to the PDC, RXPTR = TXPTR.
3130292827 26 25 24
TXPTR
2322 21 20 19 1817 16
TXPTR
15 14 1312 11 10 9 8
TXPTR
76543210
TXPTR
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26.5.4 Transmit Counter Register
Name: PERIPH_TCR
Access: Read-write
• TXCTR: Transmit Counter Register
TXCTR must be set to transmit buffer size.
When a half duplex peripheral is connected to the PDC, RXCTR = TXCTR.
0: Stops peripheral data transfer to the transmitter
1- 65535: Starts peripheral data transfer if corresponding channel is active
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
TXCTR
76543210
TXCTR
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26.5.5 Receive Next Pointer Register
Name: PERIPH_RNPR
Access: Read-write
• RXNPTR: Receive Next Pointer
RXNPTR contains next receive buffer address.
When a half duplex peripheral is connected to the PDC, RXNPTR = TXNPTR.
3130292827 26 25 24
RXNPTR
2322 21 20 19 1817 16
RXNPTR
15 14 1312 11 10 9 8
RXNPTR
76543210
RXNPTR
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26.5.6 Receive Next Counter Register
Name: PERIPH_RNCR
Access: Read-write
• RXNCTR: Receive Next Counter
RXNCTR contains next receive buffer size.
When a half duplex peripheral is connected to the PDC, RXNCTR = TXNCTR.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
RXNCTR
76543210
RXNCTR
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26.5.7 Transmit Next Pointer Register
Name: PERIPH_TNPR
Access: Read-write
• TXNPTR: Transmit Next Pointer
TXNPTR contains next transmit buffer address.
When a half duplex peripheral is connected to the PDC, RXNPTR = TXNPTR.
3130292827 26 25 24
TXNPTR
2322 21 20 19 1817 16
TXNPTR
15 14 1312 11 10 9 8
TXNPTR
76543210
TXNPTR
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26.5.8 Transmit Next Counter Register
Name: PERIPH_TNCR
Access: Read-write
• TXNCTR: Transmit Counter Next
TXNCTR contains next transmit buffer size.
When a half duplex peripheral is connected to the PDC, RXNCTR = TXNCTR.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
TXNCTR
76543210
TXNCTR
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26.5.9 Transfer Control Register
Name: PERIPH_PTCR
Access: Write-only
• RXTEN: Receiver Transfer Enable
0: No effect.
1: Enables PDC receiver channel requests if RXTDIS is not set.
When a half duplex peripheral is connected to the PDC, enabling the receiver channel requests automatically disables the
transmitter channel requests. It is forbidden to set both TXTEN and RXTEN for a half duplex peripheral.
• RXTDIS: Receiver Transfer Disable
0: No effect.
1: Disables the PDC receiver channel requests.
When a half duplex peripheral is connected to the PDC, disabling the receiver channel requests also disables the transmit-
ter channel requests.
• TXTEN: Transmitter Transfer Enable
0: No effect.
1: Enables the PDC transmitter channel requests.
When a half duplex peripheral is connected to the PDC, it enables the transmitter channel requests only if RXTEN is not
set. It is forbidden to set both TXTEN and RXTEN for a half duplex peripheral.
• TXTDIS: Transmitter Transfer Disable
0: No effect.
1: Disables the PDC transmitter channel requests.
When a half duplex peripheral is connected to the PDC, disabling the transmitter channel requests disables the receiver
channel requests.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––TXTDISTXTEN
76543210
––––––RXTDISRXTEN
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26.5.10 Transfer Status Register
Name: PERIPH_PTSR
Access: Read-only
• RXTEN: Receiver Transfer Enable
0: PDC Receiver channel requests are disabled.
1: PDC Receiver channel requests are enabled.
• TXTEN: Transmitter Transfer Enable
0: PDC Transmitter channel requests are disabled.
1: PDC Transmitter channel requests are enabled.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––––––TXTEN
76543210
–––––––RXTEN
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27. Clock Generator
27.1 Description
The Clock Generator User Interface is embedded within the Power Management Controller and is described in
Section 28.15 ”Power Management Controller (PMC) User Interface”. However, the Clock Generator registers are
named CKGR_.
27.2 Embedded Characteristics
The Clock Generator is made up of:
A Low Power 32,768 Hz Slow Clock Oscillator with bypass mode.
A Low Power RC Oscillator
A 3 to 20 MHz Crystal or Ceramic Resonator-based Oscillator, which can be bypassed.
A factory programmed Fast RC Oscillator. 3 output frequencies can be selected: 4, 8 or 12 MHz. By default
4MHz is selected.
A 480 MHz UTMI PLL, providing a clock for the USB High Speed Controller.
A 96 to 192 MHz programmable PLL (input from 8 to 16 MHz), capable of providing the clock MCK to the
processor and to the peripherals.
It provides the following clocks:
SLCK, the Slow Clock, which is the only permanent clock within the system.
MAINCK is the output of the Main Clock Oscillator selection: either the Crystal or Ceramic Resonator-based
Oscillator or 4/8/12 MHz Fast RC Oscillator.
PLLACK is the output of the Divider and 96 to 192 MHz programmable PLL (PLLA).
UPLLCK is the output of the 480 MHz UTMI PLL (UPLL).
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27.3 Block Diagram
Figure 27-1. Clock Generator Block Diagram
27.4 Slow Clock
The Supply Controller embeds a slow clock generator that is supplied with the VDDBU power supply. As soon as
the VDDBU is supplied, both the crystal oscillator and the embedded RC oscillator are powered up, but only the
embedded RC oscillator is enabled. This allows the slow clock to be valid in a short time (about 100 µs).
The Slow Clock is generated either by the Slow Clock Crystal Oscillator or by the Slow Clock RC Oscillator.
The selection between the RC or the crystal oscillator is made by writing the XTALSEL bit in the Supply Controller
Control Register (SUPC_CR).
Power
Management
Controller
Main Clock
MAINCK
PLLA Clock
PLLACK
ControlStatus
3-20 MHz
Crystal
Oscillator
MOSCSEL
Clock Generator
PLLA and
Divider
Embedded
12/8/4 MHz
Fast
RC Oscillator
XIN
XOUT
XIN32
XOUT32
Slow Clock
SLCK
XTALSEL
(Supply Controller)
Embedded
32 kHz RC
Oscillator
32768 Hz
Crystal
Oscillator
UPLL Clock
UPLLCK
USB UTMI
PLL
0
1
0
1
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27.4.1 Slow Clock RC Oscillator
By default, the Slow Clock RC Oscillator is enabled and selected. The user has to take into account the possible
drifts of the RC Oscillator. More details are given in the section “DC Characteristics” of the product datasheet.
It can be disabled via the XTALSEL bit in the Supply Controller Control Register (SUPC_CR).
27.4.2 Slow Clock Crystal Oscillator
The Clock Generator integrates a 32,768 Hz low-power oscillator. In order to use this oscillator, the XIN32 and
XOUT32 pins must be connected to a 32,768 Hz crystal. Two external capacitors must be wired as shown in
Figure 27-2. More details are given in the section “DC Characteristics” of the product datasheet.
Note that the user is not obliged to use the Slow Clock Crystal and can use the RC oscillator instead.
Figure 27-2. Typical Slow Clock Crystal Oscillator Connection
The user can select the crystal oscillator to be the source of the slow clock, as it provides a more accurate
frequency. The command is made by writing the Supply Controller Control Register (SUPC_CR) with the
XTALSEL bit at 1. This results in a sequence which enables the crystal oscillator and then disables the RC
oscillator to save power. The switch of the slow clock source is glitch free. The OSCSEL bit of the Supply
Controller Status Register (SUPC_SR) tracks the oscillator frequency downstream. It must be read in order to be
informed when the switch sequence, initiated when a new value is written in MOSCSEL bit of CKGR_MOR, is
done.
Coming back on the RC oscillator is only possible by shutting down the VDDBU power supply. If the user does not
need the crystal oscillator, the XIN32 and XOUT32 pins can be left unconnected.
The user can also set the crystal oscillator in bypass mode instead of connecting a crystal. In this case, the user
has to provide the external clock signal on XIN32. The input characteristics of the XIN32 pin are given in the
product electrical characteristics section. In order to set the bypass mode, the OSCBYPASS bit of the Supply
Controller Mode Register (SUPC_MR) needs to be set at 1.
The user can set the Slow Clock Crystal Oscillator in bypass mode instead of connecting a crystal. In this case, the
user has to provide the external clock signal on XIN32. The input characteristics of the XIN32 pin under these
conditions are given in the product electrical characteristics section.
The programmer has to be sure to set the OSCBYPASS bit in the Supply Controller Mode Register (SUPC_MR)
and XTALSEL bit in the Supply Controller Control Register (SUPC_CR).
XIN32 XOUT32 GND
32,768 Hz
Crystal
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27.5 Main Clock
Figure 27-3 shows the Main Clock block diagram.
Figure 27-3. Main Clock Block Diagram
The Main Clock has two sources:
4/8/12 MHz Fast RC Oscillator which starts very quickly and is used at startup.
3 to 20 MHz Crystal or Ceramic Resonator-based Oscillator which can be bypassed.
27.5.1 4/8/12 MHz Fast RC Oscillator
After reset, the 4/8/12 MHz Fast RC Oscillator is enabled with the 4 MHz frequency selected and it is selected as
the source of MAINCK. MAINCK is the default clock selected to start up the system.
The Fast RC Oscillator 8 and 12 MHz frequencies are calibrated in production. Note that is not the case for the 4
MHz frequency.
Please refer to the “DC Characteristics” section of the product datasheet.
The software can disable or enable the 4/8/12 MHz Fast RC Oscillator with the MOSCRCEN bit in the Clock
Generator Main Oscillator Register (CKGR_MOR).
The user can also select the output frequency of the Fast RC Oscillator, either 4 MHz, 8 MHz or 12 MHz are
available. It can be done through MOSCRCF bits in CKGR_MOR. When changing this frequency selection, the
MOSCRCS bit in the Power Management Controller Status Register (PMC_SR) is automatically cleared and
MAINCK is stopped until the oscillator is stabilized. Once the oscillator is stabilized, MAINCK restarts and
MOSCRCS is set.
XIN
XOUT
MOSCXTEN
MOSCXTCNT
MOSCXTS
Main Clock
Frequency
Counter
MAINF
MAINRDY
SLCK
Slow Clock
3-20 MHz
Crystal
or
Ceramic Resonator
Oscillator
3-20 MHz
Oscillator
Counter
MOSCRCEN
4/8/12 MHz
Fast RC
Oscillator
MOSCRCS
MOSCRCF
MOSCRCEN
MOSCXTEN
MOSCSEL
MOSCSEL MOSCSELS
1
0
MAINCK
Main Clock
MAINCK
Main Clock
Ref.
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When disabling the Main Clock by clearing the MOSCRCEN bit in CKGR_MOR, the MOSCRCS bit in the Power
Management Controller Status Register (PMC_SR) is automatically cleared, indicating the Main Clock is off.
Setting the MOSCRCS bit in the Power Management Controller Interrupt Enable Register (PMC_IER) can trigger
an interrupt to the processor.
It is recommended to disable the Main Clock as soon as the processor no longer uses it and runs out of SLCK,
PLLACKor UPLLCK.
The CAL4, CAL8 and CAL12 values in the PMC Oscillator Calibration Register (PMC_OCR) are the default values
set by Atmel during production. These values are stored in a specific Flash memory area different from the main
memory plane. These values cannot be modified by the user and cannot be erased by a Flash erase command or
by the ERASE pin. Values written by the user's application in PMC_OCR are reset after each power up or
peripheral reset.
27.5.2 3 to 20 MHz Crystal or Ceramic Resonator-based Oscillator
After reset, the 3 to 20 MHz Crystal or Ceramic Resonator-based oscillator is disabled and it is not selected as the
source of MAINCK.
The user can select the 3 to 20 MHz Crystal or Ceramic Resonator-based oscillator to be the source of MAINCK,
as it provides a more accurate frequency. The software enables or disables the main oscillator so as to reduce
power consumption by clearing the MOSCXTEN bit in the Main Oscillator Register (CKGR_MOR).
When disabling the main oscillator by clearing the MOSCXTEN bit in CKGR_MOR, the MOSCXTS bit in PMC_SR
is automatically cleared, indicating the Main Clock is off.
When enabling the main oscillator, the user must initiate the main oscillator counter with a value corresponding to
the startup time of the oscillator. This startup time depends on the crystal frequency connected to the oscillator.
When the MOSCXTEN bit and the MOSCXTCNT are written in CKGR_MOR to enable the main oscillator, the XIN
and XOUT pins are automatically switched into oscillator mode and MOSCXTS bit in the Power Management
Controller Status Register (PMC_SR) is cleared and the counter starts counting down on the slow clock divided by
8 from the MOSCXTCNT value. Since the MOSCXTCNT value is coded with 8 bits, the maximum startup time is
about 62 ms.
When the counter reaches 0, the MOSCXTS bit is set, indicating that the main clock is valid. Setting the
MOSCXTS bit in PMC_IMR can trigger an interrupt to the processor.
27.5.3 Main Clock Oscillator Selection
The user can select either the 4/8/12 MHz Fast RC oscillator or the 3 to 20 MHz Crystal or Ceramic Resonator-
based oscillator to be the source of Main Clock.
The advantage of the 4/8/12 MHz Fast RC oscillator is that it provides fast startup time, this is why it is selected by
default (to start up the system) and when entering Wait Mode.
The advantage of the 3 to 20 MHz Crystal or Ceramic Resonator-based oscillator is that it is very accurate.
The selection is made by writing the MOSCSEL bit in the Main Oscillator Register (CKGR_MOR). The switch of
the Main Clock source is glitch free, so there is no need to run out of SLCK, PLLACKor UPLLCK in order to change
the selection. The MOSCSELS bit of the Power Management Controller Status Register (PMC_SR) allows
knowing when the switch sequence is done.
Setting the MOSCSELS bit in PMC_IMR can trigger an interrupt to the processor.
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27.5.4 Main Clock Frequency Counter
The device features a Main Clock frequency counter that provides the frequency of the Main Clock.
The Main Clock frequency counter is reset and starts incrementing at the Main Clock speed after the next rising
edge of the Slow Clock in the following cases:
when the 4/8/12 MHz Fast RC oscillator clock is selected as the source of Main Clock and when this
oscillator becomes stable (i.e., when the MOSCRCS bit is set)
when the 3 to 20 MHz Crystal or Ceramic Resonator-based oscillator is selected as the source of Main Clock
and when this oscillator becomes stable (i.e., when the MOSCXTS bit is set)
when the Main Clock Oscillator selection is modified
Then, at the 16th falling edge of Slow Clock, the MAINFRDY bit in the Clock Generator Main Clock Frequency
Register (CKGR_MCFR) is set and the counter stops counting. Its value can be read in the MAINF field of
CKGR_MCFR and gives the number of Main Clock cycles during 16 periods of Slow Clock, so that the frequency
of the 4/8/12 MHz Fast RC oscillator or 3 to 20 MHz Crystal or Ceramic Resonator-based oscillator can be
determined.
27.6 Divider and PLL Block
The device features one Divider/PLL Block that permits a wide range of frequencies to be selected on either the
master clock, the processor clock or the programmable clock outputs. Additionally, they provide a 48 MHz signal to
the embedded USB device port regardless of the frequency of the main clock.
Figure 27-4 shows the block diagram of the dividers and PLL blocks.
Figure 27-4. Dividers and PLL Block Diagram
27.6.1 Divider and Phase Lock Loop Programming
The divider can be set between 1 and 255 in steps of 1. When a divider field (DIV) is set to 0, the output of the
corresponding divider and the PLL output is a continuous signal at level 0. On reset, each DIV field is set to 0, thus
the corresponding PLL input clock is set to 0.
The PLL (PLLA) allows multiplication of the divider’s outputs. The PLL clock signal has a frequency that depends
on the respective source signal frequency and on the parameters DIV (DIVA) and MUL (MULA). The factor applied
to the source signal frequency is (MUL + 1)/DIV. When MUL is written to 0, the PLL is disabled and its power
consumption is saved. Re-enabling the PLL can be performed by writing a value higher than 0 in the MUL field.
Whenever the PLL is re-enabled or one of its parameters is changed, the LOCK (LOCKA) bit in PMC_SR is
automatically cleared. The values written in the PLLCOUNT field (PLLACOUNT) in CKGR_PLLR (CKGR_PLLAR)
are loaded in the PLL counter. The PLL counter then decrements at the speed of the Slow Clock until it reaches 0.
Divider
DIVA
PLLA
MULA
PLLACOUNT
LOCKA
OUTA
SLCK
MAINCK PLLACK
PLLA
Counter
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At this time, the LOCK bit is set in PMC_SR and can trigger an interrupt to the processor. The user has to load the
number of Slow Clock cycles required to cover the PLL transient time into the PLLCOUNT field.
The PLL clock can be divided by 2 by writing the PLLDIV2 (PLLADIV2) bit in PMC Master Clock Register
(PMC_MCKR).
It is forbidden to change 4/8/12 MHz Fast RC oscillator, or main selection in CKGR_MOR register while Master
clock source is PLL and PLL reference clock is the Fast RC oscillator.
The user must:
Switch on the Main RC oscillator by writing 1 in CSS field of PMC_MCKR.
Change the frequency (MOSCRCF) or oscillator selection (MOSCSEL) in CKGR_MOR.
Wait for MOSCRCS (if frequency changes) or MOSCSELS (if oscillator selection changes) in PMC_IER.
Disable and then enable the PLL (LOCK in PMC_IDR and PMC_IER).
Wait for PLLRDY.
Switch back to PLL.
27.7 UTMI Phase Lock Loop Programming
The source clock of the UTMI PLL is the 3-20 MHz crystal oscillator. A 12 MHz crystal is needed to use the USB.
Figure 27-5. UTMI PLL Block Diagram
Whenever the UTMI PLL is enabled by writing UPLLEN in CKGR_UCKR, the LOCKU bit in PMC_SR is
automatically cleared. The values written in the PLLCOUNT field in CKGR_UCKR are loaded in the UTMI PLL
counter. The UTMI PLL counter then decrements at the speed of the Slow Clock divided by 8 until it reaches 0. At
this time, the LOCKU bit is set in PMC_SR and can trigger an interrupt to the processor. The user has to load the
number of Slow Clock cycles required to cover the UTMI PLL transient time into the PLLCOUNT field.
UTMI PLL
UPLLEN
UPLLCOUNT
LOCKU
SLCK
MAINCK UPLLCK
UTMI PLL
Counter
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28. Power Management Controller (PMC)
28.1 Description
The Power Management Controller (PMC) optimizes power consumption by controlling all system and user
peripheral clocks. The PMC enables/disables the clock inputs to many of the peripherals and the Cortex-M3
Processor.
The Supply Controller selects between the 32 kHz RC oscillator or the crystal oscillator. The unused oscillator is
disabled automatically so that power consumption is optimized.
By default, at startup the chip runs out of the Master Clock using the Fast RC oscillator running at 4 MHz.
The user can trim the 8 and 12 MHz RC Oscillator frequencies by software.
28.2 Embedded Characteristics
The Power Management Controller provides the following clocks:
MCK, the Master Clock, programmable from a few hundred Hz to the maximum operating frequency of the
device. It is available to the modules running permanently, such as the Enhanced Embedded Flash
Controller.
Processor Clock (HCLK) is automatically switched off when the processor enters Sleep Mode.
Free running processor Clock (FCLK)
the Cortex-M3 SysTick external clock
UDP Clock (UDPCK), required by USB Device Port operations.
Peripheral Clocks, typically MCK, provided to the embedded peripherals (USART, SSC, SPI, TWI, TC,
HSMCI, etc.) and independently controllable. Some of the peripherals can be configured to be driven by
MCK divided by 2, 4.In order to reduce the number of clock names in a product, the Peripheral Clocks are
named MCK in the product datasheet.
Programmable Clock Outputs can be selected from the clocks provided by the clock generator and driven on the
PCKx pins.
The Power Management Controller also provides the following operations on clocks:
a main crystal oscillator clock failure detector.
a frequency counter on main clock .
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28.3 Block Diagram
Figure 28-1. General Clock Block Diagram
Figure 28-2. Peripheral Clock Divider Block Diagram
Power
Management
Controller
Main Clock
MAINCK
PLLA Clock
PLLACK
ControlStatus
3-20 MHz
Crystal
or
Ceramic
Resonator
Oscillator
MOSCSEL
Clock Generator
PLLA and
Divider /2
XIN
XOUT
XIN32
XOUT32
Slow Clock
SLCK
XTALSEL
(Supply Controller)
Embedded
32 kHz RC
Oscillator
32768 Hz
Crystal
Oscillator
UPLL Clock
UPLLCK
0
1
0
1
MCK
periph_clk[..]
int
SLCK
MAINCK
PLLACK
Prescaler
/1,/2,/3,/4,/8,
/16,/32,/64
HCLK
Processor
Clock
Controller
Sleep Mode
Master Clock Controller
(PMC_MCKR)
Peripherals
Clock Controller
(PMC_PCERx) ON/OFF
USB FS Clock
Prescaler
/1,/2,/4,/8,
/16,/32,/64 pck[..]
ON/OFF
FCLK
SysTick
Divider
/8
SLCK
MAINCK
PLLACK
UPLLCK/2
Processor clock
Free running clock
Master clock
USB UTMI
PLL
Embedded
4/8/12 MHz
Fast
RC Oscillator
Programmable Clock Controller
(PMC_PCKx)
PRES
PLLADIV2 PRESCSS
CSS
Divider
/1, /2
USB_48M
UPLLDIV
Divider
/1,/2,/3,...,/16
USB Clock Controller (PMC_USB)
USBDIVUSBS
ON/OFF
UPLLCK/2
USB_480M
USB HS Clock
PLLACK
UPLLCK/2
MCK
MCK
periph_clk[n]
int
SLCK
MAINCK
PLLACK
Prescaler
/1,/2,/3,/4,/8,
/16,/32,/64
HCLK
Processor
Clock
Controller
Sleep Mode
Master Clock Controller
(PMC_MCKR)
Peripherals
Clock Controller
(PMC_PCERx)
PLLBCK
Processor clockc
Master clock
PRESCSS ON/OFF
ON/OFF
ON/OFF
periph_clk[n+1]
periph_clk[n+2]
Peripherals
Control Register
(PMC_PCR)
DIV(PID = n+1)
DIV(PID = n+2)
Divider
/2, /4
MCK
MCK
div4
div2
div4
div2
div4
div2
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28.4 Master Clock Controller
The Master Clock Controller provides selection and division of the Master Clock (MCK). MCK is the clock provided
to all the peripherals.
The Master Clock is selected from one of the clocks provided by the Clock Generator. Selecting the Slow Clock
provides a Slow Clock signal to the whole device. Selecting the Main Clock saves power consumption of the PLLs.
The Master Clock Controller is made up of a clock selector and a prescaler.
The Master Clock selection is made by writing the CSS field (Clock Source Selection) in PMC_MCKR (Master
Clock Register). The prescaler supports the division by a power of 2 of the selected clock between 1 and 64, and
the division by 3. The PRES field in PMC_MCKR programs the prescaler.
Each time PMC_MCKR is written to define a new Master Clock, the MCKRDY bit is cleared in PMC_SR. It reads 0
until the Master Clock is established. Then, the MCKRDY bit is set and can trigger an interrupt to the processor.
This feature is useful when switching from a high-speed clock to a lower one to inform the software when the
change is actually done.
Figure 28-3. Master Clock Controller
28.5 Processor Clock Controller
The PMC features a Processor Clock Controller (HCLK) that implements the Processor Sleep Mode. The
Processor Clock can be disabled by executing the WFI (WaitForInterrupt) or the WFE (WaitForEvent) processor
instruction while the LPM bit is at 0 in the PMC Fast Startup Mode Register (PMC_FSMR).
The Processor Clock HCLK is enabled after a reset and is automatically re-enabled by any enabled interrupt. The
Processor Sleep Mode is achieved by disabling the Processor Clock, which is automatically re-enabled by any
enabled fast or normal interrupt, or by the reset of the product.
When Processor Sleep Mode is entered, the current instruction is finished before the clock is stopped, but this
does not prevent data transfers from other masters of the system bus.
28.6 SysTick Clock
The SysTick calibration value is fixed to 10500 which allows the generation of a time base of 1 ms with SysTick
clock to the maximum frequency on MCK divided by 8.
28.7 Peripheral Clock Controller
The Power Management Controller controls the clocks of each embedded peripheral by means of the Peripheral
Clock Controller. The user can individually enable and disable the Clock on the peripherals.
The user can also enable and disable these clocks by writing Peripheral Clock Enable 0 (PMC_PCER0),
Peripheral Clock Disable 0 (PMC_PCDR0), Peripheral Clock Enable 1 (PMC_PCER1) and Peripheral Clock
SLCK
Master Clock
Prescaler MCK
PRESCSS
MAINCK
PLLACK
UPLLCK/2
To the Processor
Clock Controller (PCK)
PMC_MCKR PMC_MCKR
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Disable 1 (PMC_PCDR1) registers. The status of the peripheral clock activity can be read in the Peripheral Clock
Status Register (PMC_PCSR0) and Peripheral Clock Status Register (PMC_PCSR1).
When a peripheral clock is disabled, the clock is immediately stopped. The peripheral clocks are automatically
disabled after a reset.
In order to stop a peripheral, it is recommended that the system software wait until the peripheral has executed its
last programmed operation before disabling the clock. This is to avoid data corruption or erroneous behavior of the
system.
The bit number within the Peripheral Clock Control registers (PMC_PCER0-1, PMC_PCDR0-1, and
PMC_PCSR0-1) is the Peripheral Identifier defined at the product level. The bit number corresponds to the
interrupt source number assigned to the peripheral.
In order to save power consumption, the clock of CAN0, CAN1 peripherals can be MCK divided by a division factor
of 1, 2, 4.
This is done by setting the PMC_PCR register. It features a command and acts like a mailbox. To write the division
factor, the user needs to write a WRITE command, the peripheral ID and the chosen division factor. To read the
current division factor, the user just needs to write the READ command and the peripheral ID. Then a read access
on PMC_PCR must be performed.
DIV must not be changed while peripheral is in use or when the peripheral clock is enabled.To change the clock
division factor (DIV) of a peripheral, its clock must first be disabled by writing either EN to 0 for the corresponding
PID (DIV must be kept the same if this method is used), or writing to PMC_PCDR register. Then a second write
must be performed into PMC_PCR with the new value of DIV and a third write must be performed to enable the
peripheral clock (either by using PMC_PCR or PMC_PCER register).
Code Example to select divider 4 for peripheral index 43 (0x2B) and enable its clock:
write_register(PMC_PCR,0x1002102B)
Code Example to read the divider of the same peripheral:
write_register(PMC_PCR,0x0000002B)
read_register(PMC_PCR)
28.8 Free Running Processor Clock
The Free Running Processor Clock (FCLK) used for sampling interrupts and clocking debug blocks ensures that
interrupts can be sampled, and sleep events can be traced, while the processor is sleeping. It is connected to
Master Clock (MCK).
28.9 Programmable Clock Output Controller
The PMC controls 3 signals to be output on external pins, PCKx. Each signal can be independently programmed
via the Programmable Clock Registers (PMC_PCKx).
PCKx can be independently selected between the Slow Clock (SLCK), the Main Clock (MAINCK), the PLLA Clock
(PLLACK), UTMI PLL Clock (UPLLCK/2) and the Master Clock (MCK) by writing the CSS field in PMC_PCKx.
Each output signal can also be divided by a power of 2 between 1 and 64 by writing the PRES (Prescaler) field in
PMC_PCKx.
Each output signal can be enabled and disabled by writing 1 in the corresponding bit, PCKx of PMC_SCER and
PMC_SCDR, respectively. Status of the active programmable output clocks are given in the PCKx bits of
PMC_SCSR (System Clock Status Register).
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Moreover, like the PCK, a status bit in PMC_SR indicates that the Programmable Clock is actually what has been
programmed in the Programmable Clock registers.
As the Programmable Clock Controller does not manage with glitch prevention when switching clocks, it is strongly
recommended to disable the Programmable Clock before any configuration change and to re-enable it after the
change is actually performed.
28.10 Fast Startup
The device allows the processor to restart in less than 10 microseconds while the device is in Wait mode. The
system enters Wait mode by executing the WaitForEvent (WFE) instruction of the processor while the LPM bit is
at 1 in the PMC Fast Startup Mode Register (PMC_FSMR).
Important: Prior to asserting any WFE instruction to the processor, the internal sources of wakeup provided by
RTT, RTC and USB must be cleared and verified too, that none of the enabled external wakeup inputs (WKUP)
hold an active polarity.
A Fast Startup is enabled upon the detection of a programmed level on one of the 16 wake-up inputs (WKUP) or
upon an active alarm from the RTC, RTT and USB Controller. The polarity of the 16 wake-up inputs is
programmable by writing the PMC Fast Startup Polarity Register (PMC_FSPR).
The Fast Restart circuitry, as shown in Figure 28-4, is fully asynchronous and provides a fast startup signal to the
Power Management Controller. As soon as the fast startup signal is asserted, the embedded 4/8/12 MHz Fast RC
oscillator restarts automatically.
Figure 28-4. Fast Startup Circuitry
Each wake-up input pin and alarm can be enabled to generate a Fast Startup event by writing 1 to the
corresponding bit in the Fast Startup Mode Register PMC_FSMR.
fast_restart
WKUP15
FSTT15
FSTP15
WKUP1
FSTT1
FSTP1
WKUP0
FSTT0
FSTP0
RTTAL
RTCAL
USBAL
RTT Alarm
RTC Alarm
USB Alarm
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The user interface does not provide any status for Fast Startup, but the user can easily recover this information by
reading the PIO Controller, and the status registers of the RTC, RTT and USB Controller.
28.11 Main Crystal Clock Failure Detector
The clock failure detector monitors the 3 to 20 MHz Crystal or Ceramic Resonator-based oscillator to identify an
eventual defect of this oscillator (for example, if the crystal is unconnected).
The clock failure detector can be enabled or disabled by means of the CFDEN bit in the PMC Clock Generator
Main Oscillator Register (CKGR_MOR). After reset, the detector is disabled. However, if the 3 to 20 MHz Crystal or
Ceramic Resonator-based Oscillator is disabled, the clock failure detector is disabled too.
A failure is detected by means of a counter incrementing on the 3 to 20 MHz Crystal oscillator or Ceramic
Resonator-based oscillator clock edge and timing logic clocked on the slow clock RC oscillator controlling the
counter. The counter is cleared when the slow clock RC oscillator signal is low and enabled when the slow clock
RC oscillator is high. Thus the failure detection time is 1 slow clock RC oscillator clock period. If, during the high
level period of the slow clock RC oscillator, less than 8 fast crystal oscillator clock periods have been counted, then
a failure is declared.
If a failure of the 3 to 20 MHz Crystal or Ceramic Resonator-based oscillator clock is detected, the CFDEV flag is
set in the PMC Status Register (PMC_SR), and generates an interrupt if it is not masked. The interrupt remains
active until a read operation in the PMC_SR register. The user can know the status of the clock failure detector at
any time by reading the CFDS bit in the PMC_SR register.
If the 3 to 20 MHz Crystal or Ceramic Resonator-based oscillator clock is selected as the source clock of MAINCK
(MOSCSEL = 1), and if the Master Clock Source is PLLACK or UPLLCK (CSS = 2 or 3), a clock failure detection
automatically forces MAINCK to be the source clock for the master clock (MCK).Then, regardless of the PMC
configuration, a clock failure detection automatically forces the 4/8/12 MHz Fast RC oscillator to be the source
clock for MAINCK. If the Fast RC oscillator is disabled when a clock failure detection occurs, it is automatically re-
enabled by the clock failure detection mechanism.
It takes 2 slow clock RC oscillator cycles to detect and switch from the 3 to 20 MHz Crystal, or Ceramic Resonator-
based oscillator, to the 4/8/12 MHz Fast RC Oscillator if the Master Clock source is Main Clock, or 3 slow clock RC
oscillator cycles if the Master Clock source is PLLACK or UPLLCK.
A clock failure detection activates a fault output that is connected to the Pulse Width Modulator (PWM) Controller.
With this connection, the PWM controller is able to force its outputs and to protect the driven device, if a clock
failure is detected. This fault output remains active until the defect is detected and until it is cleared by the bit
FOCLR in the PMC Fault Output Clear Register (PMC_FOCR).
The user can know the status of the fault output at any time by reading the FOS bit in the PMC_SR register.
28.12 Programming Sequence
1. Enabling the Main Oscillator:
The main oscillator is enabled by setting the MOSCXTEN field in the Main Oscillator Register
(CKGR_MOR). The user can define a start-up time. This can be achieved by writing a value in the
MOSCXTST field in CKGR_MOR. Once this register has been correctly configured, the user must wait for
MOSCXTS field in the PMC_SR register to be set. This can be done either by polling the status register, or
by waiting the interrupt line to be raised if the associated interrupt to MOSCXTS has been enabled in the
PMC_IER register.
Start Up Time = 8 * MOSCXTST / SLCK = 56 Slow Clock Cycles.
The main oscillator will be enabled (MOSCXTS bit set) after 56 Slow Clock Cycles.
2. Checking the Main Oscillator Frequency (Optional):
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In some situations the user may need an accurate measure of the main clock frequency. This measure can
be accomplished via the Main Clock Frequency Register (CKGR_MCFR).
Once the MAINFRDY field is set in CKGR_MCFR, the user may read the MAINF field in CKGR_MCFR. This
provides the number of main clock cycles within sixteen slow clock cycles.
3. Setting PLL and Divider:
All parameters needed to configure PLLA and the divider are located in CKGR_PLLAR.
The DIV field is used to control the divider itself. It must be set to 1 when PLL is used. By default, DIV
parameter is set to 0 which means that the divider is turned off.
The MUL field is the PLL multiplier factor. This parameter can be programmed between 0 and 2047. If MUL
is set to 0, PLL will be turned off, otherwise the PLL output frequency is PLL input frequency multiplied by
(MUL + 1).
The PLLCOUNT field specifies the number of slow clock cycles before the LOCK bit is set in PMC_SR, after
CKGR_PLLAR has been written.
Once the CKGR_PLL register has been written, the user must wait for the LOCK bit to be set in the
PMC_SR. This can be done either by polling the status register or by waiting the interrupt line to be raised if
the associated interrupt to LOCK has been enabled in PMC_IER. All parameters in CKGR_PLLAR can be
programmed in a single write operation. If at some stage one of the following parameters, MUL or DIV is
modified, the LOCK bit will go low to indicate that PLL is not ready yet. When PLL is locked, LOCK will be set
again. The user is constrained to wait for LOCK bit to be set before using the PLL output clock.
4. Selection of Master Clock and Processor Clock
The Master Clock and the Processor Clock are configurable via the Master Clock Register (PMC_MCKR).
The CSS field is used to select the Master Clock divider source. By default, the selected clock source is
main clock.
The PRES field is used to control the Master Clock prescaler. The user can choose between different values
(1, 2, 3, 4, 8, 16, 32, 64). Master Clock output is prescaler input divided by PRES parameter. By default,
PRES parameter is set to 1 which means that master clock is equal to main clock.
Once PMC_MCKR has been written, the user must wait for the MCKRDY bit to be set in PMC_SR. This can
be done either by polling the status register or by waiting for the interrupt line to be raised if the associated
interrupt to MCKRDY has been enabled in the PMC_IER register.
The PMC_MCKR must not be programmed in a single write operation. The preferred programming
sequence for PMC_MCKR is as follows:
If a new value for CSS field corresponds to PLL Clock,
̶Program the PRES field in PMC_MCKR.
̶Wait for the MCKRDY bit to be set in PMC_SR.
̶Program the CSS field in PMC_MCKR.
̶Wait for the MCKRDY bit to be set in PMC_SR.
If a new value for CSS field corresponds to Main Clock or Slow Clock,
̶Program the CSS field in PMC_MCKR.
̶Wait for the MCKRDY bit to be set in the PMC_SR.
̶Program the PRES field in PMC_MCKR.
̶Wait for the MCKRDY bit to be set in PMC_SR.
If at some stage one of the following parameters, CSS or PRES is modified, the MCKRDY bit will go low to
indicate that the Master Clock and the Processor Clock are not ready yet. The user must wait for MCKRDY
bit to be set again before using the Master and Processor Clocks.
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Note: IF PLLx clock was selected as the Master Clock and the user decides to modify it by writing in CKGR_PLLR, the
MCKRDY flag will go low while PLL is unlocked. Once PLL is locked again, LOCK goes high and MCKRDY is set.
While PLL is unlocked, the Master Clock selection is automatically changed to Slow Clock. For further information, see
Section 28.13.0.2 “Clock Switching Waveforms” on page 535.
Code Example:
write_register(PMC_MCKR,0x00000001)
wait (MCKRDY=1)
write_register(PMC_MCKR,0x00000011)
wait (MCKRDY=1)
The Master Clock is main clock divided by 2.
The Processor Clock is the Master Clock.
5. Selection of Programmable Clocks
Programmable clocks are controlled via registers, PMC_SCER, PMC_SCDR and PMC_SCSR.
Programmable clocks can be enabled and/or disabled via PMC_SCER and PMC_SCDR. 3 Programmable
clocks can be enabled or disabled. The PMC_SCSR provides a clear indication as to which Programmable
clock is enabled. By default all Programmable clocks are disabled.
Programmable Clock Registers (PMC_PCKx) are used to configure Programmable clocks.
The CSS field is used to select the Programmable clock divider source. Four clock options are available:
main clock, slow clock, PLLACK, UPLLCK. By default, the clock source selected is slow clock.
The PRES field is used to control the Programmable clock prescaler. It is possible to choose between
different values (1, 2, 4, 8, 16, 32, 64). Programmable clock output is prescaler input divided by PRES
parameter. By default, the PRES parameter is set to 0 which means that master clock is equal to slow clock.
Once PMC_PCKx has been programmed, The corresponding Programmable clock must be enabled and the
user is constrained to wait for the PCKRDYx bit to be set in PMC_SR. This can be done either by polling the
status register or by waiting the interrupt line to be raised, if the associated interrupt to PCKRDYx has been
enabled in the PMC_IER register. All parameters in PMC_PCKx can be programmed in a single write
operation.
If the CSS and PRES parameters are to be modified, the corresponding Programmable clock must be
disabled first. The parameters can then be modified. Once this has been done, the user must re-enable the
Programmable clock and wait for the PCKRDYx bit to be set.
6. Enabling Peripheral Clocks
Once all of the previous steps have been completed, the peripheral clocks can be enabled and/or disabled
via registers PMC_PCER0, PMC_PCER, PMC_PCDR0 and PMC_PCDR.
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28.13 Clock Switching Details
28.13.0.1Master Clock Switching Timings
Table 28-1 and Table 28-2 give the worst case timings required for the Master Clock to switch from one selected
clock to another one. This is in the event that the prescaler is de-activated. When the prescaler is activated, an
additional time of 64 clock cycles of the newly selected clock has to be added.
Notes: 1. PLL designates either the PLLA or the UPLL clock.
2. PLLCOUNT designates either PLLACOUNT or UPLLCOUNT.
Table 28-1. Clock Switching Timings (Worst Case)
From Main Clock SLCK PLL Clock
To
Main Clock – 4 x SLCK +
2.5 x Main Clock
3 x PLL Clock +
4 x SLCK +
1 x Main Clock
SLCK 0.5 x Main Clock +
4.5 x SLCK –3 x PLL Clock +
5 x SLCK
PLL Clock
0.5 x Main Clock +
4 x SLCK +
PLLCOUNT x SLCK +
2.5 x PLLx Clock
2.5 x PLL Clock +
5 x SLCK +
PLLCOUNT x SLCK
2.5 x PLL Clock +
4 x SLCK +
PLLCOUNT x SLCK
Table 28-2. Clock Switching Timings between Two PLLs (Worst Case)
From PLLA Clock UPLL Clock
To
PLLA Clock 2.5 x PLLA Clock +
4 x SLCK +
PLLACOUNT x SLCK
3 x PLLA Clock +
4 x SLCK +
1.5 x PLLA Clock
UPLL Clock 3 x UPLL Clock +
4 x SLCK +
1.5 x UPLL Clock
2.5 x UPLL Clock +
4 x SLCK +
x SLCK
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28.13.0.2Clock Switching Waveforms
Figure 28-5. Switch Master Clock from Slow Clock to PLLx Clock
Figure 28-6. Switch Master Clock from Main Clock to Slow Clock
Slow Clock
LOCK
MCKRDY
Master Clock
Write PMC_MCKR
PLLx Clock
Slow Clock
Main Clock
MCKRDY
Master Clock
Write PMC_MCKR
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Figure 28-7. Change PLLx Programming
Figure 28-8. Programmable Clock Output Programming
Slow Clock
Slow Clock
PLLx Clock
LOCKx
MCKRDY
Master Clock
Write CKGR_PLLxR
PLLx Clock
PCKRDY
PCKx Output
Write PMC_PCKx
Write PMC_SCER
Write PMC_SCDR PCKx is disabled
PCKx is enabled
PLL Clock is selected
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28.14 Write Protection Registers
To prevent any single software error that may corrupt PMC behavior, certain address spaces can be write
protected by setting the WPEN bit in the “PMC Write Protect Mode Register” (PMC_WPMR).
If a write access to the protected registers is detected, then the WPVS flag in the PMC Write Protect Status
Register (PMC_WPSR) is set and the field WPVSRC indicates in which register the write access has been
attempted.
The WPVS flag is reset by writing the PMC Write Protect Mode Register (PMC_WPMR) with the appropriate
access key, WPKEY.
The protected registers are:
“PMC System Clock Enable Register”
“PMC System Clock Disable Register”
“PMC Peripheral Clock Enable Register 0”
“PMC Peripheral Clock Disable Register 0”
“PMC Clock Generator Main Oscillator Register”
“PMC Clock Generator PLLA Register”
“PMC UTMI Clock Configuration Register”
“PMC Master Clock Register”
“PMC USB Clock Register”
“PMC Programmable Clock Register”
“PMC Fast Startup Mode Register”
“PMC Fast Startup Polarity Register”
“PMC Peripheral Clock Enable Register 1”
“PMC Peripheral Clock Disable Register 1”
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28.15 Power Management Controller (PMC) User Interface
Note: If an offset is not listed in the table it must be considered as “reserved”.
Table 28-3. Register Mapping
Offset Register Name Access Reset
0x0000 System Clock Enable Register PMC_SCER Write-only –
0x0004 System Clock Disable Register PMC_SCDR Write-only –
0x0008 System Clock Status Register PMC_SCSR Read-only 0x0000_0001
0x000C Reserved – – –
0x0010 Peripheral Clock Enable Register 0 PMC_PCER0 Write-only –
0x0014 Peripheral Clock Disable Register 0 PMC_PCDR0 Write-only –
0x0018 Peripheral Clock Status Register 0 PMC_PCSR0 Read-only 0x0000_0000
0x001C UTMI Clock Register CKGR_UCKR Read-write 0x1020_0800
0x0020 Main Oscillator Register CKGR_MOR Read-write 0x0000_0001
0x0024 Main Clock Frequency Register CKGR_MCFR Read-only 0x0000_0000
0x0028 PLLA Register CKGR_PLLAR Read-write 0x0000_3F00
0x002C Reserved – – –
0x0030 Master Clock Register PMC_MCKR Read-write 0x0000_0001
0x0034 Reserved – – –
0x0038 USB Clock Register PMC_USB Read/Write 0x0000_0000
0x003C Reserved – – –
0x0040 Programmable Clock 0 Register PMC_PCK0 Read-write 0x0000_0000
0x0044 Programmable Clock 1 Register PMC_PCK1 Read-write 0x0000_0000
0x0048 Programmable Clock 2 Register PMC_PCK2 Read-write 0x0000_0000
0x004C - 0x005C Reserved – – –
0x0060 Interrupt Enable Register PMC_IER Write-only –
0x0064 Interrupt Disable Register PMC_IDR Write-only –
0x0068 Status Register PMC_SR Read-only 0x0001_0008
0x006C Interrupt Mask Register PMC_IMR Read-only 0x0000_0000
0x0070 Fast Startup Mode Register PMC_FSMR Read-write 0x0000_0000
0x0074 Fast Startup Polarity Register PMC_FSPR Read-write 0x0000_0000
0x0078 Fault Output Clear Register PMC_FOCR Write-only –
0x007C- 0x00E0 Reserved – – –
0x00E4 Write Protect Mode Register PMC_WPMR Read-write 0x0
0x00E8 Write Protect Status Register PMC_WPSR Read-only 0x0
0x00EC-0x00FC Reserved – – –
0x0100 Peripheral Clock Enable Register 1 PMC_PCER1 Write-only –
0x0104 Peripheral Clock Disable Register 1 PMC_PCDR1 Write-only –
0x0108 Peripheral Clock Status Register 1 PMC_PCSR1 Read-only 0x0000_0000
0x010C Peripheral Control Register PMC_PCR Read-write 0x0000_0000
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28.15.1 PMC System Clock Enable Register
Name: PMC_SCER
Address: 0x400E0600
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• UOTGCLK: Enable USB OTG Clock (48 MHz, USB_48M) for UTMI
Enable only when UOTGHS module is in low-power mode (SPDCONF =1).
0 = No effect.
1 = Enable USB_48M (to use if SPDCONF =1).
• PCKx: Programmable Clock x Output Enable
0 = No effect.
1 = Enables the corresponding Programmable Clock output.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––––PCK2PCK1PCK0
76543210
––UOTGCLK–––––
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28.15.2 PMC System Clock Disable Register
Name: PMC_SCDR
Address: 0x400E0604
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• UOTGCLK: Disable USB OTG Clock (48 MHz, USB_48M) for UTMI
Enable only when UOTGHS module is in low-power mode (SPDCONF =1).
0: No effect.
1: Disable USB_48M (to use if SPDCONF =1).
• PCKx: Programmable Clock x Output Disable
0 = No effect.
1 = Disables the corresponding Programmable Clock output.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––––PCK2PCK1PCK0
76543210
––UOTGCLK–––––
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28.15.3 PMC System Clock Status Register
Name: PMC_SCSR
Address: 0x400E0608
Access: Read-only
• UOTGCLK: USB OTG Clock (48 MHz, USB_48M) Clock Status
0 = The 48 MHz clock (UOTGCK) of the USB OTG FS Port is disabled.
1 = The 48 MHz clock (UOTGCK) of the USB OTG FS Port is enabled.
• PCKx: Programmable Clock x Output Status
0 = The corresponding Programmable Clock output is disabled.
1 = The corresponding Programmable Clock output is enabled.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––––PCK2PCK1PCK0
76543210
––UOTGCLK–––––
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28.15.4 PMC Peripheral Clock Enable Register 0
Name: PMC_PCER0
Address: 0x400E0610
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• PIDx: Peripheral Clock x Enable
0 = No effect.
1 = Enables the corresponding peripheral clock.
Note: To get PIDx, refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet. Other peripherals can be
enabled in PMC_PCER1 (Section 28.15.23 ”PMC Peripheral Clock Enable Register 1”).
Note: Programming the control bits of the Peripheral ID that are not implemented has no effect on the behavior of the PMC.
3130292827 26 25 24
PID31PID30PID29PID28PID27 PID26 PID25 PID24
2322 21 20 19 1817 16
PID23PID22 PID21 PID20 PID19 PID18PID17 PID16
15 14 1312 11 10 9 8
PID15 PID14 PID13PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3PID2 – –
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28.15.5 PMC Peripheral Clock Disable Register 0
Name: PMC_PCDR0
Address: 0x400E0614
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• PIDx: Peripheral Clock x Disable
0 = No effect.
1 = Disables the corresponding peripheral clock.
Note: To get PIDx, refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet. Other peripherals can be
disabled in PMC_PCDR1 (Section 28.15.24 ”PMC Peripheral Clock Disable Register 1”).
3130292827 26 25 24
PID31PID30PID29PID28PID27 PID26 PID25 PID24
2322 21 20 19 1817 16
PID23PID22 PID21 PID20 PID19 PID18PID17 PID16
15 14 1312 11 10 9 8
PID15 PID14 PID13PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3PID2 - -
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28.15.6 PMC Peripheral Clock Status Register 0
Name: PMC_PCSR0
Address: 0x400E0618
Access: Read-only
• PIDx: Peripheral Clock x Status
0 = The corresponding peripheral clock is disabled.
1 = The corresponding peripheral clock is enabled.
Note: To get PIDx, refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet. Other peripherals status
can be read in PMC_PCSR1 (Section 28.15.25 ”PMC Peripheral Clock Status Register 1”).
3130292827 26 25 24
PID31PID30PID29PID28PID27 PID26 PID25 PID24
2322 21 20 19 1817 16
PID23PID22 PID21 PID20 PID19 PID18PID17 PID16
15 14 1312 11 10 9 8
PID15 PID14 PID13PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3PID2 – –
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28.15.7 PMC UTMI Clock Configuration Register
Name: CKGR_UCKR
Address: 0x400E061C
Access: Read-write
This register can only be written if the WPEN bit is cleared in the “PMC Write Protect Mode Register” .
• UPLLEN: UTMI PLL Enable
0: The UTMI PLL is disabled.
1: The UTMI PLL is enabled.
When UPLLEN is set, the LOCKU flag is set once the UTMI PLL startup time is achieved.
• UPLLCOUNT: UTMI PLL Start-up Time
Specifies the number of Slow Clock cycles multiplied by 8 for the UTMI PLL start-up time.
31 30 29 28 27 26 25 24
––– ––––
23 22 21 20 19 18 17 16
UPLLCOUNT – – – UPLLEN
15 14 13 12 11 10 9 8
––––––––
76543210
––––––––
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28.15.8 PMC Clock Generator Main Oscillator Register
Name: CKGR_MOR
Address: 0x400E0620
Access: Read-write
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• KEY: Password
Should be written at value 0x37. Writing any other value in this field aborts the write operation.
• MOSCXTEN: Main Crystal Oscillator Enable
A crystal must be connected between XIN and XOUT.
0 = The Main Crystal Oscillator is disabled.
1 = The Main Crystal Oscillator is enabled. MOSCXTBY must be set to 0.
When MOSCXTEN is set, the MOSCXTS flag is set once the Main Crystal Oscillator startup time is achieved.
• MOSCXTBY: Main Crystal Oscillator Bypass
0 = No effect.
1 = The Main Crystal Oscillator is bypassed. MOSCXTEN must be set to 0. An external clock must be connected on XIN.
When MOSCXTBY is set, the MOSCXTS flag in PMC_SR is automatically set.
Clearing MOSCXTEN and MOSCXTBY bits allows resetting the MOSCXTS flag.
• MOSCRCEN: Main On-Chip RC Oscillator Enable
0 = The Main On-Chip RC Oscillator is disabled.
1 = The Main On-Chip RC Oscillator is enabled.
When MOSCRCEN is set, the MOSCRCS flag is set once the Main On-Chip RC Oscillator startup time is achieved.
• MOSCRCF: Main On-Chip RC Oscillator Frequency Selection
At start-up, the Main On-Chip RC Oscillator frequency is 4 MHz.
31 30 29 28 27 26 25 24
––––––CFDENMOSCSEL
23 22 21 20 19 18 17 16
KEY
15 14 13 12 11 10 9 8
MOSCXTST
76543210
– MOSCRCF MOSCRCEN – MOSCXTBY MOSCXTEN
Value Name Description
0x0 4_MHz The Fast RC Oscillator Frequency is at 4 MHz (default)
0x1 8_MHz The Fast RC Oscillator Frequency is at 8 MHz
0x2 12_MHz The Fast RC Oscillator Frequency is at 12 MHz
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• MOSCXTST: Main Crystal Oscillator Start-up Time
Specifies the number of Slow Clock cycles multiplied by 8 for the Main Crystal Oscillator start-up time.
• MOSCSEL: Main Oscillator Selection
0 = The Main On-Chip RC Oscillator is selected.
1 = The Main Crystal Oscillator is selected.
• CFDEN: Clock Failure Detector Enable
0 = The Clock Failure Detector is disabled.
1 = The Clock Failure Detector is enabled.
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28.15.9 PMC Clock Generator Main Clock Frequency Register
Name: CKGR_MCFR
Address: 0x400E0624
Access: Read-only
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• MAINF: Main Clock Frequency
Gives the number of Main Clock cycles within 16 Slow Clock periods.
• MAINFRDY: Main Clock Ready
0 = MAINF value is not valid or the Main Oscillator is disabled .
1 = The Main Oscillator has been enabled previously and MAINF value is available.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––––MAINFRDY
15 14 13 12 11 10 9 8
MAINF
76543210
MAINF
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28.15.10 PMC Clock Generator PLLA Register
Name: CKGR_PLLAR
Address: 0x400E0628
Access: Read-write
Possible limitations on PLLA input frequencies and multiplier factors should be checked before using the PMC.
Warning: Bit 29 must always be set to 1 when programming the CKGR_PLLAR register.
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• DIVA: Divider
• PLLACOUNT: PLLA Counter
Specifies the number of Slow Clock cycles x8 before the LOCKA bit is set in PMC_SR after CKGR_PLLAR is written.
• MULA: PLLA Multiplier
0 = The PLLA is deactivated.
1 up to 2047 = The PLLA Clock frequency is the PLLA input frequency multiplied by MULA + 1.
• ONE: Must Be Set to 1
Bit 29 must always be set to 1 when programming the CKGR_PLLAR register.
31 30 29 28 27 26 25 24
––ONE–– MULA
23 22 21 20 19 18 17 16
MULA
15 14 13 12 11 10 9 8
– – PLLACOUNT
76543210
DIVA
DIVA Divider Selected
0 Divider output is 0
1 Divider is bypassed (DIVA=1)
2 - 255 Divider output is DIVA
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28.15.11 PMC Master Clock Register
Name: PMC_MCKR
Address: 0x400E0630
Access: Read-write
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• CSS: Master Clock Source Selection
• PRES: Processor Clock Prescaler
• PLLADIV2: PLLA Divisor by 2
• UPLLDIV2:UPLLDivisor by 2
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––UPLLDIV2PLLADIV2––––
76543210
–PRES–– CSS
Value Name Description
0 SLOW_CLK Slow Clock is selected
1 MAIN_CLK Main Clock is selected
2 PLLA_CLK PLLA Clock is selected
3 UPLL_CLK UPLL Clock is selected
Value Name Description
0 CLK Selected clock
1 CLK_2 Selected clock divided by 2
2 CLK_4 Selected clock divided by 4
3 CLK_8 Selected clock divided by 8
4 CLK_16 Selected clock divided by 16
5 CLK_32 Selected clock divided by 32
6 CLK_64 Selected clock divided by 64
7 CLK_3 Selected clock divided by 3
PLLADIV2 PLLA Clock Division
0 PLLA clock frequency is divided by 1.
1 PLLA clock frequency is divided by 2.
UPLLDIV2 UPLL Clock Division
0 UPLL clock frequency is divided by 1.
1 UPLL clock frequency is divided by 2.
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28.15.12 PMC USB Clock Register
Name: PMC_USB
Address: 0x400E0638
Access: Read-write
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• USBS: USB Input Clock Selection
0 = USB Clock Input is PLLA.
1 = USB Clock Input is PLLB.
• USBDIV: Divider for USB Clock.
USB Clock is Input clock divided by USBDIV+1.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––– USBDIV
76543210
–––––––USBS
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28.15.13 PMC Programmable Clock Register
Name: PMC_PCKx
Address: 0x400E0640
Access: Read-write
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• CSS: Master Clock Source Selection
• PRES: Programmable Clock Prescaler
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–PRES–CSS
Value Name Description
0 SLOW_CLK Slow Clock is selected
1 MAIN_CLK Main Clock is selected
2 PLLA_CLK PLLA Clock is selected
3 UPLL_CLK UPLL Clock is selected
4MCK Master Clock is selected
Value Name Description
0 CLK Selected clock
1 CLK_2 Selected clock divided by 2
2 CLK_4 Selected clock divided by 4
3 CLK_8 Selected clock divided by 8
4 CLK_16 Selected clock divided by 16
5 CLK_32 Selected clock divided by 32
6 CLK_64 Selected clock divided by 64
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28.15.14 PMC Interrupt Enable Register
Name: PMC_IER
Address: 0x400E0660
Access: Write-only
• MOSCXTS: Main Crystal Oscillator Status Interrupt Enable
• LOCKA: PLLA Lock Interrupt Enable
• MCKRDY: Master Clock Ready Interrupt Enable
• LOCKU: UTMI PLL Lock Interrupt Enable
• PCKRDYx: Programmable Clock Ready x Interrupt Enable
• MOSCSELS: Main Oscillator Selection Status Interrupt Enable
• MOSCRCS: Main On-Chip RC Status Interrupt Enable
• CFDEV: Clock Failure Detector Event Interrupt Enable
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
–––––CFDEVMOSCRCSMOSCSELS
15 14 1312 11 10 9 8
–––––PCKRDY2PCKRDY1PCKRDY0
76543210
– LOCKU– – – MCKRDY – LOCKA MOSCXTS
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28.15.15 PMC Interrupt Disable Register
Name: PMC_IDR
Address: 0x400E0664
Access: Write-only
• MOSCXTS: Main Crystal Oscillator Status Interrupt Disable
• LOCKA: PLLA Lock Interrupt Disable
• MCKRDY: Master Clock Ready Interrupt Disable
• LOCKU: UTMI PLL Lock Interrupt Disable
• PCKRDYx: Programmable Clock Ready x Interrupt Disable
• MOSCSELS: Main Oscillator Selection Status Interrupt Disable
• MOSCRCS: Main On-Chip RC Status Interrupt Disable
• CFDEV: Clock Failure Detector Event Interrupt Disable
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
–––––CFDEVMOSCRCSMOSCSELS
15 14 1312 11 10 9 8
–––––PCKRDY2PCKRDY1PCKRDY0
76543210
– LOCKU– – – MCKRDY – LOCKA MOSCXTS
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28.15.16 PMC Status Register
Name: PMC_SR
Address: 0x400E0668
Access: Read-only
• MOSCXTS: Main XTAL Oscillator Status
0 = Main XTAL oscillator is not stabilized.
1 = Main XTAL oscillator is stabilized.
• LOCKA: PLLA Lock Status
0 = PLLA is not locked
1 = PLLA is locked.
• MCKRDY: Master Clock Status
0 = Master Clock is not ready.
1 = Master Clock is ready.
• LOCKU: UTMI PLL Lock Status
0 = UTMI PLL is not locked
1 = UTMI PLL is locked.
• OSCSELS: Slow Clock Oscillator Selection
0 = Internal slow clock RC oscillator is selected.
1 = External slow clock 32 kHz oscillator is selected.
• PCKRDYx: Programmable Clock Ready Status
0 = Programmable Clock x is not ready.
1 = Programmable Clock x is ready.
• MOSCSELS: Main Oscillator Selection Status
0 = Selection is done.
1 = Selection is in progress.
• MOSCRCS: Main On-Chip RC Oscillator Status
0 = Main on-chip RC oscillator is not stabilized.
1 = Main on-chip RC oscillator is stabilized.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
– – – FOS CFDS CFDEV MOSCRCS MOSCSELS
15 14 1312 11 10 9 8
–––––PCKRDY2PCKRDY1PCKRDY0
76543210
OSCSELS LOCKU– – – MCKRDY – LOCKA MOSCXTS
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• CFDEV: Clock Failure Detector Event
0 = No clock failure detection of the main on-chip RC oscillator clock has occurred since the last read of PMC_SR.
1 = At least one clock failure detection of the main on-chip RC oscillator clock has occurred since the last read of PMC_SR.
• CFDS: Clock Failure Detector Status
0 = A clock failure of the main on-chip RC oscillator clock is not detected.
1 = A clock failure of the main on-chip RC oscillator clock is detected.
• FOS: Clock Failure Detector Fault Output Status
0 = The fault output of the clock failure detector is inactive.
1 = The fault output of the clock failure detector is active.
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28.15.17 PMC Interrupt Mask Register
Name: PMC_IMR
Address: 0x400E066C
Access: Read-only
• MOSCXTS: Main Crystal Oscillator Status Interrupt Mask
• LOCKA: PLLA Lock Interrupt Mask
• MCKRDY: Master Clock Ready Interrupt Mask
• LOCKU: UTMI PLL Lock Interrupt Mask
• PCKRDYx: Programmable Clock Ready x Interrupt Mask
• MOSCSELS: Main Oscillator Selection Status Interrupt Mask
• MOSCRCS: Main On-Chip RC Status Interrupt Mask
• CFDEV: Clock Failure Detector Event Interrupt Mask
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
–––––CFDEVMOSCRCSMOSCSELS
15 14 1312 11 10 9 8
–––––PCKRDY2PCKRDY1PCKRDY0
76543210
– LOCKU– – – MCKRDY – LOCKA MOSCXTS
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28.15.18 PMC Fast Startup Mode Register
Name: PMC_FSMR
Address: 0x400E0670
Access: Read-write
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• FSTT0 - FSTT15: Fast Startup Input Enable 0 to 15
0 = The corresponding wake up input has no effect on the Power Management Controller.
1 = The corresponding wake up input enables a fast restart signal to the Power Management Controller.
• RTTAL: RTT Alarm Enable
0 = The RTT alarm has no effect on the Power Management Controller.
1 = The RTT alarm enables a fast restart signal to the Power Management Controller.
• RTCAL: RTC Alarm Enable
0 = The RTC alarm has no effect on the Power Management Controller.
1 = The RTC alarm enables a fast restart signal to the Power Management Controller.
• USBAL: USB Alarm Enable
0 = The USB alarm has no effect on the Power Management Controller.
1 = The USB alarm enables a fast restart signal to the Power Management Controller.
• LPM: Low Power Mode
0 = The WaitForInterrupt (WFI) or WaitForEvent (WFE) instruction of the processor makes the processor enter Sleep
Mode.
1 = The WaitForEvent (WFE) instruction of the processor makes the system to enter in Wait Mode.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– – – LPM – USBAL RTCAL RTTAL
15 14 13 12 11 10 9 8
FSTT15 FSTT14 FSTT13 FSTT12 FSTT11 FSTT10 FSTT9 FSTT8
76543210
FSTT7 FSTT6 FSTT5 FSTT4 FSTT3 FSTT2 FSTT1 FSTT0
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28.15.19 PMC Fast Startup Polarity Register
Name: PMC_FSPR
Address: 0x400E0674
Access: Read-write
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• FSTPx: Fast Startup Input Polarityx
Defines the active polarity of the corresponding wake up input. If the corresponding wake up input is enabled and at the
FSTP level, it enables a fast restart signal.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
FSTP15 FSTP14 FSTP13 FSTP12 FSTP11 FSTP10 FSTP9 FSTP8
76543210
FSTP7 FSTP6 FSTP5 FSTP4 FSTP3 FSTP2 FSTP1 FSTP0
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28.15.20 PMC Fault Output Clear Register
Name: PMC_FOCR
Address: 0x400E0678
Access: Write-only
• FOCLR: Fault Output Clear
Clears the clock failure detector fault output.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––FOCLR
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28.15.21 PMC Write Protect Mode Register
Name: PMC_WPMR
Address: 0x400E06E4
Access: Read-write
Reset: See Table 28-3
• WPEN: Write Protect Enable
0 = Disables the Write Protect if WPKEY corresponds to 0x504D43 (“PMC” in ASCII).
1 = Enables the Write Protect if WPKEY corresponds to 0x504D43 (“PMC” in ASCII).
Protects the registers:
“PMC System Clock Enable Register”
“PMC System Clock Disable Register”
“PMC Peripheral Clock Enable Register 0”
“PMC Peripheral Clock Disable Register 0”
“PMC Clock Generator Main Oscillator Register”
“PMC Clock Generator PLLA Register”
“PMC Master Clock Register”
“PMC USB Clock Register”
“PMC Programmable Clock Register”
“PMC Fast Startup Mode Register”
“PMC Fast Startup Polarity Register”
“PMC Peripheral Clock Enable Register 1”
“PMC Peripheral Clock Disable Register 1”
• WPKEY: Write Protect KEY
Should be written at value 0x504D43 (“PMC” in ASCII). Writing any other value in this field aborts the write operation of the
WPEN bit. Always reads as 0.
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
–––––––WPEN
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28.15.22 PMC Write Protect Status Register
Name: PMC_WPSR
Address: 0x400E06E8
Access: Read-only
Reset: See Table 28-3
• WPVS: Write Protect Violation Status
0 = No Write Protect Violation has occurred since the last read of the PMC_WPSR register.
1 = A Write Protect Violation has occurred since the last read of the PMC_WPSR register. If this violation is an unauthor-
ized attempt to write a protected register, the associated violation is reported into field WPVSRC.
• WPVSRC: Write Protect Violation Source
When WPVS is active, this field indicates the write-protected register (through address offset or code) in which a write
access has been attempted.
Reading PMC_WPSR automatically clears all fields.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
WPVSRC
15 14 13 12 11 10 9 8
WPVSRC
76543210
–––––––WPVS
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28.15.23 PMC Peripheral Clock Enable Register 1
Name: PMC_PCER1
Address: 0x400E0700
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” .
• PIDx: Peripheral Clock x Enable
0 = No effect.
1 = Enables the corresponding peripheral clock.
Notes: 1. To get PIDx, refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet.
2. Programming the control bits of the Peripheral ID that are not implemented has no effect on the behavior of the PMC.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––PID44PID43PID42 PID41 PID40
76543210
PID39PID38 PID37PID36PID35PID34PID33 PID32
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28.15.24 PMC Peripheral Clock Disable Register 1
Name: PMC_PCDR1
Address: 0x400E0704
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PMC Write Protect Mode Register” on page 561.
• PIDx: Peripheral Clock x Disable
0 = No effect.
1 = Disables the corresponding peripheral clock.
Note: To get PIDx, refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––PID44PID43PID42 PID41 PID40
76543210
PID39PID38 PID37PID36PID35PID34PID33 PID32
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28.15.25 PMC Peripheral Clock Status Register 1
Name: PMC_PCSR1
Address: 0x400E0708
Access: Read-only
• PIDx: Peripheral Clock x Status
0 = The corresponding peripheral clock is disabled.
1 = The corresponding peripheral clock is enabled.
Note: To get PIDx, refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––PID44PID43PID42 PID41 PID40
76543210
PID39PID38 PID37PID36PID35PID34PID33 PID32
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28.15.26 PMC Peripheral Control Register
Name: PMC_PCR
Address: 0x400E070C
Access: Read-write
• PID: Peripheral ID
Peripheral ID selection from PID2 to PID63
PID2 to PID63 refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet.
Not all PID can be configured with divided clock.
Only the following PID can be configured with divided clock: CAN0, CAN1.
•CMD: Command
0 = Read mode.
1 = Write mode.
• DIV: Divisor Value
DIV must not be changed while peripheral is in use or when the peripheral clock is enabled.
To change the clock division factor (DIV) of a peripheral, its clock must first be disabled by writing either EN to 0 for the cor-
responding PID (DIV must be kept the same if this method is used), or writing to PMC_PCDR register. Then a second write
must be performed into PMC_PCR with the new value of DIV and a third write must be performed to enable the peripheral
clock (either by using PMC_PCR or PMC_PCER register).
• EN: Enable
0 = Selected Peripheral clock is disabled.
1 = Selected Peripheral clock is enabled.
3130292827 26 25 24
–––EN––––
2322 21 20 19 1817 16
–––––– DIV
15 14 1312 11 10 9 8
–––
CMD ––––
76543210
–– PID
Value Name Description
0 PERIPH_DIV_MCK Peripheral clock is MCK
1 PERIPH_DIV2_MCK Peripheral clock is MCK/2
2 PERIPH_DIV4_MCK Peripheral clock is MCK/4
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29. Chip Identifier (CHIPID)
29.1 Description
Chip Identifier registers permit recognition of the device and its revision. These registers provide the sizes and
types of the on-chip memories, as well as the set of embedded peripherals.
Two chip identifier registers are embedded: CHIPID_CIDR (Chip ID Register) and CHIPID_EXID (Extension ID).
Both registers contain a hard-wired value that is read-only. The first register contains the following fields:
EXT - shows the use of the extension identifier register
NVPTYP and NVPSIZ - identifies the type of embedded non-volatile memory and its size
ARCH - identifies the set of embedded peripherals
SRAMSIZ - indicates the size of the embedded SRAM
EPROC - indicates the embedded ARM processor
VERSION - gives the revision of the silicon
The second register is device-dependent and reads 0 if the bit EXT is 0.
29.2 Embedded Characteristics
Chip ID Registers
̶Identification of the Device Revision, Sizes of the Embedded Memories, Set of Peripherals,
Embedded Processor
Note: 1. This device is not commercially available. Mounted only on the SAM3X-EK evaluation kit.
Table 29-1. ATSAM3A/X Chip IDs Register
Chip Name CHIPID_CIDR CHIPID_EXID
ATSAM3X8H(1) (Rev A) 0x286E0A60 0x0
ATSAM3X8E (Rev A) 0x285E0A60 0x0
ATSAM3X4E (Rev A) 0x285B0960 0x0
ATSAM3X8C (Rev A) 0x284E0A60 0x0
ATSAM3X4C (Rev A) 0x284B0960 0x0
ATSAM3A8C (Rev A) 0x283E0A60 0x0
ATSAM3A4C (Rev A) 0x283B0960 0x0
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29.3 Chip Identifier (CHIPID) User Interface
Table 29-2. Register Mapping
Offset Register Name Access Reset
0x0 Chip ID Register CHIPID_CIDR Read-only –
0x4 Chip ID Extension Register CHIPID_EXID Read-only –
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29.3.1 Chip ID Register
Name: CHIPID_CIDR
Address: 0x400E0940
Access: Read-only
• VERSION: Version of the Device
Current version of the device.
• EPROC: Embedded Processor
• NVPSIZ: Nonvolatile Program Memory Size
3130292827 26 25 24
EXT NVPTYP ARCH
2322 21 20 19 1817 16
ARCH SRAMSIZ
15 14 1312 11 10 9 8
NVPSIZ2 NVPSIZ
76543210
EPROC VERSION
Value Name Description
1 ARM946ES ARM946ES
2 ARM7TDMI ARM7TDMI
3 CM3 Cortex-M3
4 ARM920T ARM920T
5 ARM926EJS ARM926EJS
6 CA5 Cortex-A5
Value Name Description
0 NONE None
18K 8K bytes
2 16K 16K bytes
3 32K 32K bytes
4 Reserved
5 64K 64K bytes
6 Reserved
7 128K 128K bytes
8 Reserved
9 256K 256K bytes
10 512K 512K bytes
11 Reserved
12 1024K 1024K bytes
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• NVPSIZ2 Second Nonvolatile Program Memory Size
• SRAMSIZ: Internal SRAM Size
13 Reserved
14 2048K 2048K bytes
15 Reserved
Value Name Description
0 NONE None
18K 8K bytes
2 16K 16K bytes
3 32K 32K bytes
4 Reserved
5 64K 64K bytes
6 Reserved
7 128K 128K bytes
8 Reserved
9 256K 256K bytes
10 512K 512K bytes
11 Reserved
12 1024K 1024K bytes
13 Reserved
14 2048K 2048K bytes
15 Reserved
Value Name Description
0 48K 48K bytes
11K 1K bytes
22K 2K bytes
36K 6K bytes
4 24K 24K bytes
54K 4K bytes
6 80K 80K bytes
7 160K 160K bytes
88K 8K bytes
9 16K 16K bytes
10 32K 32K bytes
11 64K 64K bytes
12 128K 128K bytes
Value Name Description
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• ARCH: Architecture Identifier
13 256K 256K bytes
14 96K 96K bytes
15 512K 512K bytes
Value Name Description
0x19 AT91SAM9xx AT91SAM9xx Series
0x29 AT91SAM9XExx AT91SAM9XExx Series
0x34 AT91x34 AT91x34 Series
0x37 CAP7 CAP7 Series
0x39 CAP9 CAP9 Series
0x3B CAP11 CAP11 Series
0x40 AT91x40 AT91x40 Series
0x42 AT91x42 AT91x42 Series
0x55 AT91x55 AT91x55 Series
0x60 AT91SAM7Axx AT91SAM7Axx Series
0x61 AT91SAM7AQxx AT91SAM7AQxx Series
0x63 AT91x63 AT91x63 Series
0x70 AT91SAM7Sxx AT91SAM7Sxx Series
0x71 AT91SAM7XCxx AT91SAM7XCxx Series
0x72 AT91SAM7SExx AT91SAM7SExx Series
0x73 AT91SAM7Lxx AT91SAM7Lxx Series
0x75 AT91SAM7Xxx AT91SAM7Xxx Series
0x76 AT91SAM7SLxx AT91SAM7SLxx Series
0x80 SAM3UxC SAM3UxC Series (100-pin version)
0x81 SAM3UxE SAM3UxE Series (144-pin version)
0x83 SAM3AxC SAM3AxC Series (100-pin version)
0x84 SAM3XxC SAM3XxC Series (100-pin version)
0x85 SAM3XxE SAM3XxE Series (144-pin version)
0x86 SAM3XxG SAM3XxG Series (217-pin version)
0x88 SAM3SxA SAM3SxA Series (48-pin version)
0x89 SAM3SxB SAM3SxB Series (64-pin version)
0x8A SAM3SxC SAM3SxC Series (100-pin version)
0x92 AT91x92 AT91x92 Series
0x93 SAM3NxA SAM3NxA Series (48-pin version)
0x94 SAM3NxB SAM3NxB Series (64-pin version)
0x95 SAM3NxC SAM3NxC Series (100-pin version)
0x98 SAM3SDxA SAM3SDxA Series (48-pin version)
0x99 SAM3SDxB SAM3SDxB Series (64-pin version)
Value Name Description
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• NVPTYP: Nonvolatile Program Memory Type
• EXT: Extension Flag
0 = Chip ID has a single register definition without extension
1 = An extended Chip ID exists.
0x9A SAM3SDxC SAM3SDxC Series (100-pin version)
0xA5 SAM5A SAM5A
0xF0 AT75Cxx AT75Cxx Series
Value Name Description
0ROM ROM
1 ROMLESS ROMless or on-chip Flash
4 SRAM SRAM emulating ROM
2 FLASH Embedded Flash Memory
3 ROM_FLASH
ROM and Embedded Flash Memory
NVPSIZ is ROM size
NVPSIZ2 is Flash size
Value Name Description
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29.3.2 Chip ID Extension Register
Name: CHIPID_EXID
Address: 0x400E0944
Access: Read-only
• EXID: Chip ID Extension
Reads 0 if the bit EXT in CHIPID_CIDR is 0.
3130292827 26 25 24
EXID
2322 21 20 19 1817 16
EXID
15 14 1312 11 10 9 8
EXID
76543210
EXID
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30. Synchronous Serial Controller (SSC)
30.1 Description
The Atmel Synchronous Serial Controller (SSC) provides a synchronous communication link with external devices.
It supports many serial synchronous communication protocols generally used in audio and telecom applications
such as I2S, Short Frame Sync, Long Frame Sync, etc.
The SSC contains an independent receiver and transmitter and a common clock divider. The receiver and the
transmitter each interface with three signals: the TD/RD signal for data, the TK/RK signal for the clock and the
TF/RF signal for the Frame Sync. The transfers can be programmed to start automatically or on different events
detected on the Frame Sync signal.
The SSC’s high-level of programmability and its use of DMA permit a continuous high bit rate data transfer without
processor intervention.
Featuring connection to the DMA, the SSC permits interfacing with low processor overhead to the following:
CODEC’s in master or slave mode
DAC through dedicated serial interface, particularly I2S
Magnetic card reader
30.2 Embedded Characteristics
Provides Serial Synchronous Communication Links Used in Audio and Telecom Applications
Contains an Independent Receiver and Transmitter and a Common Clock Divider
Interfaced with the DMA Controller (DMAC) to Reduce Processor Overhead
Offers a Configurable Frame Sync and Data Length
Receiver and Transmitter Can be Programmed to Start Automatically or on Detection of Different Events on
the Frame Sync Signal
Receiver and Transmitter Include a Data Signal, a Clock Signal and a Frame Synchronization Signal
$3 $3 WL
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30.3 Block Diagram
Figure 30-1. Block Diagram
30.4 Application Block Diagram
Figure 30-2. Application Block Diagram
SSC Interface PIO
DMA
APB Bridge
MCK
System
Bus
Peripheral
Bus TF
TK
TD
RF
RK
RD
Interrupt Control
SSC Interrupt
PMC
Interrupt
Management
Power
Management Test
Management
SSC
Serial AUDIO
OS or RTOS Driver
Codec Frame
Management Line Interface
Time Slot
Management
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30.5 Pin Name List
30.6 Product Dependencies
30.6.1 I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines.
Before using the SSC receiver, the PIO controller must be configured to dedicate the SSC receiver I/O lines to the
SSC peripheral mode.
Before using the SSC transmitter, the PIO controller must be configured to dedicate the SSC transmitter I/O lines
to the SSC peripheral mode.
30.6.2 Power Management
The SSC is not continuously clocked. The SSC interface may be clocked through the Power Management
Controller (PMC), therefore the programmer must first configure the PMC to enable the SSC clock.
30.6.3 Interrupt
The SSC interface has an interrupt line connected to the Nested Vector Interrupt Controller (NVIC). Handling
interrupts requires programming the NVIC before configuring the SSC.
All SSC interrupts can be enabled/disabled configuring the SSC Interrupt mask register. Each pending and
unmasked SSC interrupt will assert the SSC interrupt line. The SSC interrupt service routine can get the interrupt
origin by reading the SSC interrupt status register.
Table 30-1. I/O Lines Description
Pin Name Pin Description Type
RF Receiver Frame Synchro Input/Output
RK Receiver Clock Input/Output
RD Receiver Data Input
TF Transmitter Frame Synchro Input/Output
TK Transmitter Clock Input/Output
TD Transmitter Data Output
Table 30-2. I/O Lines
Instance Signal I/O Line Peripheral
SSC RD PB18 A
SSC RF PB17 A
SSC RK PB19 A
SSC TD PA16 B
SSC TF PA15 B
SSC TK PA14 B
Table 30-3. Peripheral IDs
Instance ID
SSC 26
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30.7 Functional Description
This chapter contains the functional description of the following: SSC Functional Block, Clock Management, Data
format, Start, Transmitter, Receiver and Frame Sync.
The receiver and transmitter operate separately. However, they can work synchronously by programming the
receiver to use the transmit clock and/or to start a data transfer when transmission starts. Alternatively, this can be
done by programming the transmitter to use the receive clock and/or to start a data transfer when reception starts.
The transmitter and the receiver can be programmed to operate with the clock signals provided on either the TK or
RK pins. This allows the SSC to support many slave-mode data transfers. The maximum clock speed allowed on
the TK and RK pins is the master clock divided by 2.
Figure 30-3. SSC Functional Block Diagram
30.7.1 Clock Management
The transmitter clock can be generated by:
an external clock received on the TK I/O pad
the receiver clock
the internal clock divider
NVIC
Frame Sync
Controller
Clock Output
Controller
Data
Controller
Start
Selector
Start
Selector
RF
RXEN
RC0R
TX Start
TXEN
TF
RX Start
TX Start
Interrupt Control
User
Interface
APB
MCK
Receive Clock
Controller
TX Clock
RK Input
Transmit Clock
Controller
Transmit Shift Register
Transmit Sync
Holding Register
Transmit Holding
Register
RX clock
TX clock
TK Input
RD
RF
RK
Clock Output
Controller
Frame Sync
Controller
Receive Shift Register
Receive Sync
Holding Register
Receive Holding
Register
TD
TF
TK
RX Clock
Receiver
Transmitter
Data
Controller
Clock
Divider
RX Start
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The receiver clock can be generated by:
an external clock received on the RK I/O pad
the transmitter clock
the internal clock divider
Furthermore, the transmitter block can generate an external clock on the TK I/O pad, and the receiver block can
generate an external clock on the RK I/O pad.
This allows the SSC to support many Master and Slave Mode data transfers.
30.7.1.1 Clock Divider
Figure 30-4. Divided Clock Block Diagram
The Master Clock divider is determined by the 12-bit field DIV counter and comparator (so its maximal value is
4095) in the Clock Mode Register SSC_CMR, allowing a Master Clock division by up to 8190. The Divided Clock is
provided to both the Receiver and Transmitter. When this field is programmed to 0, the Clock Divider is not used
and remains inactive.
When DIV is set to a value equal to or greater than 1, the Divided Clock has a frequency of Master Clock divided
by 2 times DIV. Each level of the Divided Clock has a duration of the Master Clock multiplied by DIV. This ensures
a 50% duty cycle for the Divided Clock regardless of whether the DIV value is even or odd.
Figure 30-5. Divided Clock Generation
Table 30-4.
Maximum Minimum
MCK / 2 MCK / 8190
MCK
Divided Clock
Clock Divider
/ 2 12-bit Counter
SSC_CMR
Master Clock
Divided Clock
DIV = 1
Master Clock
Divided Clock
DIV = 3
Divided Clock Frequency = MCK/2
Divided Clock Frequency = MCK/6
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30.7.1.2 Transmitter Clock Management
The transmitter clock is generated from the receiver clock or the divider clock or an external clock scanned on the
TK I/O pad. The transmitter clock is selected by the CKS field in SSC_TCMR (Transmit Clock Mode Register).
Transmit Clock can be inverted independently by the CKI bits in SSC_TCMR.
The transmitter can also drive the TK I/O pad continuously or be limited to the actual data transfer. The clock
output is configured by the SSC_TCMR register. The Transmit Clock Inversion (CKI) bits have no effect on the
clock outputs. Programming the TCMR register to select TK pin (CKS field) and at the same time Continuous
Transmit Clock (CKO field) might lead to unpredictable results.
Figure 30-6. Transmitter Clock Management
30.7.1.3 Receiver Clock Management
The receiver clock is generated from the transmitter clock or the divider clock or an external clock scanned on the
RK I/O pad. The Receive Clock is selected by the CKS field in SSC_RCMR (Receive Clock Mode Register).
Receive Clocks can be inverted independently by the CKI bits in SSC_RCMR.
The receiver can also drive the RK I/O pad continuously or be limited to the actual data transfer. The clock output
is configured by the SSC_RCMR register. The Receive Clock Inversion (CKI) bits have no effect on the clock
outputs. Programming the RCMR register to select RK pin (CKS field) and at the same time Continuous Receive
Clock (CKO field) can lead to unpredictable results.
TK (pin)
Receiver
Clock
Divider
Clock
CKS
CKO Data Transfer
CKI CKG
Transmitter
Clock
Clock
Output
MUX Tri _state
Controller
Tri -state
Controller
INV
MUX
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Figure 30-7. Receiver Clock Management
30.7.1.4 Serial Clock Ratio Considerations
The Transmitter and the Receiver can be programmed to operate with the clock signals provided on either the TK
or RK pins. This allows the SSC to support many slave-mode data transfers. In this case, the maximum clock
speed allowed on the RK pin is:
̶Master Clock divided by 2 if Receiver Frame Synchro is input
̶Master Clock divided by 3 if Receiver Frame Synchro is output
In addition, the maximum clock speed allowed on the TK pin is:
̶Master Clock divided by 6 if Transmit Frame Synchro is input
̶Master Clock divided by 2 if Transmit Frame Synchro is output
RK (pin)
Transmitter
Clock
Divider
Clock
CKS
CKO Data Transfer
CKI CKG
Receiver
Clock
Clock
Output
MUX Tri -state
Controller
Tri -state
Controller
INV
MUX
TX Stan AtmeL
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30.7.2 Transmitter Operations
A transmitted frame is triggered by a start event and can be followed by synchronization data before data
transmission.
The start event is configured by setting the Transmit Clock Mode Register (SSC_TCMR). See “Start” on page 582.
The frame synchronization is configured setting the Transmit Frame Mode Register (SSC_TFMR). See “Frame
Sync” on page 584.
To transmit data, the transmitter uses a shift register clocked by the transmitter clock signal and the start mode
selected in the SSC_TCMR. Data is written by the application to the SSC_THR register then transferred to the shift
register according to the data format selected.
When both the SSC_THR and the transmit shift register are empty, the status flag TXEMPTY is set in SSC_SR.
When the Transmit Holding register is transferred in the Transmit shift register, the status flag TXRDY is set in
SSC_SR and additional data can be loaded in the holding register.
Figure 30-8. Transmitter Block Diagram
Transmit Shift Register
TD
SSC_TFMR.FSLENSSC_TFMR.DATLEN
SSC_TCMR.STTDLY
SSC_TFMR.FSDEN
SSC_TFMR.DATNB
SSC_TFMR.DATDEF
SSC_TFMR.MSBF
SSC_TCMR.STTDLY != 0
SSC_TFMR.FSDEN
10
TX Controller
SSC_TCMR.START
RF
Start
Selector
TXEN
RX Start
TXEN
RF
Start
Selector
RXEN
RC0R
TX Start TX Start
Transmitter Clock
TX Controller counter reached STTDLY
SSC_RCMR.START
SSC_THR SSC_TSHR
SSC_CRTXEN
SSC_SRTXEN
SSC_CRTXDIS
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30.7.3 Receiver Operations
A received frame is triggered by a start event and can be followed by synchronization data before data
transmission.
The start event is configured setting the Receive Clock Mode Register (SSC_RCMR). See “Start” on page 582.
The frame synchronization is configured setting the Receive Frame Mode Register (SSC_RFMR). See “Frame
Sync” on page 584.
The receiver uses a shift register clocked by the receiver clock signal and the start mode selected in the
SSC_RCMR. The data is transferred from the shift register depending on the data format selected.
When the receiver shift register is full, the SSC transfers this data in the holding register, the status flag RXRDY is
set in SSC_SR and the data can be read in the receiver holding register. If another transfer occurs before read of
the RHR register, the status flag OVERUN is set in SSC_SR and the receiver shift register is transferred in the
RHR register.
Figure 30-9. Receiver Block Diagram
30.7.4 Start
The transmitter and receiver can both be programmed to start their operations when an event occurs, respectively
in the Transmit Start Selection (START) field of SSC_TCMR and in the Receive Start Selection (START) field of
SSC_RCMR.
Under the following conditions the start event is independently programmable:
Continuous. In this case, the transmission starts as soon as a word is written in SSC_THR and the reception
starts as soon as the Receiver is enabled.
Synchronously with the transmitter/receiver
On detection of a falling/rising edge on TF/RF
On detection of a low level/high level on TF/RF
On detection of a level change or an edge on TF/RF
A start can be programmed in the same manner on either side of the Transmit/Receive Clock Register
(RCMR/TCMR). Thus, the start could be on TF (Transmit) or RF (Receive).
Moreover, the Receiver can start when data is detected in the bit stream with the Compare Functions.
SSC_RFMR.MSBF
SSC_RFMR.DATNB
SSC_TCMR.START
SSC_RCMR.START
SSC_RHRSSC_RSHR
SSC_RFMR.FSLEN SSC_RFMR.DATLEN
RX Controller counter reached STTDLY
RX Controller
RD
SSC_CR.RXEN
SSC_CR.RXDIS
SSC_SR.RXEN
Receiver Clock
RF
TXEN
RX Start
RF
RXEN
RC0R
SSC_RCMR.STTDLY != 0
Receive Shift Register
Start
Selector Start
Selector
RX Start
load load
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Detection on TF/RF input/output is done by the field FSOS of the Transmit/Receive Frame Mode Register
(TFMR/RFMR).
Figure 30-10. Transmit Start Mode
Figure 30-11. Receive Pulse/Edge Start Modes
X
TK
TF
(Input)
TD
(Output)
TD
(Output)
TD
(Output)
TD
(Output)
TD
(Output)
TD
(Output)
X BO B1
XBO B1
BO B1
BO B1
BO B1BO B1
BO B1B1
BO
X
X
X
STTDLY
STTDLY
STTDLY
STTDLY
STTDLY
STTDLY
Start = Falling Edge on TF
Start = Rising Edge on TF
Start = Low Level on TF
Start = High Level on TF
Start = Any Edge on TF
Start = Level Change on TF
X
RK
RF
(Input)
RD
(Input)
RD
(Input)
RD
(Input)
RD
(Input)
RD
(Input)
RD
(Input)
X BO B1
XBO B1
BO B1
BO B1
BO B1BO B1
BO B1B1
BO
X
X
X
STTDLY
STTDLY
STTDLY
STTDLY
STTDLY
STTDLY
Start = Falling Edge on RF
Start = Rising Edge on RF
Start = Low Level on RF
Start = High Level on RF
Start = Any Edge on RF
Start = Level Change on RF
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30.7.5 Frame Sync
The Transmitter and Receiver Frame Sync pins, TF and RF, can be programmed to generate different kinds of
frame synchronization signals. The Frame Sync Output Selection (FSOS) field in the Receive Frame Mode
Register (SSC_RFMR) and in the Transmit Frame Mode Register (SSC_TFMR) are used to select the required
waveform.
Programmable low or high levels during data transfer are supported.
Programmable high levels before the start of data transfers or toggling are also supported.
If a pulse waveform is selected, the Frame Sync Length (FSLEN) field in SSC_RFMR and SSC_TFMR programs
the length of the pulse, from 1 bit time up to 256 bit time.
The periodicity of the Receive and Transmit Frame Sync pulse output can be programmed through the Period
Divider Selection (PERIOD) field in SSC_RCMR and SSC_TCMR.
30.7.5.1 Frame Sync Data
Frame Sync Data transmits or receives a specific tag during the Frame Sync signal.
During the Frame Sync signal, the Receiver can sample the RD line and store the data in the Receive Sync
Holding Register and the transmitter can transfer Transmit Sync Holding Register in the Shifter Register. The data
length to be sampled/shifted out during the Frame Sync signal is programmed by the FSLEN field in
SSC_RFMR/SSC_TFMR and has a maximum value of 16.
Concerning the Receive Frame Sync Data operation, if the Frame Sync Length is equal to or lower than the delay
between the start event and the actual data reception, the data sampling operation is performed in the Receive
Sync Holding Register through the Receive Shift Register.
The Transmit Frame Sync Operation is performed by the transmitter only if the bit Frame Sync Data Enable
(FSDEN) in SSC_TFMR is set. If the Frame Sync length is equal to or lower than the delay between the start event
and the actual data transmission, the normal transmission has priority and the data contained in the Transmit Sync
Holding Register is transferred in the Transmit Register, then shifted out.
30.7.5.2 Frame Sync Edge Detection
The Frame Sync Edge detection is programmed by the FSEDGE field in SSC_RFMR/SSC_TFMR. This sets the
corresponding flags RXSYN/TXSYN in the SSC Status Register (SSC_SR) on frame synchro edge detection
(signals RF/TF).
30.7.6 Receive Compare Modes
Figure 30-12. Receive Compare Modes
30.7.6.1 Compare Functions
Length of the comparison patterns (Compare 0, Compare 1) and thus the number of bits they are compared to is
defined by FSLEN, but with a maximum value of 16 bits. Comparison is always done by comparing the last bits
received with the comparison pattern. Compare 0 can be one start event of the Receiver. In this case, the receiver
compares at each new sample the last bits received at the Compare 0 pattern contained in the Compare 0
CMP0 CMP3
CMP2
CMP1 Ignored B0 B2
B1
Start
RK
RD
(Input)
FSLEN
Up to 16 Bits
(4 in This Example)
STDLY DATLEN
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Register (SSC_RC0R). When this start event is selected, the user can program the Receiver to start a new data
transfer either by writing a new Compare 0, or by receiving continuously until Compare 1 occurs. This selection is
done with the bit (STOP) in SSC_RCMR.
30.7.7 Data Format
The data framing format of both the transmitter and the receiver are programmable through the Transmitter Frame
Mode Register (SSC_TFMR) and the Receiver Frame Mode Register (SSC_RFMR). In either case, the user can
independently select:
the event that starts the data transfer (START)
the delay in number of bit periods between the start event and the first data bit (STTDLY)
the length of the data (DATLEN)
the number of data to be transferred for each start event (DATNB).
the length of synchronization transferred for each start event (FSLEN)
the bit sense: most or lowest significant bit first (MSBF)
Additionally, the transmitter can be used to transfer synchronization and select the level driven on the TD pin while
not in data transfer operation. This is done respectively by the Frame Sync Data Enable (FSDEN) and by the Data
Default Value (DATDEF) bits in SSC_TFMR.
Table 30-5. Data Frame Registers
Transmitter Receiver Field Length Comment
SSC_TFMR SSC_RFMR DATLEN Up to 32 Size of word
SSC_TFMR SSC_RFMR DATNB Up to 16 Number of words transmitted in frame
SSC_TFMR SSC_RFMR MSBF Most significant bit first
SSC_TFMR SSC_RFMR FSLEN Up to 16 Size of Synchro data register
SSC_TFMR DATDEF 0 or 1 Data default value ended
SSC_TFMR FSDEN Enable send SSC_TSHR
SSC_TCMR SSC_RCMR PERIOD Up to 512 Frame size
SSC_TCMR SSC_RCMR STTDLY Up to 255 Size of transmit start delay
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Figure 30-13. Transmit and Receive Frame Format in Edge/Pulse Start Modes
Note: 1. Example of input on falling edge of TF/RF.
Figure 30-14. Transmit Frame Format in Continuous Mode
Note: 1. STTDLY is set to 0. In this example, SSC_THR is loaded twice. FSDEN value has no effect on the transmission.
SyncData cannot be output in continuous mode.
Figure 30-15. Receive Frame Format in Continuous Mode
Note: 1. STTDLY is set to 0.
Sync Data Default
STTDLY
Sync Data Ignored
RD
Default
Data
DATLEN
Data
Data
Data
DATLEN
Data
Data Default
Default
Ignored
Sync Data
Sync Data
FSLEN
TF/RF
(1)
Start
Start
From SSC_TSHR
From SSC_THR
From SSC_THR
From SSC_THR
From SSC_THR
To SSC_RHR To SSC_RHRTo SSC_RSHR
TD
(If FSDEN = 0)
TD
(If FSDEN = 1)
DATNB
PERIOD
From DATDEF From DATDEF
From DATDEF From DATDEF
DATLEN
Data
DATLEN
DataDefault
Start
From SSC_THR From SSC_THR
TD
Start: 1. TXEMPTY set to 1
2. Write into the SSC_THR
Data
DATLEN
Data
DATLEN
Start = Enable Receiver
To SSC_RHR To SSC_RHR
RD
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30.7.8 Loop Mode
The receiver can be programmed to receive transmissions from the transmitter. This is done by setting the Loop
Mode (LOOP) bit in SSC_RFMR. In this case, RD is connected to TD, RF is connected to TF and RK is connected
to TK.
30.7.9 Interrupt
Most bits in SSC_SR have a corresponding bit in interrupt management registers.
The SSC can be programmed to generate an interrupt when it detects an event. The interrupt is controlled by
writing SSC_IER (Interrupt Enable Register) and SSC_IDR (Interrupt Disable Register) These registers enable
and disable, respectively, the corresponding interrupt by setting and clearing the corresponding bit in SSC_IMR
(Interrupt Mask Register), which controls the generation of interrupts by asserting the SSC interrupt line connected
to the NVIC.
Figure 30-16. Interrupt Block Diagram
SSC_IMR
Interrupt
Control
SSC Interrupt
Set
RXRDY
OVRUN
RXSYNC
Receiver
Transmitter
TXRDY
TXEMPTY
TXSYNC
Clear
SSC_IER SSC_IDR
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30.8 SSC Application Examples
The SSC can support several serial communication modes used in audio or high speed serial links. Some
standard applications are shown in the following figures. All serial link applications supported by the SSC are not
listed here.
Figure 30-17. Audio Application Block Diagram
Figure 30-18. Codec Application Block Diagram
SSC
RK
RF
RD
TD
TF
TK Clock SCK
Word Select WS
Data SD
I2S
RECEIVER
Clock SCK
Word Select WS
Data SD
Right Channel
Left Channel
MSBMSB
LSB
SSC
RK
RF
RD
TD
TF
TK Serial Data Clock (SCLK)
Frame sync (FSYNC)
Serial Data Out
Serial Data In
CODEC
Serial Data Clock (SCLK)
Frame sync (FSYNC)
Serial Data Out
Serial Data In
First Time Slot
Dstart Dend
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Figure 30-19. Time Slot Application Block Diagram
SSC
RK
RF
RD
TD
TF
TK SCLK
FSYNC
Data Out
Data in
CODEC
First
Time Slot
Serial Data Clock (SCLK)
Frame sync (FSYNC)
Serial Data Out
Serial Data in
CODEC
Second
Time Slot
First Time Slot Second Time Slot
Dstart Dend
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30.8.1 Write Protection Registers
To prevent any single software error that may corrupt SSC behavior, certain address spaces can be write-
protected by setting the WPEN bit in the “SSC Write Protect Mode Register” (SSC_WPMR).
If a write access to the protected registers is detected, then the WPVS flag in the SSC Write Protect Status
Register (US_WPSR) is set and the field WPVSRC indicates in which register the write access has been
attempted.
The WPVS flag is reset by writing the SSC Write Protect Mode Register (SSC_WPMR) with the appropriate
access key, WPKEY.
The protected registers are:
“SSC Clock Mode Register” on page 593
“SSC Receive Clock Mode Register” on page 594
“SSC Receive Frame Mode Register” on page 596
“SSC Transmit Clock Mode Register” on page 598
“SSC Transmit Frame Mode Register” on page 600
“SSC Receive Compare 0 Register” on page 606
“SSC Receive Compare 1 Register” on page 607
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30.9 Synchronous Serial Controller (SSC) User Interface
Table 30-6. Register Mapping
Offset Register Name Access Reset
0x0 Control Register SSC_CR Write-only –
0x4 Clock Mode Register SSC_CMR Read-write 0x0
0x8 Reserved – – –
0xC Reserved – – –
0x10 Receive Clock Mode Register SSC_RCMR Read-write 0x0
0x14 Receive Frame Mode Register SSC_RFMR Read-write 0x0
0x18 Transmit Clock Mode Register SSC_TCMR Read-write 0x0
0x1C Transmit Frame Mode Register SSC_TFMR Read-write 0x0
0x20 Receive Holding Register SSC_RHR Read-only 0x0
0x24 Transmit Holding Register SSC_THR Write-only –
0x28 Reserved – – –
0x2C Reserved – – –
0x30 Receive Sync. Holding Register SSC_RSHR Read-only 0x0
0x34 Transmit Sync. Holding Register SSC_TSHR Read-write 0x0
0x38 Receive Compare 0 Register SSC_RC0R Read-write 0x0
0x3C Receive Compare 1 Register SSC_RC1R Read-write 0x0
0x40 Status Register SSC_SR Read-only 0x000000CC
0x44 Interrupt Enable Register SSC_IER Write-only –
0x48 Interrupt Disable Register SSC_IDR Write-only –
0x4C Interrupt Mask Register SSC_IMR Read-only 0x0
0xE4 Write Protect Mode Register SSC_WPMR Read-write 0x0
0xE8 Write Protect Status Register SSC_WPSR Read-only 0x0
0x50-0xFC Reserved – – –
0x100- 0x124 Reserved – – –
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30.9.1 SSC Control Register
Name: SSC_CR
Address: 0x40004000
Access: Write-only
• RXEN: Receive Enable
0 = No effect.
1 = Enables Receive if RXDIS is not set.
• RXDIS: Receive Disable
0 = No effect.
1 = Disables Receive. If a character is currently being received, disables at end of current character reception.
• TXEN: Transmit Enable
0 = No effect.
1 = Enables Transmit if TXDIS is not set.
• TXDIS: Transmit Disable
0 = No effect.
1 = Disables Transmit. If a character is currently being transmitted, disables at end of current character transmission.
• SWRST: Software Reset
0 = No effect.
1 = Performs a software reset. Has priority on any other bit in SSC_CR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
SWRST–––––TXDISTXEN
76543210
––––––RXDISRXEN
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30.9.2 SSC Clock Mode Register
Name: SSC_CMR
Address: 0x40004004
Access: Read-write
This register can only be written if the WPEN bit is cleared in “SSC Write Protect Mode Register” .
• DIV: Clock Divider
0 = The Clock Divider is not active.
Any Other Value: The Divided Clock equals the Master Clock divided by 2 times DIV. The maximum bit rate is MCK/2. The
minimum bit rate is MCK/2 x 4095 = MCK/8190.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––– DIV
76543210
DIV
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30.9.3 SSC Receive Clock Mode Register
Name: SSC_RCMR
Address: 0x40004010
Access: Read-write
This register can only be written if the WPEN bit is cleared in “SSC Write Protect Mode Register” .
• CKS: Receive Clock Selection
• CKO: Receive Clock Output Mode Selection
• CKI: Receive Clock Inversion
0 = The data inputs (Data and Frame Sync signals) are sampled on Receive Clock falling edge. The Frame Sync signal
output is shifted out on Receive Clock rising edge.
1 = The data inputs (Data and Frame Sync signals) are sampled on Receive Clock rising edge. The Frame Sync signal
output is shifted out on Receive Clock falling edge.
CKI affects only the Receive Clock and not the output clock signal.
31 30 29 28 27 26 25 24
PERIOD
23 22 21 20 19 18 17 16
STTDLY
15 14 13 12 11 10 9 8
– – – STOP START
76543210
CKG CKI CKO CKS
Value Name Description
0 MCK Divided Clock
1TK TK Clock signal
2RK RK pin
3Reserved
Value Name Description RK Pin
0 NONE None Input-only
1 CONTINUOUS Continuous Receive Clock Output
2 TRANSFER Receive Clock only during data transfers Output
3-7 Reserved
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• CKG: Receive Clock Gating Selection
• START: Receive Start Selection
• STOP: Receive Stop Selection
0 = After completion of a data transfer when starting with a Compare 0, the receiver stops the data transfer and waits for a
new compare 0.
1 = After starting a receive with a Compare 0, the receiver operates in a continuous mode until a Compare 1 is detected.
• STTDLY: Receive Start Delay
If STTDLY is not 0, a delay of STTDLY clock cycles is inserted between the start event and the actual start of reception.
When the Receiver is programmed to start synchronously with the Transmitter, the delay is also applied.
Note: It is very important that STTDLY be set carefully. If STTDLY must be set, it should be done in relation to TAG
(Receive Sync Data) reception.
• PERIOD: Receive Period Divider Selection
This field selects the divider to apply to the selected Receive Clock in order to generate a new Frame Sync Signal. If 0, no
PERIOD signal is generated. If not 0, a PERIOD signal is generated each 2 x (PERIOD+1) Receive Clock.
Value Name Description RK Pin
0 NONE None Input-only
1 CONTINUOUS Continuous Receive Clock Output
2 TRANSFER Receive Clock only during data transfers Output
3-7 Reserved
Value Name Description
0CONTINUOUS
Continuous, as soon as the receiver is enabled, and
immediately after the end of transfer of the previous data.
1 TRANSMIT Transmit start
2RF_LOW Detection of a low level on RF signal
3 RF_HIGH Detection of a high level on RF signal
4RF_FALLING
Detection of a falling edge on RF signal
5 RF_RISING Detection of a rising edge on RF signal
6 RF_LEVEL Detection of any level change on RF signal
7RF_EDGE Detection of any edge on RF signal
8CMP_0 Compare 0
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30.9.4 SSC Receive Frame Mode Register
Name: SSC_RFMR
Address: 0x40004014
Access: Read-write
This register can only be written if the WPEN bit is cleared in “SSC Write Protect Mode Register” .
• DATLEN: Data Length
0 = Forbidden value (1-bit data length not supported).
Any other value: The bit stream contains DATLEN + 1 data bits.
• LOOP: Loop Mode
0 = Normal operating mode.
1 = RD is driven by TD, RF is driven by TF and TK drives RK.
• MSBF: Most Significant Bit First
0 = The lowest significant bit of the data register is sampled first in the bit stream.
1 = The most significant bit of the data register is sampled first in the bit stream.
• DATNB: Data Number per Frame
This field defines the number of data words to be received after each transfer start, which is equal to (DATNB + 1).
• FSLEN: Receive Frame Sync Length
This field defines the number of bits sampled and stored in the Receive Sync Data Register. When this mode is selected by
the START field in the Receive Clock Mode Register, it also determines the length of the sampled data to be compared to
the Compare 0 or Compare 1 register.
This field is used with FSLEN_EXT to determine the pulse length of the Receive Frame Sync signal.
Pulse length is equal to FSLEN + (FSLEN_EXT * 16) + 1 Receive Clock periods.
31 30 29 28 27 26 25 24
FSLEN_EXT FSLEN_EXT FSLEN_EXT FSLEN_EXT –––FSEDGE
23 22 21 20 19 18 17 16
– FSOS FSLEN
15 14 13 12 11 10 9 8
–––– DATNB
7654 3210
MSBF – LOOP DATLEN
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• FSOS: Receive Frame Sync Output Selection
• FSEDGE: Frame Sync Edge Detection
Determines which edge on Frame Sync will generate the interrupt RXSYN in the SSC Status Register.
• FSLEN_EXT: FSLEN Field Extension
Extends FSLEN field. For details, refer to FSLEN bit description on page 596.
Value Name Description RF Pin
0 NONE None Input-only
1NEGATIVE Negative Pulse Output
2 POSITIVE Positive Pulse Output
3LOW Driven Low during data transfer Output
4 HIGH Driven High during data transfer Output
5 TOGGLING Toggling at each start of data transfer Output
6-7 Reserved Undefined
Value Name Description
0 POSITIVE Positive Edge Detection
1NEGATIVE Negative Edge Detection
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30.9.5 SSC Transmit Clock Mode Register
Name: SSC_TCMR
Address: 0x40004018
Access: Read-write
This register can only be written if the WPEN bit is cleared in “SSC Write Protect Mode Register” .
• CKS: Transmit Clock Selection
• CKO: Transmit Clock Output Mode Selection
• CKI: Transmit Clock Inversion
0 = The data outputs (Data and Frame Sync signals) are shifted out on Transmit Clock falling edge. The Frame sync signal
input is sampled on Transmit clock rising edge.
1 = The data outputs (Data and Frame Sync signals) are shifted out on Transmit Clock rising edge. The Frame sync signal
input is sampled on Transmit clock falling edge.
CKI affects only the Transmit Clock and not the output clock signal.
31 30 29 28 27 26 25 24
PERIOD
23 22 21 20 19 18 17 16
STTDLY
15 14 13 12 11 10 9 8
–––– START
76543210
CKG CKI CKO CKS
Value Name Description
0 MCK Divided Clock
1TK TK Clock signal
2RK RK pin
3Reserved
Value Name Description TK Pin
0 NONE None Input-only
1 CONTINUOUS Continuous Receive Clock Output
2 TRANSFER Transmit Clock only during data transfers Output
3-7 Reserved
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• CKG: Transmit Clock Gating Selection
• START: Transmit Start Selection
• STTDLY: Transmit Start Delay
If STTDLY is not 0, a delay of STTDLY clock cycles is inserted between the start event and the actual start of transmission
of data. When the Transmitter is programmed to start synchronously with the Receiver, the delay is also applied.
Note: STTDLY must be set carefully. If STTDLY is too short in respect to TAG (Transmit Sync Data) emission, data is emit-
ted instead of the end of TAG.
• PERIOD: Transmit Period Divider Selection
This field selects the divider to apply to the selected Transmit Clock to generate a new Frame Sync Signal. If 0, no period
signal is generated. If not 0, a period signal is generated at each 2 x (PERIOD+1) Transmit Clock.
Value Name Description
0 NONE None
1 CONTINUOUS Transmit Clock enabled only if TF Low
2 TRANSFER Transmit Clock enabled only if TF High
Value Name Description
0CONTINUOUS
Continuous, as soon as a word is written in the SSC_THR Register (if Transmit is enabled),
and immediately after the end of transfer of the previous data.
1 RECEIVE Receive start
2RF_LOW Detection of a low level on TF signal
3 RF_HIGH Detection of a high level on TF signal
4RF_FALLING
Detection of a falling edge on TF signal
5 RF_RISING Detection of a rising edge on TF signal
6 RF_LEVEL Detection of any level change on TF signal
7RF_EDGE Detection of any edge on TF signal
8CMP_0 Compare 0
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30.9.6 SSC Transmit Frame Mode Register
Name: SSC_TFMR
Address: 0x4000401C
Access: Read-write
This register can only be written if the WPEN bit is cleared in “SSC Write Protect Mode Register” .
• DATLEN: Data Length
0 = Forbidden value (1-bit data length not supported).
Any other value: The bit stream contains DATLEN + 1 data bits. .
• DATDEF: Data Default Value
This bit defines the level driven on the TD pin while out of transmission. Note that if the pin is defined as multi-drive by the
PIO Controller, the pin is enabled only if the SCC TD output is 1.
• MSBF: Most Significant Bit First
0 = The lowest significant bit of the data register is shifted out first in the bit stream.
1 = The most significant bit of the data register is shifted out first in the bit stream.
• DATNB: Data Number per frame
This field defines the number of data words to be transferred after each transfer start, which is equal to (DATNB +1).
• FSLEN: Transmit Frame Sync Length
This field defines the length of the Transmit Frame Sync signal and the number of bits shifted out from the Transmit Sync
Data Register if FSDEN is 1.
This field is used with FSLEN_EXT to determine the pulse length of the Transmit Frame Sync signal.
Pulse length is equal to FSLEN + (FSLEN_EXT * 16) + 1 Transmit Clock period.
31 30 29 28 27 26 25 24
FSLEN_EXT FSLEN_EXT FSLEN_EXT FSLEN_EXT –––FSEDGE
23 22 21 20 19 18 17 16
FSDEN FSOS FSLEN
15 14 13 12 11 10 9 8
––– – DATNB
765 4 3210
MSBF – DATDEF DATLEN
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• FSOS: Transmit Frame Sync Output Selection
• FSDEN: Frame Sync Data Enable
0 = The TD line is driven with the default value during the Transmit Frame Sync signal.
1 = SSC_TSHR value is shifted out during the transmission of the Transmit Frame Sync signal.
• FSEDGE: Frame Sync Edge Detection
Determines which edge on frame sync will generate the interrupt TXSYN (Status Register).
• FSLEN_EXT: FSLEN Field Extension
Extends FSLEN field. For details, refer to FSLEN bit description on page 600.
Value Name Description RF Pin
0 NONE None Input-only
1NEGATIVE Negative Pulse Output
2 POSITIVE Positive Pulse Output
3LOW Driven Low during data transfer Output
4 HIGH Driven High during data transfer Output
5 TOGGLING Toggling at each start of data transfer Output
6-7 Reserved Undefined
Value Name Description
0 POSITIVE Positive Edge Detection
1NEGATIVE Negative Edge Detection
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30.9.7 SSC Receive Holding Register
Name: SSC_RHR
Address: 0x40004020
Access: Read-only
• RDAT: Receive Data
Right aligned regardless of the number of data bits defined by DATLEN in SSC_RFMR.
31 30 29 28 27 26 25 24
RDAT
23 22 21 20 19 18 17 16
RDAT
15 14 13 12 11 10 9 8
RDAT
76543210
RDAT
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30.9.8 SSC Transmit Holding Register
Name: SSC_THR
Address: 0x40004024
Access: Write-only
• TDAT: Transmit Data
Right aligned regardless of the number of data bits defined by DATLEN in SSC_TFMR.
31 30 29 28 27 26 25 24
TDAT
23 22 21 20 19 18 17 16
TDAT
15 14 13 12 11 10 9 8
TDAT
76543210
TDAT
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30.9.9 SSC Receive Synchronization Holding Register
Name: SSC_RSHR
Address: 0x40004030
Access: Read-only
• RSDAT: Receive Synchronization Data
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
RSDAT
76543210
RSDAT
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30.9.10 SSC Transmit Synchronization Holding Register
Name: SSC_TSHR
Address: 0x40004034
Access: Read-write
• TSDAT: Transmit Synchronization Data
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TSDAT
76543210
TSDAT
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30.9.11 SSC Receive Compare 0 Register
Name: SSC_RC0R
Address: 0x40004038
Access: Read-write
This register can only be written if the WPEN bit is cleared in “SSC Write Protect Mode Register” .
• CP0: Receive Compare Data 0
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CP0
76543210
CP0
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30.9.12 SSC Receive Compare 1 Register
Name: SSC_RC1R
Address: 0x4000403C
Access: Read-write
This register can only be written if the WPEN bit is cleared in “SSC Write Protect Mode Register” .
• CP1: Receive Compare Data 1
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CP1
76543210
CP1
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30.9.13 SSC Status Register
Name: SSC_SR
Address: 0x40004040
Access: Read-only
• TXRDY: Transmit Ready
0 = Data has been loaded in SSC_THR and is waiting to be loaded in the Transmit Shift Register (TSR).
1 = SSC_THR is empty.
• TXEMPTY: Transmit Empty
0 = Data remains in SSC_THR or is currently transmitted from TSR.
1 = Last data written in SSC_THR has been loaded in TSR and last data loaded in TSR has been transmitted.
• RXRDY: Receive Ready
0 = SSC_RHR is empty.
1 = Data has been received and loaded in SSC_RHR.
• OVRUN: Receive Overrun
0 = No data has been loaded in SSC_RHR while previous data has not been read since the last read of the Status
Register.
1 = Data has been loaded in SSC_RHR while previous data has not yet been read since the last read of the Status
Register.
•CP0: Compare 0
0 = A compare 0 has not occurred since the last read of the Status Register.
1 = A compare 0 has occurred since the last read of the Status Register.
•CP1: Compare 1
0 = A compare 1 has not occurred since the last read of the Status Register.
1 = A compare 1 has occurred since the last read of the Status Register.
• TXSYN: Transmit Sync
0 = A Tx Sync has not occurred since the last read of the Status Register.
1 = A Tx Sync has occurred since the last read of the Status Register.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––RXENTXEN
15 14 13 12 11 10 9 8
––––RXSYN TXSYN CP1 CP0
76543210
– – OVRUN RXRDY – – TXEMPTY TXRDY
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• RXSYN: Receive Sync
0 = An Rx Sync has not occurred since the last read of the Status Register.
1 = An Rx Sync has occurred since the last read of the Status Register.
• TXEN: Transmit Enable
0 = Transmit is disabled.
1 = Transmit is enabled.
• RXEN: Receive Enable
0 = Receive is disabled.
1 = Receive is enabled.
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30.9.14 SSC Interrupt Enable Register
Name: SSC_IER
Address: 0x40004044
Access: Write-only
• TXRDY: Transmit Ready Interrupt Enable
0 = 0 = No effect.
1 = Enables the Transmit Ready Interrupt.
• TXEMPTY: Transmit Empty Interrupt Enable
0 = No effect.
1 = Enables the Transmit Empty Interrupt.
• RXRDY: Receive Ready Interrupt Enable
0 = No effect.
1 = Enables the Receive Ready Interrupt.
• OVRUN: Receive Overrun Interrupt Enable
0 = No effect.
1 = Enables the Receive Overrun Interrupt.
• CP0: Compare 0 Interrupt Enable
0 = No effect.
1 = Enables the Compare 0 Interrupt.
• CP1: Compare 1 Interrupt Enable
0 = No effect.
1 = Enables the Compare 1 Interrupt.
• TXSYN: Tx Sync Interrupt Enable
0 = No effect.
1 = Enables the Tx Sync Interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––RXSYN TXSYN CP1 CP0
76543210
– – OVRUN RXRDY – – TXEMPTY TXRDY
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• RXSYN: Rx Sync Interrupt Enable
0 = No effect.
1 = Enables the Rx Sync Interrupt.
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30.9.15 SSC Interrupt Disable Register
Name: SSC_IDR
Address: 0x40004048
Access: Write-only
• TXRDY: Transmit Ready Interrupt Disable
0 = No effect.
1 = Disables the Transmit Ready Interrupt.
• TXEMPTY: Transmit Empty Interrupt Disable
0 = No effect.
1 = Disables the Transmit Empty Interrupt.
• RXRDY: Receive Ready Interrupt Disable
0 = No effect.
1 = Disables the Receive Ready Interrupt.
• OVRUN: Receive Overrun Interrupt Disable
0 = No effect.
1 = Disables the Receive Overrun Interrupt.
• CP0: Compare 0 Interrupt Disable
0 = No effect.
1 = Disables the Compare 0 Interrupt.
• CP1: Compare 1 Interrupt Disable
0 = No effect.
1 = Disables the Compare 1 Interrupt.
• TXSYN: Tx Sync Interrupt Enable
0 = No effect.
1 = Disables the Tx Sync Interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––RXSYN TXSYN CP1 CP0
76543210
– – OVRUN RXRDY – – TXEMPTY TXRDY
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• RXSYN: Rx Sync Interrupt Enable
0 = No effect.
1 = Disables the Rx Sync Interrupt.
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30.9.16 SSC Interrupt Mask Register
Name: SSC_IMR
Address: 0x4000404C
Access: Read-only
• TXRDY: Transmit Ready Interrupt Mask
0 = The Transmit Ready Interrupt is disabled.
1 = The Transmit Ready Interrupt is enabled.
• TXEMPTY: Transmit Empty Interrupt Mask
0 = The Transmit Empty Interrupt is disabled.
1 = The Transmit Empty Interrupt is enabled.
• RXRDY: Receive Ready Interrupt Mask
0 = The Receive Ready Interrupt is disabled.
1 = The Receive Ready Interrupt is enabled.
• OVRUN: Receive Overrun Interrupt Mask
0 = The Receive Overrun Interrupt is disabled.
1 = The Receive Overrun Interrupt is enabled.
• CP0: Compare 0 Interrupt Mask
0 = The Compare 0 Interrupt is disabled.
1 = The Compare 0 Interrupt is enabled.
• CP1: Compare 1 Interrupt Mask
0 = The Compare 1 Interrupt is disabled.
1 = The Compare 1 Interrupt is enabled.
• TXSYN: Tx Sync Interrupt Mask
0 = The Tx Sync Interrupt is disabled.
1 = The Tx Sync Interrupt is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––RXSYN TXSYN CP1 CP0
76543210
– – OVRUN RXRDY – – TXEMPTY TXRDY
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• RXSYN: Rx Sync Interrupt Mask
0 = The Rx Sync Interrupt is disabled.
1 = The Rx Sync Interrupt is enabled.
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30.9.17 SSC Write Protect Mode Register
Name: SSC_WPMR
Address: 0x400040E4
Access: Read-write
Reset: See Table 30-6
• WPEN: Write Protect Enable
0 = Disables the Write Protect if WPKEY corresponds to 0x535343 (“SSC” in ASCII).
1 = Enables the Write Protect if WPKEY corresponds to 0x535343 (“SSC” in ASCII).
Protects the registers:
•“SSC Clock Mode Register” on page 593
•“SSC Receive Clock Mode Register” on page 594
•“SSC Receive Frame Mode Register” on page 596
•“SSC Transmit Clock Mode Register” on page 598
•“SSC Transmit Frame Mode Register” on page 600
•“SSC Receive Compare 0 Register” on page 606
•“SSC Receive Compare 1 Register” on page 607
• WPKEY: Write Protect KEY
Should be written at value 0x535343 (“SSC” in ASCII). Writing any other value in this field aborts the write operation of the
WPEN bit. Always reads as 0.
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
———————WPEN
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30.9.18 SSC Write Protect Status Register
Name: SSC_WPSR
Address: 0x400040E8
Access: Read-only
Reset: See Table 30-6
• WPVS: Write Protect Violation Status
0 = No Write Protect Violation has occurred since the last read of the SSC_WPSR register.
1 = A Write Protect Violation has occurred since the last read of the SSC_WPSR register. If this violation is an unauthor-
ized attempt to write a protected register, the associated violation is reported into field WPVSRC.
• WPVSRC: Write Protect Violation Source
When WPVS is active, this field indicates the write-protected register (through address offset or code) in which a write
access has been attempted.
Note: Reading SSC_WPSR automatically clears all fields.
31 30 29 28 27 26 25 24
————————
23 22 21 20 19 18 17 16
WPVSRC
15 14 13 12 11 10 9 8
WPVSRC
76543210
———————WPVS
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31. Parallel Input/Output Controller (PIO)
31.1 Description
The Parallel Input/Output Controller (PIO) manages up to 32 fully programmable input/output lines. Each I/O line
may be dedicated as a general-purpose I/O or be assigned to a function of an embedded peripheral. This assures
effective optimization of the pins of a product.
Each I/O line is associated with a bit number in all of the 32-bit registers of the 32-bit wide User Interface.
Each I/O line of the PIO Controller features:
An input change interrupt enabling level change detection on any I/O line.
Additional Interrupt modes enabling rising edge, falling edge, low level or high level detection on any I/O line.
A glitch filter providing rejection of glitches lower than one-half of system clock cycle.
A debouncing filter providing rejection of unwanted pulses from key or push button operations.
Multi-drive capability similar to an open drain I/O line.
Control of the pull-up of the I/O line.
Input visibility and output control.
The PIO Controller also features a synchronous output providing up to 32 bits of data output in a single write
operation.
31.2 Embedded Characteristics
Up to 4 PIO Controllers, PIOA, PIOB, PIOC, PIOD, PIOE and PIOF controlling a maximum of 103 I/O Lines
Each PIO Controller controls up to 32 programmable I/O Lines
Note: 1.This device is not commercially available. Mounted only on the SAM3X-EK evaluation kit.
Fully programmable through Set/Clear Registers
Multiplexing of four peripheral functions per I/O Line
For each I/O Line (whether assigned to a peripheral or used as general purpose I/O)
̶Input change, rising edge, falling edge, low level and level interrupt
̶Debouncing and Glitch filter
̶Multi-drive option enables driving in open drain
̶Programmable pull-up on each I/O line
̶Pin data status register, supplies visibility of the level on the pin at any time
Synchronous output, provides Set and Clear of several I/O lines in a single write
Table 31-1. PIO Lines per PIO according to Version
Version
100 pin
SAM3X/A
144 pin
SAM3X
217 pin
SAM3X8H(1)
PIOA 30 32
PIOB 32
PIOC 1 31
PIOD - 10 31
PIOE - - 32
PIOF - - 6
Total 63 103 164
M $ AAAAA
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31.3 Block Diagram
Figure 31-1. Block Diagram
Figure 31-2. Application Block Diagram
Embedded
Peripheral
Embedded
Peripheral
PIO Interrupt
PIO Controller
Up to 32 pins
PMC
Up to 32
peripheral IOs
Up to 32
peripheral IOs
PIO Clock
APB
NVIC
Data, Enable
PIN 31
PIN 1
PIN 0
Data, Enable
On-Chip Peripherals
PIO Controller
On-Chip Peripheral Drivers
Control & Command
Driver
Keyboard Driver
Keyboard Driver General Purpose I/OsExternal Devices
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31.4 Product Dependencies
31.4.1 Pin Multiplexing
Each pin is configurable, according to product definition as either a general-purpose I/O line only, or as an I/O line
multiplexed with one or two peripheral I/Os. As the multiplexing is hardware defined and thus product-dependent,
the hardware designer and programmer must carefully determine the configuration of the PIO controllers required
by their application. When an I/O line is general-purpose only, i.e. not multiplexed with any peripheral I/O,
programming of the PIO Controller regarding the assignment to a peripheral has no effect and only the PIO
Controller can control how the pin is driven by the product.
31.4.2 Power Management
The Power Management Controller controls the PIO Controller clock in order to save power. Writing any of the
registers of the user interface does not require the PIO Controller clock to be enabled. This means that the
configuration of the I/O lines does not require the PIO Controller clock to be enabled.
However, when the clock is disabled, not all of the features of the PIO Controller are available, including glitch
filtering. Note that the Input Change Interrupt, Interrupt Modes on a programmable event and the read of the pin
level require the clock to be validated.
After a hardware reset, the PIO clock is disabled by default.
The user must configure the Power Management Controller before any access to the input line information.
31.4.3 Interrupt Generation
The PIO COntroller is connected on one of the sources of the Nested Vectored Interrupt Controller (NVIC). Using
the PIO Controller requires the NVIC to be programmed first.
The PIO Controller interrupt can be generated only if the PIO Controller clock is enabled.
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31.5 Functional Description
The PIO Controller features up to 32 fully-programmable I/O lines. Most of the control logic associated to each I/O
is represented in Figure 31-3. In this description each signal shown represents but one of up to 32 possible
indexes.
Figure 31-3. I/O Line Control Logic
1
0
1
0
1
0
1
0
DQ DQ
DFF
1
0
1
0
1
0
1
0
Programmable
Glitch
or
Debouncing
Filter
Peripheral A
Input
PIO_PDSR[0] PIO_ISR[0]
PIO_IDR[0]
PIO_IMR[0]
PIO_IER[0]
PIO Interrupt
(Up to 32 possible inputs)
PIO_ISR[31]
PIO_IDR[31]
PIO_IMR[31]
PIO_IER[31]
Pad
PIO_PUDR[0]
PIO_PUSR[0]
PIO_PUER[0]
PIO_MDDR[0]
PIO_MDSR[0]
PIO_MDER[0]
PIO_CODR[0]
PIO_ODSR[0]
PIO_SODR[0]
PIO_PDR[0]
PIO_PSR[0]
PIO_PER[0]
PIO_ABSR[0]
PIO_ODR[0]
PIO_OSR[0]
PIO_OER[0]
Resynchronization
Stage
Peripheral B
Input
Peripheral B
Output Enable
Peripheral A
Output Enable
Peripheral B
Output
Peripheral A
Output
EVENT
DETECTOR
DFF
PIO_IFDR[0]
PIO_IFSR[0]
PIO_IFER[0]
System Clock
Clock
Divider
PIO_IFSCR[0]
PIO_DCIFSR[0]
PIO_SCIFSR[0]
PIO_SCDR
Slow Clock
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31.5.1 Pull-up Resistor Control
Each I/O line is designed with an embedded pull-up resistor. The pull-up resistor can be enabled or disabled by
writing respectively PIO_PUER (Pull-up Enable Register) and PIO_PUDR (Pull-up Disable Resistor). Writing in
these registers results in setting or clearing the corresponding bit in PIO_PUSR (Pull-up Status Register). Reading
a 1 in PIO_PUSR means the pull-up is disabled and reading a 0 means the pull-up is enabled.
Control of the pull-up resistor is possible regardless of the configuration of the I/O line.
After reset, all of the pull-ups are enabled, i.e. PIO_PUSR resets at the value 0x0.
31.5.2 I/O Line or Peripheral Function Selection
When a pin is multiplexed with one or two peripheral functions, the selection is controlled with the registers
PIO_PER (PIO Enable Register) and PIO_PDR (PIO Disable Register). The register PIO_PSR (PIO Status
Register) is the result of the set and clear registers and indicates whether the pin is controlled by the
corresponding peripheral or by the PIO Controller. A value of 0 indicates that the pin is controlled by the
corresponding on-chip peripheral selected in the PIO_ABSR (AB Select Register). A value of 1 indicates the pin is
controlled by the PIO controller.
If a pin is used as a general purpose I/O line (not multiplexed with an on-chip peripheral), PIO_PER and PIO_PDR
have no effect and PIO_PSR returns 1 for the corresponding bit.
After reset, most generally, the I/O lines are controlled by the PIO controller, i.e. PIO_PSR resets at 1. However, in
some events, it is important that PIO lines are controlled by the peripheral (as in the case of memory chip select
lines that must be driven inactive after reset or for address lines that must be driven low for booting out of an
external memory). Thus, the reset value of PIO_PSR is defined at the product level, depending on the multiplexing
of the device.
31.5.3 Peripheral A or B Selection
The PIO Controller provides multiplexing of up to two peripheral functions on a single pin. The selection is
performed by writing PIO_ABSR (AB Select Register). For each pin, the corresponding bit at level 0 means
peripheral A is selected whereas the corresponding bit at level 1 indicates that peripheral B is selected.
Note that multiplexing of peripheral lines A and B only affects the output line. The peripheral input lines are always
connected to the pin input.
After reset, PIO_ABSR is 0, thus indicating that all the PIO lines are configured on peripheral A. However,
peripheral A generally does not drive the pin as the PIO Controller resets in I/O line mode.
Writing in PIO_ABSR manages the multiplexing regardless of the configuration of the pin. However, assignment of
a pin to a peripheral function requires a write in the peripheral selection register (PIO_ABSR) in addition to a write
in PIO_PDR.
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31.5.4 Output Control
When the I/0 line is assigned to a peripheral function, i.e. the corresponding bit in PIO_PSR is at 0, the drive of the
I/O line is controlled by the peripheral. Peripheral A or B depending on the value in PIO_ABSR (AB Select
Register) determines whether the pin is driven or not.
When the I/O line is controlled by the PIO controller, the pin can be configured to be driven. This is done by writing
PIO_OER (Output Enable Register) and PIO_ODR (Output Disable Register). The results of these write
operations are detected in PIO_OSR (Output Status Register). When a bit in this register is at 0, the corresponding
I/O line is used as an input only. When the bit is at 1, the corresponding I/O line is driven by the PIO controller.
The level driven on an I/O line can be determined by writing in PIO_SODR (Set Output Data Register) and
PIO_CODR (Clear Output Data Register). These write operations respectively set and clear PIO_ODSR (Output
Data Status Register), which represents the data driven on the I/O lines. Writing in PIO_OER and PIO_ODR
manages PIO_OSR whether the pin is configured to be controlled by the PIO controller or assigned to a peripheral
function. This enables configuration of the I/O line prior to setting it to be managed by the PIO Controller.
Similarly, writing in PIO_SODR and PIO_CODR effects PIO_ODSR. This is important as it defines the first level
driven on the I/O line.
31.5.5 Synchronous Data Output
Clearing one (or more) PIO line(s) and setting another one (or more) PIO line(s) synchronously cannot be done by
using PIO_SODR and PIO_CODR registers. It requires two successive write operations into two different
registers. To overcome this, the PIO Controller offers a direct control of PIO outputs by single write access to
PIO_ODSR (Output Data Status Register).Only bits unmasked by PIO_OWSR (Output Write Status Register) are
written. The mask bits in PIO_OWSR are set by writing to PIO_OWER (Output Write Enable Register) and cleared
by writing to PIO_OWDR (Output Write Disable Register).
After reset, the synchronous data output is disabled on all the I/O lines as PIO_OWSR resets at 0x0.
31.5.6 Multi Drive Control (Open Drain)
Each I/O can be independently programmed in Open Drain by using the Multi Drive feature. This feature permits
several drivers to be connected on the I/O line which is driven low only by each device. An external pull-up resistor
(or enabling of the internal one) is generally required to guarantee a high level on the line.
The Multi Drive feature is controlled by PIO_MDER (Multi-driver Enable Register) and PIO_MDDR (Multi-driver
Disable Register). The Multi Drive can be selected whether the I/O line is controlled by the PIO controller or
assigned to a peripheral function. PIO_MDSR (Multi-driver Status Register) indicates the pins that are configured
to support external drivers.
After reset, the Multi Drive feature is disabled on all pins, i.e. PIO_MDSR resets at value 0x0.
31.5.7 Output Line Timings
Figure 31-4 shows how the outputs are driven either by writing PIO_SODR or PIO_CODR, or by directly writing
PIO_ODSR. This last case is valid only if the corresponding bit in PIO_OWSR is set. Figure 31-4 also shows when
the feedback in PIO_PDSR is available.
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Figure 31-4. Output Line Timings
31.5.8 Inputs
The level on each I/O line can be read through PIO_PDSR (Pin Data Status Register). This register indicates the
level of the I/O lines regardless of their configuration, whether uniquely as an input or driven by the PIO controller
or driven by a peripheral.
Reading the I/O line levels requires the clock of the PIO controller to be enabled, otherwise PIO_PDSR reads the
levels present on the I/O line at the time the clock was disabled.
31.5.9 Input Glitch and Debouncing Filters
Optional input glitch and debouncing filters are independently programmable on each I/O line.
The glitch filter can filter a glitch with a duration of less than 1/2 Master Clock (MCK) and the debouncing filter can
filter a pulse of less than 1/2 Period of a Programmable Divided Slow Clock.
The selection between glitch filtering or debounce filtering is done by writing in the registers PIO_SCIFSR (System
Clock Glitch Input Filter Select Register) and PIO_DIFSR (Debouncing Input Filter Select Register). Writing
PIO_SCIFSR and PIO_DIFSR respectively, sets and clears bits in PIO_IFDGSR.
The current selection status can be checked by reading the register PIO_IFDGSR (Glitch or Debouncing Input
Filter Selection Status Register).
If PIO_IFDGSR[i] = 0: The glitch filter can filter a glitch with a duration of less than 1/2 Period of Master
Clock.
If PIO_IFDGSR[i] = 1: The debouncing filter can filter a pulse with a duration of less than 1/2 Period of the
Programmable Divided Slow Clock.
For the debouncing filter, the Period of the Divided Slow Clock is performed by writing in the DIV field of the
PIO_SCDR (Slow Clock Divider Register)
Tdiv_slclk = ((DIV+1)*2).Tslow_clock
When the glitch or debouncing filter is enabled, a glitch or pulse with a duration of less than 1/2 Selected Clock
Cycle (Selected Clock represents MCK or Divided Slow Clock depending on PIO_SCIFSR and PIO_DIFSR
programming) is automatically rejected, while a pulse with a duration of 1 Selected Clock (MCK or Divided Slow
Clock) cycle or more is accepted. For pulse durations between 1/2 Selected Clock cycle and 1 Selected Clock
cycle the pulse may or may not be taken into account, depending on the precise timing of its occurrence. Thus for
a pulse to be visible it must exceed 1 Selected Clock cycle, whereas for a glitch to be reliably filtered out, its
duration must not exceed 1/2 Selected Clock cycle.
The filters also introduce some latencies, this is illustrated in Figure 31-5 and Figure 31-6.
2 cycles
APB Access
2 cycles
APB Access
MCK
Write PIO_SODR
Write PIO_ODSR at 1
PIO_ODSR
PIO_PDSR
Write PIO_CODR
Write PIO_ODSR at 0
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The glitch filters are controlled by the register set: PIO_IFER (Input Filter Enable Register), PIO_IFDR (Input Filter
Disable Register) and PIO_IFSR (Input Filter Status Register). Writing PIO_IFER and PIO_IFDR respectively sets
and clears bits in PIO_IFSR. This last register enables the glitch filter on the I/O lines.
When the glitch and/or debouncing filter is enabled, it does not modify the behavior of the inputs on the
peripherals. It acts only on the value read in PIO_PDSR and on the input change interrupt detection. The glitch and
debouncing filters require that the PIO Controller clock is enabled.
Figure 31-5. Input Glitch Filter Timing
Figure 31-6. Input Debouncing Filter Timing
31.5.10 Input Edge/Level Interrupt
The PIO Controller can be programmed to generate an interrupt when it detects an edge or a level on an I/O line.
The Input Edge/Level Interrupt is controlled by writing PIO_IER (Interrupt Enable Register) and PIO_IDR (Interrupt
Disable Register), which respectively enable and disable the input change interrupt by setting and clearing the
corresponding bit in PIO_IMR (Interrupt Mask Register). As Input change detection is possible only by comparing
two successive samplings of the input of the I/O line, the PIO Controller clock must be enabled. The Input Change
Interrupt is available, regardless of the configuration of the I/O line, i.e. configured as an input only, controlled by
the PIO Controller or assigned to a peripheral function.
By default, the interrupt can be generated at any time an edge is detected on the input.
Some additional Interrupt modes can be enabled/disabled by writing in the PIO_AIMER (Additional Interrupt
Modes Enable Register) and PIO_AIMDR (Additional Interrupt Modes Disable Register). The current state of this
selection can be read through the PIO_AIMMR (Additional Interrupt Modes Mask Register)
MCK
Pin Level
PIO_PDSR
if PIO_IFSR = 0
PIO_PDSR
if PIO_IFSR = 1
1 cycle 1 cycle 1 cycle
up to 1.5 cycles
2 cycles
up to 2.5 cycles
up to 2 cycles
1 cycle
1 cycle
PIO_IFCSR = 0
Divided Slow Clock
Pin Level
PIO_PDSR
if PIO_IFSR = 0
PIO_PDSR
if PIO_IFSR = 1
1 cycle Tdiv_slclk
up to 1.5 cycles Tdiv_slclk
1 cycle Tdiv_slclk
up to 2 cycles Tmck up to 2 cycles Tmck
up to 2 cycles Tmck
up to 2 cycles Tmck
up to 1.5 cycles Tdiv_slclk
PIO_IFCSR = 1
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These Additional Modes are:
Rising Edge Detection
Falling Edge Detection
Low Level Detection
High Level Detection
In order to select an Additional Interrupt Mode:
The type of event detection (Edge or Level) must be selected by writing in the set of registers; PIO_ESR
(Edge Select Register) and PIO_LSR (Level Select Register) which enable respectively, the Edge and Level
Detection. The current status of this selection is accessible through the PIO_ELSR (Edge/Level Status
Register).
The Polarity of the event detection (Rising/Falling Edge or High/Low Level) must be selected by writing in
the set of registers; PIO_FELLSR (Falling Edge /Low Level Select Register) and PIO_REHLSR (Rising
Edge/High Level Select Register) which allow to select Falling or Rising Edge (if Edge is selected in the
PIO_ELSR) Edge or High or Low Level Detection (if Level is selected in the PIO_ELSR). The current status
of this selection is accessible through the PIO_FRLHSR (Fall/Rise - Low/High Status Register).
When an input Edge or Level is detected on an I/O line, the corresponding bit in PIO_ISR (Interrupt Status
Register) is set. If the corresponding bit in PIO_IMR is set, the PIO Controller interrupt line is asserted. The
interrupt signals of the thirty-two channels are ORed-wired together to generate a single interrupt signal to the
Nested Vector Interrupt Controller (NVIC).
When the software reads PIO_ISR, all the interrupts are automatically cleared. This signifies that all the interrupts
that are pending when PIO_ISR is read must be handled. When an Interrupt is enabled on a “Level”, the interrupt
is generated as long as the interrupt source is not cleared, even if some read accesses in PIO_ISR are performed.
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Figure 31-7. Event Detector on Input Lines (Figure represents line 0)
31.5.10.1 Example
If generating an interrupt is required on the following:
Rising edge on PIO line 0
Falling edge on PIO line 1
Rising edge on PIO line 2
Low Level on PIO line 3
High Level on PIO line 4
High Level on PIO line 5
Falling edge on PIO line 6
Rising edge on PIO line 7
Any edge on the other lines
The configuration required is described below.
31.5.10.2 Interrupt Mode Configuration
All the interrupt sources are enabled by writing 32’hFFFF_FFFF in PIO_IER.
Then the Additional Interrupt Mode is enabled for line 0 to 7 by writing 32’h0000_00FF in PIO_AIMER.
31.5.10.3 Edge or Level Detection Configuration
Lines 3, 4 and 5 are configured in Level detection by writing 32’h0000_0038 in PIO_LSR.
The other lines are configured in Edge detection by default, if they have not been previously configured.
Otherwise, lines 0, 1, 2, 6 and 7 must be configured in Edge detection by writing 32’h0000_00C7 in PIO_ESR.
31.5.10.4 Falling/Rising Edge or Low/High Level Detection Configuration.
Lines 0, 2, 4, 5 and 7 are configured in Rising Edge or High Level detection by writing 32’h0000_00B5 in
PIO_REHLSR.
The other lines are configured in Falling Edge or Low Level detection by default, if they have not been previously
configured. Otherwise, lines 1, 3 and 6 must be configured in Falling Edge/Low Level detection by writing
32’h0000_004A in PIO_FELLSR.
Event Detector
0
1
0
1
1
0
0
1
Edge
Detector
Falling Edge
Detector
Rising Edge
Detector
PIO_FELLSR[0]
PIO_FRLHSR[0]
PIO_REHLSR[0]
Low Level
Detector
High Level
Detector
PIO_ESR[0]
PIO_ELSR[0]
PIO_LSR[0]
PIO_AIMDR[0]
PIO_AIMMR[0]
PIO_AIMER[0]
Event detection on line 0
Resynchronized input on line 0
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Figure 31-8. Input Change Interrupt Timings if there are no Additional Interrupt Modes
31.5.11 I/O Lines Lock
When an I/O line is controlled by a peripheral (particularly the Pulse Width Modulation Controller PWM), it can
become locked by the action of this peripheral via an input of the PIO controller. When an I/O line is locked, the
write of the corresponding bit in the registers PIO_PER, PIO_PDR, PIO_MDER, PIO_MDDR, PIO_PUDR,
PIO_PUER and PIO_ABSR is discarded in order to lock its configuration. The user can know at anytime which I/O
line is locked by reading the PIO Lock Status register PIO_LOCKSR. Once an I/O line is locked, the only way to
unlock it is to apply an hardware reset to the PIO Controller.
MCK
Pin Level
Read PIO_ISRAPB Access
PIO_ISR
APB Access
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31.6 I/O Lines Programming Example
The programing example as shown in Table 31-2 below is used to obtain the following configuration.
4-bit output port on I/O lines 0 to 3, (should be written in a single write operation), open-drain, with pull-up
resistor
Four output signals on I/O lines 4 to 7 (to drive LEDs for example), driven high and low, no pull-up resistor
Four input signals on I/O lines 8 to 11 (to read push-button states for example), with pull-up resistors, glitch
filters and input change interrupts
Four input signals on I/O line 12 to 15 to read an external device status (polled, thus no input change
interrupt), no pull-up resistor, no glitch filter
I/O lines 16 to 19 assigned to peripheral A functions with pull-up resistor
I/O lines 20 to 23 assigned to peripheral B functions, no pull-up resistor
I/O line 24 to 27 assigned to peripheral A with Input Change Interrupt and pull-up resistor
Table 31-2. Programming Example
Register Value to be Written
PIO_PER 0x0000 FFFF
PIO_PDR 0xFFFF 0000
PIO_OER 0x0000 00FF
PIO_ODR 0xFFFF FF00
PIO_IFER 0x0000 0F00
PIO_IFDR 0xFFFF F0FF
PIO_SODR 0x0000 0000
PIO_CODR 0x0FFF FFFF
PIO_IER 0x0F00 0F00
PIO_IDR 0xF0FF F0FF
PIO_MDER 0x0000 000F
PIO_MDDR 0xFFFF FFF0
PIO_PUDR 0xF0F0 00F0
PIO_PUER 0x0F0F FF0F
PIO_ABSR 0x00F0 0000
PIO_OWER 0x0000 000F
PIO_OWDR 0x0FFF FFF0
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31.6.1 Write Protection Registers
To prevent any single software error that may corrupt PIO behavior, certain address spaces can be write-protected
by setting the WPEN bit in the “PIO Write Protect Mode Register” (PIO_WPMR).
If a write access to the protected registers is detected, then the WPVS flag in the PIO Write Protect Status Register
(PIO_WPSR) is set and the field WPVSRC indicates in which register the write access has been attempted.
The WPVS flag is reset by writing the PIO Write Protect Mode Register (PIO_WPMR) with the appropriate access
key, WPKEY.
The protected registers are:
“PIO Controller PIO Enable Register” on page 633
“PIO Controller PIO Disable Register” on page 634
“PIO Controller Output Enable Register” on page 636
“PIO Controller Output Disable Register” on page 637
“PIO Controller Input Filter Enable Register” on page 639
“PIO Controller Input Filter Disable Register” on page 640
“PIO Multi-driver Enable Register” on page 650
“PIO Multi-driver Disable Register” on page 651
“PIO Pull Up Disable Register” on page 653
“PIO Pull Up Enable Register” on page 654
“PIO Peripheral AB Select Register” on page 656
“PIO Output Write Enable Register” on page 661
“PIO Output Write Disable Register” on page 662
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31.7 Parallel Input/Output Controller (PIO) User Interface
Each I/O line controlled by the PIO Controller is associated with a bit in each of the PIO Controller User Interface
registers. Each register is 32 bits wide. If a parallel I/O line is not defined, writing to the corresponding bits has no
effect. Undefined bits read zero. If the I/O line is not multiplexed with any peripheral, the I/O line is controlled by the
PIO Controller and PIO_PSR returns 1 systematically.
Table 31-3. Register Mapping
Offset Register Name Access Reset
0x0000 PIO Enable Register PIO_PER Write-only –
0x0004 PIO Disable Register PIO_PDR Write-only –
0x0008 PIO Status Register PIO_PSR Read-only (1)
0x000C Reserved
0x0010 Output Enable Register PIO_OER Write-only –
0x0014 Output Disable Register PIO_ODR Write-only –
0x0018 Output Status Register PIO_OSR Read-only 0x0000 0000
0x001C Reserved
0x0020 Glitch Input Filter Enable Register PIO_IFER Write-only –
0x0024 Glitch Input Filter Disable Register PIO_IFDR Write-only –
0x0028 Glitch Input Filter Status Register PIO_IFSR Read-only 0x0000 0000
0x002C Reserved
0x0030 Set Output Data Register PIO_SODR Write-only –
0x0034 Clear Output Data Register PIO_CODR Write-only
0x0038 Output Data Status Register PIO_ODSR Read-only
or(2)
Read-write –
0x003C Pin Data Status Register PIO_PDSR Read-only (3)
0x0040 Interrupt Enable Register PIO_IER Write-only –
0x0044 Interrupt Disable Register PIO_IDR Write-only –
0x0048 Interrupt Mask Register PIO_IMR Read-only 0x00000000
0x004C Interrupt Status Register(4) PIO_ISR Read-only 0x00000000
0x0050 Multi-driver Enable Register PIO_MDER Write-only –
0x0054 Multi-driver Disable Register PIO_MDDR Write-only –
0x0058 Multi-driver Status Register PIO_MDSR Read-only 0x00000000
0x005C Reserved
0x0060 Pull-up Disable Register PIO_PUDR Write-only –
0x0064 Pull-up Enable Register PIO_PUER Write-only –
0x0068 Pad Pull-up Status Register PIO_PUSR Read-only 0x00000000
0x006C Reserved
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Notes: 1. Reset value of PIO_PSR depends on the product implementation.
2. PIO_ODSR is Read-only or Read/Write depending on PIO_OWSR I/O lines.
3. Reset value of PIO_PDSR depends on the level of the I/O lines. Reading the I/O line levels requires the clock of the PIO
Controller to be enabled, otherwise PIO_PDSR reads the levels present on the I/O line at the time the clock was disabled.
4. PIO_ISR is reset at 0x0. However, the first read of the register may read a different value as input changes may have
occurred.
5. Only this set of registers clears the status by writing 1 in the first register and sets the status by writing 1 in the second
register.
0x0070 Peripheral AB Select Register(5) PIO_ABSR Read-Write 0x00000000
0x0074 to
0x007C Reserved
0x0080 System Clock Glitch Input Filter Select Register PIO_SCIFSR Write-Only –
0x0084 Debouncing Input Filter Select Register PIO_DIFSR Write-Only –
0x0088 Glitch or Debouncing Input Filter Clock Selection Status Register PIO_IFDGSR Read-Only 0x00000000
0x008C Slow Clock Divider Debouncing Register PIO_SCDR Read-Write 0x00000000
0x0090 to
0x009C Reserved
0x00A0 Output Write Enable PIO_OWER Write-only –
0x00A4 Output Write Disable PIO_OWDR Write-only –
0x00A8 Output Write Status Register PIO_OWSR Read-only 0x00000000
0x00AC Reserved
0x00B0 Additional Interrupt Modes Enable Register PIO_AIMER Write-Only –
0x00B4 Additional Interrupt Modes Disables Register PIO_AIMDR Write-Only –
0x00B8 Additional Interrupt Modes Mask Register PIO_AIMMR Read-Only 0x00000000
0x00BC Reserved
0x00C0 Edge Select Register PIO_ESR Write-Only –
0x00C4 Level Select Register PIO_LSR Write-Only –
0x00C8 Edge/Level Status Register PIO_ELSR Read-Only 0x00000000
0x00CC Reserved
0x00D0 Falling Edge/Low Level Select Register PIO_FELLSR Write-Only –
0x00D4 Rising Edge/ High Level Select Register PIO_REHLSR Write-Only –
0x00D8 Fall/Rise - Low/High Status Register PIO_FRLHSR Read-Only 0x00000000
0x00DC Reserved
0x00E0 Lock Status PIO_LOCKSR Read-Only 0x00000000
0x00E4 Write Protect Mode Register PIO_WPMR Read-write 0x0
0x00E8 Write Protect Status Register PIO_WPSR Read-only 0x0
0x00EC to
0x00F8 Reserved
0x0100 to
0x0144 Reserved
Table 31-3. Register Mapping (Continued)
Offset Register Name Access Reset
AtmeL
633
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.1 PIO Controller PIO Enable Register
Name: PIO_PER
Address: 0x400E0E00 (PIOA), 0x400E1000 (PIOB), 0x400E1200 (PIOC), 0x400E1400 (PIOD), 0x400E1600 (PIOE),
0x400E1800 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: PIO Enable
0: No effect.
1: Enables the PIO to control the corresponding pin (disables peripheral control of the pin).
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
634
31.7.2 PIO Controller PIO Disable Register
Name: PIO_PDR
Address: 0x400E0E04 (PIOA), 0x400E1004 (PIOB), 0x400E1204 (PIOC), 0x400E1404 (PIOD), 0x400E1604 (PIOE),
0x400E1804 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: PIO Disable
0: No effect.
1: Disables the PIO from controlling the corresponding pin (enables peripheral control of the pin).
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
635
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.3 PIO Controller PIO Status Register
Name: PIO_PSR
Address: 0x400E0E08 (PIOA), 0x400E1008 (PIOB), 0x400E1208 (PIOC), 0x400E1408 (PIOD), 0x400E1608 (PIOE),
0x400E1808 (PIOF)
Access: Read-only
• P0-P31: PIO Status
0: PIO is inactive on the corresponding I/O line (peripheral is active).
1: PIO is active on the corresponding I/O line (peripheral is inactive).
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
636
31.7.4 PIO Controller Output Enable Register
Name: PIO_OER
Address: 0x400E0E10 (PIOA), 0x400E1010 (PIOB), 0x400E1210 (PIOC), 0x400E1410 (PIOD), 0x400E1610 (PIOE),
0x400E1810 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Output Enable
0: No effect.
1: Enables the output on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
637
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.5 PIO Controller Output Disable Register
Name: PIO_ODR
Address: 0x400E0E14 (PIOA), 0x400E1014 (PIOB), 0x400E1214 (PIOC), 0x400E1414 (PIOD), 0x400E1614 (PIOE),
0x400E1814 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Output Disable
0: No effect.
1: Disables the output on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
638
31.7.6 PIO Controller Output Status Register
Name: PIO_OSR
Address: 0x400E0E18 (PIOA), 0x400E1018 (PIOB), 0x400E1218 (PIOC), 0x400E1418 (PIOD), 0x400E1618 (PIOE),
0x400E1818 (PIOF)
Access: Read-only
• P0-P31: Output Status
0: The I/O line is a pure input.
1: The I/O line is enabled in output.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
639
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.7 PIO Controller Input Filter Enable Register
Name: PIO_IFER
Address: 0x400E0E20 (PIOA), 0x400E1020 (PIOB), 0x400E1220 (PIOC), 0x400E1420 (PIOD), 0x400E1620 (PIOE),
0x400E1820 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Input Filter Enable
0: No effect.
1: Enables the input glitch filter on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
640
31.7.8 PIO Controller Input Filter Disable Register
Name: PIO_IFDR
Address: 0x400E0E24 (PIOA), 0x400E1024 (PIOB), 0x400E1224 (PIOC), 0x400E1424 (PIOD), 0x400E1624 (PIOE),
0x400E1824 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Input Filter Disable
0: No effect.
1: Disables the input glitch filter on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
641
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.9 PIO Controller Input Filter Status Register
Name: PIO_IFSR
Address: 0x400E0E28 (PIOA), 0x400E1028 (PIOB), 0x400E1228 (PIOC), 0x400E1428 (PIOD), 0x400E1628 (PIOE),
0x400E1828 (PIOF)
Access: Read-only
• P0-P31: Input Filer Status
0: The input glitch filter is disabled on the I/O line.
1: The input glitch filter is enabled on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
642
31.7.10 PIO Controller Set Output Data Register
Name: PIO_SODR
Address: 0x400E0E30 (PIOA), 0x400E1030 (PIOB), 0x400E1230 (PIOC), 0x400E1430 (PIOD), 0x400E1630 (PIOE),
0x400E1830 (PIOF)
Access: Write-only
• P0-P31: Set Output Data
0: No effect.
1: Sets the data to be driven on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
643
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.11 PIO Controller Clear Output Data Register
Name: PIO_CODR
Address: 0x400E0E34 (PIOA), 0x400E1034 (PIOB), 0x400E1234 (PIOC), 0x400E1434 (PIOD), 0x400E1634 (PIOE),
0x400E1834 (PIOF)
Access: Write-only
• P0-P31: Clear Output Data
0: No effect.
1: Clears the data to be driven on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
644
31.7.12 PIO Controller Output Data Status Register
Name: PIO_ODSR
Address: 0x400E0E38 (PIOA), 0x400E1038 (PIOB), 0x400E1238 (PIOC), 0x400E1438 (PIOD), 0x400E1638 (PIOE),
0x400E1838 (PIOF)
Access: Read-only or Read/Write
• P0-P31: Output Data Status
0: The data to be driven on the I/O line is 0.
1: The data to be driven on the I/O line is 1.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
645
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.13 PIO Controller Pin Data Status Register
Name: PIO_PDSR
Address: 0x400E0E3C (PIOA), 0x400E103C (PIOB), 0x400E123C (PIOC), 0x400E143C (PIOD),
0x400E163C (PIOE), 0x400E183C (PIOF)
Access: Read-only
• P0-P31: Output Data Status
0: The I/O line is at level 0.
1: The I/O line is at level 1.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
646
31.7.14 PIO Controller Interrupt Enable Register
Name: PIO_IER
Address: 0x400E0E40 (PIOA), 0x400E1040 (PIOB), 0x400E1240 (PIOC), 0x400E1440 (PIOD), 0x400E1640 (PIOE),
0x400E1840 (PIOF)
Access: Write-only
• P0-P31: Input Change Interrupt Enable
0: No effect.
1: Enables the Input Change Interrupt on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
647
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.15 PIO Controller Interrupt Disable Register
Name: PIO_IDR
Address: 0x400E0E44 (PIOA), 0x400E1044 (PIOB), 0x400E1244 (PIOC), 0x400E1444 (PIOD), 0x400E1644 (PIOE),
0x400E1844 (PIOF)
Access: Write-only
• P0-P31: Input Change Interrupt Disable
0: No effect.
1: Disables the Input Change Interrupt on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
648
31.7.16 PIO Controller Interrupt Mask Register
Name: PIO_IMR
Address: 0x400E0E48 (PIOA), 0x400E1048 (PIOB), 0x400E1248 (PIOC), 0x400E1448 (PIOD), 0x400E1648 (PIOE),
0x400E1848 (PIOF)
Access: Read-only
• P0-P31: Input Change Interrupt Mask
0: Input Change Interrupt is disabled on the I/O line.
1: Input Change Interrupt is enabled on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
649
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.17 PIO Controller Interrupt Status Register
Name: PIO_ISR
Address: 0x400E0E4C (PIOA), 0x400E104C (PIOB), 0x400E124C (PIOC), 0x400E144C (PIOD),
0x400E164C (PIOE), 0x400E184C (PIOF)
Access: Read-only
• P0-P31: Input Change Interrupt Status
0: No Input Change has been detected on the I/O line since PIO_ISR was last read or since reset.
1: At least one Input Change has been detected on the I/O line since PIO_ISR was last read or since reset.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
650
31.7.18 PIO Multi-driver Enable Register
Name: PIO_MDER
Address: 0x400E0E50 (PIOA), 0x400E1050 (PIOB), 0x400E1250 (PIOC), 0x400E1450 (PIOD), 0x400E1650 (PIOE),
0x400E1850 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Multi Drive Enable.
0: No effect.
1: Enables Multi Drive on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
651
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.19 PIO Multi-driver Disable Register
Name: PIO_MDDR
Address: 0x400E0E54 (PIOA), 0x400E1054 (PIOB), 0x400E1254 (PIOC), 0x400E1454 (PIOD), 0x400E1654 (PIOE),
0x400E1854 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Multi Drive Disable.
0: No effect.
1: Disables Multi Drive on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
652
31.7.20 PIO Multi-driver Status Register
Name: PIO_MDSR
Address: 0x400E0E58 (PIOA), 0x400E1058 (PIOB), 0x400E1258 (PIOC), 0x400E1458 (PIOD), 0x400E1658 (PIOE),
0x400E1858 (PIOF)
Access: Read-only
• P0-P31: Multi Drive Status.
0: The Multi Drive is disabled on the I/O line. The pin is driven at high and low level.
1: The Multi Drive is enabled on the I/O line. The pin is driven at low level only.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
653
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.21 PIO Pull Up Disable Register
Name: PIO_PUDR
Address: 0x400E0E60 (PIOA), 0x400E1060 (PIOB), 0x400E1260 (PIOC), 0x400E1460 (PIOD), 0x400E1660 (PIOE),
0x400E1860 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Pull Up Disable.
0: No effect.
1: Disables the pull up resistor on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
654
31.7.22 PIO Pull Up Enable Register
Name: PIO_PUER
Address: 0x400E0E64 (PIOA), 0x400E1064 (PIOB), 0x400E1264 (PIOC), 0x400E1464 (PIOD), 0x400E1664 (PIOE),
0x400E1864 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Pull Up Enable.
0: No effect.
1: Enables the pull up resistor on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
655
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.23 PIO Pull Up Status Register
Name: PIO_PUSR
Address: 0x400E0E68 (PIOA), 0x400E1068 (PIOB), 0x400E1268 (PIOC), 0x400E1468 (PIOD), 0x400E1668 (PIOE),
0x400E1868 (PIOF)
Access: Read-only
• P0-P31: Pull Up Status.
0: Pull Up resistor is enabled on the I/O line.
1: Pull Up resistor is disabled on the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
656
31.7.24 PIO Peripheral AB Select Register
Name: PIO_ABSR
Address: 0x400E0E70 (PIOA), 0x400E1070 (PIOB), 0x400E1270 (PIOC), 0x400E1470 (PIOD), 0x400E1670 (PIOE),
0x400E1870 (PIOF)
Access: Read-Write
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Peripheral A Select.
0: Assigns the I/O line to the Peripheral A function.
1: Assigns the I/O line to the Peripheral B function.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
657
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.25 PIO System Clock Glitch Input Filtering Select Register
Name: PIO_SCIFSR
Address: 0x400E0E80 (PIOA), 0x400E1080 (PIOB), 0x400E1280 (PIOC), 0x400E1480 (PIOD), 0x400E1680 (PIOE),
0x400E1880 (PIOF)
Access: Write-only
• P0-P31: System Clock Glitch Filtering Select.
0: No Effect.
1: The Glitch Filter is able to filter glitches with a duration < Tmck/2.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
658
31.7.26 PIO Debouncing Input Filtering Select Register
Name: PIO_DIFSR
Address: 0x400E0E84 (PIOA), 0x400E1084 (PIOB), 0x400E1284 (PIOC), 0x400E1484 (PIOD), 0x400E1684 (PIOE),
0x400E1884 (PIOF)
Access: Write-only
• P0-P31: Debouncing Filtering Select.
0: No Effect.
1: The Debouncing Filter is able to filter pulses with a duration < Tdiv_slclk/2.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
659
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.27 PIO Glitch or Debouncing Input Filter Selection Status Register
Name: PIO_IFDGSR
Address: 0x400E0E88 (PIOA), 0x400E1088 (PIOB), 0x400E1288 (PIOC), 0x400E1488 (PIOD), 0x400E1688 (PIOE),
0x400E1888 (PIOF)
Access: Read-only
• P0-P31: Glitch or Debouncing Filter Selection Status
0: The Glitch Filter is able to filter glitches with a duration < Tmck2.
1: The Debouncing Filter is able to filter pulses with a duration < Tdiv_slclk/2.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
660
31.7.28 PIO Slow Clock Divider Debouncing Register
Name: PIO_SCDR
Address: 0x400E0E8C (PIOA), 0x400E108C (PIOB), 0x400E128C (PIOC), 0x400E148C (PIOD),
0x400E168C (PIOE), 0x400E188C (PIOF)
Access: Read-Write
• DIV: Slow Clock Divider Selection for Debouncing
Tdiv_slclk = 2*(DIV+1)*Tslow_clock.
3130292827 26 25 24
--------
2322 21 20 19 1817 16
--------
15 14 1312 11 10 9 8
--DIV13DIV12 DIV11 DIV10 DIV9 DIV8
76543210
DIV7 DIV6 DIV5 DIV4 DIV3DIV2 DIV1 DIV0
AtmeL
661
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.29 PIO Output Write Enable Register
Name: PIO_OWER
Address: 0x400E0EA0 (PIOA), 0x400E10A0 (PIOB), 0x400E12A0 (PIOC), 0x400E14A0 (PIOD),
0x400E16A0 (PIOE), 0x400E18A0 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Output Write Enable.
0: No effect.
1: Enables writing PIO_ODSR for the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
662
31.7.30 PIO Output Write Disable Register
Name: PIO_OWDR
Address: 0x400E0EA4 (PIOA), 0x400E10A4 (PIOB), 0x400E12A4 (PIOC), 0x400E14A4 (PIOD),
0x400E16A4 (PIOE), 0x400E18A4 (PIOF)
Access: Write-only
This register can only be written if the WPEN bit is cleared in “PIO Write Protect Mode Register” .
• P0-P31: Output Write Disable.
0: No effect.
1: Disables writing PIO_ODSR for the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
663
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.31 PIO Output Write Status Register
Name: PIO_OWSR
Address: 0x400E0EA8 (PIOA), 0x400E10A8 (PIOB), 0x400E12A8 (PIOC), 0x400E14A8 (PIOD),
0x400E16A8 (PIOE), 0x400E18A8 (PIOF)
Access: Read-only
• P0-P31: Output Write Status.
0: Writing PIO_ODSR does not affect the I/O line.
1: Writing PIO_ODSR affects the I/O line.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
664
31.7.32 Additional Interrupt Modes Enable Register
Name: PIO_AIMER
Address: 0x400E0EB0 (PIOA), 0x400E10B0 (PIOB), 0x400E12B0 (PIOC), 0x400E14B0 (PIOD),
0x400E16B0 (PIOE), 0x400E18B0 (PIOF)
Access: Write-only
• P0-P31: Additional Interrupt Modes Enable.
0: No effect.
1: The interrupt source is the event described in PIO_ELSR and PIO_FRLHSR.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
665
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.33 Additional Interrupt Modes Disable Register
Name: PIO_AIMDR
Address: 0x400E0EB4 (PIOA), 0x400E10B4 (PIOB), 0x400E12B4 (PIOC), 0x400E14B4 (PIOD),
0x400E16B4 (PIOE), 0x400E18B4 (PIOF)
Access: Write-only
• P0-P31: Additional Interrupt Modes Disable.
0: No effect.
1: The interrupt mode is set to the default interrupt mode (Both Edge detection).
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
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666
31.7.34 Additional Interrupt Modes Mask Register
Name: PIO_AIMMR
Address: 0x400E0EB8 (PIOA), 0x400E10B8 (PIOB), 0x400E12B8 (PIOC), 0x400E14B8 (PIOD),
0x400E16B8 (PIOE), 0x400E18B8 (PIOF)
Access: Read-only
• P0-P31: Peripheral CD Status.
0: The interrupt source is a Both Edge detection event
1: The interrupt source is described by the registers PIO_ELSR and PIO_FRLHSR
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
667
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.35 Edge Select Register
Name: PIO_ESR
Address: 0x400E0EC0 (PIOA), 0x400E10C0 (PIOB), 0x400E12C0 (PIOC), 0x400E14C0 (PIOD),
0x400E16C0 (PIOE), 0x400E18C0 (PIOF)
Access: Write-only
• P0-P31: Edge Interrupt Selection.
0: No effect.
1: The interrupt source is an Edge detection event.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
668
31.7.36 Level Select Register
Name: PIO_LSR
Address: 0x400E0EC4 (PIOA), 0x400E10C4 (PIOB), 0x400E12C4 (PIOC), 0x400E14C4 (PIOD),
0x400E16C4 (PIOE), 0x400E18C4 (PIOF)
Access: Write-only
• P0-P31: Level Interrupt Selection.
0: No effect.
1: The interrupt source is a Level detection event.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
669
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.37 Edge/Level Status Register
Name: PIO_ELSR
Address: 0x400E0EC8 (PIOA), 0x400E10C8 (PIOB), 0x400E12C8 (PIOC), 0x400E14C8 (PIOD),
0x400E16C8 (PIOE), 0x400E18C8 (PIOF)
Access: Read-only
• P0-P31: Edge/Level Interrupt source selection.
0: The interrupt source is an Edge detection event.
1: The interrupt source is a Level detection event.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
670
31.7.38 Falling Edge/Low Level Select Register
Name: PIO_FELLSR
Address: 0x400E0ED0 (PIOA), 0x400E10D0 (PIOB), 0x400E12D0 (PIOC), 0x400E14D0 (PIOD),
0x400E16D0 (PIOE), 0x400E18D0 (PIOF)
Access: Write-only
• P0-P31: Falling Edge/Low Level Interrupt Selection.
0: No effect.
1: The interrupt source is set to a Falling Edge detection or Low Level detection event, depending on PIO_ELSR.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
671
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.39 Rising Edge/High Level Select Register
Name: PIO_REHLSR
Address: 0x400E0ED4 (PIOA), 0x400E10D4 (PIOB), 0x400E12D4 (PIOC), 0x400E14D4 (PIOD),
0x400E16D4 (PIOE), 0x400E18D4 (PIOF)
Access: Write-only
• P0-P31: Rising Edge /High Level Interrupt Selection.
0: No effect.
1: The interrupt source is set to a Rising Edge detection or High Level detection event, depending on PIO_ELSR.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
672
31.7.40 Fall/Rise - Low/High Status Register
Name: PIO_FRLHSR
Address: 0x400E0ED8 (PIOA), 0x400E10D8 (PIOB), 0x400E12D8 (PIOC), 0x400E14D8 (PIOD),
0x400E16D8 (PIOE), 0x400E18D8 (PIOF)
Access: Read-only
• P0-P31: Edge /Level Interrupt Source Selection.
0: The interrupt source is a Falling Edge detection (if PIO_ELSR = 0) or Low Level detection event (if PIO_ELSR = 1).
1: The interrupt source is a Rising Edge detection (if PIO_ELSR = 0) or High Level detection event (if PIO_ELSR = 1).
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
673
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
31.7.41 Lock Status Register
Name: PIO_LOCKSR
Address: 0x400E0EE0 (PIOA), 0x400E10E0 (PIOB), 0x400E12E0 (PIOC), 0x400E14E0 (PIOD),
0x400E16E0 (PIOE), 0x400E18E0 (PIOF)
Access: Read-only
• P0-P31: Lock Status.
0: The I/O line is not locked.
1: The I/O line is locked.
3130292827 26 25 24
P31P30P29P28P27 P26 P25 P24
2322 21 20 19 1817 16
P23P22 P21 P20 P19 P18P17 P16
15 14 1312 11 10 9 8
P15 P14 P13P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3P2 P1 P0
AtmeL
SAM3X / SAM3A [DATASHEET]
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674
31.7.42 PIO Write Protect Mode Register
Name: PIO_WPMR
Address: 0x400E0EE4 (PIOA), 0x400E10E4 (PIOB), 0x400E12E4 (PIOC), 0x400E14E4 (PIOD),
0x400E16E4 (PIOE), 0x400E18E4 (PIOF)
Access: Read-write
Reset: See Table 31-3
For more information on Write Protection Registers, refer to Section 31.6.1 ”Write Protection Registers”.
• WPEN: Write Protect Enable
0: Disables the Write Protect if WPKEY corresponds to 0x50494F (“PIO” in ASCII).
1: Enables the Write Protect if WPKEY corresponds to 0x50494F (“PIO” in ASCII).
Protects the registers:
•“PIO Controller PIO Enable Register” on page 633
•“PIO Controller PIO Disable Register” on page 634
•“PIO Controller Output Enable Register” on page 636
•“PIO Controller Output Disable Register” on page 637
•“PIO Controller Input Filter Enable Register” on page 639
•“PIO Controller Input Filter Disable Register” on page 640
•“PIO Multi-driver Enable Register” on page 650
•“PIO Multi-driver Disable Register” on page 651
•“PIO Pull Up Disable Register” on page 653
•“PIO Pull Up Enable Register” on page 654
•“PIO Peripheral AB Select Register” on page 656
•“PIO Output Write Enable Register” on page 661
•“PIO Output Write Disable Register” on page 662
• WPKEY: Write Protect KEY
Should be written at value 0x50494F (“PIO” in ASCII). Writing any other value in this field aborts the write operation of the
WPEN bit. Always reads as 0.
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
———————WPEN
AtmeL
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SAM3X / SAM3A [DATASHEET]
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31.7.43 PIO Write Protect Status Register
Name: PIO_WPSR
Address: 0x400E0EE8 (PIOA), 0x400E10E8 (PIOB), 0x400E12E8 (PIOC), 0x400E14E8 (PIOD),
0x400E16E8 (PIOE), 0x400E18E8 (PIOF)
Access: Read-only
Reset: See Table 31-3
• WPVS: Write Protect Violation Status
0: No Write Protect Violation has occurred since the last read of the PIO_WPSR register.
1: A Write Protect Violation has occurred since the last read of the PIO_WPSR register. If this violation is an unauthorized
attempt to write a protected register, the associated violation is reported into field WPVSRC.
• WPVSRC: Write Protect Violation Source
When WPVS is active, this field indicates the write-protected register (through address offset or code) in which a write
access has been attempted.
Note: Reading PIO_WPSR automatically clears all fields.
31 30 29 28 27 26 25 24
————————
23 22 21 20 19 18 17 16
WPVSRC
15 14 13 12 11 10 9 8
WPVSRC
76543210
———————WPVS
AtmeL
SAM3X / SAM3A [DATASHEET]
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676
32. Serial Peripheral Interface (SPI)
32.1 Description
The Serial Peripheral Interface (SPI) circuit is a synchronous serial data link that provides communication with
external devices in Master or Slave Mode. It also enables communication between processors if an external
processor is connected to the system.
The Serial Peripheral Interface is essentially a shift register that serially transmits data bits to other SPIs. During a
data transfer, one SPI system acts as the “master”' which controls the data flow, while the other devices act as
“slaves'' which have data shifted into and out by the master. Different CPUs can take turn being masters (Multiple
Master Protocol opposite to Single Master Protocol where one CPU is always the master while all of the others are
always slaves) and one master may simultaneously shift data into multiple slaves. However, only one slave may
drive its output to write data back to the master at any given time.
A slave device is selected when the master asserts its NSS signal. If multiple slave devices exist, the master
generates a separate slave select signal for each slave (NPCS).
The SPI system consists of two data lines and two control lines:
Master Out Slave In (MOSI): This data line supplies the output data from the master shifted into the input(s)
of the slave(s).
Master In Slave Out (MISO): This data line supplies the output data from a slave to the input of the master.
There may be no more than one slave transmitting data during any particular transfer.
Serial Clock (SPCK): This control line is driven by the master and regulates the flow of the data bits. The
master may transmit data at a variety of baud rates; the SPCK line cycles once for each bit that is
transmitted.
Slave Select (NSS): This control line allows slaves to be turned on and off by hardware.
32.2 Embedded Characteristics
Supports Communication with Serial External Devices
̶Four Chip Selects with External Decoder Support Allow Communication with Up to 15 Peripherals
̶Serial Memories, such as DataFlash and 3-wire EEPROMs
̶Serial Peripherals, such as ADCs, DACs, LCD Controllers, CAN Controllers and Sensors
̶External Co-processors
Master or Slave Serial Peripheral Bus Interface
̶8- to 16-bit Programmable Data Length Per Chip Select
̶Programmable Phase and Polarity Per Chip Select
̶Programmable Transfer Delay Between Consecutive Transfers and Delay Before SPI Clock per Chip
Select
̶Programmable Delay Between Chip Selects
̶Selectable Mode Fault Detection
Connection to DMA Channel Capabilities Optimizes Data Transfers
̶One channel for the Receiver, One Channel for the Transmitter
flDDflDDD : 333
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32.3 Block Diagram
Figure 32-1. Block Diagram
32.4 Application Block Diagram
Figure 32-2. Application Block Diagram: Single Master/Multiple Slave Implementation
SPI Interface
Interrupt Control
PIO
Peripheral Bridge
DMA Ch.
AHB Matrix
PMC MCK
SPI Interrupt
SPCK
MISO
MOSI
NPCS0/NSS
NPCS1
NPCS2
NPCS3
APB
SPI Master
SPCK
MISO
MOSI
NPCS0
NPCS1
NPCS2
SPCK
MISO
MOSI
NSS
Slave 0
SPCK
MISO
MOSI
NSS
Slave 1
SPCK
MISO
MOSI
NSS
Slave 2
NC
NPCS3
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32.5 Signal Description
Table 32-1. Signal Description
Pin Name Pin Description
Type
Master Slave
MISO Master In Slave Out Input Output
MOSI Master Out Slave In Output Input
SPCK Serial Clock Output Input
NPCS1-NPCS3 Peripheral Chip Selects Output Unused
NPCS0/NSS Peripheral Chip Select/Slave Select Output Input
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32.6 Product Dependencies
32.6.1 I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines. The programmer
must first program the PIO controllers to assign the SPI pins to their peripheral functions.
32.6.2 Power Management
The SPI may be clocked through the Power Management Controller (PMC), thus the programmer must first
configure the PMC to enable the SPI clock.
32.6.3 Interrupt
The SPI interface has an interrupt line connected to the Interrupt Controller. Handling the SPI interrupt requires
programming the interrupt controller before configuring the SPI.
Table 32-2. I/O Lines
Instance Signal I/O Line Peripheral
SPI0 SPI0_MISO PA25 A
SPI0 SPI0_MOSI PA26 A
SPI0 SPI0_NPCS0 PA28 A
SPI0 SPI0_NPCS1 PA29 A
SPI0 SPI0_NPCS1 PB20 B
SPI0 SPI0_NPCS2 PA30 A
SPI0 SPI0_NPCS2 PB21 B
SPI0 SPI0_NPCS3 PA31 A
SPI0 SPI0_NPCS3 PB23 B
SPI0 SPI0_SPCK PA27 A
SPI1 SPI1_MISO PE28 A
SPI1 SPI1_MOSI PE29 A
SPI1 SPI1_NPCS0 PE31 A
SPI1 SPI1_NPCS1 PF0 A
SPI1 SPI1_NPCS2 PF1 A
SPI1 SPI1_NPCS3 PF2 A
SPI1 SPI1_SPCK PE30 A
Table 32-3. Peripheral IDs
Instance ID
SPI0 24
SPI1 25
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32.7 Functional Description
32.7.1 Modes of Operation
The SPI operates in Master Mode or in Slave Mode.
Operation in Master Mode is programmed by writing at 1 the MSTR bit in the Mode Register. The pins NPCS0 to
NPCS3 are all configured as outputs, the SPCK pin is driven, the MISO line is wired on the receiver input and the
MOSI line driven as an output by the transmitter.
If the MSTR bit is written at 0, the SPI operates in Slave Mode. The MISO line is driven by the transmitter output,
the MOSI line is wired on the receiver input, the SPCK pin is driven by the transmitter to synchronize the receiver.
The NPCS0 pin becomes an input, and is used as a Slave Select signal (NSS). The pins NPCS1 to NPCS3 are not
driven and can be used for other purposes.
The data transfers are identically programmable for both modes of operations. The baud rate generator is
activated only in Master Mode.
32.7.2 Data Transfer
Four combinations of polarity and phase are available for data transfers. The clock polarity is programmed with the
CPOL bit in the Chip Select Register. The clock phase is programmed with the NCPHA bit. These two parameters
determine the edges of the clock signal on which data is driven and sampled. Each of the two parameters has two
possible states, resulting in four possible combinations that are incompatible with one another. Thus, a
master/slave pair must use the same parameter pair values to communicate. If multiple slaves are used and fixed
in different configurations, the master must reconfigure itself each time it needs to communicate with a different
slave.
Table 32-4 shows the four modes and corresponding parameter settings.
Figure 32-3 and Figure 32-4 show examples of data transfers.
Table 32-4. SPI Bus Protocol Mode
SPI Mode CPOL NCPHA Shift SPCK Edge Capture SPCK Edge SPCK Inactive Level
0 0 1 Falling Rising Low
1 0 0 Rising Falling Low
2 1 1 Rising Falling High
3 1 0 Falling Rising High
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Figure 32-3. SPI Transfer Format (NCPHA = 1, 8 bits per transfer)
Figure 32-4. SPI Transfer Format (NCPHA = 0, 8 bits per transfer)
6
*
SPCK
(CPOL = 0)
SPCK
(CPOL = 1)
MOSI
(from master)
MISO
(from slave)
NSS
(to slave)
SPCK cycle (for reference)
MSB
MSB
LSB
LSB
6
6
5
5
4
4
3
3
2
2
1
1
* Not defined, but normally MSB of previous character received.
12345 786
*
SPCK
(CPOL = 0)
SPCK
(CPOL = 1)
12345 7
MOSI
(from master)
MISO
(from slave)
NSS
(to slave)
SPCK cycle (for reference) 8
MSB
MSB
LSB
LSB
6
6
5
5
4
4
3
3
1
1
* Not defined but normally LSB of previous character transmitted.
2
2
6
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32.7.3 Master Mode Operations
When configured in Master Mode, the SPI operates on the clock generated by the internal programmable baud
rate generator. It fully controls the data transfers to and from the slave(s) connected to the SPI bus. The SPI drives
the chip select line to the slave and the serial clock signal (SPCK).
The SPI features two holding registers, the Transmit Data Register and the Receive Data Register, and a single
Shift Register. The holding registers maintain the data flow at a constant rate.
After enabling the SPI, a data transfer begins when the processor writes to the SPI_TDR (Transmit Data Register).
The written data is immediately transferred in the Shift Register and transfer on the SPI bus starts. While the data
in the Shift Register is shifted on the MOSI line, the MISO line is sampled and shifted in the Shift Register.
Receiving data cannot occur without transmitting data. If receiving mode is not needed, for example when
communicating with a slave receiver only (such as an LCD), the receive status flags in the status register can be
discarded.
Before writing the TDR, the PCS field in the SPI_MR register must be set in order to select a slave.
After enabling the SPI, a data transfer begins when the processor writes to the SPI_TDR (Transmit Data Register).
The written data is immediately transferred in the Shift Register and transfer on the SPI bus starts. While the data
in the Shift Register is shifted on the MOSI line, the MISO line is sampled and shifted in the Shift Register.
Transmission cannot occur without reception.
Before writing the TDR, the PCS field must be set in order to select a slave.
If new data is written in SPI_TDR during the transfer, it stays in it until the current transfer is completed. Then, the
received data is transferred from the Shift Register to SPI_RDR, the data in SPI_TDR is loaded in the Shift
Register and a new transfer starts.
The transfer of a data written in SPI_TDR in the Shift Register is indicated by the TDRE bit (Transmit Data
Register Empty) in the Status Register (SPI_SR). When new data is written in SPI_TDR, this bit is cleared. The
TDRE bit is used to trigger the Transmit DMA channel.
The end of transfer is indicated by the TXEMPTY flag in the SPI_SR register. If a transfer delay (DLYBCT) is
greater than 0 for the last transfer, TXEMPTY is set after the completion of said delay. The master clock (MCK)
can be switched off at this time.
The transfer of received data from the Shift Register in SPI_RDR is indicated by the RDRF bit (Receive Data
Register Full) in the Status Register (SPI_SR). When the received data is read, the RDRF bit is cleared.
If the SPI_RDR (Receive Data Register) has not been read before new data is received, the Overrun Error bit
(OVRES) in SPI_SR is set. As long as this flag is set, data is loaded in SPI_RDR. The user has to read the status
register to clear the OVRES bit.
Figure 32-5, shows a block diagram of the SPI when operating in Master Mode. Figure 32-6 on page 684 shows a
flow chart describing how transfers are handled.
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32.7.3.1 Master Mode Block Diagram
Figure 32-5. Master Mode Block Diagram
Shift Register
SPCK
MOSI
LSBMSB
MISO
SPI_RDR
RD
SPI
Clock
TDRE
SPI_TDR
TD
RDRF
OVRES
SPI_CSR0..3
CPOL
NCPHA
BITS
MCK Baud Rate Generator
SPI_CSR0..3
SCBR
NPCS3
NPCS0
NPCS2
NPCS1
NPCS0
0
1
PS
SPI_MR
PCS
SPI_TDR
PCS
MODF
Current
Peripheral
SPI_RDR
PCS
SPI_CSR0..3
CSAAT
PCSDEC
MODFDIS
MSTR
E cw-
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32.7.3.2 Master Mode Flow Diagram
Figure 32-6. Master Mode Flow Diagram
SPI Enable
CSAAT ?
PS ?
1
0
0
1
1
NPCS = SPI_TDR(PCS) NPCS = SPI_MR(PCS)
Delay DLYBS
Serializer = SPI_TDR(TD)
TDRE = 1
Data Transfer
SPI_RDR(RD) = Serializer
RDRF = 1
TDRE ?
NPCS = 0xF
Delay DLYBCS
Fixed
peripheral
Variable
peripheral
Delay DLYBCT
0
1CSAAT ?
0
TDRE ? 1
0
PS ? 0
1
SPI_TDR(PCS)
= NPCS ?
no
yesSPI_MR(PCS)
= NPCS ?
no
NPCS = 0xF
Delay DLYBCS
NPCS = SPI_TDR(PCS)
NPCS = 0xF
Delay DLYBCS
NPCS = SPI_MR(PCS),
SPI_TDR(PCS)
Fixed
peripheral
Variable
peripheral
- NPCS defines the current Chip Select
- CSAAT, DLYBS, DLYBCT refer to the fields of the
Chip Select Register corresponding to the Current Chip Select
- When NPCS is 0xF, CSAAT is 0.
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Figure 32-7 shows Transmit Data Register Empty (TDRE), Receive Data Register (RDRF) and Transmission
Register Empty (TXEMPTY) status flags behavior within the SPI_SR (Status Register) during an 8-bit data transfer
in fixed mode and no Peripheral Data Controller involved.
Figure 32-7. Status Register Flags Behavior
32.7.3.3 Clock Generation
The SPI Baud rate clock is generated by dividing the Master Clock (MCK), by a value between 1 and 255.
This allows a maximum operating baud rate at up to Master Clock and a minimum operating baud rate of MCK
divided by 255.
Programming the SCBR field at 0 is forbidden. Triggering a transfer while SCBR is at 0 can lead to unpredictable
results.
At reset, SCBR is 0 and the user has to program it at a valid value before performing the first transfer.
The divisor can be defined independently for each chip select, as it has to be programmed in the SCBR field of the
Chip Select Registers. This allows the SPI to automatically adapt the baud rate for each interfaced peripheral
without reprogramming.
32.7.3.4 Transfer Delays
Figure 32-8 shows a chip select transfer change and consecutive transfers on the same chip select. Three delays
can be programmed to modify the transfer waveforms:
The delay between chip selects, programmable only once for all the chip selects by writing the DLYBCS field
in the Mode Register. Allows insertion of a delay between release of one chip select and before assertion of
a new one.
The delay before SPCK, independently programmable for each chip select by writing the field DLYBS.
Allows the start of SPCK to be delayed after the chip select has been asserted.
The delay between consecutive transfers, independently programmable for each chip select by writing the
DLYBCT field. Allows insertion of a delay between two transfers occurring on the same chip select
6
SPCK
MOSI
(from master)
MISO
(from slave)
NPCS0
MSB
MSB
LSB
LSB
6
6
5
5
4
4
3
3
2
2
1
1
12345 786
RDRF
TDRE
TXEMPTY
Write in
SPI_TDR
RDR read
shift register empty
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These delays allow the SPI to be adapted to the interfaced peripherals and their speed and bus release time.
Figure 32-8. Programmable Delays
32.7.3.5 Peripheral Selection
The serial peripherals are selected through the assertion of the NPCS0 to NPCS3 signals. By default, all the
NPCS signals are high before and after each transfer.
Fixed Peripheral Select: SPI exchanges data with only one peripheral
Fixed Peripheral Select is activated by writing the PS bit to zero in SPI_MR (Mode Register). In this case, the
current peripheral is defined by the PCS field in SPI_MR and the PCS field in the SPI_TDR has no effect.
Variable Peripheral Select: Data can be exchanged with more than one peripheral without having to
reprogram the NPCS field in the SPI_MR register.
Variable Peripheral Select is activated by setting PS bit to one. The PCS field in SPI_TDR is used to select the
current peripheral. This means that the peripheral selection can be defined for each new data. The value to write in
the SPI_TDR register as the following format.
[xxxxxxx(7-bit) + LASTXFER(1-bit)(1)+ xxxx(4-bit) + PCS (4-bit) + DATA (8 to 16-bit)] with PCS equals to the chip
select to assert as defined in Section 32.8.4 (SPI Transmit Data Register) and LASTXFER bit at 0 or 1 depending
on CSAAT bit.
Note: 1. Optional.
CSAAT, LASTXFER and CSNAAT bits are discussed in Section 32.7.3.9 ”Peripheral Deselection with DMAC” .
If LASTXFER is used, the command must be issued before writing the last character. Instead of LASTXFER, the
user can use the SPIDIS command. After the end of the DMA transfer, wait for the TXEMPTY flag, then write
SPIDIS into the SPI_CR register (this will not change the configuration register values); the NPCS will be
deactivated after the last character transfer. Then, another DMA transfer can be started if the SPIEN was
previously written in the SPI_CR register.
32.7.3.6 SPI Direct Access Memory Controller (DMAC)
In both fixed and variable mode the Direct Memory Access Controller (DMAC) can be used to reduce processor
overhead.
The Fixed Peripheral Selection allows buffer transfers with a single peripheral. Using the DMAC is an optimal
means, as the size of the data transfer between the memory and the SPI is either 8 bits or 16 bits. However,
changing the peripheral selection requires the Mode Register to be reprogrammed.
The Variable Peripheral Selection allows buffer transfers with multiple peripherals without reprogramming the
Mode Register. Data written in SPI_TDR is 32 bits wide and defines the real data to be transmitted and the
peripheral it is destined to. Using the DMAC in this mode requires 32-bit wide buffers, with the data in the LSBs
and the PCS and LASTXFER fields in the MSBs, however the SPI still controls the number of bits (8 to16) to be
DLYBCSDLYBSDLYBCT DLYBCT
Chip Select 1
Chip Select 2
SPCK
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transferred through MISO and MOSI lines with the chip select configuration registers. This is not the optimal
means in term of memory size for the buffers, but it provides a very effective means to exchange data with several
peripherals without any intervention of the processor.
32.7.3.7 Peripheral Chip Select Decoding
The user can program the SPI to operate with up to 15 peripherals by decoding the four Chip Select lines, NPCS0
to NPCS3 with 1 of up to 16 decoder/demultiplexer. This can be enabled by writing the PCSDEC bit at 1 in the
Mode Register (SPI_MR).
When operating without decoding, the SPI makes sure that in any case only one chip select line is activated, i.e.,
one NPCS line driven low at a time. If two bits are defined low in a PCS field, only the lowest numbered chip select
is driven low.
When operating with decoding, the SPI directly outputs the value defined by the PCS field on NPCS lines of either
the Mode Register or the Transmit Data Register (depending on PS).
As the SPI sets a default value of 0xF on the chip select lines (i.e. all chip select lines at 1) when not processing
any transfer, only 15 peripherals can be decoded.
The SPI has only four Chip Select Registers, not 15. As a result, when decoding is activated, each chip select
defines the characteristics of up to four peripherals. As an example, SPI_CRS0 defines the characteristics of the
externally decoded peripherals 0 to 3, corresponding to the PCS values 0x0 to 0x3. Thus, the user has to make
sure to connect compatible peripherals on the decoded chip select lines 0 to 3, 4 to 7, 8 to 11 and 12 to 14. Figure
32-9 below shows such an implementation.
If the CSAAT bit is used, with or without the DMAC, the Mode Fault detection for NPCS0 line must be disabled.
This is not needed for all other chip select lines since Mode Fault Detection is only on NPCS0.
Figure 32-9. Chip Select Decoding Application Block Diagram: Single Master/Multiple Slave Implementation
SPI Master
SPCK
MISO
MOSI
NPCS0
NPCS1
NPCS2
SPCK
1-of-n Decoder/Demultiplexer
MISOMOSI
NSS
Slave 0
SPCK MISOMOSI
NSS
Slave 1
SPCK MISOMOSI
NSS
Slave 14
NPCS3
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32.7.3.8 Peripheral Deselection without DMAC
During a transfer of more than one data on a Chip Select without the DMAC, the SPI_TDR is loaded by the
processor, the flag TDRE rises as soon as the content of the SPI_TDR is transferred into the internal shift register.
When this flag is detected high, the SPI_TDR can be reloaded. If this reload by the processor occurs before the
end of the current transfer and if the next transfer is performed on the same chip select as the current transfer, the
Chip Select is not de-asserted between the two transfers. But depending on the application software handling the
SPI status register flags (by interrupt or polling method) or servicing other interrupts or other tasks, the processor
may not reload the SPI_TDR in time to keep the chip select active (low). A null Delay Between Consecutive
Transfer (DLYBCT) value in the SPI_CSR register, will give even less time for the processor to reload the
SPI_TDR. With some SPI slave peripherals, requiring the chip select line to remain active (low) during a full set of
transfers might lead to communication errors.
To facilitate interfacing with such devices, the Chip Select Register [CSR0...CSR3] can be programmed with the
CSAAT bit (Chip Select Active After Transfer) at 1. This allows the chip select lines to remain in their current state
(low = active) until transfer to another chip select is required. Even if the SPI_TDR is not reloaded the chip select
will remain active. To have the chip select line to raise at the end of the transfer the Last transfer Bit (LASTXFER)
in the SPI_MR register must be set at 1 before writing the last data to transmit into the SPI_TDR.
32.7.3.9 Peripheral Deselection with DMAC
When the Direct Memory Access Controller is used, the chip select line will remain low during the whole transfer
since the TDRE flag is managed by the DMAC itself. The reloading of the SPI_TDR by the DMAC is done as soon
as TDRE flag is set to one. In this case the use of CSAAT bit might not be needed. However, it may happen that
when other DMAC channels connected to other peripherals are in use as well, the SPI DMAC might be delayed by
another (DMAC with a higher priority on the bus). Having DMAC buffers in slower memories like flash memory or
SDRAM compared to fast internal SRAM, may lengthen the reload time of the SPI_TDR by the DMAC as well. This
means that the SPI_TDR might not be reloaded in time to keep the chip select line low. In this case the chip select
line may toggle between data transfer and according to some SPI Slave devices, the communication might get
lost. The use of the CSAAT bit might be needed.
When the CSAAT bit is set at 0, the NPCS does not rise in all cases between two transfers on the same peripheral.
During a transfer on a Chip Select, the flag TDRE rises as soon as the content of the SPI_TDR is transferred into
the internal shifter. When this flag is detected the SPI_TDR can be reloaded. If this reload occurs before the end of
the current transfer and if the next transfer is performed on the same chip select as the current transfer, the Chip
Select is not de-asserted between the two transfers. This might lead to difficulties for interfacing with some serial
peripherals requiring the chip select to be de-asserted after each transfer. To facilitate interfacing with such
devices, the Chip Select Register can be programmed with the CSNAAT bit (Chip Select Not Active After Transfer)
at 1. This allows to de-assert systematically the chip select lines during a time DLYBCS. (The value of the
CSNAAT bit is taken into account only if the CSAAT bit is set at 0 for the same Chip Select).
Figure 32-10 shows different peripheral deselection cases and the effect of the CSAAT and CSNAAT bits.
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Figure 32-10. Peripheral Deselection
32.7.3.10Mode Fault Detection
A mode fault is detected when the SPI is programmed in Master Mode and a low level is driven by an external
master on the NPCS0/NSS signal. In this case, multi-master configuration, NPCS0, MOSI, MISO and SPCK pins
must be configured in open drain (through the PIO controller). When a mode fault is detected, the MODF bit in the
SPI_SR is set until the SPI_SR is read and the SPI is automatically disabled until re-enabled by writing the SPIEN
bit in the SPI_CR (Control Register) at 1.
A
NPCS[0..3]
Write SPI_TDR
TDRE
NPCS[0..3]
Write SPI_TDR
TDRE
NPCS[0..3]
Write SPI_TDR
TDRE
DLYBCS
PCS = A
DLYBCS
DLYBCT
A
PCS = B
B
DLYBCS
PCS = A
DLYBCS
DLYBCT
A
PCS = B
B
DLYBCS
DLYBCT
PCS=A
A
DLYBCS
DLYBCT
A
PCS = A
AA
DLYBCT
AA
CSAAT = 0 and CSNAAT = 0
DLYBCT
AA
CSAAT = 1 and CSNAAT= 0 / 1
A
DLYBCS
PCS = A
DLYBCT
AA
CSAAT = 0 and CSNAAT = 1
NPCS[0..3]
Write SPI_TDR
TDRE
PCS = A
DLYBCT
AA
CSAAT = 0 and CSNAAT = 0
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By default, the Mode Fault detection circuitry is enabled. The user can disable Mode Fault detection by setting the
MODFDIS bit in the SPI Mode Register (SPI_MR).
32.7.4 SPI Slave Mode
When operating in Slave Mode, the SPI processes data bits on the clock provided on the SPI clock pin (SPCK).
The SPI waits for NSS to go active before receiving the serial clock from an external master. When NSS falls, the
clock is validated on the serializer, which processes the number of bits defined by the BITS field of the Chip Select
Register 0 (SPI_CSR0). These bits are processed following a phase and a polarity defined respectively by the
NCPHA and CPOL bits of the SPI_CSR0. Note that BITS, CPOL and NCPHA of the other Chip Select Registers
have no effect when the SPI is programmed in Slave Mode.
The bits are shifted out on the MISO line and sampled on the MOSI line.
(For more information on BITS field, see also, the (Note:) below the register table; Section 32.8.9 “SPI Chip Select
Register” on page 703.)
When all the bits are processed, the received data is transferred in the Receive Data Register and the RDRF bit
rises. If the SPI_RDR (Receive Data Register) has not been read before new data is received, the Overrun Error
bit (OVRES) in SPI_SR is set. As long as this flag is set, data is loaded in SPI_RDR. The user has to read the
status register to clear the OVRES bit.
When a transfer starts, the data shifted out is the data present in the Shift Register. If no data has been written in
the Transmit Data Register (SPI_TDR), the last data received is transferred. If no data has been received since the
last reset, all bits are transmitted low, as the Shift Register resets at 0.
When a first data is written in SPI_TDR, it is transferred immediately in the Shift Register and the TDRE bit rises. If
new data is written, it remains in SPI_TDR until a transfer occurs, i.e. NSS falls and there is a valid clock on the
SPCK pin. When the transfer occurs, the last data written in SPI_TDR is transferred in the Shift Register and the
TDRE bit rises. This enables frequent updates of critical variables with single transfers.
Then, a new data is loaded in the Shift Register from the Transmit Data Register. In case no character is ready to
be transmitted, i.e. no character has been written in SPI_TDR since the last load from SPI_TDR to the Shift
Register, the Shift Register is not modified and the last received character is retransmitted. In this case the
Underrun Error Status Flag (UNDES) is set in the SPI_SR.
Figure 32-11 shows a block diagram of the SPI when operating in Slave Mode.
Figure 32-11. Slave Mode Functional Bloc Diagram
Shift Register
SPCK
SPIENS
LSBMSB
NSS
MOSI
SPI_RDR
RD
SPI
Clock
TDRE
SPI_TDR
TD
RDRF
OVRES
SPI_CSR0
CPOL
NCPHA
BITS
SPIEN
SPIDIS
MISO
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32.7.5 Write Protected Registers
To prevent any single software error that may corrupt SPI behavior, the registers listed below can be write-
protected by setting the WPEN bit in the SPI Write Protection Mode Register (SPI_WPMR).
If a write access in a write-protected register is detected, then the WPVS flag in the SPI Write Protection Status
Register (SPI_WPSR) is set and the field WPVSRC indicates in which register the write access has been
attempted.
The WPVS flag is automatically reset after reading the SPI Write Protection Status Register (SPI_WPSR).
List of the write-protected registers:
Section 32.8.2 ”SPI Mode Register”
Section 32.8.9 ”SPI Chip Select Register”
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32.8 Serial Peripheral Interface (SPI) User Interface
Table 32-5. Register Mapping
Offset Register Name Access Reset
0x00 Control Register SPI_CR Write-only ---
0x04 Mode Register SPI_MR Read-write 0x0
0x08 Receive Data Register SPI_RDR Read-only 0x0
0x0C Transmit Data Register SPI_TDR Write-only ---
0x10 Status Register SPI_SR Read-only 0x000000F0
0x14 Interrupt Enable Register SPI_IER Write-only ---
0x18 Interrupt Disable Register SPI_IDR Write-only ---
0x1C Interrupt Mask Register SPI_IMR Read-only 0x0
0x20 - 0x2C Reserved
0x30 Chip Select Register 0 SPI_CSR0 Read-write 0x0
0x34 Chip Select Register 1 SPI_CSR1 Read-write 0x0
0x38 Chip Select Register 2 SPI_CSR2 Read-write 0x0
0x3C Chip Select Register 3 SPI_CSR3 Read-write 0x0
0x4C - 0xE0 Reserved – – –
0xE4 Write Protection Control Register SPI_WPMR Read-write 0x0
0xE8 Write Protection Status Register SPI_WPSR Read-only 0x0
0x00E8 - 0x00F8 Reserved – – –
0x00FC Reserved – – –
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32.8.1 SPI Control Register
Name: SPI_CR
Address: 0x40008000 (0), 0x4000C000 (1)
Access: Write-only
• SPIEN: SPI Enable
0 = No effect.
1 = Enables the SPI to transfer and receive data.
• SPIDIS: SPI Disable
0 = No effect.
1 = Disables the SPI.
As soon as SPIDIS is set, SPI finishes its transfer.
All pins are set in input mode and no data is received or transmitted.
If a transfer is in progress, the transfer is finished before the SPI is disabled.
If both SPIEN and SPIDIS are equal to one when the control register is written, the SPI is disabled.
• SWRST: SPI Software Reset
0 = No effect.
1 = Reset the SPI. A software-triggered hardware reset of the SPI interface is performed.
The SPI is in slave mode after software reset.
DMAC channels are not affected by software reset.
• LASTXFER: Last Transfer
0 = No effect.
1 = The current NPCS will be deasserted after the character written in TD has been transferred. When CSAAT is set, this
allows to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD
transfer has completed.
Refer to Section 32.7.3.5 ”Peripheral Selection” for more details.
3130292827 26 25 24
–––––––LASTXFER
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
SWRST–––––SPIDISSPIEN
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32.8.2 SPI Mode Register
Name: SPI_MR
Address: 0x40008004 (0), 0x4000C004 (1)
Access: Read-write
This register can only be written if the WPEN bit is cleared in ”SPI Write Protection Mode Register”.
• MSTR: Master/Slave Mode
0 = SPI is in Slave mode.
1 = SPI is in Master mode.
• PS: Peripheral Select
0 = Fixed Peripheral Select.
1 = Variable Peripheral Select.
• PCSDEC: Chip Select Decode
0 = The chip selects are directly connected to a peripheral device.
1 = The four chip select lines are connected to a 4- to 16-bit decoder.
When PCSDEC equals one, up to 15 Chip Select signals can be generated with the four lines using an external 4- to 16-bit
decoder. The Chip Select Registers define the characteristics of the 15 chip selects according to the following rules:
SPI_CSR0 defines peripheral chip select signals 0 to 3.
SPI_CSR1 defines peripheral chip select signals 4 to 7.
SPI_CSR2 defines peripheral chip select signals 8 to 11.
SPI_CSR3 defines peripheral chip select signals 12 to 14.
• MODFDIS: Mode Fault Detection
0 = Mode fault detection is enabled.
1 = Mode fault detection is disabled.
• WDRBT: Wait Data Read Before Transfer
0 = No Effect. In master mode, a transfer can be initiated whatever the state of the Receive Data Register is.
1 = In Master Mode, a transfer can start only if the Receive Data Register is empty, i.e. does not contain any unread data.
This mode prevents overrun error in reception.
3130292827 26 25 24
DLYBCS
2322 21 20 19 1817 16
–––– PCS
15 14 1312 11 10 9 8
––––––––
76543210
LLB – WDRBT MODFDIS–PCSDEC PSMSTR
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• LLB: Local Loopback Enable
0 = Local loopback path disabled.
1 = Local loopback path enabled
LLB controls the local loopback on the data serializer for testing in Master Mode only. (MISO is internally connected on
MOSI.)
• PCS: Peripheral Chip Select
This field is only used if Fixed Peripheral Select is active (PS = 0).
If PCSDEC = 0:
PCS = xxx0 NPCS[3:0] = 1110
PCS = xx01 NPCS[3:0] = 1101
PCS = x011 NPCS[3:0] = 1011
PCS = 0111 NPCS[3:0] = 0111
PCS = 1111 forbidden (no peripheral is selected)
(x = don’t care)
If PCSDEC = 1:
NPCS[3:0] output signals = PCS.
• DLYBCS: Delay Between Chip Selects
This field defines the delay from NPCS inactive to the activation of another NPCS. The DLYBCS time guarantees non-
overlapping chip selects and solves bus contentions in case of peripherals having long data float times.
If DLYBCS is less than or equal to six, six MCK periods will be inserted by default.
Otherwise, the following equation determines the delay:
Delay Between Chip Selects DLYBCS
MCK
-----------------------
=
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32.8.3 SPI Receive Data Register
Name: SPI_RDR
Address: 0x40008008 (0), 0x4000C008 (1)
Access: Read-only
• RD: Receive Data
Data received by the SPI Interface is stored in this register right-justified. Unused bits read zero.
• PCS: Peripheral Chip Select
In Master Mode only, these bits indicate the value on the NPCS pins at the end of a transfer. Otherwise, these bits read
zero.
Note: When using variable peripheral select mode (PS = 1 in SPI_MR) it is mandatory to also set the WDRBT field to 1 if the SPI_RDR
PCS field is to be processed.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
–––– PCS
15 14 1312 11 10 9 8
RD
76543210
RD
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32.8.4 SPI Transmit Data Register
Name: SPI_TDR
Address: 0x4000800C (0), 0x4000C00C (1)
Access: Write-only
• TD: Transmit Data
Data to be transmitted by the SPI Interface is stored in this register. Information to be transmitted must be written to the
transmit data register in a right-justified format.
• PCS: Peripheral Chip Select
This field is only used if Variable Peripheral Select is active (PS = 1).
If PCSDEC = 0:
PCS = xxx0 NPCS[3:0] = 1110
PCS = xx01 NPCS[3:0] = 1101
PCS = x011 NPCS[3:0] = 1011
PCS = 0111 NPCS[3:0] = 0111
PCS = 1111 forbidden (no peripheral is selected)
(x = don’t care)
If PCSDEC = 1:
NPCS[3:0] output signals = PCS
• LASTXFER: Last Transfer
0 = No effect.
1 = The current NPCS will be deasserted after the character written in TD has been transferred. When CSAAT is set, this
allows to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD
transfer has completed.
This field is only used if Variable Peripheral Select is active (PS = 1).
3130292827 26 25 24
–––––––LASTXFER
2322 21 20 19 1817 16
–––– PCS
15 14 1312 11 10 9 8
TD
76543210
TD
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32.8.5 SPI Status Register
Name: SPI_SR
Address: 0x40008010 (0), 0x4000C010 (1)
Access: Read-only
• RDRF: Receive Data Register Full
0 = No data has been received since the last read of SPI_RDR
1 = Data has been received and the received data has been transferred from the serializer to SPI_RDR since the last read
of SPI_RDR.
• TDRE: Transmit Data Register Empty
0 = Data has been written to SPI_TDR and not yet transferred to the serializer.
1 = The last data written in the Transmit Data Register has been transferred to the serializer.
TDRE equals zero when the SPI is disabled or at reset. The SPI enable command sets this bit to one.
• MODF: Mode Fault Error
0 = No Mode Fault has been detected since the last read of SPI_SR.
1 = A Mode Fault occurred since the last read of the SPI_SR.
• OVRES: Overrun Error Status
0 = No overrun has been detected since the last read of SPI_SR.
1 = An overrun has occurred since the last read of SPI_SR.
An overrun occurs when SPI_RDR is loaded at least twice from the serializer since the last read of the SPI_RDR.
• NSSR: NSS Rising
0 = No rising edge detected on NSS pin since last read.
1 = A rising edge occurred on NSS pin since last read.
• TXEMPTY: Transmission Registers Empty
0 = As soon as data is written in SPI_TDR.
1 = SPI_TDR and internal shifter are empty. If a transfer delay has been defined, TXEMPTY is set after the completion of
such delay.
• UNDES: Underrun Error Status (Slave Mode Only)
0 = No underrun has been detected since the last read of SPI_SR.
1 = A transfer begins whereas no data has been loaded in the Transmit Data Register.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
–––––––SPIENS
15 14 1312 11 10 9 8
–––––UNDESTXEMPTY NSSR
76543210
––––OVRESMODF TDRE RDRF
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• SPIENS: SPI Enable Status
0 = SPI is disabled.
1 = SPI is enabled.
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32.8.6 SPI Interrupt Enable Register
Name: SPI_IER
Address: 0x40008014 (0), 0x4000C014 (1)
Access: Write-only
0 = No effect.
1 = Enables the corresponding interrupt.
• RDRF: Receive Data Register Full Interrupt Enable
• TDRE: SPI Transmit Data Register Empty Interrupt Enable
• MODF: Mode Fault Error Interrupt Enable
• OVRES: Overrun Error Interrupt Enable
• NSSR: NSS Rising Interrupt Enable
• TXEMPTY: Transmission Registers Empty Enable
• UNDES: Underrun Error Interrupt Enable
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––––UNDESTXEMPTY NSSR
76543210
––––OVRESMODF TDRE RDRF
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32.8.7 SPI Interrupt Disable Register
Name: SPI_IDR
Address: 0x40008018 (0), 0x4000C018 (1)
Access: Write-only
0 = No effect.
1 = Disables the corresponding interrupt.
• RDRF: Receive Data Register Full Interrupt Disable
• TDRE: SPI Transmit Data Register Empty Interrupt Disable
• MODF: Mode Fault Error Interrupt Disable
• OVRES: Overrun Error Interrupt Disable
• NSSR: NSS Rising Interrupt Disable
• TXEMPTY: Transmission Registers Empty Disable
• UNDES: Underrun Error Interrupt Disable
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––––UNDESTXEMPTY NSSR
76543210
––––OVRESMODF TDRE RDRF
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32.8.8 SPI Interrupt Mask Register
Name: SPI_IMR
Address: 0x4000801C (0), 0x4000C01C (1)
Access: Read-only
0 = The corresponding interrupt is not enabled.
1 = The corresponding interrupt is enabled.
• RDRF: Receive Data Register Full Interrupt Mask
• TDRE: SPI Transmit Data Register Empty Interrupt Mask
• MODF: Mode Fault Error Interrupt Mask
• OVRES: Overrun Error Interrupt Mask
• NSSR: NSS Rising Interrupt Mask
• TXEMPTY: Transmission Registers Empty Mask
• UNDES: Underrun Error Interrupt Mask
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––––UNDESTXEMPTY NSSR
76543210
––––OVRESMODF TDRE RDRF
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32.8.9 SPI Chip Select Register
Name: SPI_CSRx[x=0..3]
Address: 0x40008030 (0), 0x4000C030 (1)
Access: Read/Write
This register can only be written if the WPEN bit is cleared in ”SPI Write Protection Mode Register”.
Note: SPI_CSRx registers must be written even if the user wants to use the defaults. The BITS field will not be updated with the
translated value unless the register is written.
• CPOL: Clock Polarity
0 = The inactive state value of SPCK is logic level zero.
1 = The inactive state value of SPCK is logic level one.
CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with NCPHA to produce the
required clock/data relationship between master and slave devices.
• NCPHA: Clock Phase
0 = Data is changed on the leading edge of SPCK and captured on the following edge of SPCK.
1 = Data is captured on the leading edge of SPCK and changed on the following edge of SPCK.
NCPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. NCPHA is
used with CPOL to produce the required clock/data relationship between master and slave devices.
• CSNAAT: Chip Select Not Active After Transfer (Ignored if CSAAT = 1)
0 = The Peripheral Chip Select does not rise between two transfers if the SPI_TDR is reloaded before the end of the first
transfer and if the two transfers occur on the same Chip Select.
1 = The Peripheral Chip Select rises systematically after each transfer performed on the same slave. It remains active after
the end of transfer for a minimal duration of:
– (if DLYBCT field is different from 0)
– (if DLYBCT field equals 0)
• CSAAT: Chip Select Active After Transfer
0 = The Peripheral Chip Select Line rises as soon as the last transfer is achieved.
1 = The Peripheral Chip Select does not rise after the last transfer is achieved. It remains active until a new transfer is
requested on a different chip select.
3130292827 26 25 24
DLYBCT
2322 21 20 19 1817 16
DLYBS
15 14 1312 11 10 9 8
SCBR
76543210
BITSCSAAT CSNAAT NCPHA CPOL
DLYBCT
MCK
-----------------------
DLYBCT 1+
MCK
---------------------------------
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• BITS: Bits Per Transfer
(See the (Note:) below the register table; Section 32.8.9 “SPI Chip Select Register” on page 703.)
The BITS field determines the number of data bits transferred. Reserved values should not be used.
• SCBR: Serial Clock Baud Rate
In Master Mode, the SPI Interface uses a modulus counter to derive the SPCK baud rate from the Master Clock MCK. The
Baud rate is selected by writing a value from 1 to 255 in the SCBR field. The following equations determine the SPCK baud
rate:
Programming the SCBR field at 0 is forbidden. Triggering a transfer while SCBR is at 0 can lead to unpredictable results.
At reset, SCBR is 0 and the user has to program it at a valid value before performing the first transfer.
Note: If one of the SCBR fields inSPI_CSRx is set to 1, the other SCBR fields in SPI_CSRx must be set to 1 as well, if they are required
to process transfers. If they are not used to transfer data, they can be set at any value.
• DLYBS: Delay Before SPCK
This field defines the delay from NPCS valid to the first valid SPCK transition.
When DLYBS equals zero, the NPCS valid to SPCK transition is 1/2 the SPCK clock period.
Otherwise, the following equations determine the delay:
• DLYBCT: Delay Between Consecutive Transfers
This field defines the delay between two consecutive transfers with the same peripheral without removing the chip select.
The delay is always inserted after each transfer and before removing the chip select if needed.
When DLYBCT equals zero, no delay between consecutive transfers is inserted and the clock keeps its duty cycle over the
character transfers.
Value Name Description
0 8_BIT 8 bits for transfer
1 9_BIT 9 bits for transfer
2 10_BIT 10 bits for transfer
3 11_BIT 11 bits for transfer
4 12_BIT 12 bits for transfer
5 13_BIT 13 bits for transfer
6 14_BIT 14 bits for transfer
7 15_BIT 15 bits for transfer
8 16_BIT 16 bits for transfer
9– Reserved
10 – Reserved
11 – Reserved
12 – Reserved
13 – Reserved
14 – Reserved
15 – Reserved
SPCK Baudrate MCK
SCBR
---------------
=
Delay Before SPCK DLYBS
MCK
-------------------
=
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Otherwise, the following equation determines the delay:
Delay Between Consecutive Transfers 32 DLYBCT×
MCK
------------------------------------
=
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32.8.10 SPI Write Protection Mode Register
Name: SPI_WPMR
Address: 0x400080E4 (0), 0x4000C0E4 (1)
Access: Read-write
• WPEN: Write Protection Enable
0: The Write Protection is Disabled
1: The Write Protection is Enabled
• WPKEY: Write Protection Key Password
If a value is written in WPEN, the value is taken into account only if WPKEY is written with “SPI” (SPI written in ASCII
Code, ie 0x535049 in hexadecimal).
List of the write-protected registers:
Section 32.8.2 ”SPI Mode Register”
Section 32.8.9 ”SPI Chip Select Register”
3130292827 26 25 24
WPKEY
2322 21 20 19 1817 16
WPKEY
15 14 1312 11 10 9 8
WPKEY
76543210
-------WPEN
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32.8.11 SPI Write Protection Status Register
Name: SPI_WPSR
Address: 0x400080E8 (0), 0x4000C0E8 (1)
Access: Read-only
• WPVS: Write Protection Violation Status
0 = No Write Protect Violation has occurred since the last read of the SPI_WPSR register.
1 = A Write Protect Violation has occurred since the last read of the SPI_WPSR register. If this violation is an unauthorized
attempt to write a protected register, the associated violation is reported into field WPVSRC.
• WPVSRC: Write Protection Violation Source
This Field indicates the APB Offset of the register concerned by the violation (SPI_MR or SPI_CSRx)
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
WPVSRC
76543210
–––––––
WPVS
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33. Two-wire Interface (TWI)
33.1 Description
The Atmel Two-wire Interface (TWI) interconnects components on a unique two-wire bus, made up of one clock
line and one data line with speeds of up to 400 Kbits per second, based on a byte-oriented transfer format. It can
be used with any Atmel Two-wire Interface bus Serial EEPROM and I²C compatible device such as Real Time
Clock (RTC), Dot Matrix/Graphic LCD Controllers and Temperature Sensor, to name but a few. The TWI is
programmable as a master or a slave with sequential or single-byte access. Multiple master capability is
supported. 20
Arbitration of the bus is performed internally and puts the TWI in slave mode automatically if the bus arbitration is
lost.
A configurable baud rate generator permits the output data rate to be adapted to a wide range of core clock
frequencies.
Below, Table 33-1 lists the compatibility level of the Atmel Two-wire Interface in Master Mode and a full I2C
compatible device.
Note: 1. START + b000000001 + Ack + Sr
33.2 Embedded Characteristics
2 x TWI
Compatible with Atmel Two-wire Interface Serial Memory and I²C Compatible Devices(Note:)
One, Two or Three Bytes for Slave Address
Sequential Read-write Operations
Master, Multi-master and Slave Mode Operation
Bit Rate: Up to 400 Kbits
General Call Supported in Slave mode
SMBUS Quick Command Supported in Master Mode
Connection to Peripheral DMA Controller (PDC) Channel Capabilities Optimizes Data Transfers in Master
Mode Only
̶One Channel for the Receiver, One Channel for the Transmitter
̶Next Buffer Support
Note: See Table 33-1 for details on compatibility with I²C Standard.
Table 33-1. Atmel TWI compatibility with i2C Standard
I2C Standard Atmel TWI
Standard Mode Speed (100 KHz) Supported
Fast Mode Speed (400 KHz) Supported
7 or 10 bits Slave Addressing Supported
START BYTE(1) Not Supported
Repeated Start (Sr) Condition Supported
ACK and NACK Management Supported
Slope control and input filtering (Fast mode) Not Supported
Clock stretching Supported
Multi Master Capability Supported
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33.3 List of Abbreviations
33.4 Block Diagram
Figure 33-1. Block Diagram
Table 33-2. Abbreviations
Abbreviation Description
TWI Two-wire Interface
A Acknowledge
NA Non Acknowledge
PStop
SStart
Sr Repeated Start
SADR Slave Address
ADR Any address except SADR
RRead
WWrite
APB Bridge
PMC MCK
Two-wire
Interface
PIO
NVIC
TWI
Interrupt
TWCK
TWD
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33.5 Application Block Diagram
Figure 33-2. Application Block Diagram
33.5.1 I/O Lines Description
33.6 Product Dependencies
33.6.1 I/O Lines
Both TWD and TWCK are bidirectional lines, connected to a positive supply voltage via a current source or pull-up
resistor (see Figure 33-2 on page 710). When the bus is free, both lines are high. The output stages of devices
connected to the bus must have an open-drain or open-collector to perform the wired-AND function.
TWD and TWCK pins may be multiplexed with PIO lines. To enable the TWI, the programmer must perform the
following step:
Program the PIO controller to dedicate TWD and TWCK as peripheral lines.
The user must not program TWD and TWCK as open-drain. It is already done by the hardware.
33.6.2 Power Management
Enable the peripheral clock.
The TWI interface may be clocked through the Power Management Controller (PMC), thus the programmer must
first configure the PMC to enable the TWI clock.
Host with
TWI
Interface
TWD
TWCK
Atmel TWI
Serial EEPROM I²C RTC I²C LCD
Controller
Slave 1 Slave 2 Slave 3
VDD
I²C Temp.
Sensor
Slave 4
Rp: Pull up value as given by the I²C Standard
Rp Rp
Table 33-3. I/O Lines Description
Pin Name Pin Description Type
TWD Two-wire Serial DataInput/Output
TWCK Two-wire Serial Clock Input/Output
Table 33-4. I/O Lines
Instance Signal I/O Line Peripheral
TWI0 TWCK0 PA18 A
TWI0 TWD0 PA17 A
TWI1 TWCK1 PB13 A
TWI1 TWD1 PB12 A
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33.6.3 Interrupt
The TWI interface has an interrupt line connected to the Nested Vector Interrupt Controller (NVIC). In order to
handle interrupts, the NVIC must be programmed before configuring the TWI.
Table 33-5. Peripheral IDs
Instance ID
TWI0 22
TWI1 23
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33.7 Functional Description
33.7.1 Transfer Format
The data put on the TWD line must be 8 bits long. Data is transferred MSB first; each byte must be followed by an
acknowledgement. The number of bytes per transfer is unlimited (see Figure 33-4).
Each transfer begins with a START condition and terminates with a STOP condition (see Figure 33-3).
A high-to-low transition on the TWD line while TWCK is high defines the START condition.
A low-to-high transition on the TWD line while TWCK is high defines a STOP condition.
Figure 33-3. START and STOP Conditions
Figure 33-4. Transfer Format
33.7.2 Modes of Operation
The TWI has six modes of operations:
Master transmitter mode
Master receiver mode
Multi-master transmitter mode
Multi-master receiver mode
Slave transmitter mode
Slave receiver mode
These modes are described in the following chapters.
TWD
TWCK
Start Stop
TWD
TWCK
Start Address R/W Ack DataAck DataAck Stop
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33.8 Master Mode
33.8.1 Definition
The Master is the device that starts a transfer, generates a clock and stops it.
33.8.2 Application Block Diagram
Figure 33-5. Master Mode Typical Application Block Diagram
33.8.3 Programming Master Mode
The following registers have to be programmed before entering Master mode:
1. DADR (+ IADRSZ + IADR if a 10 bit device is addressed): The device address is used to access slave
devices in read or write mode.
2. CKDIV + CHDIV + CLDIV: Clock Waveform.
3. SVDIS: Disable the slave mode.
4. MSEN: Enable the master mode.
33.8.4 Master Transmitter Mode
After the master initiates a Start condition when writing into the Transmit Holding Register, TWI_THR, it sends a 7-
bit slave address, configured in the Master Mode register (DADR in TWI_MMR), to notify the slave device. The bit
following the slave address indicates the transfer direction, 0 in this case (MREAD = 0 in TWI_MMR).
The TWI transfers require the slave to acknowledge each received byte. During the acknowledge clock pulse (9th
pulse), the master releases the data line (HIGH), enabling the slave to pull it down in order to generate the
acknowledge. The master polls the data line during this clock pulse and sets the Not Acknowledge bit (NACK) in
the status register if the slave does not acknowledge the byte. As with the other status bits, an interrupt can be
generated if enabled in the interrupt enable register (TWI_IER). If the slave acknowledges the byte, the data
written in the TWI_THR, is then shifted in the internal shifter and transferred. When an acknowledge is detected,
the TXRDY bit is set until a new write in the TWI_THR.
TXRDY is used as Transmit Ready for the PDC transmit channel.
Host with
TWI
Interface
TWD
TWCK
Atmel TWI
Serial EEPROM I²C RTC I²C LCD
Controller
Slave 1 Slave 2 Slave 3
VDD
I²C Temp.
Sensor
Slave 4
Rp: Pull up value as given by the I²C Standard
Rp Rp
DCXDO—O W :::::::::::::::: :11 FIZZZZZZZZZZZZZZZZZZZ T 1* r K |_| / \ AtmeL
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While no new data is written in the TWI_THR, the Serial Clock Line is tied low. When new data is written in the
TWI_THR, the SCL is released and the data is sent. To generate a STOP event, the STOP command must be
performed by writing in the STOP field of TWI_CR.
After a Master Write transfer, the Serial Clock line is stretched (tied low) while no new data is written in the
TWI_THR or until a STOP command is performed.
See Figure 33-6, Figure 33-7, and Figure 33-8.
Figure 33-6. Master Write with One Data Byte
Figure 33-7. Master Write with Multiple Data Bytes
TXCOMP
TXRDY
Write THR (DATA)
STOP Command sent (write in TWI_CR)
TWD A DATA ASDADR W P
A DATA n ASDADR W DATA n+1 A PDATA n+2 A
TXCOMP
TXRDY
Write THR (Data n)
Write THR (Data n+1) Write THR (Data n+2)
Last data sent
STOP command performed
(by writing in the TWI_CR)
TWD
TWCK
\ mm W ::::::::::::::::::::: I‘I::::::::::::::::: 1~ r L L |_l / \ X:X:><:>CX:>C><:x ‘ig—f="" 7‘="" atmel="">
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Figure 33-8. Master Write with One Byte Internal Address and Multiple Data Bytes
33.8.5 Master Receiver Mode
The read sequence begins by setting the START bit. After the start condition has been sent, the master sends a 7-
bit slave address to notify the slave device. The bit following the slave address indicates the transfer direction, 1 in
this case (MREAD = 1 in TWI_MMR). During the acknowledge clock pulse (9th pulse), the master releases the
data line (HIGH), enabling the slave to pull it down in order to generate the acknowledge. The master polls the
data line during this clock pulse and sets the NACK bit in the status register if the slave does not acknowledge the
byte.
If an acknowledge is received, the master is then ready to receive data from the slave. After data has been
received, the master sends an acknowledge condition to notify the slave that the data has been received except
for the last data, after the stop condition. See Figure 33-9. When the RXRDY bit is set in the status register, a
character has been received in the receive-holding register (TWI_RHR). The RXRDY bit is reset when reading the
TWI_RHR.
When a single data byte read is performed, with or without internal address (IADR), the START and STOP bits
must be set at the same time. See Figure 33-9. When a multiple data byte read is performed, with or without
internal address (IADR), the STOP bit must be set after the next-to-last data received. See Figure 33-10. For
Internal Address usage see Section 33.8.6.
Figure 33-9. Master Read with One Data Byte
A DATA n ASDADR W DATA n+1 A PDATA n+2 A
TXCOMP
TXRDY
Write THR (Data n)
Write THR (Data n+1) Write THR (Data n+2)
Last data sent
STOP command performed
(by writing in the TWI_CR)
TWD IADR A
TWCK
ASDADR R DATA N P
TXCOMP
Write START &
STOP Bit
RXRDY
Read RHR
TWD
‘f‘figgfixmfix _|\
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Figure 33-10. Master Read with Multiple Data Bytes
RXRDY is used as Receive Ready for the PDC receive channel.
33.8.6 Internal Address
The TWI interface can perform various transfer formats: Transfers with 7-bit slave address devices and 10-bit
slave address devices.
33.8.6.1 7-bit Slave Addressing
When Addressing 7-bit slave devices, the internal address bytes are used to perform random address (read or
write) accesses to reach one or more data bytes, within a memory page location in a serial memory, for example.
When performing read operations with an internal address, the TWI performs a write operation to set the internal
address into the slave device, and then switch to Master Receiver mode. Note that the second start condition (after
sending the IADR) is sometimes called “repeated start” (Sr) in I2C fully-compatible devices. See Figure 33-12. See
Figure 33-11 and Figure 33-13 for Master Write operation with internal address.
The three internal address bytes are configurable through the Master Mode register (TWI_MMR).
If the slave device supports only a 7-bit address, i.e. no internal address, IADRSZ must be set to 0.
In the figures below the following abbreviations are used:
N
ASDADR R DATA n A ADATA (n+1) A DATA (n+m)DATA (n+m)-1 PTWD
TXCOMP
Write START Bit
RXRDY
Write STOP Bit
after next-to-last data read
Read RHR
DATA n Read RHR
DATA (n+1) Read RHR
DATA (n+m)-1 Read RHR
DATA (n+m)
SStart
Sr Repeated Start
PStop
WWrite
RRead
AAcknowledge
NNot Acknowledge
DADR Device Address
IADR Internal Address
WOOUW Example: Address a 107bit device AtmeL
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Figure 33-11. Master Write with One, Two or Three Bytes Internal Address and One Data Byte
Figure 33-12. Master Read with One, Two or Three Bytes Internal Address and One Data Byte
33.8.6.2 10-bit Slave Addressing
For a slave address higher than 7 bits, the user must configure the address size (IADRSZ) and set the other slave
address bits in the internal address register (TWI_IADR). The two remaining Internal address bytes, IADR[15:8]
and IADR[23:16] can be used the same as in 7-bit Slave Addressing.
Example: Address a 10-bit device (10-bit device address is b1 b2 b3 b4 b5 b6 b7 b8 b9 b10)
1. Program IADRSZ = 1,
2. Program DADR with 1 1 1 1 0 b1 b2 (b1 is the MSB of the 10-bit address, b2, etc.)
3. Program TWI_IADR with b3 b4 b5 b6 b7 b8 b9 b10 (b10 is the LSB of the 10-bit address)
Figure 33-13 below shows a byte write to an Atmel AT24LC512 EEPROM. This demonstrates the use of internal
addresses to access the device.
Figure 33-13. Internal Address Usage
SDADR W A IADR(23:16) A IADR(15:8) A IADR(7:0) A DATA A P
SDADR W A IADR(15:8) A IADR(7:0) A P
DATA A
A IADR(7:0) A P
DATA ASDADR W
TWD
Three bytes internal address
Two bytes internal address
One byte internal address
TWD
TWD
SDADR WA IADR(23:16) A IADR(15:8)AIADR(7:0) A
SDADR W A IADR(15:8)A IADR(7:0) A
AIADR(7:0) A
SDADR W
DATA N P
Sr DADR R A
Sr DADR R A DATA N P
SrDADR RA DATA NP
TWD
TWD
TWD
Three bytes internal address
Two bytes internal address
One byte internal address
S
T
A
R
T
M
S
B
Device
Address
0
L
S
B
R
/
W
A
C
K
M
S
B
W
R
I
T
E
A
C
K
A
C
K
L
S
B
A
C
K
FIRST
WORD ADDRESS SECOND
WORD ADDRESS DATA
S
T
O
P
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33.8.7 Using the Peripheral DMA Controller (PDC)
The use of the PDC significantly reduces the CPU load.
To assure correct implementation, respect the following programming sequences:
33.8.7.1 Data Transmit with the PDC
1. Initialize the transmit PDC (memory pointers, size, etc.).
2. Configure the master mode (DADR, CKDIV, etc.).
3. Start the transfer by setting the PDC TXTEN bit.
4. Wait for the PDC end TX flag.
5. Disable the PDC by setting the PDC TXDIS bit.
33.8.7.2 Data Receive with the PDC
1. Initialize the receive PDC (memory pointers, size - 1, etc.).
2. Configure the master mode (DADR, CKDIV, etc.).
3. Start the transfer by setting the PDC RXTEN bit.
4. Wait for the PDC end RX flag.
5. Disable the PDC by setting the PDC RXDIS bit.
33.8.8 SMBUS Quick Command (Master Mode Only)
The TWI interface can perform a Quick Command:
1. Configure the master mode (DADR, CKDIV, etc.).
2. Write the MREAD bit in the TWI_MMR register at the value of the one-bit command to be sent.
3. Start the transfer by setting the QUICK bit in the TWI_CR.
Figure 33-14. SMBUS Quick Command
33.8.9 Read-write Flowcharts
The following flowcharts shown in Figure 33-16 on page 720, Figure 33-17 on page 721, Figure 33-18 on page
722, Figure 33-19 on page 723 and Figure 33-20 on page 724 give examples for read and write operations. A
polling or interrupt method can be used to check the status bits. The interrupt method requires that the interrupt
enable register (TWI_IER) be configured first.
TXCOMP
TXRDY
Write QUICK command in TWI_CR
TWD AS DADR R/W P
AtmeL
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Figure 33-15. TWI Write Operation with Single Data Byte without Internal Address
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
Set the Control register:
- Master enable
TWI_CR = MSEN + SVDIS
Set the Master Mode register:
- Device slave address (DADR)
- Transfer direction bit
Write ==> bit MREAD = 0
Load Transmit register
TWI_THR = Data to send
Read Status register
TXRDY = 1?
Read Status register
TXCOMP = 1?
Transfer finished
Yes
Yes
BEGIN
No
No
Write STOP Command
TWI_CR = STOP
SAM3X / SAM3A [DATASHEET]
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720
Figure 33-16. TWI Write Operation with Single Data Byte and Internal Address
BEGIN
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
Set the Control register:
- Master enable
TWI_CR = MSEN + SVDIS
Set the Master Mode register:
- Device slave address (DADR)
- Internal address size (IADRSZ)
- Transfer direction bit
Write ==> bit MREAD = 0
Load transmit register
TWI_THR = Data to send
Read Status register
TXRDY = 1?
Read Status register
TXCOMP = 1?
Transfer finished
Set the internal address
TWI_IADR = address
Yes
Yes
No
No
Write STOP command
TWI_CR = STOP
AAAAA
721
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Figure 33-17. TWI Write Operation with Multiple Data Bytes with or without Internal Address
Set the Control register:
- Master enable
TWI_CR = MSEN + SVDIS
Set the Master Mode register:
- Device slave address
- Internal address size (if IADR used)
- Transfer direction bit
Write ==> bit MREAD = 0
Internal address size = 0?
Load Transmit register
TWI_THR = Data to send
Read Status register
TXRDY = 1?
Data to send?
Read Status register
TXCOMP = 1?
END
BEGIN
Set the internal address
TWI_IADR = address
Yes
TWI_THR = data to send
Yes
Yes
Yes
No
No
No
Write STOP Command
TWI_CR = STOP
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
AAAAA
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722
Figure 33-18. TWI Read Operation with Single Data Byte without Internal Address
Set the Control register:
- Master enable
TWI_CR = MSEN + SVDIS
Set the Master Mode register:
- Device slave address
- Transfer direction bit
Read ==> bit MREAD = 1
Start the transfer
TWI_CR = START | STOP
Read status register
RXRDY = 1?
Read Status register
TXCOMP = 1?
END
BEGIN
Yes
Yes
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
Read Receive Holding Register
No
No
AtmeL
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Figure 33-19. TWI Read Operation with Single Data Byte and Internal Address
Set the Control register:
- Master enable
TWI_CR = MSEN + SVDIS
Set the Master Mode register:
- Device slave address
- Internal address size (IADRSZ)
- Transfer direction bit
Read ==> bit MREAD = 1
Read Status register
TXCOMP = 1?
END
BEGIN
Yes
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
Yes
Set the internal address
TWI_IADR = address
Start the transfer
TWI_CR = START | STOP
Read Status register
RXRDY = 1?
Read Receive Holding register
No
No
AAAAA
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724
Figure 33-20. TWI Read Operation with Multiple Data Bytes with or without Internal Address
Internal address size = 0?
Start the transfer
TWI_CR = START
Stop the transfer
TWI_CR = STOP
Read Status register
RXRDY = 1?
Last data to read
but one?
Read status register
TXCOMP = 1?
END
Set the internal address
TWI_IADR = address
Yes
Yes
Yes
No
Yes
Read Receive Holding register (TWI_RHR)
No
Set the Control register:
- Master enable
TWI_CR = MSEN + SVDIS
Set the Master Mode register:
- Device slave address
- Internal address size (if IADR used)
- Transfer direction bit
Read ==> bit MREAD = 1
BEGIN
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
No
Read Status register
RXRDY = 1?
Yes
Read Receive Holding register (TWI_RHR)
No
AtmeL
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33.9 Multi-master Mode
33.9.1 Definition
More than one master may handle the bus at the same time without data corruption by using arbitration.
Arbitration starts as soon as two or more masters place information on the bus at the same time, and stops
(arbitration is lost) for the master that intends to send a logical one while the other master sends a logical zero.
As soon as arbitration is lost by a master, it stops sending data and listens to the bus in order to detect a stop.
When the stop is detected, the master who has lost arbitration may put its data on the bus by respecting
arbitration.
Arbitration is illustrated in Figure 33-22 on page 726.
33.9.2 Different Multi-master Modes
Two multi-master modes may be distinguished:
1. TWI is considered as a Master only and will never be addressed.
2. TWI may be either a Master or a Slave and may be addressed.
Note: In both Multi-master modes arbitration is supported.
33.9.2.1 TWI as Master Only
In this mode, TWI is considered as a Master only (MSEN is always at one) and must be driven like a Master with
the ARBLST (ARBitration Lost) flag in addition.
If arbitration is lost (ARBLST = 1), the programmer must reinitiate the data transfer.
If the user starts a transfer (ex.: DADR + START + W + Write in THR) and if the bus is busy, the TWI automatically
waits for a STOP condition on the bus to initiate the transfer (see Figure 33-21 on page 726).
Note: The state of the bus (busy or free) is not indicated in the user interface.
33.9.2.2 TWI as Master or Slave
The automatic reversal from Master to Slave is not supported in case of a lost arbitration.
Then, in the case where TWI may be either a Master or a Slave, the programmer must manage the pseudo Multi-
master mode described in the steps below.
1. Program TWI in Slave mode (SADR + MSDIS + SVEN) and perform Slave Access (if TWI is addressed).
2. If TWI has to be set in Master mode, wait until TXCOMP flag is at 1.
3. Program Master mode (DADR + SVDIS + MSEN) and start the transfer (ex: START + Write in THR).
4. As soon as the Master mode is enabled, TWI scans the bus in order to detect if it is busy or free. When the
bus is considered as free, TWI initiates the transfer.
5. As soon as the transfer is initiated and until a STOP condition is sent, the arbitration becomes relevant and
the user must monitor the ARBLST flag.
6. If the arbitration is lost (ARBLST is set to 1), the user must program the TWI in Slave mode in the case
where the Master that won the arbitration wanted to access the TWI.
7. If TWI has to be set in Slave mode, wait until TXCOMP flag is at 1 and then program the Slave mode.
Note: In the case where the arbitration is lost and TWI is addressed, TWI will not acknowledge even if it is programmed in
Slave mode as soon as ARBLST is set to 1. Then, the Master must repeat SADR.
ZZZZZZZZZZZZZZZZZ'flflJ—WZ2:22:22:ZZZ: I:IIIIIIIIIIIili—L/ _____________________ ________________ T T AtmeL
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726
Figure 33-21. Programmer Sends Data While the Bus is Busy
Figure 33-22. Arbitration Cases
The flowchart shown in Figure 33-23 on page 727 gives an example of read and write operations in Multi-master
mode.
TWCK
TWD DATA sent by a master
STOP sent by the master START sent by the TWI
DATA sent by the TWI
Bus is busy
Bus is free
A transfer is programmed
(DADR + W + START + Write THR) Transfer is initiated
TWI DATA transfer Transfer is kept
Bus is considered as free
TWCK
Bus is busyBus is free
A transfer is programmed
(DADR + W + START + Write THR) Transfer is initiated
TWI DATA transfer Transfer is kept
Bus is considered as free
Data from a Master
Data from TWI S0
S00
1
1
1
ARBLST
S0
S00
1
1
1
TWD S00
1
11
11
Arbitration is lost
TWI stops sending data
P
S0
1
P0
11
11
Data from the master Data from the TWI
Arbitration is lost
The master stops sending data
Transfer is stopped
Transfer is programmed again
(DADR + W + START + Write THR)
TWCK
TWD
Q I V Read Sums Register Wme m TWI_THR {r Read S‘ams neglsm ARBLST: I 7 Read TWI_RHR Read S‘atus Raglsler TXCOMP = n AtmeL
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SAM3X / SAM3A [DATASHEET]
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Figure 33-23. Multi-master Flowchart
Programm the SLAVE mode:
SADR + MSDIS + SVEN
SVACC = 1 ?
TXCOMP = 1 ?
GACC = 1 ?
Decoding of the
programming sequence
Prog seq
OK ?
Change SADR
SVREAD = 1 ?
Read Status Register
RXRDY= 1 ?
Read TWI_RHR
TXRDY= 1 ?
EOSACC = 1 ?
Write in TWI_THR
Need to perform
a master access ?
Program the Master mode
DADR + SVDIS + MSEN + CLK + R / W
Read Status Register
ARBLST = 1 ?
MREAD = 1 ?
TXRDY= 0 ?
Write in TWI_THR
Data to send ?
RXRDY= 0 ?
Read TWI_RHR Data to read?
Read Status Register
TXCOMP = 0 ?
GENERAL CALL TREATMENT
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Stop Transfer
TWI_CR = STOP
No
No No
No
No
No
No
No
No
No
No
No
No
No No
No
START
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33.10 Slave Mode
33.10.1 Definition
The Slave Mode is defined as a mode where the device receives the clock and the address from another device
called the master.
In this mode, the device never initiates and never completes the transmission (START, REPEATED_START and
STOP conditions are always provided by the master).
33.10.2 Application Block Diagram
Figure 33-24. Slave Mode Typical Application Block Diagram
33.10.3 Programming Slave Mode
The following fields must be programmed before entering Slave mode:
1. SADR (TWI_SMR): The slave device address is used in order to be accessed by master devices in read
or write mode.
2. MSDIS (TWI_CR): Disable the master mode.
3. SVEN (TWI_CR): Enable the slave mode.
As the device receives the clock, values written in TWI_CWGR are not taken into account.
33.10.4 Receiving Data
After a Start or Repeated Start condition is detected and if the address sent by the Master matches with the Slave
address programmed in the SADR (Slave ADdress) field, SVACC (Slave ACCess) flag is set and SVREAD (Slave
READ) indicates the direction of the transfer.
SVACC remains high until a STOP condition or a repeated START is detected. When such a condition is detected,
EOSACC (End Of Slave ACCess) flag is set.
33.10.4.1Read Sequence
In the case of a Read sequence (SVREAD is high), TWI transfers data written in the TWI_THR (TWI Transmit
Holding Register) until a STOP condition or a REPEATED_START + an address different from SADR is detected.
Note that at the end of the read sequence TXCOMP (Transmission Complete) flag is set and SVACC reset.
As soon as data is written in the TWI_THR, TXRDY (Transmit Holding Register Ready) flag is reset, and it is set
when the shift register is empty and the sent data acknowledged or not. If the data is not acknowledged, the NACK
flag is set.
Note that a STOP or a repeated START always follows a NACK.
Host with
TWI
Interface
TWD
TWCK
LCD Controller
Slave 1 Slave 2 Slave 3
RR
VDD
Host with TWI
Interface Host with TWI
Interface
Master
AtmeL
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See Figure 33-25 on page 730.
33.10.4.2Write Sequence
In the case of a Write sequence (SVREAD is low), the RXRDY (Receive Holding Register Ready) flag is set as
soon as a character has been received in the TWI_RHR (TWI Receive Holding Register). RXRDY is reset when
reading the TWI_RHR.
TWI continues receiving data until a STOP condition or a REPEATED_START + an address different from SADR
is detected. Note that at the end of the write sequence TXCOMP flag is set and SVACC reset.
See Figure 33-26 on page 730.
33.10.4.3Clock Synchronization Sequence
In the case where TWI_THR or TWI_RHR is not written/read in time, TWI performs a clock synchronization.
Clock stretching information is given by the SCLWS (Clock Wait state) bit.
See Figure 33-28 on page 731 and Figure 33-29 on page 732.
33.10.4.4General Call
In the case where a GENERAL CALL is performed, GACC (General Call ACCess) flag is set.
After GACC is set, it is up to the programmer to interpret the meaning of the GENERAL CALL and to decode the
new address programming sequence.
See Figure 33-27 on page 731.
33.10.4.5PDC
As it is impossible to know the exact number of data to receive/send, the use of PDC is NOT recommended in
SLAVE mode.
33.10.5 Data Transfer
33.10.5.1Read Operation
The read mode is defined as a data requirement from the master.
After a START or a REPEATED START condition is detected, the decoding of the address starts. If the slave
address (SADR) is decoded, SVACC is set and SVREAD indicates the direction of the transfer.
Until a STOP or REPEATED START condition is detected, TWI continues sending data loaded in the TWI_THR
register.
If a STOP condition or a REPEATED START + an address different from SADR is detected, SVACC is reset.
Figure 33-25 on page 730 describes the write operation.
i l / \ __ —/|—rf:::::|_h—"7iu' AtmeL
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Figure 33-25. Read Access Ordered by a MASTER
Notes: 1. When SVACC is low, the state of SVREAD becomes irrelevant.
2. TXRDY is reset when data has been transmitted from TWI_THR to the shift register and set when this data has been
acknowledged or non acknowledged.
33.10.5.2Write Operation
The write mode is defined as a data transmission from the master.
After a START or a REPEATED START, the decoding of the address starts. If the slave address is decoded,
SVACC is set and SVREAD indicates the direction of the transfer (SVREAD is low in this case).
Until a STOP or REPEATED START condition is detected, TWI stores the received data in the TWI_RHR register.
If a STOP condition or a REPEATED START + an address different from SADR is detected, SVACC is reset.
Figure 33-26 on page 730 describes the Write operation.
Figure 33-26. Write Access Ordered by a Master
Notes: 1. When SVACC is low, the state of SVREAD becomes irrelevant.
2. RXRDY is set when data has been transmitted from the shift register to the TWI_RHR and reset when this data is read.
33.10.5.3General Call
The general call is performed in order to change the address of the slave.
If a GENERAL CALL is detected, GACC is set.
After the detection of General Call, it is up to the programmer to decode the commands which come afterwards.
Write THR Read RHR
SVREAD has to be taken into account only while SVACC is active
TWD
TXRDY
NACK
SVACC
SVREAD
EOSVACC
SADRSADR R NA R A DATA A A DATA NA S/SrDATA NA P/S/Sr
SADR matches,
TWI answers with an ACK
SADR does not match,
TWI answers with a NACK ACK/NACK from the Master
RXRDY
Read RHR
SVREAD has to be taken into account only while SVACC is active
TWD
SVACC
SVREAD
EOSVACC
SADR does not match,
TWI answers with a NACK
SADRSADR W NA W A DATA A A DATA NA S/SrDATA NA P/S/Sr
SADR matches,
TWI answers with an ACK
? mm 3 ; :E L m s». __ o o A U WWWWW C. a /. _O"\ ; WM fi « .m . x WM 9 M :w®oo
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SAM3X / SAM3A [DATASHEET]
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In case of a WRITE command, the programmer has to decode the programming sequence and program a new
SADR if the programming sequence matches.
Figure 33-27 on page 731 describes the General Call access.
Figure 33-27. Master Performs a General Call
Note: This method allows the user to create an own programming sequence by choosing the programming bytes and the
number of them. The programming sequence has to be provided to the master.
33.10.5.4Clock Synchronization
In both read and write modes, it may happen that TWI_THR/TWI_RHR buffer is not filled /emptied before the
emission/reception of a new character. In this case, to avoid sending/receiving undesired data, a clock stretching
mechanism is implemented.
Clock Synchronization in Read Mode
The clock is tied low if the shift register is empty and if a STOP or REPEATED START condition was not detected.
It is tied low until the shift register is loaded.
Figure 33-28 on page 731 describes the clock synchronization in Read mode.
Figure 33-28. Clock Synchronization in Read Mode
Notes: 1. TXRDY is reset when data has been written in the TWI_THR to the shift register and set when this data has been
acknowledged or non acknowledged.
0000000 + W
GENERAL CALL P
SA
GENERAL CALL Reset or write DADD A New SADR
DATA1 A DATA2 A
A
New SADR
Programming sequence
TXD
GCACC
SVACC
RESET command = 00000110X
WRITE command = 00000100X
Reset after read
DATA1
The clock is stretched after the ACK, the state of TWD is undefined during clock stretching
SCLWS
SVACC
SVREAD
TXRDY
TWCK
TWI_THR
TXCOMP
The data is memorized in TWI_THR until a new value is written
TWI_THR is transmitted to the shift register Ack or Nack from the master
DATA0DATA0 DATA2
1
2
1
CLOCK is tied low by the TWI
as long as THR is empty
SSADR
SRDATA0AADATA1 ADATA2 NA S
XXXXXXX
2
Write THR
As soon as a START is detected
1%: ‘Ln _l'|_l'| ./” /flU r--- | F "I
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732
2. At the end of the read sequence, TXCOMP is set after a STOP or after a REPEATED_START + an address different from
SADR.
3. SCLWS is automatically set when the clock synchronization mechanism is started.
Clock Synchronization in Write Mode
The clock is tied low if the shift register and the TWI_RHR is full. If a STOP or REPEATED_START condition was
not detected, it is tied low until TWI_RHR is read.
Figure 33-29 on page 732 describes the clock synchronization in Read mode.
Figure 33-29. Clock Synchronization in Write Mode
Notes: 1. At the end of the read sequence, TXCOMP is set after a STOP or after a REPEATED_START + an address different from
SADR.
2. SCLWS is automatically set when the clock synchronization mechanism is started and automatically reset when the
mechanism is finished.
33.10.5.5Reversal after a Repeated Start
Reversal of Read to Write
The master initiates the communication by a read command and finishes it by a write command.
Figure 33-30 on page 733 describes the repeated start + reversal from Read to Write mode.
Rd DATA0 Rd DATA1 Rd DATA2
SVACC
SVREAD
RXRDY
SCLWS
TXCOMP
DATA1 DATA2
SCL is stretched on the last bit of DATA1
As soon as a START is detected
TWCK
TWD
TWI_RHR
CLOCK is tied low by the TWI as long as RHR is full
DATA0 is not read in the RHR
ADRSSADR W ADATA0A A DATA2DATA1 S
NA
_@ |—|<~ c‘eared="" may="" read="" ,="" d="" ,="" (d="" ,="" \="">®O
733
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Figure 33-30. Repeated Start + Reversal from Read to Write Mode
1. TXCOMP is only set at the end of the transmission because after the repeated start, SADR is detected again.
Reversal of Write to Read
The master initiates the communication by a write command and finishes it by a read command.Figure 33-31 on
page 733 describes the repeated start + reversal from Write to Read mode.
Figure 33-31. Repeated Start + Reversal from Write to Read Mode
Notes: 1. In this case, if TWI_THR has not been written at the end of the read command, the clock is automatically stretched before
the ACK.
2. TXCOMP is only set at the end of the transmission because after the repeated start, SADR is detected again.
33.10.6 Read Write Flowcharts
The flowchart shown in Figure 33-32 on page 734 gives an example of read and write operations in Slave mode. A
polling or interrupt method can be used to check the status bits. The interrupt method requires that the interrupt
enable register (TWI_IER) be configured first.
SSADR R ADATA0A DATA1 SADRSr
NA
W A DATA2 A DATA3AP
Cleared after read
DATA0 DATA1
DATA2 DATA3
SVACC
SVREAD
TWD
TWI_THR
TWI_RHR
EOSACC
TXRDY
RXRDY
TXCOMP
As soon as a START is detected
SSADR W ADATA0A DATA1 SADRSr
A
R A DATA2 A DATA3NA P
Cleared after read
DATA0
DATA2 DATA3
DATA1
TXCOMP
TXRDY
RXRDY
As soon as a START is detected
Read TWI_RHR
SVACC
SVREAD
TWD
TWI_RHR
TWI_THR
EOSACC
START =07 SVHEAD RXRDY: 0 7 Frog seq ves
SAM3X / SAM3A [DATASHEET]
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734
Figure 33-32. Read Write Flowchart in Slave Mode
Set the SLAVE mode:
SADR + MSDIS + SVEN
SVACC = 1 ?
TXCOMP = 1 ?
GACC = 1 ?
Decoding of the
programming sequence
Prog seq
OK ?
Change SADR
SVREAD = 0 ?
Read Status Register
RXRDY= 0 ?
Read TWI_RHR
TXRDY= 1 ?
EOSACC = 1 ?
Write in TWI_THR
END
GENERAL CALL TREATMENT
No
No
No No
No
No
No
No
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33.11 Two-wire Interface (TWI) User Interface
Note: 1. All unlisted offset values are conisedered as “reserved”.
Table 33-6. Register Mapping
Offset Register Name Access Reset
0x00 Control Register TWI_CR Write-only N / A
0x04 Master Mode Register TWI_MMR Read-write 0x00000000
0x08 Slave Mode Register TWI_SMR Read-write 0x00000000
0x0C Internal Address Register TWI_IADR Read-write 0x00000000
0x10 Clock Waveform Generator Register TWI_CWGR Read-write 0x00000000
0x14 - 0x1C Reserved –––
0x20 Status Register TWI_SR Read-only 0x0000F009
0x24 Interrupt Enable Register TWI_IER Write-only N / A
0x28 Interrupt Disable Register TWI_IDR Write-only N / A
0x2C Interrupt Mask Register TWI_IMR Read-only 0x00000000
0x30 Receive Holding Register TWI_RHR Read-only 0x00000000
0x34 Transmit Holding Register TWI_THR Write-only 0x00000000
0xEC - 0xFC(1) Reserved – – –
0x100 - 0x124 Reserved for the PDC – – –
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736
33.11.1 TWI Control Register
Name: TWI_CR
Address: 0x4008C000 (0), 0x40090000 (1)
Access: Write-only
Reset: 0x00000000
• START: Send a START Condition
0 = No effect.
1 = A frame beginning with a START bit is transmitted according to the features defined in the mode register.
This action is necessary when the TWI peripheral wants to read data from a slave. When configured in Master Mode with a
write operation, a frame is sent as soon as the user writes a character in the Transmit Holding Register (TWI_THR).
• STOP: Send a STOP Condition
0 = No effect.
1 = STOP Condition is sent just after completing the current byte transmission in master read mode.
–In single data byte master read, the START and STOP must both be set.
–In multiple data bytes master read, the STOP must be set after the last data received but one.
–In master read mode, if a NACK bit is received, the STOP is automatically performed.
–In master data write operation, a STOP condition will be sent after the transmission of the current data is
finished.
• MSEN: TWI Master Mode Enabled
0 = No effect.
1 = If MSDIS = 0, the master mode is enabled.
Note: Switching from Slave to Master mode is only permitted when TXCOMP = 1.
• MSDIS: TWI Master Mode Disabled
0 = No effect.
1 = The master mode is disabled, all pending data is transmitted. The shifter and holding characters (if it contains data) are
transmitted in case of write operation. In read operation, the character being transferred must be completely received
before disabling.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
SWRST QUICK SVDIS SVEN MSDISMSEN STOP START
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• SVEN: TWI Slave Mode Enabled
0 = No effect.
1 = If SVDIS = 0, the slave mode is enabled.
Note: Switching from Master to Slave mode is only permitted when TXCOMP = 1.
• SVDIS: TWI Slave Mode Disabled
0 = No effect.
1 = The slave mode is disabled. The shifter and holding characters (if it contains data) are transmitted in case of read oper-
ation. In write operation, the character being transferred must be completely received before disabling.
• QUICK: SMBUS Quick Command
0 = No effect.
1 = If Master mode is enabled, a SMBUS Quick Command is sent.
• SWRST: Software Reset
0 = No effect.
1 = Equivalent to a system reset.
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738
33.11.2 TWI Master Mode Register
Name: TWI_MMR
Address: 0x4008C004 (0), 0x40090004 (1)
Access: Read-write
Reset: 0x00000000
• IADRSZ: Internal Device Address Size
• MREAD: Master Read Direction
0 = Master write direction.
1 = Master read direction.
• DADR: Device Address
The device address is used to access slave devices in read or write mode. Those bits are only used in Master mode.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–DADR
15 14 13 12 11 10 9 8
–––MREAD–– IADRSZ
76543210
––––––––
Value Name Description
0 NONE No internal device address
1 1_BYTE One-byte internal device address
2 2_BYTE Two-byte internal device address
3 3_BYTE Three-byte internal device address
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
33.11.3 TWI Slave Mode Register
Name: TWI_SMR
Address: 0x4008C008 (0), 0x40090008 (1)
Access: Read-write
Reset: 0x00000000
• SADR: Slave Address
The slave device address is used in Slave mode in order to be accessed by master devices in read or write mode.
SADR must be programmed before enabling the Slave mode or after a general call. Writes at other times have no effect.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– SADR
15 14 13 12 11 10 9 8
––––––
76543210
––––––––
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740
33.11.4 TWI Internal Address Register
Name: TWI_IADR
Address: 0x4008C00C (0), 0x4009000C (1)
Access: Read-write
Reset: 0x00000000
• IADR: Internal Address
0, 1, 2 or 3 bytes depending on IADRSZ.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
IADR
15 14 13 12 11 10 9 8
IADR
76543210
IADR
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33.11.5 TWI Clock Waveform Generator Register
Name: TWI_CWGR
Address: 0x4008C010 (0), 0x40090010 (1)
Access: Read-write
Reset: 0x00000000
TWI_CWGR is only used in Master mode.
• CLDIV: Clock Low Divider
The SCL low period is defined as follows:
• CHDIV: Clock High Divider
The SCL high period is defined as follows:
• CKDIV: Clock Divider
The CKDIV is used to increase both SCL high and low periods.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CKDIV
15 14 13 12 11 10 9 8
CHDIV
76543210
CLDIV
Tlow CLDIV(2CKDIV
×()4)+TMCK
×=
Thigh CHDIV(2CKDIV
×()4)+TMCK
×=
TXCOMP used in Master mode TXCOMP used in Slave mode TXRDY used in Master mode TXRDY used in Slave mode AtmeL
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742
33.11.6 TWI Status Register
Name: TWI_SR
Address: 0x4008C020 (0), 0x40090020 (1)
Access: Read-only
Reset: 0x0000F009
• TXCOMP: Transmission Completed (automatically set / reset)
TXCOMP used in Master mode:
0 = During the length of the current frame.
1 = When both holding and shifter registers are empty and STOP condition has been sent.
TXCOMP behavior in Master mode can be seen in Figure 33-8 on page 715 and in Figure 33-10 on page 716.
TXCOMP used in Slave mode:
0 = As soon as a Start is detected.
1 = After a Stop or a Repeated Start + an address different from SADR is detected.
TXCOMP behavior in Slave mode can be seen in Figure 33-28 on page 731, Figure 33-29 on page 732, Figure 33-30 on
page 733 and Figure 33-31 on page 733.
• RXRDY: Receive Holding Register Ready (automatically set / reset)
0 = No character has been received since the last TWI_RHR read operation.
1 = A byte has been received in the TWI_RHR since the last read.
RXRDY behavior in Master mode can be seen in Figure 33-10 on page 716.
RXRDY behavior in Slave mode can be seen in Figure 33-26 on page 730, Figure 33-29 on page 732, Figure 33-30 on
page 733 and Figure 33-31 on page 733.
• TXRDY: Transmit Holding Register Ready (automatically set / reset)
TXRDY used in Master mode:
0 = The transmit holding register has not been transferred into shift register. Set to 0 when writing into TWI_THR register.
1 = As soon as a data byte is transferred from TWI_THR to internal shifter or if a NACK error is detected, TXRDY is set at
the same time as TXCOMP and NACK. TXRDY is also set when MSEN is set (enable TWI).
TXRDY behavior in Master mode can be seen in Figure 33-8 on page 715.
TXRDY used in Slave mode:
0 = As soon as data is written in the TWI_THR, until this data has been transmitted and acknowledged (ACK or NACK).
1 = It indicates that the TWI_THR is empty and that data has been transmitted and acknowledged.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TXBUFE RXBUFF ENDTX ENDRX EOSACC SCLWS ARBLST NACK
76543210
–OVREGACC SVACC SVREAD TXRDY RXRDY TXCOMP
NACK used in Master mode NACK used in Slave Read mode AtmeL
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
If TXRDY is high and if a NACK has been detected, the transmission will be stopped. Thus when TRDY = NACK = 1, the
programmer must not fill TWI_THR to avoid losing it.
TXRDY behavior in Slave mode can be seen in Figure 33-25 on page 730, Figure 33-28 on page 731, Figure 33-30 on
page 733 and Figure 33-31 on page 733.
• SVREAD: Slave Read (automatically set / reset)
This bit is only used in Slave mode. When SVACC is low (no Slave access has been detected) SVREAD is irrelevant.
0 = Indicates that a write access is performed by a Master.
1 = Indicates that a read access is performed by a Master.
SVREAD behavior can be seen in Figure 33-25 on page 730, Figure 33-26 on page 730, Figure 33-30 on page 733 and
Figure 33-31 on page 733.
• SVACC: Slave Access (automatically set / reset)
This bit is only used in Slave mode.
0 = TWI is not addressed. SVACC is automatically cleared after a NACK or a STOP condition is detected.
1 = Indicates that the address decoding sequence has matched (A Master has sent SADR). SVACC remains high until a
NACK or a STOP condition is detected.
SVACC behavior can be seen in Figure 33-25 on page 730, Figure 33-26 on page 730, Figure 33-30 on page 733 and Fig-
ure 33-31 on page 733.
• GACC: General Call Access (clear on read)
This bit is only used in Slave mode.
0 = No General Call has been detected.
1 = A General Call has been detected. After the detection of General Call, if need be, the programmer may acknowledge
this access and decode the following bytes and respond according to the value of the bytes.
GACC behavior can be seen in Figure 33-27 on page 731.
• OVRE: Overrun Error (clear on read)
This bit is only used in Master mode.
0 = TWI_RHR has not been loaded while RXRDY was set
1 = TWI_RHR has been loaded while RXRDY was set. Reset by read in TWI_SR when TXCOMP is set.
• NACK: Not Acknowledged (clear on read)
NACK used in Master mode:
0 = Each data byte has been correctly received by the far-end side TWI slave component.
1 = A data byte has not been acknowledged by the slave component. Set at the same time as TXCOMP.
NACK used in Slave Read mode:
0 = Each data byte has been correctly received by the Master.
1 = In read mode, a data byte has not been acknowledged by the Master. When NACK is set the programmer must not fill
TWI_THR even if TXRDY is set, because it means that the Master will stop the data transfer or re initiate it.
Note that in Slave Write mode all data are acknowledged by the TWI.
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• ARBLST: Arbitration Lost (clear on read)
This bit is only used in Master mode.
0: Arbitration won.
1: Arbitration lost. Another master of the TWI bus has won the multi-master arbitration. TXCOMP is set at the same time.
• SCLWS: Clock Wait State (automatically set / reset)
This bit is only used in Slave mode.
0 = The clock is not stretched.
1 = The clock is stretched. TWI_THR / TWI_RHR buffer is not filled / emptied before the emission / reception of a new
character.
SCLWS behavior can be seen in Figure 33-28 on page 731 and Figure 33-29 on page 732.
• EOSACC: End Of Slave Access (clear on read)
This bit is only used in Slave mode.
0 = A slave access is being performing.
1 = The Slave Access is finished. End Of Slave Access is automatically set as soon as SVACC is reset.
EOSACC behavior can be seen in Figure 33-30 on page 733 and Figure 33-31 on page 733
• ENDRX: End of RX buffer
This bit is only used in Master mode.
0 = The Receive Counter Register has not reached 0 since the last write in TWI_RCR or TWI_RNCR.
1 = The Receive Counter Register has reached 0 since the last write in TWI_RCR or TWI_RNCR.
• ENDTX: End of TX buffer
This bit is only used in Master mode.
0 = The Transmit Counter Register has not reached 0 since the last write in TWI_TCR or TWI_TNCR.
1 = The Transmit Counter Register has reached 0 since the last write in TWI_TCR or TWI_TNCR.
• RXBUFF: RX Buffer Full
This bit is only used in Master mode.
0 = TWI_RCR or TWI_RNCR have a value other than 0.
1 = Both TWI_RCR and TWI_RNCR have a value of 0.
• TXBUFE: TX Buffer Empty
This bit is only used in Master mode.
0 = TWI_TCR or TWI_TNCR have a value other than 0.
1 = Both TWI_TCR and TWI_TNCR have a value of 0.
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33.11.7 TWI Interrupt Enable Register
Name: TWI_IER
Address: 0x4008C024 (0), 0x40090024 (1)
Access: Write-only
Reset: 0x00000000
• TXCOMP: Transmission Completed Interrupt Enable
• RXRDY: Receive Holding Register Ready Interrupt Enable
• TXRDY: Transmit Holding Register Ready Interrupt Enable
• SVACC: Slave Access Interrupt Enable
• GACC: General Call Access Interrupt Enable
• OVRE: Overrun Error Interrupt Enable
• NACK: Not Acknowledge Interrupt Enable
• ARBLST: Arbitration Lost Interrupt Enable
• SCL_WS: Clock Wait State Interrupt Enable
• EOSACC: End Of Slave Access Interrupt Enable
• ENDRX: End of Receive Buffer Interrupt Enable
• ENDTX: End of Transmit Buffer Interrupt Enable
• RXBUFF: Receive Buffer Full Interrupt Enable
• TXBUFE: Transmit Buffer Empty Interrupt Enable
0 = No effect.
1 = Enables the corresponding interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TXBUFE RXBUFF ENDTX ENDRX EOSACC SCL_WS ARBLST NACK
76543210
–OVREGACC SVACC – TXRDY RXRDY TXCOMP
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746
33.11.8 TWI Interrupt Disable Register
Name: TWI_IDR
Address: 0x4008C028 (0), 0x40090028 (1)
Access: Write-only
Reset: 0x00000000
• TXCOMP: Transmission Completed Interrupt Disable
• RXRDY: Receive Holding Register Ready Interrupt Disable
• TXRDY: Transmit Holding Register Ready Interrupt Disable
• SVACC: Slave Access Interrupt Disable
• GACC: General Call Access Interrupt Disable
• OVRE: Overrun Error Interrupt Disable
• NACK: Not Acknowledge Interrupt Disable
• ARBLST: Arbitration Lost Interrupt Disable
• SCL_WS: Clock Wait State Interrupt Disable
• EOSACC: End Of Slave Access Interrupt Disable
• ENDRX: End of Receive Buffer Interrupt Disable
• ENDTX: End of Transmit Buffer Interrupt Disable
• RXBUFF: Receive Buffer Full Interrupt Disable
• TXBUFE: Transmit Buffer Empty Interrupt Disable
0 = No effect.
1 = Disables the corresponding interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TXBUFE RXBUFF ENDTX ENDRX EOSACC SCL_WS ARBLST NACK
76543210
–OVREGACC SVACC – TXRDY RXRDY TXCOMP
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
33.11.9 TWI Interrupt Mask Register
Name: TWI_IMR
Address: 0x4008C02C (0), 0x4009002C (1)
Access: Read-only
Reset: 0x00000000
• TXCOMP: Transmission Completed Interrupt Mask
• RXRDY: Receive Holding Register Ready Interrupt Mask
• TXRDY: Transmit Holding Register Ready Interrupt Mask
• SVACC: Slave Access Interrupt Mask
• GACC: General Call Access Interrupt Mask
• OVRE: Overrun Error Interrupt Mask
• NACK: Not Acknowledge Interrupt Mask
• ARBLST: Arbitration Lost Interrupt Mask
• SCL_WS: Clock Wait State Interrupt Mask
• EOSACC: End Of Slave Access Interrupt Mask
• ENDRX: End of Receive Buffer Interrupt Mask
• ENDTX: End of Transmit Buffer Interrupt Mask
• RXBUFF: Receive Buffer Full Interrupt Mask
• TXBUFE: Transmit Buffer Empty Interrupt Mask
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TXBUFE RXBUFF ENDTX ENDRX EOSACC SCL_WS ARBLST NACK
76543210
–OVREGACC SVACC – TXRDY RXRDY TXCOMP
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33.11.10TWI Receive Holding Register
Name: TWI_RHR
Address: 0x4008C030 (0), 0x40090030 (1)
Access: Read-only
Reset: 0x00000000
• RXDATA: Master or Slave Receive Holding Data
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
RXDATA
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33.11.11TWI Transmit Holding Register
Name: TWI_THR
Address: 0x4008C034 (0), 0x40090034 (1)
Access: Read-write
Reset: 0x00000000
• TXDATA: Master or Slave Transmit Holding Data
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
TXDATA
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750
34. Universal Asynchronous Receiver Transceiver (UART)
34.1 Description
The Universal Asynchronous Receiver Transmitter features a two-pin UART that can be used for communication
and trace purposes and offers an ideal medium for in-situ programming solutions. Moreover, the association with
two peripheral DMA controller (PDC) channels permits packet handling for these tasks with processor time
reduced to a minimum.
34.2 Embedded Characteristics
Two-pin UART
̶Implemented Features are USART Compatible
̶Independent Receiver and Transmitter with a Common Programmable Baud Rate Generator
̶Even, Odd, Mark or Space Parity Generation
̶Parity, Framing and Overrun Error Detection
̶Automatic Echo, Local Loopback and Remote Loopback Channel Modes
̶Interrupt Generation
̶Support for Two PDC Channels with Connection to Receiver and Transmitter
¢ ¢ D D AtmeL
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34.3 Block Diagram
Figure 34-1. UART Functional Block Diagram
34.4 Product Dependencies
34.4.1 I/O Lines
The UART pins are multiplexed with PIO lines. The programmer must first configure the corresponding PIO
Controller to enable I/O line operations of the UART.
34.4.2 Power Management
The UART clock is controllable through the Power Management Controller. In this case, the programmer must first
configure the PMC to enable the UART clock. Usually, the peripheral identifier used for this purpose is 1.
34.4.3 Interrupt Source
The UART interrupt line is connected to one of the interrupt sources of the Nested Vectored Interrupt Controller
(NVIC). Interrupt handling requires programming of the NVIC before configuring the UART.
Peripheral DMA Controller
Baud Rate
Generator
Transmit
Receive
Interrupt
Control
Peripheral
Bridge
Parallel
Input/
Output
UTXD
URXD
Power
Management
Controller
MCK
uart_irq
APB UART
Table 34-1. UART Pin Description
Pin Name Description Type
URXD UART Receive Data Input
UTXD UART Transmit Data Output
Table 34-2. I/O Lines
Instance Signal I/O Line Peripheral
UART URXD PA8 A
UART UTXD PA9 A
supports only itter that opera guard are not ART. clock named b 16 times the va baud rate cloc divided by 16 AtmeL
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752
34.5 UART Operations
The UART operates in asynchronous mode only and supports only 8-bit character handling (with parity). It has no
clock pin.
The UART is made up of a receiver and a transmitter that operate independently, and a common baud rate
generator. Receiver timeout and transmitter time guard are not implemented. However, all the implemented
features are compatible with those of a standard USART.
34.5.1 Baud Rate Generator
The baud rate generator provides the bit period clock named baud rate clock to both the receiver and the
transmitter.
The baud rate clock is the master clock divided by 16 times the value (CD) written in UART_BRGR (Baud Rate
Generator Register). If UART_BRGR is set to 0, the baud rate clock is disabled and the UART remains inactive.
The maximum allowable baud rate is Master Clock divided by 16. The minimum allowable baud rate is Master
Clock divided by (16 x 65536).
Figure 34-2. Baud Rate Generator
34.5.2 Receiver
34.5.2.1 Receiver Reset, Enable and Disable
After device reset, the UART receiver is disabled and must be enabled before being used. The receiver can be
enabled by writing the control register UART_CR with the bit RXEN at 1. At this command, the receiver starts
looking for a start bit.
The programmer can disable the receiver by writing UART_CR with the bit RXDIS at 1. If the receiver is waiting for
a start bit, it is immediately stopped. However, if the receiver has already detected a start bit and is receiving the
data, it waits for the stop bit before actually stopping its operation.
The programmer can also put the receiver in its reset state by writing UART_CR with the bit RSTRX at 1. In doing
so, the receiver immediately stops its current operations and is disabled, whatever its current state. If RSTRX is
applied when data is being processed, this data is lost.
Baud Rate MCK
16 CD ×
---------------------- =
MCK 16-bit Counter
0
Baud Rate
Clock
CD
CD
OUT
Divide
by 16
0
1
>1
Receiver
Sampling Cloc
k
‘I i i ‘ a HHTHI 3 3 3 3 I ‘ ‘ j r AtmeL
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34.5.2.2 Start Detection and Data Sampling
The UART only supports asynchronous operations, and this affects only its receiver. The UART receiver detects
the start of a received character by sampling the URXD signal until it detects a valid start bit. A low level (space) on
URXD is interpreted as a valid start bit if it is detected for more than 7 cycles of the sampling clock, which is 16
times the baud rate. Hence, a space that is longer than 7/16 of the bit period is detected as a valid start bit. A
space which is 7/16 of a bit period or shorter is ignored and the receiver continues to wait for a valid start bit.
When a valid start bit has been detected, the receiver samples the URXD at the theoretical midpoint of each bit. It
is assumed that each bit lasts 16 cycles of the sampling clock (1-bit period) so the bit sampling point is eight cycles
(0.5-bit period) after the start of the bit. The first sampling point is therefore 24 cycles (1.5-bit periods) after the
falling edge of the start bit was detected.
Each subsequent bit is sampled 16 cycles (1-bit period) after the previous one.
Figure 34-3. Start Bit Detection
Figure 34-4. Character Reception
34.5.2.3 Receiver Ready
When a complete character is received, it is transferred to the UART_RHR and the RXRDY status bit in UART_SR
(Status Register) is set. The bit RXRDY is automatically cleared when the receive holding register UART_RHR is
read.
Figure 34-5. Receiver Ready
Sampling Clock
URXD
True Start
Detection D0
Baud Rate
Clock
D0 D1 D2 D3D4 D5 D6 D7
URXD
True Start Detection
Sampling
Parity Bit
Stop Bit
Example: 8-bit, parity enabled 1 stop
1 bit
period
0.5 bit
period
D0 D1 D2 D3D4 D5 D6 D7 PSSD0 D1 D2 D3D4 D5 D6 D7 P
URXD
Read UART_RHR
RXRDY
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34.5.2.4 Receiver Overrun
If UART_RHR has not been read by the software (or the Peripheral Data Controller or DMA Controller) since the
last transfer, the RXRDY bit is still set and a new character is received, the OVRE status bit in UART_SR is set.
OVRE is cleared when the software writes the control register UART_CR with the bit RSTSTA (Reset Status) at 1.
Figure 34-6. Receiver Overrun
34.5.2.5 Parity Error
Each time a character is received, the receiver calculates the parity of the received data bits, in accordance with
the field PAR in UART_MR. It then compares the result with the received parity bit. If different, the parity error bit
PARE in UART_SR is set at the same time the RXRDY is set. The parity bit is cleared when the control register
UART_CR is written with the bit RSTSTA (Reset Status) at 1. If a new character is received before the reset status
command is written, the PARE bit remains at 1.
Figure 34-7. Parity Error
34.5.2.6 Receiver Framing Error
When a start bit is detected, it generates a character reception when all the data bits have been sampled. The stop
bit is also sampled and when it is detected at 0, the FRAME (Framing Error) bit in UART_SR is set at the same
time the RXRDY bit is set. The FRAME bit remains high until the control register UART_CR is written with the bit
RSTSTA at 1.
Figure 34-8. Receiver Framing Error
D0 D1 D2 D3D4 D5 D6 D7 PSSD0 D1 D2 D3D4 D5 D6 D7 P
URXD
RSTSTA
RXRDY
OVRE
stop stop
stop
D0 D1 D2 D3D4 D5 D6 D7 PS
URXD
RSTSTA
RXRDY
PARE
Wrong Parity Bit
D0 D1 D2 D3D4 D5 D6 D7 PS
URXD
RSTSTA
RXRDY
FRAME
Stop Bit
Detected at 0
stop
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34.5.3 Transmitter
34.5.3.1 Transmitter Reset, Enable and Disable
After device reset, the UART transmitter is disabled and it must be enabled before being used. The transmitter is
enabled by writing the control register UART_CR with the bit TXEN at 1. From this command, the transmitter waits
for a character to be written in the Transmit Holding Register (UART_THR) before actually starting the
transmission.
The programmer can disable the transmitter by writing UART_CR with the bit TXDIS at 1. If the transmitter is not
operating, it is immediately stopped. However, if a character is being processed into the Shift Register and/or a
character has been written in the Transmit Holding Register, the characters are completed before the transmitter is
actually stopped.
The programmer can also put the transmitter in its reset state by writing the UART_CR with the bit RSTTX at 1.
This immediately stops the transmitter, whether or not it is processing characters.
34.5.3.2 Transmit Format
The UART transmitter drives the pin UTXD at the baud rate clock speed. The line is driven depending on the
format defined in the Mode Register and the data stored in the Shift Register. One start bit at level 0, then the 8
data bits, from the lowest to the highest bit, one optional parity bit and one stop bit at 1 are consecutively shifted
out as shown in the following figure. The field PARE in the mode register UART_MR defines whether or not a
parity bit is shifted out. When a parity bit is enabled, it can be selected between an odd parity, an even parity, or a
fixed space or mark bit.
Figure 34-9. Character Transmission
34.5.3.3 Transmitter Control
When the transmitter is enabled, the bit TXRDY (Transmitter Ready) is set in the status register UART_SR. The
transmission starts when the programmer writes in the Transmit Holding Register (UART_THR), and after the
written character is transferred from UART_THR to the Shift Register. The TXRDY bit remains high until a second
character is written in UART_THR. As soon as the first character is completed, the last character written in
UART_THR is transferred into the shift register and TXRDY rises again, showing that the holding register is empty.
When both the Shift Register and UART_THR are empty, i.e., all the characters written in UART_THR have been
processed, the TXEMPTY bit rises after the last stop bit has been completed.
D0 D1 D2 D3D4 D5 D6 D7
UTXD
Start
Bit Parity
Bit Stop
Bit
Example: Parity enabled
Baud Rate
Clock
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Figure 34-10. Transmitter Control
34.5.4 Peripheral DMA Controller
Both the receiver and the transmitter of the UART are connected to a Peripheral DMA Controller (PDC) channel.
The peripheral data controller channels are programmed via registers that are mapped within the UART user
interface from the offset 0x100. The status bits are reported in the UART status register (UART_SR) and can
generate an interrupt.
The RXRDY bit triggers the PDC channel data transfer of the receiver. This results in a read of the data in
UART_RHR. The TXRDY bit triggers the PDC channel data transfer of the transmitter. This results in a write of
data in UART_THR.
UART_THR
Shift Register
UTXD
TXRDY
TXEMPTY
Data 0Data 1
Data 0
Data 0
Data 1
Data 1SSPP
Write Data 0
in UART_THR Write Data 1
in UART_THR
stop
stop
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34.5.5 Test Modes
The UART supports three test modes. These modes of operation are programmed by using the field CHMODE
(Channel Mode) in the mode register (UART_MR).
The Automatic Echo mode allows bit-by-bit retransmission. When a bit is received on the URXD line, it is sent to
the UTXD line. The transmitter operates normally, but has no effect on the UTXD line.
The Local Loopback mode allows the transmitted characters to be received. UTXD and URXD pins are not used
and the output of the transmitter is internally connected to the input of the receiver. The URXD pin level has no
effect and the UTXD line is held high, as in idle state.
The Remote Loopback mode directly connects the URXD pin to the UTXD line. The transmitter and the receiver
are disabled and have no effect. This mode allows a bit-by-bit retransmission.
Figure 34-11. Test Modes
Receiver
Transmitter Disabled
RXD
TXD
Receiver
Transmitter Disabled
RXD
TXD
VDD
Disabled
Receiver
Transmitter Disabled
RXD
TXD
Disabled
Automatic Echo
Local Loopback
Remote Loopback VDD
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34.6 Universal Asynchronous Receiver Transceiver (UART) User Interface
Table 34-3. Register Mapping
Offset Register Name Access Reset
0x0000 Control Register UART_CR Write-only –
0x0004 Mode Register UART_MR Read-write 0x0
0x0008 Interrupt Enable Register UART_IER Write-only –
0x000C Interrupt Disable Register UART_IDR Write-only –
0x0010 Interrupt Mask Register UART_IMR Read-only 0x0
0x0014 Status Register UART_SR Read-only –
0x0018 Receive Holding Register UART_RHR Read-only 0x0
0x001C Transmit Holding Register UART_THR Write-only –
0x0020 Baud Rate Generator Register UART_BRGR Read-write 0x0
0x0024 - 0x003C Reserved – – –
0x004C - 0x00FC Reserved – – –
0x0100 - 0x0124 PDC Area – – –
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34.6.1 UART Control Register
Name: UART_CR
Address: 0x400E0800
Access: Write-only
• RSTRX: Reset Receiver
0 = No effect.
1 = The receiver logic is reset and disabled. If a character is being received, the reception is aborted.
• RSTTX: Reset Transmitter
0 = No effect.
1 = The transmitter logic is reset and disabled. If a character is being transmitted, the transmission is aborted.
• RXEN: Receiver Enable
0 = No effect.
1 = The receiver is enabled if RXDIS is 0.
• RXDIS: Receiver Disable
0 = No effect.
1 = The receiver is disabled. If a character is being processed and RSTRX is not set, the character is completed before the
receiver is stopped.
• TXEN: Transmitter Enable
0 = No effect.
1 = The transmitter is enabled if TXDIS is 0.
• TXDIS: Transmitter Disable
0 = No effect.
1 = The transmitter is disabled. If a character is being processed and a character has been written in the UART_THR and
RSTTX is not set, both characters are completed before the transmitter is stopped.
• RSTSTA: Reset Status Bits
0 = No effect.
1 = Resets the status bits PARE, FRAME and OVRE in the UART_SR.
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2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––––––
RSTSTA
76543210
TXDISTXEN RXDISRXEN RSTTX RSTRX ––
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34.6.2 UART Mode Register
Name: UART_MR
Address: 0x400E0804
Access: Read-write
•PAR: Parity Type
• CHMODE: Channel Mode
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––––––––
15 14 1312 11 10 9 8
CHMODE –– PAR –
76543210
––––––––
Value Name Description
0 EVEN Even parity
1ODD Odd parity
2SPACE Space: parity forced to 0
3MARK Mark: parity forced to 1
4NO No parity
Value Name Description
0 NORMAL Normal Mode
1AUTOMATIC Automatic Echo
2 LOCAL_LOOPBACK Local Loopback
3 REMOTE_LOOPBACK Remote Loopback
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34.6.3 UART Interrupt Enable Register
Name: UART_IER
Address: 0x400E0808
Access: Write-only
• RXRDY: Enable RXRDY Interrupt
• TXRDY: Enable TXRDY Interrupt
• ENDRX: Enable End of Receive Transfer Interrupt
• ENDTX: Enable End of Transmit Interrupt
• OVRE: Enable Overrun Error Interrupt
• FRAME: Enable Framing Error Interrupt
• PARE: Enable Parity Error Interrupt
• TXEMPTY: Enable TXEMPTY Interrupt
• TXBUFE: Enable Buffer Empty Interrupt
• RXBUFF: Enable Buffer Full Interrupt
0 = No effect.
1 = Enables the corresponding interrupt.
3130292827 26 25 24
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2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––
RXBUFF TXBUFE –TXEMPTY –
76543210
PARE FRAME OVRE ENDTX ENDRX –TXRDY RXRDY
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34.6.4 UART Interrupt Disable Register
Name: UART_IDR
Address: 0x400E080C
Access: Write-only
• RXRDY: Disable RXRDY Interrupt
• TXRDY: Disable TXRDY Interrupt
• ENDRX: Disable End of Receive Transfer Interrupt
• ENDTX: Disable End of Transmit Interrupt
• OVRE: Disable Overrun Error Interrupt
• FRAME: Disable Framing Error Interrupt
• PARE: Disable Parity Error Interrupt
• TXEMPTY: Disable TXEMPTY Interrupt
• TXBUFE: Disable Buffer Empty Interrupt
• RXBUFF: Disable Buffer Full Interrupt
0 = No effect.
1 = Disables the corresponding interrupt.
3130292827 26 25 24
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2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––
RXBUFF TXBUFE –TXEMPTY –
76543210
PARE FRAME OVRE ENDTX ENDRX –TXRDY RXRDY
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34.6.5 UART Interrupt Mask Register
Name: UART_IMR
Address: 0x400E0810
Access: Read-only
• RXRDY: Mask RXRDY Interrupt
• TXRDY: Disable TXRDY Interrupt
• ENDRX: Mask End of Receive Transfer Interrupt
• ENDTX: Mask End of Transmit Interrupt
• OVRE: Mask Overrun Error Interrupt
• FRAME: Mask Framing Error Interrupt
• PARE: Mask Parity Error Interrupt
• TXEMPTY: Mask TXEMPTY Interrupt
• TXBUFE: Mask TXBUFE Interrupt
• RXBUFF: Mask RXBUFF Interrupt
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
3130292827 26 25 24
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2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––
RXBUFF TXBUFE –TXEMPTY –
76543210
PARE FRAME OVRE ENDTX ENDRX –TXRDY RXRDY
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34.6.6 UART Status Register
Name: UART_SR
Address: 0x400E0814
Access: Read-only
• RXRDY: Receiver Ready
0 = No character has been received since the last read of the UART_RHR or the receiver is disabled.
1 = At least one complete character has been received, transferred to UART_RHR and not yet read.
• TXRDY: Transmitter Ready
0 = A character has been written to UART_THR and not yet transferred to the Shift Register, or the transmitter is disabled.
1 = There is no character written to UART_THR not yet transferred to the Shift Register.
• ENDRX: End of Receiver Transfer
0 = The End of Transfer signal from the receiver Peripheral Data Controller channel is inactive.
1 = The End of Transfer signal from the receiver Peripheral Data Controller channel is active.
• ENDTX: End of Transmitter Transfer
0 = The End of Transfer signal from the transmitter Peripheral Data Controller channel is inactive.
1 = The End of Transfer signal from the transmitter Peripheral Data Controller channel is active.
• OVRE: Overrun Error
0 = No overrun error has occurred since the last RSTSTA.
1 = At least one overrun error has occurred since the last RSTSTA.
•FRAME: Framing Error
0 = No framing error has occurred since the last RSTSTA.
1 = At least one framing error has occurred since the last RSTSTA.
• PARE: Parity Error
0 = No parity error has occurred since the last RSTSTA.
1 = At least one parity error has occurred since the last RSTSTA.
• TXEMPTY: Transmitter Empty
0 = There are characters in UART_THR, or characters being processed by the transmitter, or the transmitter is disabled.
1 = There are no characters in UART_THR and there are no characters being processed by the transmitter.
3130292827 26 25 24
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2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
–––
RXBUFF TXBUFE –TXEMPTY –
76543210
PARE FRAME OVRE ENDTX ENDRX –TXRDY RXRDY
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• TXBUFE: Transmission Buffer Empty
0 = The buffer empty signal from the transmitter PDC channel is inactive.
1 = The buffer empty signal from the transmitter PDC channel is active.
• RXBUFF: Receive Buffer Full
0 = The buffer full signal from the receiver PDC channel is inactive.
1 = The buffer full signal from the receiver PDC channel is active.
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34.6.7 UART Receiver Holding Register
Name: UART_RHR
Address: 0x400E0818
Access: Read-only
• RXCHR: Received Character
Last received character if RXRDY is set.
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15 14 1312 11 10 9 8
––––––––
76543210
RXCHR
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34.6.8 UART Transmit Holding Register
Name: UART_THR
Address: 0x400E081C
Access: Write-only
• TXCHR: Character to be Transmitted
Next character to be transmitted after the current character if TXRDY is not set.
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15 14 1312 11 10 9 8
––––––––
76543210
TXCHR
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34.6.9 UART Baud Rate Generator Register
Name: UART_BRGR
Address: 0x400E0820
Access: Read-write
• CD: Clock Divisor
0 = Baud Rate Clock is disabled
1 to 65,535 = MCK / (CD x 16)
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15 14 1312 11 10 9 8
CD
76543210
CD
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35. Universal Synchronous Asynchronous Receiver Transmitter (USART)
35.1 Description
The Universal Synchronous Asynchronous Receiver Transceiver (USART) provides one full duplex universal
synchronous asynchronous serial link. Data frame format is widely programmable (data length, parity, number of
stop bits) to support a maximum of standards. The receiver implements parity error, framing error and overrun
error detection. The receiver time-out enables handling variable-length frames and the transmitter timeguard
facilitates communications with slow remote devices. Multidrop communications are also supported through
address bit handling in reception and transmission.
The USART features three test modes: remote loopback, local loopback and automatic echo.
The USART supports specific operating modes providing interfaces on RS485, LIN and SPI buses, with ISO7816
T = 0 or T = 1 smart card slots and infrared transceivers. The hardware handshaking feature enables an out-of-
band flow control by automatic management of the pins RTS and CTS.
The USART supports the connection to the Peripheral DMA Controller, which enables data transfers to the
transmitter and from the receiver. The PDC provides chained buffer management without any intervention of the
processor.
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35.2 Embedded Characteristics
Programmable Baud Rate Generator
5- to 9-bit Full-duplex Synchronous or Asynchronous Serial Communications
̶1, 1.5 or 2 Stop Bits in Asynchronous Mode or 1 or 2 Stop Bits in Synchronous Mode
̶Parity Generation and Error Detection
̶Framing Error Detection, Overrun Error Detection
̶MSB- or LSB-first
̶Optional Break Generation and Detection
̶By 8 or by 16 Over-sampling Receiver Frequency
̶Optional Hardware Handshaking RTS-CTS
̶Receiver Time-out and Transmitter Timeguard
̶Optional Multidrop Mode with Address Generation and Detection
RS485 with Driver Control Signal
ISO7816, T = 0 or T = 1 Protocols for Interfacing with Smart Cards
̶NACK Handling, Error Counter with Repetition and Iteration Limit
IrDA Modulation and Demodulation
̶Communication at up to 115.2 Kbps
SPI Mode
̶Master or Slave
̶Serial Clock Programmable Phase and Polarity
̶SPI Serial Clock (SCK) Frequency up to Internal Clock Frequency MCK/6
LIN Mode (USART0 only)
̶Compliant with LIN 1.3 and LIN 2.0 specifications
̶Master or Slave
̶Processing of frames with up to 256 data bytes
̶Response Data length can be configurable or defined automatically by the Identifier
̶Self synchronization in Slave node configuration
̶Automatic processing and verification of the “Synch Break” and the “Synch Field”
̶The “Synch Break” is detected even if it is partially superimposed with a data byte
̶Automatic Identifier parity calculation/sending and verification
̶Parity sending and verification can be disabled
̶Automatic Checksum calculation/sending and verification
̶Checksum sending and verification can be disabled
̶Support both “Classic” and “Enhanced” checksum types
̶Full LIN error checking and reporting
̶Frame Slot Mode: the Master allocates slots to the scheduled frames automatically.
̶Generation of the Wakeup signal
Test Modes
̶Remote Loopback, Local Loopback, Automatic Echo
Supports Connection of Two Peripheral DMA Controller Channels (PDC)
̶Offers Buffer Transfer without Processor Intervention
$3 6
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35.3 Block Diagram
Figure 35-1. USART Block Diagram
Table 35-1. SPI Operating Mode
PIN USART SPI Slave SPI Master
RXD RXD MOSI MISO
TXD TXD MISO MOSI
RTS RTS – CS
CTS CTS CS –
(Peripheral) DMA
Controller
Channel Channel
Interrupt
Controller
Receiver
USART
Interrupt
RXD
TXD
SCK
USART PIO
Controller
CTS
RTS
Transmitter
Baud Rate
Generator
User Interface
PMC MCK
SLCK
DIV MCK/DIV
APB
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35.4 Application Block Diagram
Figure 35-2. Application Block Diagram
35.5 I/O Lines Description
Smart
Card
Slot
USART
RS485
Drivers
Differential
Bus
IrDA
Transceivers
Field Bus
Driver EMV
Driver IrDA
Driver
IrLAP
RS232
Drivers
Serial
Port
Serial
Driver
PPP
LIN
Driver
LIN
Transceiver
SPI
Driver
SPI
Bus
Table 35-2. I/O Line Description
Name Description Type Active Level
SCK Serial Clock I/O
TXD
Transmit Serial Data
or Master Out Slave In (MOSI) in SPI Master Mode
or Master In Slave Out (MISO) in SPI Slave Mode
I/O
RXD
Receive Serial Data
or Master In Slave Out (MISO) in SPI Master Mode
or Master Out Slave In (MOSI) in SPI Slave Mode
Input
CTS Clear to Send
or Slave Select (NSS) in SPI Slave Mode Input Low
RTS Request to Send
or Slave Select (NSS) in SPI Master Mode Output Low
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35.6 Product Dependencies
35.6.1 I/O Lines
The pins used for interfacing the USART may be multiplexed with the PIO lines. The programmer must first
program the PIO controller to assign the desired USART pins to their peripheral function. If I/O lines of the USART
are not used by the application, they can be used for other purposes by the PIO Controller.
To prevent the TXD line from falling when the USART is disabled, the use of an internal pull up is mandatory. If the
hardware handshaking feature is used, the internal pull up on TXD must also be enabled.
35.6.2 Power Management
The USART is not continuously clocked. The programmer must first enable the USART Clock in the Power
Management Controller (PMC) before using the USART. However, if the application does not require USART
operations, the USART clock can be stopped when not needed and be restarted later. In this case, the USART will
resume its operations where it left off.
Configuring the USART does not require the USART clock to be enabled.
Table 35-3. I/O Lines
Instance Signal I/O Line Peripheral
USART0 CTS0 PB26 A
USART0 RTS0 PB25 A
USART0 RXD0 PA10 A
USART0 SCK0 PA17 B
USART0 TXD0 PA11 A
USART1 CTS1 PA15 A
USART1 RTS1 PA14 A
USART1 RXD1 PA12 A
USART1 SCK1 PA16 A
USART1 TXD1 PA13 A
USART2 CTS2 PB23 A
USART2 RTS2 PB22 A
USART2 RXD2 PB21 A
USART2 SCK2 PB24 A
USART2 TXD2 PB20 A
USART3 CTS3 PF4 A
USART3 RTS3 PF5 A
USART3 RXD3 PD5 B
USART3 SCK3 PE16 B
USART3 TXD3 PD4 B
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35.6.3 Interrupt
The USART interrupt line is connected on one of the internal sources of the Interrupt Controller. Using the USART
interrupt requires the Interrupt Controller to be programmed first. Note that it is not recommended to use the
USART interrupt line in edge sensitive mode.
Table 35-4. Peripheral IDs
Instance ID
USART0 17
USART1 18
USART2 19
USART3 20
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35.7 Functional Description
The USART is capable of managing several types of serial synchronous or asynchronous communications.
It supports the following communication modes:
5- to 9-bit full-duplex asynchronous serial communication
̶MSB- or LSB-first
̶1, 1.5 or 2 stop bits
̶Parity even, odd, marked, space or none
̶By 8 or by 16 over-sampling receiver frequency
̶Optional hardware handshaking
̶Optional break management
̶Optional multidrop serial communication
High-speed 5- to 9-bit full-duplex synchronous serial communication
̶MSB- or LSB-first
̶1 or 2 stop bits
̶Parity even, odd, marked, space or none
̶By 8 or by 16 over-sampling frequency
̶Optional hardware handshaking
̶Optional break management
̶Optional multidrop serial communication
RS485 with driver control signal
ISO7816, T0 or T1 protocols for interfacing with smart cards
̶NACK handling, error counter with repetition and iteration limit, inverted data.
InfraRed IrDA Modulation and Demodulation
SPI Mode
̶Master or Slave
̶Serial Clock Programmable Phase and Polarity
̶SPI Serial Clock (SCK) Frequency up to Internal Clock Frequency MCK/6
LIN Mode (USART0 only)
̶Compliant with LIN 1.3 and LIN 2.0 specifications
̶Master or Slave
̶Processing of frames with up to 256 data bytes
̶Response Data length can be configurable or defined automatically by the Identifier
̶Self synchronization in Slave node configuration
̶Automatic processing and verification of the “Synch Break” and the “Synch Field”
̶The “Synch Break” is detected even if it is partially superimposed with a data byte
̶Automatic Identifier parity calculation/sending and verification
̶Parity sending and verification can be disabled
̶Automatic Checksum calculation/sending and verification
̶Checksum sending and verification can be disabled
̶Support both “Classic” and “Enhanced” checksum types
̶Full LIN error checking and reporting
̶Frame Slot Mode: the Master allocates slots to the scheduled frames automatically.
̶Generation of the Wakeup signal
Test modes
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̶Remote loopback, local loopback, automatic echo
USCLKS |:| AtmeL
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35.7.1 Baud Rate Generator
The Baud Rate Generator provides the bit period clock named the Baud Rate Clock to both the receiver and the
transmitter.
The Baud Rate Generator clock source can be selected by setting the USCLKS field in the Mode Register
(US_MR) between:
the Master Clock MCK
a division of the Master Clock, the divider being product dependent, but generally set to 8
the external clock, available on the SCK pin
The Baud Rate Generator is based upon a 16-bit divider, which is programmed with the CD field of the Baud Rate
Generator Register (US_BRGR). If CD is programmed to 0, the Baud Rate Generator does not generate any
clock. If CD is programmed to 1, the divider is bypassed and becomes inactive.
If the external SCK clock is selected, the duration of the low and high levels of the signal provided on the SCK pin
must be longer than a Master Clock (MCK) period. The frequency of the signal provided on SCK must be at least
3 times lower than MCK in USART mode, or 6 in SPI mode.
Figure 35-3. Baud Rate Generator
35.7.1.1 Baud Rate in Asynchronous Mode
If the USART is programmed to operate in asynchronous mode, the selected clock is first divided by CD, which is
field programmed in the Baud Rate Generator Register (US_BRGR). The resulting clock is provided to the receiver
as a sampling clock and then divided by 16 or 8, depending on the programming of the OVER bit in US_MR.
If OVER is set to 1, the receiver sampling is 8 times higher than the baud rate clock. If OVER is cleared, the
sampling is performed at 16 times the baud rate clock.
The following formula performs the calculation of the Baud Rate.
This gives a maximum baud rate of MCK divided by 8, assuming that MCK is the highest possible clock and that
OVER is programmed to 1.
MCK/DIV
16-bit Counter
0
Baud Rate
Clock
CD
CD
Sampling
Divider
0
1
>1
Sampling
Clock
Reserved
MCK
SCK
USCLKS
OVER
SCK
SYNC
SYNC
USCLKS = 3
1
0
2
3
0
1
0
1
FIDI
Baudrate SelectedClock
82 Over–()CD()
--------------------------------------------
=
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Baud Rate Calculation Example
Table 35-5 shows calculations of CD to obtain a baud rate at 38400 bauds for different source clock frequencies.
This table also shows the actual resulting baud rate and the error.
The baud rate is calculated with the following formula:
The baud rate error is calculated with the following formula. It is not recommended to work with an error higher
than 5%.
35.7.1.2 Fractional Baud Rate in Asynchronous Mode
The Baud Rate generator previously defined is subject to the following limitation: the output frequency changes by
only integer multiples of the reference frequency. An approach to this problem is to integrate a fractional N clock
generator that has a high resolution. The generator architecture is modified to obtain Baud Rate changes by a
fraction of the reference source clock. This fractional part is programmed with the FP field in the Baud Rate
Generator Register (US_BRGR). If FP is not 0, the fractional part is activated. The resolution is one eighth of the
Table 35-5. Baud Rate Example (OVER = 0)
Source Clock Expected Baud
Rate Calculation Result CD Actual Baud Rate Error
MHz Bit/s Bit/s
3 686 400 38 400 6.00 6 38 400.00 0.00%
4 915 200 38 400 8.00 8 38 400.00 0.00%
5 000 000 38 400 8.14 8 39 062.50 1.70%
7 372 800 38 400 12.00 12 38 400.00 0.00%
8 000 000 38 400 13.02 13 38 461.54 0.16%
12 000 000 38 400 19.53 20 37 500.00 2.40%
12 288 000 38 400 20.00 20 38 400.00 0.00%
14 318 180 38 400 23.30 23 38 908.10 1.31%
14 745 600 38 400 24.00 24 38 400.00 0.00%
18 432 000 38 400 30.00 30 38 400.00 0.00%
24 000 000 38 400 39.06 39 38 461.54 0.16%
24 576 000 38 400 40.00 40 38 400.00 0.00%
25 000 000 38 400 40.69 40 38 109.76 0.76%
32 000 000 38 400 52.08 52 38 461.54 0.16%
32 768 000 38 400 53.33 53 38 641.51 0.63%
33 000 000 38 400 53.71 54 38 194.44 0.54%
40 000 000 38 400 65.10 65 38 461.54 0.16%
50 000 000 38 400 81.38 81 38 580.25 0.47%
60 000 000 38 400 97.66 98 38 265.31 0.35%
70 000 000 38 400 113.93 114 38 377.19 0.06%
BaudRate MCK CD 16×⁄=
Error 1ExpectedBaudRate
ActualBaudRate
---------------------------------------------------


–=
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clock divider. This feature is only available when using USART normal mode. The fractional Baud Rate is
calculated using the following formula:
The modified architecture is presented below:
Figure 35-4. Fractional Baud Rate Generator
35.7.1.3 Baud Rate in Synchronous Mode or SPI Mode
If the USART is programmed to operate in synchronous mode, the selected clock is simply divided by the field CD
in US_BRGR.
In synchronous mode, if the external clock is selected (USCLKS = 3), the clock is provided directly by the signal on
the USART SCK pin. No division is active. The value written in US_BRGR has no effect. The external clock
frequency must be at least 3 times lower than the system clock. In synchronous mode master (USCLKS = 0 or 1,
CLK0 set to 1), the receive part limits the SCK maximum frequency to MCK/3 in USART mode, or MCK/6 in SPI
mode.
When either the external clock SCK or the internal clock divided (MCK/DIV) is selected, the value programmed in
CD must be even if the user has to ensure a 50:50 mark/space ratio on the SCK pin. If the internal clock MCK is
selected, the Baud Rate Generator ensures a 50:50 duty cycle on the SCK pin, even if the value programmed in
CD is odd.
Baudrate SelectedClock
82 Over–()CD FP
8
-------
+




----------------------------------------------------------------
=
MCK/DIV
16-bit Counter
0
Baud Rate
Clock
CD
CD
Sampling
Divider
0
1
>1
Sampling
Clock
Reserved
MCK
SCK
USCLKS
OVER
SCK
SYNC
SYNC
USCLKS = 3
1
0
2
3
0
1
0
1
FIDI
glitch-free
logic
Modulus
Control
FP
FP
BaudRate SelectedClock
CD
--------------------------------------
=
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35.7.1.4 Baud Rate in ISO 7816 Mode
The ISO7816 specification defines the bit rate with the following formula:
where:
B is the bit rate
Di is the bit-rate adjustment factor
Fi is the clock frequency division factor
f is the ISO7816 clock frequency (Hz)
Di is a binary value encoded on a 4-bit field, named DI, as represented in Table 35-6.
Fi is a binary value encoded on a 4-bit field, named FI, as represented in Table 35-7.
Table 35-8 shows the resulting Fi/Di Ratio, which is the ratio between the ISO7816 clock and the baud rate clock.
If the USART is configured in ISO7816 Mode, the clock selected by the USCLKS field in the Mode Register
(US_MR) is first divided by the value programmed in the field CD in the Baud Rate Generator Register
(US_BRGR). The resulting clock can be provided to the SCK pin to feed the smart card clock inputs. This means
that the CLKO bit can be set in US_MR.
This clock is then divided by the value programmed in the FI_DI_RATIO field in the FI_DI_Ratio register
(US_FIDI). This is performed by the Sampling Divider, which performs a division by up to 2047 in ISO7816 Mode.
The non-integer values of the Fi/Di Ratio are not supported and the user must program the FI_DI_RATIO field to a
value as close as possible to the expected value.
The FI_DI_RATIO field resets to the value 0x174 (372 in decimal) and is the most common divider between the
ISO7816 clock and the bit rate (Fi = 372, Di = 1).
Figure 35-5 shows the relation between the Elementary Time Unit, corresponding to a bit time, and the ISO 7816
clock.
BDi
Fi
------f×=
Table 35-6. Binary and Decimal Values for Di
DI field 0001 0010 0011 0100 0101 0110 1000 1001
Di (decimal) 1 2 4 8 16 32 12 20
Table 35-7. Binary and Decimal Values for Fi
FI field 0000 0001 0010 0011 0100 0101 0110 1001 1010 1011 1100 1101
Fi (decimal) 372 372 558 744 1116 1488 1860 512 768 1024 1536 2048
Table 35-8. Possible Values for the Fi/Di Ratio
Fi/Di 372 558 774 1116 1488 1806 512 768 1024 1536 2048
1 372 558 744 1116 1488 1860 512 768 1024 1536 2048
2 186 279 372 558 744 930 256 384 512 768 1024
4 93 139.5 186 279 372 465 128 192 256 384 512
8 46.5 69.75 93 139.5 186 232.5 64 96 128 192 256
16 23.25 34.87 46.5 69.75 93 116.2 32 48 64 96 128
32 11.62 17.43 23.25 34.87 46.5 58.13 16 24 32 48 64
12 31 46.5 62 93 124 155 42.66 64 85.33 128 170.6
20 18.6 27.9 37.2 55.8 74.4 93 25.6 38.4 51.2 76.8 102.4
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Figure 35-5. Elementary Time Unit (ETU)
35.7.2 Receiver and Transmitter Control
After reset, the receiver is disabled. The user must enable the receiver by setting the RXEN bit in the Control
Register (US_CR). However, the receiver registers can be programmed before the receiver clock is enabled.
After reset, the transmitter is disabled. The user must enable it by setting the TXEN bit in the Control Register
(US_CR). However, the transmitter registers can be programmed before being enabled.
The Receiver and the Transmitter can be enabled together or independently.
At any time, the software can perform a reset on the receiver or the transmitter of the USART by setting the
corresponding bit, RSTRX and RSTTX respectively, in the Control Register (US_CR). The software resets clear
the status flag and reset internal state machines but the user interface configuration registers hold the value
configured prior to software reset. Regardless of what the receiver or the transmitter is performing, the
communication is immediately stopped.
The user can also independently disable the receiver or the transmitter by setting RXDIS and TXDIS respectively
in US_CR. If the receiver is disabled during a character reception, the USART waits until the end of reception of
the current character, then the reception is stopped. If the transmitter is disabled while it is operating, the USART
waits the end of transmission of both the current character and character being stored in the Transmit Holding
Register (US_THR). If a timeguard is programmed, it is handled normally.
35.7.3 Synchronous and Asynchronous Modes
35.7.3.1 Transmitter Operations
The transmitter performs the same in both synchronous and asynchronous operating modes (SYNC = 0 or SYNC
= 1). One start bit, up to 9 data bits, one optional parity bit and up to two stop bits are successively shifted out on
the TXD pin at each falling edge of the programmed serial clock.
The number of data bits is selected by the CHRL field and the MODE 9 bit in the Mode Register (US_MR). Nine
bits are selected by setting the MODE 9 bit regardless of the CHRL field. The parity bit is set according to the PAR
field in US_MR. The even, odd, space, marked or none parity bit can be configured. The MSBF field in US_MR
configures which data bit is sent first. If written to 1, the most significant bit is sent first. If written to 0, the less
significant bit is sent first. The number of stop bits is selected by the NBSTOP field in US_MR. The 1.5 stop bit is
supported in asynchronous mode only.
1 ETU
ISO7816 Clock
on SCK
ISO7816 I/O Line
on TXD
FI_DI_RATIO
ISO7816 Clock Cycles
_|||||||||||||||||||||| T T _|_I—\_I— _| I— AtmeL
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Figure 35-6. Character Transmit
The characters are sent by writing in the Transmit Holding Register (US_THR). The transmitter reports two status
bits in the Channel Status Register (US_CSR): TXRDY (Transmitter Ready), which indicates that US_THR is
empty and TXEMPTY, which indicates that all the characters written in US_THR have been processed. When the
current character processing is completed, the last character written in US_THR is transferred into the Shift
Register of the transmitter and US_THR becomes empty, thus TXRDY rises.
Both TXRDY and TXEMPTY bits are low when the transmitter is disabled. Writing a character in US_THR while
TXRDY is low has no effect and the written character is lost.
Figure 35-7. Transmitter Status
35.7.3.2 Manchester Encoder
When the Manchester encoder is in use, characters transmitted through the USART are encoded based on
biphase Manchester II format. To enable this mode, set the MAN field in the US_MR register to 1. Depending on
polarity configuration, a logic level (zero or one), is transmitted as a coded signal one-to-zero or zero-to-one. Thus,
a transition always occurs at the midpoint of each bit time. It consumes more bandwidth than the original NRZ
signal (2x) but the receiver has more error control since the expected input must show a change at the center of a
bit cell. An example of Manchester encoded sequence is: the byte 0xB1 or 10110001 encodes to 10 01 10 10 01
01 01 10, assuming the default polarity of the encoder. Figure 35-8 illustrates this coding scheme.
Figure 35-8. NRZ to Manchester Encoding
D0 D1 D2 D3D4 D5 D6 D7
TXD
Start
Bit Parity
Bit Stop
Bit
Example: 8-bit, Parity Enabled One Stop
Baud Rate
Clock
D0 D1 D2 D3D4 D5 D6 D7
TXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
Start
Bit
Write
US_THR
D0 D1 D2 D3D4 D5 D6 D7 Parity
Bit Stop
Bit
TXRDY
TXEMPTY
NRZ
encoded
data
Manchester
encoded
data
10110001
Txd
M I I I I I I I I :::::: M I I I I I I I I I II: I“ u |_| |_| i w i |_|_LIDE«EAIII AtmeL
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The Manchester encoded character can also be encapsulated by adding both a configurable preamble and a start
frame delimiter pattern. Depending on the configuration, the preamble is a training sequence, composed of a pre-
defined pattern with a programmable length from 1 to 15 bit times. If the preamble length is set to 0, the preamble
waveform is not generated prior to any character. The preamble pattern is chosen among the following sequences:
ALL_ONE, ALL_ZERO, ONE_ZERO or ZERO_ONE, writing the field TX_PP in the US_MAN register, the field
TX_PL is used to configure the preamble length. Figure 35-9 illustrates and defines the valid patterns. To improve
flexibility, the encoding scheme can be configured using the TX_MPOL field in the US_MAN register. If the
TX_MPOL field is set to zero (default), a logic zero is encoded with a zero-to-one transition and a logic one is
encoded with a one-to-zero transition. If the TX_MPOL field is set to one, a logic one is encoded with a one-to-zero
transition and a logic zero is encoded with a zero-to-one transition.
Figure 35-9. Preamble Patterns, Default Polarity Assumed
A start frame delimiter is to be configured using the ONEBIT field in the US_MR register. It consists of a user-
defined pattern that indicates the beginning of a valid data. Figure 35-10 illustrates these patterns. If the start
frame delimiter, also known as start bit, is one bit, (ONEBIT to 1), a logic zero is Manchester encoded and
indicates that a new character is being sent serially on the line. If the start frame delimiter is a synchronization
pattern also referred to as sync (ONEBIT to 0), a sequence of 3 bit times is sent serially on the line to indicate the
start of a new character. The sync waveform is in itself an invalid Manchester waveform as the transition occurs at
the middle of the second bit time. Two distinct sync patterns are used: the command sync and the data sync. The
command sync has a logic one level for one and a half bit times, then a transition to logic zero for the second one
and a half bit times. If the MODSYNC field in the US_MR register is set to 1, the next character is a command. If it
is set to 0, the next character is a data. When direct memory access is used, the MODSYNC field can be
immediately updated with a modified character located in memory. To enable this mode, VAR_SYNC field in
US_MR register must be set to 1. In this case, the MODSYNC field in US_MR is bypassed and the sync
configuration is held in the TXSYNH in the US_THR register. The USART character format is modified and
includes sync information.
Manchester
encoded
dataTxd SFD DATA
8 bit width "ALL_ONE" Preamble
Manchester
encoded
dataTxd SFD DATA
8 bit width "ALL_ZERO" Preamble
Manchester
encoded
dataTxd SFD DATA
8 bit width "ZERO_ONE" Preamble
Manchester
encoded
dataTxd SFD DATA
8 bit width "ONE_ZERO" Preamble
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Figure 35-10. Start Frame Delimiter
Drift Compensation
Drift compensation is available only in 16X oversampling mode. An hardware recovery system allows a larger
clock drift. To enable the hardware system, the bit in the USART_MAN register must be set. If the RXD edge is
one 16X clock cycle from the expected edge, this is considered as normal jitter and no corrective actions is taken.
If the RXD event is between 4 and 2 clock cycles before the expected edge, then the current period is shortened
by one clock cycle. If the RXD event is between 2 and 3 clock cycles after the expected edge, then the current
period is lengthened by one clock cycle. These intervals are considered to be drift and so corrective actions are
automatically taken.
Figure 35-11. Bit Resynchronization
Manchester
encoded
dataTxd
SFD
DATA
One bit start frame delimiter
Preamble Length
is set to 0
Manchester
encoded
dataTxd
SFD
DATA
Command Sync
start frame delimiter
Manchester
encoded
dataTxd
SFD
DATA
Data Sync
start frame delimiter
RXD
Oversampling
16x Clock
Sampling
point
Expected edge
Tolerance
Synchro.
Jump
Sync
Jump
Synchro.
Error
Synchro.
Error
1—I—\—I_ W ‘H I'l— HHHHIIIIIIIIIIIIIIIT ‘fl—fl— TTTIHTTHTT B FWWMWTU—UTLTU—LF _l | AtmeL
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35.7.3.3 Asynchronous Receiver
If the USART is programmed in asynchronous operating mode (SYNC = 0), the receiver oversamples the RXD
input line. The oversampling is either 16 or 8 times the Baud Rate clock, depending on the OVER bit in the Mode
Register (US_MR).
The receiver samples the RXD line. If the line is sampled during one half of a bit time to 0, a start bit is detected
and data, parity and stop bits are successively sampled on the bit rate clock.
If the oversampling is 16, (OVER to 0), a start is detected at the eighth sample to 0. Then, data bits, parity bit and
stop bit are sampled on each 16 sampling clock cycle. If the oversampling is 8 (OVER to 1), a start bit is detected
at the fourth sample to 0. Then, data bits, parity bit and stop bit are sampled on each 8 sampling clock cycle.
The number of data bits, first bit sent and parity mode are selected by the same fields and bits as the transmitter,
i.e. respectively CHRL, MODE9, MSBF and PAR. For the synchronization mechanism only, the number of stop
bits has no effect on the receiver as it considers only one stop bit, regardless of the field NBSTOP, so that
resynchronization between the receiver and the transmitter can occur. Moreover, as soon as the stop bit is
sampled, the receiver starts looking for a new start bit so that resynchronization can also be accomplished when
the transmitter is operating with one stop bit.
Figure 35-12 and Figure 35-13 illustrate start detection and character reception when USART operates in
asynchronous mode.
Figure 35-12. Asynchronous Start Detection
Figure 35-13. Asynchronous Character Reception
Sampling
Clock (x16)
RXD
Start
Detection
Sampling
Baud Rate
Clock
RXD
Start
Rejection
Sampling
12345678
123456701234
123456789 1011121314 15 16 D0
Sampling
D0 D1 D2 D3D4 D5 D6 D7
RXD
Parity
Bit Stop
Bit
Example: 8-bit, Parity Enabled
Baud Rate
Clock
Start
Detection 16
samples16
samples16
samples16
samples16
samples16
samples16
samples16
samples16
samples16
samples
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35.7.3.4 Manchester Decoder
When the MAN field in US_MR register is set to 1, the Manchester decoder is enabled. The decoder performs both
preamble and start frame delimiter detection. One input line is dedicated to Manchester encoded input data.
An optional preamble sequence can be defined, its length is user-defined and totally independent of the emitter
side. Use RX_PL in US_MAN register to configure the length of the preamble sequence. If the length is set to 0, no
preamble is detected and the function is disabled. In addition, the polarity of the input stream is programmable with
RX_MPOL field in US_MAN register. Depending on the desired application the preamble pattern matching is to be
defined via the RX_PP field in US_MAN. See Figure 35-9 for available preamble patterns.
Unlike preamble, the start frame delimiter is shared between Manchester Encoder and Decoder. So, if ONEBIT
field is set to 1, only a zero encoded Manchester can be detected as a valid start frame delimiter. If ONEBIT is set
to 0, only a sync pattern is detected as a valid start frame delimiter. Decoder operates by detecting transition on
incoming stream. If RXD is sampled during one quarter of a bit time to zero, a start bit is detected. See Figure 35-
14. The sample pulse rejection mechanism applies.
Figure 35-14. Asynchronous Start Bit Detection
The receiver is activated and starts Preamble and Frame Delimiter detection, sampling the data at one quarter and
then three quarters. If a valid preamble pattern or start frame delimiter is detected, the receiver continues decoding
with the same synchronization. If the stream does not match a valid pattern or a valid start frame delimiter, the
receiver re-synchronizes on the next valid edge.The minimum time threshold to estimate the bit value is three
quarters of a bit time.
If a valid preamble (if used) followed with a valid start frame delimiter is detected, the incoming stream is decoded
into NRZ data and passed to USART for processing. Figure 35-15 illustrates Manchester pattern mismatch. When
incoming data stream is passed to the USART, the receiver is also able to detect Manchester code violation. A
code violation is a lack of transition in the middle of a bit cell. In this case, MANE flag in US_CSR register is raised.
It is cleared by writing the Control Register (US_CR) with the RSTSTA bit to 1. See Figure 35-16 for an example of
Manchester error detection during data phase.
Figure 35-15. Preamble Pattern Mismatch
Manchester
encoded
dataTxd
1234
Sampling
Clock
(16 x)
Start
Detection
Manchester
encoded
dataTxd SFD DATA
Preamble Length is set to 8
Preamble Mismatch
invalid pattern
Preamble Mismatch
Manchester coding error
eeeeee Lé fi—Q 7 h AtmeL
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Figure 35-16. Manchester Error Flag
When the start frame delimiter is a sync pattern (ONEBIT field to 0), both command and data delimiter are
supported. If a valid sync is detected, the received character is written as RXCHR field in the US_RHR register and
the RXSYNH is updated. RXCHR is set to 1 when the received character is a command, and it is set to 0 if the
received character is a data. This mechanism alleviates and simplifies the direct memory access as the character
contains its own sync field in the same register.
As the decoder is setup to be used in unipolar mode, the first bit of the frame has to be a zero-to-one transition.
35.7.3.5 Radio Interface: Manchester Encoded USART Application
This section describes low data rate RF transmission systems and their integration with a Manchester encoded
USART. These systems are based on transmitter and receiver ICs that support ASK and FSK modulation
schemes.
The goal is to perform full duplex radio transmission of characters using two different frequency carriers. See the
configuration in Figure 35-17.
Figure 35-17. Manchester Encoded Characters RF Transmission
Manchester
encoded
data Txd
SFD
Preamble Length
is set to 4
Elementary character bit time
Manchester
Coding Error
detected
sampling points
Preamble subpacket
and Start Frame Delimiter
were successfully
decoded
Entering USART character area
LNA
VCO
RF filter
Demod
control bi-dir
line
PA
RF filter
Mod
VCO
control
Manchester
decoder
Manchester
encoder
USART
Receiver
USART
Emitter
ASK/FSK
Upstream Receiver
ASK/FSK
downstream transmitter
Upstream
Emitter
Downstream
Receiver
Serial
Configuration
Interface
Fup frequency Carrier
Fdown frequency Carrier
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The USART module is configured as a Manchester encoder/decoder. Looking at the downstream communication
channel, Manchester encoded characters are serially sent to the RF emitter. This may also include a user defined
preamble and a start frame delimiter. Mostly, preamble is used in the RF receiver to distinguish between a valid
data from a transmitter and signals due to noise. The Manchester stream is then modulated. See Figure 35-18 for
an example of ASK modulation scheme. When a logic one is sent to the ASK modulator, the power amplifier,
referred to as PA, is enabled and transmits an RF signal at downstream frequency. When a logic zero is
transmitted, the RF signal is turned off. If the FSK modulator is activated, two different frequencies are used to
transmit data. When a logic 1 is sent, the modulator outputs an RF signal at frequency F0 and switches to F1 if the
data sent is a 0. See Figure 35-19.
From the receiver side, another carrier frequency is used. The RF receiver performs a bit check operation
examining demodulated data stream. If a valid pattern is detected, the receiver switches to receiving mode. The
demodulated stream is sent to the Manchester decoder. Because of bit checking inside RF IC, the data transferred
to the microcontroller is reduced by a user-defined number of bits. The Manchester preamble length is to be
defined in accordance with the RF IC configuration.
Figure 35-18. ASK Modulator Output
Figure 35-19. FSK Modulator Output
35.7.3.6 Synchronous Receiver
In synchronous mode (SYNC = 1), the receiver samples the RXD signal on each rising edge of the Baud Rate
Clock. If a low level is detected, it is considered as a start. All data bits, the parity bit and the stop bits are sampled
and the receiver waits for the next start bit. Synchronous mode operations provide a high speed transfer capability.
Configuration fields and bits are the same as in asynchronous mode.
Figure 35-20 illustrates a character reception in synchronous mode.
Manchester
encoded
data
default polarity
unipolar output
Txd
ASK Modulator
Output
Uptstream Frequency F0
NRZ stream
10 0 1
Manchester
encoded
data
default polarity
unipolar output
Txd
FSK Modulator
Output
Uptstream Frequencies
[F0, F0+offset]
NRZ stream
10 0 1
WWW _|||||||||||||||||||||| AtmeL
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Figure 35-20. Synchronous Mode Character Reception
35.7.3.7 Receiver Operations
When a character reception is completed, it is transferred to the Receive Holding Register (US_RHR) and the
RXRDY bit in the Status Register (US_CSR) rises. If a character is completed while the RXRDY is set, the OVRE
(Overrun Error) bit is set. The last character is transferred into US_RHR and overwrites the previous one. The
OVRE bit is cleared by writing the Control Register (US_CR) with the RSTSTA (Reset Status) bit to 1.
Figure 35-21. Receiver Status
35.7.3.8 Parity
The USART supports five parity modes selected by programming the PAR field in the Mode Register (US_MR).
The PAR field also enables the Multidrop mode, see “Multidrop Mode” on page 790. Even and odd parity bit
generation and error detection are supported.
If even parity is selected, the parity generator of the transmitter drives the parity bit to 0 if a number of 1s in the
character data bit is even, and to 1 if the number of 1s is odd. Accordingly, the receiver parity checker counts the
number of received 1s and reports a parity error if the sampled parity bit does not correspond. If odd parity is
selected, the parity generator of the transmitter drives the parity bit to 1 if a number of 1s in the character data bit
is even, and to 0 if the number of 1s is odd. Accordingly, the receiver parity checker counts the number of received
1s and reports a parity error if the sampled parity bit does not correspond. If the mark parity is used, the parity
generator of the transmitter drives the parity bit to 1 for all characters. The receiver parity checker reports an error
if the parity bit is sampled to 0. If the space parity is used, the parity generator of the transmitter drives the parity bit
to 0 for all characters. The receiver parity checker reports an error if the parity bit is sampled to 1. If parity is
disabled, the transmitter does not generate any parity bit and the receiver does not report any parity error.
D0 D1 D2 D3D4 D5 D6 D7
RXD
Start
Sampling
Parity Bit
Stop Bit
Example: 8-bit, Parity Enabled 1 Stop
Baud Rate
Clock
D0 D1 D2 D3D4 D5 D6 D7
RXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
Write
US_CR
RXRDY
OVRE
D0 D1 D2 D3D4 D5 D6 D7
Start
Bit Parity
Bit Stop
Bit
RSTSTA = 1
Read
US_RHR
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Table 35-9 shows an example of the parity bit for the character 0x41 (character ASCII “A”) depending on the
configuration of the USART. Because there are two bits to 1, 1 bit is added when a parity is odd, or 0 is added
when a parity is even.
When the receiver detects a parity error, it sets the PARE (Parity Error) bit in the Channel Status Register
(US_CSR). The PARE bit can be cleared by writing the Control Register (US_CR) with the RSTSTA bit to 1. Figure
35-22 illustrates the parity bit status setting and clearing.
Figure 35-22. Parity Error
35.7.3.9 Multidrop Mode
If the PAR field in the Mode Register (US_MR) is programmed to the value 0x6 or 0x07, the USART runs in
Multidrop Mode. This mode differentiates the data characters and the address characters. Data is transmitted with
the parity bit to 0 and addresses are transmitted with the parity bit to 1.
If the USART is configured in multidrop mode, the receiver sets the PARE parity error bit when the parity bit is high
and the transmitter is able to send a character with the parity bit high when the Control Register is written with the
SENDA bit to 1.
To handle parity error, the PARE bit is cleared when the Control Register is written with the bit RSTSTA to 1.
The transmitter sends an address byte (parity bit set) when SENDA is written to US_CR. In this case, the next byte
written to US_THR is transmitted as an address. Any character written in US_THR without having written the
command SENDA is transmitted normally with the parity to 0.
35.7.3.10 Transmitter Timeguard
The timeguard feature enables the USART interface with slow remote devices.
The timeguard function enables the transmitter to insert an idle state on the TXD line between two characters. This
idle state actually acts as a long stop bit.
Table 35-9. Parity Bit Examples
Character Hexa Binary Parity Bit Parity Mode
A 0x41 0100 0001 1 Odd
A 0x41 0100 0001 0 Even
A 0x41 0100 0001 1 Mark
A 0x41 0100 0001 0 Space
A 0x41 0100 0001 None None
D0 D1 D2 D3D4 D5 D6 D7
RXD
Start
Bit Bad
Parity
Bit
Stop
Bit
Baud Rate
Clock
Write
US_CR
PARE
RXRDY
RSTSTA = 1
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The duration of the idle state is programmed in the TG field of the Transmitter Timeguard Register (US_TTGR).
When this field is programmed to zero no timeguard is generated. Otherwise, the transmitter holds a high level on
TXD after each transmitted byte during the number of bit periods programmed in TG in addition to the number of
stop bits.
As illustrated in Figure 35-23, the behavior of TXRDY and TXEMPTY status bits is modified by the programming of
a timeguard. TXRDY rises only when the start bit of the next character is sent, and thus remains to 0 during the
timeguard transmission if a character has been written in US_THR. TXEMPTY remains low until the timeguard
transmission is completed as the timeguard is part of the current character being transmitted.
Figure 35-23. Timeguard Operations
Table 35-10 indicates the maximum length of a timeguard period that the transmitter can handle in relation to the
function of the Baud Rate.
D0 D1 D2 D3D4 D5 D6 D7
TXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
Start
Bit
TG = 4
Write
US_THR
D0 D1 D2 D3D4 D5 D6 D7 Parity
Bit Stop
Bit
TXRDY
TXEMPTY
TG = 4
Table 35-10. Maximum Timeguard Length Depending on Baud Rate
Baud Rate Bit time Timeguard
Bit/sec µs ms
1 200 833 212.50
9 600 104 26.56
14400 69.4 17.71
19200 52.1 13.28
28800 34.7 8.85
33400 29.9 7.63
56000 17.9 4.55
57600 17.4 4.43
115200 8.7 2.21
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35.7.3.11 Receiver Time-out
The Receiver Time-out provides support in handling variable-length frames. This feature detects an idle condition
on the RXD line. When a time-out is detected, the bit TIMEOUT in the Channel Status Register (US_CSR) rises
and can generate an interrupt, thus indicating to the driver an end of frame.
The time-out delay period (during which the receiver waits for a new character) is programmed in the TO field of
the Receiver Time-out Register (US_RTOR). If the TO field is programmed to 0, the Receiver Time-out is disabled
and no time-out is detected. The TIMEOUT bit in US_CSR remains to 0. Otherwise, the receiver loads a 16-bit
counter with the value programmed in TO. This counter is decremented at each bit period and reloaded each time
a new character is received. If the counter reaches 0, the TIMEOUT bit in the Status Register rises. Then, the user
can either:
Stop the counter clock until a new character is received. This is performed by writing the Control Register
(US_CR) with the STTTO (Start Time-out) bit to 1. In this case, the idle state on RXD before a new character
is received will not provide a time-out. This prevents having to handle an interrupt before a character is
received and allows waiting for the next idle state on RXD after a frame is received.
Obtain an interrupt while no character is received. This is performed by writing US_CR with the RETTO
(Reload and Start Time-out) bit to 1. If RETTO is performed, the counter starts counting down immediately
from the value TO. This enables generation of a periodic interrupt so that a user time-out can be handled, for
example when no key is pressed on a keyboard.
If STTTO is performed, the counter clock is stopped until a first character is received. The idle state on RXD before
the start of the frame does not provide a time-out. This prevents having to obtain a periodic interrupt and enables a
wait of the end of frame when the idle state on RXD is detected.
If RETTO is performed, the counter starts counting down immediately from the value TO. This enables generation
of a periodic interrupt so that a user time-out can be handled, for example when no key is pressed on a keyboard.
Figure 35-24 shows the block diagram of the Receiver Time-out feature.
Figure 35-24. Receiver Time-out Block Diagram
Table 35-11 gives the maximum time-out period for some standard baud rates.
Table 35-11. Maximum Time-out Period
Baud Rate Bit Time Time-out
bit/sec µs ms
600 1 667 109 225
1 200 833 54 613
2 400 417 27 306
4 800 208 13 653
9 600 104 6 827
16-bit Time-out
Counter
0
TO
TIMEOUT
Baud Rate
Clock
=
Character
Received
RETTO
Load
Clock
16-bit
Value
STTTO
DQ
1
Clear
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35.7.3.12 Framing Error
The receiver is capable of detecting framing errors. A framing error happens when the stop bit of a received
character is detected at level 0. This can occur if the receiver and the transmitter are fully desynchronized.
A framing error is reported on the FRAME bit of the Channel Status Register (US_CSR). The FRAME bit is
asserted in the middle of the stop bit as soon as the framing error is detected. It is cleared by writing the Control
Register (US_CR) with the RSTSTA bit to 1.
Figure 35-25. Framing Error Status
35.7.3.13 Transmit Break
The user can request the transmitter to generate a break condition on the TXD line. A break condition drives the
TXD line low during at least one complete character. It appears the same as a 0x00 character sent with the parity
and the stop bits to 0. However, the transmitter holds the TXD line at least during one character until the user
requests the break condition to be removed.
A break is transmitted by writing the Control Register (US_CR) with the STTBRK bit to 1. This can be performed at
any time, either while the transmitter is empty (no character in either the Shift Register or in US_THR) or when a
character is being transmitted. If a break is requested while a character is being shifted out, the character is first
completed before the TXD line is held low.
Once STTBRK command is requested further STTBRK commands are ignored until the end of the break is
completed.
The break condition is removed by writing US_CR with the STPBRK bit to 1. If the STPBRK is requested before
the end of the minimum break duration (one character, including start, data, parity and stop bits), the transmitter
ensures that the break condition completes.
14400 69 4 551
19200 52 3 413
28800 35 2 276
33400 30 1 962
56000 18 1 170
57600 17 1 138
200000 5 328
Table 35-11. Maximum Time-out Period (Continued)
Baud Rate Bit Time Time-out
D0 D1 D2 D3D4 D5 D6 D7
RXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
Write
US_CR
FRAME
RXRDY
RSTSTA = 1
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The transmitter considers the break as though it is a character, i.e. the STTBRK and STPBRK commands are
taken into account only if the TXRDY bit in US_CSR is to 1 and the start of the break condition clears the TXRDY
and TXEMPTY bits as if a character is processed.
Writing US_CR with both STTBRK and STPBRK bits to 1 can lead to an unpredictable result. All STPBRK
commands requested without a previous STTBRK command are ignored. A byte written into the Transmit Holding
Register while a break is pending, but not started, is ignored.
After the break condition, the transmitter returns the TXD line to 1 for a minimum of 12 bit times. Thus, the
transmitter ensures that the remote receiver detects correctly the end of break and the start of the next character.
If the timeguard is programmed with a value higher than 12, the TXD line is held high for the timeguard period.
After holding the TXD line for this period, the transmitter resumes normal operations.
Figure 35-26 illustrates the effect of both the Start Break (STTBRK) and Stop Break (STPBRK) commands on the
TXD line.
Figure 35-26. Break Transmission
35.7.3.14 Receive Break
The receiver detects a break condition when all data, parity and stop bits are low. This corresponds to detecting a
framing error with data to 0x00, but FRAME remains low.
When the low stop bit is detected, the receiver asserts the RXBRK bit in US_CSR. This bit may be cleared by
writing the Control Register (US_CR) with the bit RSTSTA to 1.
An end of receive break is detected by a high level for at least 2/16 of a bit period in asynchronous operating mode
or one sample at high level in synchronous operating mode. The end of break detection also asserts the RXBRK
bit.
35.7.3.15 Hardware Handshaking
The USART features a hardware handshaking out-of-band flow control. The RTS and CTS pins are used to
connect with the remote device, as shown in Figure 35-27.
D0 D1 D2 D3D4 D5 D6 D7
TXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
Write
US_CR
TXRDY
TXEMPTY
STPBRK = 1
STTBRK = 1
Break Transmission End of Break
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Figure 35-27. Connection with a Remote Device for Hardware Handshaking
Setting the USART to operate with hardware handshaking is performed by writing the USART_MODE field in the
Mode Register (US_MR) to the value 0x2.
The USART behavior when hardware handshaking is enabled is the same as the behavior in standard
synchronous or asynchronous mode, except that the receiver drives the RTS pin as described below and the level
on the CTS pin modifies the behavior of the transmitter as described below. Using this mode requires using the
PDC channel for reception. The transmitter can handle hardware handshaking in any case.
Figure 35-28 shows how the receiver operates if hardware handshaking is enabled. The RTS pin is driven high if
the receiver is disabled and if the status RXBUFF (Receive Buffer Full) coming from the PDC channel is high.
Normally, the remote device does not start transmitting while its CTS pin (driven by RTS) is high. As soon as the
Receiver is enabled, the RTS falls, indicating to the remote device that it can start transmitting. Defining a new
buffer to the PDC clears the status bit RXBUFF and, as a result, asserts the pin RTS low.
Figure 35-28. Receiver Behavior when Operating with Hardware Handshaking
Figure 35-29 shows how the transmitter operates if hardware handshaking is enabled. The CTS pin disables the
transmitter. If a character is being processing, the transmitter is disabled only after the completion of the current
character and transmission of the next character happens as soon as the pin CTS falls.
Figure 35-29. Transmitter Behavior when Operating with Hardware Handshaking
35.7.4 ISO7816 Mode
The USART features an ISO7816-compatible operating mode. This mode permits interfacing with smart cards and
Security Access Modules (SAM) communicating through an ISO7816 link. Both T = 0 and T = 1 protocols defined
by the ISO7816 specification are supported.
Setting the USART in ISO7816 mode is performed by writing the USART_MODE field in the Mode Register
(US_MR) to the value 0x4 for protocol T = 0 and to the value 0x5 for protocol T = 1.
USART
TXD
CTS
Remote
Device
RXD
TXDRXD
RTS
RTS
CTS
RTS
RXBUFF
Write
US_CR
RXEN = 1
RXD
RXDIS = 1
CTS
TXD
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35.7.4.1 ISO7816 Mode Overview
The ISO7816 is a half duplex communication on only one bidirectional line. The baud rate is determined by a
division of the clock provided to the remote device (see “Baud Rate Generator” on page 777).
The USART connects to a smart card as shown in Figure 35-30. The TXD line becomes bidirectional and the Baud
Rate Generator feeds the ISO7816 clock on the SCK pin. As the TXD pin becomes bidirectional, its output remains
driven by the output of the transmitter but only when the transmitter is active while its input is directed to the input
of the receiver. The USART is considered as the master of the communication as it generates the clock.
Figure 35-30. Connection of a Smart Card to the USART
When operating in ISO7816, either in T = 0 or T = 1 modes, the character format is fixed. The configuration is 8
data bits, even parity and 1 or 2 stop bits, regardless of the values programmed in the CHRL, MODE9, PAR and
CHMODE fields. MSBF can be used to transmit LSB or MSB first. Parity Bit (PAR) can be used to transmit in
normal or inverse mode. Refer to “USART Mode Register” on page 827 and “PAR: Parity Type” on page 828.
The USART cannot operate concurrently in both receiver and transmitter modes as the communication is
unidirectional at a time. It has to be configured according to the required mode by enabling or disabling either the
receiver or the transmitter as desired. Enabling both the receiver and the transmitter at the same time in ISO7816
mode may lead to unpredictable results.
The ISO7816 specification defines an inverse transmission format. Data bits of the character must be transmitted
on the I/O line at their negative value. The USART does not support this format and the user has to perform an
exclusive OR on the data before writing it in the Transmit Holding Register (US_THR) or after reading it in the
Receive Holding Register (US_RHR).
35.7.4.2 Protocol T = 0
In T = 0 protocol, a character is made up of one start bit, eight data bits, one parity bit and one guard time, which
lasts two bit times. The transmitter shifts out the bits and does not drive the I/O line during the guard time.
If no parity error is detected, the I/O line remains to 1 during the guard time and the transmitter can continue with
the transmission of the next character, as shown in Figure 35-31.
If a parity error is detected by the receiver, it drives the I/O line to 0 during the guard time, as shown in Figure 35-
32. This error bit is also named NACK, for Non Acknowledge. In this case, the character lasts 1 bit time more, as
the guard time length is the same and is added to the error bit time which lasts 1 bit time.
When the USART is the receiver and it detects an error, it does not load the erroneous character in the Receive
Holding Register (US_RHR). It appropriately sets the PARE bit in the Status Register (US_SR) so that the
software can handle the error.
Smart
Card
SCK CLK
TXD I/O
USART
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Figure 35-31. T = 0 Protocol without Parity Error
Figure 35-32. T = 0 Protocol with Parity Error
Receive Error Counter
The USART receiver also records the total number of errors. This can be read in the Number of Error (US_NER)
register. The NB_ERRORS field can record up to 255 errors. Reading US_NER automatically clears the
NB_ERRORS field.
Receive NACK Inhibit
The USART can also be configured to inhibit an error. This can be achieved by setting the INACK bit in the Mode
Register (US_MR). If INACK is to 1, no error signal is driven on the I/O line even if a parity bit is detected.
Moreover, if INACK is set, the erroneous received character is stored in the Receive Holding Register, as if no
error occurred and the RXRDY bit does rise.
Transmit Character Repetition
When the USART is transmitting a character and gets a NACK, it can automatically repeat the character before
moving on to the next one. Repetition is enabled by writing the MAX_ITERATION field in the Mode Register
(US_MR) at a value higher than 0. Each character can be transmitted up to eight times; the first transmission plus
seven repetitions.
If MAX_ITERATION does not equal zero, the USART repeats the character as many times as the value loaded in
MAX_ITERATION.
When the USART repetition number reaches MAX_ITERATION, the ITERATION bit is set in the Channel Status
Register (US_CSR). If the repetition of the character is acknowledged by the receiver, the repetitions are stopped
and the iteration counter is cleared.
The ITERATION bit in US_CSR can be cleared by writing the Control Register with the RSIT bit to 1.
Disable Successive Receive NACK
The receiver can limit the number of successive NACKs sent back to the remote transmitter. This is programmed
by setting the bit DSNACK in the Mode Register (US_MR). The maximum number of NACK transmitted is
programmed in the MAX_ITERATION field. As soon as MAX_ITERATION is reached, the character is considered
as correct, an acknowledge is sent on the line and the ITERATION bit in the Channel Status Register is set.
35.7.4.3 Protocol T = 1
When operating in ISO7816 protocol T = 1, the transmission is similar to an asynchronous format with only one
stop bit. The parity is generated when transmitting and checked when receiving. Parity error detection sets the
PARE bit in the Channel Status Register (US_CSR).
D0 D1 D2 D3D4 D5 D6 D7
RXD
Parity
Bit
Baud Rate
Clock
Start
Bit Guard
Time 1 Next
Start
Bit
Guard
Time 2
D0 D1 D2 D3D4 D5 D6 D7
I/O
Parity
Bit
Baud Rate
Clock
Start
Bit Guard
Time 1 Start
Bit
Guard
Time 2 D0 D1
Error
Repetition
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35.7.5 IrDA Mode
The USART features an IrDA mode supplying half-duplex point-to-point wireless communication. It embeds the
modulator and demodulator which allows a glueless connection to the infrared transceivers, as shown in Figure
35-33. The modulator and demodulator are compliant with the IrDA specification version 1.1 and support data
transfer speeds ranging from 2.4 Kb/s to 115.2 Kb/s.
The USART IrDA mode is enabled by setting the USART_MODE field in the Mode Register (US_MR) to the value
0x8. The IrDA Filter Register (US_IF) allows configuring the demodulator filter. The USART transmitter and
receiver operate in a normal asynchronous mode and all parameters are accessible. Note that the modulator and
the demodulator are activated.
Figure 35-33. Connection to IrDA Transceivers
The receiver and the transmitter must be enabled or disabled according to the direction of the transmission to be
managed.
To receive IrDA signals, the following needs to be done:
Disable TX and Enable RX
Configure the TXD pin as PIO and set it as an output to 0 (to avoid LED emission). Disable the internal pull-
up (better for power consumption).
Receive data
35.7.5.1 IrDA Modulation
For baud rates up to and including 115.2 Kbits/sec, the RZI modulation scheme is used. “0” is represented by a
light pulse of 3/16th of a bit time. Some examples of signal pulse duration are shown in Table 35-12.
Figure 35-34 shows an example of character transmission.
IrDA
Transceivers
RXD RX
TXD
TX
USART
Demodulator
Modulator
Receiver
Transmitter
Table 35-12. IrDA Pulse Duration
Baud Rate Pulse Duration (3/16)
2.4 Kb/s 78.13 µs
9.6 Kb/s 19.53 µs
19.2 Kb/s 9.77 µs
38.4 Kb/s 4.88 µs
57.6 Kb/s 3.26 µs
115.2 Kb/s 1.63 µs
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Figure 35-34. IrDA Modulation
35.7.5.2 IrDA Baud Rate
Table 35-13 gives some examples of CD values, baud rate error and pulse duration. Note that the requirement on
the maximum acceptable error of ±1.87% must be met.
Bit Period Bit Period
3
16
Start
Bit Data BitsStop
Bit
00
000
111 1
1
Transmitter
Output
TXD
Table 35-13. IrDA Baud Rate Error
Peripheral Clock Baud Rate CD Baud Rate Error Pulse Time
3 686 400 115 200 2 0.00% 1.63
20 000 000 115 200 11 1.38% 1.63
32 768 000 115 200 18 1.25% 1.63
40 000 000 115 200 22 1.38% 1.63
3 686 400 57 600 4 0.00% 3.26
20 000 000 57 600 22 1.38% 3.26
32 768 000 57 600 36 1.25% 3.26
40 000 000 57 600 43 0.93% 3.26
3 686 400 38 400 6 0.00% 4.88
20 000 000 38 400 33 1.38% 4.88
32 768 000 38 400 53 0.63% 4.88
40 000 000 38 400 65 0.16% 4.88
3 686 400 19 200 12 0.00% 9.77
20 000 000 19 200 65 0.16% 9.77
32 768 000 19 200 107 0.31% 9.77
40 000 000 19 200 130 0.16% 9.77
3 686 400 9 600 24 0.00% 19.53
20 000 000 9 600 130 0.16% 19.53
32 768 000 9 600 213 0.16% 19.53
40 000 000 9 600 260 0.16% 19.53
3 686 400 2 400 96 0.00% 78.13
20 000 000 2 400 521 0.03% 78.13
32 768 000 2 400 853 0.04% 78.13
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35.7.5.3 IrDA Demodulator
The demodulator is based on the IrDA Receive filter comprised of an 8-bit down counter which is loaded with the
value programmed in US_IF. When a falling edge is detected on the RXD pin, the Filter Counter starts counting
down at the Master Clock (MCK) speed. If a rising edge is detected on the RXD pin, the counter stops and is
reloaded with US_IF. If no rising edge is detected when the counter reaches 0, the input of the receiver is driven
low during one bit time.
Figure 35-35 illustrates the operations of the IrDA demodulator.
Figure 35-35. IrDA Demodulator Operations
As the IrDA mode uses the same logic as the ISO7816, note that the FI_DI_RATIO field in US_FIDI must be set to
a value higher than 0 in order to assure IrDA communications operate correctly.
MCK
RXD
Receiver
Input
Pulse
Rejected
65432 6 1
65432 0
Pulse
Accepted
Counter
Value
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35.7.6 RS485 Mode
The USART features the RS485 mode to enable line driver control. While operating in RS485 mode, the USART
behaves as though in asynchronous or synchronous mode and configuration of all the parameters is possible. The
difference is that the RTS pin is driven high when the transmitter is operating. The behavior of the RTS pin is
controlled by the TXEMPTY bit. A typical connection of the USART to a RS485 bus is shown in Figure 35-36.
Figure 35-36. Typical Connection to a RS485 Bus
The USART is set in RS485 mode by programming the USART_MODE field in the Mode Register (US_MR) to the
value 0x1.
The RTS pin is at a level inverse to the TXEMPTY bit. Significantly, the RTS pin remains high when a timeguard is
programmed so that the line can remain driven after the last character completion. Figure 35-37 gives an example
of the RTS waveform during a character transmission when the timeguard is enabled.
Figure 35-37. Example of RTS Drive with Timeguard
USART
RTS
TXD
RXD
Differential
Bus
D0 D1 D2 D3D4 D5 D6 D7
TXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
TG = 4
Write
US_THR
TXRDY
TXEMPTY
RTS
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35.7.7 SPI Mode
The Serial Peripheral Interface (SPI) Mode is a synchronous serial data link that provides communication with
external devices in Master or Slave Mode. It also enables communication between processors if an external
processor is connected to the system.
The Serial Peripheral Interface is essentially a shift register that serially transmits data bits to other SPIs. During a
data transfer, one SPI system acts as the “master” which controls the data flow, while the other devices act as
“slaves'' which have data shifted into and out by the master. Different CPUs can take turns being masters and one
master may simultaneously shift data into multiple slaves. (Multiple Master Protocol is the opposite of Single
Master Protocol, where one CPU is always the master while all of the others are always slaves.) However, only
one slave may drive its output to write data back to the master at any given time.
A slave device is selected when its NSS signal is asserted by the master. The USART in SPI Master mode can
address only one SPI Slave because it can generate only one NSS signal.
The SPI system consists of two data lines and two control lines:
Master Out Slave In (MOSI): This data line supplies the output data from the master shifted into the input of
the slave.
Master In Slave Out (MISO): This data line supplies the output data from a slave to the input of the master.
Serial Clock (SCK): This control line is driven by the master and regulates the flow of the data bits. The
master may transmit data at a variety of baud rates. The SCK line cycles once for each bit that is
transmitted.
Slave Select (NSS): This control line allows the master to select or deselect the slave.
35.7.7.1 Modes of Operation
The USART can operate in SPI Master Mode or in SPI Slave Mode.
Operation in SPI Master Mode is programmed by writing to 0xE the USART_MODE field in the Mode Register. In
this case the SPI lines must be connected as described below:
the MOSI line is driven by the output pin TXD
the MISO line drives the input pin RXD
the SCK line is driven by the output pin SCK
the NSS line is driven by the output pin RTS
Operation in SPI Slave Mode is programmed by writing to 0xF the USART_MODE field in the Mode Register. In
this case the SPI lines must be connected as described below:
the MOSI line drives the input pin RXD
the MISO line is driven by the output pin TXD
the SCK line drives the input pin SCK
the NSS line drives the input pin CTS
In order to avoid unpredicted behavior, any change of the SPI Mode must be followed by a software reset of the
transmitter and of the receiver (except the initial configuration after a hardware reset). (See Section 35.7.8.3).
35.7.7.2 Baud Rate
In SPI Mode, the baudrate generator operates in the same way as in USART synchronous mode: See “Baud Rate
in Synchronous Mode or SPI Mode” on page 779. However, there are some restrictions:
In SPI Master Mode:
the external clock SCK must not be selected (USCLKS ≠ 0x3), and the bit CLKO must be set to “1” in the
Mode Register (US_MR), in order to generate correctly the serial clock on the SCK pin.
to obtain correct behavior of the receiver and the transmitter, the value programmed in CD must be superior
or equal to 6.
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if the internal clock divided (MCK/DIV) is selected, the value programmed in CD must be even to ensure a
50:50 mark/space ratio on the SCK pin, this value can be odd if the internal clock is selected (MCK).
In SPI Slave Mode:
the external clock (SCK) selection is forced regardless of the value of the USCLKS field in the Mode
Register (US_MR). Likewise, the value written in US_BRGR has no effect, because the clock is provided
directly by the signal on the USART SCK pin.
to obtain correct behavior of the receiver and the transmitter, the external clock (SCK) frequency must be at
least 6 times lower than the system clock.
35.7.7.3 Data Transfer
Up to 9 data bits are successively shifted out on the TXD pin at each rising or falling edge (depending of CPOL and
CPHA) of the programmed serial clock. There is no Start bit, no Parity bit and no Stop bit.
The number of data bits is selected by the CHRL field and the MODE 9 bit in the Mode Register (US_MR). The 9
bits are selected by setting the MODE 9 bit regardless of the CHRL field. The MSB data bit is always sent first in
SPI Mode (Master or Slave).
Four combinations of polarity and phase are available for data transfers. The clock polarity is programmed with the
CPOL bit in the Mode Register. The clock phase is programmed with the CPHA bit. These two parameters
determine the edges of the clock signal upon which data is driven and sampled. Each of the two parameters has
two possible states, resulting in four possible combinations that are incompatible with one another. Thus, a
master/slave pair must use the same parameter pair values to communicate. If multiple slaves are used and fixed
in different configurations, the master must reconfigure itself each time it needs to communicate with a different
slave.
Table 35-14. SPI Bus Protocol Mode
SPI Bus Protocol Mode CPOL CPHA
001
100
211
310
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Figure 35-38. SPI Transfer Format (CPHA=1, 8 bits per transfer)
Figure 35-39. SPI Transfer Format (CPHA=0, 8 bits per transfer)
6
SCK
(CPOL = 0)
SCK
(CPOL = 1)
MOSI
SPI Master ->TXD
SPI Slave -> RXD
NSS
SPI Master -> RTS
SPI Slave -> CTS
SCK cycle (for reference)
MSB
MSB
LSB
LSB
6
6
5
5
4
4
3
3
2
2
1
1
12345 786
MISO
SPI Master ->RXD
SPI Slave -> TXD
SCK
(CPOL = 0)
SCK
(CPOL = 1)
12345 7
MOSI
SPI Master -> TXD
SPI Slave -> RXD
MISO
SPI Master -> RXD
SPI Slave -> TXD
NSS
SPI Master -> RTS
SPI Slave -> CTS
SCK cycle (for reference) 8
MSB
MSB
LSB
LSB
6
6
5
5
4
4
3
3
1
1
2
2
6
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35.7.7.4 Receiver and Transmitter Control
See “Receiver and Transmitter Control” on page 781.
35.7.7.5 Character Transmission
The characters are sent by writing in the Transmit Holding Register (US_THR). An additional condition for
transmitting a character can be added when the USART is configured in SPI master mode. In the USART_MR
register, the value configured on INACK field can prevent any character transmission (even if US_THR has been
written) while the receiver side is not ready (character not read). When INACK equals 0, the character is
transmitted whatever the receiver status. If INACK is set to 1, the transmitter waits for the receiver holding register
to be read before transmitting the character (RXRDY flag cleared), thus preventing any overflow (character loss)
on the receiver side.
The transmitter reports two status bits in the Channel Status Register (US_CSR): TXRDY (Transmitter Ready),
which indicates that US_THR is empty and TXEMPTY, which indicates that all the characters written in US_THR
have been processed. When the current character processing is completed, the last character written in US_THR
is transferred into the Shift Register of the transmitter and US_THR becomes empty, thus TXRDY rises.
Both TXRDY and TXEMPTY bits are low when the transmitter is disabled. Writing a character in US_THR while
TXRDY is low has no effect and the written character is lost.
If the USART is in SPI Slave Mode and if a character must be sent while the Transmit Holding Register (US_THR)
is empty, the UNRE (Underrun Error) bit is set. The TXD transmission line stays at high level during all this time.
The UNRE bit is cleared by writing the Control Register (US_CR) with the RSTSTA (Reset Status) bit to 1.
In SPI Master Mode, the slave select line (NSS) is asserted at low level 1 Tbit (Time bit) before the transmission of
the MSB bit and released at high level 1 Tbit after the transmission of the LSB bit. So, the slave select line (NSS)
is always released between each character transmission and a minimum delay of 3 Tbits always inserted.
However, in order to address slave devices supporting the CSAAT mode (Chip Select Active After Transfer), the
slave select line (NSS) can be forced at low level by writing the Control Register (US_CR) with the RTSEN bit to 1.
The slave select line (NSS) can be released at high level only by writing the Control Register (US_CR) with the
RTSDIS bit to 1 (for example, when all data have been transferred to the slave device).
In SPI Slave Mode, the transmitter does not require a falling edge of the slave select line (NSS) to initiate a
character transmission but only a low level. However, this low level must be present on the slave select line (NSS)
at least 1 Tbit before the first serial clock cycle corresponding to the MSB bit.
35.7.7.6 Character Reception
When a character reception is completed, it is transferred to the Receive Holding Register (US_RHR) and the
RXRDY bit in the Status Register (US_CSR) rises. If a character is completed while RXRDY is set, the OVRE
(Overrun Error) bit is set. The last character is transferred into US_RHR and overwrites the previous one. The
OVRE bit is cleared by writing the Control Register (US_CR) with the RSTSTA (Reset Status) bit to 1.
To ensure correct behavior of the receiver in SPI Slave Mode, the master device sending the frame must ensure a
minimum delay of 1 Tbit between each character transmission. The receiver does not require a falling edge of the
slave select line (NSS) to initiate a character reception but only a low level. However, this low level must be
present on the slave select line (NSS) at least 1 Tbit before the first serial clock cycle corresponding to the MSB
bit.
35.7.7.7 Receiver Timeout
Because the receiver baudrate clock is active only during data transfers in SPI Mode, a receiver timeout is
impossible in this mode, whatever the Time-out value is (field TO) in the Time-out Register (US_RTOR).
35.7.8 LIN Mode
The LIN Mode provides Master node and Slave node connectivity on a LIN bus.
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The LIN (Local Interconnect Network) is a serial communication protocol which efficiently supports the control of
mechatronic nodes in distributed automotive applications.
The main properties of the LIN bus are:
Single Master/Multiple Slaves concept
Low cost silicon implementation based on common UART/SCI interface hardware, an equivalent in software,
or as a pure state machine.
Self synchronization without quartz or ceramic resonator in the slave nodes
Deterministic signal transmission
Low cost single-wire implementation
Speed up to 20 kbit/s
LIN provides cost efficient bus communication where the bandwidth and versatility of CAN are not required.
The LIN Mode enables processing LIN frames with a minimum of action from the microprocessor.
35.7.8.1 Modes of Operation
The USART can act either as a LIN Master node or as a LIN Slave node.
The node configuration is chosen by setting the USART_MODE field in the USART Mode register (US_MR):
LIN Master Node (USART_MODE=0xA)
LIN Slave Node (USART_MODE=0xB)
In order to avoid unpredicted behavior, any change of the LIN node configuration must be followed by a software
reset of the transmitter and of the receiver (except the initial node configuration after a hardware reset). (See
Section 35.7.8.3)
35.7.8.2 Baud Rate Configuration
See “Baud Rate in Asynchronous Mode” on page 777.
The baud rate is configured in the Baud Rate Generator register (US_BRGR).
35.7.8.3 Receiver and Transmitter Control
See “Receiver and Transmitter Control” on page 781.
35.7.8.4 Character Transmission
See “Transmitter Operations” on page 781.
35.7.8.5 Character Reception
See “Receiver Operations” on page 789.
35.7.8.6 Header Transmission (Master Node Configuration)
All the LIN Frames start with a header which is sent by the master node and consists of a Synch Break Field,
Synch Field and Identifier Field.
So in Master node configuration, the frame handling starts with the sending of the header.
The header is transmitted as soon as the identifier is written in the LIN Identifier register (US_LINIR). At this
moment the flag TXRDY falls.
The Break Field, the Synch Field and the Identifier Field are sent automatically one after the other.
The Break Field consists of 13 dominant bits and 1 recessive bit, the Synch Field is the character 0x55 and the
Identifier corresponds to the character written in the LIN Identifier Register (US_LINIR). The Identifier parity bits
can be automatically computed and sent (see Section 35.7.8.9).
The flag TXRDY rises when the identifier character is transferred into the Shift Register of the transmitter.
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As soon as the Synch Break Field is transmitted, the flag LINBK in the Channel Status register (US_CSR) is set to
1. Likewise, as soon as the Identifier Field is sent, the flag LINID in the Channel Status register (US_CSR) is set to
1. These flags are reset by writing the bit RSTSTA to 1 in the Control register (US_CR).
Figure 35-40. Header Transmission
TXD
Baud Rate
Clock
Start
Bit
Write
US_LINIR
10101010
TXRDY
Stop
Bit Start
Bit ID0 ID1 ID2 ID3ID4 ID5 ID6 ID7Break Field
13 dominant bits (at 0)
Stop
Bit
Break
Delimiter
1 recessive bit
(at 1)
Synch Byte = 0x55
US_LINIR ID
LINID
in US_CSR
LINBK
in US_CSR
Write RSTSTA=1
in US_CR
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35.7.8.7 Header Reception (Slave Node Configuration)
All the LIN Frames start with a header which is sent by the master node and consists of a Synch Break Field,
Synch Field and Identifier Field.
In Slave node configuration, the frame handling starts with the reception of the header.
The USART uses a break detection threshold of 11 nominal bit times at the actual baud rate. At any time, if 11
consecutive recessive bits are detected on the bus, the USART detects a Break Field. As long as a Break Field
has not been detected, the USART stays idle and the received data are not taken in account.
When a Break Field has been detected, the flag LINBK in the Channel Status register (US_CSR) is set to 1 and
the USART expects the Synch Field character to be 0x55. This field is used to update the actual baud rate in order
to stay synchronized (see Section 35.7.8.8). If the received Synch character is not 0x55, an Inconsistent Synch
Field error is generated (see Section 35.7.8.14).
After receiving the Synch Field, the USART expects to receive the Identifier Field.
When the Identifier Field has been received, the flag LINID in the Channel Status register (US_CSR) is set to 1. At
this moment the field IDCHR in the LIN Identifier register (US_LINIR) is updated with the received character. The
Identifier parity bits can be automatically computed and checked (see Section 35.7.8.9).
The flags LINID and LINBK are reset by writing the bit RSTSTA to 1 in the Control register (US_CR).
Figure 35-41. Header Reception
RXD
Baud Rate
Clock
te RSTSTA=1
in US_CR
LINID
US_LINIR
LINBK
Start
Bit 10101010
Stop
Bit Start
Bit ID0 ID1 ID2 ID3ID4 ID5 ID6 ID7Break Field
13 dominant bits (at 0)
Stop
Bit
Break
Delimiter
1 recessive bit
(at 1)
Synch Byte = 0x55
JLILlL|L|L|LILILILILILILILILIL||_|L|L|L||_|L|L||_||_|L||_||_||_|L||_||_||_|L||_||_|L|| / |/////////////// | AtmeL
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35.7.8.8 Slave Node Synchronization
The synchronization is done only in Slave node configuration. The procedure is based on time measurement
between falling edges of the Synch Field. The falling edges are available in distances of 2, 4, 6 and 8 bit times.
Figure 35-42. Synch Field
The time measurement is made by a 19-bit counter clocked by the sampling clock (see Section 35.7.1).
When the start bit of the Synch Field is detected, the counter is reset. Then during the next 8 Tbits of the Synch
Field, the counter is incremented. At the end of these 8 Tbits, the counter is stopped. At this moment, the 16 most
significant bits of the counter (value divided by 8) give the new clock divider (LINCD) and the 3 least significant bits
of this value (the remainder) give the new fractional part (LINFP).
When the Synch Field has been received, the clock divider (CD) and the fractional part (FP) are updated in the
Baud Rate Generator register (US_BRGR).
If it appears that the sampled Synch character is not equal to 0x55, then the error flag LINISFE in the Channel
Status register (US_CSR) is set to 1. It is reset by writing bit RSTSTA to 1 in the Control register (US_CR).
Figure 35-43. Slave Node Synchronization
The accuracy of the synchronization depends on several parameters:
The nominal clock frequency (FNom) (the theoretical slave node clock frequency)
The Baud Rate
The oversampling (Over=0 => 16X or Over=0 => 8X)
Start
bit Stop
bit
Synch Field
8 Tbit
2 Tbit 2 Tbit 2 Tbit 2 Tbit
RXD
Clock
LINIDRX
Synchro Counter 000_0011_0001_0110_1101
US_BRGR
Clcok Divider (CD)
US_BRGR
Fractional Part (FP)
Initial CD
Initial FP
Reset
US_LINBRR
Clcok Divider (CD) 0000_0110_0010_1101
US_LINBRR
Fractional Part (FP) 101
Initial CD
Initial FP
Start
Bit 10101010
Stop
Bit Start
Bit ID0 ID1 ID2 ID3ID4 ID5 ID6 ID7Break Field
13 dominant bits (at 0)
Stop
Bit
Break
Delimiter
1 recessive bit
(at 1)
Synch Byte = 0x55
V\ R m l\ v: I\ [0.5 x 8 x 2 , Over + 1] x Baudme (I) AtmeL
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The following formula is used to compute the deviation of the slave bit rate relative to the master bit rate after
synchronization (FSLAVE is the real slave node clock frequency).
FTOL_UNSYNCH is the deviation of the real slave node clock from the nominal clock frequency. The LIN Standard
imposes that it must not exceed ±15%. The LIN Standard imposes also that for communication between two
nodes, their bit rate must not differ by more than ±2%. This means that the Baudrate_deviation must not exceed
±1%.
It follows from that, a minimum value for the nominal clock frequency:
Examples:
Baudrate = 20 kbit/s, Over=0 (Oversampling 16X) => FNom(min) = 2.64 MHz
Baudrate = 20 kbit/s, Over=1 (Oversampling 8X) => FNom(min) = 1.47 MHz
Baudrate = 1 kbit/s, Over=0 (Oversampling 16X) => FNom(min) = 132 kHz
Baudrate = 1 kbit/s, Over=1 (Oversampling 8X) => FNom(min) = 74 kHz
35.7.8.9 Identifier Parity
A protected identifier consists of two sub-fields; the identifier and the identifier parity. Bits 0 to 5 are assigned to the
identifier and bits 6 and 7 are assigned to the parity.
The USART interface can generate/check these parity bits, but this feature can also be disabled. The user can
choose between two modes by the PARDIS bit of the LIN Mode register (US_LINMR):
PARDIS = 0:
During header transmission, the parity bits are computed and sent with the 6 least significant bits of the IDCHR
field of the LIN Identifier register (US_LINIR). The bits 6 and 7 of this register are discarded.
During header reception, the parity bits of the identifier are checked. If the parity bits are wrong, an Identifier Parity
error occurs (see Section 35.7.3.8). Only the 6 least significant bits of the IDCHR field are updated with the
received Identifier. The bits 6 and 7 are stuck to 0.
PARDIS = 1:
During header transmission, all the bits of the IDCHR field of the LIN Identifier register (US_LINIR) are sent on the
bus.
During header reception, all the bits of the IDCHR field are updated with the received Identifier.
Baudrate_deviation 100 α[ 82Over–()β+]Baudrate×××
8F
SLAVE
×
----------------------------------------------------------------------------------------
×


%=
Baudrate_deviation 100 α[ 82Over–()β+]Baudrate×××
8FTOL_UNSYNCH
100
--------------------------------------


xFNom
×
----------------------------------------------------------------------------------------
×





%=
0.5–α+0.5 -1 β+1<<≤≤
FNOM min() 100 0.5 8 2 Over–()×× 1+[]Baudrate×
815–
100
---------1+


×1%×
-------------------------------------------------------------------------------------------
×





Hz=
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35.7.8.10 Node Action
In function of the identifier, the node is concerned, or not, by the LIN response. Consequently, after sending or
receiving the identifier, the USART must be configured. There are three possible configurations:
PUBLISH: the node sends the response.
SUBSCRIBE: the node receives the response.
IGNORE: the node is not concerned by the response, it does not send and does not receive the response.
This configuration is made by the field, Node Action (NACT), in the US_LINMR register (see Section 35.8.16).
Example: a LIN cluster that contains a Master and two Slaves:
Data transfer from the Master to the Slave 1 and to the Slave 2:
NACT(Master)=PUBLISH
NACT(Slave1)=SUBSCRIBE
NACT(Slave2)=SUBSCRIBE
Data transfer from the Master to the Slave 1 only:
NACT(Master)=PUBLISH
NACT(Slave1)=SUBSCRIBE
NACT(Slave2)=IGNORE
Data transfer from the Slave 1 to the Master:
NACT(Master)=SUBSCRIBE
NACT(Slave1)=PUBLISH
NACT(Slave2)=IGNORE
Data transfer from the Slave1 to the Slave2:
NACT(Master)=IGNORE
NACT(Slave1)=PUBLISH
NACT(Slave2)=SUBSCRIBE
Data transfer from the Slave2 to the Master and to the Slave1:
NACT(Master)=SUBSCRIBE
NACT(Slave1)=SUBSCRIBE
NACT(Slave2)=PUBLISH
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35.7.8.11 Response Data Length
The LIN response data length is the number of data fields (bytes) of the response excluding the checksum.
The response data length can either be configured by the user or be defined automatically by bits 4 and 5 of the
Identifier (compatibility to LIN Specification 1.1). The user can choose between these two modes by the DLM bit of
the LIN Mode register (US_LINMR):
DLM = 0: the response data length is configured by the user via the DLC field of the LIN Mode register
(US_LINMR). The response data length is equal to (DLC + 1) bytes. DLC can be programmed from 0 to 255,
so the response can contain from 1 data byte up to 256 data bytes.
DLM = 1: the response data length is defined by the Identifier (IDCHR in US_LINIR) according to the table
below. The DLC field of the LIN Mode register (US_LINMR) is discarded. The response can contain 2 or 4 or
8 data bytes.
Figure 35-44. Response Data Length
35.7.8.12 Checksum
The last field of a frame is the checksum. The checksum contains the inverted 8- bit sum with carry, over all data
bytes or all data bytes and the protected identifier. Checksum calculation over the data bytes only is called classic
checksum and it is used for communication with LIN 1.3 slaves. Checksum calculation over the data bytes and the
protected identifier byte is called enhanced checksum and it is used for communication with LIN 2.0 slaves.
The USART can be configured to:
Send/Check an Enhanced checksum automatically (CHKDIS = 0 & CHKTYP = 0)
Send/Check a Classic checksum automatically (CHKDIS = 0 & CHKTYP = 1)
Not send/check a checksum (CHKDIS = 1)
This configuration is made by the Checksum Type (CHKTYP) and Checksum Disable (CHKDIS) fields of the LIN
Mode register (US_LINMR).
If the checksum feature is disabled, the user can send it manually all the same, by considering the checksum as a
normal data byte and by adding 1 to the response data length (see Section 35.7.8.11).
Table 35-15. Response Data Length if DLM = 1
IDCHR[5] IDCHR[4] Response Data Length [bytes]
00 2
01 2
10 4
11 8
User configuration: 1 - 256 data fields (DLC+1)
Identifier configuration: 2/4/8 data fields
Sync
BreakSync
Field Identifier
Field Checksum
Field
Data
Field Data
Field Data
Field Data
Field
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35.7.8.13 Frame Slot Mode
This mode is useful only for Master nodes. It respects the following rule: each frame slot shall be longer than or
equal to TFrame_Maximum.
If the Frame Slot Mode is enabled (FSDIS = 0) and a frame transfer has been completed, the TXRDY flag is set
again only after TFrame_Maximum delay, from the start of frame. So the Master node cannot send a new header
if the frame slot duration of the previous frame is inferior to TFrame_Maximum.
If the Frame Slot Mode is disabled (FSDIS = 1) and a frame transfer has been completed, the TXRDY flag is set
again immediately.
The TFrame_Maximum is calculated as below:
If the Checksum is sent (CHKDIS = 0):
THeader_Nominal = 34 x Tbit
TResponse_Nominal = 10 x (NData + 1) x Tbit
TFrame_Maximum = 1.4 x (THeader_Nominal + TResponse_Nominal + 1)(Note:)
TFrame_Maximum = 1.4 x (34 + 10 x (DLC + 1 + 1) + 1) x Tbit
TFrame_Maximum = (77 + 14 x DLC) x Tbit
If the Checksum is not sent (CHKDIS = 1):
THeader_Nominal = 34 x Tbit
TResponse_Nominal = 10 x NData x Tbit
TFrame_Maximum = 1.4 x (THeader_Nominal + TResponse_Nominal + 1(Note:))
TFrame_Maximum = 1.4 x (34 + 10 x (DLC + 1) + 1) x Tbit
TFrame_Maximum = (63 + 14 x DLC) x Tbit
Note: The term “+1” leads to an integer result for TFrame_Max (LIN Specification 1.3)
Figure 35-45. Frame Slot Mode
35.7.8.14 LIN Errors
Bit Error
This error is generated in Master of Slave node configuration, when the USART is transmitting and if the
transmitted value on the Tx line is different from the value sampled on the Rx line. If a bit error is detected, the
transmission is aborted at the next byte border.
This error is reported by flag LINBE in the Channel Status Register (US_CSR).
BreakSynch Protected
Identifier Data N Checksum
Header
Inter-
frame
space
Response
space
Frame
Frame slot = TFrame_Maximum
Response
TXRDY
Write
US_THR
Write
US_LINID
Data 1Data 2Data 3
Data3
Data N-1
Data N
Frame Slot Mode
Disabled Frame Slot Mode
Enabled
LINTC
Data 1
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Inconsistent Synch Field Error
This error is generated in Slave node configuration, if the Synch Field character received is other than 0x55.
This error is reported by flag LINISFE in the Channel Status Register (US_CSR).
Identifier Parity Error
This error is generated in Slave node configuration, if the parity of the identifier is wrong. This error can be
generated only if the parity feature is enabled (PARDIS = 0).
This error is reported by flag LINIPE in the Channel Status Register (US_CSR).
Checksum Error
This error is generated in Master of Slave node configuration, if the received checksum is wrong. This flag can be
set to “1” only if the checksum feature is enabled (CHKDIS = 0).
This error is reported by flag LINCE in the Channel Status Register (US_CSR).
Slave Not Responding Error
This error is generated in Master of Slave node configuration, when the USART expects a response from another
node (NACT = SUBSCRIBE) but no valid message appears on the bus within the time given by the maximum
length of the message frame, TFrame_Maximum (see Section 35.7.8.13). This error is disabled if the USART does
not expect any message (NACT = PUBLISH or NACT = IGNORE).
This error is reported by flag LINSNRE in the Channel Status Register (US_CSR).
35.7.8.15 LIN Frame Handling
Master Node Configuration
Write TXEN and RXEN in US_CR to enable both the transmitter and the receiver.
Write USART_MODE in US_MR to select the LIN mode and the Master Node configuration.
Write CD and FP in US_BRGR to configure the baud rate.
Write NACT, PARDIS, CHKDIS, CHKTYPE, DLCM, FSDIS and DLC in US_LINMR to configure the frame
transfer.
Check that TXRDY in US_CSR is set to “1”
Write IDCHR in US_LINIR to send the header
What comes next depends on the NACT configuration:
Case 1: NACT = PUBLISH, the USART sends the response
̶Wait until TXRDY in US_CSR rises
̶Write TCHR in US_THR to send a byte
̶If all the data have not been written, redo the two previous steps
̶Wait until LINTC in US_CSR rises
̶Check the LIN errors
Case 2: NACT = SUBSCRIBE, the USART receives the response
̶Wait until RXRDY in US_CSR rises
̶Read RCHR in US_RHR
̶If all the data have not been read, redo the two previous steps
̶Wait until LINTC in US_CSR rises
̶Check the LIN errors
Case 3: NACT = IGNORE, the USART is not concerned by the response
̶Wait until LINTC in US_CSR rises
̶Check the LIN errors
LL 'V T I [—22:31 T _| H H |'L____ H T _____ T T T _____ T L ..... '— \ L‘ TT AtmeL
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Figure 35-46. Master Node Configuration, NACT = PUBLISH
Figure 35-47. Master Node Configuration, NACT=SUBSCRIBE
Frame
BreakSynch Protected
Identifier Data 1 Data N Checksum
TXRDY
Write
US_THR
Write
US_LINIR
Data 1Data 2Data 3
Data N-1
Data N
RXRDY
Header
Inter-
frame
space
Response
space
Frame slot = TFrame_Maximum
Response
Data3
LINTC
FSDIS=1 FSDIS=0
BreakSynch Protected
Identifier Data 1 Data N Checksum
TXRDY
Read
US_RHR
Write
US_LINIR
Data 1
Data N-1
Data N-1
RXRDY
Data NData N-2
Header
Inter-
frame
space
Response
space
Frame
Frame slot = TFrame_Maximum
Response
Data3
LINTC
FSDIS=0FSDIS=1
‘I 1—!— T _____ _____ IMPORTANT AtmeL
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Figure 35-48. Master Node Configuration, NACT=IGNORE
Slave Node Configuration
Write TXEN and RXEN in US_CR to enable both the transmitter and the receiver.
Write USART_MODE in US_MR to select the LIN mode and the Slave Node configuration.
Write CD and FP in US_BRGR to configure the baud rate.
Wait until LINID in US_CSR rises
Check LINISFE and LINPE errors
Read IDCHR in US_RHR
Write NACT, PARDIS, CHKDIS, CHKTYPE, DLCM and DLC in US_LINMR to configure the frame transfer.
IMPORTANT: if the NACT configuration for this frame is PUBLISH, the US_LINMR register, must be write with
NACT = PUBLISH even if this field is already correctly configured, in order to set the TXREADY flag and the
corresponding write transfer request.
What comes next depends on the NACT configuration:
Case 1: NACT = PUBLISH, the LIN controller sends the response
̶Wait until TXRDY in US_CSR rises
̶Write TCHR in US_THR to send a byte
̶If all the data have not been written, redo the two previous steps
̶Wait until LINTC in US_CSR rises
̶Check the LIN errors
Case 2: NACT = SUBSCRIBE, the USART receives the response
̶Wait until RXRDY in US_CSR rises
̶Read RCHR in US_RHR
̶If all the data have not been read, redo the two previous steps
̶Wait until LINTC in US_CSR rises
̶Check the LIN errors
Case 3: NACT = IGNORE, the USART is not concerned by the response
̶Wait until LINTC in US_CSR rises
̶Check the LIN errors
TXRDY
Write
US_LINIR
RXRDY
LINTC
BreakSynch Protected
Identifier Data 1 Data N Checksum
Data N-1
Header
Inter-
frame
space
Response
space
Frame
Frame slot = TFrame_Maximum
Response
Data3
FSDIS=1 FSDIS=0
_ [—22:31 T |_L|'| H. H H T _____ T T T _____ T _____ ‘I |_|J'L|'L|'L|'L|'| l—l_| l—I'I VIII-l l—H AtmeL
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Figure 35-49. Slave Node Configuration, NACT = PUBLISH
Figure 35-50. Slave Node Configuration, NACT = SUBSCRIBE
Figure 35-51. Slave Node Configuration, NACT = IGNORE
35.7.8.16 LIN Frame Handling With The PDC
The USART can be used in association with the PDC in order to transfer data directly into/from the on- and off-chip
memories without any processor intervention.
The PDC uses the trigger flags, TXRDY and RXRDY, to write or read into the USART. The PDC always writes in
the Transmit Holding register (US_THR) and it always reads in the Receive Holding register (US_RHR). The size
of the data written or read by the PDC in the USART is always a byte.
BreakSynch Protected
Identifier Data 1Data N Checksum
TXRDY
Write
US_THR
Read
US_LINID
Data 1Data 3
Data N-1
Data N
RXRDY
LINIDRX
Data 2
LINTC
TXRDY
Read
US_RHR
Read
US_LINID
RXRDY
LINIDRX
LINTC
BreakSynch Protected
Identifier Data 1Data N Checksum
Data 1
Data N-1
Data N-1 Data NData N-2
TXRDY
Read
US_RHR
Read
US_LINID
RXRDY
LINIDRX
LINTC
BreakSynch Protected
Identifier Data 1Data N ChecksumData N-1
AAAAA
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818
Master Node Configuration
The user can choose between two PDC modes by the PDCM bit in the LIN Mode register (US_LINMR):
PDCM = 1: the LIN configuration is stored in the WRITE buffer and it is written by the PDC in the Transmit
Holding register US_THR (instead of the LIN Mode register US_LINMR). Because the PDC transfer size is
limited to a byte, the transfer is split into two accesses. During the first access the bits, NACT, PARDIS,
CHKDIS, CHKTYP, DLM and FSDIS are written. During the second access the 8-bit DLC field is written.
PDCM = 0: the LIN configuration is not stored in the WRITE buffer and it must be written by the user in the
LIN Mode register (US_LINMR).
The WRITE buffer also contains the Identifier and the DATA, if the USART sends the response (NACT =
PUBLISH).
The READ buffer contains the DATA if the USART receives the response (NACT = SUBSCRIBE).
Figure 35-52. Master Node with PDC (PDCM = 1)
Figure 35-53. Master Node with PDC (PDCM = 0)
Slave Node Configuration
|
|
|
|
|
|
|
|
NACT
PARDIS
CHKDIS
CHKTYP
DLM
FSDIS
DLC
IDENTIFIER
DATA 0
DATA N
WRITE BUFFER
(Peripheral) DMA
Controller (Peripheral) DMA
Controller
USART3
LIN CONTROLLER
APB bus
NACT
PARDIS
CHKDIS
CHKTYP
DLM
FSDIS
DLC
IDENTIFIER
DATA 0
DATA N
WRITE BUFFER
RXRDY
TXRDY
TXRDY
USART3
LIN CONTROLLER
APB bus
READ BUFFER
NODE ACTION = PUBLISH NODE ACTION = SUBSCRIBE
|
|
|
|
RXRDY
TXRDY
TXRDY
APB bus
USART3
LIN CONTROLLER DATA 0
DATA N
|
|
|
|
WRITE BUFFER
USART3
LIN CONTROLLER
READ BUFFER
NODE ACTION = PUBLISH NODE ACTION = SUBSCRIBE
APB bus
IDENTIFIER
DATA 0
DATA N
WRITE BUFFER
IDENTIFIER
(Peripheral) DMA
Controller (Peripheral) DMA
Controller
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In this configuration, the PDC transfers only the DATA. The Identifier must be read by the user in the LIN Identifier
register (US_LINIR). The LIN mode must be written by the user in the LIN Mode register (US_LINMR).
The WRITE buffer contains the DATA if the USART sends the response (NACT=PUBLISH).
The READ buffer contains the DATA if the USART receives the response (NACT=SUBSCRIBE).
Figure 35-54. Slave Node with PDC
35.7.8.17 Wake-up Request
Any node in a sleeping LIN cluster may request a wake-up.
In the LIN 2.0 specification, the wakeup request is issued by forcing the bus to the dominant state from 250 µs to 5
ms. For this, it is necessary to send the character 0xF0 in order to impose 5 successive dominant bits. Whatever
the baud rate is, this character respects the specified timings.
Baud rate min = 1 kbit/s -> Tbit = 1ms -> 5 Tbits = 5 ms
Baud rate max = 20 kbit/s -> Tbi t= 50 µs -> 5 Tbits = 250 µs
In the LIN 1.3 specification, the wakeup request should be generated with the character 0x80 in order to impose 8
successive dominant bits.
The user can choose by the WKUPTYP bit in the LIN Mode register (US_LINMR) either to send a LIN 2.0 wakeup
request (WKUPTYP=0) or to send a LIN 1.3 wakeup request (WKUPTYP=1).
A wake-up request is transmitted by writing the Control Register (US_CR) with the LINWKUP bit to 1. Once the
transfer is completed, the LINTC flag is asserted in the Status Register (US_SR). It is cleared by writing the
Control Register (US_CR) with the RSTSTA bit to 1.
35.7.8.18 Bus Idle Time-out
If the LIN bus is inactive for a certain duration, the slave nodes shall automatically enter in sleep mode. In the LIN
2.0 specification, this time-out is fixed at 4 seconds. In the LIN 1.3 specification, it is fixed at 25000 Tbits.
In Slave Node configuration, the Receiver Time-out detects an idle condition on the RXD line. When a time-out is
detected, the bit TIMEOUT in the Channel Status Register (US_CSR) rises and can generate an interrupt, thus
indicating to the driver to go into sleep mode.
The time-out delay period (during which the receiver waits for a new character) is programmed in the TO field of
the Receiver Time-out Register (US_RTOR). If the TO field is programmed to 0, the Receiver Time-out is disabled
and no time-out is detected. The TIMEOUT bit in US_CSR remains to 0. Otherwise, the receiver loads a 17-bit
counter with the value programmed in TO. This counter is decremented at each bit period and reloaded each time
a new character is received. If the counter reaches 0, the TIMEOUT bit in the Status Register rises.
If STTTO is performed, the counter clock is stopped until a first character is received.
If RETTO is performed, the counter starts counting down immediately from the value TO.
|
|
|
|
|
|
|
|
DATA 0
DATA N
RXRDY
USART3
LIN CONTROLLER
APB bus
READ BUFFER
NACT = SUBSCRIBE
DATA 0
DATA N
TXRDY
USART3
LIN CONTROLLER
APB bus
WRITE BUFFER
(Peripheral) DMA
Controller (Peripheral) DMA
Controller
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35.7.9 Test Modes
The USART can be programmed to operate in three different test modes. The internal loopback capability allows
on-board diagnostics. In the loopback mode the USART interface pins are disconnected or not and reconfigured
for loopback internally or externally.
35.7.9.1 Normal Mode
Normal mode connects the RXD pin on the receiver input and the transmitter output on the TXD pin.
Figure 35-55. Normal Mode Configuration
35.7.9.2 Automatic Echo Mode
Automatic echo mode allows bit-by-bit retransmission. When a bit is received on the RXD pin, it is sent to the TXD
pin, as shown in Figure 35-56. Programming the transmitter has no effect on the TXD pin. The RXD pin is still
connected to the receiver input, thus the receiver remains active.
Figure 35-56. Automatic Echo Mode Configuration
Table 35-16. Receiver Time-out programming
LIN Specification Baud Rate Time-out period TO
2.0
1 000 bit/s
4s
4 000
2 400 bit/s 9 600
9 600 bit/s 38 400
19 200 bit/s 76 800
20 000 bit/s 80 000
1.3 - 25 000 Tbits 25 000
Receiver
Transmitter
RXD
TXD
Receiver
Transmitter
RXD
TXD
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35.7.9.3 Local Loopback Mode
Local loopback mode connects the output of the transmitter directly to the input of the receiver, as shown in Figure
35-57. The TXD and RXD pins are not used. The RXD pin has no effect on the receiver and the TXD pin is
continuously driven high, as in idle state.
Figure 35-57. Local Loopback Mode Configuration
35.7.9.4 Remote Loopback Mode
Remote loopback mode directly connects the RXD pin to the TXD pin, as shown in Figure 35-58. The transmitter
and the receiver are disabled and have no effect. This mode allows bit-by-bit retransmission.
Figure 35-58. Remote Loopback Mode Configuration
Receiver
Transmitter
RXD
TXD
1
Receiver
Transmitter
RXD
TXD
1
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35.7.10 Write Protection Registers
To prevent any single software error that may corrupt USART behavior, certain address spaces can be write-
protected by setting the WPEN bit in the USART Write Protect Mode Register (US_WPMR).
If a write access to the protected registers is detected, then the WPVS flag in the USART Write Protect Status
Register (US_WPSR) is set and the field WPVSRC indicates in which register the write access has been
attempted.
The WPVS flag is reset by writing the USART Write Protect Mode Register (US_WPMR) with the appropriate
access key, WPKEY.
The protected registers are:
“USART Mode Register”
“USART Baud Rate Generator Register”
“USART Receiver Time-out Register”
“USART Transmitter Timeguard Register”
“USART FI DI RATIO Register”
“USART IrDA FILTER Register”
“USART Manchester Configuration Register”
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35.8 Universal Synchronous Asynchronous Receiver Transmitter (USART) User Interface
Notes: 1. Write is possible only in LIN Master node configuration.
2. Values in the Version Register vary with the version of the IP block implementation.
Table 35-17. Register Mapping
Offset Register Name Access Reset
0x0000 Control Register US_CR Write-only –
0x0004 Mode Register US_MR Read-write –
0x0008 Interrupt Enable Register US_IER Write-only –
0x000C Interrupt Disable Register US_IDR Write-only –
0x0010 Interrupt Mask Register US_IMR Read-only 0x0
0x0014 Channel Status Register US_CSR Read-only –
0x0018 Receiver Holding Register US_RHR Read-only 0x0
0x001C Transmitter Holding Register US_THR Write-only –
0x0020 Baud Rate Generator Register US_BRGR Read-write 0x0
0x0024 Receiver Time-out Register US_RTOR Read-write 0x0
0x0028 Transmitter Timeguard Register US_TTGR Read-write 0x0
0x2C - 0x3C Reserved – – –
0x0040 FI DI Ratio Register US_FIDI Read-write 0x174
0x0044 Number of Errors Register US_NER Read-only –
0x0048 Reserved – – –
0x004C IrDA Filter Register US_IF Read-write 0x0
0x0050 Manchester Encoder Decoder Register US_MAN Read-write 0x30011004
0x0054 LIN Mode Register US_LINMR Read-write 0x0
0x0058 LIN Identifier Register US_LINIR Read-write(1) 0x0
0xE4 Write Protect Mode Register US_WPMR Read-write 0x0
0xE8 Write Protect Status Register US_WPSR Read-only 0x0
0x5C - 0xF8 Reserved – – –
0xFC Version Register US_VERSION Read-only 0x–(2)
0x100 - 0x128 Reserved for PDC Registers – – –
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35.8.1 USART Control Register
Name: US_CR
Address: 0x40098000 (0), 0x4009C000 (1), 0x400A0000 (2), 0x400A4000 (3)
Access: Write-only
• RSTRX: Reset Receiver
0: No effect.
1: Resets the receiver.
• RSTTX: Reset Transmitter
0: No effect.
1: Resets the transmitter.
• RXEN: Receiver Enable
0: No effect.
1: Enables the receiver, if RXDIS is 0.
• RXDIS: Receiver Disable
0: No effect.
1: Disables the receiver.
• TXEN: Transmitter Enable
0: No effect.
1: Enables the transmitter if TXDIS is 0.
• TXDIS: Transmitter Disable
0: No effect.
1: Disables the transmitter.
• RSTSTA: Reset Status Bits
0: No effect.
1: Resets the status bits PARE, FRAME, OVRE, MANERR, LINBE, LINISFE, LINIPE, LINCE, LINSNRE, LINID, LINTC,
LINBK, UNRE and RXBRK in US_CSR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– – LINWKUP LINABT RTSDIS/RCS RTSEN/FCS – –
15 14 13 12 11 10 9 8
RETTO RSTNACK RSTIT SENDA STTTO STPBRK STTBRK RSTSTA
76543210
TXDIS TXEN RXDIS RXEN RSTTX RSTRX – –
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• STTBRK: Start Break
0: No effect.
1: Starts transmission of a break after the characters present in US_THR and the Transmit Shift Register have been trans-
mitted. No effect if a break is already being transmitted.
• STPBRK: Stop Break
0: No effect.
1: Stops transmission of the break after a minimum of one character length and transmits a high level during 12-bit periods.
No effect if no break is being transmitted.
• STTTO: Start Time-out
0: No effect.
1: Starts waiting for a character before clocking the time-out counter. Resets the status bit TIMEOUT in US_CSR.
• SENDA: Send Address
0: No effect.
1: In Multidrop Mode only, the next character written to the US_THR is sent with the address bit set.
• RSTIT: Reset Iterations
0: No effect.
1: Resets ITERATION in US_CSR. No effect if the ISO7816 is not enabled.
• RSTNACK: Reset Non Acknowledge
0: No effect
1: Resets NACK in US_CSR.
• RETTO: Rearm Time-out
0: No effect
1: Restart Time-out
• RTSEN: Request to Send Enable
0: No effect.
1: Drives the pin RTS to 0.
• FCS: Force SPI Chip Select
– Applicable if USART operates in SPI Master Mode (USART_MODE = 0xE):
FCS = 0: No effect.
FCS = 1: Forces the Slave Select Line NSS (RTS pin) to 0, even if USART is no transmitting, in order to address SPI slave
devices supporting the CSAAT Mode (Chip Select Active After Transfer).
• RTSDIS: Request to Send Disable
0: No effect.
1: Drives the pin RTS to 1.
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• RCS: Release SPI Chip Select
– Applicable if USART operates in SPI Master Mode (USART_MODE = 0xE):
RCS = 0: No effect.
RCS = 1: Releases the Slave Select Line NSS (RTS pin).
• LINABT: Abort LIN Transmission
0: No effect.
1: Abort the current LIN transmission.
• LINWKUP: Send LIN Wakeup Signal
0: No effect:
1: Sends a wakeup signal on the LIN bus.
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35.8.2 USART Mode Register
Name: US_MR
Address: 0x40098004 (0), 0x4009C004 (1), 0x400A0004 (2), 0x400A4004 (3)
Access: Read-write
This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 854.
• USART_MODE
• USCLKS: Clock Selection
• CHRL: Character Length.
31 30 29 28 27 26 25 24
ONEBIT MODSYNC MAN FILTER – MAX_ITERATION
23 22 21 20 19 18 17 16
INVDATA VAR_SYNC DSNACK INACK OVER CLKO MODE9 MSBF/CPOL
15 14 13 12 11 10 9 8
CHMODE NBSTOP PAR SYNC/CPHA
76543210
CHRL USCLKS USART_MODE
Value Name Description
0x0 NORMAL Normal mode
0x1 RS485 RS485
0x2 HW_HANDSHAKING Hardware Handshaking
0x4 IS07816_T_0 IS07816 Protocol: T = 0
0x6 IS07816_T_1 IS07816 Protocol: T = 1
0x8 IRDA IrDA
0xA LIN_MASTER LIN Master
0xB LIN_SLAVE LIN Slave
0xE SPI_MASTER SPI Master
0xF SPI_SLAVE SPI Slave
Value Name Description
0 MCK Master Clock MCK is selected
1 DIV Internal Clock Divided MCK/DIV (DIV=8) is selected
3 SCK Serial Clock SLK is selected
Value Name Description
0 5_BIT Character length is 5 bits
1 6_BIT Character length is 6 bits
2 7_BIT Character length is 7 bits
3 8_BIT Character length is 8 bits
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• SYNC: Synchronous Mode Select
0: USART operates in Asynchronous Mode.
1: USART operates in Synchronous Mode.
• CPHA: SPI Clock Phase
– Applicable if USART operates in SPI Mode (USART_MODE = 0xE or 0xF):
CPHA = 0: Data is changed on the leading edge of SPCK and captured on the following edge of SPCK.
CPHA = 1: Data is captured on the leading edge of SPCK and changed on the following edge of SPCK.
CPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. CPHA is used
with CPOL to produce the required clock/data relationship between master and slave devices.
•PAR: Parity Type
• NBSTOP: Number of Stop Bits
• CHMODE: Channel Mode
•MSBF: Bit Order
0: Least Significant Bit is sent/received first.
1: Most Significant Bit is sent/received first.
• CPOL: SPI Clock Polarity
– Applicable if USART operates in SPI Mode (Slave or Master, USART_MODE = 0xE or 0xF):
CPOL = 0: The inactive state value of SPCK is logic level zero.
CPOL = 1: The inactive state value of SPCK is logic level one.
CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with CPHA to produce the required
clock/data relationship between master and slave devices.
Value Name Description
0 EVEN Even parity
1 ODD Odd parity
2 SPACE Parity forced to 0 (Space)
3 MARK Parity forced to 1 (Mark)
4NONo parity
6 MULTIDROP Multidrop mode
Value Name Description
0 1_BIT 1 stop bit
1 1_5_BIT 1.5 stop bit (SYNC = 0) or reserved (SYNC = 1)
2 2_BIT 2 stop bits
Value Name Description
0 NORMAL Normal Mode
1 AUTOMATIC Automatic Echo. Receiver input is connected to the TXD pin.
2 LOCAL_LOOPBACK Local Loopback. Transmitter output is connected to the Receiver Input.
3 REMOTE_LOOPBACK Remote Loopback. RXD pin is internally connected to the TXD pin.
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• MODE9: 9-bit Character Length
0: CHRL defines character length.
1: 9-bit character length.
• CLKO: Clock Output Select
0: The USART does not drive the SCK pin.
1: The USART drives the SCK pin if USCLKS does not select the external clock SCK.
• OVER: Oversampling Mode
0: 16x Oversampling.
1: 8x Oversampling.
• INACK: Inhibit Non Acknowledge
0: The NACK is generated.
1: The NACK is not generated.
Note: In SPI master mode, if INACK = 0 the character transmission starts as soon as a character is written into US_THR
register (assuming TXRDY was set). When INACK is 1, an additional condition must be met. The character transmission
starts when a character is written and only if RXRDY flag is cleared (Receiver Holding Register has been read).
• DSNACK: Disable Successive NACK
0: NACK is sent on the ISO line as soon as a parity error occurs in the received character (unless INACK is set).
1: Successive parity errors are counted up to the value specified in the MAX_ITERATION field. These parity errors gener-
ate a NACK on the ISO line. As soon as this value is reached, no additional NACK is sent on the ISO line. The flag
ITERATION is asserted.
• INVDATA: INverted Data
0: The data field transmitted on TXD line is the same as the one written in US_THR register or the content read in US_RHR
is the same as RXD line. Normal mode of operation.
1: The data field transmitted on TXD line is inverted (voltage polarity only) compared to the value written on US_THR reg-
ister or the content read in US_RHR is inverted compared to what is received on RXD line (or ISO7816 IO line). Inverted
Mode of operation, useful for contactless card application. To be used with configuration bit MSBF.
• VAR_SYNC: Variable Synchronization of Command/Data Sync Start Frame Delimiter
0: User defined configuration of command or data sync field depending on MODSYNC value.
1: The sync field is updated when a character is written into US_THR register.
• MAX_ITERATION
Defines the maximum number of iterations in mode ISO7816, protocol T= 0.
• FILTER: Infrared Receive Line Filter
0: The USART does not filter the receive line.
1: The USART filters the receive line using a three-sample filter (1/16-bit clock) (2 over 3 majority).
• MAN: Manchester Encoder/Decoder Enable
0: Manchester Encoder/Decoder are disabled.
1: Manchester Encoder/Decoder are enabled.
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
830
• MODSYNC: Manchester Synchronization Mode
0:The Manchester Start bit is a 0 to 1 transition
1: The Manchester Start bit is a 1 to 0 transition.
• ONEBIT: Start Frame Delimiter Selector
0: Start Frame delimiter is COMMAND or DATA SYNC.
1: Start Frame delimiter is One Bit.
AtmeL
831
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.3 USART Interrupt Enable Register
Name: US_IER
Address: 0x40098008 (0), 0x4009C008 (1), 0x400A0008 (2), 0x400A4008 (3)
Access: Write-only
0: No effect
1: Enables the corresponding interrupt.
• RXRDY: RXRDY Interrupt Enable
• TXRDY: TXRDY Interrupt Enable
• RXBRK: Receiver Break Interrupt Enable
• ENDRX: End of Receive Transfer Interrupt Enable
• ENDTX: End of Transmit Interrupt Enable
• OVRE: Overrun Error Interrupt Enable
• FRAME: Framing Error Interrupt Enable
• PARE: Parity Error Interrupt Enable
• TIMEOUT: Time-out Interrupt Enable
• TXEMPTY: TXEMPTY Interrupt Enable
• ITER: Max number of Repetitions Reached
• UNRE: SPI Underrun Error
• TXBUFE: Buffer Empty Interrupt Enable
• RXBUFF: Buffer Full Interrupt Enable
• NACK: Non Acknowledge Interrupt Enable
• LINBK: LIN Break Sent or LIN Break Received Interrupt Enable
• LINID: LIN Identifier Sent or LIN Identifier Received Interrupt Enable
31 30 29 28 27 26 25 24
– – LINSNRE LINCE LINIPE LINISFE LINBE MANE
23 22 21 20 19 18 17 16
– – – CTSIC – – –
15 14 13 12 11 10 9 8
LINTC LINID NACK/LINBK RXBUFF TXBUFE ITER/UNRE TXEMPTY TIMEOUT
76543210
PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
832
• LINTC: LIN Transfer Completed Interrupt Enable
• CTSIC: Clear to Send Input Change Interrupt Enable
• MANE: Manchester Error Interrupt Enable
• LINBE: LIN Bus Error Interrupt Enable
• LINISFE: LIN Inconsistent Synch Field Error Interrupt Enable
• LINIPE: LIN Identifier Parity Interrupt Enable
• LINCE: LIN Checksum Error Interrupt Enable
• LINSNRE: LIN Slave Not Responding Error Interrupt Enable
AtmeL
833
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.4 USART Interrupt Disable Register
Name: US_IDR
Address: 0x4009800C (0), 0x4009C00C (1), 0x400A000C (2), 0x400A400C (3)
Access: Write-only
0: No effect
1: Disables the corresponding interrupt.
• RXRDY: RXRDY Interrupt Disable
• TXRDY: TXRDY Interrupt Disable
• RXBRK: Receiver Break Interrupt Disable
• ENDRX: End of Receive Transfer Interrupt Disable
• ENDTX: End of Transmit Interrupt Disable
• OVRE: Overrun Error Interrupt Disable
• FRAME: Framing Error Interrupt Disable
• PARE: Parity Error Interrupt Disable
• TIMEOUT: Time-out Interrupt Disable
• TXEMPTY: TXEMPTY Interrupt Disable
• ITER: Max number of Repetitions Reached Disable
• UNRE: SPI Underrun Error Disable
• TXBUFE: Buffer Empty Interrupt Disable
• RXBUFF: Buffer Full Interrupt Disable
• NACK: Non Acknowledge Interrupt Disable
• LINBK: LIN Break Sent or LIN Break Received Interrupt Disable
• LINID: LIN Identifier Sent or LIN Identifier Received Interrupt Disable
31 30 29 28 27 26 25 24
– – LINSNRE LINCE LINIPE LINISFE LINBE MANE
23 22 21 20 19 18 17 16
– – – CTSIC – – –
15 14 13 12 11 10 9 8
LINTC LINID NACK/LINBK RXBUFF TXBUFE ITER/UNRE TXEMPTY TIMEOUT
76543210
PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
834
• LINTC: LIN Transfer Completed Interrupt Disable
• CTSIC: Clear to Send Input Change Interrupt Disable
• MANE: Manchester Error Interrupt Disable
• LINBE: LIN Bus Error Interrupt Disable
• LINISFE: LIN Inconsistent Synch Field Error Interrupt Disable
• LINIPE: LIN Identifier Parity Interrupt Disable
• LINCE: LIN Checksum Error Interrupt Disable
• LINSNRE: LIN Slave Not Responding Error Interrupt Disable
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835
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.5 USART Interrupt Mask Register
Name: US_IMR
Address: 0x40098010 (0), 0x4009C010 (1), 0x400A0010 (2), 0x400A4010 (3)
Access: Read-only
0: The corresponding interrupt is not enabled.
1: The corresponding interrupt is enabled.
• RXRDY: RXRDY Interrupt Mask
• TXRDY: TXRDY Interrupt Mask
• RXBRK: Receiver Break Interrupt Mask
• ENDRX: End of Receive Transfer Interrupt Mask
• ENDTX: End of Transmit Interrupt Mask
• OVRE: Overrun Error Interrupt Mask
• FRAME: Framing Error Interrupt Mask
• PARE: Parity Error Interrupt Mask
• TIMEOUT: Time-out Interrupt Mask
• TXEMPTY: TXEMPTY Interrupt Mask
• ITER: Max number of Repetitions Reached Mask
• UNRE: SPI Underrun Error Mask
• TXBUFE: Buffer Empty Interrupt Mask
• RXBUFF: Buffer Full Interrupt Mask
• NACK: Non Acknowledge Interrupt Mask
• LINBK: LIN Break Sent or LIN Break Received Interrupt Mask
• LINID: LIN Identifier Sent or LIN Identifier Received Interrupt Mask
31 30 29 28 27 26 25 24
– – LINSNRE LINCE LINIPE LINISFE LINBE MANE
23 22 21 20 19 18 17 16
– – – CTSIC – – –
15 14 13 12 11 10 9 8
LINTC LINID NACK/LINBK RXBUFF TXBUFE ITER/UNRE TXEMPTY TIMEOUT
76543210
PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
836
• LINTC: LIN Transfer Completed Interrupt Mask
• CTSIC: Clear to Send Input Change Interrupt Mask
• MANE: Manchester Error Interrupt Mask
• LINBE: LIN Bus Error Interrupt Mask
• LINISFE: LIN Inconsistent Synch Field Error Interrupt Mask
• LINIPE: LIN Identifier Parity Interrupt Mask
• LINCE: LIN Checksum Error Interrupt Mask
• LINSNRE: LIN Slave Not Responding Error Interrupt Mask
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837
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.6 USART Channel Status Register
Name: US_CSR
Address: 0x40098014 (0), 0x4009C014 (1), 0x400A0014 (2), 0x400A4014 (3)
Access: Read-only
• RXRDY: Receiver Ready
0: No complete character has been received since the last read of US_RHR or the receiver is disabled. If characters were
being received when the receiver was disabled, RXRDY changes to 1 when the receiver is enabled.
1: At least one complete character has been received and US_RHR has not yet been read.
• TXRDY: Transmitter Ready
0: A character is in the US_THR waiting to be transferred to the Transmit Shift Register, or an STTBRK command has
been requested, or the transmitter is disabled. As soon as the transmitter is enabled, TXRDY becomes 1.
1: There is no character in the US_THR.
• RXBRK: Break Received/End of Break
0: No Break received or End of Break detected since the last RSTSTA.
1: Break Received or End of Break detected since the last RSTSTA.
• ENDRX: End of Receiver Transfer
0: The End of Transfer signal from the Receive PDC channel is inactive.
1: The End of Transfer signal from the Receive PDC channel is active.
• ENDTX: End of Transmitter Transfer
0: The End of Transfer signal from the Transmit PDC channel is inactive.
1: The End of Transfer signal from the Transmit PDC channel is active.
• OVRE: Overrun Error
0: No overrun error has occurred since the last RSTSTA.
1: At least one overrun error has occurred since the last RSTSTA.
•FRAME: Framing Error
0: No stop bit has been detected low since the last RSTSTA.
1: At least one stop bit has been detected low since the last RSTSTA.
31 30 29 28 27 26 25 24
– – LINSNRE LINCE LINIPE LINISFE LINBE MANERR
23 22 21 20 19 18 17 16
CTS/LINBLS – – – CTSIC – – –
15 14 13 12 11 10 9 8
LINTC LINID NACK/LINBK RXBUFF TXBUFE ITER/UNRE TXEMPTY TIMEOUT
76543210
PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
838
• PARE: Parity Error
0: No parity error has been detected since the last RSTSTA.
1: At least one parity error has been detected since the last RSTSTA.
• TIMEOUT: Receiver Time-out
0: There has not been a time-out since the last Start Time-out command (STTTO in US_CR) or the Time-out Register is 0.
1: There has been a time-out since the last Start Time-out command (STTTO in US_CR).
• TXEMPTY: Transmitter Empty
0: There are characters in either US_THR or the Transmit Shift Register, or the transmitter is disabled.
1: There are no characters in US_THR, nor in the Transmit Shift Register.
• ITER: Max number of Repetitions Reached
0: Maximum number of repetitions has not been reached since the last RSTSTA.
1: Maximum number of repetitions has been reached since the last RSTSTA.
• UNRE: SPI Underrun Error
– Applicable if USART operates in SPI Slave Mode (USART_MODE = 0xF):
UNRE = 0: No SPI underrun error has occurred since the last RSTSTA.
UNRE = 1: At least one SPI underrun error has occurred since the last RSTSTA.
• TXBUFE: Transmission Buffer Empty
0: The signal Buffer Empty from the Transmit PDC channel is inactive.
1: The signal Buffer Empty from the Transmit PDC channel is active.
• RXBUFF: Reception Buffer Full
0: The signal Buffer Full from the Receive PDC channel is inactive.
1: The signal Buffer Full from the Receive PDC channel is active.
• NACK: Non Acknowledge Interrupt
0: Non Acknowledge has not been detected since the last RSTNACK.
1: At least one Non Acknowledge has been detected since the last RSTNACK.
• LINBK: LIN Break Sent or LIN Break Received
– Applicable if USART operates in LIN Master Mode (USART_MODE = 0xA):
0: No LIN Break has been sent since the last RSTSTA.
1: At least one LIN Break has been sent since the last RSTSTA
– If USART operates in LIN Slave Mode (USART_MODE = 0xB):
0: No LIN Break has received sent since the last RSTSTA.
1: At least one LIN Break has been received since the last RSTSTA.
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839
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• LINID: LIN Identifier Sent or LIN Identifier Received
–If USART operates in LIN Master Mode (USART_MODE = 0xA):
0: No LIN Identifier has been sent since the last RSTSTA.
1: At least one LIN Identifier has been sent since the last RSTSTA.
–If USART operates in LIN Slave Mode (USART_MODE = 0xB):
0: No LIN Identifier has been received since the last RSTSTA.
1: At least one LIN Identifier has been received since the last RSTSTA
• LINTC: LIN Transfer Completed
0: The USART is idle or a LIN transfer is ongoing.
1: A LIN transfer has been completed since the last RSTSTA.
• CTSIC: Clear to Send Input Change Flag
0: No input change has been detected on the CTS pin since the last read of US_CSR.
1: At least one input change has been detected on the CTS pin since the last read of US_CSR.
• CTS: Image of CTS Input
0: CTS is set to 0.
1: CTS is set to 1.
• LINBLS: LIN Bus Line Status
– Applicable if USART operates in LIN Mode (USART_MODE = 0xA or USART_MODE = 0xB):
0: LIN Bus Line is set to 0.
1: LIN Bus Line is set to 1.
• MANERR: Manchester Error
0: No Manchester error has been detected since the last RSTSTA.
1: At least one Manchester error has been detected since the last RSTSTA.
• LINBE: LIN Bit Error
0: No Bit Error has been detected since the last RSTSTA.
1: A Bit Error has been detected since the last RSTSTA.
• LINISFE: LIN Inconsistent Synch Field Error
0: No LIN Inconsistent Synch Field Error has been detected since the last RSTSTA
1: The USART is configured as a Slave node and a LIN Inconsistent Synch Field Error has been detected since the last
RSTSTA.
• LINIPE: LIN Identifier Parity Error
0: No LIN Identifier Parity Error has been detected since the last RSTSTA.
1: A LIN Identifier Parity Error has been detected since the last RSTSTA.
• LINCE: LIN Checksum Error
0: No LIN Checksum Error has been detected since the last RSTSTA.
1: A LIN Checksum Error has been detected since the last RSTSTA.
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
840
• LINSNRE: LIN Slave Not Responding Error
0: No LIN Slave Not Responding Error has been detected since the last RSTSTA.
1: A LIN Slave Not Responding Error has been detected since the last RSTSTA.
AtmeL
841
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.7 USART Receive Holding Register
Name: US_RHR
Address: 0x40098018 (0), 0x4009C018 (1), 0x400A0018 (2), 0x400A4018 (3)
Access: Read-only
• RXCHR: Received Character
Last character received if RXRDY is set.
• RXSYNH: Received Sync
0: Last Character received is a Data.
1: Last Character received is a Command.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
RXSYNH ––––––RXCHR
76543210
RXCHR
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
842
35.8.8 USART Transmit Holding Register
Name: US_THR
Address: 0x4009801C (0), 0x4009C01C (1), 0x400A001C (2), 0x400A401C (3)
Access: Write-only
• TXCHR: Character to be Transmitted
Next character to be transmitted after the current character if TXRDY is not set.
• TXSYNH: Sync Field to be transmitted
0: The next character sent is encoded as a data. Start Frame Delimiter is DATA SYNC.
1: The next character sent is encoded as a command. Start Frame Delimiter is COMMAND SYNC.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TXSYNH ––––––TXCHR
76543210
TXCHR
DE¢ AtmeL
843
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.9 USART Baud Rate Generator Register
Name: US_BRGR
Address: 0x40098020 (0), 0x4009C020 (1), 0x400A0020 (2), 0x400A4020 (3)
Access: Read-write
This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 854.
• CD: Clock Divider
• FP: Fractional Part
0: Fractional divider is disabled.
1 - 7: Baudrate resolution, defined by FP x 1/8.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––– FP
15 14 13 12 11 10 9 8
CD
76543210
CD
CD
USART_MODE ≠ ISO7816
USART_MODE =
ISO7816
SYNC = 0
SYNC = 1
or
USART_MODE = SPI
(Master or Slave)
OVER = 0 OVER = 1
0 Baud Rate Clock Disabled
1 to 65535 Baud Rate =
Selected Clock/(16*CD)
Baud Rate =
Selected Clock/(8*CD)
Baud Rate =
Selected Clock /CD
Baud Rate = Selected
Clock/(FI_DI_RATIO*CD)
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
844
35.8.10 USART Receiver Time-out Register
Name: US_RTOR
Address: 0x40098024 (0), 0x4009C024 (1), 0x400A0024 (2), 0x400A4024 (3)
Access: Read-write
This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 854.
• TO: Time-out Value
0: The Receiver Time-out is disabled.
1 - 131071: The Receiver Time-out is enabled and the Time-out delay is TO x Bit Period.
3130292827 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––––TO
15 14 13 12 11 10 9 8
TO
76543210
TO
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845
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.11 USART Transmitter Timeguard Register
Name: US_TTGR
Address: 0x40098028 (0), 0x4009C028 (1), 0x400A0028 (2), 0x400A4028 (3)
Access: Read-write
This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 854.
• TG: Timeguard Value
0: The Transmitter Timeguard is disabled.
1 - 255: The Transmitter timeguard is enabled and the timeguard delay is TG x Bit Period.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
TG
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
846
35.8.12 USART FI DI RATIO Register
Name: US_FIDI
Address: 0x40098040 (0), 0x4009C040 (1), 0x400A0040 (2), 0x400A4040 (3)
Access: Read-write
Reset Value: 0x174
This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 854.
• FI_DI_RATIO: FI Over DI Ratio Value
0: If ISO7816 mode is selected, the Baud Rate Generator generates no signal.
1 - 2047: If ISO7816 mode is selected, the Baud Rate is the clock provided on SCK divided by FI_DI_RATIO.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––– FI_DI_RATIO
76543210
FI_DI_RATIO
AtmeL
847
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.13 USART Number of Errors Register
Name: US_NER
Address: 0x40098044 (0), 0x4009C044 (1), 0x400A0044 (2), 0x400A4044 (3)
Access: Read-only
• NB_ERRORS: Number of Errors
Total number of errors that occurred during an ISO7816 transfer. This register automatically clears when read.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
NB_ERRORS
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
848
35.8.14 USART IrDA FILTER Register
Name: US_IF
Address: 0x4009804C (0), 0x4009C04C (1), 0x400A004C (2), 0x400A404C (3)
Access: Read-write
This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 854.
• IRDA_FILTER: IrDA Filter
Sets the filter of the IrDA demodulator.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
IRDA_FILTER
AtmeL
849
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.15 USART Manchester Configuration Register
Name: US_MAN
Address: 0x40098050 (0), 0x4009C050 (1), 0x400A0050 (2), 0x400A4050 (3)
Access: Read-write
This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 854.
• TX_PL: Transmitter Preamble Length
0: The Transmitter Preamble pattern generation is disabled
1 - 15: The Preamble Length is TX_PL x Bit Period
• TX_PP: Transmitter Preamble Pattern
The following values assume that TX_MPOL field is not set:
• TX_MPOL: Transmitter Manchester Polarity
0: Logic Zero is coded as a zero-to-one transition, Logic One is coded as a one-to-zero transition.
1: Logic Zero is coded as a one-to-zero transition, Logic One is coded as a zero-to-one transition.
• RX_PL: Receiver Preamble Length
0: The receiver preamble pattern detection is disabled
1 - 15: The detected preamble length is RX_PL x Bit Period
• RX_PP: Receiver Preamble Pattern detected
The following values assume that RX_MPOL field is not set:
31 30 29 28 27 26 25 24
–DRIFT1RX_MPOL– – RX_PP
23 22 21 20 19 18 17 16
–––– RX_PL
15 14 13 12 11 10 9 8
– – – TX_MPOL – – TX_PP
76543210
–––– TX_PL
Value Name Description
00 ALL_ONE The preamble is composed of ‘1’s
01 ALL_ZERO The preamble is composed of ‘0’s
10 ZERO_ONE The preamble is composed of ‘01’s
11 ONE_ZERO The preamble is composed of ‘10’s
Value Name Description
00 ALL_ONE The preamble is composed of ‘1’s
01 ALL_ZERO The preamble is composed of ‘0’s
10 ZERO_ONE The preamble is composed of ‘01’s
11 ONE_ZERO The preamble is composed of ‘10’s
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
850
• RX_MPOL: Receiver Manchester Polarity
0: Logic Zero is coded as a zero-to-one transition, Logic One is coded as a one-to-zero transition.
1: Logic Zero is coded as a one-to-zero transition, Logic One is coded as a zero-to-one transition.
• DRIFT: Drift compensation
0: The USART can not recover from an important clock drift
1: The USART can recover from clock drift. The 16X clock mode must be enabled.
AtmeL
851
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.16 USART LIN Mode Register
Name: US_LINMR
Address: 0x40098054 (0), 0x4009C054 (1), 0x400A0054 (2), 0x400A4054 (3)
Access: Read-write
• NACT: LIN Node Action
Values which are not listed in the table must be considered as “reserved”.
• PARDIS: Parity Disable
0: In Master node configuration, the Identifier Parity is computed and sent automatically. In Master node and Slave node
configuration, the parity is checked automatically.
1:Whatever the node configuration is, the Identifier parity is not computed/sent and it is not checked.
• CHKDIS: Checksum Disable
0: In Master node configuration, the checksum is computed and sent automatically. In Slave node configuration, the check-
sum is checked automatically.
1: Whatever the node configuration is, the checksum is not computed/sent and it is not checked.
• CHKTYP: Checksum Type
0: LIN 2.0 “Enhanced” Checksum
1: LIN 1.3 “Classic” Checksum
• DLM: Data Length Mode
0: The response data length is defined by the field DLC of this register.
1: The response data length is defined by the bits 5 and 6 of the Identifier (IDCHR in US_LINIR).
• FSDIS: Frame Slot Mode Disable
0: The Frame Slot Mode is enabled.
1: The Frame Slot Mode is disabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––––PDCM
15 14 13 12 11 10 9 8
DLC
76543210
WKUPTYP FSDIS DLM CHKTYP CHKDIS PARDIS NACT
Value Name Description
00 PUBLISH The USART transmits the response.
01 SUBSCRIBE The USART receives the response.
10 IGNORE The USART does not transmit and does not receive the response.
AtmeL
SAM3X / SAM3A [DATASHEET]
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852
• WKUPTYP: Wakeup Signal Type
0: setting the bit LINWKUP in the control register sends a LIN 2.0 wakeup signal.
1: setting the bit LINWKUP in the control register sends a LIN 1.3 wakeup signal.
• DLC: Data Length Control
0 - 255: Defines the response data length if DLM=0,in that case the response data length is equal to DLC+1 bytes.
• PDCM: PDC Mode
0: The LIN mode register US_LINMR is not written by the PDC.
1: The LIN mode register US_LINMR (excepting that flag) is written by the PDC.
AtmeL
853
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
35.8.17 USART LIN Identifier Register
Name: US_LINIR
Address: 0x40098058 (0), 0x4009C058 (1), 0x400A0058 (2), 0x400A4058 (3)
Access: Read-write or Read-only
• IDCHR: Identifier Character
If USART_MODE=0xA (Master node configuration):
IDCHR is Read-write and its value is the Identifier character to be transmitted.
if USART_MODE=0xB (Slave node configuration):
IDCHR is Read-only and its value is the last Identifier character that has been received.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
IDCHR
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
854
35.8.18 USART Write Protect Mode Register
Name: US_WPMR
Address: 0x400980E4 (0), 0x4009C0E4 (1), 0x400A00E4 (2), 0x400A40E4 (3)
Access: Read-write
Reset: See Table 35-17
• WPEN: Write Protect Enable
0 = Disables the Write Protect if WPKEY corresponds to 0x555341 (“USA” in ASCII).
1 = Enables the Write Protect if WPKEY corresponds to 0x555341 (“USA” in ASCII).
Protects the registers:
•“USART Mode Register” on page 827
•“USART Baud Rate Generator Register” on page 843
•“USART Receiver Time-out Register” on page 844
•“USART Transmitter Timeguard Register” on page 845
•“USART FI DI RATIO Register” on page 846
•“USART IrDA FILTER Register” on page 848
•“USART Manchester Configuration Register” on page 849
• WPKEY: Write Protect KEY
Should be written at value 0x555341 (“USA” in ASCII). Writing any other value in this field aborts the write operation of the
WPEN bit. Always reads as 0.
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
———————WPEN
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35.8.19 USART Write Protect Status Register
Name: US_WPSR
Address: 0x400980E8 (0), 0x4009C0E8 (1), 0x400A00E8 (2), 0x400A40E8 (3)
Access: Read-only
Reset: See Table 35-17
• WPVS: Write Protect Violation Status
0 = No Write Protect Violation has occurred since the last read of the US_WPSR register.
1 = A Write Protect Violation has occurred since the last read of the US_WPSR register. If this violation is an unauthorized
attempt to write a protected register, the associated violation is reported into field WPVSRC.
• WPVSRC: Write Protect Violation Source
When WPVS is active, this field indicates the write-protected register (through address offset or code) in which a write
access has been attempted.
Note: Reading US_WPSR automatically clears all fields.
31 30 29 28 27 26 25 24
————————
23 22 21 20 19 18 17 16
WPVSRC
15 14 13 12 11 10 9 8
WPVSRC
76543210
———————WPVS
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36. Timer Counter (TC)
36.1 Description
A Timer Counter (TC) module includes three identical TC channels. The number of implemented TC modules is
device-specific.
Each TC channel can be independently programmed to perform a wide range of functions including frequency
measurement, event counting, interval measurement, pulse generation, delay timing and pulse width modulation.
Each channel has three external clock inputs, five internal clock inputs and two multi-purpose input/output signals
which can be configured by the user. Each channel drives an internal interrupt signal which can be programmed to
generate processor interrupts.
The TC embeds a quadrature decoder (QDEC) connected in front of the timers and driven by TIOA0, TIOB0 and
TIOB1 inputs. When enabled, the QDEC performs the input lines filtering, decoding of quadrature signals and
connects to the timers/counters in order to read the position and speed of the motor through the user interface.
The TC block has two global registers which act upon all TC channels:
Block Control Register (TC_BCR)—allows channels to be started simultaneously with the same instruction
Block Mode Register (TC_BMR)—defines the external clock inputs for each channel, allowing them to be
chained
36.2 Embedded Characteristics
Total number of TC channels: 9
TC channel size: 32-bit
Wide range of functions including:
̶Frequency measurement
̶Event counting
̶Interval measurement
̶Pulse generation
̶Delay timing
̶Pulse Width Modulation
̶Up/down capabilities
̶Quadrature decoder
̶2-bit gray up/down count for stepper motor
Each channel is user-configurable and contains:
̶Three external clock inputs
̶Five Internal clock inputs
̶Two multi-purpose input/output signals acting as trigger event
Internal interrupt signal
Compare event fault generation for PWM
Register Write Protection
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36.3 Block Diagram
Note: 1. When SLCK is selected for Peripheral Clock (CSS = 0 in PMC Master Clock Register), SLCK input is equivalent
to Peripheral Clock.
Figure 36-1. Timer Counter Block Diagram
Note: The QDEC connections are detailed in Figure 36-15.
Table 36-1. Timer Counter Clock Assignment
Name Definition
TIMER_CLOCK1 MCK/2
TIMER_CLOCK2 MCK/8
TIMER_CLOCK3 MCK/32
TIMER_CLOCK4 MCK/128
TIMER_CLOCK5 SLCK
Timer/Counter
Channel 0
Timer/Counter
Channel 1
Timer/Counter
Channel 2
SYNC
Parallel I/O
Controller
TC1XC1S
TC0XC0S
TC2XC2S
INT0
INT1
INT2
TIOA0
TIOA1
TIOA2
TIOB0
TIOB1
TIOB2
XC0
XC1
XC2
XC0
XC1
XC2
XC0
XC1
XC2
TCLK0
TCLK1
TCLK2
TCLK0
TCLK1
TCLK2
TCLK0
TCLK1
TCLK2
TIOA1
TIOA2
TIOA0
TIOA2
TIOA0
TIOA1
Interrupt
Controller
TCLK0
TCLK1
TCLK2
TIOA0
TIOB0
TIOA1
TIOB1
TIOA2
TIOB2
Timer Counter
TIOA
TIOB
TIOA
TIOB
TIOA
TIOB
SYNC
SYNC
TIMER_CLOCK2
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
TIMER_CLOCK1
FAULT
PWM
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36.4 Pin Name List
36.5 Product Dependencies
36.5.1 I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines. The programmer
must first program the PIO controllers to assign the TC pins to their peripheral functions.
Table 36-2. Signal Name Description
Block/Channel Signal Name Description
Channel Signal
XC0, XC1, XC2 External Clock Inputs
TIOA Capture Mode: Timer Counter Input
Waveform Mode: Timer Counter Output
TIOB Capture Mode: Timer Counter Input
Waveform Mode: Timer Counter Input/Output
INT Interrupt Signal Output (internal signal)
SYNC Synchronization Input Signal (from configuration register)
Table 36-3. TC Pin List
Pin Name Description Type
TCLK0–TCLK2 External Clock Input Input
TIOA0–TIOA2 I/O Line A I/O
TIOB0–TIOB2 I/O Line B I/O
Table 36-4. I/O Lines
Instance Signal I/O Line Peripheral
TC0 TCLK0 PB26 B
TC0 TCLK1 PA4 A
TC0 TCLK2 PA7 A
TC0 TIOA0 PB25 B
TC0 TIOA1 PA2 A
TC0 TIOA2 PA5 A
TC0 TIOB0 PB27 B
TC0 TIOB1 PA3 A
TC0 TIOB2 PA6 A
TC1 TCLK3 PA22 B
TC1 TCLK4 PA23 B
TC1 TCLK5 PB16 A
TC1 TIOA3 PB0 B
TC1 TIOA3 PE9 A
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36.5.2 Power Management
The TC is clocked through the Power Management Controller (PMC), thus the programmer must first configure the
PMC to enable the Timer Counter clock.
36.5.3 Interrupt Sources
The TC has an interrupt line connected to the interrupt controller. Handling the TC interrupt requires programming
the interrupt controller before configuring the TC.
36.5.4 Fault Output
The TC has the FAULT output internally connected to the fault input of PWM. Refer to Section 36.6.16 ”Fault
Mode”, and to the implementation of the Pulse Width Modulation (PWM) in this product.
TC1 TIOA4 PB2 B
TC1 TIOA4 PE11 A
TC1 TIOA5 PB4 B
TC1 TIOA5 PE13 A
TC1 TIOB3 PB1 B
TC1 TIOB3 PE10 A
TC1 TIOB4 PB3 B
TC1 TIOB4 PE12 A
TC1 TIOB5 PB5 B
TC1 TIOB5 PE14 A
TC2 TCLK6 PC27 B
TC2 TCLK7 PC30 B
TC2 TCLK8 PD9 B
TC2 TIOA6 PC25 B
TC2 TIOA7 PC28 B
TC2 TIOA8 PD7 B
TC2 TIOB6 PC26 B
TC2 TIOB7 PC29 B
TC2 TIOB8 PD8 B
Table 36-4. I/O Lines (Continued)
Instance Signal I/O Line Peripheral
Table 36-5. Peripheral IDs
Instance ID
TC0 27
TC1 28
TC2 29
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36.6 Functional Description
36.6.1 Description
All channels of the Timer Counter are independent and identical in operation except when the QDEC is enabled.
The registers for channel programming are listed in Table 36-6 “Register Mapping”.
36.6.2 32-bit Counter
Each 32-bit channel is organized around a 32-bit counter. The value of the counter is incremented at each positive
edge of the selected clock. When the counter has reached the value 232-1 and passes to zero, an overflow occurs
and the COVFS bit in the TC Status Register (TC_SR) is set.
The current value of the counter is accessible in real time by reading the TC Counter Value Register (TC_CV). The
counter can be reset by a trigger. In this case, the counter value passes to zero on the next valid edge of the
selected clock.
36.6.3 Clock Selection
At block level, input clock signals of each channel can either be connected to the external inputs TCLK0, TCLK1 or
TCLK2, or be connected to the internal I/O signals TIOA0, TIOA1 or TIOA2 for chaining by programming the TC
Block Mode Register (TC_BMR). See Figure 36-2.
Each channel can independently select an internal or external clock source for its counter:
External clock signals(1): XC0, XC1 or XC2
Internal clock signals: MCK/2, MCK/8, MCK/32, MCK/128, SLCK
This selection is made by the TCCLKS bits in the TC Channel Mode Register (TC_CMR).
The selected clock can be inverted with the CLKI bit in the TC_CMR. This allows counting on the opposite edges
of the clock.
The burst function allows the clock to be validated when an external signal is high. The BURST parameter in the
TC_CMR defines this signal (none, XC0, XC1, XC2). See Figure 36-3.
Note: 1. In all cases, if an external clock is used, the duration of each of its levels must be longer than the peripheral clock
period. The external clock frequency must be at least 2.5 times lower than the peripheral clock.
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Figure 36-2. Clock Chaining Selection
Figure 36-3. Clock Selection
Timer/Counter
Channel 0
SYNC
TC0XC0S
TIOA0
TIOB0
XC0
XC1 = TCLK1
XC2 = TCLK2
TCLK0
TIOA1
TIOA2
Timer/Counter
Channel 1
SYNC
TC1XC1S
TIOA1
TIOB1
XC0 = TCLK0
XC1
XC2 = TCLK2
TCLK1
TIOA0
TIOA2
Timer/Counter
Channel 2
SYNC
TC2XC2S
TIOA2
TIOB2
XC0 = TCLK0
XC1 = TCLK1
XC2
TCLK2
TIOA0
TIOA1
TIMER_CLOCK1
TIMER_CLOCK2
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
XC0
XC1
XC2
TCCLKS
CLKI
Synchronous
Edge Detection
BURST
Peripheral Clock
1
Selected
Clock
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36.6.4 Clock Control
The clock of each counter can be controlled in two different ways: it can be enabled/disabled and started/stopped.
See Figure 36-4.
The clock can be enabled or disabled by the user with the CLKEN and the CLKDIS commands in the TC
Channel Control Register (TC_CCR). In Capture mode it can be disabled by an RB load event if LDBDIS is
set to 1 in the TC_CMR. In Waveform mode, it can be disabled by an RC Compare event if CPCDIS is set to
1 in TC_CMR. When disabled, the start or the stop actions have no effect: only a CLKEN command in the
TC_CCR can re-enable the clock. When the clock is enabled, the CLKSTA bit is set in the TC_SR.
The clock can also be started or stopped: a trigger (software, synchro, external or compare) always starts
the clock. The clock can be stopped by an RB load event in Capture mode (LDBSTOP = 1 in TC_CMR) or
an RC compare event in Waveform mode (CPCSTOP = 1 in TC_CMR). The start and the stop commands
are effective only if the clock is enabled.
Figure 36-4. Clock Control
36.6.5 Operating Modes
Each channel can operate independently in two different modes:
Capture mode provides measurement on signals.
Waveform mode provides wave generation.
The TC operating mode is programmed with the WAVE bit in the TC_CMR.
In Capture mode, TIOA and TIOB are configured as inputs.
In Waveform mode, TIOA is always configured to be an output and TIOB is an output if it is not selected to be the
external trigger.
36.6.6 Trigger
A trigger resets the counter and starts the counter clock. Three types of triggers are common to both modes, and a
fourth external trigger is available to each mode.
Regardless of the trigger used, it will be taken into account at the following active edge of the selected clock. This
means that the counter value can be read differently from zero just after a trigger, especially when a low frequency
signal is selected as the clock.
QS
R
S
R
Q
CLKSTA CLKEN CLKDIS
Stop
Event Disable
Event
Counter
Clock
Selected
Clock Trigger
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The following triggers are common to both modes:
Software Trigger: Each channel has a software trigger, available by setting SWTRG in TC_CCR.
SYNC: Each channel has a synchronization signal SYNC. When asserted, this signal has the same effect as
a software trigger. The SYNC signals of all channels are asserted simultaneously by writing TC_BCR (Block
Control) with SYNC set.
Compare RC Trigger: RC is implemented in each channel and can provide a trigger when the counter value
matches the RC value if CPCTRG is set in the TC_CMR.
The channel can also be configured to have an external trigger. In Capture mode, the external trigger signal can be
selected between TIOA and TIOB. In Waveform mode, an external event can be programmed on one of the
following signals: TIOB, XC0, XC1 or XC2. This external event can then be programmed to perform a trigger by
setting bit ENETRG in the TC_CMR.
If an external trigger is used, the duration of the pulses must be longer than the peripheral clock period in order to
be detected.
36.6.7 Capture Mode
Capture mode is entered by clearing the WAVE bit in the TC_CMR.
Capture mode allows the TC channel to perform measurements such as pulse timing, frequency, period, duty
cycle and phase on TIOA and TIOB signals which are considered as inputs.
Figure 36-5 shows the configuration of the TC channel when programmed in Capture mode.
36.6.8 Capture Registers A and B
Registers A and B (RA and RB) are used as capture registers. They can be loaded with the counter value when a
programmable event occurs on the signal TIOA.
The LDRA field in the TC_CMR defines the TIOA selected edge for the loading of register A, and the LDRB field
defines the TIOA selected edge for the loading of Register B.
RA is loaded only if it has not been loaded since the last trigger or if RB has been loaded since the last loading of
RA.
RB is loaded only if RA has been loaded since the last trigger or the last loading of RB.
Loading RA or RB before the read of the last value loaded sets the Overrun Error Flag (LOVRS bit) in the TC_SR.
In this case, the old value is overwritten.
36.6.9 Trigger Conditions
In addition to the SYNC signal, the software trigger and the RC compare trigger, an external trigger can be defined.
The ABETRG bit in the TC_CMR selects TIOA or TIOB input signal as an external trigger . The External Trigger
Edge Selection parameter (ETRGEDG field in TC_CMR) defines the edge (rising, falling, or both) detected to
generate an external trigger. If ETRGEDG = 0 (none), the external trigger is disabled.
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Figure 36-5. Capture Mode
TIMER_CLOCK1
TIMER_CLOCK2
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
XC0
XC1
XC2
TCCLKS
CLKI
QS
R
S
R
Q
CLKSTA CLKEN CLKDIS
BURST
TIOB
Register C
Capture
Register A Capture
Register B Compare RC =
Counter
ABETRG
SWTRG
ETRGEDG CPCTRG
TC1_IMR
Trig
LDRBS
LDRAS
ETRGS
TC1_SR
LOVRS
COVFS
SYNC
1
MTIOB
TIOA
MTIOA
LDRA
LDBSTOP
If RA is not loaded
or RB is Loaded If RA is Loaded
LDBDIS
CPCS
INT
Edge
Detector
Edge
Detector
LDRB
Edge
Detector
CLK OVF
RESET
Timer/Counter Channel
Peripheral Clock
Synchronous
Edge Detection
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36.6.10 Waveform Mode
Waveform mode is entered by setting the TC_CMRx.WAVE bit.
In Waveform mode, the TC channel generates one or two PWM signals with the same frequency and
independently programmable duty cycles, or generates different types of one-shot or repetitive pulses.
In this mode, TIOA is configured as an output and TIOB is defined as an output if it is not used as an external event
(EEVT parameter in TC_CMR).
Figure 36-6 shows the configuration of the TC channel when programmed in Waveform operating mode.
36.6.11 Waveform Selection
Depending on the WAVSEL parameter in TC_CMR, the behavior of TC_CV varies.
With any selection, TC_RA, TC_RB and TC_RC can all be used as compare registers.
RA Compare is used to control the TIOA output, RB Compare is used to control the TIOB output (if correctly
configured) and RC Compare is used to control TIOA and/or TIOB outputs.
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Figure 36-6. Waveform Mode
TCCLKS
CLKI
QS
R
S
R
Q
CLKSTA CLKEN CLKDIS
CPCDIS
BURST
TIOB
Register A Register B Register C
Compare RA = Compare RB = Compare RC =
CPCSTOP
Counter
EEVT
EEVTEDG
SYNC
SWTRG
ENETRG
WAVSEL
TC1_IMR
Trig
ACPC
ACPA
AEEVT
ASWTRG
BCPC
BCPB
BEEVT
BSWTRG
TIOA
MTIOA
TIOB
MTIOB
CPAS
COVFS
ETRGS
TC1_SR
CPCS
CPBS
CLK
OVF
RESET
Output Controller Output Controller
INT
1
Edge
Detector
Timer/Counter Channel
TIMER_CLOCK1
TIMER_CLOCK2
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
XC0
XC1
XC2
WAVSEL
Peripheral Clock
Synchronous
Edge Detection
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36.6.11.1 WAVSEL = 00
When WAVSEL = 00, the value of TC_CV is incremented from 0 to 232-1. Once 232-1 has been reached, the value
of TC_CV is reset. Incrementation of TC_CV starts again and the cycle continues. See Figure 36-7.
An external event trigger or a software trigger can reset the value of TC_CV. It is important to note that the trigger
may occur at any time. See Figure 36-8.
RC Compare cannot be programmed to generate a trigger in this configuration. At the same time, RC Compare
can stop the counter clock (CPCSTOP = 1 in TC_CMR) and/or disable the counter clock (CPCDIS = 1 in
TC_CMR).
Figure 36-7. WAVSEL = 00 without trigger
Figure 36-8. WAVSEL = 00 with Trigger
Time
Counter Value
RC
RB
RA
TIOB
TIOA
Counter cleared by compare match with 0xFFFF
0xFFFF
Waveform Examples
Time
Counter Value
R
C
R
B
R
A
TIOB
TIOA
Counter cleared by compare match with 0xFFFF
0xFFFF
Waveform Examples
Counter cleared by trigger
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36.6.11.2 WAVSEL = 10
When WAVSEL = 10, the value of TC_CV is incremented from 0 to the value of RC, then automatically reset on a
RC Compare. Once the value of TC_CV has been reset, it is then incremented and so on. See Figure 36-9.
It is important to note that TC_CV can be reset at any time by an external event or a software trigger if both are
programmed correctly. See Figure 36-10.
In addition, RC Compare can stop the counter clock (CPCSTOP = 1 in TC_CMR) and/or disable the counter clock
(CPCDIS = 1 in TC_CMR).
Figure 36-9. WAVSEL = 10 without Trigger
Figure 36-10. WAVSEL = 10 with Trigger
Time
Counter Value
RC
RB
RA
TIOB
TIOA
Counter cleared by compare match with RC
Waveform Examples
2n-1
(n = counter size)
Time
Counter Value
R
C
R
B
R
A
TIOB
TIOA
Counter cleared by compare match with RC
Waveform Examples
Counter cleared by trigger
2n-1
(n = counter size)
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36.6.11.3 WAVSEL = 01
When WAVSEL = 01, the value of TC_CV is incremented from 0 to 232-1 . Once 232-1 is reached, the value of
TC_CV is decremented to 0, then re-incremented to 232-1 and so on. See Figure 36-11.
A trigger such as an external event or a software trigger can modify TC_CV at any time. If a trigger occurs while
TC_CV is incrementing, TC_CV then decrements. If a trigger is received while TC_CV is decrementing, TC_CV
then increments. See Figure 36-12.
RC Compare cannot be programmed to generate a trigger in this configuration.
At the same time, RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the counter clock
(CPCDIS = 1).
Figure 36-11. WAVSEL = 01 without Trigger
Figure 36-12. WAVSEL = 01 with Trigger
Time
Counter Value
RC
RB
RA
TIOB
TIOA
Counter decremented by compare match with 0xFFFF
0xFFFF
Waveform Examples
Time
Counter Value
TIOB
TIOA
Counter decremented by compare match with 0xFFFF
0xFFFF
Waveform Examples
Counter decremented
by trigger
Counter incremented
by trigger
RC
RB
RA
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36.6.11.4 WAVSEL = 11
When WAVSEL = 11, the value of TC_CV is incremented from 0 to RC. Once RC is reached, the value of TC_CV
is decremented to 0, then re-incremented to RC and so on. See Figure 36-13.
A trigger such as an external event or a software trigger can modify TC_CV at any time. If a trigger occurs while
TC_CV is incrementing, TC_CV then decrements. If a trigger is received while TC_CV is decrementing, TC_CV
then increments. See Figure 36-14.
RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the counter clock (CPCDIS = 1).
Figure 36-13. WAVSEL = 11 without Trigger
Figure 36-14. WAVSEL = 11 with Trigger
Time
Counter Value
RC
RB
RA
TIOB
TIOA
Counter decremented by compare match with RC
Waveform Examples
2n-1
(n = counter size)
Time
Counter Value
TIOB
TIOA
Counter decremented by compare match with RC
Waveform Examples
Counter decremented
by trigger
Counter incremented
by trigger
RC
RB
RA
2n-1
(n = counter size)
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36.6.12 External Event/Trigger Conditions
An external event can be programmed to be detected on one of the clock sources (XC0, XC1, XC2) or TIOB. The
external event selected can then be used as a trigger.
The EEVT parameter in TC_CMR selects the external trigger. The EEVTEDG parameter defines the trigger edge
for each of the possible external triggers (rising, falling or both). If EEVTEDG is cleared (none), no external event
is defined.
If TIOB is defined as an external event signal (EEVT = 0), TIOB is no longer used as an output and the compare
register B is not used to generate waveforms and subsequently no IRQs. In this case the TC channel can only
generate a waveform on TIOA.
When an external event is defined, it can be used as a trigger by setting bit ENETRG in the TC_CMR.
As in Capture mode, the SYNC signal and the software trigger are also available as triggers. RC Compare can
also be used as a trigger depending on the parameter WAVSEL.
36.6.13 Output Controller
The output controller defines the output level changes on TIOA and TIOB following an event. TIOB control is used
only if TIOB is defined as output (not as an external event).
The following events control TIOA and TIOB: software trigger, external event and RC compare. RA compare
controls TIOA and RB compare controls TIOB. Each of these events can be programmed to set, clear or toggle the
output as defined in the corresponding parameter in TC_CMR.
36.6.14 Quadrature Decoder
36.6.14.1 Description
The quadrature decoder (QDEC) is driven by TIOA0, TIOB0, TIOB1 input pins and drives the timer/counter of
channel 0 and 1. Channel 2 can be used as a time base in case of speed measurement requirements (refer to
Figure 36-15).
When writing a 0 to bit QDEN of the TC_BMR, the QDEC is bypassed and the IO pins are directly routed to the
timer counter function. See
TIOA0 and TIOB0 are to be driven by the two dedicated quadrature signals from a rotary sensor mounted on the
shaft of the off-chip motor.
A third signal from the rotary sensor can be processed through pin TIOB1 and is typically dedicated to be driven by
an index signal if it is provided by the sensor. This signal is not required to decode the quadrature signals PHA,
PHB.
Field TCCLKS of TC_CMRx must be configured to select XC0 input (i.e., 0x101). Field TC0XC0S has no effect as
soon as the QDEC is enabled.
Either speed or position/revolution can be measured. Position channel 0 accumulates the edges of PHA, PHB
input signals giving a high accuracy on motor position whereas channel 1 accumulates the index pulses of the
sensor, therefore the number of rotations. Concatenation of both values provides a high level of precision on
motion system position.
In Speed mode, position cannot be measured but revolution can be measured.
Inputs from the rotary sensor can be filtered prior to down-stream processing. Accommodation of input polarity,
phase definition and other factors are configurable.
Interruptions can be generated on different events.
A compare function (using TC_RC) is available on channel 0 (speed/position) or channel 1 (rotation) and can
generate an interrupt by means of the CPCS flag in the TC_SRx.
| | <——> AtmeL
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Figure 36-15. Predefined Connection of the Quadrature Decoder with Timer Counters
36.6.14.2 Input Pre-processing
Input pre-processing consists of capabilities to take into account rotary sensor factors such as polarities and phase
definition followed by configurable digital filtering.
Each input can be negated and swapping PHA, PHB is also configurable.
The MAXFILT field in the TC_BMR is used to configure a minimum duration for which the pulse is stated as valid.
When the filter is active, pulses with a duration lower than MAXFILT +1 ×tperipheral clock ns are not passed to down-
stream logic.
Timer/Counter
Channel 0
1
XC0
TIOA
TIOB
Timer/Counter
Channel 1
1
XC0
TIOB
QDEN
Timer/Counter
Channel 2
1
TIOB0
XC0
1
1
SPEEDEN
1
XC0
Quadrature
Decoder
(Filter + Edge
Detect + QD)
PHA
PHB
IDX
TIOA0
TIOB0
TIOB1
TIOB1
TIOA0
Index
Speed/Position
Rotation
Speed Time Base
Reset pulse
Direction
PHEdges QDEN
+D_.*A
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Figure 36-16. Input Stage
Input filtering can efficiently remove spurious pulses that might be generated by the presence of particulate
contamination on the optical or magnetic disk of the rotary sensor.
Spurious pulses can also occur in environments with high levels of electro-magnetic interference. Or, simply if
vibration occurs even when rotation is fully stopped and the shaft of the motor is in such a position that the
beginning of one of the reflective or magnetic bars on the rotary sensor disk is aligned with the light or magnetic
(Hall) receiver cell of the rotary sensor. Any vibration can make the PHA, PHB signals toggle for a short duration.
1
1
1
MAXFILT
PHA
PHB
IDX
TIOA0
TIOB0
TIOB1
INVA
1
INVB
1
INVIDX
SWAP
1
IDXPHB
Filter
Filter
Filter
1
Direction
and
Edge
Detection
IDX
PHedge
DIR
Input Pre-Processing
MAXFILT > 0
> >4 < ‘="" ‘="">
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874
Figure 36-17. Filtering Examples
PHA,B
Filter Out
Peripheral Clock MAXFILT = 2
particulate contamination
PHA
PHB
motor shaft stopped in such a position that
rotary sensor cell is aligned with an edge of the disk
rotation
PHA
PHB
PHB Edge area due to system vibration
Resulting PHA, PHB electrical waveforms
PHA
Optical/Magnetic disk strips
stop
PHB
mechanical shock on system
vibration
stop
PHA, PHB electrical waveforms after filtering
PHA
PHB
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36.6.14.3 Direction Status and Change Detection
After filtering, the quadrature signals are analyzed to extract the rotation direction and edges of the two quadrature
signals detected in order to be counted by timer/counter logic downstream.
The direction status can be directly read at anytime in the TC_QISR. The polarity of the direction flag status
depends on the configuration written in TC_BMR. INVA, INVB, INVIDX, SWAP modify the polarity of DIR flag.
Any change in rotation direction is reported in the TC_QISR and can generate an interrupt.
The direction change condition is reported as soon as two consecutive edges on a phase signal have sampled the
same value on the other phase signal and there is an edge on the other signal. The two consecutive edges of one
phase signal sampling the same value on other phase signal is not sufficient to declare a direction change, for the
reason that particulate contamination may mask one or more reflective bars on the optical or magnetic disk of the
sensor. Refer to Figure 36-18 for waveforms.
Figure 36-18. Rotation Change Detection
The direction change detection is disabled when QDTRANS is set in the TC_BMR. In this case, the DIR flag report
must not be used.
A quadrature error is also reported by the QDEC via the QERR flag in the TC_QISR. This error is reported if the
time difference between two edges on PHA, PHB is lower than a predefined value. This predefined value is
PHA
PHB
Direction Change under normal conditions
DIR
DIRCHG
change condition
Report Time
No direction change due to particulate contamination masking a reflective bar
PHA
PHB
DIR
DIRCHG
spurious change condition (if detected in a simple way)
same phase
missing pulse
—|—_ —|_ a“\ F AtmeL
SAM3X / SAM3A [DATASHEET]
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876
configurable and corresponds to (MAXFILT + 1) × tperipheral clock ns. After being filtered there is no reason to have
two edges closer than (MAXFILT + 1) × tperipheral clock ns under normal mode of operation.
Figure 36-19. Quadrature Error Detection
MAXFILT must be tuned according to several factors such as the peripheral clock frequency, type of rotary sensor
and rotation speed to be achieved.
36.6.14.4 Position and Rotation Measurement
When the POSEN bit is set in the TC_BMR, the motor axis position is processed on channel 0 (by means of the
PHA, PHB edge detections) and the number of motor revolutions are recorded on channel 1 if the IDX signal is
provided on the TIOB1 input. The position measurement can be read in the TC_CV0 register and the rotation
measurement can be read in the TC_CV1 register.
Channel 0 and 1 must be configured in Capture mode (TC_CMR0.WAVE = 0). ‘Rising edge’ must be selected as
the External Trigger Edge (TC_CMR.ETRGEDG = 0x01) and ‘TIOA’ must be selected as the External Trigger
(TC_CMR.ABETRG = 0x1).
In parallel, the number of edges are accumulated on timer/counter channel 0 and can be read on the TC_CV0
register.
Therefore, the accurate position can be read on both TC_CV registers and concatenated to form a 32-bit word.
The timer/counter channel 0 is cleared for each increment of IDX count value.
Peripheral Clock MAXFILT = 2
PHA
PHB
A
bnormally formatted optical disk strips (theoretical view)
PHA
PHB
strip edge inaccurary due to disk etching/printing process
resulting PHA, PHB electrical waveforms
PHA
PHB
Even with an abnorrmaly formatted disk, there is no occurence of PHA, PHB switching at the same time.
QERR
duration < MAXFILT
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Depending on the quadrature signals, the direction is decoded and allows to count up or down in timer/counter
channels 0 and 1. The direction status is reported on TC_QISR.
36.6.14.5 Speed Measurement
When SPEEDEN is set in the TC_BMR, the speed measure is enabled on channel 0.
A time base must be defined on channel 2 by writing the TC_RC2 period register. Channel 2 must be configured in
Waveform mode (WAVE bit set) in TC_CMR2. The WAVSEL field must be defined with 0x10 to clear the counter
by comparison and matching with TC_RC value. Field ACPC must be defined at 0x11 to toggle TIOA output.
This time base is automatically fed back to TIOA of channel 0 when QDEN and SPEEDEN are set.
Channel 0 must be configured in Capture mode (WAVE = 0 in TC_CMR0). The ABETRG bit of TC_CMR0 must be
configured at 1 to select TIOA as a trigger for this channel.
EDGTRG must be set to 0x01, to clear the counter on a rising edge of the TIOA signal and field LDRA must be set
accordingly to 0x01, to load TC_RA0 at the same time as the counter is cleared (LDRB must be set to 0x01). As a
consequence, at the end of each time base period the differentiation required for the speed calculation is
performed.
The process must be started by configuring bits CLKEN and SWTRG in the TC_CCR.
The speed can be read on field RA in TC_RA0.
Channel 1 can still be used to count the number of revolutions of the motor.
36.6.15 2-bit Gray Up/Down Counter for Stepper Motor
Each channel can be independently configured to generate a 2-bit gray count waveform on corresponding TIOA,
TIOB outputs by means of the GCEN bit in TC_SMMRx.
Up or Down count can be defined by writing bit DOWN in TC_SMMRx.
It is mandatory to configure the channel in Waveform mode in the TC_CMR.
The period of the counters can be programmed in TC_RCx.
Figure 36-20. 2-bit Gray Up/Down Counter
TIOAx
TIOBx
DOWNx
TC_RCx
WAVEx = GCENx =1
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36.6.16 Fault Mode
At any time, the TC_RCx registers can be used to perform a comparison on the respective current channel counter
value (TC_CVx) with the value of TC_RCx register.
The CPCSx flags can be set accordingly and an interrupt can be generated.
This interrupt is processed but requires an unpredictable amount of time to be achieve the required action.
It is possible to trigger the FAULT output of the TIMER1 with CPCS from TC_SR0 and/or CPCS from TC_SR1.
Each source can be independently enabled/disabled in the TC_FMR.
This can be useful to detect an overflow on speed and/or position when QDEC is processed and to act
immediately by using the FAULT output.
Figure 36-21. Fault Output Generation
36.6.17 Register Write Protection
To prevent any single software error from corrupting TC behavior, certain registers in the address space can be
write-protected by setting the WPEN bit in the TC Write Protection Mode Register (TC_WPMR).
The Timer Counter clock of the first channel must be enabled to access TC_WPMR.
TC_SR0 flag CPCS
TC_FMR / ENCF0
FAULT (to PWM input)
OR
AND
AND
TC_SR1 flag CPCS
TC_FMR / ENCF1
The following registers can be write-protected:
TC Block Mode Register
TC Channel Mode Register: Capture Mode
TC Channel Mode Register: Waveform Mode
TC Fault Mode Register
TC Stepper Motor Mode Register
TC Register A
TC Register B
TC Register C
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36.7 Timer Counter (TC) User Interface
Notes: 1. Channel index ranges from 0 to 2.
2. Read-only if TC_CMRx.WAVE = 0
Table 36-6. Register Mapping
Offset(1) Register Name Access Reset
0x00 + channel * 0x40 + 0x00 Channel Control Register TC_CCR Write-only –
0x00 + channel * 0x40 + 0x04 Channel Mode Register TC_CMR Read/Write 0
0x00 + channel * 0x40 + 0x08 Stepper Motor Mode Register TC_SMMR Read/Write 0
0x00 + channel * 0x40 + 0x0C Reserved – – –
0x00 + channel * 0x40 + 0x10 Counter Value TC_CV Read-only 0
0x00 + channel * 0x40 + 0x14 Register A TC_RA Read/Write(2) 0
0x00 + channel * 0x40 + 0x18 Register B TC_RB Read/Write(2) 0
0x00 + channel * 0x40 + 0x1C Register C TC_RC Read/Write 0
0x00 + channel * 0x40 + 0x20 Status Register TC_SR Read-only 0
0x00 + channel * 0x40 + 0x24 Interrupt Enable Register TC_IER Write-only –
0x00 + channel * 0x40 + 0x28 Interrupt Disable Register TC_IDR Write-only –
0x00 + channel * 0x40 + 0x2C Interrupt Mask Register TC_IMR Read-only 0
0xC0 Block Control Register TC_BCR Write-only –
0xC4 Block Mode Register TC_BMR Read/Write 0
0xC8 QDEC Interrupt Enable Register TC_QIER Write-only –
0xCC QDEC Interrupt Disable Register TC_QIDR Write-only –
0xD0 QDEC Interrupt Mask Register TC_QIMR Read-only 0
0xD4 QDEC Interrupt Status Register TC_QISR Read-only 0
0xD8 Fault Mode Register TC_FMR Read/Write 0
0xE4 Write Protection Mode Register TC_WPMR Read/Write 0
0xE8–0xFC Reserved – – –
AtmeL
SAM3X / SAM3A [DATASHEET]
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880
36.7.1 TC Channel Control Register
Name: TC_CCRx [x=0..2]
Address: 0x40080000 (0)[0], 0x40080040 (0)[1], 0x40080080 (0)[2], 0x40084000 (1)[0], 0x40084040 (1)[1],
0x40084080 (1)[2], 0x40088000 (2)[0], 0x40088040 (2)[1], 0x40088080 (2)[2]
Access: Write-only
• CLKEN: Counter Clock Enable Command
0: No effect.
1: Enables the clock if CLKDIS is not 1.
• CLKDIS: Counter Clock Disable Command
0: No effect.
1: Disables the clock.
• SWTRG: Software Trigger Command
0: No effect.
1: A software trigger is performed: the counter is reset and the clock is started.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––SWTRGCLKDISCLKEN
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
36.7.2 TC Channel Mode Register: Capture Mode
Name: TC_CMRx [x=0..2] (CAPTURE_MODE)
Address: 0x40080004 (0)[0], 0x40080044 (0)[1], 0x40080084 (0)[2], 0x40084004 (1)[0], 0x40084044 (1)[1],
0x40084084 (1)[2], 0x40088004 (2)[0], 0x40088044 (2)[1], 0x40088084 (2)[2]
Access: Read/Write
This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.
• TCCLKS: Clock Selection
• CLKI: Clock Invert
0: Counter is incremented on rising edge of the clock.
1: Counter is incremented on falling edge of the clock.
• BURST: Burst Signal Selection
• LDBSTOP: Counter Clock Stopped with RB Loading
0: Counter clock is not stopped when RB loading occurs.
1: Counter clock is stopped when RB loading occurs.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––– LDRB LDRA
15 14 13 12 11 10 9 8
WAVE CPCTRG – – – ABETRG ETRGEDG
76543210
LDBDIS LDBSTOP BURST CLKI TCCLKS
Value Name Description
0 TIMER_CLOCK1 Clock selected: internal MCK/2 clock signal (from PMC)
1 TIMER_CLOCK2 Clock selected: internal MCK/8 clock signal (from PMC)
2 TIMER_CLOCK3 Clock selected: internal MCK/32 clock signal (from PMC)
3 TIMER_CLOCK4 Clock selected: internal MCK/128 clock signal (from PMC)
4 TIMER_CLOCK5 Clock selected: internal SLCK clock signal (from PMC)
5 XC0 Clock selected: XC0
6 XC1 Clock selected: XC1
7 XC2 Clock selected: XC2
Value Name Description
0 NONE The clock is not gated by an external signal.
1 XC0 XC0 is ANDed with the selected clock.
2 XC1 XC1 is ANDed with the selected clock.
3 XC2 XC2 is ANDed with the selected clock.
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882
• LDBDIS: Counter Clock Disable with RB Loading
0: Counter clock is not disabled when RB loading occurs.
1: Counter clock is disabled when RB loading occurs.
• ETRGEDG: External Trigger Edge Selection
• ABETRG: TIOA or TIOB External Trigger Selection
0: TIOB is used as an external trigger.
1: TIOA is used as an external trigger.
• CPCTRG: RC Compare Trigger Enable
0: RC Compare has no effect on the counter and its clock.
1: RC Compare resets the counter and starts the counter clock.
• WAVE: Waveform Mode
0: Capture mode is enabled.
1: Capture mode is disabled (Waveform mode is enabled).
• LDRA: RA Loading Edge Selection
• LDRB: RB Loading Edge Selection
Value Name Description
0 NONE The clock is not gated by an external signal.
1 RISING Rising edge
2 FALLING Falling edge
3 EDGE Each edge
Value Name Description
0 NONE None
1 RISING Rising edge of TIOA
2 FALLING Falling edge of TIOA
3 EDGE Each edge of TIOA
Value Name Description
0 NONE None
1 RISING Rising edge of TIOA
2 FALLING Falling edge of TIOA
3 EDGE Each edge of TIOA
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883
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
36.7.3 TC Channel Mode Register: Waveform Mode
Name: TC_CMRx [x=0..2] (WAVEFORM_MODE)
Access: Read/Write
This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.
• TCCLKS: Clock Selection
• CLKI: Clock Invert
0: Counter is incremented on rising edge of the clock.
1: Counter is incremented on falling edge of the clock.
• BURST: Burst Signal Selection
• CPCSTOP: Counter Clock Stopped with RC Compare
0: Counter clock is not stopped when counter reaches RC.
1: Counter clock is stopped when counter reaches RC.
31 30 29 28 27 26 25 24
BSWTRG BEEVT BCPC BCPB
23 22 21 20 19 18 17 16
ASWTRG AEEVT ACPC ACPA
15 14 13 12 11 10 9 8
WAVE WAVSEL ENETRG EEVT EEVTEDG
76543210
CPCDIS CPCSTOP BURST CLKI TCCLKS
Value Name Description
0 TIMER_CLOCK1 Clock selected: internal MCK/2 clock signal (from PMC)
1 TIMER_CLOCK2 Clock selected: internal MCK/8 clock signal (from PMC)
2 TIMER_CLOCK3 Clock selected: internal MCK/32 clock signal (from PMC)
3 TIMER_CLOCK4 Clock selected: internal MCK/128 clock signal (from PMC)
4 TIMER_CLOCK5 Clock selected: internal SLCK clock signal (from PMC)
5 XC0 Clock selected: XC0
6 XC1 Clock selected: XC1
7 XC2 Clock selected: XC2
Value Name Description
0 NONE The clock is not gated by an external signal.
1 XC0 XC0 is ANDed with the selected clock.
2 XC1 XC1 is ANDed with the selected clock.
3 XC2 XC2 is ANDed with the selected clock.
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• CPCDIS: Counter Clock Disable with RC Compare
0: Counter clock is not disabled when counter reaches RC.
1: Counter clock is disabled when counter reaches RC.
• EEVTEDG: External Event Edge Selection
• EEVT: External Event Selection
Signal selected as external event.
Note: 1. If TIOB is chosen as the external event signal, it is configured as an input and no longer generates waveforms and
subsequently no IRQs.
• ENETRG: External Event Trigger Enable
0: The external event has no effect on the counter and its clock.
1: The external event resets the counter and starts the counter clock.
Note: Whatever the value programmed in ENETRG, the selected external event only controls the TIOA output and TIOB if not used as
input (trigger event input or other input used).
• WAVSEL: Waveform Selection
• WAVE: Waveform Mode
0: Waveform mode is disabled (Capture mode is enabled).
1: Waveform mode is enabled.
• ACPA: RA Compare Effect on TIOA
Value Name Description
0 NONE None
1 RISING Rising edge
2 FALLING Falling edge
3 EDGE Each edge
Value Name Description TIOB Direction
0 TIOB TIOB(1) Input
1 XC0 XC0 Output
2 XC1 XC1 Output
3 XC2 XC2 Output
Value Name Description
0 UP UP mode without automatic trigger on RC Compare
1 UPDOWN UPDOWN mode without automatic trigger on RC Compare
2 UP_RC UP mode with automatic trigger on RC Compare
3 UPDOWN_RC UPDOWN mode with automatic trigger on RC Compare
Value Name Description
0 NONE None
1 SET Set
2 CLEAR Clear
3 TOGGLE Toggle
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• ACPC: RC Compare Effect on TIOA
• AEEVT: External Event Effect on TIOA
• ASWTRG: Software Trigger Effect on TIOA
• BCPB: RB Compare Effect on TIOB
• BCPC: RC Compare Effect on TIOB
• BEEVT: External Event Effect on TIOB
Value Name Description
0 NONE None
1 SET Set
2 CLEAR Clear
3 TOGGLE Toggle
Value Name Description
0 NONE None
1 SET Set
2 CLEAR Clear
3 TOGGLE Toggle
Value Name Description
0 NONE None
1 SET Set
2 CLEAR Clear
3 TOGGLE Toggle
Value Name Description
0 NONE None
1 SET Set
2 CLEAR Clear
3 TOGGLE Toggle
Value Name Description
0 NONE None
1 SET Set
2 CLEAR Clear
3 TOGGLE Toggle
Value Name Description
0 NONE None
1 SET Set
2 CLEAR Clear
3 TOGGLE Toggle
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886
• BSWTRG: Software Trigger Effect on TIOB
Value Name Description
0 NONE None
1 SET Set
2 CLEAR Clear
3 TOGGLE Toggle
AtmeL
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
36.7.4 TC Stepper Motor Mode Register
Name: TC_SMMRx [x=0..2]
Address: 0x40080008 (0)[0], 0x40080048 (0)[1], 0x40080088 (0)[2], 0x40084008 (1)[0], 0x40084048 (1)[1],
0x40084088 (1)[2], 0x40088008 (2)[0], 0x40088048 (2)[1], 0x40088088 (2)[2]
Access: Read/Write
This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.
• GCEN: Gray Count Enable
0: TIOAx [x=0..2] and TIOBx [x=0..2] are driven by internal counter of channel x.
1: TIOAx [x=0..2] and TIOBx [x=0..2] are driven by a 2-bit gray counter.
• DOWN: Down Count
0: Up counter.
1: Down counter.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––DOWNGCEN
AtmeL
SAM3X / SAM3A [DATASHEET]
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888
36.7.5 TC Counter Value Register
Name: TC_CVx [x=0..2]
Address: 0x40080010 (0)[0], 0x40080050 (0)[1], 0x40080090 (0)[2], 0x40084010 (1)[0], 0x40084050 (1)[1],
0x40084090 (1)[2], 0x40088010 (2)[0], 0x40088050 (2)[1], 0x40088090 (2)[2]
Access: Read-only
• CV: Counter Value
CV contains the counter value in real time.
31 30 29 28 27 26 25 24
CV
23 22 21 20 19 18 17 16
CV
15 14 13 12 11 10 9 8
CV
76543210
CV
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
36.7.6 TC Register A
Name: TC_RAx [x=0..2]
Address: 0x40080014 (0)[0], 0x40080054 (0)[1], 0x40080094 (0)[2], 0x40084014 (1)[0], 0x40084054 (1)[1],
0x40084094 (1)[2], 0x40088014 (2)[0], 0x40088054 (2)[1], 0x40088094 (2)[2]
Access: Read-only if TC_CMRx.WAVE = 0, Read/Write if TC_CMRx.WAVE = 1
This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.
• RA: Register A
RA contains the Register A value in real time.
31 30 29 28 27 26 25 24
RA
23 22 21 20 19 18 17 16
RA
15 14 13 12 11 10 9 8
RA
76543210
RA
AtmeL
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890
36.7.7 TC Register B
Name: TC_RBx [x=0..2]
Address: 0x40080018 (0)[0], 0x40080058 (0)[1], 0x40080098 (0)[2], 0x40084018 (1)[0], 0x40084058 (1)[1],
0x40084098 (1)[2], 0x40088018 (2)[0], 0x40088058 (2)[1], 0x40088098 (2)[2]
Access: Read-only if TC_CMRx.WAVE = 0, Read/Write if TC_CMRx.WAVE = 1
This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.
• RB: Register B
RB contains the Register B value in real time.
31 30 29 28 27 26 25 24
RB
23 22 21 20 19 18 17 16
RB
15 14 13 12 11 10 9 8
RB
76543210
RB
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
36.7.8 TC Register C
Name: TC_RCx [x=0..2]
Address: 0x4008001C (0)[0], 0x4008005C (0)[1], 0x4008009C (0)[2], 0x4008401C (1)[0], 0x4008405C (1)[1],
0x4008409C (1)[2], 0x4008801C (2)[0], 0x4008805C (2)[1], 0x4008809C (2)[2]
Access: Read/Write
This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.
• RC: Register C
RC contains the Register C value in real time.
31 30 29 28 27 26 25 24
RC
23 22 21 20 19 18 17 16
RC
15 14 13 12 11 10 9 8
RC
76543210
RC
AtmeL
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892
36.7.9 TC Status Register
Name: TC_SRx [x=0..2]
Address: 0x40080020 (0)[0], 0x40080060 (0)[1], 0x400800A0 (0)[2], 0x40084020 (1)[0], 0x40084060 (1)[1],
0x400840A0 (1)[2], 0x40088020 (2)[0], 0x40088060 (2)[1], 0x400880A0 (2)[2]
Access: Read-only
• COVFS: Counter Overflow Status (cleared on read)
0: No counter overflow has occurred since the last read of the Status Register.
1: A counter overflow has occurred since the last read of the Status Register.
• LOVRS: Load Overrun Status (cleared on read)
0: Load overrun has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 1.
1: RA or RB have been loaded at least twice without any read of the corresponding register since the last read of the Sta-
tus Register, if TC_CMRx.WAVE = 0.
• CPAS: RA Compare Status (cleared on read)
0: RA Compare has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 0.
1: RA Compare has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 1.
• CPBS: RB Compare Status (cleared on read)
0: RB Compare has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 0.
1: RB Compare has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 1.
• CPCS: RC Compare Status (cleared on read)
0: RC Compare has not occurred since the last read of the Status Register.
1: RC Compare has occurred since the last read of the Status Register.
• LDRAS: RA Loading Status (cleared on read)
0: RA Load has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 1.
1: RA Load has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 0.
• LDRBS: RB Loading Status (cleared on read)
0: RB Load has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 1.
1: RB Load has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 0.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––MTIOBMTIOACLKSTA
15 14 13 12 11 10 9 8
––––––––
76543210
ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS
AtmeL
893
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• ETRGS: External Trigger Status (cleared on read)
0: External trigger has not occurred since the last read of the Status Register.
1: External trigger has occurred since the last read of the Status Register.
• CLKSTA: Clock Enabling Status
0: Clock is disabled.
1: Clock is enabled.
• MTIOA: TIOA Mirror
0: TIOA is low. If TC_CMRx.WAVE = 0, this means that TIOA pin is low. If TC_CMRx.WAVE = 1, this means that TIOA is
driven low.
1: TIOA is high. If TC_CMRx.WAVE = 0, this means that TIOA pin is high. If TC_CMRx.WAVE = 1, this means that TIOA is
driven high.
• MTIOB: TIOB Mirror
0: TIOB is low. If TC_CMRx.WAVE = 0, this means that TIOB pin is low. If TC_CMRx.WAVE = 1, this means that TIOB is
driven low.
1: TIOB is high. If TC_CMRx.WAVE = 0, this means that TIOB pin is high. If TC_CMRx.WAVE = 1, this means that TIOB is
driven high.
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
894
36.7.10 TC Interrupt Enable Register
Name: TC_IERx [x=0..2]
Address: 0x40080024 (0)[0], 0x40080064 (0)[1], 0x400800A4 (0)[2], 0x40084024 (1)[0], 0x40084064 (1)[1],
0x400840A4 (1)[2], 0x40088024 (2)[0], 0x40088064 (2)[1], 0x400880A4 (2)[2]
Access: Write-only
• COVFS: Counter Overflow
0: No effect.
1: Enables the Counter Overflow Interrupt.
• LOVRS: Load Overrun
0: No effect.
1: Enables the Load Overrun Interrupt.
• CPAS: RA Compare
0: No effect.
1: Enables the RA Compare Interrupt.
• CPBS: RB Compare
0: No effect.
1: Enables the RB Compare Interrupt.
• CPCS: RC Compare
0: No effect.
1: Enables the RC Compare Interrupt.
• LDRAS: RA Loading
0: No effect.
1: Enables the RA Load Interrupt.
• LDRBS: RB Loading
0: No effect.
1: Enables the RB Load Interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS
AtmeL
895
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• ETRGS: External Trigger
0: No effect.
1: Enables the External Trigger Interrupt.
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
896
36.7.11 TC Interrupt Disable Register
Name: TC_IDRx [x=0..2]
Address: 0x40080028 (0)[0], 0x40080068 (0)[1], 0x400800A8 (0)[2], 0x40084028 (1)[0], 0x40084068 (1)[1],
0x400840A8 (1)[2], 0x40088028 (2)[0], 0x40088068 (2)[1], 0x400880A8 (2)[2]
Access: Write-only
• COVFS: Counter Overflow
0: No effect.
1: Disables the Counter Overflow Interrupt.
• LOVRS: Load Overrun
0: No effect.
1: Disables the Load Overrun Interrupt (if TC_CMRx.WAVE = 0).
• CPAS: RA Compare
0: No effect.
1: Disables the RA Compare Interrupt (if TC_CMRx.WAVE = 1).
• CPBS: RB Compare
0: No effect.
1: Disables the RB Compare Interrupt (if TC_CMRx.WAVE = 1).
• CPCS: RC Compare
0: No effect.
1: Disables the RC Compare Interrupt.
• LDRAS: RA Loading
0: No effect.
1: Disables the RA Load Interrupt (if TC_CMRx.WAVE = 0).
• LDRBS: RB Loading
0: No effect.
1: Disables the RB Load Interrupt (if TC_CMRx.WAVE = 0).
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS
AtmeL
897
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• ETRGS: External Trigger
0: No effect.
1: Disables the External Trigger Interrupt.
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
898
36.7.12 TC Interrupt Mask Register
Name: TC_IMRx [x=0..2]
Address: 0x4008002C (0)[0], 0x4008006C (0)[1], 0x400800AC (0)[2], 0x4008402C (1)[0], 0x4008406C (1)[1],
0x400840AC (1)[2], 0x4008802C (2)[0], 0x4008806C (2)[1], 0x400880AC (2)[2]
Access: Read-only
• COVFS: Counter Overflow
0: The Counter Overflow Interrupt is disabled.
1: The Counter Overflow Interrupt is enabled.
• LOVRS: Load Overrun
0: The Load Overrun Interrupt is disabled.
1: The Load Overrun Interrupt is enabled.
• CPAS: RA Compare
0: The RA Compare Interrupt is disabled.
1: The RA Compare Interrupt is enabled.
• CPBS: RB Compare
0: The RB Compare Interrupt is disabled.
1: The RB Compare Interrupt is enabled.
• CPCS: RC Compare
0: The RC Compare Interrupt is disabled.
1: The RC Compare Interrupt is enabled.
• LDRAS: RA Loading
0: The Load RA Interrupt is disabled.
1: The Load RA Interrupt is enabled.
• LDRBS: RB Loading
0: The Load RB Interrupt is disabled.
1: The Load RB Interrupt is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS
AtmeL
899
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• ETRGS: External Trigger
0: The External Trigger Interrupt is disabled.
1: The External Trigger Interrupt is enabled.
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
900
36.7.13 TC Block Control Register
Name: TC_BCR
Address: 0x400800C0 (0), 0x400840C0 (1), 0x400880C0 (2)
Access: Write-only
• SYNC: Synchro Command
0: No effect.
1: Asserts the SYNC signal which generates a software trigger simultaneously for each of the channels.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––SYNC
AtmeL
901
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
36.7.14 TC Block Mode Register
Name: TC_BMR
Address: 0x400800C4 (0), 0x400840C4 (1), 0x400880C4 (2)
Access: Read/Write
This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.
• TC0XC0S: External Clock Signal 0 Selection
• TC1XC1S: External Clock Signal 1 Selection
• TC2XC2S: External Clock Signal 2 Selection
• QDEN: Quadrature Decoder Enabled
0: Disabled.
1: Enables the QDEC (filter, edge detection and quadrature decoding).
Quadrature decoding (direction change) can be disabled using QDTRANS bit.
One of the POSEN or SPEEDEN bits must be also enabled.
31 30 29 28 27 26 25 24
–––––– MAXFILT
23 22 21 20 19 18 17 16
MAXFILT – – IDXPHB SWAP
15 14 13 12 11 10 9 8
INVIDX INVB INVA EDGPHA QDTRANS SPEEDEN POSEN QDEN
76543210
– – TC2XC2S TC1XC1S TC0XC0S
Value Name Description
0 TCLK0 Signal connected to XC0: TCLK0
1– Reserved
2 TIOA1 Signal connected to XC0: TIOA1
3 TIOA2 Signal connected to XC0: TIOA2
Value Name Description
0 TCLK1 Signal connected to XC1: TCLK1
1– Reserved
2 TIOA0 Signal connected to XC1: TIOA0
3 TIOA2 Signal connected to XC1: TIOA2
Value Name Description
0 TCLK2 Signal connected to XC2: TCLK2
1– Reserved
2 TIOA0 Signal connected to XC2: TIOA0
3 TIOA1 Signal connected to XC2: TIOA1
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
902
• POSEN: Position Enabled
0: Disable position.
1: Enables the position measure on channel 0 and 1.
• SPEEDEN: Speed Enabled
0: Disabled.
1: Enables the speed measure on channel 0, the time base being provided by channel 2.
• QDTRANS: Quadrature Decoding Transparent
0: Full quadrature decoding logic is active (direction change detected).
1: Quadrature decoding logic is inactive (direction change inactive) but input filtering and edge detection are performed.
• EDGPHA: Edge on PHA Count Mode
0: Edges are detected on PHA only.
1: Edges are detected on both PHA and PHB.
• INVA: Inverted PHA
0: PHA (TIOA0) is directly driving the QDEC.
1: PHA is inverted before driving the QDEC.
• INVB: Inverted PHB
0: PHB (TIOB0) is directly driving the QDEC.
1: PHB is inverted before driving the QDEC.
• INVIDX: Inverted Index
0: IDX (TIOA1) is directly driving the QDEC.
1: IDX is inverted before driving the QDEC.
• SWAP: Swap PHA and PHB
0: No swap between PHA and PHB.
1: Swap PHA and PHB internally, prior to driving the QDEC.
• IDXPHB: Index Pin is PHB Pin
0: IDX pin of the rotary sensor must drive TIOA1.
1: IDX pin of the rotary sensor must drive TIOB0.
• MAXFILT: Maximum Filter
1–63: Defines the filtering capabilities.
Pulses with a period shorter than MAXFILT+1 peripheral clock cycles are discarded.
AtmeL
903
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
36.7.15 TC QDEC Interrupt Enable Register
Name: TC_QIER
Address: 0x400800C8 (0), 0x400840C8 (1), 0x400880C8 (2)
Access: Write-only
• IDX: Index
0: No effect.
1: Enables the interrupt when a rising edge occurs on IDX input.
• DIRCHG: Direction Change
0: No effect.
1: Enables the interrupt when a change on rotation direction is detected.
• QERR: Quadrature Error
0: No effect.
1: Enables the interrupt when a quadrature error occurs on PHA, PHB.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––QERRDIRCHGIDX
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
904
36.7.16 TC QDEC Interrupt Disable Register
Name: TC_QIDR
Address: 0x400800CC (0), 0x400840CC (1), 0x400880CC (2)
Access: Write-only
• IDX: Index
0: No effect.
1: Disables the interrupt when a rising edge occurs on IDX input.
• DIRCHG: Direction Change
0: No effect.
1: Disables the interrupt when a change on rotation direction is detected.
• QERR: Quadrature Error
0: No effect.
1: Disables the interrupt when a quadrature error occurs on PHA, PHB.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––QERRDIRCHGIDX
AtmeL
905
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
36.7.17 TC QDEC Interrupt Mask Register
Name: TC_QIMR
Address: 0x400800D0 (0), 0x400840D0 (1), 0x400880D0 (2)
Access: Read-only
• IDX: Index
0: The interrupt on IDX input is disabled.
1: The interrupt on IDX input is enabled.
• DIRCHG: Direction Change
0: The interrupt on rotation direction change is disabled.
1: The interrupt on rotation direction change is enabled.
• QERR: Quadrature Error
0: The interrupt on quadrature error is disabled.
1: The interrupt on quadrature error is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––QERRDIRCHGIDX
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
906
36.7.18 TC QDEC Interrupt Status Register
Name: TC_QISR
Address: 0x400800D4 (0), 0x400840D4 (1), 0x400880D4 (2)
Access: Read-only
• IDX: Index
0: No Index input change since the last read of TC_QISR.
1: The IDX input has changed since the last read of TC_QISR.
• DIRCHG: Direction Change
0: No change on rotation direction since the last read of TC_QISR.
1: The rotation direction changed since the last read of TC_QISR.
• QERR: Quadrature Error
0: No quadrature error since the last read of TC_QISR.
1: A quadrature error occurred since the last read of TC_QISR.
•DIR: Direction
Returns an image of the actual rotation direction.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––––DIR
76543210
–––––QERRDIRCHGIDX
AtmeL
907
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
36.7.19 TC Fault Mode Register
Name: TC_FMR
Address: 0x400800D8 (0), 0x400840D8 (1), 0x400880D8 (2)
Access: Read/Write
This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.
• ENCF0: Enable Compare Fault Channel 0
0: Disables the FAULT output source (CPCS flag) from channel 0.
1: Enables the FAULT output source (CPCS flag) from channel 0.
• ENCF1: Enable Compare Fault Channel 1
0: Disables the FAULT output source (CPCS flag) from channel 1.
1: Enables the FAULT output source (CPCS flag) from channel 1.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––ENCF1ENCF0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
908
36.7.20 TC Write Protection Mode Register
Name: TC_WPMR
Address: 0x400800E4 (0), 0x400840E4 (1), 0x400880E4 (2)
Access: Read/Write
• WPEN: Write Protection Enable
0: Disables the write protection if WPKEY corresponds to 0x54494D (“TIM” in ASCII).
1: Enables the write protection if WPKEY corresponds to 0x54494D (“TIM” in ASCII).
The Timer Counter clock of the first channel must be enabled to access this register.
See Section 36.6.17 ”Register Write Protection”, for a list of registers that can be write-protected and Timer Counter clock
conditions.
• WPKEY: Write Protection Key
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
–––––––WPEN
Value Name Description
0x54494D PASSWD Writing any other value in this field aborts the write operation of the WPEN bit.
Always reads as 0.
AtmeL
909
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
37. High Speed MultiMedia Card Interface (HSMCI)
37.1 Description
The High Speed Multimedia Card Interface (HSMCI) supports the MultiMedia Card (MMC) Specification V4.3, the
SD Memory Card Specification V2.0, the SDIO V2.0 specification and CE-ATA V1.1.
The HSMCI includes a command register, response registers, data registers, timeout counters and error detection
logic that automatically handle the transmission of commands and, when required, the reception of the associated
responses and data with a limited processor overhead.
The HSMCI supports stream, block and multi block data read and write, and is compatible with the DMA Controller
(DMAC), minimizing processor intervention for large buffer transfers.
The HSMCI operates at a rate of up to Master Clock divided by 2 and supports the interfacing of 2 slot(s). Each
slot may be used to interface with a High Speed MultiMediaCard bus (up to 30 Cards) or with an SD Memory Card.
Only one slot can be selected at a time (slots are multiplexed). A bit field in the SD Card Register performs this
selection.
The SD Memory Card communication is based on a 9-pin interface (clock, command, four data and three power
lines) and the High Speed MultiMedia Card on a 7-pin interface (clock, command, one data, three power lines and
one reserved for future use).
The SD Memory Card interface also supports High Speed MultiMedia Card operations. The main differences
between SD and High Speed MultiMedia Cards are the initialization process and the bus topology.
HSMCI fully supports CE-ATA Revision 1.1, built on the MMC System Specification v4.0. The module includes
dedicated hardware to issue the command completion signal and capture the host command completion signal
disable.
37.2 Embedded Characteristics
Compatible with MultiMedia Card Specification Version 4.3
Compatible with SD Memory Card Specification Version 2.0
Compatible with SDIO Specification Version 2.0
Compatible with CE-ATA Specification 1.1
Cards Clock Rate Up to Master Clock Divided by 2
Boot Operation Mode Support
High Speed Mode Support
Embedded Power Management to Slow Down Clock Rate When Not Used
Supports 2 Multiplexed Slot(s)
̶Each Slot for either a High Speed MultiMediaCard Bus (Up to 30 Cards) or an SD Memory Card
Support for Stream, Block and Multi-block Data Read and Write
Supports Connection to DMA Controller (DMAC)
̶Minimizes Processor Intervention for Large Buffer Transfers
Built in FIFO (from 16 to 256 bytes) with Large Memory Aperture Supporting Incremental Access
Support for CE-ATA Completion Signal Disable Command
Protection Against Unexpected Modification On-the-Fly of the Configuration Registers
_.|.__.|.__.|.__H__.|.__.I._ DDDDDDDDD
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
910
37.3 Block Diagram
Figure 37-1. Block Diagram
Note: 1. When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to HSMCIx_CDA,
MCCDB to HSMCIx_CDB, MCDAy to HSMCIx_DAy, MCDBy to HSMCIx_DBy.
HSMCI Interface
Interrupt Control
PIO
APB Bridge
PMC MCK
HSMCI Interrupt
MCCK(1)
MCCDA(1)
MCDA0(1)
MCDA1(1)
MCDA2(1)
MCDA3(1)
MCCDB(1)
MCDB0(1)
MCDB1(1)
MCDB2(1)
MCDB3(1)
APB
MCDB4(1)
MCDB5(1)
MCDB6(1)
MCDB7(1)
DMAC
An ex File Sys AtmeL
911
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
37.4 Application Block Diagram
Figure 37-2. Application Block Diagram
37.5 Pin Name List
Notes: 1. I: Input, O: Output, PP: Push/Pull, OD: Open Drain.
2. When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to HSMCIx_CDA,
MCCDB to HSMCIx_CDB, MCCDC to HSMCIx_CDC, MCCDD to HSMCIx_CDD, MCDAy to HSMCIx_DAy, MCDBy to
HSMCIx_DBy, MCDCy to HSMCIx_DCy, MCDDy to HSMCIx_DDy.
,.
2345617
MMC
23456178
SDCard
9
Physical Layer
HSMCI Interface
Application Layer
ex: File System, Audio, Security, etc.
9 1011 12138
Table 37-1. I/O Lines Description for 8-bit Configuration
Pin Name(2) Pin Description Type(1) Comments
MCCDA/MCCDB Command/response I/O/PP/OD CMD of an MMC or SDCard/SDIO
MCCK Clock I/O CLK of an MMC or SD Card/SDIO
MCDA0 - MCDA7 Data 0..7 of Slot A I/O/PP DAT[0..7] of an MMC
DAT[0..3] of an SD Card/SDIO
MCDB0 - MCDB7 Data 0..7 of Slot B I/O/PP DAT[0..7] of an MMC
DAT[0..3] of an SD Card/SDIO
MCDC0 - MCDC7 Data 0..7 of Slot C I/O/PP DAT[0..7] of an MMC
DAT[0..3] of an SD Card/SDIO
MCDD0 - MCDD7 Data 0..7 of Slot D I/O/PP DAT[0..7] of an MMC
DAT[0..3] of an SD Card/SDIO
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
912
37.6 Product Dependencies
37.6.1 I/O Lines
The pins used for interfacing the High Speed MultiMedia Cards or SD Cards are multiplexed with PIO lines. The
programmer must first program the PIO controllers to assign the peripheral functions to HSMCI pins.
37.6.2 Power Management
The HSMCI is clocked through the Power Management Controller (PMC), so the programmer must first configure
the PMC to enable the HSMCI clock.
37.6.3 Interrupt
The HSMCI interface has an interrupt line connected to the Nested Vector Interrupt Controller (NVIC).
Handling the HSMCI interrupt requires programming the NVIC before configuring the HSMCI.
Table 37-2. I/O Lines
Instance Signal I/O Line Peripheral
HSMCI MCCDA PA20 A
HSMCI MCCDB PE20 B
HSMCI MCCK PA19 A
HSMCI MCDA0 PA21 A
HSMCI MCDA1 PA22 A
HSMCI MCDA2 PA23 A
HSMCI MCDA3 PA24 A
HSMCI MCDA4 PD0 B
HSMCI MCDA5 PD1 B
HSMCI MCDA6 PD2 B
HSMCI MCDA7 PD3 B
HSMCI MCDB0 PE22 B
HSMCI MCDB1 PE24 B
HSMCI MCDB2 PE26 B
HSMCI MCDB3 PE27 B
Table 37-3. Peripheral IDs
Instance ID
HSMCI 21
AtmeL
913
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
37.7 Bus Topology
Figure 37-3. High Speed MultiMedia Memory Card Bus Topology
The High Speed MultiMedia Card communication is based on a 13-pin serial bus interface. It has three
communication lines and four supply lines.
Notes: 1. I: Input, O: Output, PP: Push/Pull, OD: Open Drain.
2. When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to
HSMCIx_CDA, MCCDB to HSMCIx_CDB, MCDAy to HSMCIx_DAy, MCDBy to HSMCIx_DBy.
Table 37-4. Bus Topology
Pin
Number Name Type(1) Description
HSMCI Pin
Name((2)
(Slot z)
1 DAT[3] I/O/PP Data MCDz3
2 CMD I/O/PP/OD Command/response MCCDz
3 VSS1 S Supply voltage ground VSS
4 VDD S Supply voltage VDD
5 CLK I/O Clock MCCK
6 VSS2 S Supply voltage ground VSS
7 DAT[0] I/O/PP Data 0 MCDz0
8 DAT[1] I/O/PP Data 1 MCDz1
9 DAT[2] I/O/PP Data 2 MCDz2
10 DAT[4] I/O/PP Data 4 MCDz4
11 DAT[5] I/O/PP Data 5 MCDz5
12 DAT[6] I/O/PP Data 6 MCDz6
13 DAT[7] I/O/PP Data 7 MCDz7
2345617
MMC
91011 12138
I I I IIIIIII IIIIIII IIIIIII III III III III III III AtmeL
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Figure 37-4. MMC Bus Connections (One Slot)
Note: When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to HSMCIx_CDA
MCDAy to HSMCIx_DAy.
Figure 37-5. SD Memory Card Bus Topology
The SD Memory Card bus includes the signals listed in Table 37-5.
Notes: 1. I: input, O: output, PP: Push Pull, OD: Open Drain.
2. When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to
HSMCIx_CDA, MCCDB to HSMCIx_CDB, MCDAy to HSMCIx_DAy, MCDBy to HSMCIx_DBy.
Table 37-5. SD Memory Card Bus Signals
Pin
Number Name Type(1) Description
HSMCI Pin
Name(2)
(Slot z)
1 CD/DAT[3] I/O/PP Card detect/ Data line Bit 3 MCDz3
2 CMD PP Command/response MCCDz
3 VSS1 S Supply voltage ground VSS
4 VDD S Supply voltage VDD
5 CLK I/O Clock MCCK
6 VSS2 S Supply voltage ground VSS
7 DAT[0] I/O/PP Data line Bit 0 MCDz0
8 DAT[1] I/O/PP Data line Bit 1 or Interrupt MCDz1
9 DAT[2] I/O/PP Data line Bit 2 MCDz2
MCCDA
MCDA0
MCCK
HSMCI
2345617
MMC1
9 1011 12138
2345617
MMC2
9 1011 12138
2345617
MMC3
9 1011 12138
23456178
SD CARD
9
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Figure 37-6. SD Card Bus Connections with One Slot
Note: When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to HSMCIx_CDA
MCDAy to HSMCIx_DAy.
Figure 37-7. SD Card Bus Connections with Two Slots
Note: When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK,MCCDA to HSMCIx_CDA,
MCDAy to HSMCIx_DAy, MCCDB to HSMCIx_CDB, MCDBy to HSMCIx_DBy.
Figure 37-8. Mixing High Speed MultiMedia and SD Memory Cards with Two Slots
Note: When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to
HSMCIx_CDA, MCDAy to HSMCIx_DAy, MCCDB to HSMCIx_CDB, MCDBy to HSMCIx_DBy.
2345617
MCDA0 - MCDA3
MCCDA
MCCK
8
SD CARD
9
2345617
MCDA0 - MCDA3
MCCDA
MCCK
8
SD CARD 1
9
23456178
SD CARD 2
9
MCDB0 - MCDB3
MCCDB
MCDA0 - MCDA7
MCCK
MCCDA
23456178
SD CARD
9
MCDB0 - MCDB3
MCCDB
2345617
MMC1
9 1011 12138
2345617
MMC2
9 1011 12138
2345617
MMC3
9 1011 12138
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When the HSMCI is configured to operate with SD memory cards, the width of the data bus can be selected in the
HSMCI_SDCR register. Clearing the SDCBUS bit in this register means that the width is one bit; setting it means
that the width is four bits. In the case of High Speed MultiMedia cards, only the data line 0 is used. The other data
lines can be used as independent PIOs.
37.8 High Speed MultiMediaCard Operations
After a power-on reset, the cards are initialized by a special message-based High Speed MultiMediaCard bus
protocol. Each message is represented by one of the following tokens:
Command: A command is a token that starts an operation. A command is sent from the host either to a
single card (addressed command) or to all connected cards (broadcast command). A command is
transferred serially on the CMD line.
Response: A response is a token which is sent from an addressed card or (synchronously) from all
connected cards to the host as an answer to a previously received command. A response is transferred
serially on the CMD line.
Data: Data can be transferred from the card to the host or vice versa. Data is transferred via the data line.
Card addressing is implemented using a session address assigned during the initialization phase by the bus
controller to all currently connected cards. Their unique CID number identifies individual cards.
The structure of commands, responses and data blocks is described in the High Speed MultiMedia-Card System
Specification. See also Table 37-6 on page 917.
High Speed MultiMediaCard bus data transfers are composed of these tokens.
There are different types of operations. Addressed operations always contain a command and a response token.
In addition, some operations have a data token; the others transfer their information directly within the command or
response structure. In this case, no data token is present in an operation. The bits on the DAT and the CMD lines
are transferred synchronous to the clock HSMCI Clock.
Two types of data transfer commands are defined:
Sequential commands: These commands initiate a continuous data stream. They are terminated only when
a stop command follows on the CMD line. This mode reduces the command overhead to an absolute
minimum.
Block-oriented commands: These commands send a data block succeeded by CRC bits.
Both read and write operations allow either single or multiple block transmission. A multiple block transmission is
terminated when a stop command follows on the CMD line similarly to the sequential read or when a multiple block
transmission has a pre-defined block count (See “Data Transfer Operation” on page 919.).
The HSMCI provides a set of registers to perform the entire range of High Speed MultiMedia Card operations.
37.8.1 Command - Response Operation
After reset, the HSMCI is disabled and becomes valid after setting the MCIEN bit in the HSMCI_CR Control
Register.
The PWSEN bit saves power by dividing the HSMCI clock by 2PWSDIV + 1 when the bus is inactive.
The two bits, RDPROOF and WRPROOF in the HSMCI Mode Register (HSMCI_MR) allow stopping the HSMCI
Clock during read or write access if the internal FIFO is full. This will guarantee data integrity, not bandwidth.
All the timings for High Speed MultiMedia Card are defined in the High Speed MultiMediaCard System
Specification.
The two bus modes (open drain and push/pull) needed to process all the operations are defined in the HSMCI
command register. The HSMCI_CMDR allows a command to be carried out.
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For example, to perform an ALL_SEND_CID command:
The command ALL_SEND_CID and the fields and values for the HSMCI_CMDR Control Register are described in
Table 37-6 and Table 37-7.
Note: bcr means broadcast command with response.
The HSMCI_ARGR contains the argument field of the command.
To send a command, the user must perform the following steps:
Fill the argument register (HSMCI_ARGR) with the command argument.
Set the command register (HSMCI_CMDR) (see Table 37-7).
The command is sent immediately after writing the command register.
While the card maintains a busy indication (at the end of a STOP_TRANSMISSION command CMD12, for
example), a new command shall not be sent. The NOTBUSY flag in the status register (HSMCI_SR) is asserted
when the card releases the busy indication.
If the command requires a response, it can be read in the HSMCI response register (HSMCI_RSPR). The
response size can be from 48 bits up to 136 bits depending on the command. The HSMCI embeds an error
detection to prevent any corrupted data during the transfer.
The following flowchart shows how to send a command to the card and read the response if needed. In this
example, the status register bits are polled but setting the appropriate bits in the interrupt enable register
(HSMCI_IER) allows using an interrupt method.
Host Command NID Cycles CID
CMD S T Content CRC E Z ****** Z S T Content Z Z Z
Table 37-6. ALL_SEND_CID Command Description
CMD Index Type Argument Resp Abbreviation Command
Description
CMD2 bcr [31:0] stuff bits R2 ALL_SEND_CID Asks all cards to send
their CID numbers on
the CMD line
Table 37-7. Fields and Values for HSMCI_CMDR Command Register
Field Value
CMDNB (command number) 2 (CMD2)
RSPTYP (response type) 2 (R2: 136 bits response)
SPCMD (special command) 0 (not a special command)
OPCMD (open drain command) 1
MAXLAT (max latency for command to response) 0 (NID cycles ==> 5 cycles)
TRCMD (transfer command) 0 (No transfer)
TRDIR (transfer direction) X (available only in transfer command)
TRTYP (transfer type) X (available only in transfer command)
IOSPCMD (SDIO special command) 0 (not a special command)
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Table 37-8. Command/Response Functional Flow Diagram
Note: 1. If the command is SEND_OP_COND, the CRC error flag is always present (refer to R3 response in the High
Speed MultiMedia Card specification).
RETURN OK
RETURN ERROR(1)
RETURN OK
Set the command argument
HSMCI_ARGR = Argument
(1)
Set the command
HSMCI_CMDR = Command
Read HSMCI_SR
CMDRDY
Status error flags?
Read response if required
Yes
Wait for command
ready status flag
Check error bits in the
status register
(1)
0
1
Does the command involve
a busy indication?
No
Read HSMCI_SR
0
NOTBUSY
1
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37.8.2 Data Transfer Operation
The High Speed MultiMedia Card allows several read/write operations (single block, multiple blocks, stream, etc.).
These kinds of transfer can be selected setting the Transfer Type (TRTYP) field in the HSMCI Command Register
(HSMCI_CMDR).
These operations can be done using the features of the DMA Controller.
In all cases, the block length (BLKLEN field) must be defined either in the mode register HSMCI_MR, or in the
Block Register HSMCI_BLKR. This field determines the size of the data block.
Consequent to MMC Specification 3.1, two types of multiple block read (or write) transactions are defined (the host
can use either one at any time):
Open-ended/Infinite Multiple block read (or write):
The number of blocks for the read (or write) multiple block operation is not defined. The card will
continuously transfer (or program) data blocks until a stop transmission command is received.
Multiple block read (or write) with pre-defined block count (since version 3.1 and higher):
The card will transfer (or program) the requested number of data blocks and terminate the transaction. The
stop command is not required at the end of this type of multiple block read (or write), unless terminated with
an error. In order to start a multiple block read (or write) with pre-defined block count, the host must correctly
program the HSMCI Block Register (HSMCI_BLKR). Otherwise the card will start an open-ended multiple
block read. The BCNT field of the Block Register defines the number of blocks to transfer (from 1 to 65535
blocks). Programming the value 0 in the BCNT field corresponds to an infinite block transfer.
37.8.3 Read Operation
The following flowchart (Figure 37-9) shows how to read a single block with or without use of DMAC facilities. In
this example, a polling method is used to wait for the end of read. Similarly, the user can configure the interrupt
enable register (HSMCI_IER) to trigger an interrupt at the end of read.
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Figure 37-9. Read Functional Flow Diagram
Notes: 1. It is assumed that this command has been correctly sent (see Figure 37-8).
2. This field is also accessible in the HSMCI Block Register (HSMCI_BLKR).
Read status register HSMCI_SR
Send SELECT/DESELECT_CARD
command(1) to select the card
Send SET_BLOCKLEN command(1)
Read with DMAC
Number of words to read = 0 ?
Poll the bit
RXRDY = 0?
Read data = HSMCI_RDR
Number of words to read =
Number of words to read -1
Send READ_SINGLE_BLOCK
command(1)
Yes
Set the DMAEN bit
HSMCI_DMA |= DMAEN
Set the block length (in bytes)
HSMCI_BLKR |= (BlockLength << 16)(2)
Configure the DMA channel X
DMAC_SADDRx = Data Address
DMAC_BTSIZE = BlockLength/4
DMACHEN[X] = TRUE
Send READ_SINGLE_BLOCK
command(1)
Read status register HSMCI_SR
Poll the bit
XFRDONE = 0? Ye s
RETURN
RETURN
YesNo
No
No
Yes
No
Number of words to read = BlockLength/4
Reset the DMAEN bit
HSMCI_DMA &= ~DMAEN
Set the block length (in bytes)
HSMCI_MR l= (BlockLength<<16) (2)
Set the block count (if neccessary)
HSMCI_BLKR l= (BlockCount<<0)
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37.8.4 Write Operation
In write operation, the HSMCI Mode Register (HSMCI_MR) is used to define the padding value when writing non-
multiple block size. If the bit PADV is 0, then 0x00 value is used when padding data, otherwise 0xFF is used.
If set, the bit DMAEN in the HSMCI_DMA register enables DMA transfer.
The following flowchart (Figure 37-10) shows how to write a single block with or without use of DMA facilities.
Polling or interrupt method can be used to wait for the end of write according to the contents of the Interrupt Mask
Register (HSMCI_IMR).
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Figure 37-10. Write Functional Flow Diagram
Note: 1. It is assumed that this command has been correctly sent (see Figure 37-8).
2. This field is also accessible in the HSMCI Block Register (HSMCI_BLKR).
The following flowchart (Figure 37-11) shows how to manage read multiple block and write multiple block transfers
with the DMA Controller. Polling or interrupt method can be used to wait for the end of write according to the
contents of the Interrupt Mask Register (HSMCI_IMR).
Send SELECT/DESELECT_CARD
command(1) to select the card
Send SET_BLOCKLEN command(1)
Write using DMAC
Send WRITE_SINGLE_BLOCK
command(1)
Configure the DMA channel X
DMAC_DADDRx = Data Address to write
DMAC_BTSIZE = BlockLength/4
Send WRITE_SINGLE_BLOCK
command(1)
Read status register HSMCI_SR
Poll the bit
XFRDONE = 0?
Yes
No Yes
No
Read status register HSMCI_SR
Number of words to write = 0 ?
Poll the bit
TXRDY = 0?
HSMCI_TDR = Data to write
Number of words to write =
Number of words to write -1
Yes
RETURN
No
Yes
No
Number of words to write = BlockLength/4
DMAC_CHEN[X] = TRUE
Reset theDMAEN bit
HSMCI_DMA &= ~DMAEN
Set the block length (in bytes)
HSMCI_MR |= (BlockLength) <<16)(2)
Set the block count (if necessary)
HSMCI_BLKR |= (BlockCount << 0)
Set the DMAEN bit
HSMCI_DMA |= DMAEN
Set the block length (in bytes)
HSMCI_BLKR |= (BlockLength << 16)(2)
RETURN
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Figure 37-11. Read Multiple Block and Write Multiple Block
Notes: 1. It is assumed that this command has been correctly sent (see Figure 37-8).
2. Handle errors reported in HSMCI_SR.
Send SELECT/DESELECT_CARD
command(1) to select the card
Send SET_BLOCKLEN command(1)
Set the block length
HSMCI_MR |= (BlockLength << 16)
Set the DMAEN bit
HSMCI_DMA |= DMAEN
Configure the HDMA channel X
DMAC_SADDRx and DMAC_DADDRx
DMAC_BTSIZE = BlockLength/4
Send WRITE_MULTIPLE_BLOCK or
READ_MULTIPLE_BLOCK command(1)
Read status register DMAC_EBCISR
and Poll Bit CBTC[X]
New Buffer ?(2)
No
DMAC_CHEN[X] = TRUE
Poll the bit
XFRDONE = 1 No
RETURN
Yes
Send STOP_TRANSMISSION
command(1)
Yes
Read status register HSMCI_SR
and Poll Bit FIFOEMPTY
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37.8.5 WRITE_SINGLE_BLOCK Operation using DMA Controller
1. Wait until the current command execution has successfully terminated.
c. Check that CMDRDY and NOTBUSY fields are asserted in HSMCI_SR
2. Program the block length in the card. This value defines the value block_length.
3. Program the block length in the HSMCI configuration register with block_length value.
4. Program HSMCI_DMA register with the following fields:
̶OFFSET field with dma_offset.
̶CHKSIZE is user defined and set according to DMAC_DCSIZE.
̶DMAEN is set to true to enable DMA hardware handshaking in the HSMCI. This bit was previously set
to false.
5. Issue a WRITE_SINGLE_BLOCK command writing HSMCI_ARG then HSMCI_CMDR.
6. Program the DMA Controller.
a.Read the channel Register to choose an available (disabled) channel.
b.Clear any pending interrupts on the channel from the previous DMAC transfer by reading the
DMAC_EBCISR register.
c. Program the channel registers.
d. The DMAC_SADDRx register for channel x must be set to the location of the source data. When the
first data location is not word aligned, the two LSB bits define the temporary value called dma_offset.
The two LSB bits of DMAC_SADDRx must be set to 0.
e. The DMAC_DADDRx register for channel x must be set with the starting address of the HSMCI_FIFO
address.
f. Program DMAC_CTRLAx register of channel x with the following field’s values:
–DST_WIDTH is set to WORD.
–SRC_WIDTH is set to WORD.
–DCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.
–BTSIZE is programmed with CEILING((block_length + dma_offset) / 4), where the ceiling function
is the function that returns the smallest integer not less than x.
g. Program DMAC_CTRLBx register for channel x with the following field’s values:
–DST_INCR is set to INCR, the block_length value must not be larger than the HSMCI_FIFO
aperture.
–SRC_INCR is set to INCR.
–FC field is programmed with memory to peripheral flow control mode.
–both DST_DSCR and SRC_DSCR are set to 1 (descriptor fetch is disabled).
–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, the DMA controller is
able to prefetch data and write HSMCI simultaneously.
h. Program DMAC_CFGx register for channel x with the following field’s values:
–FIFOCFG defines the watermark of the DMAC channel FIFO.
–DST_H2SEL is set to true to enable hardware handshaking on the destination.
–DST_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host
Controller.
i. Enable Channel x, writing one to DMAC_CHER[x]. The DMAC is ready and waiting for request.
7. Wait for XFRDONE in HSMCI_SR register.
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37.8.6 READ_SINGLE_BLOCK Operation using DMA Controller
37.8.6.1 Block Length is Multiple of 4
1. Wait until the current command execution has successfully completed.
a.Check that CMDRDY and NOTBUSY are asserted in HSMCI_SR.
2. Program the block length in the card. This value defines the value block_length.
3. Program the block length in the HSMCI configuration register with block_length value.
4. Set RDPROOF bit in HSMCI_MR to avoid overflow.
5. Program HSMCI_DMA register with the following fields:
̶ROPT field is set to 0.
̶OFFSET field is set to 0.
̶CHKSIZE is user defined.
̶DMAEN is set to true to enable DMAC hardware handshaking in the HSMCI. This bit was previously
set to false.
6. Issue a READ_SINGLE_BLOCK command.
7. Program the DMA controller.
a.Read the channel Register to choose an available (disabled) channel.
b.Clear any pending interrupts on the channel from the previous DMA transfer by reading the
DMAC_EBCISR register.
c. Program the channel registers.
d. The DMAC_SADDRx register for channel x must be set with the starting address of the HSMCI_FIFO
address.
e. The DMAC_DADDRx register for channel x must be word aligned.
f. Program DMAC_CTRLAx register of channel x with the following field’s values:
–DST_WIDTH is set to WORD.
–SRC_WIDTH is set to WORD.
–SCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.
–BTSIZE is programmed with block_length/4.
g. Program DMAC_CTRLBx register for channel x with the following field’s values:
̶DST_INCR is set to INCR.
̶SRC_INCR is set to INCR.
̶FC field is programmed with peripheral to memory flow control mode.
̶both DST_DSCR and SRC_DSCR are set to 1 (descriptor fetch is disabled).
̶DIF and SIF are set with their respective layer ID. If SIF is different from DIF, the DMA controller is
able to prefetch data and write HSMCI simultaneously.
h. Program DMAC_CFGx register for channel x with the following field’s values:
–FIFOCFG defines the watermark of the DMA channel FIFO.
–SRC_H2SEL is set to true to enable hardware handshaking on the destination.
–SRC_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host
Controller.
–Enable Channel x, writing one to DMAC_CHER[x]. The DMAC is ready and waiting for request.
8. Wait for XFRDONE in HSMCI_SR register.
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37.8.6.2 Block Length is Not Multiple of 4 and Padding Not Used (ROPT field in HSMCI_DMA register set to 0)
In the previous DMA transfer flow (block length multiple of 4), the DMA controller is configured to use only WORD
AHB access. When the block length is no longer a multiple of 4 this is no longer true. The DMA controller is
programmed to copy exactly the block length number of bytes using 2 transfer descriptors.
1. Use the previous step until READ_SINGLE_BLOCK then
2. Program the DMA controller to use a two descriptors linked list.
a.Read the channel Register to choose an available (disabled) channel.
b.Clear any pending interrupts on the channel from the previous DMA transfer by reading the
DMAC_EBCISR register.
c. Program the channel registers in the Memory for the first descriptor. This descriptor will be word ori-
ented. This descriptor is referred to as LLI_W, standing for LLI word oriented transfer.
d. The LLI_W.DMAC_SADDRx field in memory must be set with the starting address of the
HSMCI_FIFO address.
e. The LLI_W.DMAC_DADDRx field in the memory must be word aligned.
f. Program LLI_W.DMAC_CTRLAx with the following field’s values:
–DST_WIDTH is set to WORD.
–SRC_WIDTH is set to WORD.
–SCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.
–BTSIZE is programmed with block_length/4. If BTSIZE is zero, this descriptor is skipped later.
g. Program LLI_W.DMAC_CTRLBx with the following field’s values:
–DST_INCR is set to INCR
–SRC_INCR is set to INCR
–FC field is programmed with peripheral to memory flow control mode.
–SRC_DSCR is set to zero. (descriptor fetch is enabled for the SRC)
–DST_DSCR is set to one. (descriptor fetch is disabled for the DST)
–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, DMA controller is able
to prefetch data and write HSMCI simultaneously.
h. Program LLI_W.DMAC_CFGx register for channel x with the following field’s values:
–FIFOCFG defines the watermark of the DMA channel FIFO.
–DST_REP is set to zero meaning that address are contiguous.
–SRC_H2SEL is set to true to enable hardware handshaking on the destination.
–SRC_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host
Controller.
i. Program LLI_W.DMAC_DSCRx with the address of LLI_B descriptor. And set DSCRx_IF to the AHB
Layer ID. This operation actually links the Word oriented descriptor on the second byte oriented
descriptor. When block_length[1:0] is equal to 0 (multiple of 4) LLI_W.DMAC_DSCRx points to 0, only
LLI_W is relevant.
j. Program the channel registers in the Memory for the second descriptor. This descriptor will be byte
oriented. This descriptor is referred to as LLI_B, standing for LLI Byte oriented.
k. The LLI_B.DMAC_SADDRx field in memory must be set with the starting address of the
HSMCI_FIFO address.
l. The LLI_B.DMAC_DADDRx is not relevant if previous word aligned descriptor was enabled. If 1, 2 or
3 bytes are transferred that address is user defined and not word aligned.
m. Program LLI_B.DMAC_CTRLAx with the following field’s values:
–DST_WIDTH is set to BYTE.
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–SRC_WIDTH is set to BYTE.
–SCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.
–BTSIZE is programmed with block_length[1:0]. (last 1, 2, or 3 bytes of the buffer).
n. Program LLI_B.DMAC_CTRLBx with the following field’s values:
–DST_INCR is set to INCR
–SRC_INCR is set to INCR
–FC field is programmed with peripheral to memory flow control mode.
–Both SRC_DSCR and DST_DSCR are set to 1 (descriptor fetch is disabled) or Next descriptor
location points to 0.
–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, DMA Controller is able
to prefetch data and write HSMCI simultaneously.
o. Program LLI_B.DMAC_CFGx memory location for channel x with the following field’s values:
̶FIFOCFG defines the watermark of the DMA channel FIFO.
̶SRC_H2SEL is set to true to enable hardware handshaking on the destination.
̶SRC_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host Controller.
p. Program LLI_B.DMAC_DSCR with 0.
q. Program DMAC_CTRLBx register for channel x with 0. its content is updated with the LLI fetch
operation.
r. Program DMAC_DSCRx with the address of LLI_W if block_length greater than 4 else with address
of LLI_B.
s.Enable Channel x writing one to DMAC_CHER[x]. The DMAC is ready and waiting for request.
3. Wait for XFRDONE in HSMCI_SR register.
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37.8.6.3 Block Length is Not Multiple of 4, with Padding Value (ROPT field in HSMCI_DMA register set to 1)
When the ROPT field is set to one, The DMA Controller performs only WORD access on the bus to transfer a non-
multiple of 4 block length. Unlike previous flow, in which the transfer size is rounded to the nearest multiple of 4.
1. Program the HSMCI Interface, see previous flow.
̶ROPT field is set to 1.
2. Program the DMA Controller
a.Read the channel Register to choose an available (disabled) channel.
b.Clear any pending interrupts on the channel from the previous DMA transfer by reading the
DMAC_EBCISR register.
c. Program the channel registers.
d. The DMAC_SADDRx register for channel x must be set with the starting address of the HSMCI_FIFO
address.
e.The DMAC_DADDRx register for channel x must be word aligned.
f. Program DMAC_CTRLAx register of channel x with the following field’s values:
–DST_WIDTH is set to WORD
–SRC_WIDTH is set to WORD
–SCSIZE must be set according to the value of HSMCI_DMA.CHKSIZE Field.
–BTSIZE is programmed with CEILING(block_length/4).
g. Program DMAC_CTRLBx register for channel x with the following field’s values:
–DST_INCR is set to INCR
–SRC_INCR is set to INCR
–FC field is programmed with peripheral to memory flow control mode.
–both DST_DSCR and SRC_DSCR are set to 1. (descriptor fetch is disabled)
–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, the DMA Controller is
able to prefetch data and write HSMCI simultaneously.
h. Program DMAC_CFGx register for channel x with the following field’s values:
–FIFOCFG defines the watermark of the DMA channel FIFO.
–SRC_H2SEL is set to true to enable hardware handshaking on the destination.
–SRC_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host
Controller.
–Enable Channel x writing one to DMAC_CHER[x]. The DMAC is ready and waiting for request.
3. Wait for XFRDONE in HSMCI_SR register.
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37.8.7 WRITE_MULTIPLE_BLOCK
37.8.7.1 One Block per Descriptor
1. Wait until the current command execution has successfully terminated.
a.Check that CMDRDY and NOTBUSY are asserted in HSMCI_SR.
2. Program the block length in the card. This value defines the value block_length.
3. Program the block length in the HSMCI configuration register with block_length value.
4. Program HSMCI_DMA register with the following fields:
̶OFFSET field with dma_offset.
̶CHKSIZE is user defined.
̶DMAEN is set to true to enable DMAC hardware handshaking in the HSMCI. This bit was previously
set to false.
5. Issue a WRITE_MULTIPLE_BLOCK command.
6. Program the DMA Controller to use a list of descriptors. Each descriptor transfers one block of data. Block n
of data is transferred with descriptor LLI(n).
a.Read the channel Register to choose an available (disabled) channel.
b.Clear any pending interrupts on the channel from the previous DMAC transfer by reading the
DMAC_EBCISR register.
c. Program a List of descriptors.
d. The LLI(n).DMAC_SADDRx memory location for channel x must be set to the location of the source
data. When the first data location is not word aligned, the two LSB bits define the temporary value
called dma_offset. The two LSB bits of LLI(n).DMAC_SADDRx must be set to 0.
e. The LLI(n).DMAC_DADDRx register for channel x must be set with the starting address of the
HSMCI_FIFO address.
f. Program LLI(n).DMAC_CTRLAx register of channel x with the following field’s values:
–DST_WIDTH is set to WORD.
–SRC_WIDTH is set to WORD.
–DCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.
–BTSIZE is programmed with CEILING((block_length + dma_offset)/4).
g. Program LLI(n).DMAC_CTRLBx register for channel x with the following field’s values:
–DST_INCR is set to INCR.
–SRC_INCR is set to INCR.
–DST_DSCR is set to 0 (fetch operation is enabled for the destination).
–SRC_DSCR is set to 1 (source address is contiguous).
–FC field is programmed with memory to peripheral flow control mode.
–Both DST_DSCR and SRC_DSCR are set to 1 (descriptor fetch is disabled).
–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, DMA Controller is able
to prefetch data and write HSMCI simultaneously.
h. Program LLI(n).DMAC_CFGx register for channel x with the following field’s values:
–FIFOCFG defines the watermark of the DMA channel FIFO.
–DST_H2SEL is set to true to enable hardware handshaking on the destination.
–SRC_REP is set to 0. (contiguous memory access at block boundary)
–DST_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host
Controller.
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i. If LLI(n) is the last descriptor, then LLI(n).DSCR points to 0 else LLI(n) points to the start address of
LLI(n+1).
j. Program DMAC_CTRLBx for channel register x with 0. Its content is updated with the LLI fetch
operation.
k. Program DMAC_DSCRx for channel register x with the address of the first descriptor LLI(0).
l. Enable Channel x writing one to DMAC_CHER[x]. The DMA is ready and waiting for request.
7. Poll CBTC[x] bit in the DMAC_EBCISR Register.
8. If a new list of buffers shall be transferred, repeat step 6. Check and handle HSMCI errors.
9. Poll FIFOEMPTY field in the HSMCI_SR.
10. Send The STOP_TRANSMISSION command writing HSMCI_ARG then HSMCI_CMDR.
11. Wait for XFRDONE in HSMCI_SR register.
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37.8.8 READ_MULTIPLE_BLOCK
37.8.8.1 Block Length is a Multiple of 4
1. Wait until the current command execution has successfully terminated.
a.Check that CMDRDY and NOTBUSY are asserted in HSMCI_SR.
2. Program the block length in the card. This value defines the value block_length.
3. Program the block length in the HSMCI configuration register with block_length value.
4. Set RDPROOF bit in HSMCI_MR to avoid overflow.
5. Program HSMCI_DMA register with the following fields:
̶ROPT field is set to 0.
̶OFFSET field is set to 0.
̶CHKSIZE is user defined.
̶DMAEN is set to true to enable DMAC hardware handshaking in the HSMCI. This bit was previously
set to false.
6. Issue a READ_MULTIPLE_BLOCK command.
7. Program the DMA Controller to use a list of descriptors:
a.Read the channel Register to choose an available (disabled) channel.
b.Clear any pending interrupts on the channel from the previous DMA transfer by reading the
DMAC_EBCISR register.
c. Program the channel registers in the Memory with the first descriptor. This descriptor will be word ori-
ented. This descriptor is referred to as LLI_W(n), standing for LLI word oriented transfer for block n.
d. The LLI_W(n).DMAC_SADDRx field in memory must be set with the starting address of the
HSMCI_FIFO address.
e. The LLI_W(n).DMAC_DADDRx field in the memory must be word aligned.
f. Program LLI_W(n).DMAC_CTRLAx with the following field’s values:
–DST_WIDTH is set to WORD
–SRC_WIDTH is set to WORD
–SCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.
–BTSIZE is programmed with block_length/4.
g. Program LLI_W(n).DMAC_CTRLBx with the following field’s values:
–DST_INCR is set to INCR.
–SRC_INCR is set to INCR.
–FC field is programmed with peripheral to memory flow control mode.
–SRC_DSCR is set to 0 (descriptor fetch is enabled for the SRC).
–DST_DSCR is set to TRUE (descriptor fetch is disabled for the DST).
–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, the DMA Controller is
able to prefetch data and write HSMCI simultaneously.
h. Program LLI_W(n).DMAC_CFGx register for channel x with the following field’s values:
–FIFOCFG defines the watermark of the DMA channel FIFO.
–DST_REP is set to zero. Addresses are contiguous.
–SRC_H2SEL is set to true to enable hardware handshaking on the destination.
–SRC_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host
Controller.
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i. Program LLI_W(n).DMAC_DSCRx with the address of LLI_W(n+1) descriptor. And set the DSCRx_IF
to the AHB Layer ID. This operation actually links descriptors together. If LLI_W(n) is the last descrip-
tor then LLI_W(n).DMAC_DSCRx points to 0.
j. Program DMAC_CTRLBx register for channel x with 0. its content is updated with the LLI Fetch
operation.
k. Program DMAC_DSCRx register for channel x with the address of LLI_W(0).
l. Enable Channel x writing one to DMAC_CHER[x]. The DMA is ready and waiting for request.
8. Poll CBTC[x] bit in the DMAC_EBCISR Register.
9. If a new list of buffer shall be transferred repeat step 6. Check and handle HSMCI errors.
10. Poll FIFOEMPTY field in the HSMCI_SR.
11. Send The STOP_TRANSMISSION command writing the HSMCI_ARG then the HSMCI_CMDR.
12. Wait for XFRDONE in HSMCI_SR register.
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37.8.8.2 Block Length is Not Multiple of 4. (ROPT field in HSMCI_DMA register set to 0)
Two DMA Transfer descriptors are used to perform the HSMCI block transfer.
1. Use the previous step to configure the HSMCI to perform a READ_MULTIPLE_BLOCK command.
2. Issue a READ_MULTIPLE_BLOCK command.
3. Program the DMA Controller to use a list of descriptors.
a.Read the channel register to choose an available (disabled) channel.
b.Clear any pending interrupts on the channel from the previous DMAC transfer by reading the
DMAC_EBCISR register.
c. For every block of data repeat the following procedure:
d. Program the channel registers in the Memory for the first descriptor. This descriptor will be word ori-
ented. This descriptor is referred to as LLI_W(n) standing for LLI word oriented transfer for block n.
e. The LLI_W(n).DMAC_SADDRx field in memory must be set with the starting address of the
HSMCI_FIFO address.
f. The LLI_W(n).DMAC_DADDRx field in the memory must be word aligned.
g. Program LLI_W(n).DMAC_CTRLAx with the following field’s values:
–DST_WIDTH is set to WORD.
–SRC_WIDTH is set to WORD.
–SCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.
–BTSIZE is programmed with block_length/4. If BTSIZE is zero, this descriptor is skipped later.
h. Program LLI_W(n).DMAC_CTRLBx with the following field’s values:
–DST_INCR is set to INCR.
–SRC_INCR is set to INCR.
–FC field is programmed with peripheral to memory flow control mode.
–SRC_DSCR is set to 0 (descriptor fetch is enabled for the SRC).
–DST_DSCR is set to TRUE (descriptor fetch is disabled for the DST).
–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, the DMA Controller is
able to prefetch data and write HSMCI simultaneously.
i. Program LLI_W(n).DMAC_CFGx register for channel x with the following field’s values:
–FIFOCFG defines the watermark of the DMA channel FIFO.
–DST_REP is set to zero. Address are contiguous.
–SRC_H2SEL is set to true to enable hardware handshaking on the destination.
–SRC_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host
Controller.
j. Program LLI_W(n).DMAC_DSCRx with the address of LLI_B(n) descriptor. And set the DSCRx_IF to
the AHB Layer ID. This operation actually links the Word oriented descriptor on the second byte ori-
ented descriptor. When block_length[1:0] is equal to 0 (multiple of 4) LLI_W(n).DMAC_DSCRx points
to 0, only LLI_W(n) is relevant.
k. Program the channel registers in the Memory for the second descriptor. This descriptor will be byte
oriented. This descriptor is referred to as LLI_B(n), standing for LLI Byte oriented.
l. The LLI_B(n).DMAC_SADDRx field in memory must be set with the starting address of the
HSMCI_FIFO address.
m. The LLI_B(n).DMAC_DADDRx is not relevant if previous word aligned descriptor was enabled. If 1, 2
or 3 bytes are transferred, that address is user defined and not word aligned.
n. Program LLI_B(n).DMAC_CTRLAx with the following field’s values:
–DST_WIDTH is set to BYTE.
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–SRC_WIDTH is set to BYTE.
–SCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.
–BTSIZE is programmed with block_length[1:0]. (last 1, 2, or 3 bytes of the buffer).
o. Program LLI_B(n).DMAC_CTRLBx with the following field’s values:
̶DST_INCR is set to INCR.
̶SRC_INCR is set to INCR.
̶FC field is programmed with peripheral to memory flow control mode.
̶Both SRC_DSCR and DST_DSCR are set to 1 (descriptor fetch is disabled) or Next descriptor
location points to 0.
̶DIF and SIF are set with their respective layer ID. If SIF is different from DIF, the DMA Controller is
able to prefetch data and write HSMCI simultaneously.
p. Program LLI_B(n).DMAC_CFGx memory location for channel x with the following field’s values:
̶FIFOCFG defines the watermark of the DMAC channel FIFO.
̶SRC_H2SEL is set to true to enable hardware handshaking on the destination.
̶SRC_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host Controller
q. Program LLI_B(n).DMAC_DSCR with address of descriptor LLI_W(n+1). If LLI_B(n) is the last
descriptor, then program LLI_B(n).DMAC_DSCR with 0.
r. Program DMAC_CTRLBx register for channel x with 0, its content is updated with the LLI Fetch
operation.
s.Program DMAC_DSCRx with the address of LLI_W(0) if block_length is greater than 4 else with
address of LLI_B(0).
t. Enable Channel x writing one to DMAC_CHER[x]. The DMAC is ready and waiting for request.
4. Enable DMADONE interrupt in the HSMCI_IER register.
5. Poll CBTC[x] bit in the DMAC_EBCISR Register.
6. If a new list of buffers shall be transferred, repeat step 7. Check and handle HSMCI errors.
7. Poll FIFOEMPTY field in the HSMCI_SR.
8. Send The STOP_TRANSMISSION command writing HSMCI_ARG then HSMCI_CMDR.
9. Wait for XFRDONE in HSMCI_SR register.
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37.8.8.3 Block Length is Not a Multiple of 4. (ROPT field in HSMCI_DMA register set to 1)
One DMA Transfer descriptor is used to perform the HSMCI block transfer, the DMA writes a rounded up value to
the nearest multiple of 4.
1. Use the previous step to configure the HSMCI to perform a READ_MULTIPLE_BLOCK.
2. Set the ROPT field to 1 in the HSMCI_DMA register.
3. Issue a READ_MULTIPLE_BLOCK command.
4. Program the DMA controller to use a list of descriptors:
a.Read the channel Register to choose an available (disabled) channel.
b.Clear any pending interrupts on the channel from the previous DMAC transfer by reading the
DMAC_EBCISR register.
c. Program the channel registers in the Memory with the first descriptor. This descriptor will be word ori-
ented. This descriptor is referred to as LLI_W(n), standing for LLI word oriented transfer for block n.
d. The LLI_W(n).DMAC_SADDRx field in memory must be set with the starting address of the
HSMCI_FIFO address.
e. The LLI_W(n).DMAC_DADDRx field in the memory must be word aligned.
f. Program LLI_W(n).DMAC_CTRLAx with the following field’s values:
–DST_WIDTH is set to WORD.
–SRC_WIDTH is set to WORD.
–SCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.
–BTSIZE is programmed with Ceiling(block_length/4).
g. Program LLI_W(n).DMAC_CTRLBx with the following field’s values:
–DST_INCR is set to INCR
–SRC_INCR is set to INCR
–FC field is programmed with peripheral to memory flow control mode.
–SRC_DSCR is set to 0. (descriptor fetch is enabled for the SRC)
–DST_DSCR is set to TRUE. (descriptor fetch is disabled for the DST)
–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, the DMA Controller is
able to prefetch data and write HSMCI simultaneously.
h. Program LLI_W(n).DMAC_CFGx register for channel x with the following field’s values:
–FIFOCFG defines the watermark of the DMA channel FIFO.
–DST_REP is set to zero. Address are contiguous.
–SRC_H2SEL is set to true to enable hardware handshaking on the destination.
–SRC_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host
Controller.
i. Program LLI_W(n).DMAC_DSCRx with the address of LLI_W(n+1) descriptor. And set the DSCRx_IF
to the AHB Layer ID. This operation actually links descriptors together. If LLI_W(n) is the last descrip-
tor then LLI_W(n).DMAC_DSCRx points to 0.
j. Program DMAC_CTRLBx register for channel x with 0. its content is updated with the LLI Fetch
operation.
k. Program DMAC_DSCRx register for channel x with the address of LLI_W(0).
l. Enable Channel x writing one to DMAC_CHER[x]. The DMAC is ready and waiting for request.
5. Poll CBTC[x] bit in the DMAC_EBCISR Register.
6. If a new list of buffers shall be transferred repeat step 7. Check and handle HSMCI errors.
7. Poll FIFOEMPTY field in the HSMCI_SR.
8. Send The STOP_TRANSMISSION command writing the HSMCI_ARG then the HSMCI_CMDR.
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9. Wait for XFRDONE in HSMCI_SR register.
37.9 SD/SDIO Card Operation
The High Speed MultiMedia Card Interface allows processing of SD Memory (Secure Digital Memory Card) and
SDIO (SD Input Output) Card commands.
SD/SDIO cards are based on the Multi Media Card (MMC) format, but are physically slightly thicker and feature
higher data transfer rates, a lock switch on the side to prevent accidental overwriting and security features. The
physical form factor, pin assignment and data transfer protocol are forward-compatible with the High Speed
MultiMedia Card with some additions. SD slots can actually be used for more than flash memory cards. Devices
that support SDIO can use small devices designed for the SD form factor, such as GPS receivers, Wi-Fi or
Bluetooth adapters, modems, barcode readers, IrDA adapters, FM radio tuners, RFID readers, digital cameras
and more.
SD/SDIO is covered by numerous patents and trademarks, and licensing is only available through the Secure
Digital Card Association.
The SD/SDIO Card communication is based on a 9-pin interface (Clock, Command, 4 x Data and 3 x Power lines).
The communication protocol is defined as a part of this specification. The main difference between the SD/SDIO
Card and the High Speed MultiMedia Card is the initialization process.
The SD/SDIO Card Register (HSMCI_SDCR) allows selection of the Card Slot and the data bus width.
The SD/SDIO Card bus allows dynamic configuration of the number of data lines. After power up, by default, the
SD/SDIO Card uses only DAT0 for data transfer. After initialization, the host can change the bus width (number of
active data lines).
37.9.1 SDIO Data Transfer Type
SDIO cards may transfer data in either a multi-byte (1 to 512 bytes) or an optional block format (1 to 511 blocks),
while the SD memory cards are fixed in the block transfer mode. The TRTYP field in the HSMCI Command
Register (HSMCI_CMDR) allows to choose between SDIO Byte or SDIO Block transfer.
The number of bytes/blocks to transfer is set through the BCNT field in the HSMCI Block Register (HSMCI_BLKR).
In SDIO Block mode, the field BLKLEN must be set to the data block size while this field is not used in SDIO Byte
mode.
An SDIO Card can have multiple I/O or combined I/O and memory (called Combo Card). Within a multi-function
SDIO or a Combo card, there are multiple devices (I/O and memory) that share access to the SD bus. In order to
allow the sharing of access to the host among multiple devices, SDIO and combo cards can implement the
optional concept of suspend/resume (Refer to the SDIO Specification for more details). To send a suspend or a
resume command, the host must set the SDIO Special Command field (IOSPCMD) in the HSMCI Command
Register.
37.9.2 SDIO Interrupts
Each function within an SDIO or Combo card may implement interrupts (Refer to the SDIO Specification for more
details). In order to allow the SDIO card to interrupt the host, an interrupt function is added to a pin on the DAT[1]
line to signal the card’s interrupt to the host. An SDIO interrupt on each slot can be enabled through the HSMCI
Interrupt Enable Register. The SDIO interrupt is sampled regardless of the currently selected slot.
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37.10 CE-ATA Operation
CE-ATA maps the streamlined ATA command set onto the MMC interface. The ATA task file is mapped onto MMC
register space.
CE-ATA utilizes five MMC commands:
GO_IDLE_STATE (CMD0): used for hard reset.
STOP_TRANSMISSION (CMD12): causes the ATA command currently executing to be aborted.
FAST_IO (CMD39): Used for single register access to the ATA taskfile registers, 8 bit access only.
RW_MULTIPLE_REGISTERS (CMD60): used to issue an ATA command or to access the control/status
registers.
RW_MULTIPLE_BLOCK (CMD61): used to transfer data for an ATA command.
CE-ATA utilizes the same MMC command sequences for initialization as traditional MMC devices.
37.10.1 Executing an ATA Polling Command
1. Issue READ_DMA_EXT with RW_MULTIPLE_REGISTER (CMD60) for 8kB of DATA.
2. Read the ATA status register until DRQ is set.
3. Issue RW_MULTIPLE_BLOCK (CMD61) to transfer DATA.
4. Read the ATA status register until DRQ && BSY are set to 0.
37.10.2 Executing an ATA Interrupt Command
1. Issue READ_DMA_EXT with RW_MULTIPLE_REGISTER (CMD60) for 8kB of DATA with nIEN field set to
zero to enable the command completion signal in the device.
2. Issue RW_MULTIPLE_BLOCK (CMD61) to transfer DATA.
3. Wait for Completion Signal Received Interrupt.
37.10.3 Aborting an ATA Command
If the host needs to abort an ATA command prior to the completion signal it must send a special command to avoid
potential collision on the command line. The SPCMD field of the HSMCI_CMDR must be set to 3 to issue the CE-
ATA completion Signal Disable Command.
37.10.4 CE-ATA Error Recovery
Several methods of ATA command failure may occur, including:
No response to an MMC command, such as RW_MULTIPLE_REGISTER (CMD60).
CRC is invalid for an MMC command or response.
CRC16 is invalid for an MMC data packet.
ATA Status register reflects an error by setting the ERR bit to one.
The command completion signal does not arrive within a host specified time out period.
Error conditions are expected to happen infrequently. Thus, a robust error recovery mechanism may be used for
each error event. The recommended error recovery procedure after a timeout is:
Issue the command completion signal disable if nIEN was cleared to zero and the RW_MULTIPLE_BLOCK
(CMD61) response has been received.
Issue STOP_TRANSMISSION (CMD12) and successfully receive the R1 response.
Issue a software reset to the CE-ATA device using FAST_IO (CMD39).
If STOP_TRANMISSION (CMD12) is successful, then the device is again ready for ATA commands. However, if
the error recovery procedure does not work as expected or there is another timeout, the next step is to issue
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GO_IDLE_STATE (CMD0) to the device. GO_IDLE_STATE (CMD0) is a hard reset to the device and completely
resets all device states.
Note that after issuing GO_IDLE_STATE (CMD0), all device initialization needs to be completed again. If the CE-
ATA device completes all MMC commands correctly but fails the ATA command with the ERR bit set in the ATA
Status register, no error recovery action is required. The ATA command itself failed implying that the device could
not complete the action requested, however, there was no communication or protocol failure. After the device
signals an error by setting the ERR bit to one in the ATA Status register, the host may attempt to retry the
command.
37.11 HSMCI Boot Operation Mode
In boot operation mode, the processor can read boot data from the slave (MMC device) by keeping the CMD line
low after power-on before issuing CMD1. The data can be read from either the boot area or user area, depending
on register setting. As it is not possible to boot directly on SD-CARD, a preliminary boot code must be stored in
internal Flash.
37.11.1 Boot Procedure, Processor Mode
1. Configure the HSMCI data bus width programming SDCBUS Field in the HSMCI_SDCR register. The
BOOT_BUS_WIDTH field located in the device Extended CSD register must be set accordingly.
2. Set the byte count to 512 bytes and the block count to the desired number of blocks, writing BLKLEN and
BCNT fields of the HSMCI_BLKR Register.
3. Issue the Boot Operation Request command by writing to the HSMCI_CMDR register with SPCMD field set
to BOOTREQ, TRDIR set to READ and TRCMD set to “start data transfer”.
4. The BOOT_ACK field located in the HSMCI_CMDR register must be set to one, if the BOOT_ACK field of
the MMC device located in the Extended CSD register is set to one.
5. Host processor can copy boot data sequentially as soon as the RXRDY flag is asserted.
6. When Data transfer is completed, host processor shall terminate the boot stream by writing the
HSMCI_CMDR register with SPCMD field set to BOOTEND.
37.11.2 Boot Procedure DMA Mode
1. Configure the HSMCI data bus width by programming SDCBUS Field in the HSMCI_SDCR register. The
BOOT_BUS_WIDTH field in the device Extended CSD register must be set accordingly.
2. Set the byte count to 512 bytes and the block count to the desired number of blocks by writing BLKLEN and
BCNT fields of the HSMCI_BLKR Register.
3. Enable DMA transfer in the HSMCI_DMA register.
4. Configure DMA controller, program the total amount of data to be transferred and enable the relevant
channel.
5. Issue the Boot Operation Request command by writing to the HSMCI_CMDR register with SPCND set to
BOOTREQ, TRDIR set to READ and TRCMD set to “start data transfer”.
6. DMA controller copies the boot partition to the memory.
7. When DMA transfer is completed, host processor shall terminate the boot stream by writing the
HSMCI_CMDR register with SPCMD field set to BOOTEND.
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
37.12 HSMCI Transfer Done Timings
37.12.1 Definition
The XFRDONE flag in the HSMCI_SR indicates exactly when the read or write sequence is finished.
37.12.2 Read Access
During a read access, the XFRDONE flag behaves as shown in Figure 37-12.
Figure 37-12. XFRDONE During a Read Access
37.12.3 Write Access
During a write access, the XFRDONE flag behaves as shown in Figure 37-13.
Figure 37-13. XFRDONE During a Write Access
CMD line
HSMCI read CMD
Card response
CMDRDY flag
Data
1st Block Last Block
Not busy flag
XFRDONE flag
The CMDRDY flag is released 8 tbit after the end of the card response.
CMD line
Card response
CMDRDY flag
Data bus - D0
1st Block
Not busy flag
XFRDONE flag
The CMDRDY flag is released 8 tbit after the end of the card response.
Last Block
D0
1st Block Last Block
D0 is tied by the card
D0 is released
HSMCI write CMD
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
940
37.13 Write Protection Registers
To prevent any single software error that may corrupt HSMCI behavior, the entire HSMCI address space from
address offset 0x000 to 0x00FC can be write-protected by setting the WPEN bit in the “HSMCI Write Protect Mode
Register” (HSMCI_WPMR).
If a write access to anywhere in the HSMCI address space from address offset 0x000 to 0x00FC is detected, then
the WPVS flag in the HSMCI Write Protect Status Register (HSMCI_WPSR) is set and the field WPVSRC
indicates in which register the write access has been attempted.
The WPVS flag is reset by writing the HSMCI Write Protect Mode Register (HSMCI_WPMR) with the appropriate
access key, WPKEY.
The protected registers are:
“HSMCI Mode Register” on page 943
“HSMCI Data Timeout Register” on page 945
“HSMCI SDCard/SDIO Register” on page 946
“HSMCI Completion Signal Timeout Register” on page 951
“HSMCI DMA Configuration Register” on page 965
“HSMCI Configuration Register” on page 966
AtmeL
941
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
37.14 High Speed MultiMedia Card Interface (HSMCI) User Interface
Note: 1. The response register can be read by N accesses at the same HSMCI_RSPR or at consecutive addresses (0x20 to 0x2C).
N depends on the size of the response.
Table 37-9. Register Mapping
Offset Register Name Access Reset
0x00 Control Register HSMCI_CR Write –
0x04 Mode Register HSMCI_MR Read-write 0x0
0x08 Data Timeout Register HSMCI_DTOR Read-write 0x0
0x0C SD/SDIO Card Register HSMCI_SDCR Read-write 0x0
0x10 Argument Register HSMCI_ARGR Read-write 0x0
0x14 Command Register HSMCI_CMDR Write –
0x18Block Register HSMCI_BLKR Read-write 0x0
0x1C Completion Signal Timeout Register HSMCI_CSTOR Read-write 0x0
0x20 Response Register(1) HSMCI_RSPR Read 0x0
0x24 Response Register(1) HSMCI_RSPR Read 0x0
0x28 Response Register(1) HSMCI_RSPR Read 0x0
0x2C Response Register(1) HSMCI_RSPR Read 0x0
0x30 Receive Data Register HSMCI_RDR Read 0x0
0x34 Transmit Data Register HSMCI_TDR Write –
0x38 - 0x3C Reserved – – –
0x40 Status Register HSMCI_SR Read 0xC0E5
0x44 Interrupt Enable Register HSMCI_IER Write –
0x48 Interrupt Disable Register HSMCI_IDR Write –
0x4C Interrupt Mask Register HSMCI_IMR Read 0x0
0x50 DMA Configuration Register HSMCI_DMA Read-write 0x00
0x54 Configuration Register HSMCI_CFG Read-write 0x00
0x58-0xE0 Reserved – – –
0xE4 Write Protection Mode Register HSMCI_WPMR Read-write –
0xE8 Write Protection Status Register HSMCI_WPSR Read-only –
0xEC - 0xFC Reserved – – –
0x100-0x1FC Reserved – – –
0x200 FIFO Memory Aperture0 HSMCI_FIFO0 Read-write 0x0
... ... ... ... ...
0x5FC FIFO Memory Aperture255 HSMCI_FIFO255 Read-write 0x0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Warning: AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
942
37.14.1 HSMCI Control Register
Name: HSMCI_CR
Address: 0x40000000
Access: Write-only
• MCIEN: Multi-Media Interface Enable
0: No effect.
1: Enables the Multi-Media Interface if MCDIS is 0.
• MCIDIS: Multi-Media Interface Disable
0: No effect.
1: Disables the Multi-Media Interface.
• PWSEN: Power Save Mode Enable
0: No effect.
1: Enables the Power Saving Mode if PWSDIS is 0.
Warning: Before enabling this mode, the user must set a value different from 0 in the PWSDIV field (Mode Register,
HSMCI_MR).
• PWSDIS: Power Save Mode Disable
0: No effect.
1: Disables the Power Saving Mode.
• SWRST: Software Reset
0: No effect.
1: Resets the HSMCI. A software triggered hardware reset of the HSMCI interface is performed.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
SWRST – – – PWSDIS PWSEN MCIDIS MCIEN
Warning: Warning: AtmeL
943
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
37.14.2 HSMCI Mode Register
Name: HSMCI_MR
Address: 0x40000004
Access: Read-write
This register can only be written if the WPEN bit is cleared in “HSMCI Write Protect Mode Register” on page 967.
• CLKDIV: Clock Divider
High Speed MultiMedia Card Interface clock (MCCK or HSMCI_CK) is Master Clock (MCK) divided by (2*(CLKDIV+1)).
• PWSDIV: Power Saving Divider
High Speed MultiMedia Card Interface clock is divided by 2(PWSDIV) + 1 when entering Power Saving Mode.
Warning: This value must be different from 0 before enabling the Power Save Mode in the HSMCI_CR (HSMCI_PWSEN
bit).
• RDPROOF Read Proof Enable
Enabling Read Proof allows to stop the HSMCI Clock during read access if the internal FIFO is full. This will guarantee data
integrity, not bandwidth.
0: Disables Read Proof.
1: Enables Read Proof.
• WRPROOF Write Proof Enable
Enabling Write Proof allows to stop the HSMCI Clock during write access if the internal FIFO is full. This will guarantee
data integrity, not bandwidth.
0: Disables Write Proof.
1: Enables Write Proof.
• FBYTE: Force Byte Transfer
Enabling Force Byte Transfer allow byte transfers, so that transfer of blocks with a size different from modulo 4 can be
supported.
Warning: BLKLEN value depends on FBYTE.
0: Disables Force Byte Transfer.
1: Enables Force Byte Transfer.
31 30 29 28 27 26 25 24
BLKLEN
23 22 21 20 19 18 17 16
BLKLEN
15 14 13 12 11 10 9 8
– PADV FBYTE WRPROOF RDPROOF PWSDIV
76543210
CLKDIV
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944
• PADV: Padding Value
0: 0x00 value is used when padding data in write transfer.
1: 0xFF value is used when padding data in write transfer.
PADV may be only in manual transfer.
• BLKLEN: Data Block Length
This field determines the size of the data block.
This field is also accessible in the HSMCI Block Register (HSMCI_BLKR).
Bits 16 and 17 must be set to 0 if FBYTE is disabled.
Note: In SDIO Byte mode, BLKLEN field is not used.
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
37.14.3 HSMCI Data Timeout Register
Name: HSMCI_DTOR
Address: 0x40000008
Access: Read-write
This register can only be written if the WPEN bit is cleared in “HSMCI Write Protect Mode Register” on page 967.
• DTOCYC: Data Timeout Cycle Number
These fields determine the maximum number of Master Clock cycles that the HSMCI waits between two data block trans-
fers. It equals (DTOCYC x Multiplier).
• DTOMUL: Data Timeout Multiplier
Multiplier is defined by DTOMUL as shown in the following table:
If the data time-out set by DTOCYC and DTOMUL has been exceeded, the Data Time-out Error flag (DTOE) in the HSMCI
Status Register (HSMCI_SR) raises.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– DTOMUL DTOCYC
Value Name Description
01DTOCYC
1 16 DTOCYC x 16
2 128 DTOCYC x 128
3 256 DTOCYC x 256
4 1024 DTOCYC x 1024
5 4096 DTOCYC x 4096
6 65536 DTOCYC x 65536
7 1048576 DTOCYC x 1048576
AtmeL
SAM3X / SAM3A [DATASHEET]
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946
37.14.4 HSMCI SDCard/SDIO Register
Name: HSMCI_SDCR
Address: 0x4000000C
Access: Read-write
This register can only be written if the WPEN bit is cleared in “HSMCI Write Protect Mode Register” on page 967.
• SDCSEL: SDCard/SDIO Slot
• SDCBUS: SDCard/SDIO Bus Width
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
SDCBUS –––– SDCSEL
Value Name Description
0SLOTASlot A is selected.
1 SLOTB SDCARD/SDIO Slot B selected
2SLOTC–
3SLOTD–
Value Name Description
01
1 bit
1–
Reserved
244 bit
388 bit
AtmeL
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
37.14.5 HSMCI Argument Register
Name: HSMCI_ARGR
Address: 0x40000010
Access: Read-write
• ARG: Command Argument
31 30 29 28 27 26 25 24
ARG
23 22 21 20 19 18 17 16
ARG
15 14 13 12 11 10 9 8
ARG
76543210
ARG
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948
37.14.6 HSMCI Command Register
Name: HSMCI_CMDR
Address: 0x40000014
Access: Write-only
This register is write-protected while CMDRDY is 0 in HSMCI_SR. If an Interrupt command is sent, this register is only
writeable by an interrupt response (field SPCMD). This means that the current command execution cannot be interrupted
or modified.
• CMDNB: Command Number
This is the command index.
• RSPTYP: Response Type
• SPCMD: Special Command
31 30 29 28 27 26 25 24
––––BOOT_ACKATACS IOSPCMD
23 22 21 20 19 18 17 16
– – TRTYP TRDIR TRCMD
15 14 13 12 11 10 9 8
– – – MAXLAT OPDCMD SPCMD
76543210
RSPTYP CMDNB
Value Name Description
0 NORESP No response.
1 48_BIT 48-bit response.
2 136_BIT 136-bit response.
3 R1B R1b response type
Value Name Description
0 STD Not a special CMD.
1INIT
Initialization CMD:
74 clock cycles for initialization sequence.
2 SYNC Synchronized CMD:
Wait for the end of the current data block transfer before sending the pending command.
3CE_ATA
CE-ATA Completion Signal disable Command.
The host cancels the ability for the device to return a command completion signal on the command line.
4IT_CMD
Interrupt command:
Corresponds to the Interrupt Mode (CMD40).
5 IT_RESP Interrupt response:
Corresponds to the Interrupt Mode (CMD40).
6BOR
Boot Operation Request.
Start a boot operation mode, the host processor can read boot data from the MMC device directly.
7EBO
End Boot Operation.
This command allows the host processor to terminate the boot operation mode.
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• OPDCMD: Open Drain Command
0 (PUSHPULL) = Push pull command.
1 (OPENDRAIN) = Open drain command.
• MAXLAT: Max Latency for Command to Response
0 (5) = 5-cycle max latency.
1 (64) = 64-cycle max latency.
• TRCMD: Transfer Command
• TRDIR: Transfer Direction
0 (WRITE) = Write.
1 (READ) = Read.
• TRTYP: Transfer Type
• IOSPCMD: SDIO Special Command
• ATACS: ATA with Command Completion Signal
0 (NORMAL) = Normal operation mode.
1 (COMPLETION) = This bit indicates that a completion signal is expected within a programmed amount of time
(HSMCI_CSTOR).
• BOOT_ACK: Boot Operation Acknowledge.
The master can choose to receive the boot acknowledge from the slave when a Boot Request command is issued. When
set to one this field indicates that a Boot acknowledge is expected within a programmable amount of time defined with
DTOMUL and DTOCYC fields located in the HSMCI_DTOR register. If the acknowledge pattern is not received then an
acknowledge timeout error is raised. If the acknowledge pattern is corrupted then an acknowledge pattern error is set.
Value Name Description
0 NO_DATA No data transfer
1 START_DATA Start data transfer
2 STOP_DATA Stop data transfer
3–Reserved
Value Name Description
0 SINGLE MMC/SDCard Single Block
1 MULTIPLE MMC/SDCard Multiple Block
2 STREAM MMC Stream
4 BYTE SDIO Byte
5 BLOCK SDIO Block
Value Name Description
0 STD Not an SDIO Special Command
1 SUSPEND SDIO Suspend Command
2 RESUME SDIO Resume Command
Warning: AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
950
37.14.7 HSMCI Block Register
Name: HSMCI_BLKR
Address: 0x40000018
Access: Read-write
• BCNT: MMC/SDIO Block Count - SDIO Byte Count
This field determines the number of data byte(s) or block(s) to transfer.
The transfer data type and the authorized values for BCNT field are determined by the TRTYP field in the HSMCI Com-
mand Register (HSMCI_CMDR):
Warning: In SDIO Byte and Block modes, writing to the 7 last bits of BCNT field is forbidden and may lead to unpredictable
results.
• BLKLEN: Data Block Length
This field determines the size of the data block.
This field is also accessible in the HSMCI Mode Register (HSMCI_MR).
Bits 16 and 17 must be set to 0 if FBYTE is disabled.
Note: In SDIO Byte mode, BLKLEN field is not used.
31 30 29 28 27 26 25 24
BLKLEN
23 22 21 20 19 18 17 16
BLKLEN
15 14 13 12 11 10 9 8
BCNT
76543210
BCNT
Value Name Description
0MULTIPLE MMC/SDCARD Multiple Block
From 1 to 65635: Value 0 corresponds to an infinite block transfer.
4 BYTE
SDIO Byte
From 1 to 512 bytes: Value 0 corresponds to a 512-byte transfer.
Values from 0x200 to 0xFFFF are forbidden.
5BLOCK
SDIO Block
From 1 to 511 blocks: Value 0 corresponds to an infinite block transfer.
Values from 0x200 to 0xFFFF are forbidden.
AtmeL
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
37.14.8 HSMCI Completion Signal Timeout Register
Name: HSMCI_CSTOR
Address: 0x4000001C
Access: Read-write
This register can only be written if the WPEN bit is cleared in “HSMCI Write Protect Mode Register” on page 967.
• CSTOCYC: Completion Signal Timeout Cycle Number
These fields determine the maximum number of Master Clock cycles that the HSMCI waits between two data block trans-
fers. Its value is calculated by (CSTOCYC x Multiplier).
• CSTOMUL: Completion Signal Timeout Multiplier
These fields determine the maximum number of Master Clock cycles that the HSMCI waits between two data block trans-
fers. Its value is calculated by (CSTOCYC x Multiplier).
These fields determine the maximum number of Master Clock cycles that the HSMCI waits between the end of the data
transfer and the assertion of the completion signal. The data transfer comprises data phase and the optional busy phase. If
a non-DATA ATA command is issued, the HSMCI starts waiting immediately after the end of the response until the comple-
tion signal.
Multiplier is defined by CSTOMUL as shown in the following table:
If the data time-out set by CSTOCYC and CSTOMUL has been exceeded, the Completion Signal Time-out Error flag
(CSTOE) in the HSMCI Status Register (HSMCI_SR) raises.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– CSTOMUL CSTOCYC
Value Name Description
0 1 CSTOCYC x 1
1 16 CSTOCYC x 16
2 128 CSTOCYC x 128
3 256 CSTOCYC x 256
4 1024 CSTOCYC x 1024
5 4096 CSTOCYC x 4096
6 65536 CSTOCYC x 65536
7 1048576 CSTOCYC x 1048576
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
952
37.14.9 HSMCI Response Register
Name: HSMCI_RSPR
Address: 0x40000020
Access: Read-only
• RSP: Response
Note: 1. The response register can be read by N accesses at the same HSMCI_RSPR or at consecutive addresses (0x20 to 0x2C).
N depends on the size of the response.
31 30 29 28 27 26 25 24
RSP
23 22 21 20 19 18 17 16
RSP
15 14 13 12 11 10 9 8
RSP
76543210
RSP
AtmeL
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SAM3X / SAM3A [DATASHEET]
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37.14.10 HSMCI Receive Data Register
Name: HSMCI_RDR
Address: 0x40000030
Access: Read-only
• DATA: Data to Read
31 30 29 28 27 26 25 24
DATA
23 22 21 20 19 18 17 16
DATA
15 14 13 12 11 10 9 8
DATA
76543210
DATA
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
954
37.14.11 HSMCI Transmit Data Register
Name: HSMCI_TDR
Address: 0x40000034
Access: Write-only
• DATA: Data to Write
31 30 29 28 27 26 25 24
DATA
23 22 21 20 19 18 17 16
DATA
15 14 13 12 11 10 9 8
DATA
76543210
DATA
AtmeL
955
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
37.14.12 HSMCI Status Register
Name: HSMCI_SR
Address: 0x40000040
Access: Read-only
• CMDRDY: Command Ready
0: A command is in progress.
1: The last command has been sent. Cleared when writing in the HSMCI_CMDR.
• RXRDY: Receiver Ready
0: Data has not yet been received since the last read of HSMCI_RDR.
1: Data has been received since the last read of HSMCI_RDR.
• TXRDY: Transmit Ready
0: The last data written in HSMCI_TDR has not yet been transferred in the Shift Register.
1: The last data written in HSMCI_TDR has been transferred in the Shift Register.
• BLKE: Data Block Ended
This flag must be used only for Write Operations.
0: A data block transfer is not yet finished. Cleared when reading the HSMCI_SR.
1: A data block transfer has ended, including the CRC16 Status transmission.
the flag is set for each transmitted CRC Status.
Refer to the MMC or SD Specification for more details concerning the CRC Status.
• DTIP: Data Transfer in Progress
0: No data transfer in progress.
1: The current data transfer is still in progress, including CRC16 calculation. Cleared at the end of the CRC16 calculation.
31 30 29 28 27 26 25 24
UNRE OVRE ACKRCVE ACKRCV XFRDONE FIFOEMPTY DMADONE BLKOVRE
23 22 21 20 19 18 17 16
CSTOE DTOE DCRCE RTOE RENDE RCRCE RDIRE RINDE
15 14 13 12 11 10 9 8
– – CSRCV SDIOWAIT – – SDIO IRQ for
Slot B SDIO IRQ for
Slot A
76543210
– – NOTBUSY DTIP BLKE TXRDY RXRDY CMDRDY
AtmeL
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956
• NOTBUSY: HSMCI Not Busy
This flag must be used only for Write Operations.
A block write operation uses a simple busy signalling of the write operation duration on the data (DAT0) line: during a data
transfer block, if the card does not have a free data receive buffer, the card indicates this condition by pulling down the data
line (DAT0) to LOW. The card stops pulling down the data line as soon as at least one receive buffer for the defined data
transfer block length becomes free.
The NOTBUSY flag allows to deal with these different states.
0: The HSMCI is not ready for new data transfer. Cleared at the end of the card response.
1: The HSMCI is ready for new data transfer. Set when the busy state on the data line has ended. This corresponds to a
free internal data receive buffer of the card.
Refer to the MMC or SD Specification for more details concerning the busy behavior.
• SDIOIRQA: SDIO Interrupt for Slot A
0: No interrupt detected on SDIO Slot A.
1: An SDIO Interrupt on Slot A occurred. Cleared when reading the HSMCI_SR.
• SDIOIRQB: SDIO Interrupt for Slot B
0: No interrupt detected on SDIO Slot B.
1: An SDIO Interrupt on Slot B occurred. Cleared when reading the HSMCI_SR.
• SDIOWAIT: SDIO Read Wait Operation Status
0: Normal Bus operation.
1: The data bus has entered IO wait state.
• CSRCV: CE-ATA Completion Signal Received
0: No completion signal received since last status read operation.
1: The device has issued a command completion signal on the command line. Cleared by reading in the HSMCI_SR
register.
• RINDE: Response Index Error
0: No error.
1: A mismatch is detected between the command index sent and the response index received. Cleared when writing in the
HSMCI_CMDR.
• RDIRE: Response Direction Error
0: No error.
1: The direction bit from card to host in the response has not been detected.
• RCRCE: Response CRC Error
0: No error.
1: A CRC7 error has been detected in the response. Cleared when writing in the HSMCI_CMDR.
• RENDE: Response End Bit Error
0: No error.
1: The end bit of the response has not been detected. Cleared when writing in the HSMCI_CMDR.
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• RTOE: Response Time-out Error
0: No error.
1: The response time-out set by MAXLAT in the HSMCI_CMDR has been exceeded. Cleared when writing in the
HSMCI_CMDR.
• DCRCE: Data CRC Error
0: No error.
1: A CRC16 error has been detected in the last data block. Cleared by reading in the HSMCI_SR register.
• DTOE: Data Time-out Error
0: No error.
1: The data time-out set by DTOCYC and DTOMUL in HSMCI_DTOR has been exceeded. Cleared by reading in the
HSMCI_SR register.
• CSTOE: Completion Signal Time-out Error
0: No error.
1: The completion signal time-out set by CSTOCYC and CSTOMUL in HSMCI_CSTOR has been exceeded. Cleared by
reading in the HSMCI_SR register. Cleared by reading in the HSMCI_SR register.
• BLKOVRE: DMA Block Overrun Error
0: No error.
1: A new block of data is received and the DMA controller has not started to move the current pending block, a block over-
run is raised. Cleared by reading in the HSMCI_SR register.
• DMADONE: DMA Transfer done
0: DMA buffer transfer has not completed since the last read of HSMCI_SR register.
1: DMA buffer transfer has completed.
• FIFOEMPTY: FIFO empty flag
0: FIFO contains at least one byte.
1: FIFO is empty.
• XFRDONE: Transfer Done flag
0: A transfer is in progress.
1: Command register is ready to operate and the data bus is in the idle state.
• ACKRCV: Boot Operation Acknowledge Received
0: No Boot acknowledge received since the last read of the status register.
1: A Boot acknowledge signal has been received. Cleared by reading the HSMCI_SR register.
• ACKRCVE: Boot Operation Acknowledge Error
0: No error
1: Corrupted Boot Acknowledge signal received.
AtmeL
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958
• OVRE: Overrun
0: No error.
1: At least one 8-bit received data has been lost (not read). Cleared when sending a new data transfer command.
When FERRCTRL in HSMCI_CFG is set to 1, OVRE becomes reset after read.
• UNRE: Underrun
0: No error.
1: At least one 8-bit data has been sent without valid information (not written). Cleared when sending a new data transfer
command or when setting FERRCTRL in HSMCI_CFG to 1.
When FERRCTRL in HSMCI_CFG is set to 1, UNRE becomes reset after read.
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37.14.13 HSMCI Interrupt Enable Register
Name: HSMCI_IER
Address: 0x40000044
Access: Write-only
• CMDRDY: Command Ready Interrupt Enable
• RXRDY: Receiver Ready Interrupt Enable
• TXRDY: Transmit Ready Interrupt Enable
• BLKE: Data Block Ended Interrupt Enable
• DTIP: Data Transfer in Progress Interrupt Enable
• NOTBUSY: Data Not Busy Interrupt Enable
• SDIOIRQA: SDIO Interrupt for Slot A Interrupt Enable
• SDIOIRQB: SDIO Interrupt for Slot B Interrupt Enable
• SDIOIRQD: SDIO Interrupt for Slot D Interrupt Enable
• SDIOWAIT: SDIO Read Wait Operation Status Interrupt Enable
• CSRCV: Completion Signal Received Interrupt Enable
• RINDE: Response Index Error Interrupt Enable
• RDIRE: Response Direction Error Interrupt Enable
• RCRCE: Response CRC Error Interrupt Enable
• RENDE: Response End Bit Error Interrupt Enable
• RTOE: Response Time-out Error Interrupt Enable
• DCRCE: Data CRC Error Interrupt Enable
• DTOE: Data Time-out Error Interrupt Enable
• CSTOE: Completion Signal Timeout Error Interrupt Enable
31 30 29 28 27 26 25 24
UNRE OVRE ACKRCVE ACKRCV XFRDONE FIFOEMPTY DMADONE BLKOVRE
23 22 21 20 19 18 17 16
CSTOE DTOE DCRCE RTOE RENDE RCRCE RDIRE RINDE
15 14 13 12 11 10 9 8
– – CSRCV SDIOWAIT – – SDIO IRQ for
Slot B SDIO IRQ for
Slot A
76543210
– – NOTBUSY DTIP BLKE TXRDY RXRDY CMDRDY
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• BLKOVRE: DMA Block Overrun Error Interrupt Enable
• DMADONE: DMA Transfer completed Interrupt Enable
• FIFOEMPTY: FIFO empty Interrupt enable
• XFRDONE: Transfer Done Interrupt enable
• ACKRCV: Boot Acknowledge Interrupt Enable
• ACKRCVE: Boot Acknowledge Error Interrupt Enable
• OVRE: Overrun Interrupt Enable
• UNRE: Underrun Interrupt Enable
0: No effect.
1: Enables the corresponding interrupt.
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37.14.14 HSMCI Interrupt Disable Register
Name: HSMCI_IDR
Address: 0x40000048
Access: Write-only
• CMDRDY: Command Ready Interrupt Disable
• RXRDY: Receiver Ready Interrupt Disable
• TXRDY: Transmit Ready Interrupt Disable
• BLKE: Data Block Ended Interrupt Disable
• DTIP: Data Transfer in Progress Interrupt Disable
• NOTBUSY: Data Not Busy Interrupt Disable
• SDIOIRQA: SDIO Interrupt for Slot A Interrupt Disable
• SDIOIRQB: SDIO Interrupt for Slot B Interrupt Disable
• SDIOWAIT: SDIO Read Wait Operation Status Interrupt Disable
• CSRCV: Completion Signal received interrupt Disable
• RINDE: Response Index Error Interrupt Disable
• RDIRE: Response Direction Error Interrupt Disable
• RCRCE: Response CRC Error Interrupt Disable
• RENDE: Response End Bit Error Interrupt Disable
• RTOE: Response Time-out Error Interrupt Disable
• DCRCE: Data CRC Error Interrupt Disable
• DTOE: Data Time-out Error Interrupt Disable
• CSTOE: Completion Signal Time out Error Interrupt Disable
• BLKOVRE: DMA Block Overrun Error Interrupt Disable
31 30 29 28 27 26 25 24
UNRE OVRE ACKRCVE ACKRCV XFRDONE FIFOEMPTY DMADONE BLKOVRE
23 22 21 20 19 18 17 16
CSTOE DTOE DCRCE RTOE RENDE RCRCE RDIRE RINDE
15 14 13 12 11 10 9 8
– – CSRCV SDIOWAIT – – SDIO IRQ for
Slot B SDIO IRQ for
Slot A
76543210
– – NOTBUSY DTIP BLKE TXRDY RXRDY CMDRDY
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• DMADONE: DMA Transfer completed Interrupt Disable
• FIFOEMPTY: FIFO empty Interrupt Disable
• XFRDONE: Transfer Done Interrupt Disable
• ACKRCV: Boot Acknowledge Interrupt Disable
• ACKRCVE: Boot Acknowledge Error Interrupt Disable
• OVRE: Overrun Interrupt Disable
• UNRE: Underrun Interrupt Disable
0: No effect.
1: Disables the corresponding interrupt.
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37.14.15 HSMCI Interrupt Mask Register
Name: HSMCI_IMR
Address: 0x4000004C
Access: Read-only
• CMDRDY: Command Ready Interrupt Mask
• RXRDY: Receiver Ready Interrupt Mask
• TXRDY: Transmit Ready Interrupt Mask
• BLKE: Data Block Ended Interrupt Mask
• DTIP: Data Transfer in Progress Interrupt Mask
• NOTBUSY: Data Not Busy Interrupt Mask
• SDIOIRQA: SDIO Interrupt for Slot A Interrupt Mask
• SDIOIRQB: SDIO Interrupt for Slot B Interrupt Mask
• SDIOWAIT: SDIO Read Wait Operation Status Interrupt Mask
• CSRCV: Completion Signal Received Interrupt Mask
• RINDE: Response Index Error Interrupt Mask
• RDIRE: Response Direction Error Interrupt Mask
• RCRCE: Response CRC Error Interrupt Mask
• RENDE: Response End Bit Error Interrupt Mask
• RTOE: Response Time-out Error Interrupt Mask
• DCRCE: Data CRC Error Interrupt Mask
• DTOE: Data Time-out Error Interrupt Mask
• CSTOE: Completion Signal Time-out Error Interrupt Mask
• BLKOVRE: DMA Block Overrun Error Interrupt Mask
31 30 29 28 27 26 25 24
UNRE OVRE ACKRCVE ACKRCV XFRDONE FIFOEMPTY DMADONE BLKOVRE
23 22 21 20 19 18 17 16
CSTOE DTOE DCRCE RTOE RENDE RCRCE RDIRE RINDE
15 14 13 12 11 10 9 8
– – CSRCV SDIOWAIT – – SDIO IRQ for
Slot B SDIO IRQ for
Slot A
76543210
– – NOTBUSY DTIP BLKE TXRDY RXRDY CMDRDY
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• DMADONE: DMA Transfer Completed Interrupt Mask
• FIFOEMPTY: FIFO Empty Interrupt Mask
• XFRDONE: Transfer Done Interrupt Mask
• ACKRCV: Boot Operation Acknowledge Received Interrupt Mask
• ACKRCVE: Boot Operation Acknowledge Error Interrupt Mask
• OVRE: Overrun Interrupt Mask
• UNRE: Underrun Interrupt Mask
0: The corresponding interrupt is not enabled.
1: The corresponding interrupt is enabled.
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37.14.16 HSMCI DMA Configuration Register
Name: HSMCI_DMA
Address: 0x40000050
Access: Read-write
This register can only be written if the WPEN bit is cleared in “HSMCI Write Protect Mode Register” on page 967.
• OFFSET: DMA Write Buffer Offset
This field indicates the number of discarded bytes when the DMA writes the first word of the transfer.
• CHKSIZE: DMA Channel Read and Write Chunk Size
The CHKSIZE field indicates the number of data available when the DMA chunk transfer request is asserted.
• DMAEN: DMA Hardware Handshaking Enable
0: DMA interface is disabled.
1: DMA Interface is enabled.
Note: To avoid unpredictable behavior, DMA hardware handshaking must be disabled when CPU transfers are performed.
• ROPT: Read Optimization with padding
0: BLKLEN bytes are moved from the Memory Card to the system memory, two DMA descriptors are used when the trans-
fer size is not a multiple of 4.
1: Ceiling(BLKLEN/4) * 4 bytes are moved from the Memory Card to the system memory, only one DMA descriptor is used.
31 30 29 28 27 26 25 24
––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––ROPT–––DMAEN
76543210
–––CHKSIZE–– OFFSET
Value Name Description
0 1 1 data available
1 4 4 data available
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37.14.17 HSMCI Configuration Register
Name: HSMCI_CFG
Address: 0x40000054
Access: Read-write
This register can only be written if the WPEN bit is cleared in “HSMCI Write Protect Mode Register” on page 967.
• FIFOMODE: HSMCI Internal FIFO control mode
0: A write transfer starts when a sufficient amount of data is written into the FIFO.
When the block length is greater than or equal to 3/4 of the HSMCI internal FIFO size, then the write transfer starts as soon
as half the FIFO is filled. When the block length is greater than or equal to half the internal FIFO size, then the write trans-
fer starts as soon as one quarter of the FIFO is filled. In other cases, the transfer starts as soon as the total amount of data
is written in the internal FIFO.
1: A write transfer starts as soon as one data is written into the FIFO.
• FERRCTRL: Flow Error flag reset control mode
0: When an underflow/overflow condition flag is set, a new Write/Read command is needed to reset the flag.
1: When an underflow/overflow condition flag is set, a read status resets the flag.
• HSMODE: High Speed Mode
0: Default bus timing mode.
1: If set to one, the host controller outputs command line and data lines on the rising edge of the card clock. The Host
driver shall check the high speed support in the card registers.
• LSYNC: Synchronize on the last block
0: The pending command is sent at the end of the current data block.
1: The pending command is sent at the end of the block transfer when the transfer length is not infinite. (block count shall
be different from zero)
31 30 29 28 27 26 25 24
––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––LSYNC–––HSMODE
76543210
– – – FERRCTRL – – – FIFOMODE
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37.14.18 HSMCI Write Protect Mode Register
Name: HSMCI_WPMR
Address: 0x400000E4
Access: Read-write
• WP_EN: Write Protection Enable
0: Disables the Write Protection if WP_KEY corresponds to 0x4D4349 (“MCI’ in ASCII).
1: Enables the Write Protection if WP_KEY corresponds to 0x4D4349 (“MCI’ in ASCII).
• WP_KEY: Write Protection Key password
Should be written at value 0x4D4349 (ASCII code for “MCI”). Writing any other value in this field has no effect.
Protects the registers:
•“HSMCI Mode Register” on page 943
•“HSMCI Data Timeout Register” on page 945
•“HSMCI SDCard/SDIO Register” on page 946
•“HSMCI Completion Signal Timeout Register” on page 951
•“HSMCI DMA Configuration Register” on page 965
•“HSMCI Configuration Register” on page 966
31 30 29 28 27 26 25 24
WP_KEY (0x4D => “M”)
23 22 21 20 19 18 17 16
WP_KEY (0x43 => C”)
15 14 13 12 11 10 9 8
WP_KEY (0x49 => “I”)
76543210
WP_EN
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37.14.19 HSMCI Write Protect Status Register
Name: HSMCI_WPSR
Address: 0x400000E8
Access: Read-only
• WP_VS: Write Protection Violation Status
• WP_VSRC: Write Protection Violation SouRCe
When WPVS is active, this field indicates the write-protected register (through address offset or code) in which a write
access has been attempted.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
WP_VSRC
15 14 13 12 11 10 9 8
WP_VSRC
76543210
–––– WP_VS
Value Name Description
0NONE
No Write Protection Violation occurred since the last read of this
register (WP_SR)
1WRITE
Write Protection detected unauthorized attempt to write a control
register had occurred (since the last read.)
2 RESET Software reset had been performed while Write Protection was
enabled (since the last read).
3BOTH
Both Write Protection violation and software reset with Write
Protection enabled have occurred since the last read.
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37.14.20 HSMCI FIFOx Memory Aperture
Name: HSMCI_FIFOx[x=0..255]
Address: 0x40000200
Access: Read-write
• DATA: Data to Read or Data to Write
31 30 29 28 27 26 25 24
DATA
23 22 21 20 19 18 17 16
DATA
15 14 13 12 11 10 9 8
DATA
76543210
DATA
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38. Pulse Width Modulation (PWM)
38.1 Description
The PWM macrocell controls 8 channels independently. Each channel controls two complementary square output
waveforms. Characteristics of the output waveforms such as period, duty-cycle, polarity and dead-times (also
called dead-bands or non-overlapping times) are configured through the user interface. Each channel selects and
uses one of the clocks provided by the clock generator. The clock generator provides several clocks resulting from
the division of the PWM master clock (MCK).
All PWM macrocell accesses are made through registers mapped on the peripheral bus. All channels integrate a
double buffering system in order to prevent an unexpected output waveform while modifying the period, the duty-
cycle or the dead-times.
Channels can be linked together as synchronous channels to be able to update their duty-cycle or dead-times at
the same time.
The update of duty-cycles of synchronous channels can be performed by the Peripheral DMA Controller Channel
(PDC) which offers buffer transfer without processor Intervention.
The PWM macrocell provides 8 independent comparison units capable of comparing a programmed value to the
counter of the synchronous channels (counter of channel 0). These comparisons are intended to generate
software interrupts, to trigger pulses on the 2 independent event lines (in order to synchronize ADC conversions
with a lot of flexibility independently of the PWM outputs), and to trigger PDC transfer requests.
The PWM outputs can be overridden synchronously or asynchronously to their channel counter.
The PWM block provides a fault protection mechanism with 6 fault inputs, capable of detecting a fault condition
and to override the PWM outputs asynchronously.
For safety usage, some control registers are write-protected.
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38.2 Embedded Characteristics
8 Channels
Common Clock Generator Providing Thirteen Different Clocks
̶A Modulo n Counter Providing Eleven Clocks
̶Two Independent Linear Dividers Working on Modulo n Counter Outputs
Independent Channels
̶Independent 16-bit Counter for Each Channel
̶Independent Complementary Outputs with 12-bit Dead-Time Generator (Also Called Dead-Band or
Non-Overlapping Time) for Each Channel
̶Independent Enable Disable Command for Each Channel
̶Independent Clock Selection for Each Channel
̶Independent Period, Duty-Cycle and Dead-Time for Each Channel
̶Independent Double Buffering of Period, Duty-Cycle and Dead-Times for Each Channel
̶Independent Programmable Selection of The Output Waveform Polarity for Each Channel
̶Independent Programmable Center or Left Aligned Output Waveform for Each Channel
̶Independent Output Override for Each Channel
4 2-bit Gray Up/Down Channels for Stepper Motor Control
Synchronous Channel Mode
̶Synchronous Channels Share the Same Counter
̶Mode to Update the Synchronous Channels Registers after a Programmable Number of Periods
̶Synchronous Channels Supports Connection of one Peripheral DMA Controller Channel (PDC) Which
Offers Buffer Transfer Without Processor Intervention To Update Duty-Cycle Registers
2 Independent Events Lines Intended to Synchronize ADC Conversions
8 Comparison Units Intended to Generate Interrupts, Pulses on Event Lines and PDC Transfer Requests
6 Programmable Fault Inputs Providing an Asynchronous Protection of PWM Outputs
̶User Driven through PIO inputs
̶PMC Driven when Crystal Oscillator Clock Fails
̶ADC Controller Driven through Configurable Comparison Function
̶Timer/Counter Driven through Configurable Comparison Function
Write-Protect Registers
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38.3 Block Diagram
Figure 38-1. Pulse Width Modulation Controller Block Diagram
38.4 I/O Lines Description
Each channel outputs two complementary external I/O lines.
APB
ADC
Comparison
Units
PDC
NVIC
Interrupt Generator
event line 0
event line 1
Events
Generator event line x
Clock
Selector Counter
Channel 0
Duty-Cycle
Period
Update
APB
Interface
CLOCK
Generator
PIO
PMC
Comparator
Clock
Selector
Channel x
Dead-Time
Generator Output
Override
OCx
DTOHx
DTOLx
Fault
Protection
OOOHx PWMHx
PWMLx
OOOLx
Counter
Channel x
Duty-Cycle
Period
Update
MUX
SYNCx
Comparator
Channel 0
Dead-Time
Generator Output
Override
OC0
DTOH0
DTOL0
Fault
Protection
OOOH0 PWMH0
PWML0
OOOL0
PWM Controller
PWMHx
PWMLx
PWMH0
PWML0
PIO
MCK
PWMFI0
PWMFIx
Table 38-1. I/O Line Description
Name Description Type
PWMHx PWM Waveform Output High for channel x Output
PWMLx PWM Waveform Output Low for channel x Output
PWMFIx PWM Fault Input x Input
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38.5 Product Dependencies
38.5.1 I/O Lines
The pins used for interfacing the PWM are multiplexed with PIO lines. The programmer must first program the PIO
controller to assign the desired PWM pins to their peripheral function. If I/O lines of the PWM are not used by the
application, they can be used for other purposes by the PIO controller.
All of the PWM outputs may or may not be enabled. If an application requires only four channels, then only four
PIO lines will be assigned to PWM outputs.
Table 38-2. I/O Lines
Instance Signal I/O Line Peripheral
PWM PWMFI0 PA5 B
PWM PWMFI1 PA3 B
PWM PWMFI2 PD6 B
PWM PWMH0 PA8 B
PWM PWMH0 PB12 B
PWM PWMH0 PC3 B
PWM PWMH0 PE15 A
PWM PWMH1 PA19 B
PWM PWMH1 PB13 B
PWM PWMH1 PC5 B
PWM PWMH1 PE16 A
PWM PWMH2 PA13 B
PWM PWMH2 PB14 B
PWM PWMH2 PC7 B
PWM PWMH3 PA9 B
PWM PWMH3 PB15 B
PWM PWMH3 PC9 B
PWM PWMH3 PF3 A
PWM PWMH4 PC20 B
PWM PWMH4 PE20 A
PWM PWMH5 PC19 B
PWM PWMH5 PE22 A
PWM PWMH6 PC18 B
PWM PWMH6 PE24 A
PWM PWMH7 PE26 A
PWM PWML0 PA21 B
PWM PWML0 PB16 B
PWM PWML0 PC2 B
PWM PWML0 PE18 A
PWM PWML1 PA12 B
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38.5.2 Power Management
The PWM is not continuously clocked. The programmer must first enable the PWM clock in the Power
Management Controller (PMC) before using the PWM. However, if the application does not require PWM
operations, the PWM clock can be stopped when not needed and be restarted later. In this case, the PWM will
resume its operations where it left off.
In the PWM description, Master Clock (MCK) is the clock of the peripheral bus to which the PWM is connected.
38.5.3 Interrupt Sources
The PWM interrupt line is connected on one of the internal sources of the Nested Vectored Interrupt Controller
(NVIC). Using the PWM interrupt requires the NVIC to be programmed first.
38.5.4 Fault Inputs
The PWM has the FAULT inputs connected to the different modules. Please refer to the implementation of these
module within the product for detailed information about the fault generation procedure. The PWM receives faults
from PIO inputs, PMC, ADC controller, and Timer/Counters
PWM PWML1 PB17 B
PWM PWML1 PC4 B
PWM PWML2 PA20 B
PWM PWML2 PB18 B
PWM PWML2 PC6 B
PWM PWML2 PE17 A
PWM PWML3 PA0 B
PWM PWML3 PB19 B
PWM PWML3 PC8 B
PWM PWML4 PC21 B
PWM PWML4 PE19 A
PWM PWML5 PC22 B
PWM PWML5 PE21 A
PWM PWML6 PC23 B
PWM PWML6 PE23 A
PWM PWML7 PC24 B
PWM PWML7 PE25 A
Table 38-2. I/O Lines (Continued)
Table 38-3. Peripheral IDs
Instance ID
PWM 36
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Note: 1. FPOL bit in PWMC_FMR.
Table 38-4. Fault Inputs
Fault Inputs External PWM Fault Input Number Polarity Level(1) Fault Input ID
PA5 PWMFI0 User Defined 0
PA3 PWMFI1 User Defined 1
PD6 PWMFI2 User Defined 2
MAIN OSC – 1 3
ADC – 1 4
Timer0 – 1 5
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38.6 Functional Description
The PWM macrocell is primarily composed of a clock generator module and 8 channels.
Clocked by the master clock (MCK), the clock generator module provides 13 clocks.
Each channel can independently choose one of the clock generator outputs.
Each channel generates an output waveform with attributes that can be defined independently for each
channel through the user interface registers.
38.6.1 PWM Clock Generator
Figure 38-2. Functional View of the Clock Generator Block Diagram
The PWM master clock (MCK) is divided in the clock generator module to provide different clocks available for all
channels. Each channel can independently select one of the divided clocks.
The clock generator is divided in three blocks:
̶a modulo n counter which provides 11 clocks: FMCK, FMCK/2, FMCK/4, FMCK/8, FMCK/16, FMCK/32,
FMCK/64, FMCK/128, FMCK/256, FMCK/512, FMCK/1024
̶two linear dividers (1, 1/2, 1/3, ... 1/255) that provide two separate clocks: clkA and clkB
Each linear divider can independently divide one of the clocks of the modulo n counter. The selection of the clock
to be divided is made according to the PREA (PREB) field of the PWM Clock register (PWM_CLK). The resulting
clock clkA (clkB) is the clock selected divided by DIVA (DIVB) field value.
modulo n counter
MCK/2
MCK/4
MCK/16
MCK/32
MCK/64
MCK/8
Divider A clkA
DIVA
PWM_MR
MCK
MCK/128
MCK/256
MCK/512
MCK/1024
PREA
Divider B clkB
DIVB
PWM_MR
PREB
MCK
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After a reset of the PWM controller, DIVA (DIVB) and PREA (PREB) are set to 0. This implies that after reset clkA
(clkB) are turned off.
At reset, all clocks provided by the modulo n counter are turned off except clock ”MCK”. This situation is also true
when the PWM master clock is turned off through the Power Management Controller.
CAUTION:
Before using the PWM macrocell, the programmer must first enable the PWM clock in the Power
Management Controller (PMC).
38.6.2 PWM Channel
38.6.2.1 Block Diagram
Figure 38-3. Functional View of the Channel Block Diagram
Each of the 8 channels is composed of six blocks:
A clock selector which selects one of the clocks provided by the clock generator (described in Section 38.6.1
on page 976).
A counter clocked by the output of the clock selector. This counter is incremented or decremented according
to the channel configuration and comparators matches. The size of the counter is 16 bits.
A comparator used to compute the OCx output waveform according to the counter value and the
configuration. The counter value can be the one of the channel counter or the one of the channel 0 counter
according to SYNCx bit in the “PWM Sync Channels Mode Register” on page 1014 (PWM_SCM).
A 2-bit configurable gray counter enables the stepper motor driver. One gray counter drives 2 channels.
A dead-time generator providing two complementary outputs (DTOHx/DTOLx) which allows to drive external
power control switches safely.
An output override block that can force the two complementary outputs to a programmed value
(OOOHx/OOOLx).
An asynchronous fault protection mechanism that has the highest priority to override the two complementary
outputs in case of fault detection (PWMHx/PWMLx).
Comparator
x
Cl o ck
Se l e c t o r
Channel x
Dead-Time
Gen er at o r
Out p ut
Overri de
OCx
DTOHx
DTOLx
Fau l t
Protection
OOOHx PWM Hx
PWMLx
OOOLx
Counter
Channel x
Dut y-Cycle
Pe r i o d
Upd at e
Co u n t e r
Channel 0
MUX SYNCx
Dead-Time
Gen er at o r
Out p ut
Overri de
OCy DTOHy
DTOLy
Fau l t
Protection
OOOHy PWMHy
PWMLy
OOOLy
Channel y (= x+1)
MUX MUX
2-bit gray
counter z
Comparator
y
from
Clock
Generator
from APB
Peripheral Bus
z = 0 (x = 0, y = 1),
z = 1 (x = 2, y = 3),
z = 2 (x = 4, y = 5),
z = 3 (x = 6, y = 7)
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38.6.2.2 Comparator
The comparator continuously compares its counter value with the channel period defined by CPRD in the “PWM
Channel Period Register” on page 1048 (PWM_CPRDx) and the duty-cycle defined by CDTY in the “PWM
Channel Duty Cycle Register” on page 1046 (PWM_CDTYx) to generate an output signal OCx accordingly.
The different properties of the waveform of the output OCx are:
the clock selection. The channel counter is clocked by one of the clocks provided by the clock generator
described in the previous section. This channel parameter is defined in the CPRE field of the “PWM Channel
Mode Register” on page 1044 (PWM_CMRx). This field is reset at 0.
the waveform period. This channel parameter is defined in the CPRD field of the PWM_CPRDx register.
If the waveform is left aligned, then the output waveform period depends on the counter source clock and
can be calculated:
By using the PWM master clock (MCK) divided by an X given prescaler value (with X being 1, 2, 4, 8, 16, 32,
64, 128, 256, 512, or 1024), the resulting period formula will be:
By using the PWM master clock (MCK) divided by one of both DIVA or DIVB divider, the formula becomes,
respectively:
or
If the waveform is center aligned then the output waveform period depends on the counter source clock and
can be calculated:
By using the PWM master clock (MCK) divided by an X given prescaler value
(with X being 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024). The resulting period formula will be:
By using the PWM master clock (MCK) divided by one of both DIVA or DIVB divider, the formula becomes,
respectively:
or
the waveform duty-cycle. This channel parameter is defined in the CDTY field of the PWM_CDTYx
register.
If the waveform is left aligned then:
If the waveform is center aligned, then:
the waveform polarity. At the beginning of the period, the signal can be at high or low level. This property is
defined in the CPOL field of the PWM_CMRx register. By default the signal starts by a low level.
XCPRD×()
MCK
-------------------------------
CRPD DIVA×()
MCK
------------------------------------------
CRPD DIVB×()
MCK
------------------------------------------
2XCPRD××()
MCK
----------------------------------------
2CPRD DIVA××()
MCK
---------------------------------------------------
2CPRD×DIVB×()
MCK
---------------------------------------------------
duty cycle period 1 fchannel_x_clock CDTY×⁄–()
period
----------------------------------------------------------------------------------------------------
=
duty cycle period 2⁄()1 fchannel_x_clock CDTY×⁄–())
period 2⁄()
-------------------------------------------------------------------------------------------------------------------
=
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the waveform alignment. The output waveform can be left or center aligned. Center aligned waveforms can
be used to generate non overlapped waveforms. This property is defined in the CALG field of the
PWM_CMRx register. The default mode is left aligned.
Figure 38-4. Non Overlapped Center Aligned Waveforms
Note: 1. See Figure 38-5 on page 980 for a detailed description of center aligned waveforms.
When center aligned, the channel counter increases up to CPRD and decreases down to 0. This ends the period.
When left aligned, the channel counter increases up to CPRD and is reset. This ends the period.
Thus, for the same CPRD value, the period for a center aligned channel is twice the period for a left aligned
channel.
Waveforms are fixed at 0 when:
CDTY = CPRD and CPOL = 0
CDTY = 0 and CPOL = 1
Waveforms are fixed at 1 (once the channel is enabled) when:
CDTY = 0 and CPOL = 0
CDTY = CPRD and CPOL = 1
The waveform polarity must be set before enabling the channel. This immediately affects the channel output level.
Changes on channel polarity are not taken into account while the channel is enabled.
Besides generating output signals OCx, the comparator generates interrupts in function of the counter value.
When the output waveform is left aligned, the interrupt occurs at the end of the counter period. When the output
waveform is center aligned, the bit CES of the PWM_CMRx register defines when the channel counter interrupt
occurs. If CES is set to 0, the interrupt occurs at the end of the counter period. If CES is set to 1, the interrupt
occurs at the end of the counter period and at half of the counter period.
Figure 38-5 “Waveform Properties” illustrates the counter interrupts in function of the configuration.
OC0
OC1
Period
No overlap
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Figure 38-5. Waveform Properties
Channel x
slected clock
CHIDx(PWM_SR)
Center Aligned
CPRD(PWM_CPRDx)
CDTY(PWM_CDTYx)
PWM_CCNTx
Output Waveform OCx
CPOL(PWM_CMRx) = 0
Output Waveform OCx
CPOL(PWM_CMRx) = 1
Counter Event
CHIDx(PWM_ISR)
CES(PWM_CMRx) = 0
Left Aligned
CPRD(PWM_CPRDx)
CDTY(PWM_CDTYx)
PWM_CCNTx
Output Waveform OCx
CPOL(PWM_CMRx) = 0
Output Waveform OCx
CPOL(PWM_CMRx) = 1
CALG(PWM_CMRx) = 0
CALG(PWM_CMRx) = 1
Period
Period
CHIDx(PWM_ENA)
CHIDx(PWM_DIS)
Counter Event
CHIDx(PWM_ISR)
CES(PWM_CMRx) = 1
Counter Event
CHIDx(PWM_ISR)
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38.6.2.3 2-bit Gray Up/Down Counter for Stepper Motor
It is possible to configure a couple of channels to provide a 2-bit gray count waveform on 2 outputs. Dead-Time
Generator and other downstream logic can be configured on these channels.
Up or down count mode can be configured on-the-fly by means of PWM_SMMR configuration registers.
When GCEN0 is set to 1, channels 0 and 1 outputs are driven with gray counter.
Figure 38-6. 2-bit Gray Up/Down Counter
38.6.2.4 Dead-Time Generator
The dead-time generator uses the comparator output OCx to provide the two complementary outputs DTOHx and
DTOLx, which allows the PWM macrocell to drive external power control switches safely. When the dead-time
generator is enabled by setting the bit DTE to 1 or 0 in the “PWM Channel Mode Register” (PWM_CMRx), dead-
times (also called dead-bands or non-overlapping times) are inserted between the edges of the two
complementary outputs DTOHx and DTOLx. Note that enabling or disabling the dead-time generator is allowed
only if the channel is disabled.
The dead-time is adjustable by the “PWM Channel Dead Time Register” (PWM_DTx). Both outputs of the dead-
time generator can be adjusted separately by DTH and DTL. The dead-time values can be updated synchronously
to the PWM period by using the “PWM Channel Dead Time Update Register” (PWM_DTUPDx).
The dead-time is based on a specific counter which uses the same selected clock that feeds the channel counter
of the comparator. Depending on the edge and the configuration of the dead-time, DTOHx and DTOLx are delayed
until the counter has reached the value defined by DTH or DTL. An inverted configuration bit (DTHI and DTLI bit in
the PWM_CMRx register) is provided for each output to invert the dead-time outputs. The following figure shows
the waveform of the dead-time generator.
PWMH0
DOWNx
GCEN0 = 1
PWMH1
PWML0
PWML1
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Figure 38-7. Complementary Output Waveforms
38.6.2.5 Output Override
The two complementary outputs DTOHx and DTOLx of the dead-time generator can be forced to a value defined
by the software.
Figure 38-8. Override Output Selection
The fields OSHx and OSLx in the “PWM Output Selection Register” (PWM_OS) allow the outputs of the dead-time
generator DTOHx and DTOLx to be overridden by the value defined in the fields OOVHx and OOVLx in the“PWM
Output Override Value Register” (PWM_OOV).
The set registers “PWM Output Selection Set Register” and “PWM Output Selection Set Update Register”
(PWM_OSS and PWM_OSSUPD) enable the override of the outputs of a channel regardless of other channels. In
the same way, the clear registers “PWM Output Selection Clear Register” and “PWM Output Selection Clear
Update Register” (PWM_OSC and PWM_OSCUPD) disable the override of the outputs of a channel regardless of
other channels.
DTHx DTLx
output waveform OCx
CPOLx = 0
output waveform DTOHx
DTHIx = 0
output waveform DTOLx
DTLIx = 0
output waveform DTOHx
DTHIx = 1
output waveform DTOLx
DTLIx = 1
DTHx DTLx
output waveform OCx
CPOLx = 1
output waveform DTOHx
DTHIx = 0
output waveform DTOLx
DTLIx = 0
output waveform DTOHx
DTHIx = 1
output waveform DTOLx
DTLIx = 1
DTOHx
OOVHx
OOOHx
OSHx
0
1
DTOLx
OOVLx
OOOLx
OSLx
0
1
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By using buffer registers PWM_OSSUPD and PWM_OSCUPD, the output selection of PWM outputs is done
synchronously to the channel counter, at the beginning of the next PWM period.
By using registers PWM_OSS and PWM_OSC, the output selection of PWM outputs is done asynchronously to
the channel counter, as soon as the register is written.
The value of the current output selection can be read in PWM_OS.
While overriding PWM outputs, the channel counters continue to run, only the PWM outputs are forced to user
defined values.
38.6.2.6 Fault Protection
6 inputs provide fault protection which can force any of the PWM output pair to a programmable value. This
mechanism has priority over output overriding.
Figure 38-9. Fault Protection
The polarity level of the fault inputs is configured by the FPOL field in the “PWM Fault Mode Register”
(PWM_FMR). For fault inputs coming from internal peripherals such as ADC, Timer Counter, to name but a few,
the polarity level must be FPOL = 1. For fault inputs coming from external GPIO pins the polarity level depends on
the user's implementation.
The configuration of the Fault Activation Mode (FMOD bit in PWMC_FMR) depends on the peripheral generating
the fault. If the corresponding peripheral does not have “Fault Clear” management, then the FMOD configuration to
use must be FMOD = 1, to avoid spurious fault detection. Check the corresponding peripheral documentation for
details on handling fault generation.
The fault inputs can be glitch filtered or not in function of the FFIL field in the PWM_FMR register. When the filter is
activated, glitches on fault inputs with a width inferior to the PWM master clock (MCK) period are rejected.
A fault becomes active as soon as its corresponding fault input has a transition to the programmed polarity level. If
the corresponding bit FMOD is set to 0 in the PWM_FMR register, the fault remains active as long as the fault input
is at this polarity level. If the corresponding FMOD bit is set to 1, the fault remains active until the fault input is not
at this polarity level anymore and until it is cleared by writing the corresponding bit FCLR in the “PWM Fault Clear
Register” (PWM_FSCR). By reading the “PWM Fault Status Register” (PWM_FSR), the user can read the current
level of the fault inputs by means of the field FIV, and can know which fault is currently active thanks to the FS field.
Each fault can be taken into account or not by the fault protection mechanism in each channel. To be taken into
account in the channel x, the fault y must be enabled by the bit FPEx[y] in the “PWM Fault Protection Enable
Registers” (PWM_FPE1/2). However the synchronous channels (see Section 38.6.2.7 “Synchronous Channels”)
do not use their own fault enable bits, but those of the channel 0 (bits FPE0[y]).
FIV0
fault input 0
Fault protection
on PWM
channel x
Glitch
Filter
FFIL0
from fault 0
from fault y
1
0=
FPOL0 FMOD0
1
0Fault 0 Status
FS0
FIV1
Glitch
Filter
FFIL1
1
0=
FPOL1
SET
CLR
FMOD1
1
0
OUT
Fault 1 Status
FS1
fault input 1 from fault 1 1
0
0
1
From Output
Override
OOHx
OOLx
From Output
Override
FPVHx
FPVLx
PWMHx
PWMLx
fault input y
FMOD1
SET
CLR
Write FCLR0 at 1
OUT
FMOD0
Write FCLR1 at 1
SYNCx
1
0
FPEx[0]
FPE0[0]
SYNCx
1
0
FPEx[1]
FPE0[1]
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The fault protection on a channel is triggered when this channel is enabled and when any one of the faults that are
enabled for this channel is active. It can be triggered even if the PWM master clock (MCK) is not running but only
by a fault input that is not glitch filtered.
When the fault protection is triggered on a channel, the fault protection mechanism forces the channel outputs to
the values defined by the fields FPVHx and FPVLx in the “PWM Fault Protection Value Register” (PWM_FPV) and
leads to a reset of the counter of this channel. The output forcing is made asynchronously to the channel counter.
CAUTION:
To prevent an unexpected activation of the status flag FSy in the PWM_FSR register, the FMODy bit can be
set to “1” only if the FPOLy bit has been previously configured to its final value.
To prevent an unexpected activation of the Fault Protection on the channel x, the bit FPEx[y] can be set to
“1” only if the FPOLy bit has been previously configured to its final value.
If a comparison unit is enabled (see Section 38.6.3 “PWM Comparison Units”) and if a fault is triggered in the
channel 0, in this case the comparison cannot match.
As soon as the fault protection is triggered on a channel, an interrupt (different from the interrupt generated at the
end of the PWM period) can be generated but only if it is enabled and not masked. The interrupt is reset by reading
the interrupt status register, even if the fault which has caused the trigger of the fault protection is kept active.
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38.6.2.7 Synchronous Channels
Some channels can be linked together as synchronous channels. They have the same source clock, the same
period, the same alignment and are started together. In this way, their counters are synchronized together.
The synchronous channels are defined by the SYNCx bits in the “PWM Sync Channels Mode Register”
(PWM_SCM). Only one group of synchronous channels is allowed.
When a channel is defined as a synchronous channel, the channel 0 is automatically defined as a synchronous
channel too, because the channel 0 counter configuration is used by all the synchronous channels.
If a channel x is defined as a synchronous channel, it uses the following configuration fields of the channel 0
instead of its own:
CPRE0 field in PWM_CMR0 register instead of CPREx field in PWM_CMRx register (same source clock)
CPRD0 field in PWM_CMR0 register instead of CPRDx field in PWM_CMRx register (same period)
CALG0 field in PWM_CMR0 register instead of CALGx field in PWM_CMRx register (same alignment)
Thus writing these fields of a synchronous channel has no effect on the output waveform of this channel (except
channel 0 of course).
Because counters of synchronous channels must start at the same time, they are all enabled together by enabling
the channel 0 (by the CHID0 bit in PWM_ENA register). In the same way, they are all disabled together by
disabling channel 0 (by the CHID0 bit in PWM_DIS register). However, a synchronous channel x different from
channel 0 can be enabled or disabled independently from others (by the CHIDx bit in PWM_ENA and PWM_DIS
registers).
Defining a channel as a synchronous channel while it is an asynchronous channel (by writing the bit SYNCx to 1
while it was at 0) is allowed only if the channel is disabled at this time (CHIDx = 0 in PWM_SR register). In the same
way, defining a channel as an asynchronous channel while it is a synchronous channel (by writing the SYNCx bit
to 0 while it was 1) is allowed only if the channel is disabled at this time.
The field UPDM (Update Mode) in the PWM_SCM register allow to select one of the three methods to update the
registers of the synchronous channels:
Method 1 (UPDM = 0): the period value, the duty-cycle values and the dead-time values must be written by
the CPU in their respective update registers (respectively PWM_CPRDUPDx, PWM_CDTYUPDx and
PWM_DTUPDx).The update is triggered at the next PWM period as soon as the bit UPDULOCK in the
“PWM Sync Channels Update Control Register” (PWM_SCUC) is set to 1 (see “Method 1: Manual write of
duty-cycle values and manual trigger of the update” on page 987).
Method 2 (UPDM = 1): the period value, the duty-cycle values, the dead-time values and the update period
value must be written by the CPU in their respective update registers (respectively PWM_CPRDUPDx,
PWM_CDTYUPDx and PWM_DTUPD). The update of the period value and of the dead-time values is
triggered at the next PWM period as soon as the bit UPDULOCK in the “PWM Sync Channels Update
Control Register” (PWM_SCUC) is set to 1. The update of the duty-cycle values and the update period
value is triggered automatically after an update period defined by the field UPR in the “PWM Sync Channels
Update Period Register” (PWM_SCUP) (see “Method 2: Manual write of duty-cycle values and automatic
trigger of the update” on page 988).
Method 3 (UPDM = 2): same as Method 2 apart from the fact that the duty-cycle values of ALL synchronous
channels are written by the Peripheral DMA Controller (PDC) (see “Method 3: Automatic write of duty-cycle
values and automatic trigger of the update” on page 990). The user can choose to synchronize the PDC
transfer request with a comparison match (see Section 38.6.3 “PWM Comparison Units”), by the fields
PTRM and PTRCS in the PWM_SCM register.
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Table 38-5. Summary of the Update of Registers of Synchronous Channels
UPDM=0 UPDM=1 UPDM=2
Period Value
(PWM_CPRDUPDx)
Write by the CPU
Update is triggered at the
next PWM period as soon as
the bit UPDULOCK is set to 1
Dead-Time Values
(PWM_DTUPDx)
Write by the CPU
Update is triggered at the
next PWM period as soon as
the bit UPDULOCK is set to 1
Duty-Cycle Values
(PWM_CDTYUPDx)
Write by the CPU Write by the CPU Write by the PDC
Update is triggered at the next
PWM period as soon as the bit
UPDULOCK is set to 1
Update is triggered at the next
PWM period as soon as the update period
counter has reached the value UPR
Update Period Value
(PWM_SCUPUPD)
Not applicable Write by the CPU
Not applicable
Update is triggered at the next
PWM period as soon as the update period
counter has reached the value UPR
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Method 1: Manual write of duty-cycle values and manual trigger of the update
In this mode, the update of the period value, the duty-cycle values and the dead-time values must be done by
writing in their respective update registers with the CPU (respectively PWM_CPRDUPDx, PWM_CDTYUPDx and
PWM_DTUPDx).
To trigger the update, the user must use the bit UPDULOCK of the “PWM Sync Channels Update Control
Register” (PWM_SCUC) which allows to update synchronously (at the same PWM period) the synchronous
channels:
If the bit UPDULOCK is set to 1, the update is done at the next PWM period of the synchronous channels.
If the UPDULOCK bit is not set to 1, the update is locked and cannot be performed.
After writing the UPDULOCK bit to 1, it is held at this value until the update occurs, then it is read 0.
Sequence for Method 1:
1. Select the manual write of duty-cycle values and the manual update by setting the UPDM field to 0 in the
PWM_SCM register
2. Define the synchronous channels by the SYNCx bits in the PWM_SCM register.
3. Enable the synchronous channels by writing CHID0 in the PWM_ENA register.
4. If an update of the period value and/or the duty-cycle values and/or the dead-time values is required, write
registers that need to be updated (PWM_CPRDUPDx, PWM_CDTYUPDx and PWM_DTUPDx).
5. Set UPDULOCK to 1 in PWM_SCUC.
6. The update of the registers will occur at the beginning of the next PWM period. At this moment the
UPDULOCK bit is reset, go to Step 4.) for new values.
Figure 38-10. Method 1 (UPDM = 0)
CCNT0
CDTYUPD 0x20 0x40 0x60
UPDULOCK
CDTY 0x20 0x40 0x60
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Method 2: Manual write of duty-cycle values and automatic trigger of the update
In this mode, the update of the period value, the duty-cycle values, the dead-time values and the update period
value must be done by writing in their respective update registers with the CPU (respectively PWM_CPRDUPDx,
PWM_CDTYUPDx, PWM_DTUPDx and PWM_SCUPUPD).
To trigger the update of the period value and the dead-time values, the user must use the bit UPDULOCK of the
“PWM Sync Channels Update Control Register” (PWM_SCUC) which allows to update synchronously (at the
same PWM period) the synchronous channels:
If the bit UPDULOCK is set to 1, the update is done at the next PWM period of the synchronous channels.
If the UPDULOCK bit is not set to 1, the update is locked and cannot be performed.
After writing the UPDULOCK bit to 1, it is held at this value until the update occurs, then it is read 0.
The update of the duty-cycle values and the update period is triggered automatically after an update period.
To configure the automatic update, the user must define a value for the Update Period by the UPR field in the
“PWM Sync Channels Update Period Register” (PWM_SCUP). The PWM controller waits UPR+1 period of
synchronous channels before updating automatically the duty values and the update period value.
The status of the duty-cycle value write is reported in the “PWM Interrupt Status Register 2” (PWM_ISR2) by the
following flags:
WRDY: this flag is set to 1 when the PWM Controller is ready to receive new duty-cycle values and a new
update period value. It is reset to 0 when the PWM_ISR2 register is read.
Depending on the interrupt mask in the PWM_IMR2 register, an interrupt can be generated by these flags.
Sequence for Method 2:
1. Select the manual write of duty-cycle values and the automatic update by setting the field UPDM to 1 in
the PWM_SCM register
2. Define the synchronous channels by the bits SYNCx in the PWM_SCM register.
3. Define the update period by the field UPR in the PWM_SCUP register.
4. Enable the synchronous channels by writing CHID0 in the PWM_ENA register.
5. If an update of the period value and/or of the dead-time values is required, write registers that need to be
updated (PWM_CPRDUPDx, PWM_DTUPDx), else go to Step 8.
6. Set UPDULOCK to 1 in PWM_SCUC.
7. The update of these registers will occur at the beginning of the next PWM period. At this moment the bit
UPDULOCK is reset, go to Step 5. for new values.
8. If an update of the duty-cycle values and/or the update period is required, check first that write of new update
values is possible by polling the flag WRDY (or by waiting for the corresponding interrupt) in the PWM_ISR2
register.
9. Write registers that need to be updated (PWM_CDTYUPDx, PWM_SCUPUPD).
10. The update of these registers will occur at the next PWM period of the synchronous channels when the
Update Period is elapsed. Go to Step 8. for new values.
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Figure 38-11. Method 2 (UPDM=1)
CCNT0
CDTYUPD 0x20 0x40 0x60
UPRCNT 0x0 0x1 0x0 0x1 0x0 0x1
CDTY 0x20 0x40
UPRUPD 0x1 0x3
WRDY
0x60
0x0 0x1 0x2 0x3 0x0 0x1 0x2
UPR 0x1 0x3
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Method 3: Automatic write of duty-cycle values and automatic trigger of the update
In this mode, the update of the duty cycle values is made automatically by the Peripheral DMA Controller (PDC).
The update of the period value, the dead-time values and the update period value must be done by writing in their
respective update registers with the CPU (respectively PWM_CPRDUPDx, PWM_DTUPDx and
PWM_SCUPUPD).
To trigger the update of the period value and the dead-time values, the user must use the bit UPDULOCK which
allows to update synchronously (at the same PWM period) the synchronous channels:
If the bit UPDULOCK is set to 1, the update is done at the next PWM period of the synchronous channels.
If the UPDULOCK bit is not set to 1, the update is locked and cannot be performed.
After writing the UPDULOCK bit to 1, it is held at this value until the update occurs, then it is read 0.
The update of the duty-cycle values and the update period value is triggered automatically after an update period.
To configure the automatic update, the user must define a value for the Update Period by the field UPR in the
“PWM Sync Channels Update Period Register” (PWM_SCUP). The PWM controller waits UPR+1 periods of
synchronous channels before updating automatically the duty values and the update period value.
Using the PDC removes processor overhead by reducing its intervention during the transfer. This significantly
reduces the number of clock cycles required for a data transfer, which improves microcontroller performance.
The PDC must write the duty-cycle values in the synchronous channels index order. For example if the channels 0,
1 and 3 are synchronous channels, the PDC must write the duty-cycle of the channel 0 first, then the duty-cycle of
the channel 1, and finally the duty-cycle of the channel 3.
The status of the PDC transfer is reported in the “PWM Interrupt Status Register 2” (PWM_ISR2) by the following
flags:
WRDY: this flag is set to 1 when the PWM Controller is ready to receive new duty-cycle values and a new
update period value. It is reset to 0 when the PWM_ISR2 register is read. The user can choose to
synchronize the WRDY flag and the PDC transfer request with a comparison match (see Section 38.6.3
“PWM Comparison Units”), by the fields PTRM and PTRCS in the PWM_SCM register.
ENDTX: this flag is set to 1 when a PDC transfer is completed
TXBUFE: this flag is set to 1 when the PDC buffer is empty (no pending PDC transfers)
UNRE: this flag is set to 1 when the update period defined by the UPR field has elapsed while the whole data
has not been written by the PDC. It is reset to 0 when the PWM_ISR2 register is read.
Depending on the interrupt mask in the PWM_IMR2 register, an interrupt can be generated by these flags.
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Sequence for Method 3:
1. Select the automatic write of duty-cycle values and automatic update by setting the field UPDM to 2 in the
PWM_SCM register.
2. Define the synchronous channels by the bits SYNCx in the PWM_SCM register.
3. Define the update period by the field UPR in the PWM_SCUP register.
4. Define when the WRDY flag and the corresponding PDC transfer request must be set in the update period
by the PTRM bit and the PTRCS field in the PWM_SCM register (at the end of the update period or when a
comparison matches).
5. Define the PDC transfer settings for the duty-cycle values and enable it in the PDC registers
6. Enable the synchronous channels by writing CHID0 in the PWM_ENA register.
7. If an update of the period value and/or of the dead-time values is required, write registers that need to be
updated (PWM_CPRDUPDx, PWM_DTUPDx), else go to Step 10.
8. Set UPDULOCK to 1 in PWM_SCUC.
9. The update of these registers will occur at the beginning of the next PWM period. At this moment the bit
UPDULOCK is reset, go to Step 7. for new values.
10. If an update of the update period value is required, check first that write of a new update value is possible by
polling the flag WRDY (or by waiting for the corresponding interrupt) in the PWM_ISR2 register, else go to
Step 13.
11. Write the register that needs to be updated (PWM_SCUPUPD).
12. The update of this register will occur at the next PWM period of the synchronous channels when the Update
Period is elapsed. Go to Step 10. for new values.
13. Check the end of the PDC transfer by the flag ENDTX. If the transfer has ended, define a new PDC transfer
in the PDC registers for new duty-cycle values. Go to Step 5.
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Figure 38-12. Method 3 (UPDM=2 and PTRM=0)
Figure 38-13. Method 3 (UPDM=2 and PTRM=1 and PTRCS=0)
CCNT0
CDTYUPD 0x20 0x40 0x60
UPRCNT 0x0 0x1 0x0 0x1 0x0 0x1
CDTY
UPRUPD 0x1 0x3
PDC transfer request
WRDY
0x0 0x1 0x2 0x3 0x0 0x1 0x2
UPR 0x1 0x3
0x80 0xA0 0xB0
0x20 0x40 0x60 0x80 0xA0
CCNT0
CDTYUPD 0x20 0x40 0x60
UPRCNT 0x0 0x1 0x0 0x1 0x0 0x1
CDTY
UPRUPD 0x1 0x3
CMP0 match
PDC transfer request
WRDY
0x0 0x1 0x2 0x3 0x0 0x1 0x2
UPR 0x1 0x3
0x80 0xA0 0xB0
0x20 0x40 0x60 0x80 0xA0
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38.6.3 PWM Comparison Units
The PWM provides 8 independent comparison units able to compare a programmed value with the current value of
the channel 0 counter (which is the channel counter of all synchronous channels, Section 38.6.2.7 “Synchronous
Channels”). These comparisons are intended to generate pulses on the event lines (used to synchronize ADC, see
Section 38.6.4 “PWM Event Lines”), to generate software interrupts and to trigger PDC transfer requests for the
synchronous channels (see “Method 3: Automatic write of duty-cycle values and automatic trigger of the update”
on page 990).
Figure 38-14. Comparison Unit Block Diagram
The comparison x matches when it is enabled by the bit CEN in the “PWM Comparison x Mode Register”
(PWM_CMPMx for the comparison x) and when the counter of the channel 0 reaches the comparison value
defined by the field CV in “PWM Comparison x Value Register” (PWM_CMPVx for the comparison x). If the
counter of the channel 0 is center aligned (CALG = 1 in “PWM Channel Mode Register” ), the bit CVM (in
PWM_CMPVx) defines if the comparison is made when the counter is counting up or counting down (in left
alignment mode CALG=0, this bit is useless).
If a fault is active on the channel 0, the comparison is disabled and cannot match (see Section 38.6.2.6 “Fault
Protection”).
The user can define the periodicity of the comparison x by the fields CTR and CPR (in PWM_CMPVx). The
comparison is performed periodically once every CPR+1 periods of the counter of the channel 0, when the value of
the comparison period counter CPRCNT (in PWM_CMPMx) reaches the value defined by CTR. CPR is the
maximum value of the comparison period counter CPRCNT. If CPR=CTR=0, the comparison is performed at each
period of the counter of the channel 0.
The comparison x configuration can be modified while the channel 0 is enabled by using the “PWM Comparison x
Mode Update Register” (PWM_CMPMUPDx registers for the comparison x). In the same way, the comparison x
value can be modified while the channel 0 is enabled by using the “PWM Comparison x Value Update Register”
(PWM_CMPVUPDx registers for the comparison x).
The update of the comparison x configuration and the comparison x value is triggered periodically after the
comparison x update period. It is defined by the field CUPR in the PWM_CMPMx. The comparison unit has an
update period counter independent from the period counter to trigger this update. When the value of the
comparison update period counter CUPRCNT (in PWM_CMPMx) reaches the value defined by CUPR, the update
=
Fault on channel 0
CNT [PWM_CCNT0]
CNT [PWM_CCNT0] is decrementing
CALG [PWM_CMR0]
CV [PWM_CMPVx]
=1
0
1
Comparison x
CVM [PWM_CMPVx]
=
CPRCNT [PWM_CMPMx]
CTR [PWM_CMPMx]
CEN [PWM_CMPM]x
CAUTION: Xlx x X XX XXX Xle X X X X X X X? XX‘X X
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is triggered. The comparison x update period CUPR itself can be updated while the channel 0 is enabled by using
the PWM_CMPMUPDx register.
CAUTION: to be taken into account, the write of the register PWM_CMPVUPDx must be followed by a write of the
register PWM_CMPMUPDx.
The comparison match and the comparison update can be source of an interrupt, but only if it is enabled and not
masked. These interrupts can be enabled by the “PWM Interrupt Enable Register 2” and disabled by the “PWM
Interrupt Disable Register 2” . The comparison match interrupt and the comparison update interrupt are reset by
reading the “PWM Interrupt Status Register 2”
Figure 38-15. Comparison Waveform
CCNT0
CVUPD
0x6 0x2
CVMVUPD
CV
0x6 0x2
0x6
0x6
CVM
Comparison Update
CMPU
CTRUPD
0x1 0x2
CPR
0x1 0x3
0x0 0x1 0x0 0x1 0x0 0x1 0x2 0x3 0x0 0x1 0x2 0x3
CPRCNT
0x0 0x1 0x2 0x3 0x0 0x1 0x2
0x0
0x1 0x2 0x0 0x1
CUPRCNT
CPRUPD
0x1 0x3
CUPRUPD
0x3 0x2
CTR
0x1 0x2
CUPR
0x3 0x2
Comparison Match
CMPM
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38.6.4 PWM Event Lines
The PWM provides 2 independent event lines intended to trigger actions in other peripherals (in particular for ADC
(Analog-to-Digital Converter)).
A pulse (one cycle of the master clock (MCK)) is generated on an event line, when at least one of the selected
comparisons is matching. The comparisons can be selected or unselected independently by the CSEL bits in the
“PWM Event Line x Register” (PWM_ELMRx for the Event Line x).
Figure 38-16. Event Line Block Diagram
PULSE
GENERATOR
Event Line x
CSEL0 (PWM_ELMRx)
CMPS0 (PWM_ISR2)
CSEL1 (PWM_ELMRx)
CMPS1 (PWM_ISR2)
CSEL2 (PWM_ELMRx)
CMPS2 (PWM_ISR2)
CSEL7 (PWM_ELMRx)
CMPS7 (PWM_ISR2)
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38.6.5 PWM Controller Operations
38.6.5.1 Initialization
Before enabling the channels, they must have been configured by the software application:
Unlock User Interface by writing the WPCMD field in the PWM_WPCR Register.
Configuration of the clock generator (DIVA, PREA, DIVB, PREB in the PWM_CLK register if required).
Selection of the clock for each channel (CPRE field in the PWM_CMRx register)
Configuration of the waveform alignment for each channel (CALG field in the PWM_CMRx register)
Selection of the counter event selection (if CALG = 1) for each channel (CES field in the PWM_CMRx
register)
Configuration of the output waveform polarity for each channel (CPOL in the PWM_CMRx register)
Configuration of the period for each channel (CPRD in the PWM_CPRDx register). Writing in PWM_CPRDx
register is possible while the channel is disabled. After validation of the channel, the user must use
PWM_CPRDUPDx register to update PWM_CPRDx as explained below.
Configuration of the duty-cycle for each channel (CDTY in the PWM_CDTYx register). Writing in
PWM_CDTYx register is possible while the channel is disabled. After validation of the channel, the user
must use PWM_CDTYUPDx register to update PWM_CDTYx as explained below.
Configuration of the dead-time generator for each channel (DTH and DTL in PWM_DTx) if enabled (DTE bit
in the PWM_CMRx register). Writing in the PWM_DTx register is possible while the channel is disabled.
After validation of the channel, the user must use PWM_DTUPDx register to update PWM_DTx
Selection of the synchronous channels (SYNCx in the PWM_SCM register)
Selection of the moment when the WRDY flag and the corresponding PDC transfer request are set (PTRM
and PTRCS in the PWM_SCM register)
Configuration of the update mode (UPDM in the PWM_SCM register)
Configuration of the update period (UPR in the PWM_SCUP register) if needed.
Configuration of the comparisons (PWM_CMPVx and PWM_CMPMx).
Configuration of the event lines (PWM_ELMRx).
Configuration of the fault inputs polarity (FPOL in PWM_FMR)
Configuration of the fault protection (FMOD and FFIL in PWM_FMR, PWM_FPV and PWM_FPE/2)
Enable of the Interrupts (writing CHIDx and FCHIDx in PWM_IER1 register, and writing WRDYE, ENDTXE,
TXBUFE, UNRE, CMPMx and CMPUx in PWM_IER2 register)
Enable of the PWM channels (writing CHIDx in the PWM_ENA register)
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38.6.5.2 Source Clock Selection Criteria
The large number of source clocks can make selection difficult. The relationship between the value in the “PWM
Channel Period Register” (PWM_CPRDx) and the “PWM Channel Duty Cycle Register” (PWM_CDTYx) can help
the user in choosing. The event number written in the Period Register gives the PWM accuracy. The Duty-Cycle
quantum cannot be lower than 1/CPRDx value. The higher the value of PWM_CPRDx, the greater the PWM
accuracy.
For example, if the user sets 15 (in decimal) in PWM_CPRDx, the user is able to set a value from between 1 up to
14 in PWM_CDTYx Register. The resulting duty-cycle quantum cannot be lower than 1/15 of the PWM period.
38.6.5.3 Changing the Duty-Cycle, the Period and the Dead-Times
It is possible to modulate the output waveform duty-cycle, period and dead-times.
To prevent unexpected output waveform, the user must use the “PWM Channel Duty Cycle Update Register” , the
“PWM Channel Period Update Register” and the “PWM Channel Dead Time Update Register”
(PWM_CDTYUPDx, PWM_CPRDUPDx and PWM_DTUPDx) to change waveform parameters while the channel
is still enabled.
If the channel is an asynchronous channel (SYNCx = 0 in “PWM Sync Channels Mode Register”
(PWM_SCM)), these registers hold the new period, duty-cycle and dead-times values until the end of the
current PWM period and update the values for the next period.
If the channel is a synchronous channel and update method 0 is selected (SYNCx = 1 and UPDM = 0 in
PWM_SCM register), these registers hold the new period, duty-cycle and dead-times values until the bit
UPDULOCK is written at “1” (in “PWM Sync Channels Update Control Register” (PWM_SCUC)) and the
end of the current PWM period, then update the values for the next period.
If the channel is a synchronous channel and update method 1 or 2 is selected (SYNCx=1 and UPDM=1 or 2
in PWM_SCM register):
̶registers PWM_CPRDUPDx and PWM_DTUPDx hold the new period and dead-times values until the
bit UPDULOCK is written at “1” (in PWM_SCUC register) and the end of the current PWM period, then
update the values for the next period.
̶register PWM_CDTYUPDx holds the new duty-cycle value until the end of the update period of
synchronous channels (when UPRCNT is equal to UPR in “PWM Sync Channels Update Period
Register” (PWM_SCUP)) and the end of the current PWM period, then updates the value for the next
period
Note: If the update registers PWM_CDTYUPDx, PWM_CPRDUPDx and PWM_DTUPDx are written several times between
two updates, only the last written value is taken into account.
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Figure 38-17. Synchronized Period, Duty-Cycle and Dead-Times Update
PWM_CPRDUPDx Value
PWM_CPRDx PWM_CDTYx
- If Asynchronous Channel
-> End of PWM period
- If Synchronous Channel
-> End of PWM period and UPDULOCK = 1
User'sWriting
PWM_DTUPDx Value
User'sWriting
PWM_DTx
- If Asynchronous Channel
-> End of PWM period
- If Synchronous Channel
- If UPDM = 0
-> End of PWM period and UPDULOCK = 1
- If UPDM = 1 or 2
-> End of PWM period and end of Update Period
PWM_CDTYUPDx Value
User'sWriting
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38.6.5.4 Changing the Synchronous Channels Update Period
It is possible to change the update period of synchronous channels while they are enabled. (See “Method 2:
Manual write of duty-cycle values and automatic trigger of the update” on page 988 and “Method 3: Automatic
write of duty-cycle values and automatic trigger of the update” on page 990.)
To prevent an unexpected update of the synchronous channels registers, the user must use the “PWM Sync
Channels Update Period Update Register” (PWM_SCUPUPD) to change the update period of synchronous
channels while they are still enabled. This register holds the new value until the end of the update period of
synchronous channels (when UPRCNT is equal to UPR in “PWM Sync Channels Update Period Register”
(PWM_SCUP)) and the end of the current PWM period, then updates the value for the next period.
Note: If the update register PWM_SCUPUPD is written several times between two updates, only the last written value is
taken into account.
Note: Changing the update period does make sense only if there is one or more synchronous channels and if the update
method 1 or 2 is selected (UPDM = 1 or 2 in “PWM Sync Channels Mode Register” ).
Figure 38-18. Synchronized Update of Update Period Value of Synchronous Channels
End of PWM period and
end of Update Period
of Synchronous Channels
PWM_SCUPUPD Value
User'sWriting
PWM_SCUP
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38.6.5.5 Changing the Comparison Value and the Comparison Configuration
It is possible to change the comparison values and the comparison configurations while the channel 0 is enabled
(see Section 38.6.3 “PWM Comparison Units”).
To prevent unexpected comparison match, the user must use the “PWM Comparison x Value Update Register”
and the “PWM Comparison x Mode Update Register” (PWM_CMPVUPDx and PWM_CMPMUPDx) to change
respectively the comparison values and the comparison configurations while the channel 0 is still enabled. These
registers hold the new values until the end of the comparison update period (when CUPRCNT is equal to CUPR in
“PWM Comparison x Mode Register” (PWM_CMPMx) and the end of the current PWM period, then update the
values for the next period.
CAUTION: to be taken into account, the write of the register PWM_CMPVUPDx must be followed by a write of the
register PWM_CMPMUPDx.
Note: If the update registers PWM_CMPVUPDx and PWM_CMPMUPDx are written several times between two updates,
only the last written value are taken into account.
Figure 38-19. Synchronized Update of Comparison Values and Configurations
PWM_CMPVUPDx Value
Comparison Value
for comparison x
User'sWriting
PWM_CMPVx
End of channel0 PWM period and
end of Comparison Update Period
PWM_CMPMUPDx Value
Comparison configuration
for comparison x
PWM_CMPMx
User'sWriting
End of channel0 PWM period and
end of Comparison Update Period and
and PWM_CMPMx written
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38.6.5.6 Interrupts
Depending on the interrupt mask in the PWM_IMR1 and PWM_IMR2 registers, an interrupt can be generated at
the end of the corresponding channel period (CHIDx in the PWM_ISR1 register), after a fault event (FCHIDx in the
PWM_ISR1 register), after a comparison match (CMPMx in the PWM_ISR2 register), after a comparison update
(CMPUx in the PWM_ISR2 register) or according to the transfer mode of the synchronous channels (WRDY,
ENDTX, TXBUFE and UNRE in the PWM_ISR2 register).
If the interrupt is generated by the flags CHIDx or FCHIDx, the interrupt remains active until a read operation in the
PWM_ISR1 register occurs.
If the interrupt is generated by the flags WRDY or UNRE or CMPMx or CMPUx, the interrupt remains active until a
read operation in the PWM_ISR2 register occurs.
A channel interrupt is enabled by setting the corresponding bit in the PWM_IER1 and PWM_IER2 registers. A
channel interrupt is disabled by setting the corresponding bit in the PWM_IDR1 and PWM_IDR2 registers.
38.6.5.7 Write Protect Registers
To prevent any single software error that may corrupt PWM behavior, the registers listed below can be write-
protected by writing the field WPCMD in the “PWM Write Protect Control Register” on page 1037 (PWM_WPCR).
They are divided into 6 groups:
Register group 0:
̶“PWM Clock Register” on page 1006
Register group 1:
̶“PWM Disable Register” on page 1008
Register group 2:
̶“PWM Sync Channels Mode Register” on page 1014
̶“PWM Channel Mode Register” on page 1044
̶“PWM Stepper Motor Mode Register” on page 1036
Register group 3:
̶“PWM Channel Period Register” on page 1048
̶“PWM Channel Period Update Register” on page 1049
Register group 4:
̶“PWM Channel Dead Time Register” on page 1051
̶“PWM Channel Dead Time Update Register” on page 1052
Register group 5:
̶“PWM Fault Mode Register” on page 1029
̶“PWM Fault Protection Value Register” on page 1032
̶“PWM Fault Protection Enable Register 1” on page 1033
̶“PWM Fault Protection Enable Register 2” on page 1034
There are two types of Write Protect:
Write Protect SW, which can be enabled or disabled.
Write Protect HW, which can just be enabled, only a hardware reset of the PWM controller can disable it.
Both types of Write Protect can be applied independently to a particular register group by means of the WPCMD
and WPRG fields in PWM_WPCR register. If at least one Write Protect is active, the register group is write-
protected. The field WPCMD allows to perform the following actions depending on its value:
0 = Disabling the Write Protect SW of the register groups of which the bit WPRG is at 1.
1 = Enabling the Write Protect SW of the register groups of which the bit WPRG is at 1.
2 = Enabling the Write Protect HW of the register groups of which the bit WPRG is at 1.
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At any time, the user can determine which Write Protect is active in which register group by the fields WPSWS and
WPHWS in the “PWM Write Protect Status Register” on page 1039 (PWM_WPSR).
If a write access in a write-protected register is detected, then the WPVS flag in the PWM_WPSR register is set
and the field WPVSRC indicates in which register the write access has been attempted, through its address offset
without the two LSBs.
The WPVS and PWM_WPSR fields are automatically reset after reading the PWM_WPSR register.
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38.7 Pulse Width Modulation (PWM) User Interface
Table 38-6. Register Mapping
Offset Register Name Access Reset
0x00 PWM Clock Register PWM_CLK Read-write 0x0
0x04 PWM Enable Register PWM_ENA Write-only –
0x08 PWM Disable Register PWM_DIS Write-only –
0x0C PWM Status Register PWM_SR Read-only 0x0
0x10 PWM Interrupt Enable Register 1 PWM_IER1 Write-only –
0x14 PWM Interrupt Disable Register 1 PWM_IDR1 Write-only –
0x18 PWM Interrupt Mask Register 1 PWM_IMR1 Read-only 0x0
0x1C PWM Interrupt Status Register 1 PWM_ISR1 Read-only 0x0
0x20 PWM Sync Channels Mode Register PWM_SCM Read-write 0x0
0x24 Reserved – – –
0x28 PWM Sync Channels Update Control Register PWM_SCUC Read-write 0x0
0x2C PWM Sync Channels Update Period Register PWM_SCUP Read-write 0x0
0x30 PWM Sync Channels Update Period Update Register PWM_SCUPUPD Write-only 0x0
0x34 PWM Interrupt Enable Register 2 PWM_IER2 Write-only –
0x38 PWM Interrupt Disable Register 2 PWM_IDR2 Write-only –
0x3C PWM Interrupt Mask Register 2 PWM_IMR2 Read-only 0x0
0x40 PWM Interrupt Status Register 2 PWM_ISR2 Read-only 0x0
0x44 PWM Output Override Value Register PWM_OOV Read-write 0x0
0x48 PWM Output Selection Register PWM_OS Read-write 0x0
0x4C PWM Output Selection Set Register PWM_OSS Write-only –
0x50 PWM Output Selection Clear Register PWM_OSC Write-only –
0x54 PWM Output Selection Set Update Register PWM_OSSUPD Write-only –
0x58 PWM Output Selection Clear Update Register PWM_OSCUPD Write-only –
0x5C PWM Fault Mode Register PWM_FMR Read-write 0x0
0x60 PWM Fault Status Register PWM_FSR Read-only 0x0
0x64 PWM Fault Clear Register PWM_FCR Write-only –
0x68 PWM Fault Protection Value Register PWM_FPV Read-write 0x0
0x6C PWM Fault Protection Enable Register 1 PWM_FPE1 Read-write 0x0
0x70 PWM Fault Protection Enable Register 2 PWM_FPE2 Read-write 0x0
0x74-0x78 Reserved – – –
0x7C PWM Event Line 0 Mode Register PWM_ELMR0 Read-write 0x0
0x80 PWM Event Line 1 Mode Register PWM_ELMR1 Read-write 0x0
0x84-AC Reserved – – –
0xB0 PWM Stepper Motor Mode Register PWM_SMMR Read-write 0x0
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0xB4-E0 Reserved – – –
0xE4 PWM Write Protect Control Register PWM_WPCR Write-only –
0xE8 PWM Write Protect Status Register PWM_WPSR Read-only 0x0
0xEC - 0xFC Reserved – – –
0x100 - 0x128 Reserved for PDC registers – – –
0x12C Reserved – – –
0x130 PWM Comparison 0 Value Register PWM_CMPV0 Read-write 0x0
0x134 PWM Comparison 0 Value Update Register PWM_CMPVUPD0 Write-only –
0x138 PWM Comparison 0 Mode Register PWM_CMPM0 Read-write 0x0
0x13C PWM Comparison 0 Mode Update Register PWM_CMPMUPD0 Write-only –
0x140 PWM Comparison 1 Value Register PWM_CMPV1 Read-write 0x0
0x144 PWM Comparison 1 Value Update Register PWM_CMPVUPD1 Write-only –
0x148 PWM Comparison 1 Mode Register PWM_CMPM1 Read-write 0x0
0x14C PWM Comparison 1 Mode Update Register PWM_CMPMUPD1 Write-only –
0x150 PWM Comparison 2 Value Register PWM_CMPV2 Read-write 0x0
0x154 PWM Comparison 2 Value Update Register PWM_CMPVUPD2 Write-only –
0x158 PWM Comparison 2 Mode Register PWM_CMPM2 Read-write 0x0
0x15C PWM Comparison 2 Mode Update Register PWM_CMPMUPD2 Write-only –
0x160 PWM Comparison 3 Value Register PWM_CMPV3 Read-write 0x0
0x164 PWM Comparison 3 Value Update Register PWM_CMPVUPD3 Write-only –
0x168 PWM Comparison 3 Mode Register PWM_CMPM3 Read-write 0x0
0x16C PWM Comparison 3 Mode Update Register PWM_CMPMUPD3 Write-only –
0x170 PWM Comparison 4 Value Register PWM_CMPV4 Read-write 0x0
0x174 PWM Comparison 4 Value Update Register PWM_CMPVUPD4 Write-only –
0x178 PWM Comparison 4 Mode Register PWM_CMPM4 Read-write 0x0
0x17C PWM Comparison 4 Mode Update Register PWM_CMPMUPD4 Write-only –
0x180 PWM Comparison 5 Value Register PWM_CMPV5 Read-write 0x0
0x184 PWM Comparison 5 Value Update Register PWM_CMPVUPD5 Write-only –
0x188 PWM Comparison 5 Mode Register PWM_CMPM5 Read-write 0x0
0x18C PWM Comparison 5 Mode Update Register PWM_CMPMUPD5 Write-only –
0x190 PWM Comparison 6 Value Register PWM_CMPV6 Read-write 0x0
0x194 PWM Comparison 6 Value Update Register PWM_CMPVUPD6 Write-only –
0x198 PWM Comparison 6 Mode Register PWM_CMPM6 Read-write 0x0
0x19C PWM Comparison 6 Mode Update Register PWM_CMPMUPD6 Write-only –
0x1A0 PWM Comparison 7 Value Register PWM_CMPV7 Read-write 0x0
0x1A4 PWM Comparison 7 Value Update Register PWM_CMPVUPD7 Write-only –
0x1A8 PWM Comparison 7 Mode Register PWM_CMPM7 Read-write 0x0
Table 38-6. Register Mapping (Continued)
Offset Register Name Access Reset
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Notes: 1. Some registers are indexed with “ch_num” index ranging from 0 to 7.
0x1AC PWM Comparison 7 Mode Update Register PWM_CMPMUPD7 Write-only –
0x1B0 - 0x1FC Reserved – – –
0x200 + ch_num *
0x20 + 0x00 PWM Channel Mode Register(1) PWM_CMR Read-write 0x0
0x200 + ch_num *
0x20 + 0x04 PWM Channel Duty Cycle Register(1) PWM_CDTY Read-write 0x0
0x200 + ch_num *
0x20 + 0x08 PWM Channel Duty Cycle Update Register(1) PWM_CDTYUPD Write-only –
0x200 + ch_num *
0x20 + 0x0C PWM Channel Period Register(1) PWM_CPRD Read-write 0x0
0x200 + ch_num *
0x20 + 0x10 PWM Channel Period Update Register(1) PWM_CPRDUPD Write-only –
0x200 + ch_num *
0x20 + 0x14 PWM Channel Counter Register(1) PWM_CCNT Read-only 0x0
0x200 + ch_num *
0x20 + 0x18 PWM Channel Dead Time Register(1) PWM_DT Read-write 0x0
0x200 + ch_num *
0x20 + 0x1C PWM Channel Dead Time Update Register(1) PWM_DTUPD Write-only –
Table 38-6. Register Mapping (Continued)
Offset Register Name Access Reset
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38.7.1 PWM Clock Register
Name: PWM_CLK
Address: 0x40094000
Access: Read-write
This register can only be written if the bits WPSWS0 and WPHWS0 are cleared in “PWM Write Protect Status Register” on
page 1039.
• DIVA, DIVB: CLKA, CLKB Divide Factor
• PREA, PREB: CLKA, CLKB Source Clock Selection
31 30 29 28 27 26 25 24
–––– PREB
23 22 21 20 19 18 17 16
DIVB
15 14 13 12 11 10 9 8
–––– PREA
76543210
DIVA
DIVA, DIVB CLKA, CLKB
0 CLKA, CLKB clock is turned off
1 CLKA, CLKB clock is clock selected by PREA, PREB
2-255 CLKA, CLKB clock is clock selected by PREA, PREB divided by DIVA, DIVB factor.
PREA, PREB Divider Input Clock
0000MCK
0001MCK/2
0010MCK/4
0011MCK/8
0100MCK/16
0101MCK/32
0110MCK/64
0111MCK/128
1000MCK/256
1001MCK/512
1010MCK/1024
Other Reserved
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38.7.2 PWM Enable Register
Name: PWM_ENA
Address: 0x40094004
Access: Write-only
• CHIDx: Channel ID
0 = No effect.
1 = Enable PWM output for channel x.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
CHID7 CHID6 CHID5 CHID4 CHID3 CHID2 CHID1 CHID0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1008
38.7.3 PWM Disable Register
Name: PWM_DIS
Address: 0x40094008
Access: Write-only
This register can only be written if the bits WPSWS1 and WPHWS1 are cleared in “PWM Write Protect Status Register” on
page 1039.
• CHIDx: Channel ID
0 = No effect.
1 = Disable PWM output for channel x.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
CHID7 CHID6 CHID5 CHID4 CHID3 CHID2 CHID1 CHID0
AtmeL
1009
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.4 PWM Status Register
Name: PWM_SR
Address: 0x4009400C
Access: Read-only
• CHIDx: Channel ID
0 = PWM output for channel x is disabled.
1 = PWM output for channel x is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
CHID7 CHID6 CHID5 CHID4 CHID3 CHID2 CHID1 CHID0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1010
38.7.5 PWM Interrupt Enable Register 1
Name: PWM_IER1
Address: 0x40094010
Access: Write-only
• CHIDx: Counter Event on Channel x Interrupt Enable
• FCHIDx: Fault Protection Trigger on Channel x Interrupt Enable
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FCHID7 FCHID6 FCHID5 FCHID4 FCHID3 FCHID2 FCHID1 FCHID0
15 14 13 12 11 10 9 8
––––––––
76543210
CHID7 CHID6 CHID5 CHID4 CHID3 CHID2 CHID1 CHID0
AtmeL
1011
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.6 PWM Interrupt Disable Register 1
Name: PWM_IDR1
Address: 0x40094014
Access: Write-only
• CHIDx: Counter Event on Channel x Interrupt Disable
• FCHIDx: Fault Protection Trigger on Channel x Interrupt Disable
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FCHID7 FCHID6 FCHID5 FCHID4 FCHID3 FCHID2 FCHID1 FCHID0
15 14 13 12 11 10 9 8
––––––––
76543210
CHID7 CHID6 CHID5 CHID4 CHID3 CHID2 CHID1 CHID0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1012
38.7.7 PWM Interrupt Mask Register 1
Name: PWM_IMR1
Address: 0x40094018
Access: Read-only
• CHIDx: Counter Event on Channel x Interrupt Mask
• FCHIDx: Fault Protection Trigger on Channel x Interrupt Mask
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FCHID7 FCHID6 FCHID5 FCHID4 FCHID3 FCHID2 FCHID1 FCHID0
15 14 13 12 11 10 9 8
––––––––
76543210
CHID7 CHID6 CHID5 CHID4 CHID3 CHID2 CHID1 CHID0
AtmeL
1013
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.8 PWM Interrupt Status Register 1
Name: PWM_ISR1
Address: 0x4009401C
Access: Read-only
• CHIDx: Counter Event on Channel x
0 = No new counter event has occurred since the last read of the PWM_ISR1 register.
1 = At least one counter event has occurred since the last read of the PWM_ISR1 register.
• FCHIDx: Fault Protection Trigger on Channel x
0 = No new trigger of the fault protection since the last read of the PWM_ISR1 register.
1 = At least one trigger of the fault protection since the last read of the PWM_ISR1 register.
Note: Reading PWM_ISR1 automatically clears CHIDx and FCHIDx flags.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FCHID7 FCHID6 FCHID5 FCHID4 FCHID3 FCHID2 FCHID1 FCHID0
15 14 13 12 11 10 9 8
––––––––
76543210
CHID7 CHID6 CHID5 CHID4 CHID3 CHID2 CHID1 CHID0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1014
38.7.9 PWM Sync Channels Mode Register
Name: PWM_SCM
Address: 0x40094020
Access: Read-write
This register can only be written if the bits WPSWS2 and WPHWS2 are cleared in “PWM Write Protect Status Register” on
page 1039.
• SYNCx: Synchronous Channel x
0 = Channel x is not a synchronous channel.
1 = Channel x is a synchronous channel.
• UPDM: Synchronous Channels Update Mode
Notes: 1. The update occurs at the beginning of the next PWM period, when the UPDULOCK bit in “PWM Sync Channels Update
Control Register” is set.
2. The update occurs when the Update Period is elapsed.
• PTRM: PDC Transfer Request Mode
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
PTRCS PTRM – – UPDM
15 14 13 12 11 10 9 8
––––––––
76543210
SYNC7 SYNC6 SYNC5 SYNC4 SYNC3 SYNC2 SYNC1 SYNC0
Value Name Description
0 MODE0 Manual write of double buffer registers and manual update of synchronous channels(1)
1 MODE1 Manual write of double buffer registers and automatic update of synchronous channels(2)
2MODE2
Automatic write of duty-cycle update registers by the PDC and automatic update of synchronous
channels(2)
3–Reserved
UPDM PTRM WRDY Flag and PDC Transfer Request
0x
The WRDY flag in “PWM Interrupt Status Register 2” on page 1022 and the PDC transfer request
are never set to 1.
1x
The WRDY flag in “PWM Interrupt Status Register 2” on page 1022 is set to 1 as soon as the
update period is elapsed, the PDC transfer request is never set to 1.
2
0The WRDY flag in “PWM Interrupt Status Register 2” on page 1022 and the PDC transfer request
are set to 1 as soon as the update period is elapsed.
1The WRDY flag in “PWM Interrupt Status Register 2” on page 1022 and the PDC transfer request
are set to 1 as soon as the selected comparison matches.
AtmeL
1015
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• PTRCS: PDC Transfer Request Comparison Selection
Selection of the comparison used to set the flag WRDY and the corresponding PDC transfer request.
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1016
38.7.10 PWM Sync Channels Update Control Register
Name: PWM_SCUC
Address: 0x40094028
Access: Read-write
• UPDULOCK: Synchronous Channels Update Unlock
0 = No effect
1 = If the UPDM field is set to “0” in “PWM Sync Channels Mode Register” on page 1014, writing the UPDULOCK bit to “1”
triggers the update of the period value, the duty-cycle and the dead-time values of synchronous channels at the beginning
of the next PWM period. If the field UPDM is set to “1” or “2”, writing the UPDULOCK bit to “1” triggers only the update of
the period value and of the dead-time values of synchronous channels.
This bit is automatically reset when the update is done.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––UPDULOCK
AtmeL
1017
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.11 PWM Sync Channels Update Period Register
Name: PWM_SCUP
Address: 0x4009402C
Access: Read-write
•UPR: Update Period
Defines the time between each update of the synchronous channels if automatic trigger of the update is activated
(UPDM = 1 or UPDM = 2 in “PWM Sync Channels Mode Register” on page 1014). This time is equal to UPR+1 periods of
the synchronous channels.
• UPRCNT: Update Period Counter
Reports the value of the Update Period Counter.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
UPRCNT UPR
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1018
38.7.12 PWM Sync Channels Update Period Update Register
Name: PWM_SCUPUPD
Address: 0x40094030
Access: Write-only
This register acts as a double buffer for the UPR value. This prevents an unexpected automatic trigger of the update of
synchronous channels.
• UPRUPD: Update Period Update
Defines the wanted time between each update of the synchronous channels if automatic trigger of the update is activated
(UPDM = 1 or UPDM = 2 in “PWM Sync Channels Mode Register” on page 1014). This time is equal to UPR+1 periods of
the synchronous channels.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––– UPRUPD
AtmeL
1019
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.13 PWM Interrupt Enable Register 2
Name: PWM_IER2
Address: 0x40094034
Access: Write-only
• WRDY: Write Ready for Synchronous Channels Update Interrupt Enable
• ENDTX: PDC End of TX Buffer Interrupt Enable
• TXBUFE: PDC TX Buffer Empty Interrupt Enable
• UNRE: Synchronous Channels Update Underrun Error Interrupt Enable
• CMPMx: Comparison x Match Interrupt Enable
• CMPUx: Comparison x Update Interrupt Enable
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CMPU7 CMPU6 CMPU5 CMPU4 CMPU3 CMPU2 CMPU1 CMPU0
15 14 13 12 11 10 9 8
CMPM7 CMPM6 CMPM5 CMPM4 CMPM3 CMPM2 CMPM1 CMPM0
76543210
––––UNRE TXBUFE ENDTX WRDY
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1020
38.7.14 PWM Interrupt Disable Register 2
Name: PWM_IDR2
Address: 0x40094038
Access: Write-only
• WRDY: Write Ready for Synchronous Channels Update Interrupt Disable
• ENDTX: PDC End of TX Buffer Interrupt Disable
• TXBUFE: PDC TX Buffer Empty Interrupt Disable
• UNRE: Synchronous Channels Update Underrun Error Interrupt Disable
• CMPMx: Comparison x Match Interrupt Disable
• CMPUx: Comparison x Update Interrupt Disable
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CMPU7 CMPU6 CMPU5 CMPU4 CMPU3 CMPU2 CMPU1 CMPU0
15 14 13 12 11 10 9 8
CMPM7 CMPM6 CMPM5 CMPM4 CMPM3 CMPM2 CMPM1 CMPM0
76543210
––––UNRE TXBUFE ENDTX WRDY
AtmeL
1021
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.15 PWM Interrupt Mask Register 2
Name: PWM_IMR2
Address: 0x4009403C
Access: Read-only
• WRDY: Write Ready for Synchronous Channels Update Interrupt Mask
• ENDTX: PDC End of TX Buffer Interrupt Mask
• TXBUFE: PDC TX Buffer Empty Interrupt Mask
• UNRE: Synchronous Channels Update Underrun Error Interrupt Mask
• CMPMx: Comparison x Match Interrupt Mask
• CMPUx: Comparison x Update Interrupt Mask
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CMPU7 CMPU6 CMPU5 CMPU4 CMPU3 CMPU2 CMPU1 CMPU0
15 14 13 12 11 10 9 8
CMPM7 CMPM6 CMPM5 CMPM4 CMPM3 CMPM2 CMPM1 CMPM0
76543210
––––UNRE TXBUFE ENDTX WRDY
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1022
38.7.16 PWM Interrupt Status Register 2
Name: PWM_ISR2
Address: 0x40094040
Access: Read-only
• WRDY: Write Ready for Synchronous Channels Update
0 = New duty-cycle and dead-time values for the synchronous channels cannot be written.
1 = New duty-cycle and dead-time values for the synchronous channels can be written.
• ENDTX: PDC End of TX Buffer
0 = The Transmit Counter register has not reached 0 since the last write of the PDC.
1 = The Transmit Counter register has reached 0 since the last write of the PDC.
• TXBUFE: PDC TX Buffer Empty
0 = PWM_TCR or PWM_TCNR has a value other than 0.
1 = Both PWM_TCR and PWM_TCNR have a value other than 0.
• UNRE: Synchronous Channels Update Underrun Error
0 = No Synchronous Channels Update Underrun has occurred since the last read of the PWM_ISR2 register.
1 = At least one Synchronous Channels Update Underrun has occurred since the last read of the PWM_ISR2 register.
• CMPMx: Comparison x Match
0 = The comparison x has not matched since the last read of the PWM_ISR2 register.
1 = The comparison x has matched at least one time since the last read of the PWM_ISR2 register.
• CMPUx: Comparison x Update
0 = The comparison x has not been updated since the last read of the PWM_ISR2 register.
1 = The comparison x has been updated at least one time since the last read of the PWM_ISR2 register.
Note: Reading PWM_ISR2 automatically clears flags WRDY, UNRE and CMPSx.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CMPU7 CMPU6 CMPU5 CMPU4 CMPU3 CMPU2 CMPU1 CMPU0
15 14 13 12 11 10 9 8
CMPM7 CMPM6 CMPM5 CMPM4 CMPM3 CMPM2 CMPM1 CMPM0
76543210
––––UNRE TXBUFE ENDTX WRDY
AtmeL
1023
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.17 PWM Output Override Value Register
Name: PWM_OOV
Address: 0x40094044
Access: Read-write
• OOVHx: Output Override Value for PWMH output of the channel x
0 = Override value is 0 for PWMH output of channel x.
1 = Override value is 1 for PWMH output of channel x.
• OOVLx: Output Override Value for PWML output of the channel x
0 = Override value is 0 for PWML output of channel x.
1 = Override value is 1 for PWML output of channel x.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
OOVL7 OOVL6 OOVL5 OOVL4 OOVL3 OOVL2 OOVL1 OOVL0
15 14 13 12 11 10 9 8
––––––––
76543210
OOVH7 OOVH6 OOVH5 OOVH4 OOVH3 OOVH2 OOVH1 OOVH0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1024
38.7.18 PWM Output Selection Register
Name: PWM_OS
Address: 0x40094048
Access: Read-write
• OSHx: Output Selection for PWMH output of the channel x
0 = Dead-time generator output DTOHx selected as PWMH output of channel x.
1 = Output override value OOVHx selected as PWMH output of channel x.
• OSLx: Output Selection for PWML output of the channel x
0 = Dead-time generator output DTOLx selected as PWML output of channel x.
1 = Output override value OOVLx selected as PWML output of channel x.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
OSL7 OSL6 OSL5 OSL4 OSL3 OSL2 OSL1 OSL0
15 14 13 12 11 10 9 8
––––––––
76543210
OSH7 OSH6 OSH5 OSH4 OSH3 OSH2 OSH1 OSH0
AtmeL
1025
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.19 PWM Output Selection Set Register
Name: PWM_OSS
Address: 0x4009404C
Access: Write-only
• OSSHx: Output Selection Set for PWMH output of the channel x
0 = No effect.
1 = Output override value OOVHx selected as PWMH output of channel x.
• OSSLx: Output Selection Set for PWML output of the channel x
0 = No effect.
1 = Output override value OOVLx selected as PWML output of channel x.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
OSSL7 OSSL6 OSSL5 OSSL4 OSSL3 OSSL2 OSSL1 OSSL0
15 14 13 12 11 10 9 8
––––––––
76543210
OSSH7 OSSH6 OSSH5 OSSH4 OSSH3 OSSH2 OSSH1 OSSH0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1026
38.7.20 PWM Output Selection Clear Register
Name: PWM_OSC
Address: 0x40094050
Access: Write-only
• OSCHx: Output Selection Clear for PWMH output of the channel x
0 = No effect.
1 = Dead-time generator output DTOHx selected as PWMH output of channel x.
• OSCLx: Output Selection Clear for PWML output of the channel x
0 = No effect.
1 = Dead-time generator output DTOLx selected as PWML output of channel x.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
OSCL7 OSCL6 OSCL5 OSCL4 OSCL3 OSCL2 OSCL1 OSCL0
15 14 13 12 11 10 9 8
––––––––
76543210
OSCH7 OSCH6 OSCH5 OSCH4 OSCH3 OSCH2 OSCH1 OSCH0
AtmeL
1027
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.21 PWM Output Selection Set Update Register
Name: PWM_OSSUPD
Address: 0x40094054
Access: Write-only
• OSSUPHx: Output Selection Set for PWMH output of the channel x
0 = No effect.
1 = Output override value OOVHx selected as PWMH output of channel x at the beginning of the next channel x PWM
period.
• OSSUPLx: Output Selection Set for PWML output of the channel x
0 = No effect.
1 = Output override value OOVLx selected as PWML output of channel x at the beginning of the next channel x PWM
period.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
OSSUPL7 OSSUPL6 OSSUPL5 OSSUPL4 OSSUPL3 OSSUPL2 OSSUPL1 OSSUPL0
15 14 13 12 11 10 9 8
––––––––
76543210
OSSUPH7 OSSUPH6 OSSUPH5 OSSUPH4 OSSUPH3 OSSUPH2 OSSUPH1 OSSUPH0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1028
38.7.22 PWM Output Selection Clear Update Register
Name: PWM_OSCUPD
Address: 0x40094058
Access: Write-only
• OSCUPHx: Output Selection Clear for PWMH output of the channel x
0 = No effect.
1 = Dead-time generator output DTOHx selected as PWMH output of channel x at the beginning of the next channel x
PWM period.
• OSCUPLx: Output Selection Clear for PWML output of the channel x
0 = No effect.
1 = Dead-time generator output DTOLx selected as PWML output of channel x at the beginning of the next channel x PWM
period.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
OSCUPL7 OSCUPDL6 OSCUPL5 OSCUPL4 OSCUPL3 OSCUPL2 OSCUPL1 OSCUPL0
15 14 13 12 11 10 9 8
––––––––
76543210
OSCUPH7 OSCUPH6 OSCUPH5 OSCUPH4 OSCUPH3 OSCUPH2 OSCUPH1 OSCUPH0
CAUTION: AtmeL
1029
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.23 PWM Fault Mode Register
Name: PWM_FMR
Address: 0x4009405C
Access: Read-write
This register can only be written if the bits WPSWS5 and WPHWS5 are cleared in “PWM Write Protect Status Register” on
page 1039.
• FPOL: Fault Polarity (fault input bit varies from 0 to 5)
For each field bit y (fault input number):
0 = The fault y becomes active when the fault input y is at 0.
1 = The fault y becomes active when the fault input y is at 1.
• FMOD: Fault Activation Mode (fault input bit varies from 0 to 5)
For each field bit y (fault input number):
0 = The fault y is active until the Fault condition is removed at the peripheral(1) level.
1 = The fault y stays active until the Fault condition is removed at the peripheral(1) level AND until it is cleared in the
“PWM Fault Clear Register” .
Note: 1. The Peripheral generating the fault.
• FFIL: Fault Filtering (fault input bit varies from 0 to 5)
For each field bit y (fault input number):
0 = The fault input y is not filtered.
1 = The fault input y is filtered.
CAUTION: To prevent an unexpected activation of the status flag FSy in the “PWM Fault Status Register” on page 1030,
the bit FMODy can be set to “1” only if the FPOLy bit has been previously configured to its final value.
31 30 29 28 27 26 25 24
–
23 22 21 20 19 18 17 16
FFIL
15 14 13 12 11 10 9 8
FMOD
76543210
FPOL
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1030
38.7.24 PWM Fault Status Register
Name: PWM_FSR
Address: 0x40094060
Access: Read-only
• FIV: Fault Input Value (fault input bit varies from 0 to 5)
For each field bit y (fault input number):
0 = The current sampled value of the fault input y is 0 (after filtering if enabled).
1 = The current sampled value of the fault input y is 1 (after filtering if enabled).
• FS: Fault Status (fault input bit varies from 0 to 5)
For each field bit y (fault input number):
0 = The fault y is not currently active.
1 = The fault y is currently active.
31 30 29 28 27 26 25 24
–
23 22 21 20 19 18 17 16
–
15 14 13 12 11 10 9 8
FS
76543210
FIV
AtmeL
1031
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.25 PWM Fault Clear Register
Name: PWM_FCR
Address: 0x40094064
Access: Write-only
• FCLR: Fault Clear (fault input bit varies from 0 to 5)
For each field bit y (fault input number):
0 = No effect.
1 = If bit y of FMOD field is set to 1 and if the fault input y is not at the level defined by the bit y of FPOL field, the fault
y is cleared and becomes inactive (FMOD and FPOL fields belong to “PWM Fault Mode Register” on page 1029), else
writing this bit to 1 has no effect.
31 30 29 28 27 26 25 24
–
23 22 21 20 19 18 17 16
–
15 14 13 12 11 10 9 8
–
76543210
FCLR
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1032
38.7.26 PWM Fault Protection Value Register
Name: PWM_FPV
Address: 0x40094068
Access: Read-write
This register can only be written if the bits WPSWS5 and WPHWS5 are cleared in “PWM Write Protect Status Register” on
page 1039.
• FPVHx: Fault Protection Value for PWMH output on channel x
0 = PWMH output of channel x is forced to 0 when fault occurs.
1 = PWMH output of channel x is forced to 1 when fault occurs.
• FPVLx: Fault Protection Value for PWML output on channel x
0 = PWML output of channel x is forced to 0 when fault occurs.
1 = PWML output of channel x is forced to 1 when fault occurs.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FPVL7 FPVL6 FPVL5 FPVL4 FPVL3 FPVL2 FPVL1 FPVL0
15 14 13 12 11 10 9 8
––––––––
76543210
FPVH7 FPVH6 FPVH5 FPVH4 FPVH3 FPVH2 FPVH1 FPVH0
CAUTION: AtmeL
1033
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.27 PWM Fault Protection Enable Register 1
Name: PWM_FPE1
Address: 0x4009406C
Access: Read-write
This register can only be written if the bits WPSWS5 and WPHWS5 are cleared in “PWM Write Protect Status Register” on
page 1039.
Only the first 6 bits (number of fault input pins) of fields FPE0, FPE1, FPE2 and FPE3 are significant.
• FPEx: Fault Protection Enable for channel x (fault input bit varies from 0 to 5)
For each field bit y (fault input number):
0 = Fault y is not used for the Fault Protection of channel x.
1 = Fault y is used for the Fault Protection of channel x.
CAUTION: To prevent an unexpected activation of the Fault Protection, the bit y of FPEx field can be set to “1” only if the
corresponding FPOL bit has been previously configured to its final value in “PWM Fault Mode Register” on page 1029.
31 30 29 28 27 26 25 24
FPE3
23 22 21 20 19 18 17 16
FPE2
15 14 13 12 11 10 9 8
FPE1
76543210
FPE0
CAUTION: AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1034
38.7.28 PWM Fault Protection Enable Register 2
Name: PWM_FPE2
Address: 0x40094070
Access: Read-write
This register can only be written if the bits WPSWS5 and WPHWS5 are cleared in “PWM Write Protect Status Register” on
page 1039.
Only the first 6 bits (number of fault input pins) of fields FPE4, FPE5, FPE6 and FPE7 are significant.
• FPEx: Fault Protection Enable for channel x (fault input bit varies from 0 to 5)
For each field bit y (fault input number):
0 = Fault y is not used for the Fault Protection of channel x.
1 = Fault y is used for the Fault Protection of channel x.
CAUTION: To prevent an unexpected activation of the Fault Protection, the bit y of FPEx field can be set to “1” only if the
corresponding FPOL bit has been previously configured to its final value in “PWM Fault Mode Register” on page 1029.
31 30 29 28 27 26 25 24
FPE7
23 22 21 20 19 18 17 16
FPE6
15 14 13 12 11 10 9 8
FPE5
76543210
FPE4
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.29 PWM Event Line x Register
Name: PWM_ELMRx
Address: 0x4009407C
Access: Read-write
• CSELy: Comparison y Selection
0 = A pulse is not generated on the event line x when the comparison y matches.
1 = A pulse is generated on the event line x when the comparison y match.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
CSEL7 CSEL6 CSEL5 CSEL4 CSEL3 CSEL2 CSEL1 CSEL0
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1036
38.7.30 PWM Stepper Motor Mode Register
Name: PWM_SMMR
Address: 0x400940B0
Access: Read-write
• GCENx: Gray Count ENable
0 = Disable gray count generation on PWML[2*x], PWMH[2*x], PWML[2*x +1], PWMH[2*x +1]
1 = enable gray count generation on PWML[2*x], PWMH[2*x], PWML[2*x +1], PWMH[2*x +1.
• DOWNx: DOWN Count
0 = Up counter.
1 = Down counter.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––DOWN3DOWN2DOWN1DOWN0
15 14 13 12 11 10 9 8
––––––––
76543210
––––GCEN3GCEN2GCEN1GCEN0
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1037
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.31 PWM Write Protect Control Register
Name: PWM_WPCR
Address: 0x400940E4
Access: Write-only
• WPCMD: Write Protect Command
This command is performed only if the WPKEY value is correct.
0 = Disable the Write Protect SW of the register groups of which the bit WPRGx is at 1.
1 = Enable the Write Protect SW of the register groups of which the bit WPRGx is at 1.
2 = Enable the Write Protect HW of the register groups of which the bit WPRGx is at 1.
Moreover, to meet security requirements, in this mode of operation, the PIO lines associated with PWM can not be
configured through the PIO interface, not even by the PIO controller.
3 = No effect.
Note: Only a hardware reset of the PWM controller can disable the Write Protect HW.
• WPRGx: Write Protect Register Group x
0 = The WPCMD command has no effect on the register group x.
1 = The WPCMD command is applied to the register group x.
• WPKEY: Write Protect Key
Should be written at value 0x50574D (“PWM” in ASCII). Writing any other value in this field aborts the write operation of the
WPCMD field. Always reads as 0.
List of register groups:
• Register group 0:
–“PWM Clock Register” on page 1006
• Register group 1:
–“PWM Disable Register” on page 1008
• Register group 2:
–“PWM Sync Channels Mode Register” on page 1014
–“PWM Channel Mode Register” on page 1044
–“PWM Stepper Motor Mode Register” on page 1036
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
WPRG5WPRG4WPRG3WPRG2WPRG1WPRG0 WPCMD
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1038
• Register group 3:
–“PWM Channel Period Register” on page 1048
–“PWM Channel Period Update Register” on page 1049
• Register group 4:
–“PWM Channel Dead Time Register” on page 1051
–“PWM Channel Dead Time Update Register” on page 1052
• Register group 5:
–“PWM Fault Mode Register” on page 1029
–“PWM Fault Protection Value Register” on page 1032
–“PWM Fault Protection Enable Register 1” on page 1033
–“PWM Fault Protection Enable Register 2” on page 1034
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1039
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.32 PWM Write Protect Status Register
Name: PWM_WPSR
Address: 0x400940E8
Access: Read-only
• WPSWSx: Write Protect SW Status
0 = The Write Protect SW x of the register group x is disabled.
1 = The Write Protect SW x of the register group x is enabled.
• WPHWSx: Write Protect HW Status
0 = The Write Protect HW x of the register group x is disabled.
1 = The Write Protect HW x of the register group x is enabled.
• WPVS: Write Protect Violation Status
0 = No Write Protect violation has occurred since the last read of the PWM_WPSR register.
1 = At least one Write Protect violation has occurred since the last read of the PWM_WPSR register. If this violation is an
unauthorized attempt to write a protected register, the associated violation is reported into field WPVSRC.
• WPVSRC: Write Protect Violation Source
When WPVS is active, this field indicates the write-protected register (through address offset) in which a write access has
been attempted.
Note: The two LSBs of the address offset of the write-protected register are not reported
Note: Reading PWM_WPSR automatically clears WPVS and WPVSRC fields.
31 30 29 28 27 26 25 24
WPVSRC
23 22 21 20 19 18 17 16
WPVSRC
15 14 13 12 11 10 9 8
– – WPHWS5 WPHWS4 WPHWS3 WPHWS2 WPHWS1 WPHWS0
76543210
WPVS – WPSWS5 WPSWS4 WPSWS3 WPSWS2 WPSWS1 WPSWS0
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1040
38.7.33 PWM Comparison x Value Register
Name: PWM_CMPVx
Address: 0x40094130 [0], 0x40094140 [1], 0x40094150 [2], 0x40094160 [3], 0x40094170 [4], 0x40094180 [5],
0x40094190 [6], 0x400941A0 [7]
Access: Read-write
Only the first 16 bits (channel counter size) of field CV are significant.
• CV: Comparison x Value
Define the comparison x value to be compared with the counter of the channel 0.
• CVM: Comparison x Value Mode
0 = The comparison x between the counter of the channel 0 and the comparison x value is performed when this counter is
incrementing.
1 = The comparison x between the counter of the channel 0 and the comparison x value is performed when this counter is
decrementing.
Note: This bit is useless if the counter of the channel 0 is left aligned (CALG = 0 in “PWM Channel Mode Register” on page 1044)
31 30 29 28 27 26 25 24
–––––––CVM
23 22 21 20 19 18 17 16
CV
15 14 13 12 11 10 9 8
CV
76543210
CV
CAUTION: AtmeL
1041
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.34 PWM Comparison x Value Update Register
Name: PWM_CMPVUPDx
Address: 0x40094134 [0], 0x40094144 [1], 0x40094154 [2], 0x40094164 [3], 0x40094174 [4], 0x40094184 [5],
0x40094194 [6], 0x400941A4 [7]
Access: Write-only
This register acts as a double buffer for the CV and CVM values. This prevents an unexpected comparison x match.
Only the first 16 bits (channel counter size) of field CVUPD are significant.
• CVUPD: Comparison x Value Update
Define the comparison x value to be compared with the counter of the channel 0.
• CVMUPD: Comparison x Value Mode Update
0 = The comparison x between the counter of the channel 0 and the comparison x value is performed when this counter is
incrementing.
1 = The comparison x between the counter of the channel 0 and the comparison x value is performed when this counter is
decrementing.
Note: This bit is useless if the counter of the channel 0 is left aligned (CALG = 0 in “PWM Channel Mode Register” on page 1044)
CAUTION: to be taken into account, the write of the register PWM_CMPVUPDx must be followed by a write of the register
PWM_CMPMUPDx.
31 30 29 28 27 26 25 24
–––––––CVMUPD
23 22 21 20 19 18 17 16
CVUPD
15 14 13 12 11 10 9 8
CVUPD
76543210
CVUPD
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1042
38.7.35 PWM Comparison x Mode Register
Name: PWM_CMPMx
Address: 0x40094138, 0x40094148, 0x40094158, 0x40094168, 0x40094178, 0x40094188,
0x40094198,0x400941A8
Access: Read-write
• CEN: Comparison x Enable
0 = The comparison x is disabled and can not match.
1 = The comparison x is enabled and can match.
• CTR: Comparison x Trigger
The comparison x is performed when the value of the comparison x period counter (CPRCNT) reaches the value defined
by CTR.
• CPR: Comparison x Period
CPR defines the maximum value of the comparison x period counter (CPRCNT). The comparison x value is performed
periodically once every CPR+1 periods of the channel 0 counter.
• CPRCNT: Comparison x Period Counter
Reports the value of the comparison x period counter.
Note: The field CPRCNT is read-only
• CUPR: Comparison x Update Period
Defines the time between each update of the comparison x mode and the comparison x value. This time is equal to
CUPR+1 periods of the channel 0 counter.
• CUPRCNT: Comparison x Update Period Counter
Reports the value of the comparison x update period counter.
Note: The field CUPRCNT is read-only
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CUPRCNT CUPR
15 14 13 12 11 10 9 8
CPRCNT CPR
76543210
CTR –––CEN
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1043
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.36 PWM Comparison x Mode Update Register
Name: PWM_CMPMUPDx
Address: 0x4009413C [0], 0x4009414C [1], 0x4009415C [2], 0x4009416C [3], 0x4009417C [4], 0x4009418C [5],
0x4009419C [6], 0x400941AC [7]
Access: Write-only
This register acts as a double buffer for the CEN, CTR, CPR and CUPR values. This prevents an unexpected comparison
x match.
• CENUPD: Comparison x Enable Update
0 = The comparison x is disabled and can not match.
1 = The comparison x is enabled and can match.
• CTRUPD: Comparison x Trigger Update
The comparison x is performed when the value of the comparison x period counter (CPRCNT) reaches the value defined
by CTR.
• CPRUPD: Comparison x Period Update
CPR defines the maximum value of the comparison x period counter (CPRCNT). The comparison x value is performed
periodically once every CPR+1 periods of the channel 0 counter.
• CUPRUPD: Comparison x Update Period Update
Defines the time between each update of the comparison x mode and the comparison x value. This time is equal to
CUPR+1 periods of the channel 0 counter.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––– CUPRUPD
15 14 13 12 11 10 9 8
–––– CPRUPD
76543210
CTRUPD – – – CENUPD
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1044
38.7.37 PWM Channel Mode Register
Name: PWM_CMRx [x=0..7]
Address: 0x40094200 [0], 0x40094220 [1], 0x40094240 [2], 0x40094260 [3], 0x40094280 [4], 0x400942A0 [5],
0x400942C0 [6], 0x400942E0 [7]
Access: Read-write
This register can only be written if the bits WPSWS2 and WPHWS2 are cleared in “PWM Write Protect Status Register” on
page 1039.
• CPRE: Channel Pre-scaler
• CALG: Channel Alignment
0 = The period is left aligned.
1 = The period is center aligned.
• CPOL: Channel Polarity
0 = The OCx output waveform (output from the comparator) starts at a low level.
1 = The OCx output waveform (output from the comparator) starts at a high level.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––DTLIDTHIDTE
15 14 13 12 11 10 9 8
–––––CESCPOLCALG
76543210
–––– CPRE
Value Name Description
0b0000 MCK Master clock
0b0001 MCK_DIV_2 Master clock/2
0b0010 MCK_DIV_4 Master clock/4
0b0011 MCK_DIV_8 Master clock/8
0b0100 MCK_DIV_16 Master clock/16
0b0101 MCK_DIV_32 Master clock/32
0b0110 MCK_DIV_64 Master clock/64
0b0111 MCK_DIV_128 Master clock/128
0b1000 MCK_DIV_256 Master clock/256
0b1001 MCK_DIV_512 Master clock/512
0b1010 MCK_DIV_1024 Master clock/1024
0b1011 CLKA Clock A
0b1100 CLKB Clock B
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• CES: Counter Event Selection
The bit CES defines when the channel counter event occurs when the period is center aligned (flag CHIDx in the “PWM
Interrupt Status Register 1” on page 1013).
CALG = 0 (Left Alignment):
0/1 = The channel counter event occurs at the end of the PWM period.
CALG = 1 (Center Alignment):
0 = The channel counter event occurs at the end of the PWM period.
1 = The channel counter event occurs at the end of the PWM period and at half the PWM period.
• DTE: Dead-Time Generator Enable
0 = The dead-time generator is disabled.
1 = The dead-time generator is enabled.
• DTHI: Dead-Time PWMHx Output Inverted
0 = The dead-time PWMHx output is not inverted.
1 = The dead-time PWMHx output is inverted.
• DTLI: Dead-Time PWMLx Output Inverted
0 = The dead-time PWMLx output is not inverted.
1 = The dead-time PWMLx output is inverted.
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1046
38.7.38 PWM Channel Duty Cycle Register
Name: PWM_CDTYx [x=0..7]
Address: 0x40094204 [0], 0x40094224 [1], 0x40094244 [2], 0x40094264 [3], 0x40094284 [4], 0x400942A4 [5],
0x400942C4 [6], 0x400942E4 [7]
Access: Read-write
Only the first 16 bits (channel counter size) are significant.
• CDTY: Channel Duty-Cycle
Defines the waveform duty-cycle. This value must be defined between 0 and CPRD (PWM_CPRx).
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CDTY
15 14 13 12 11 10 9 8
CDTY
76543210
CDTY
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.39 PWM Channel Duty Cycle Update Register
Name: PWM_CDTYUPDx [x=0..7]
Address: 0x40094208 [0], 0x40094228 [1], 0x40094248 [2], 0x40094268 [3], 0x40094288 [4], 0x400942A8 [5],
0x400942C8 [6], 0x400942E8 [7]
Access: Write-only.
This register acts as a double buffer for the CDTY value. This prevents an unexpected waveform when modifying the
waveform duty-cycle.
Only the first 16 bits (channel counter size) are significant.
• CDTYUPD: Channel Duty-Cycle Update
Defines the waveform duty-cycle. This value must be defined between 0 and CPRD (PWM_CPRx).
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CDTYUPD
15 14 13 12 11 10 9 8
CDTYUPD
76543210
CDTYUPD
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1048
38.7.40 PWM Channel Period Register
Name: PWM_CPRDx [x=0..7]
Address: 0x4009420C [0], 0x4009422C [1], 0x4009424C [2], 0x4009426C [3], 0x4009428C [4], 0x400942AC [5],
0x400942CC [6], 0x400942EC [7]
Access: Read-write
This register can only be written if the bits WPSWS3 and WPHWS3 are cleared in “PWM Write Protect Status Register” on
page 1039.
Only the first 16 bits (channel counter size) are significant.
• CPRD: Channel Period
If the waveform is left-aligned, then the output waveform period depends on the channel counter source clock and can be
calculated:
–By using the PWM master clock (MCK) divided by an X given prescaler value (with X being 1, 2, 4, 8, 16, 32,
64, 128, 256, 512, or 1024). The resulting period formula will be:
–By using the PWM master clock (MCK) divided by one of both DIVA or DIVB divider, the formula becomes,
respectively:
or
If the waveform is center-aligned, then the output waveform period depends on the channel counter source clock and can
be calculated:
–By using the PWM master clock (MCK) divided by an X given prescaler value (with X being 1, 2, 4, 8, 16, 32,
64, 128, 256, 512, or 1024). The resulting period formula will be:
–By using the PWM master clock (MCK) divided by one of both DIVA or DIVB divider, the formula becomes,
respectively:
or
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CPRD
15 14 13 12 11 10 9 8
CPRD
76543210
CPRD
XCPRD×()
MCK
-------------------------------
CRPD DIVA×()
MCK
------------------------------------------
CRPD DIVB×()
MCK
------------------------------------------
2XCPRD××()
MCK
----------------------------------------
2CPRD DIVA××()
MCK
---------------------------------------------------
2CPRD×DIVB×()
MCK
---------------------------------------------------
1049
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.41 PWM Channel Period Update Register
Name: PWM_CPRDUPDx [x=0..7]
Address: 0x40094210 [0], 0x40094230 [1], 0x40094250 [2], 0x40094270 [3], 0x40094290 [4], 0x400942B0 [5],
0x400942D0 [6], 0x400942F0 [7]
Access: Write-only
This register can only be written if the bits WPSWS3 and WPHWS3 are cleared in “PWM Write Protect Status Register” on
page 1039.
This register acts as a double buffer for the CPRD value. This prevents an unexpected waveform when modifying the
waveform period.
Only the first 16 bits (channel counter size) are significant.
• CPRDUPD: Channel Period Update
If the waveform is left-aligned, then the output waveform period depends on the channel counter source clock and can be
calculated:
–By using the PWM master clock (MCK) divided by an X given prescaler value (with X being 1, 2, 4, 8, 16, 32,
64, 128, 256, 512, or 1024). The resulting period formula will be:
–By using the PWM master clock (MCK) divided by one of both DIVA or DIVB divider, the formula becomes,
respectively:
or
If the waveform is center-aligned, then the output waveform period depends on the channel counter source clock and can
be calculated:
–By using the PWM master clock (MCK) divided by an X given prescaler value (with X being 1, 2, 4, 8, 16, 32,
64, 128, 256, 512, or 1024). The resulting period formula will be:
–By using the PWM master clock (MCK) divided by one of both DIVA or DIVB divider, the formula becomes,
respectively:
or
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CPRDUPD
15 14 13 12 11 10 9 8
CPRDUPD
76543210
CPRDUPD
X CPRDUPD×()
MCK
--------------------------------------------
CRPDUPD DIVA×()
MCK
--------------------------------------------------------
CRPDUPD DIVB×()
MCK
--------------------------------------------------------
2X CPRDUPD××()
MCK
------------------------------------------------------
2CPRDUPD DIVA××()
MCK
-----------------------------------------------------------------
2CPRDUPD×DIVB×()
MCK
-----------------------------------------------------------------
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1050
38.7.42 PWM Channel Counter Register
Name: PWM_CCNTx [x=0..7]
Address: 0x40094214 [0], 0x40094234 [1], 0x40094254 [2], 0x40094274 [3], 0x40094294 [4], 0x400942B4 [5],
0x400942D4 [6], 0x400942F4 [7]
Access: Read-only
Only the first 16 bits (channel counter size) are significant.
• CNT: Channel Counter Register
Channel counter value. This register is reset when:
•the channel is enabled (writing CHIDx in the PWM_ENA register).
•the channel counter reaches CPRD value defined in the PWM_CPRDx register if the waveform is left aligned.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CNT
15 14 13 12 11 10 9 8
CNT
76543210
CNT
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1051
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
38.7.43 PWM Channel Dead Time Register
Name: PWM_DTx [x=0..7]
Address: 0x40094218 [0], 0x40094238 [1], 0x40094258 [2], 0x40094278 [3], 0x40094298 [4], 0x400942B8 [5],
0x400942D8 [6], 0x400942F8 [7]
Access: Read-write
This register can only be written if the bits WPSWS4 and WPHWS4 are cleared in “PWM Write Protect Status Register” on
page 1039.
Only the first 12 bits (dead-time counter size) of fields DTH and DTL are significant.
• DTH: Dead-Time Value for PWMHx Output
Defines the dead-time value for PWMHx output. This value must be defined between 0 and CPRD-CDTY (PWM_CPRx
and PWM_CDTYx).
• DTL: Dead-Time Value for PWMLx Output
Defines the dead-time value for PWMLx output. This value must be defined between 0 and CDTY (PWM_CDTYx).
31 30 29 28 27 26 25 24
DTL
23 22 21 20 19 18 17 16
DTL
15 14 13 12 11 10 9 8
DTH
76543210
DTH
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1052
38.7.44 PWM Channel Dead Time Update Register
Name: PWM_DTUPDx [x=0..7]
Address: 0x4009421C [0], 0x4009423C [1], 0x4009425C [2], 0x4009427C [3], 0x4009429C [4], 0x400942BC [5],
0x400942DC [6], 0x400942FC [7]
Access: Write-only
This register can only be written if the bits WPSWS4 and WPHWS4 are cleared in “PWM Write Protect Status Register” on
page 1039.
This register acts as a double buffer for the DTH and DTL values. This prevents an unexpected waveform when modifying
the dead-time values.
Only the first 12 bits (dead-time counter size) of fields DTHUPD and DTLUPD are significant.
• DTHUPD: Dead-Time Value Update for PWMHx Output
Defines the dead-time value for PWMHx output. This value must be defined between 0 and CPRD-CDTY (PWM_CPRx
and PWM_CDTYx). This value is applied only at the beginning of the next channel x PWM period.
• DTLUPD: Dead-Time Value Update for PWMLx Output
Defines the dead-time value for PWMLx output. This value must be defined between 0 and CDTY (PWM_CDTYx). This
value is applied only at the beginning of the next channel x PWM period.
31 30 29 28 27 26 25 24
DTLUPD
23 22 21 20 19 18 17 16
DTLUPD
15 14 13 12 11 10 9 8
DTHUPD
76543210
DTHUPD
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1053
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39. USB On-The-Go Interface (UOTGHS)
39.1 Description
The Universal Serial Bus (USB) MCU device complies with the Universal Serial Bus (USB) 2.0 specification in all
speeds.
Each pipe/endpoint can be configured in one of several USB transfer types. It can be associated with one, two or
three banks of a DPRAM used to store the current data payload. If two or three banks are used, then one DPRAM
bank is read or written by the CPU or the DMA, while the other is read or written by the UOTGHS core. This feature
is mandatory for isochronous pipes/endpoints.
Table 39-1 on page 1053 describes the hardware configuration of the USB MCU device.
Note: Bit fields are presented throughout the document as follows: ‘REGISTER. FIELD’ (e.g. UOTGHS_CTRL.USBE)
39.2 Embedded Characteristics
Compatible with the USB 2.0 specification
Supports High (480Mbps), Full (12Mbps) and Low (1.5Mbps) speed communication and On-The-Go
10 pipes/endpoints
4096 bytes of Embedded Dual-Port RAM (DPRAM) for Pipes/Endpoints
Up to 3 memory banks per Pipe/Endpoint (Not for Control Pipe/Endpoint)
Flexible Pipe/Endpoint configuration and management with dedicated DMA channels
On-Chip UTMI transceiver including Pull-Ups/Pull-downs
On-Chip OTG pad including VBUS analog comparator
Table 39-1. Description of USB Pipes/Endpoints
Pipe/Endpoint Mnemonic Max. Nb.
Banks DMA High Band
Width Max. Pipe/
Endpoint Size Type
0 PEP_0 1 N N 64 Control
1 PEP_1 3 Y 1 1024 Isochronous/Bulk/Interrupt/Control
2 PEP_2 3 Y Y 1024 Isochronous/Bulk/Interrupt/Control
3 PEP_3 2 Y Y 1024 Isochronous/Bulk/Interrupt/Control
4 PEP_4 2 Y Y 1024 Isochronous/Bulk/Interrupt/Control
5 PEP_5 2 Y Y 1024 Isochronous/Bulk/Interrupt/Control
6 PEP_6 2 Y Y 1024 Isochronous/Bulk/Interrupt/Control
7 PEP_7 2 N Y 1024 Isochronous/Bulk/Interrupt/Control
8 PEP_8 2 _ Y 1024 Isochronous/Bulk/Interrupt/Control
9 PEP_9 2 _ Y 1024 Isochronous/Bulk/Interrupt/Control
AtmeL
SAM3X / SAM3A [DATASHEET]
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1054
39.3 Block Diagram
The UOTGHS provides a hardware device to interface a USB link to a data flow stored in a dual-port RAM
(DPRAM).
In normal operation (SPDCONF = 1), the UTMI transceiver requires the UTMI PLL (480 MHz). In case of Full or
Low speed only, for a lower consumption (SPDCONF = 0), the UTMI transceiver only requires 48 MHz.
Figure 39-1. UOTGHS Block Diagram
VBUS
UOTGID
UOTGVBOF
OTG
I/O
Controller
32 bits
System Clock
Domain USB Clock
Domain
Rd/Wr/Ready
APB
Interface
USB2.0
CORE
PEP
Alloc
AHB1
DMA
AHB0
Local
AHB
Slave
interface
Master
AHB
Multiplexer
Slave
DPRAM
UTMI
16/8 bits
APB bus
AHB bus
AHB bus
PMC
DP
DM
DFSDM
DFSDP
DHSDM
DHSDP
ctrl
status
USB_48M Clock (needed only when SPDCONF=1)
USB_480M Clock (needed only when SPDCONF=0)
MCK
1055
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.3.1 Application Block Diagram
39.3.1.1 Device Mode
Bus-Powered Device
Figure 39-2. Bus-Powered Device Application Block Diagram
Figure 39-3. Self-powered Device Application Block Diagram
USB
2.0 Core
VBUS
DFSDM
DFSDP
UOTGID
UOTGVBOF
OTG
I/O
Controller
UTMI
DHSDM
DHSDP
USB
Connector
VBus
D-
D+
ID
GND
39 ohms
39 ohms
3.3 V
Regulator
VDD
USB
2.0 Core
VBUS
DFSDM
DFSDP
UOTGID
UOTGVBOF
OTG
I/O
Controller
UTMI
DHSDM
DHSDP
USB
Connector
VBus
D-
D+
ID
GND
39 ohms
39 ohms
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1056
39.3.1.2 Host and OTG Modes
Figure 39-4. Host and OTG Application Block Diagram
39.3.2 I/O Lines Description
Table 39-2. I/O Lines Description
PIn Name Pin Description Type Active Level
UOTGVBOF USB VBus On/Off: Bus Power Control Port Output VBUSPO
VBUS VBus: Bus Power Measurement Port Input
D- Data -: Differential Data Line - Port Input/Output
D+ Data +: Differential Data Line + Port Input/Output
DFSDM FS Data -: Full-Speed Differential Data Line - Port Input/Output
DFSDP FS Data +: Full-Speed Differential Data Line + Port Input/Output
DHSDM HS Data -: Hi-Speed Differential Data Line - Port Input/Output
DHSDP HS Data +: Hi-Speed Differential Data Line + Port Input/Output
UOTGID USB Identification: Mini Connector Identification Port Input Low: Mini-A plug
High Z: Mini-B plug
USB
2.0 Core
VBUS
DFSDM
DFSDP
UOTGID
UOTGVBOF
OTG
I/O
Controller
UTMI
DHSDM
DHSDP
USB
Connector
VBus
D-
D+
ID
GND
39 ohms
39 ohms
5V DC/DC
Generator
VDD
AtmeL
1057
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.4 Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described below.
39.4.1 I/O Lines
The UOTGVBOF and UOTGID pins are multiplexed with I/O Controller lines and may also be multiplexed with
lines of other peripherals. In order to use them with the USB, the user must first configure the I/O Controller to
assign them to their USB peripheral functions.
If UOTGID is used, the I/O Controller must be configured to enable the internal pull-up resistor of its pin.
If UOTGVBOF or UOTGID is not used by the application, the corresponding pin can be used for other
purposes by the I/O Controller or by other peripherals.
39.4.2 Clocks
The clock for the UOTGHS bus interface is generated by the Power Management Controller. This clock can be
enabled or disabled in the Power Management Controller. It is recommended to disable the UOTGHS before
disabling the clock, to avoid freezing the UOTGHS in an undefined state.
The UOTGHS can work in two different modes:
Normal mode (SPDCONF =1) where High speed, Full speed and Low speed are available.
Low-power mode (SPDCONF =0) where Full speed and Low speed are available.
For normal mode:
1. Enable the UPLL 480MHz
2. Wait for the UPLL 480 MHz to be considered as locked by the PMC
3. Enable the UOTGHS Peripheral clock (PMC_PCER)
4. The UOTGHS will use USB_480 M clock (refer to the PMC).
For low-power mode:
1. As USB_48M must be set to 48 MHz (refer to the PMC), select either the PLLA or the UPLL (previously
set to ON), and program the PMC_USB register (source selection and divider)
2. Enable the UOTGCK bit (PMC_SCER)
3. Enable the UOTGHS Peripheral clock (PMC_PCER)
4. Put the UOTGHS in Low power mode (SPDCONF)
39.4.3 Interrupts
The UOTGHS interrupt request line is connected to the interrupt controller. Using the UOTGHS interrupt requires
the interrupt controller to be programmed first.
39.4.4 USB Pipe/Endpoint x FIFO Data Register (USBFIFOxDATA)
The application has access to each Pipe/Endpoint FIFO through its reserved 32 KB address space. The
application can access a 64 KB buffer linearly or fixedly as the DPRAM address increment is fully handled by
hardware. Byte, half-word and word access are supported. Data should be accessed in a big-endian way.
Disabling the UOTGHS (by writing a zero to the UOTGHS_CTRL.USBE bit) does not reset the DPRAM.
Table 39-3. I/O Lines
Instance Signal I/O Line Peripheral
UOTGHS UOTGID PB11 A
UOTGHS UOTGVBOF PB10 A
AtmeL
SAM3X / SAM3A [DATASHEET]
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1058
39.5 Functional Description
39.5.1 USB General Operation
39.5.1.1 Introduction
After a hardware reset, the UOTGHS is disabled. When enabled, the UOTGHS runs either in device mode or in
host mode according to the ID detection.
If the UOTGID pin is not connected to the ground, the UOTGID Pin State bit in the General Status register
(UOTGHS_SR.ID) is set (the internal pull-up resistor of the UOTGID pin must be enabled by the I/O Controller)
and device mode is engaged.
The UOTGHS_SR.ID bit is cleared when a low level has been detected on the UOTGID pin. Host mode is then
engaged.
39.5.1.2 Power-On and Reset
Figure 39-5 on page 1058 describes the UOTGHS main states.
Figure 39-5. General States
After a hardware reset, the UOTGHS is in the Reset state. In this state:
The macro is disabled. The UOTGHS Enable bit in the General Control register (UOTGHS_CTRL.USBE) is
zero.
The macro clock is stopped in order to minimize the power consumption. The Freeze USB Clock bit
(UOTGHS_CTRL.FRZCLK) is set.
The UTMI is in suspend mode.
The internal states and registers of the device and host modes are reset.
The DPRAM is not cleared and is accessible.
The UOTGHS_SR.ID and UOTGHS_SR.VBUS bits reflect the states of the UOTGID and VBUS input pins.
The OTG Pad Enable (UOTGHS_CTRL.OTGPADE) bit, the VBus Polarity (UOTGHS_CTRL.VBUSPO) bit,
the UOTGHS_CTRL.FRZCLK bit, the UOTGHS_CTRL.USBE bit, the UOTGID Pin Enable
(UOTGHS_CTRL.UIDE) bit, the UOTGHS Mode (UOTGHS_CTRL.UIMOD) bit, and the Low-Speed Mode
Force (UOTGHS_DEVCTRL.LS) bit can be written by software, so that the user can program pads and
speed before enabling the macro, but their value is only taken into account once the macro is enabled and
unfrozen.
After writing a one to UOTGHS_CTRL.USBE, the UOTGHS enters the Device or the Host mode (according to the
ID detection) in idle state.
Device
UOTGHS_CTRL.USBE = 0
UOTGHS_CTRL.USBE = 1
ID = 1
Macro off:
UOTGHS_CTRL.USBE = 0
Clock stopped:
UOTGHS_CTRL.FRZCLK = 1
UOTGHS_CTRL.USBE = 0
UOTGHS_CTRL_USBE = 0
HW
RESET
ID = 0
Reset
Host
UOTGHS_CTRL.USBE = 1
<any
other
state>
AtmeL
1059
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
The UOTGHS can be disabled at any time by writing a zero to UOTGHS_CTRL.USBE. In fact, writing a zero to
UOTGHS_CTRL.USBE acts as a hardware reset, except that the UOTGHS_CTRL.OTGPADE,
UOTGHS_CTRL.VBUSPO, UOTGHS_CTRL.FRZCLK, UOTGHS_CTRL.UIDE, UOTGHS_CTRL.UIMOD and,
UOTGHS_DEVCTRL.LS bits are not reset.
39.5.1.3 Interrupts
One interrupt vector is assigned to the USB interface. Figure 39-6 on page 1059 shows the structure of the USB
interrupt system.
Figure 39-6. Interrupt System
See Section 39.5.2.19 and Section 39.5.3.13 for further details about device and host interrupts.
UOTGHS_CTRL.IDTE
UOTGHS_SR.IDTI
UOTGHS_SR.VBUSTI
UOTGHS_CTRL.VBUSTE
UOTGHS_SR.SRPI
UOTGHS_CTRL.SRPE
UOTGHS_SR.VBERRI
UOTGHS_CTRL.VBERRE
UOTGHS_SR.BCERRI
UOTGHS_CTRL.BCERRE
UOTGHS_SR.ROLEEXI
UOTGHS_CTRL.ROLEEXE
UOTGHS_SR.HNPERRI
UOTGHS_CTRL.HNPERRE
UOTGHS_SR.STOI
UOTGHS_CTRL.STOE
USB General
Interrupt
USB Device
Interrupt
USB Host
Interrupt
USB
Interrupt
Asynchronous interrupt source
UOTGHS_DEVIMR.SUSPE
UOTGHS_DEVIMR.SUSP
UOTGHS_DEVIMR.SOF
UOTGHS_DEVIMR.SOFE
UOTGHS_DEVIMR.EORST
UOTGHS_DEVIMR.EORSTE
UOTGHS_DEVIMR.WAKEUP
UOTGHS_DEVIMR.WAKEUPE
UOTGHS_DEVIMR.EORSM
UOTGHS_DEVIMR.EORSME
UOTGHS_DEVIMR.UPRSM
UOTGHS_DEVIMR.UPRSME
UOTGHS_DEVIMR.EPXINT
UOTGHS_DEVIMR.EPXINTE
UOTGHS_DEVIMR.DMAXINT
UOTGHS_DEVIMR.DMAXINTE
UOTGHS_HSTIMR.DCONNIE
UOTGHS_HSTISR.DCONNI
UOTGHS_HSTISR.DDISCI
UOTGHS_HSTIMR.DDISCIE
UOTGHS_HSTISR.RSTI
UOTGHS_HSTIMR.RSTIE
UOTGHS_HSTISR.RSMEDI
UOTGHS_HSTIMR.RSMEDIE
UOTGHS_HSTISR.RXRSMI
UOTGHS_HSTIMR.RXRSMIE
UOTGHS_HSTISR.HSOFI
UOTGHS_HSTIMR.HSOFIE
UOTGHS_HSTISR.HWUPI
UOTGHS_HSTIMR.HWUPIE
UOTGHS_HSTISR.PXINT
UOTGHS_HSTIMR.PXINTE
UOTGHS_HSTISR.DMAXINT
UOTGHS_HSTIMR.DMAXINTE
UOTGHS_DEVEPTIMRx.TXINE
UOTGHS_DEVEPTISRx.TXINI
UOTGHS_DEVEPTISRx.RXOUTI
UOTGHS_DEVEPTIMRx.RXOUTE
UOTGHS_DEVEPTISRx.RXSTPI
UOTGHS_DEVEPTIMRx.RXSTPE
UOTGHS_DEVEPTISRx.UNDERFI
UOTGHS_DEVEPTIMRx.UNDERFE
UOTGHS_DEVEPTISRx.NAKOUTI
UOTGHS_DEVEPTIMRx.NAKOUTE
UOTGHS_DEVEPTISRx.NAKINI
UOTGHS_DEVEPTIMRx.NAKINE
UOTGHS_DEVEPTISRx.OVERFI
UOTGHS_DEVEPTIMRx.OVERFE
UOTGHS_DEVEPTISRx.STALLEDI
UOTGHS_DEVEPTIMRx.STALLEDE
UOTGHS_DEVEPTISRx.CRCERRI
UOTGHS_DEVEPTIMRx.CRCERRE
UOTGHS_DEVEPTISRx.SHORTPACKET
UOTGHS_DEVEPTIMRx.SHORTPACKETE
UOTGHS_DEVEPTISRx.DTSEQ=MDATA & UESTAX.RXOUTI
UOTGHS_DEVEPTIMRx.MDATAE
UOTGHS_HSTPIPIMRx.RXINE
UOTGHS_HSTPIPISRx.RXINI
UOTGHS_HSTPIPISRx.TXOUTI
UOTGHS_HSTPIPIMRx.TXOUTE
UOTGHS_HSTPIPISRx.TXSTPI
UOTGHS_HSTPIPIMRx.TXSTPE
UOTGHS_HSTPIPISRx.UNDERFI
UOTGHS_HSTPIPIMRx.UNDERFIE
UOTGHS_HSTPIPISRx.PERRI
UOTGHS_HSTPIPIMRx.PERRE
UOTGHS_HSTPIPISRx.NAKEDI
UOTGHS_HSTPIPIMRx.NAKEDE
UOTGHS_HSTPIPISRx.OVERFI
UOTGHS_HSTPIPIMRx.OVERFIE
UOTGHS_HSTPIPISRx.RXSTALLDI
UOTGHS_HSTPIPIMRx.RXSTALLDE
UOTGHS_HSTPIPISRx.CRCERRI
UOTGHS_HSTPIPIMRx.CRCERRE
UOTGHS_HSTPIPISRx.SHORTPACKETI
UOTGHS_HSTPIPIMRx.SHORTPACKETIE
UOTGHS_HSTPIPISRx.NBUSYBK
UOTGHS_HSTPIPIMRx.NBUSYBKE
UDDMAX_CONTROL.EOT_IRQ_EN
UOTGHS_DEVDMASTATUSx.EOT_STA
UOTGHS_DEVDMASTATUSx.EOCH_BUFF_STA
UDDMAX_CONTROL.EOBUFF_IRQ_EN
UOTGHS_DEVDMASTATUSx.DESC_LD_STA
UDDMAX_CONTROL.DESC_LD_IRQ_EN
UOTGHS_HSTDMACONTROLx.EOT_IRQ_EN
UOTGHS_HSTDMASTATUSx.EOT_STA
UOTGHS_HSTDMASTATUSx.EOCH_BUFF_STA
UOTGHS_HSTDMACONTROLx.EOBUFF_IRQ_EN
UOTGHS_HSTDMASTATUSx.DESC_LD_STA
UOTGHS_HSTDMACONTROLx.DESC_LD_IRQ_EN
USB Device
Endpoint X
Interrupt
USB Host
Pipe X
Interrupt
USB Device
DMA Channel X
Interrupt
USB Host
DMA Channel X
Interrupt
UOTGHS_DEVIMR.MSOFE
UOTGHS_DEVIMR.MSOF
UOTGHS_DEVEPTISRx.HBISOINERRI
UOTGHS_DEVEPTIMRx.HBISOINERRE
UOTGHS_DEVEPTISRx.HBISOFLUSHI
UOTGHS_DEVEPTIMRx.HBISOFLUSHE
UOTGHS_DEVEPTISRx.DTSEQ=DATAX & UESTAX.RXOUTI
UOTGHS_DEVEPTIMRx.DATAXE
UOTGHS_DEVEPTISRx.TRANSERR
UOTGHS_DEVEPTIMRx.TRANSERRE
UOTGHS_DEVEPTISRx.NBUSYBK
UOTGHS_DEVEPTIMRx.NBUSYBKE
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1060
There are two kinds of general interrupts: processing, i.e. their generation is part of the normal processing, and
exception, i.e. errors (not related to CPU exceptions).
The processing general interrupts are:
The ID Transition Interrupt (UOTGHS_SR.IDTI)
The VBus Transition Interrupt (UOTGHS_SR.VBUSTI)
The SRP Interrupt (UOTGHS_SR.SRPI)
The Role Exchange Interrupt (UOTGHS_SR.ROLEEXI)
The exception general interrupts are:
The VBus Error Interrupt (UOTGHS_SR.VBERRI)
The B-Connection Error Interrupt (UOTGHS_SR.BCERRI)
The HNP Error Interrupt (UOTGHS_SR.HNPERRI)
The Suspend Time-Out Interrupt (UOTGHS_SR.STOI)
39.5.1.4 MCU Power Modes
USB Suspend Mode
In peripheral mode, the Suspend Interrupt bit in the Device Global Interrupt register (UOTGHS_DEVISR.SUSP)
indicates that the USB line is in suspend mode. In this case, the transceiver is automatically set in suspend mode
to reduce the consumption.
Clock Frozen
The UOTGHS can be frozen when the USB line is in the suspend mode, by writing a one to the
UOTGHS_CTRL.FRZCLK bit, which reduces the power consumption.
In this case, it is still possible to access the following elements:
The UOTGHS_CTRL.OTGPADE, UOTGHS_CTRL.VBUSPO, UOTGHS_CTRL.FRZCLK,
UOTGHS_CTRL.USBE, UOTGHS_CTRL.UIDE, UOTGHS_CTRL.UIMOD and UOTGHS_DEVCTRL.LS
bits
Moreover, when UOTGHS_CTRL.FRZCLK is written to one, only the asynchronous interrupt sources may trigger
the USB interrupt:
The ID Transition Interrupt (UOTGHS_SR.IDTI)
The VBus Transition Interrupt (UOTGHS_SR.VBUSTI)
The Wake-up Interrupt (UOTGHS_DEVISR.WAKEUP)
The Host Wake-up Interrupt (UOTGHS_HSTISR.HWUPI)
AtmeL
1061
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.5.1.5 Speed Control
Device mode
When the USB interface is in device mode, the speed selection (full-speed or high-speed) is performed
automatically by the UOTGHS during the USB reset according to the host speed capability. At the end of the USB
reset, the UOTGHS enables or disables high-speed terminations and pull-up.
It is possible to restraint the UOTGHS to full-speed or low-speed mode by handling the UOTGHS_DEVCTRL.LS
and the Speed Configuration (UOTGHS_DEVCTRL.SPDCONF) bits in UOTGHS_DEVCTRL.
Host mode
When the USB interface is in host mode, internal pull-down resistors are connected on both D+ and D- and the
interface detects the speed of the connected device, which is reflected by the Speed Status
(UOTGHS_SR.SPEED) field.
39.5.1.6 DPRAM Management
Pipes and endpoints can only be allocated in ascending order, from the pipe/endpoint 0 to the last pipe/endpoint to
be allocated. The user shall therefore configure them in the same order.
The allocation of a pipe/endpoint x starts when the Endpoint Memory Allocate bit in the Endpoint x Configuration
register (UOTGHS_DEVEPTCFGx.ALLOC) is written to one. Then, the hardware allocates a memory area in the
DPRAM and inserts it between the x-1 and x+1 pipes/endpoints. The x+1 pipe/endpoint memory window slides up
and its data is lost. Note that the following pipe/endpoint memory windows (from x+2) do not slide.
Disabling a pipe, by writing a zero to the Pipe x Enable bit in the Pipe Enable/Reset register
(UOTGHS_HSTPIP.PENx), or disabling an endpoint, by writing a zero to the Endpoint x Enable bit in the Device
Endpoint register (UOTGHS_DEVEPT.EPENx), resets neither the UOTGHS_DEVEPTCFGx.ALLOC bit nor its
configuration:
the Pipe Banks (UOTGHS_HSTPIPCFGx.PBK) field,
the Pipe Size (UOTGHS_HSTPIPCFGx.PSIZE) field,
the Pipe Token (UOTGHS_HSTPIPCFGx.PTOKEN) field,
the Pipe Type (UOTGHS_HSTPIPCFGx.PTYPE) field,
the Pipe Endpoint Number (UOTGHS_HSTPIPCFGx.PEPNUM) field,
and the Pipe Interrupt Request Frequency (UOTGHS_HSTPIPCFGx.INTFRQ) field;
the Endpoint Banks (UOTGHS_DEVEPTCFGx.EPBK) field,
the Endpoint Size (UOTGHS_DEVEPTCFGx. EPSIZE) field,
the Endpoint Direction (UOTGHS_DEVEPTCFGx.EPDIR) field,
and the Endpoint Type (UOTGHS_DEVEPTCFGx.EPTYPE) field.
To free its memory, the user shall write a zero to the UOTGHS_DEVEPTCFGx.ALLOC bit. The x+1 pipe/endpoint
memory window then slides down and its data is lost. Note that the following pipe/endpoint memory windows (from
x+2) do not slide.
AAAAA
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1062
Figure 39-7 on page 1062 illustrates the allocation and reorganization of the DPRAM in a typical example.
Figure 39-7. Allocation and Reorganization of the DPRAM
1. The pipes/endpoints 0 to 5 are enabled, configured and allocated in ascending order. Each pipe/endpoint
then owns a memory area in the DPRAM.
2. The pipe/endpoint 3 is disabled, but its memory is kept allocated by the controller.
3. In order to free its memory, its UOTGHS_DEVEPTCFGx.ALLOC bit is written to zero. The pipe/endpoint 4
memory window slides down, but the pipe/endpoint 5 does not move.
4. If the user chooses to reconfigure the pipe/endpoint 3 with a larger size, the controller allocates a memory
area after the pipe/endpoint 2 memory area and automatically slides up the pipe/endpoint 4 memory window.
The pipe/endpoint 5 does not move and a memory conflict appears as the memory windows of the
pipes/endpoints 4 and 5 overlap. The data of these pipes/endpoints is potentially lost.
Note:
2. There is no way the data of the pipe/endpoint 0 can be lost (except if it is de-allocated) as the memory allocation
and de-allocation may affect only higher pipes/endpoints.
3. Deactivating then reactivating the same pipe/endpoint with the same configuration only modifies temporarily the
controller DPRAM pointer and size for this pipe/endpoint. Nothing changes in the DPRAM, higher endpoints seem
not to have been moved and their data is preserved as far as nothing has been written or received into them while
changing the allocation state of the first pipe/endpoint.
4. When the user writes a one to the UOTGHS_DEVEPTCFGx.ALLOC bit, the Configuration OK Status bit
(UOTGHS_DEVEPTISRx.CFGOK) is set only if the configured size and number of banks are correct as
compared to the endpoint maximal allowed values and to the maximal FIFO size (i.e. the DPRAM size). The
UOTGHS_DEVEPTISRx.CFGOK value does not consider memory allocation conflicts.
39.5.1.7 Pad Suspend
Figure 39-8 on page 1063 shows the pad behavior.
Free Memory
PEP0
PEP1
PEP2
PEP3
PEP4
PEP5
Free Memory
PEP0
PEP1
PEP2
PEP4
PEP5
Free Memory
PEP0
PEP1
PEP2
PEP4
PEP5
Pipe/Endpoint 3
Disabled
Pipe/Endpoint 3
Memory Freed
Free Memory
PEP0
PEP1
PEP2
PEP3 (larger size)
PEP5
Pipe/Endpoint 3
Activated
PEP4 Lost Memory
PEP4 Conflict
PEP3
(ALLOC stays at 1)
Pipes/Endpoints 0..5
Activated
Device:
UOTGHS_DEVEPT.EPENx = 1
UOTGHS_DEVEPTCFGx.ALLOC = 1
Host:
UOTGHS_HSTPIP.EPENx = 1
UOTGHS_HSTPIPCFGx.ALLOC = 1
Device:
UOTGHS_DEVEPT.EPEN3 = 0
Host:
UOTGHS_HSTPIP.EPEN3 = 0
Device:
UOTGHS_DEVEPTCFG3.ALLOC = 0
Host:
UOTGHS_HSTPIPCFG3.ALLOC = 0
Device:
UOTGHS_DEVEPT.EPEN3 = 1
UOTGHS_DEVEPTCFG3.ALLOC = 1
Host:
UOTGHS_HSTPIP.EPEN3 = 1
UOTGHS_HSTPIPCFG3.ALLOC = 1
AAAAA
1063
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Figure 39-8. Pad Behavior
In the Idle state, the pad is put in low-power consumption mode, i.e., the differential receiver of the USB pad
is off, and internal pull-downs with strong value (15 K) are set in both DP/DM to avoid floating lines.
In the Active state, the pad is working.
Figure 39-9 on page 1063 illustrates the pad events leading to a PAD state change.
Figure 39-9. Pad Events
The UOTGHS_DEVISR.SUSP bit is set and the Wake-Up Interrupt (UOTGHS_DEVISR.WAKEUP) bit is cleared
when a USB “Suspend” state has been detected on the USB bus. This event automatically puts the USB pad in
Idle state. The detection of a non-idle event sets UOTGHS_DEVISR.WAKEUP, clears UOTGHS_DEVISR.SUSP
and wakes up the USB pad.
The pad goes to the Idle state if the macro is disabled or if the UOTGHS_DEVCTRL.DETACH bit is written to one.
It returns to the Active state when UOTGHS_CTRL.USBE is written to one and UOTGHS_DEVCTRL.DETACH is
written to zero.
Idle
Active
UOTGHS_CTRL.USBE = 1
& UOTGHS_DEVCTRL.DETACH = 0
& Suspend
UOTGHS_CTRL.USBE = 0
| UOTGHS_DEVCTRL.DETACH = 1
| Suspend
UOTGHS_DEVISR.SUSP
pu-ekaw no deraelCdetceted dnepsuS
Wake-up detected Cleared by software to acknowledge the interrupt
UOTGHS_DEVISR.WAKEUP
PAD State
Active
Idle
Active
AtmeL
SAM3X / SAM3A [DATASHEET]
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1064
39.5.1.8 Customizing of OTG Timers
It is possible to refine some OTG timers thanks to the Timer Page (UOTGHS_CTRL.TIMPAGE) and Timer Value
(UOTGHS_CTRL.TIMVALUE) fields, as shown in Table 39-4 on page 1064.
Note: 1. “On-The-Go Supplement to the USB 2.0 Specification Revision 1.0a”.
UOTGHS_CTRL.TIMPAGE is used to select the OTG timer to access while UOTGHS_CTRL.TIMVALUE indicates
the time-out value of the selected timer.
UOTGHS_CTRL.TIMPAGE and UOTGHS_CTRL.TIMVALUE can be read or written. Before writing them, the user
shall unlock write accesses by writing a one to the Timer Access Unlock (UOTGHS_CTRL.UNLOCK) bit. This is
not required for read accesses, except before accessing UOTGHS_CTRL.TIMPAGE if it has to be written in order
to read the UOTGHS_CTRL.TIMVALUE field of another OTG timer.
39.5.1.9 Plug-In Detection
The USB connection is detected from the VBUS pad. Figure 39-10 on page 1064 shows the architecture of the
plug-in detector.
Figure 39-10. Plug-In Detection Input Block Diagram
The control logic of the VBUS pad outputs two signals:
The Session_valid signal is high when the voltage on the VBUS pad is higher than or equal to 1.4V.
The Va_Vbus_valid signal is high when the voltage on the VBUS pad is higher than or equal to 4.4V.
In device mode, the UOTGHS_SR.VBUS bit follows the Session_valid comparator output:
It is set when the voltage on the VBUS pad is higher than or equal to 1.4V.
It is cleared when the voltage on the VBUS pad is lower than 1.4V.
Table 39-4. Customizing of OTG Timers
TIMPAGE
0b00
AWaitVrise Time-Out
(see OTG Standard(1)
Section 6.6.5.1)
0b01
VbBusPulsing Time-Out
(see OTG Standard(1)
Section5.3.4)
0b10
PdTmOutCnt Time-Out
(see OTG Standard(1)
Section 5.3.2)
0b11
SRPDetTmOut Time-Out
(see OTG Standard(1)
Section 5.3.3)
TIMVALUE
00b 20 ms 15 ms 93 ms 10 µs
01b 50 ms 23 ms 105 ms 100 µs
10b 70 ms 31 ms 118 ms 1 ms
11b 100 ms 40 ms 131 ms 11 ms
VBUSTI
UOTGHS_SR
VBUS VBUS
UOTGHS_SR
GND
VDD
Pad Logic
Logic
Session_valid
Va_Vbus_valid
RPU
RPD
VBus_pulsing
VBus_discharge
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In host mode, the UOTGHS_SR.VBUS bit follows an hysteresis based on Session_valid and Va_Vbus_valid:
It is set when the voltage on the VBUS pad is higher than or equal to 4.4V.
It is cleared when the voltage on the VBUS pad is lower than 1.4V.
The VBus Transition interrupt (UOTGHS_SR.VBUSTI) bit is set on each transition of the UOTGHS_SR.VBUS bit.
The UOTGHS_SR.VBUS bit is effective whether the UOTGHS is enabled or not.
39.5.1.10 ID Detection
Figure 39-11 on page 1065 shows how the ID transitions are detected.
Figure 39-11. ID Detection Input Block Diagram
The USB mode (device or host) can be either detected from the UOTGID pin or software selected by writing to the
UOTGHS_CTRL.UIMOD bit, according to the UOTGHS_CTRL.UIDE bit. This allows the UOTGID pin to be used
as a general purpose I/O pin even when the USB interface is enabled.
By default, the UOTGID pin is selected (UOTGHS_CTRL.UIDE is written to one) and the UOTGHS is in device
mode (UOTGHS_SR.ID is one), which corresponds to the case where no Mini-A plug is connected, i.e. no plug or
a Mini-B plug is connected and the UOTGID pin is kept high by the internal pull-up resistor from the I/O Controller
(which must be enabled if UOTGID is used).
The ID Transition Interrupt (UOTGHS_SR.IDTI) bit is set on each transition of the UOTGHS_SR.ID bit, i.e. when a
Mini-A plug (host mode) is connected or disconnected. This does not occur when a Mini-B plug (device mode) is
connected or disconnected.
The UOTGHS_SR.ID bit is effective whether the UOTGHS is enabled or not.
39.5.2 USB Device Operation
39.5.2.1 Introduction
In device mode, the UOTGHS supports hi-, full- and low-speed data transfers.
In addition to the default control endpoint, 10 endpoints are provided, which can be configured with an
isochronous, bulk or interrupt type, as described in Table 39-1 on page 1053.
As the device mode starts in Idle state, the pad consumption is reduced to the minimum.
39.5.2.2 Power-On and Reset
Figure 39-12 on page 1066 describes the UOTGHS device mode main states.
RPU
UIMOD
UOTGHS_CTRL
USB_ID
ID
UOTGHS_SR
VDD
UIDE
UOTGHS_CTRL
1
0IDTI
UOTGHS_SR
I/O Controller
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Figure 39-12. Device Mode States
After a hardware reset, the UOTGHS device mode is in Reset state. In this state:
the macro clock is stopped to minimize the power consumption (UOTGHS_CTRL.FRZCLK is written to one),
the internal registers of the device mode are reset,
the endpoint banks are de-allocated,
neither D+ nor D- is pulled up (UOTGHS_DEVCTRL.DETACH is written to one).
D+ or D- will be pulled up according to the selected speed as soon as the UOTGHS_DEVCTRL.DETACH bit is
written to zero and VBus is present. See “Device mode” for further details.
When the UOTGHS is enabled (UOTGHS_CTRL.USBE is written to one) in device mode (UOTGHS_SR.ID is
one), its device mode state goes to the Idle state with minimal power consumption. This does not require the USB
clock to be activated.
The UOTGHS device mode can be disabled and reset at any time by disabling the UOTGHS (by writing a zero to
UOTGHS_CTRL.USBE) or when the host mode is engaged (UOTGHS_SR.ID is zero).
39.5.2.3 USB Reset
The USB bus reset is managed by hardware. It is initiated by a connected host.
When a USB reset is detected on the USB line, the following operations are performed by the controller:
All endpoints are disabled, except the default control endpoint.
The default control endpoint is reset (see Section 39.5.2.4 for more details).
The data toggle sequence of the default control endpoint is cleared.
At the end of the reset process, the End of Reset (UOTGHS_DEVISR.EORST) bit is set.
During a reset, the UOTGHS automatically switches to the Hi-Speed mode if the host is Hi-Speed capable
(the reset is called Hi-Speed reset). The user should observe the UOTGHS_SR.SPEED field to know the
speed running at the end of the reset (UOTGHS_DEVISR.EORST is one).
Reset
Idle
HW
UOTGHS_CTRL.USBE = 0
| UOTGHS_SR.ID = 0
<any
other
state>
UOTGHS_CTRL.USBE = 0
| UOTGHS_SR.ID = 0
& UOTGHS_SR.ID = 1
UOTGHS_CTRL.USBE = 1
UOTGHS_HSTCTRL.RESET
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39.5.2.4 Endpoint Reset
An endpoint can be reset at any time by writing a one to the Endpoint x Reset (UOTGHS_DEVEPT.EPRSTx) bit.
This is recommended before using an endpoint upon hardware reset or when a USB bus reset has been received.
This resets:
the internal state machine of this endpoint,
the receive and transmit bank FIFO counters,
all registers of this endpoint (UOTGHS_DEVEPTCFGx, UOTGHS_DEVEPTISRx, the Endpoint x Control
(UOTGHS_DEVEPTIMRx) register), except its configuration (UOTGHS_DEVEPTCFGx.ALLOC,
UOTGHS_DEVEPTCFGx.EPBK, UOTGHS_DEVEPTCFGx.EPSIZE, UOTGHS_DEVEPTCFGx.EPDIR,
UOTGHS_DEVEPTCFGx.EPTYPE) and the Data Toggle Sequence (UOTGHS_DEVEPTISRx.DTSEQ)
field.
Note: The interrupt sources located in the UOTGHS_DEVEPTISRx register are not cleared when a USB bus reset has been
received.
The endpoint configuration remains active and the endpoint is still enabled.
The endpoint reset may be associated with a clear of the data toggle sequence as an answer to the
CLEAR_FEATURE USB request. This can be achieved by writing a one to the Reset Data Toggle Set bit in the
Endpoint x Control Set register (UOTGHS_DEVEPTIERx.RSTDTS) (this will set the Reset Data Toggle
(UOTGHS_DEVEPTIMRx.RSTDT) bit).
In the end, the user has to write a zero to the UOTGHS_DEVEPT.EPRSTx bit to complete the reset operation and
to start using the FIFO.
39.5.2.5 Endpoint Activation
The endpoint is maintained inactive and reset (see Section 39.5.2.4 for more details) as long as it is disabled
(UOTGHS_DEVEPT.EPENx is written to zero). UOTGHS_DEVEPTISRx.DTSEQ is also reset.
The algorithm represented on Figure 39-13 on page 1067 must be followed in order to activate an endpoint.
Figure 39-13. Endpoint Activation Algorithm
As long as the endpoint is not correctly configured (UOTGHS_HSTPIPISRx.CFGOK is zero), the controller does
not acknowledge the packets sent by the host to this endpoint.
The UOTGHS_HSTPIPISRx.CFGOK bit is set provided that the configured size and number of banks are correct
as compared to the endpoint maximal allowed values (see Table 39-1 on page 1053) and to the maximal FIFO
size (i.e. the DPRAM size).
Endpoint
Activation
UOTGHS_HSTPIPISRx.CFCFGOK== 1?
ERROR
Yes
Endpoint
Activated
Enable the endpoint.
UOTGHS_DEVEPT.EPENx = 1
Test if the endpoint configuration is correct.
UOTGHS_DEVEPTCFGx
.EPTYPE
.EPDIR
.EPSIZE
.EPBK
.ALLOC
Configure the endpoint:
- type
- direction
- size
-
number of banks
Allocate the configured DPRAM banks.
No
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See Section 39.5.1.6 for more details about DPRAM management.
39.5.2.6 Address Setup
The USB device address is set up according to the USB protocol.
After all kinds of resets, the USB device address is 0.
The host starts a SETUP transaction with a SET_ADDRESS (addr) request.
The user writes this address to the USB Address (UOTGHS_DEVCTRL.UADD) field, and writes a zero to
the Address Enable (UOTGHS_DEVCTRL.ADDEN) bit, so the actual address is still 0.
The user sends a zero-length IN packet from the control endpoint.
The user enables the recorded USB device address by writing a one to UOTGHS_DEVCTRL.ADDEN.
Once the USB device address is configured, the controller filters the packets to only accept those targeting the
address stored in UOTGHS_DEVCTRL.UADD.
UOTGHS_DEVCTRL.UADD and UOTGHS_DEVCTRL.ADDEN shall not be written all at once.
UOTGHS_DEVCTRL.UADD and UOTGHS_DEVCTRL.ADDEN are cleared:
on a hardware reset,
when the UOTGHS is disabled (UOTGHS_CTRL.USBE written to zero),
when a USB reset is detected.
When UOTGHS_DEVCTRL.UADD or UOTGHS_DEVCTRL.ADDEN is cleared, the default device address 0 is
used.
39.5.2.7 Suspend and Wake-up
When an idle USB bus state has been detected for 3 ms, the controller sets the Suspend
(UOTGHS_DEVISR.SUSP) interrupt bit. The user may then write a one to the UOTGHS_CTRL.FRZCLK bit to
reduce the power consumption.
To recover from the Suspend mode, the user shall wait for the Wake-Up (UOTGHS_DEVISR.WAKEUP) interrupt
bit, which is set when a non-idle event is detected, then write a zero to UOTGHS_CTRL.FRZCLK.
As the UOTGHS_DEVISR.WAKEUP interrupt bit is set when a non-idle event is detected, it can occur whether the
controller is in the Suspend mode or not. The UOTGHS_DEVISR.SUSP and UOTGHS_DEVISR.WAKEUP
interrupts are thus independent, except that one bit is cleared when the other is set.
39.5.2.8 Detach
The reset value of the UOTGHS_DEVCTRL.DETACH bit is one.
It is possible to initiate a device re-enumeration by simply writing a one then a zero to
UOTGHS_DEVCTRL.DETACH.
UOTGHS_DEVCTRL.DETACH acts on the pull-up connections of the D+ and D- pads. See “Device mode” for
further details.
39.5.2.9 Remote Wake-up
The Remote Wake-Up request (also known as Upstream Resume) is the only one the device may send on its own
initiative, but the device should have beforehand been allowed to by a DEVICE_REMOTE_WAKEUP request from
the host.
First, the UOTGHS must have detected a “Suspend” state on the bus, i.e. the Remote Wake-Up request can
only be sent after a UOTGHS_DEVISR.SUSP interrupt has been set.
The user may then write a one to the Remote Wake-Up (UOTGHS_DEVCTRL.RMWKUP) bit to send an
upstream resume to the host for a remote wake-up. This will automatically be done by the controller after
5ms of inactivity on the USB bus.
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When the controller sends the upstream resume, the Upstream Resume (UOTGHS_DEVISR.UPRSM)
interrupt is set and UOTGHS_DEVISR.SUSP is cleared.
UOTGHS_DEVCTRL.RMWKUP is cleared at the end of the upstream resume.
If the controller detects a valid “End of Resume” signal from the host, the End of Resume
(UOTGHS_DEVISR.EORSM) interrupt is set.
39.5.2.10 STALL Request
For each endpoint, the STALL management is performed using:
The STALL Request (UOTGHS_DEVEPTIMRx.STALLRQ) bit to initiate a STALL request.
The STALLed Interrupt (UOTGHS_DEVEPTISRx.STALLEDI) bit, which is set when a STALL handshake has
been sent.
To answer the next request with a STALL handshake, UOTGHS_DEVEPTIMRx.STALLRQ has to be set by writing
a one to the STALL Request Set (UOTGHS_DEVEPTIERx.STALLRQS) bit. All following requests will be
discarded (UOTGHS_DEVEPTISRx.RXOUTI, etc. will not be set) and handshaked with a STALL until the
UOTGHS_DEVEPTIMRx.STALLRQ bit is cleared, which is done when a new SETUP packet is received (for
control endpoints) or when the STALL Request Clear (UOTGHS_DEVEPTIMRx.STALLRQC) bit is written to one.
Each time a STALL handshake is sent, the UOTGHS_DEVEPTISRx.STALLEDI bit is set by the UOTGHS and the
PEP_x interrupt is set.
Special considerations for control endpoints
If a SETUP packet is received into a control endpoint for which a STALL is requested, the Received SETUP
Interrupt (UOTGHS_DEVEPTISRx.RXSTPI) bit is set and UOTGHS_DEVEPTIMRx.STALLRQ and
UOTGHS_DEVEPTISRx.STALLEDI are cleared. The SETUP has to be ACKed.
This simplifies the enumeration process management. If a command is not supported or contains an error, the
user requests a STALL and can return to the main task, waiting for the next SETUP request.
STALL handshake and retry mechanism
The retry mechanism has priority over the STALL handshake. A STALL handshake is sent if the
UOTGHS_DEVEPTIMRx.STALLRQ bit is set and if no retry is required.
39.5.2.11 Management of Control Endpoints
Overview
A SETUP request is always ACKed. When a new SETUP packet is received, the
UOTGHS_DEVEPTISRx.RXSTPI is set; the Received OUT Data Interrupt (UOTGHS_DEVEPTISRx.RXOUTI) bit
is not.
The FIFO Control (UOTGHS_DEVEPTIMRx.FIFOCON) bit and the Read-write Allowed
(UOTGHS_DEVEPTISRx.RWALL) bit are irrelevant for control endpoints. The user shall never use them on these
endpoints. When read, their values are always zero.
Control endpoints are managed using:
the UOTGHS_DEVEPTISRx.RXSTPI bit, which is set when a new SETUP packet is received and which
shall be cleared by firmware to acknowledge the packet and to free the bank;
the UOTGHS_DEVEPTISRx.RXOUTI bit, which is set when a new OUT packet is received and which shall
be cleared by firmware to acknowledge the packet and to free the bank;
the Transmitted IN Data Interrupt (UOTGHS_DEVEPTISRx.TXINI) bit, which is set when the current bank is
ready to accept a new IN packet and which shall be cleared by firmware to send the packet.
( T L ”W XOXOIOIMIOXOIOIOIOKOXOIOIOIOI AtmeL
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Control write
Figure 39-14 on page 1070 shows a control write transaction. During the status stage, the controller will not
necessarily send a NAK on the first IN token:
if the user knows the exact number of descriptor bytes that must be read, it can then anticipate the status
stage and send a zero-length packet after the next IN token, or
it can read the bytes and wait for the NAKed IN Interrupt (UOTGHS_DEVEPTISRx.NAKINI), which tells that
all the bytes have been sent by the host and that the transaction is now in the status stage.
Figure 39-14. Control Write
Control read
Figure 39-15 on page 1070 shows a control read transaction. The UOTGHS has to manage the simultaneous write
requests from the CPU and the USB host.
Figure 39-15. Control Read
A NAK handshake is always generated on the first status stage command.
When the controller detects the status stage, all data written by the CPU is lost and clearing
UOTGHS_DEVEPTISRx.TXINI has no effect.
The user checks if the transmission or the reception is complete.
The OUT retry is always ACKed. This reception sets UOTGHS_DEVEPTISRx.RXOUTI and
UOTGHS_DEVEPTISRx.TXINI. Handle this with the following software algorithm:
set TXINI
wait for RXOUTI OR TXINI
if RXOUTI, then clear bit and return
if TXINI, then continue
SETUP
UOTGHS_DEVEPTISRx.RXSTPI
UOTGHS_DEVEPTISRx.RXOUTI
UOTGHS_DEVEPTISRx.TXINI
USB Bus
HW SW
OUT
HW SW
OUT
HW SW
IN IN
NAK
SW
DATA SUTATSPUTES
SETUP
UOTGHS_DEVEPTISRxRXSTPI
UOTGHS_DEVEPTISRx.RXOUTI
UOTGHS_DEVEPTISRx.TXINI
USB Bus
HW SW
IN
HW SW
IN OUT OUT
NAK
SW
SW
HW
Wr Enable
HOST
Wr Enable
CPU
DATA SUTATSPUTES
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Once the OUT status stage has been received, the UOTGHS waits for a SETUP request. The SETUP request has
priority over any other request and has to be ACKed. This means that any other bit should be cleared and the FIFO
reset when a SETUP is received.
The user has to consider that the byte counter is reset when a zero-length OUT packet is received.
39.5.2.12 Management of IN Endpoints
Overview
IN packets are sent by the USB device controller upon IN requests from the host. All data which acknowledges or
not the bank can be written when it is full.
The endpoint must be configured first.
The UOTGHS_DEVEPTISRx.TXINI bit is set at the same time as UOTGHS_DEVEPTIMRx.FIFOCON when the
current bank is free. This triggers a PEP_x interrupt if the Transmitted IN Data Interrupt Enable
(UOTGHS_DEVEPTIMRx.TXINE) bit is one.
UOTGHS_DEVEPTISRx.TXINI shall be cleared by software (by writing a one to the Transmitted IN Data Interrupt
Clear bit (UOTGHS_DEVEPTIDRx.TXINIC)) to acknowledge the interrupt, what has no effect on the endpoint
FIFO.
The user then writes into the FIFO and writes a one to the FIFO Control Clear
(UOTGHS_DEVEPTIDRx.FIFOCONC) bit to clear the UOTGHS_DEVEPTIMRx.FIFOCON bit. This allows the
UOTGHS to send the data. If the IN endpoint is composed of multiple banks, this also switches to the next bank.
The UOTGHS_DEVEPTISRx.TXINI and UOTGHS_DEVEPTIMRx.FIFOCON bits are updated in accordance with
the status of the next bank.
UOTGHS_DEVEPTISRx.TXINI shall always be cleared before clearing UOTGHS_DEVEPTIMRx.FIFOCON.
The UOTGHS_DEVEPTISRx.RWALL bit is set when the current bank is not full, i.e. the software can write further
data into the FIFO.
Figure 39-16. Example of an IN Endpoint with 1 Data Bank
IN DATA
(bank 0) ACK
UOTGHS_DEVEPTISRx.TXINI
UOTGHS_DEVEPTIMRx.FIFOCON
HW
write data to CPU
BANK 0 SW
SW SW
SW
IN
NAK
write data to CPU
BANK 0
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Figure 39-17. Example of an IN Endpoint with 2 Data Banks
Detailed description
The data is written, following the next flow:
When the bank is empty, UOTGHS_DEVEPTISRx.TXINI and UOTGHS_DEVEPTIMRx.FIFOCON are set,
which triggers a PEP_x interrupt if UOTGHS_DEVEPTIMRx.TXINE is one.
The user acknowledges the interrupt by clearing UOTGHS_DEVEPTISRx.TXINI.
The user writes the data into the current bank by using the USB Pipe/Endpoint nFIFO Data
(USBFIFOnDATA) register, until all the data frame is written or the bank is full (in which case
UOTGHS_DEVEPTISRx.RWALL is cleared and the Byte Count (UOTGHS_DEVEPTISRx.BYCT) field
reaches the endpoint size).
The user allows the controller to send the bank and switches to the next bank (if any) by clearing
UOTGHS_DEVEPTIMRx.FIFOCON.
If the endpoint uses several banks, the current one can be written while the previous one is being read by the host.
Then, when the user clears UOTGHS_DEVEPTIMRx.FIFOCON, the following bank may already be free and
UOTGHS_DEVEPTISRx.TXINI is set immediately.
An “Abort” stage can be produced when a zero-length OUT packet is received during an IN stage of a control or
isochronous IN transaction. The Kill IN Bank (UOTGHS_DEVEPTIMRx.KILLBK) bit is used to kill the last written
bank. The best way to manage this abort is to apply the algorithm represented on Figure 39-18 on page 1073.
IN DATA
(bank 0) ACK
UOTGHS_DEVEPTISRx.TXINI
UOTGHS_DEVEPTIMRx.FIFOCON write data to CPU
BANK 0 SW
SW SW
SW
IN DATA
(bank 1) ACK
write data to CPU
BANK 1
SW
HW
write data to CPU
BANK0
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Figure 39-18. Abort Algorithm
39.5.2.13 Management of OUT Endpoints
Overview
OUT packets are sent by the host. All data which acknowledges or not the bank can be read when it is empty.
The endpoint must be configured first.
The UOTGHS_DEVEPTISRx.RXOUTI bit is set at the same time as UOTGHS_DEVEPTIMRx.FIFOCON when the
current bank is full. This triggers a PEP_x interrupt if the Received OUT Data Interrupt Enable
(UOTGHS_DEVEPTIMRx.RXOUTE) bit is one.
UOTGHS_DEVEPTISRx.RXOUTI shall be cleared by software (by writing a one to the Received OUT Data
Interrupt Clear (UOTGHS_DEVEPTICRx.RXOUTIC) bit to acknowledge the interrupt, which has no effect on the
endpoint FIFO.
The user then reads from the FIFO and clears the UOTGHS_DEVEPTIMRx.FIFOCON bit to free the bank. If the
OUT endpoint is composed of multiple banks, this also switches to the next bank. The
UOTGHS_DEVEPTISRx.RXOUTI and UOTGHS_DEVEPTIMRx.FIFOCON bits are updated in accordance with
the status of the next bank.
UOTGHS_DEVEPTISRx.RXOUTI shall always be cleared before clearing UOTGHS_DEVEPTIMRx.FIFOCON.
The UOTGHS_DEVEPTISRx.RWALL bit is set when the current bank is not empty, i.e. the software can read
further data from the FIFO.
Endpoint
Abort
Abort Done
Abort is based on the fact
that no bank is busy, i.e.,
that nothing has to be sent
Disable the UOTGHS_DEVEPTISRx.TXINI interrupt.
UOTGHS_DEVEPT. EPRSTx = 1
UOTGHS_DEVEPTISRx.NBUSYBK == 0?
Yes
UOTGHS_DEVEPTIDRx.TXINEC = 1
No
UOTGHS_DEVEPTIERx.KILLBKS = 1
UOTGHS_DEVEPTIMRx.KILLBK == 1?
Yes
Kill the last written bank.
Wait for the end of the
procedure
No
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Figure 39-19. Example of an OUT Endpoint with one Data Bank
Figure 39-20. Example of an OUT Endpoint with two Data Banks
Detailed description
The data is read, following the next flow:
When the bank is full, UOTGHS_DEVEPTISRx.RXOUTI and UOTGHS_DEVEPTIMRx.FIFOCON are set,
which triggers a PEP_x interrupt if UOTGHS_DEVEPTIMRx.RXOUTE is one.
The user acknowledges the interrupt by writing a one to UOTGHS_DEVEPTICRx.RXOUTIC in order to clear
UOTGHS_DEVEPTISRx.RXOUTI.
The user can read the byte count of the current bank from UOTGHS_DEVEPTISRx.BYCT to know how
many bytes to read, rather than polling UOTGHS_DEVEPTISRx.RWALL.
The user reads the data from the current bank by using the USBFIFOnDATA register, until all expected data
frame is read or the bank is empty (in which case UOTGHS_DEVEPTISRx.RWALL is cleared and
UOTGHS_DEVEPTISRx.BYCT reaches zero).
The user frees the bank and switches to the next bank (if any) by clearing
UOTGHS_DEVEPTIMRx.FIFOCON.
If the endpoint uses several banks, the current one can be read while the following one is being written by the host.
Then, when the user clears UOTGHS_DEVEPTIMRx.FIFOCON, the following bank may already be read and
UOTGHS_DEVEPTISRx.RXOUTI is set immediately.
In Hi-Speed mode, the PING and NYET protocols are handled by the UOTGHS.
For a single bank, a NYET handshake is always sent to the host (on Bulk-out transaction) to indicate that the
current packet is acknowledged but there is no room for the next one.
For a double bank, the UOTGHS responds to the OUT/DATA transaction with an ACK handshake when the
endpoint accepted the data successfully and has room for another data payload (the second bank is free).
OUT DATA
(bank 0) ACK
UOTGHS_DEVEPTISRx.RXOUTI
UOTGHS_DEVEPTIMRx.FIFOCON
HW
OUT DATA
(bank 0) ACK
HW
SW
SW
SW
read data from CPU
BANK 0 read data from CPU
BANK 0
NAK
OUT DATA
(bank 0) ACK
UOTGHS_DEVEPTISRx.RXOUTI
UOTGHS_DEVEPTIMRx.FIFOCON
HW
OUT DATA
(bank 1) ACK
SW
SW
read data from CPU
BANK 0
HW
SW
read data from CPU
BANK 1
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39.5.2.14 Underflow
This error only exists for isochronous IN/OUT endpoints. It sets the Underflow Interrupt
(UOTGHS_DEVEPTISRx.UNDERFI) bit, which triggers a PEP_x interrupt if the Underflow Interrupt Enable
(UOTGHS_DEVEPTIMRx.UNDERFE) bit is one.
An underflow can occur during the IN stage if the host attempts to read from an empty bank. A zero-length
packet is then automatically sent by the UOTGHS.
An underflow cannot occur during the OUT stage on a CPU action, since the user may only read if the bank
is not empty (UOTGHS_DEVEPTISRx.RXOUTI is one or UOTGHS_DEVEPTISRx.RWALL is one).
An underflow can also occur during the OUT stage if the host sends a packet while the bank is already full.
Typically, the CPU is not fast enough. The packet is lost.
An underflow cannot occur during the IN stage on a CPU action, since the user may only write if the bank is
not full (UOTGHS_DEVEPTISRx.TXINI is one or UOTGHS_DEVEPTISRx.RWALL is one).
39.5.2.15 Overflow
This error exists for all endpoint types. It sets the Overflow interrupt (UOTGHS_DEVEPTISRx.OVERFI) bit, which
triggers a PEP_x interrupt if the Overflow Interrupt Enable (UOTGHS_DEVEPTIMRx.OVERFE) bit is one.
An overflow can occur during the OUT stage if the host attempts to write into a bank which is too small for
the packet. The packet is acknowledged and the UOTGHS_DEVEPTISRx.RXOUTI bit is set as if no
overflow had occurred. The bank is filled with all the first bytes of the packet that fit in.
An overflow cannot occur during the IN stage on a CPU action, since the user may only write if the bank is
not full (UOTGHS_DEVEPTISRx.TXINI is one or UOTGHS_DEVEPTISRx.RWALL is one).
39.5.2.16 HB IsoIn Error
This error only exists for high-bandwidth isochronous IN endpoints.
At the end of the micro-frame, if at least one packet has been sent to the host and less banks than expected have
been validated (by clearing the UOTGHS_DEVEPTIMRx.UOTGHS_DEVEPTIMRx.FIFOCON) for this micro-
frame, it sets the UOTGHS_DEVEPTISRx.HBISOINERRORI bit, which triggers a PEP_x interrupt if the High
Bandwidth Isochronous IN Error Interrupt Enable (HBISOINERRORE) bit is one.
For instance, if the Number of Transaction per MicroFrame for Isochronous Endpoint (NBTRANS field in
UOTGHS_DEVEPTCFGx is three (three transactions per micro-frame), only two banks are filled by the CPU
(three expected) for the current micro-frame. Then, the HBISOINERRI interrupt is generated at the end of the
micro-frame. Note that an UNDERFI interrupt is also generated (with an automatic zero-length-packet), except in
the case of a missing IN token.
39.5.2.17 HB IsoFlush
This error only exists for high-bandwidth isochronous IN endpoints.
At the end of the micro-frame, if at least one packet has been sent to the host and there is a missing IN token
during this micro-frame, the bank(s) destined to this micro-frame is/are flushed out to ensure a good data
synchronization between the host and the device.
For instance, if NBTRANS is three (three transactions per micro-frame), if only the first IN token (among 3) is well
received by the UOTGHS, then the two last banks will be discarded.
39.5.2.18 CRC Error
This error only exists for isochronous OUT endpoints. It sets the CRC Error Interrupt
(UOTGHS_DEVEPTISRx.CRCERRI) bit, which triggers a PEP_x interrupt if the CRC Error Interrupt Enable
(UOTGHS_DEVEPTIMRx.CRCERRE) bit is one.
A CRC error can occur during the OUT stage if the UOTGHS detects a corrupted received packet. The OUT
packet is stored in the bank as if no CRC error had occurred (UOTGHS_DEVEPTISRx.RXOUTI is set).
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39.5.2.19 Interrupts
See the structure of the USB device interrupt system on Figure 39-6 on page 1059.
There are two kinds of device interrupts: processing, i.e. their generation is part of the normal processing, and
exception, i.e. errors (not related to CPU exceptions).
Global interrupts
The processing device global interrupts are:
The Suspend (UOTGHS_DEVISR.SUSP) interrupt
The Start of Frame (UOTGHS_DEVISR.SOF) interrupt with no frame number CRC error - the Frame
Number CRC Error (UOTGHS_DEVFNUM.FNCERR) bit is zero.
The Micro Start of Frame (UOTGHS_DEVISR.MSOF) interrupt with no CRC error.
The End of Reset (UOTGHS_DEVISR.EORST) interrupt
The Wake-Up (UOTGHS_DEVISR.WAKEUP) interrupt
The End of Resume (UOTGHS_DEVISR.EORSM) interrupt
The Upstream Resume (UOTGHS_DEVISR.UPRSM) interrupt
The Endpoint x (UOTGHS_DEVISR.PEP_x) interrupt
The DMA Channel x (UOTGHS_DEVISR.DMA_x) interrupt
The exception device global interrupts are:
The Start of Frame (UOTGHS_DEVISR.SOF) interrupt with a frame number CRC error
(UOTGHS_DEVFNUM.FNCERR. is one)
The Micro Start of Frame (UOTGHS_DEVFNUM.FNCERR.MSOF) interrupt with a CRC error
Endpoint Interrupts
The processing device endpoint interrupts are:
The Transmitted IN Data Interrupt (UOTGHS_DEVEPTISRx.TXINI)
The Received OUT Data Interrupt (UOTGHS_DEVEPTISRx.RXOUTI)
The Received SETUP Interrupt (UOTGHS_DEVEPTISRx.RXSTPI)
The Short Packet (UOTGHS_DEVEPTISRx.SHORTPACKET) interrupt
The Number of Busy Banks (UOTGHS_DEVEPTISRx.NBUSYBK) interrupt
The Received OUT isochronous Multiple Data Interrupt (DTSEQ=MDATA &
UOTGHS_DEVEPTISRx.RXOUTI)
The Received OUT isochronous DataX Interrupt (DTSEQ=DATAX & UOTGHS_DEVEPTISRx.RXOUTI)
The exception device endpoint interrupts are:
The Underflow Interrupt (UOTGHS_DEVEPTISRx.UNDERFI)
The NAKed OUT Interrupt (UOTGHS_DEVEPTISRx.NAKOUTI)
The High-bandwidth isochronous IN error Interrupt (UOTGHS_DEVEPTISRx.HBISOINERRI)
The NAKed IN Interrupt (UOTGHS_DEVEPTISRx.NAKINI)
The High-bandwidth isochronous IN Flush error Interrupt (UOTGHS_DEVEPTISRx.HBISOFLUSHI)
The Overflow Interrupt (UOTGHS_DEVEPTISRx.OVERFI)
The STALLed Interrupt (UOTGHS_DEVEPTISRx.STALLEDI)
The CRC Error Interrupt (UOTGHS_DEVEPTISRx.CRCERRI)
The Transaction error (UOTGHS_DEVEPTISRx.ERRORTRANS) interrupt
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DMA interrupts
The processing device DMA interrupts are:
The End of USB Transfer Status (UOTGHS_DEVDMASTATUSx.END_TR_ST) interrupt
The End of Channel Buffer Status (UOTGHS_DEVDMASTATUSx.END_BF_ST) interrupt
The Descriptor Loaded Status (UOTGHS_DEVDMASTATUSx.DESC_LDST) interrupt
There is no exception device DMA interrupt.
39.5.2.20 Test Modes
When written to one, the UOTGHS_DEVCTRL.TSTPCKT bit switches the USB device controller in a “test packet”
mode:
The transceiver repeatedly transmits the packet stored in the current bank. UOTGHS_DEVCTRL.TSTPCKT must
be written to zero to exit the “test-packet” mode. The endpoint shall be reset by software after a “test-packet”
mode.
This enables the testing of rise and falling times, eye patterns, jitter, and any other dynamic waveform
specifications.
The flow control used to send the packets is as follows:
UOTGHS_DEVCTRL.TSTPCKT=1;
Store data in an endpoint bank
Write a zero to UOTGHS_DEVEPTIDRx.FIFOCON bit
To stop the test-packet mode, just write a zero to the UOTGHS_DEVCTRL.TSTPCKT bit.
39.5.3 USB Host Operation
39.5.3.1 Description of Pipes
For the UOTGHS in host mode, the term “pipe” is used instead of “endpoint” (used in device mode). A host pipe
corresponds to a device endpoint, as described in Figure 39-21 on page 1077 from the USB specification.
Figure 39-21. USB Communication Flow
In host mode, the UOTGHS associates a pipe to a device endpoint, considering the device configuration
descriptors.
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39.5.3.2 Power-On and Reset
Figure 39-22 on page 1078 describes the UOTGHS host mode main states.
Figure 39-22. Host Mode States
After a hardware reset, the UOTGHS host mode is in the Reset state.
When the UOTGHS is enabled (UOTGHS_CTRL.USBE is one) in host mode (UOTGHS_SR.ID is zero), it goes to
the Idle state. In this state, the controller waits for a device connection with a minimal power consumption. The
USB pad should be in the Idle state. Once a device is connected, the macro enters the Ready state, which does
not require the USB clock to be activated.
The controller enters the Suspend state when the USB bus is in a “Suspend” state, i.e., when the host mode does
not generate the “Start of Frame (SOF)”. In this state, the USB consumption is minimal. The host mode exits the
Suspend state when starting to generate the SOF over the USB line.
39.5.3.3 Device Detection
A device is detected by the UOTGHS host mode when D+ or D- is no longer tied low, i.e., when the device D+ or
D- pull-up resistor is connected. To enable this detection, the host controller has to provide the VBus power supply
to the device by writing a one to the UOTGHS_SFR.VBUSRQS bit.
The device disconnection is detected by the host controller when both D+ and D- are pulled down.
39.5.3.4 USB Reset
The UOTGHS sends a USB bus reset when the user write a one to the Send USB Reset bit in the Host General
Control register (UOTGHS_HSTCTRL.RESET). The USB Reset Sent Interrupt bit in the Host Global Interrupt
Status register (UOTGHS_HSTISR.RSTI) is set when the USB reset has been sent. In this case, all pipes are
disabled and de-allocated.
If the bus was previously in a “Suspend” state (the Start of Frame Generation Enable
(UOTGHS_HSTCTRL.SOFE) bit is zero), the UOTGHS automatically switches to the “Resume” state, the Host
Wake-Up Interrupt (UOTGHS_HSTISR.HWUPI) bit is set and the UOTGHS_HSTCTRL.SOFE bit is set in order to
generate SOFs or micro SOFs immediately after the USB reset.
At the end of the reset, the user should check the UOTGHS_SR.SPEED field to know the speed running according
to the peripheral capability (LS.FS/HS)
Ready
Idle
Device
Disconnection
<any
other
state>
Device
Connection
Macro off
Clock stopped
Device
Disconnection
Suspend
SOFE = 1
SOFE = 0
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39.5.3.5 Pipe Reset
A pipe can be reset at any time by writing a one to the Pipe x Reset (UOTGHS_HSTPIP.PRSTx) bit. This is
recommended before using a pipe upon hardware reset or when a USB bus reset has been sent. This resets:
the internal state machine of this pipe,
the receive and transmit bank FIFO counters,
all the registers of this pipe (UOTGHS_HSTPIPCFGx, UOTGHS_HSTPIPISRx, UOTGHS_HSTPIPIMRx),
except its configuration (UOTGHS_HSTPIPCFGx.ALLOC, UOTGHS_HSTPIPCFGx.PBK,
UOTGHS_HSTPIPCFGx.PSIZE, UOTGHS_HSTPIPCFGx.PTOKEN, UOTGHS_HSTPIPCFGx.PTYPE,
UOTGHS_HSTPIPCFGx.PEPNUM, UOTGHS_HSTPIPCFGx.INTFRQ) and its Data Toggle Sequence field
(UOTGHS_HSTPIPISRx.DTSEQ).
The pipe configuration remains active and the pipe is still enabled.
The pipe reset may be associated with a clear of the data toggle sequence. This can be achieved by setting the
Reset Data Toggle bit in the Pipe x Control register (UOTGHS_HSTPIPIMRx.RSTDT) (by writing a one to the
Reset Data Toggle Set bit in the Pipe x Control Set register (UOTGHS_HSTPIPIERx.RSTDTS)).
In the end, the user has to write a zero to the UOTGHS_HSTPIP.PRSTx bit to complete the reset operation and to
start using the FIFO.
39.5.3.6 Pipe Activation
The pipe is maintained inactive and reset (see Section 39.5.3.5 for more details) as long as it is disabled
(UOTGHS_HSTPIP.PENx is zero). The Data Toggle Sequence field (UOTGHS_HSTPIPISRx.DTSEQ) is also
reset.
The algorithm represented on Figure 39-23 on page 1079 must be followed in order to activate a pipe.
Figure 39-23. Pipe Activation Algorithm
As long as the pipe is not correctly configured (UOTGHS_HSTPIPISRx.CFGOK is zero), the controller cannot
send packets to the device through this pipe.
The UOTGHS_HSTPIPISRx.CFGOK bit is only set if the configured size and number of banks are correct as
compared to their maximal allowed values for the pipe (see Table 39-1 on page 1053) and to the maximal FIFO
size (i.e. the DPRAM size).
Pipe
Activation
UOTGHS_HSTPIPISRx.CFGOK == 1?
ERROR
Yes
Pipe Activated
Enable the pipe.
UOTGHS_HSTPIP.PENx = 1
Test if the pipe configuration is
correct.
UOTGHS_HSTPIPPCFGx
.INTFRQ
.PEPNUM
.PTYPE
.PTOKEN
.PSIZE
.PBK
.ALLOC
Configure the pipe:
- interrupt request frequency
- endpoint number
- type
- size
- number of banks
Allocate the configured DPRAM banks
No
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See Section 39.5.1.6 for more details about DPRAM management.
Once the pipe is correctly configured (UOTGHS_HSTPIPISRx.CFGOK is one), only the
UOTGHS_HSTPIPCFGx.PTOKEN and UOTGHS_HSTPIPCFGx.INTFRQ fields can be written by software.
UOTGHS_HSTPIPCFGx.INTFRQ is meaningless for non-interrupt pipes.
When starting an enumeration, the user gets the device descriptor by sending a GET_DESCRIPTOR USB
request. This descriptor contains the maximal packet size of the device default control endpoint
(bMaxPacketSize0) and the user re-configures the size of the default control pipe with this size parameter.
39.5.3.7 Address Setup
Once the device has answered the first host requests with default device address 0, the host assigns a new
address to the device. The host controller has to send a USB reset to the device and to send a SET_ADDRESS
(addr) SETUP request with the new address to be used by the device. Once this SETUP transaction is over, the
user writes the new address into the USB Host Address for Pipe x field in the USB Host Device Address register
(HSTADDR.HSTADDRPx). All following requests, on all pipes, will be performed using this new address.
When the host controller sends a USB reset, the HSTADDRPx field is reset by hardware and the following host
requests will be performed using default device address 0.
39.5.3.8 Remote Wake-up
The controller host mode enters the Suspend state when the UOTGHS_HSTCTRL.SOFE bit is written to zero. No
more “Start of Frame” is sent on the USB bus and the USB device enters the Suspend state 3 ms later.
The device awakes the host by sending an Upstream Resume (Remote Wake-Up feature). When the host
controller detects a non-idle state on the USB bus, it sets the Host Wake-Up interrupt (UOTGHS_HSTISR.HWUPI)
bit. If the non-idle bus state corresponds to an Upstream Resume (K state), the Upstream Resume Received
Interrupt (UOTGHS_HSTISR.RXRSMI) bit is set. The user has to generate a Downstream Resume within 1 ms
and for at least 20 ms by writing a one to the Send USB Resume (UOTGHS_HSTCTRL.RESUME) bit. It is
mandatory to write a one to UOTGHS_HSTCTRL.SOFE before writing a one to UOTGHS_HSTCTRL.RESUME to
enter the Ready state, else UOTGHS_HSTCTRL.RESUME will have no effect.
39.5.3.9 Management of Control Pipes
A control transaction is composed of three stages:
SETUP
Data (IN or OUT)
Status (OUT or IN)
The user has to change the pipe token according to each stage.
For the control pipe, and only for it, each token is assigned a specific initial data toggle sequence:
SETUP: Data0
IN: Data1
OUT: Data1
39.5.3.10 Management of IN Pipes
IN packets are sent by the USB device controller upon IN requests from the host. All data which acknowledges or
not the bank can be read when it is empty.
The pipe must be configured first.
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When the host requires data from the device, the user has to select beforehand the IN request mode with the IN
Request Mode bit in the Pipe x IN Request register (UOTGHS_HSTPIPINRQx.INMODE):
When UOTGHS_HSTPIPINRQx.INMODE is written to zero, the UOTGHS will perform (INRQ + 1) IN
requests before freezing the pipe.
When UOTGHS_HSTPIPINRQx.INMODE is written to one, the UOTGHS will perform IN requests endlessly
when the pipe is not frozen by the user.
The generation of IN requests starts when the pipe is unfrozen (the Pipe Freeze
(UOTGHS_HSTPIPIMRx.PFREEZE) field in UOTGHS_HSTPIPIMRx is zero).
The Received IN Data Interrupt (UOTGHS_HSTPIPISRx.RXINI) bit is set at the same time as the FIFO Control
(UOTGHS_HSTPIPIMRx.FIFOCON) bit when the current bank is full. This triggers a PEP_x interrupt if the
Received IN Data Interrupt Enable (UOTGHS_HSTPIPIMRx.RXINE) bit is one.
UOTGHS_HSTPIPISRx.RXINI shall be cleared by software (by writing a one to the Received IN Data Interrupt
Clear bit in the Host Pipe x Clear register (UOTGHS_HSTPIPIDRx.RXINIC)) to acknowledge the interrupt, which
has no effect on the pipe FIFO.
The user then reads from the FIFO and clears the UOTGHS_HSTPIPIMRx.FIFOCON bit (by writing a one to the
FIFO Control Clear (UOTGHS_HSTPIPIDRx.FIFOCONC) bit) to free the bank. If the IN pipe is composed of
multiple banks, this also switches to the next bank. The UOTGHS_HSTPIPISRx.RXINI and
UOTGHS_HSTPIPIMRx.FIFOCON bits are updated in accordance with the status of the next bank.
UOTGHS_HSTPIPISRx.RXINI shall always be cleared before clearing UOTGHS_HSTPIPIMRx.FIFOCON.
The Read-write Allowed (UOTGHS_HSTPIPISRx.RWALL) bit is set when the current bank is not empty, i.e., the
software can read further data from the FIFO.
Figure 39-24. Example of an IN Pipe with 1 Data Bank
Figure 39-25. Example of an IN Pipe with 2 Data Banks
IN DATA
(bank 0) ACK
UOTGHS_HSTPIPISRx.RXINI
UOTGHS_HSTPIPIMRx.FIFOCON
HW
IN DATA
(bank 0) ACK
HW
SW
SW
SW
read data from CPU
BANK 0
read data from CPU
BANK 0
IN DATA
(bank 0) ACK
HW
IN DATA
(bank 1) ACK
SW
SW
read data from CPU
BANK 0
HW
SW
read data from CPU
BANK 1
UOTGHS_HSTPIPISRx.RXINI
UOTGHS_HSTPIPIMRx.FIFOCON
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39.5.3.11 Management of OUT Pipes
OUT packets are sent by the host. All data which acknowledges or not the bank can be written when it is full.
The pipe must be configured and unfrozen first.
The Transmitted OUT Data Interrupt (UOTGHS_HSTPIPISRx.TXOUTI) bit is set at the same time as
UOTGHS_HSTPIPIMRx.FIFOCON when the current bank is free. This triggers a PEP_x interrupt if the
Transmitted OUT Data Interrupt Enable (UOTGHS_HSTPIPIMRx.TXOUTE) bit is one.
UOTGHS_HSTPIPISRx.TXOUTI shall be cleared by software (by writing a one to the Transmitted OUT Data
Interrupt Clear (UOTGHS_HSTPIPIDRx.TXOUTIC) bit) to acknowledge the interrupt, which has no effect on the
pipe FIFO.
The user then writes into the FIFO and clears the UOTGHS_HSTPIPIDRx.FIFOCON bit to allow the UOTGHS to
send the data. If the OUT pipe is composed of multiple banks, this also switches to the next bank. The
UOTGHS_HSTPIPISRx.TXOUTI and UOTGHS_HSTPIPIMRx.FIFOCON bits are updated in accordance with the
status of the next bank.
UOTGHS_HSTPIPISRx.TXOUTI shall always be cleared before clearing UOTGHS_HSTPIPIMRx.FIFOCON.
The UOTGHS_HSTPIPISRx.RWALL bit is set when the current bank is not full, i.e., the software can write further
data into the FIFO.
Notes: 1. If the user decides to switch to the Suspend state (by writing a zero to the UOTGHS_HSTCTRL.SOFE bit) while a
bank is ready to be sent, the UOTGHS automatically exits this state and the bank is sent.
2. In High-Speed operating mode, the host controller automatically manages the PING protocol to maximize the
USB bandwidth. The user can tune the PING protocol by handling the Ping Enable (PINGEN) bit and the bInterval
Parameter for the Bulk-Out/Ping Transaction (BINTERVALL) field in UOTGHS_HSTPIPCFGx. See the Section
39.6.3.13 for more details.
Figure 39-26. Example of an OUT Pipe with one Data Bank
Figure 39-27. Example of an OUT Pipe with two Data Banks and no Bank Switching Delay
OUT DATA
(bank 0) ACK
HW
write data to CPU
BANK 0 SW
SW SW
SW
OUT
write data to CPU
BANK 0
UOTGHS_HSTPIPISRx.TXOUTI
UOTGHS_HSTPIPIMRx.FIFOCON
OUT DATA
(bank 0) ACK
write data to CPU
BANK 0 SW
SW SW
SW
write data to CPU
BANK 1
SW
HW
write data to CPU
BANK0
OUT DATA
(bank 1) ACK
UOTGHS_HSTPIPISRx.TXOUTI
UOTGHS_HSTPIPIMRx.FIFOCON
ACK E
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Figure 39-28. Example of an OUT Pipe with two Data Banks and a Bank Switching Delay
39.5.3.12 CRC Error
This error exists only for isochronous IN pipes. It sets the CRC Error Interrupt (UOTGHS_HSTPIPISRx.CRCERRI)
bit, which triggers a PEP_x interrupt if then the CRC Error Interrupt Enable (UOTGHS_HSTPIPIMRx.CRCERRE)
bit is one.
A CRC error can occur during IN stage if the UOTGHS detects a corrupted received packet. The IN packet is
stored in the bank as if no CRC error had occurred (UOTGHS_HSTPIPISRx.RXINI is set).
39.5.3.13 Interrupts
See the structure of the USB host interrupt system on Figure 39-6 on page 1059.
There are two kinds of host interrupts: processing, i.e. their generation is part of the normal processing, and
exception, i.e. errors (not related to CPU exceptions).
Global interrupts
The processing host global interrupts are:
The Device Connection Interrupt (UOTGHS_HSTISR.DCONNI)
The Device Disconnection Interrupt (UOTGHS_HSTISR.DDISCI)
The USB Reset Sent Interrupt (UOTGHS_HSTISR.RSTI)
The Downstream Resume Sent Interrupt (UOTGHS_HSTISR.RSMEDI)
The Upstream Resume Received Interrupt (UOTGHS_HSTISR.RXRSMI)
The Host Start of Frame Interrupt (UOTGHS_HSTISR.HSOFI)
The Host Wake-Up Interrupt (UOTGHS_HSTISR.HWUPI)
The Pipe x Interrupt (UOTGHS_HSTISR.PEP_x)
The DMA Channel x Interrupt (UOTGHS_HSTISR.DMAxINT)
There is no exception host global interrupt.
Pipe interrupts
The processing host pipe interrupts are:
The Received IN Data Interrupt (UOTGHS_HSTPIPISRx.RXINI)
The Transmitted OUT Data Interrupt (UOTGHS_HSTPIPISRx.TXOUTI)
The Transmitted SETUP Interrupt (UOTGHS_HSTPIPISRx.TXSTPI)
The Short Packet Interrupt (UOTGHS_HSTPIPISRx.SHORTPACKETI)
The Number of Busy Banks (UOTGHS_HSTPIPISRx.NBUSYBK) interrupt
OUT DATA
(bank 0) ACK
write data to CPU
BANK 0 SW
SW SW
SW
OUT DATA
(bank 1) ACK
write data to CPU
BANK 1
SW
HW
write data to CPU
BANK0
UOTGHS_HSTPIPISRx.TXOUTI
UOTGHS_HSTPIPIMRx.FIFOCON
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The exception host pipe interrupts are:
The Underflow Interrupt (UOTGHS_HSTPIPISRx.UNDERFI)
The Pipe Error Interrupt (UOTGHS_HSTPIPISRx.PERRI)
The NAKed Interrupt (UOTGHS_HSTPIPISRx.NAKEDI)
The Overflow Interrupt (UOTGHS_HSTPIPISRx.OVERFI)
The Received STALLed Interrupt (UOTGHS_HSTPIPISRx.RXSTALLDI)
The CRC Error Interrupt (UOTGHS_HSTPIPISRx.CRCERRI)
DMA interrupts
The processing host DMA interrupts are:
The End of USB Transfer Status (UOTGHS_HSTDMASTATUSx.END_TR_ST) interrupt
The End of Channel Buffer Status (UOTGHS_HSTDMASTATUSx.END_BF_ST) interrupt
The Descriptor Loaded Status (UOTGHS_HSTDMASTATUSx.DESC_LDST) interrupt
There is no exception host DMA interrupt.
39.5.4 USB DMA Operation
USB packets of any length may be transferred when required by the UOTGHS. These transfers always feature
sequential addressing. These two characteristics mean that in case of high UOTGHS throughput, both AHB ports
will benefit from “incrementing burst of unspecified length” since the average access latency of AHB slaves can
then be reduced.
The DMA uses word “incrementing burst of unspecified length” of up to 256 beats for both data transfers and
channel descriptor loading. A burst may last on the AHB busses for the duration of a whole USB packet transfer,
unless otherwise broken by the AHB arbitration or the AHB 1 kbyte boundary crossing.
Packet data AHB bursts may be locked on a DMA buffer basis for drastic overall AHB bus bandwidth performance
boost with paged memories. This is because these memory row (or bank) changes, which are very clock-cycle
consuming, will then likely not occur or occur once instead of dozens of times during a single big USB packet DMA
transfer in case other AHB masters address the memory. This means up to 128 words single cycle unbroken AHB
bursts for bulk pipes/endpoints and 256 words single cycle unbroken bursts for isochronous pipes/endpoints. This
maximal burst length is then controlled by the lowest programmed USB pipe/endpoint size
(UOTGHS_HSTPIPCFGx.PSIZE / UOTGHS_DEVEPTCFGx.EPSIZE) and the Buffer Byte Length
(UOTGHS_HSTDMACONTROLx.BUFF_LENGTH / UOTGHS_DEVDMACONTROLx.BUFF_LENGTH) field.
The UOTGHS average throughput may be up to nearly 480 Mbps. Its average access latency decreases as burst
length increases due to the zero wait-state side effect of unchanged pipe/endpoint. Word access allows reducing
the AHB bandwidth required for the USB by four, as compared to native byte access. If at least 0 wait-state word
burst capability is also provided by the other DMA AHB bus slaves, each of both DMA AHB busses need less than
60% bandwidth allocation for full USB bandwidth usage at 33 MHz, and less than 30% at 66 MHz.
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Figure 39-29. Example of DMA Chained List
39.5.5 USB DMA Channel Transfer Descriptor
The DMA channel transfer descriptor is loaded from the memory. Be careful with the alignment of this buffer. The
structure of the DMA channel transfer descriptor is defined by three parameters as described below:
Offset 0:
The address must be aligned: 0xXXXX0
Next Descriptor Address Register: UOTGHS_xxxDMANXTDSCx
Offset 4:
The address must be aligned: 0xXXXX4
DMA Channelx Address Register: UOTGHS_xxxDMAADDRESSx
Offset 8:
The address must be aligned: 0xXXXX8
DMA Channelx Control Register: UOTGHS_xxxDMACONTROLx
To use the DMA channel transfer descriptor, fill the structures with the correct value (as described in the following
pages). Then write directly in UOTGHS_xxxDMANXTDSCx the address of the descriptor to be used first.
Then write 1 in UOTGHS_xxxDMACONTROLx.LDNXT_DSC bit (load next channel transfer descriptor). The
descriptor is automatically loaded upon pipe x / endpoint x request for packet transfer.
Data Buffer 1
Data Buffer 2
Data Buffer 3
Memory Area
Transfer Descriptor
Next Descriptor Address
AHB Address
Control
Transfer Descriptor
Transfer Descriptor
USB DMA Channel X Registers
(Current Transfer Descriptor)
Next Descriptor Address
AHB Address
Control
NULL
Status
Next Descriptor Address
AHB Address
Control Next Descriptor Address
AHB Address
Control
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39.6 USB On-The-Go Interface (UOTGHS) User Interface
Table 39-5. Register Mapping
Offset Register
Name
Access Reset
0x0000 Device General Control Register
UOTGHS_DEVCTRL
Read-write 0x00000100
0x0004 Device Global Interrupt Status Register
UOTGHS_DEVISR
Read-only 0x00000000
0x0008 Device Global Interrupt Clear Register
UOTGHS_DEVICR
Write-only
0x000C Device Global Interrupt Set Register
UOTGHS_DEVIFR
Write-only
0x0010 Device Global Interrupt Mask Register
UOTGHS_DEVIMR
Read-only 0x00000000
0x0014 Device Global Interrupt Disable Register
UOTGHS_DEVIDR
Write-only
0x0018 Device Global Interrupt Enable Register
UOTGHS_DEVIER
Write-only
0x001C Device Endpoint Register
UOTGHS_DEVEPT
Read-write 0x00000000
0x0020 Device Frame Number Register
UOTGHS_DEVFNUM
Read-only 0x00000000
0x0100 + (n * 0x04) + 0x00 Device Endpoint Configuration Register
UOTGHS_DEVEPTCFG
Read-write 0x00002000
0x0100 + (n * 0x04) + 0x30 Device Endpoint Status Register
UOTGHS_DEVEPTISR
Read-only 0x00000100
0x0100 + (n * 0x04) + 0x60 Device Endpoint Clear Register
UOTGHS_DEVEPTICR
Write-only
0x0100 + (n * 0x04) + 0x90 Device Endpoint Set Register
UOTGHS_DEVEPTIFR
Write-only
0x0100 + (n * 0x04) + 0x0C0 Device Endpoint Mask Register
UOTGHS_DEVEPTIMR
Read-only 0x00000000
0x0100 + (n * 0x04) + 0x0F0 Device Endpoint Enable Register
UOTGHS_DEVEPTIER
Write-only
0x0100 + (n * 0x04) + 0x0120 Device Endpoint Disable Register
UOTGHS_DEVEPTIDR
Write-only
0x0300 + (n * 0x10)+0x00 Device DMA Channel Next Descriptor
Address Register
UOTGHS_DEVDMANXTDSC
Read-write 0x00000000
0x0300 + (n * 0x10)+0x04 Device DMA Channel Address Register
UOTGHS_DEVDMAADDRESS
Read-write 0x00000000
0x0300 + (n * 0x10)+0x08 Device DMA Channel Control Register
UOTGHS_DEVDMACONTROL
Read-write 0x00000000
0x0300 + (n * 0x10)+0x0C Device DMA Channel Status Register
UOTGHS_DEVDMASTATUS
Read-write 0x00000000
0x0400 Host General Control Register
UOTGHS_HSTCTRL
Read-write 0x00000000
0x0404 Host Global Interrupt Status Register
UOTGHS_HSTISR
Read-only 0x00000000
0x0408 Host Global Interrupt Clear Register
UOTGHS_HSTICR
Write-only
0x040C Host Global Interrupt Set Register
UOTGHS_HSTIFR
Write-only
0x0410 Host Global Interrupt Mask Register
UOTGHS_HSTIMR
Read-only 0x00000000
0x0414 Host Global Interrupt Disable Register
UOTGHS_HSTIDR
Write-only
0x0418 Host Global Interrupt Enable Register
UOTGHS_HSTIER
Write-only
0x0041C Host Pipe Register
UOTGHS_HSTPIP
Read-write 0x00000000
0x0420 Host Frame Number Register
UOTGHS_HSTFNUM
Read-write 0x00000000
0x0424 Host Address 1 Register
UOTGHS_HSTADDR1
Read-write 0x00000000
0x0428 Host Address 2 Register
UOTGHS_HSTADDR2
Read-write 0x00000000
0x042C Host Address 3 Register
UOTGHS_HSTADDR3
Read-write 0x00000000
0x0500 + (n * 0x04) + 0x00 Host Pipe Configuration Register
UOTGHS_HSTPIPCFG
Read-write 0x00000000
0x0500 + (n * 0x04) + 0x30 Host Pipe Status Register
UOTGHS_HSTPIPISR
Read-only 0x00000000
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0x0500 + (n * 0x04) + 0x60 Host Pipe Clear Register
UOTGHS_HSTPIPICR
Write-only
0x0500 + (n * 0x04) + 0x90 Host Pipe Set Register
UOTGHS_HSTPIPIFR
Write-only
0x0500 + (n * 0x04) + 0xC0 Host Pipe Mask Register
UOTGHS_HSTPIPIMR
Read-only 0x00000000
0x0500 + (n * 0x04) + 0xF0 Host Pipe Enable Register
UOTGHS_HSTPIPIER
Write-only
0x0500+ (n * 0x04) + 0x120 Host Pipe Disable Register
UOTGHS_HSTPIPIDR
Write-only
0x0500+ (n * 0x04) + 0x150 Host Pipe IN Request Register
UOTGHS_HSTPIPINRQ
Read-write 0x00000000
0x0500 + (n * 0x04) + 0x180 Host Pipe Error Register
UOTGHS_HSTPIPERR
Read-write 0x00000000
0x0700 + (n * 0x10) + 0x00 Host DMA Channel Next Descriptor
Address Register
UOTGHS_HSTDMANXTDSC
Read-write 0x00000000
0x0700 + (n * 0x10) + 0x04 Host DMA Channel Address Register
UOTGHS_HSTDMAADDRESS
Read-write 0x00000000
0x0700 + (n * 0x10) + 0x08 Host DMA Channel Control Register
UOTGHS_HSTDMACONTROL
Read-write 0x00000000
0x0700 + (n * 0x10) + 0x0C Host DMA Channel Status Register
UOTGHS_HSTDMASTATUS
Read-write 0x00000000
0x0800 General Control Register
UOTGHS_CTRL
Read-write 0x03004000
0x0804 General Status Register
UOTGHS_SR
Read-only 0x00000400
0x0808 General Status Clear Register
UOTGHS_SCR
Write-only
0x080C General Status Set Register
UOTGHS_SFR
Write-only
0x082C General Finite State Machine Register
UOTGHS_FSM
Read-only 0x00000009
Table 39-5. Register Mapping (Continued)
Offset Register
Name
Access Reset
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39.6.1 USB General Registers
39.6.1.1 General Control Register
Name: UOTGHS_CTRL
Address: 0x400AC800
Access: Read-write
• UIMOD: UOTGHS Mode
This bit has no effect when UIDE is one (UOTGID input pin activated).
0 (Host): The module is in USB host mode.
1 (Device): The module is in USB device mode.
This bit can be written even if USBE is zero or FRZCLK is one. Disabling the UOTGHS (by writing a zero to the USBE bit)
does not reset this bit.
• UIDE: UOTGID Pin Enable
0 (UIMOD): The USB mode (device/host) is selected from the UIMOD bit.
1 (UOTGID): The USB mode (device/host) is selected from the UOTGID input pin.
This bit can be written even if USBE is zero or FRZCLK is one. Disabling the UOTGHS (by writing a zero to the USBE bit)
does not reset this bit.
• UNLOCK: Timer Access Unlock
0: The TIMPAGE and TIMVALUE fields are locked.
1: The TIMPAGE and TIMVALUE fields are unlocked.
The TIMPAGE and TIMVALUE fields can always be read, whatever the value of UNLOCK.
• TIMPAGE: Timer Page
This field contains the page value to access a special timer register.
• TIMVALUE: Timer Value
This field selects the timer value that is written to the special time register selected by TIMPAGE. See Section 39.5.1.8 for
details.
• USBE: UOTGHS Enable
Writing a zero to this bit will reset the UOTGHS, disable the USB transceiver, and disable the UOTGHS clock inputs.
Unless explicitly stated, all registers will then become read-only and will be reset.
0: The UOTGHS is disabled.
1: The UOTGHS is enabled.
This bit can be written even if FRZCLK is one.
31 30 29 28 27 26 25 24
––––––UIMODUIDE
23 22 21 20 19 18 17 16
– UNLOCK TIMPAGE – – TIMVALUE
15 14 13 12 11 10 9 8
USBE FRZCLK VBUSPO OTGPADE HNPREQ SRPREQ SRPSEL VBUSHWC
76543210
STOE HNPERRE ROLEEXE BCERRE VBERRE SRPE VBUSTE IDTE
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• FRZCLK: Freeze USB Clock
0: The clock inputs are enabled.
1: The clock inputs are disabled (the resume detection is still active).This reduces the power consumption. Unless explicitly
stated, all registers then become read-only.
This bit can be written even if USBE is zero. Disabling the UOTGHS (by writing a zero to the USBE bit) does not reset this
bit, but this freezes the clock inputs whatever its value.
• VBUSPO: VBus Polarity Off
0: The UOTGVBOF output signal is in its default mode (active high).
1: The UOTGVBOF output signal is inverted (active low).
To be generic. May be useful to control an external VBus power module.
This bit can be written even if USBE is zero or FRZCLK is one. Disabling the UOTGHS (by writing a zero to the USBE bit)
does not reset this bit.
• OTGPADE: OTG Pad Enable
0: The OTG pad is disabled.
1: The OTG pad is enabled.
This bit can be written even if USBE is zero or FRZCLK is one. Disabling the UOTGHS (by writing a zero to the USBE bit)
does not reset this bit.
• HNPREQ: HNP Request
When the controller is in device mode:
•Writing a one to this bit will initiate an HNP (Host Negotiation Protocol).
•Writing a zero to this bit has no effect.
This bit is cleared when the controller has initiated an HNP.
When the controller is in host mode:
•Writing a one to this bit will accept an HNP.
•Writing a zero to this bit will reject an HNP.
• SRPREQ: SRP Request
Writing a one to this bit will initiate an SRP when the controller is in device mode.
Writing a zero to this bit has no effect.
This bit is cleared when the controller has initiated an SRP.
• SRPSEL: SRP Selection
0: Data line pulsing is selected as an SRP method.
1: VBus pulsing is selected as an SRP method.
• VBUSHWC: VBus Hardware Control
0: The hardware control over the UOTGVBOF output pin is enabled. The UOTGHS resets the UOTGVBOF output pin
when a VBUS problem occurs.
1: The hardware control over the UOTGVBOF output pin is disabled.
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• STOE: Suspend Time-Out Interrupt Enable
0: The Suspend Time-Out Interrupt (UOTGHS_SR.STOI) is disabled.
1: The Suspend Time-Out Interrupt (UOTGHS_SR.STOI) is enabled.
• HNPERRE: HNP Error Interrupt Enable
0: The HNP Error Interrupt (UOTGHS_SR.HNPERRI) is disabled.
1: The HNP Error Interrupt (UOTGHS_SR.HNPERRI) is enabled.
• ROLEEXE: Role Exchange Interrupt Enable
0: The Role Exchange Interrupt (UOTGHS_SR.ROLEEXI) is disabled.
1: The Role Exchange Interrupt (UOTGHS_SR.ROLEEXI) is enabled.
• BCERRE: B-Connection Error Interrupt Enable
0: The B-Connection Error Interrupt (UOTGHS_SR.BCERRI) is disabled.
1: The B-Connection Error Interrupt (UOTGHS_SR.BCERRI) is enabled.
• VBERRE: VBus Error Interrupt Enable
0: The VBus Error Interrupt (UOTGHS_SR.VBERRI) is disabled.
1: The VBus Error Interrupt (UOTGHS_SR.VBERRI) is enabled.
• SRPE: SRP Interrupt Enable
0: The SRP Interrupt (UOTGHS_SR.SRPI) is disabled.
1: The SRP Interrupt (UOTGHS_SR.SRPI) is enabled.
• VBUSTE: VBus Transition Interrupt Enable
0: The VBus Transition Interrupt (UOTGHS_SR.VBUSTI) is disabled.
1: The VBus Transition Interrupt (UOTGHS_SR.VBUSTI) is enabled.
• IDTE: ID Transition Interrupt Enable
0: The ID Transition interrupt (UOTGHS_SR.IDTI) is disabled.
1: The ID Transition interrupt (UOTGHS_SR.IDTI) is enabled.
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39.6.1.2 General Status Register
Name: UOTGHS_SR
Address: 0x400AC804
Access: Read-only
• CLKUSABLE: UTMI Clock Usable
This bit is set when the UTMI 30 MHz is usable.
This bit is cleared when the UTMI 30 MHz is not usable.
• SPEED: Speed Status
This field is set according to the controller speed mode. This field shall only be used in device mode.
• VBUS: VBus Level
This bit is set when the VBus line level is high, even if UOTGHS_CTRL.USBE is zero.
This bit is cleared when the VBus line level is low, even if UOTGHS_CTRL.USBE is zero.
This bit can be used in device mode to monitor the USB bus connection state of the application.
• ID: UOTGID Pin State
This bit is cleared when the UOTGID level is low, even if UOTGHS_CTRL.USBE is zero.
This bit is set when the UOTGID level is high, event if UOTGHS_CTRL.USBE is zero.
• VBUSRQ: VBus Request
This bit is set when the UOTGHS_SFR.VBUSRQS bit is written to one.
This bit is cleared when the UOTGHS_SCR.VBUSRQC bit is written to one or when a VBus error occurs and
UOTGHS_CTRL.VBUSHWC is zero.
0: The UOTGVBOF output pin is driven low to disable the VBUS power supply generation.
1: The UOTGVBOF output pin is driven high to enable the VBUS power supply generation.
This bit shall only be used in host mode.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– CLKUSABLE SPEED VBUS ID VBUSRQ –
76543210
STOI HNPERRI ROLEEXI BCERRI VBERRI SRPI VBUSTI IDTI
Value Name Description
0 FULL_SPEED Full-Speed mode
2 LOW_SPEED Low-Speed mode
1 HIGH_SPEED High-Speed mode
3 Reserved
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• STOI: Suspend Time-Out Interrupt
This bit is set when a time-out error (more than 200ms) has been detected after a suspend. This triggers a USB interrupt if
UOTGHS_CTRL.STOE is one.
This bit is cleared when the UOTGHS_SCR.STOIC bit is written to one.
This bit shall only be used in host mode.
• HNPERRI: HNP Error Interrupt
This bit is set when an error has been detected during a HNP negotiation. This triggers a USB interrupt if
UOTGHS_CTRL.HNPERRE is one.
This bit is cleared when the UOTGHS_SCR.HNPERRIC bit is written to one.
This bit shall only be used in device mode.
• ROLEEXI: Role Exchange Interrupt
This bit is set when the UOTGHS has successfully switched its mode because of an HNP negotiation (host to device or
device to host). This triggers a USB interrupt if UOTGHS_CTRL.ROLEEXE is one.
This bit is cleared when the UOTGHS_SCR.ROLEEXIC bit is written to one.
• BCERRI: B-Connection Error Interrupt
This bit is set when an error occurs during the B-connection. This triggers a USB interrupt if UOTGHS_CTRL.BCERRE is
one.
This bit is cleared when the UOTGHS_SCR.BCERRIC bit is written to one.
This bit shall only be used in host mode.
• VBERRI: VBus Error Interrupt
This bit is set when a VBus drop has been detected. This triggers a USB interrupt if UOTGHS_CTRL.VBERRE is one.
This bit is cleared when the UOTGHS_SCR.VBERRIC bit is written to one.
This bit shall only be used in host mode.
If a VBus problem occurs, then the VBERRI interrupt is generated even if the UOTGHS does not go to an error state
because UOTGHS_CTRL.VBUSHWC is one.
• SRPI: SRP Interrupt
This bit is set when an SRP has been detected. This triggers a USB interrupt if UOTGHS_CTRL.SRPE is one.
This bit is cleared when the UOTGHS_SCR.SRPIC bit is written to one.
This bit shall only be used in host mode.
• VBUSTI: VBus Transition Interrupt
This bit is set when a transition (high to low, low to high) has been detected on the VBUS pad. This triggers a USB interrupt
if UOTGHS_CTRL.VBUSTE is one.
This bit is cleared when the UOTGHS_SCR.VBUSTIC bit is written to one.
This interrupt is generated even if the clock is frozen by the UOTGHS_CTRL.FRZCLK bit.
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• IDTI: ID Transition Interrupt
This bit is set when a transition (high to low, low to high) has been detected on the UOTGID input pin. This triggers a USB
interrupt if UOTGHS_CTRL.IDTE is one.
This bit is cleared when the UOTGHS_SCR.IDTIC bit is written to one.
This interrupt is generated even if the clock is frozen by the UOTGHS_CTRL.FRZCLK bit.
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39.6.1.3 General Status Clear Register
Name: UOTGHS_SCR
Address: 0x400AC808
Access: Write-only
• VBUSRQC: VBus Request Clear
Writing a one will clear VBUSRQ bit in UOTGHS_SR.
Writing a zero to this bit has no effect.
This bit always read as zero.
• STOIC: Suspend Time-Out Interrupt Clear
Writing a one will clear STOI bit in UOTGHS_SR.
Writing a zero to this bit has no effect.
This bit always read as zero.
• HNPERRIC: HNP Error Interrupt Clear
Writing a one twill clear HNPERRI bit in UOTGHS_SR.
Writing a zero to this bit has no effect.
This bit always read as zero.
• ROLEEXIC: Role Exchange Interrupt Clear
Writing a one twill clear ROLEEXI bit in UOTGHS_SR.
Writing a zero to this bit has no effect.
This bit always read as zero.
• BCERRIC: B-Connection Error Interrupt Clear
Writing a one will clear BCERRI bit in UOTGHS_SR.
Writing a zero to this bit has no effect.
This bit always read as zero.
• VBERRIC: VBus Error Interrupt Clear
Writing a one will clear VBERRI bit in UOTGHS_SR.
Writing a zero to this bit has no effect.
This bit always read as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––VBUSRQC–
76543210
STOIC HNPERRIC ROLEEXIC BCERRIC VBERRIC SRPIC VBUSTIC IDTIC
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• SRPIC: SRP Interrupt Clear
Writing a one will clear SRPI bit in UOTGHS_SR.
Writing a zero to this bit has no effect.
This bit always read as zero.
• VBUSTIC: VBus Transition Interrupt Clear
Writing a one will clear VBUSTI bit in UOTGHS_SR.
Writing a zero to this bit has no effect.
This bit always read as zero.
• IDTIC: ID Transition Interrupt Clear
Writing a one will clear IDTI bit in UOTGHS_SR.
Writing a zero to this bit has no effect.
This bit always read as zero.
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39.6.1.4 General Status Set Register
Name: UOTGHS_SFR
Address: 0x400AC80C
Access: Write-only
• VBUSRQS: VBus Request Set
Writing a one will set VBUSRQ bit in UOTGHS_SR.
Writing a zero to this bit has no effect.
This bit always read as zero.
• STOIS: Suspend Time-Out Interrupt Set
Writing a one will set STOI bit in UOTGHS_SR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always read as zero.
• HNPERRIS: HNP Error Interrupt Set
Writing a one will set HNPERRI bit in UOTGHS_SR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always read as zero.
• ROLEEXIS: Role Exchange Interrupt Set
Writing a one will set ROLEEXI bit in UOTGHS_SR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always read as zero.
• BCERRIS: B-Connection Error Interrupt Set
Writing a one will set BCERRI bit in UOTGHS_SR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always read as zero.
• VBERRIS: VBus Error Interrupt Set
Writing a one will set VBERRI bit in UOTGHS_SR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always read as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––VBUSRQS–
76543210
STOIS HNPERRIS ROLEEXIS BCERRIS VBERRIS SRPIS VBUSTIS IDTIS
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• SRPIS: SRP Interrupt Set
Writing a one will set SRPI bit in UOTGHS_SR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always read as zero.
• VBUSTIS: VBus Transition Interrupt Set
Writing a one will set VBUSTI bit in UOTGHS_SR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always read as zero.
• IDTIS: ID Transition Interrupt Set
Writing a one will set IDTI bit in UOTGHS_SR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always read as zero.
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39.6.1.5 General Finite State Machine Register
Name: UOTGHS_FSM
Address: 0x400AC82C
Access: Read-only
•DRDSTATE
This field indicates the state of the UOTGHS.
Refer to the OTG specification for more details.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––– DRDSTATE
Value Name Description
0 A_IDLESTATE This is the start state for A-devices (when the ID pin is 0)
1 A_WAIT_VRISE In this state, the A-device waits for the voltage on VBus to rise above the A-device VBus
Valid threshold (4.4 V).
2 A_WAIT_BCON In this state, the A-device waits for the B-device to signal a connection.
3 A_HOST In this state, the A-device that operates in Host mode is operational.
4 A_SUSPEND The A-device operating as a host is in the suspend mode.
5 A_PERIPHERAL The A-device operates as a peripheral.
6 A_WAIT_VFALL In this state, the A-device waits for the voltage on VBus to drop below the A-device
Session Valid threshold (1.4 V).
7 A_VBUS_ERR In this state, the A-device waits for recovery of the over-current condition that caused it
to enter this state.
8 A_WAIT_DISCHARGE In this state, the A-device waits for the data USB line to discharge (100 us).
9 B_IDLE This is the start state for B-device (when the ID pin is 1).
10 B_PERIPHERAL In this state, the B-device acts as the peripheral.
11 B_WAIT_BEGIN_HNP In this state, the B-device is in suspend mode and waits until 3 ms before initiating the
HNP protocol if requested.
12 B_WAIT_DISCHARGE In this state, the B-device waits for the data USB line to discharge (100 us) before
becoming Host.
13 B_WAIT_ACON In this state, the B-device waits for the A-device to signal a connect before becoming B-
Host.
14 B_HOST In this state, the B-device acts as the Host.
15 B_SRP_INIT In this state, the B-device attempts to start a session using the SRP protocol.
1099
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2 USB Device Registers
39.6.2.1 Device General Control Register
Name: UOTGHS_DEVCTRL
Address: 0x400AC000
Access: Read-write
• OPMODE2: Specific Operational mode
0: The UTMI transceiver is in normal operation mode.
1: The UTMI transceiver is in the «disable bit stuffing and NRZI encoding» operational mode for test purpose.
• TSTPCKT: Test packet mode
0: The UTMI transceiver is in normal operation mode.
1: The UTMI transceiver generates test packets for test purpose.
• TSTK: Test mode K
0: The UTMI transceiver is in normal operation mode.
1: The UTMI transceiver generates high-speed K state for test purpose.
• TSTJ: Test mode J
0: The UTMI transceiver is in normal operation mode.
1: The UTMI transceiver generates high-speed J state for test purpose.
• LS: Low-Speed Mode Force
0: The full-speed mode is active.
1: The low-speed mode is active.
This bit can be written even if UOTGHS_CTRL.USBE is zero or UOTGHS_CTRL.FRZCLK is one. Disabling the UOTGHS
(by writing a zero to the UOTGHS_CTRL.USBE bit) does not reset this bit.
• SPDCONF: Mode Configuration
This field contains the peripheral speed:
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––––OPMODE2
15 14 13 12 11 10 9 8
TSTPCKT TSTK TSTJ LS SPDCONF RMWKUP DETACH
76543210
ADDEN UADD
Value Name Description
0NORMAL
The peripheral starts in full-speed mode and performs a high-speed reset to switch to the
high-speed mode if the host is high-speed capable.
1 LOW_POWER For a better consumption, if high-speed is not needed.
2 HIGH_SPEED Forced high speed.
3 FORCED_FS The peripheral remains in full-speed mode whatever the host speed capability.
AtmeL
SAM3X / SAM3A [DATASHEET]
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1100
• RMWKUP: Remote Wake-Up
Writing a one to this bit will send an upstream resume to the host for a remote wake-up.
Writing a zero to this bit has no effect.
This bit is cleared when the UOTGHS receives a USB reset or once the upstream resume has been sent.
• DETACH: Detach
Writing a one to this bit will physically detach the device (disconnect internal pull-up resistor from D+ and D-).
Writing a zero to this bit will reconnect the device.
• ADDEN: Address Enable
Writing a one to this bit will activate the UADD field (USB address).
Writing a zero to this bit has no effect.
This bit is cleared when a USB reset is received.
• UADD: USB Address
This field contains the device address.
This field is cleared when a USB reset is received.
1101
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.2 Device Global Interrupt Status Register
Name: UOTGHS_DEVISR
Address: 0x400AC004
Access: Read-only
• DMA_x: DMA Channel x Interrupt
This bit is set when an interrupt is triggered by the DMA channel x. This triggers a USB interrupt if DMA_x is one.
This bit is cleared when the UOTGHS_DEVDMASTATUSx interrupt source is cleared.
• PEP_x: Endpoint x Interrupt
This bit is set when an interrupt is triggered by the endpoint x (UOTGHS_DEVEPTISRx, UOTGHS_DEVEPTIMRx). This
triggers a USB interrupt if UOTGHS_DEVIMR.PEP_x is one.
This bit is cleared when the interrupt source is serviced.
• UPRSM: Upstream Resume Interrupt
This bit is set when the UOTGHS sends a resume signal called “Upstream Resume”. This triggers a USB interrupt if
UOTGHS_DEVIMR.UPRSME is one.
This bit is cleared when the UOTGHS_DEVICR.UPRSMC bit is written to one to acknowledge the interrupt (USB clock
inputs must be enabled before).
• EORSM: End of Resume Interrupt
This bit is set when the UOTGHS detects a valid “End of Resume” signal initiated by the host. This triggers a USB interrupt
if UOTGHS_DEVIMR.EORSME is one.
This bit is cleared when the UOTGHS_DEVICR.EORSMC bit is written to one to acknowledge the interrupt.
• WAKEUP: Wake-Up Interrupt
This bit is set when the UOTGHS is reactivated by a filtered non-idle signal from the lines (not by an upstream resume).
This triggers an interrupt if UOTGHS_DEVIMR.WAKEUPE is one.
This bit is cleared when the UOTGHS_DEVICR.WAKEUPC bit is written to one to acknowledge the interrupt (USB clock
inputs must be enabled before).
This bit is cleared when the Suspend (SUSP) interrupt bit is set.
This interrupt is generated even if the clock is frozen by the UOTGHS_CTRL.FRZCLK bit.
• EORST: End of Reset Interrupt
This bit is set when a USB “End of Reset” has been detected. This triggers a USB interrupt if UOTGHS_DEVIMR.EORSTE
is one.
This bit is cleared when the UOTGHS_DEVICR.EORSTC bit is written to one to acknowledge the interrupt.
31 30 29 28 27 26 25 24
– DMA_6 DMA_5 DMA_4 DMA_3 DMA_2 DMA_1 –
23 22 21 20 19 18 17 16
– – PEP_9 PEP_8 PEP_7 PEP_6 PEP_5 PEP_4
15 14 13 12 11 10 9 8
PEP_3PEP_2PEP_1PEP_0––––
76543210
– UPRSM EORSM WAKEUP EORST SOF MSOF SUSP
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1102
• SOF: Start of Frame Interrupt
This bit is set when a USB “Start of Frame” PID (SOF) has been detected (every 1 ms). This triggers a USB interrupt if
SOFE is one. The FNUM field is updated. In High-speed mode, the MFNUM field is cleared.
This bit is cleared when the UOTGHS_DEVICR.SOFC bit is written to one to acknowledge the interrupt.
• MSOF: Micro Start of Frame Interrupt
This bit is set in High-speed mode when a USB “Micro Start of Frame” PID (SOF) has been detected (every 125 us). This
triggers a USB interrupt if MSOFE is one. The MFNUM field is updated. The FNUM field is unchanged.
This bit is cleared when the UOTGHS_DEVICR.MSOFC bit is written to one to acknowledge the interrupt.
• SUSP: Suspend Interrupt
This bit is set when a USB “Suspend” idle bus state has been detected for 3 frame periods (J state for 3 ms). This triggers
a USB interrupt if UOTGHS_DEVIMR.SUSPE is one.
This bit is cleared when the UOTGHS_DEVICR.SUSPC bit is written to one to acknowledge the interrupt.
This bit is cleared when the Wake-Up (WAKEUP) interrupt bit is set.
1103
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.3 Device Global Interrupt Clear Register
Name: UOTGHS_DEVICR
Address: 0x400AC008
Access: Write-only
• UPRSMC: Upstream Resume Interrupt Clear
Writing a one to this bit will clear UPRSM bit in UOTGHS_DEVISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EORSMC: End of Resume Interrupt Clear
Writing a one to this bit will clear EORSM bit in UOTGHS_DEVISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• WAKEUPC: Wake-Up Interrupt Clear
Writing a one to this bit will clear WAKEUP bit in UOTGHS_DEVISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EORSTC: End of Reset Interrupt Clear
Writing a one to this bit will clear EORST bit in UOTGHS_DEVISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SOFC: Start of Frame Interrupt Clear
Writing a one to this bit will clear SOF bit in UOTGHS_DEVISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• MSOFC: Micro Start of Frame Interrupt Clear
Writing a one to this bit will clear MSOF bit in UOTGHS_DEVISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– UPRSMC EORSMC WAKEUPC EORSTC SOFC MSOFC SUSPC
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1104
• SUSPC: Suspend Interrupt Clear
Writing a one to this bit will clear SUSP bit in UOTGHS_DEVISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
1105
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.4 Device Global Interrupt Set Register
Name: UOTGHS_DEVIFR
Address: 0x400AC00C
Access: Write-only
• DMA_x: DMA Channel x Interrupt Set
Writing a one to this bit will set the corresponding bit in UOTGHS_DEVISR, which may be useful for test or debug
purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• UPRSMS: Upstream Resume Interrupt Set
Writing a one to this bit will set UPRSM bit in UOTGHS_DEVISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EORSMS: End of Resume Interrupt Set
Writing a one to this bit will set EORSM bit in UOTGHS_DEVISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• WAKEUPS: Wake-Up Interrupt Set
Writing a one to this bit will set WAKEUP bit in UOTGHS_DEVISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EORSTS: End of Reset Interrupt Set
Writing a one to this bit will set EORST bit in UOTGHS_DEVISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SOFS: Start of Frame Interrupt Set
Writing a one to this bit will set SOF bit in UOTGHS_DEVISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
– DMA_6 DMA_5 DMA_4 DMA_3 DMA_2 DMA_1 –
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– UPRSMS EORSMS WAKEUPS EORSTS SOFS MSOFS SUSPS
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1106
• MSOFS: Micro Start of Frame Interrupt Set
Writing a one to this bit will set MSOF bit in UOTGHS_DEVISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SUSPS: Suspend Interrupt Set
Writing a one to this bit will set SUSP bit in UOTGHS_DEVISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
1107
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.5 Device Global Interrupt Mask Register
Name: UOTGHS_DEVIMR
Address: 0x400AC010
Access: Read-only
• DMA_x: DMA Channel x Interrupt Mask
0: The interrupt is disabled.
1: The interrupt is enabled.
This bit is set when DMA_x bit in UOTGHS_DEVIER is written to one.
This bit is cleared when DMA_x bit in UOTGHS_DEVIDR is written to one.
• PEP_x: Endpoint x Interrupt Mask
0: The interrupt is disabled.
1: The interrupt is enabled.
This bit is set when PEP_x bit in UOTGHS_DEVIER is written to one.
This bit is cleared when PEP_x bit in UOTGHS_DEVIDR is written to one.
• UPRSME: Upstream Resume Interrupt Mask
0: The interrupt is disabled.
1: The interrupt is enabled.
This bit is set when UPRSMES bit in UOTGHS_DEVIER is written to one.
This bit is cleared when UPRSMEC bit in UOTGHS_DEVIDR is written to one.
• EORSME: End of Resume Interrupt Mask
0: The interrupt is disabled.
1: The interrupt is enabled.
This bit is set when EORSMES bit in UOTGHS_DEVIER is written to one.
This bit is cleared when EORSMEC bit in UOTGHS_DEVIDR is written to one.
• WAKEUPE: Wake-Up Interrupt Mask
0: The interrupt is disabled.
1: The interrupt is enabled.
This bit is set when WAKEUPES bit in UOTGHS_DEVIER is written to one.
This bit is cleared when WAKEUPEC bit in UOTGHS_DEVIDR is written to one.
31 30 29 28 27 26 25 24
– DMA_6 DMA_5 DMA_4 DMA_3 DMA_2 DMA_1 –
23 22 21 20 19 18 17 16
– – PEP_9 PEP_8 PEP_7 PEP_6 PEP_5 PEP_4
15 14 13 12 11 10 9 8
PEP_3PEP_2PEP_1PEP_0––––
76543210
– UPRSME EORSME WAKEUPE EORSTE SOFE MSOFE SUSPE
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1108
• EORSTE: End of Reset Interrupt Mask
0: The interrupt is disabled.
1: The interrupt is enabled.
This bit is set when EORSTES bit in UOTGHS_DEVIER is written to one.
This bit is cleared when EORSTEC bit in UOTGHS_DEVIDR is written to one.
• SOFE: Start of Frame Interrupt Mask
0: The interrupt is disabled.
1: The interrupt is enabled.
This bit is set when SOFES bit in UOTGHS_DEVIER is written to one.
This bit is cleared when SOFEC bit in UOTGHS_DEVIDR is written to one.
• MSOFE: Micro Start of Frame Interrupt Mask
0: The interrupt is disabled.
1: The interrupt is enabled.
This bit is set when MSOFES bit in UOTGHS_DEVIER is written to one.
This bit is cleared when MSOFEC bit in UOTGHS_DEVIDR is written to one.
• SUSPE: Suspend Interrupt Mask
0: The interrupt is disabled.
1: The interrupt is enabled.
This bit is set when SUSPES bit in UOTGHS_DEVIER is written to one.
This bit is cleared when SUSPEC bit in UOTGHS_DEVIDR is written to one.
1109
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.6 Device Global Interrupt Disable Register
Name: UOTGHS_DEVIDR
Address: 0x400AC014
Access: Write-only
• DMA_x: DMA Channel x Interrupt Disable
Writing a one to this bit will clear the corresponding bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• PEP_x: Endpoint x Interrupt Disable
Writing a one to this bit will clear the corresponding bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• UPRSMEC: Upstream Resume Interrupt Disable
Writing a one to this bit will clear UPRSME bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EORSMEC: End of Resume Interrupt Disable
Writing a one to this bit will clear EORSME bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• WAKEUPEC: Wake-Up Interrupt Disable
Writing a one to this bit will clear WAKEUPE bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EORSTEC: End of Reset Interrupt Disable
Writing a one to this bit will clear EORSTE bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
– DMA_6 DMA_5 DMA_4 DMA_3 DMA_2 DMA_1 –
23 22 21 20 19 18 17 16
– – PEP_9 PEP_8 PEP_7 PEP_6 PEP_5 PEP_4
15 14 13 12 11 10 9 8
PEP_3PEP_2PEP_1PEP_0––––
76543210
– UPRSMEC EORSMEC WAKEUPEC EORSTEC SOFEC MSOFEC SUSPEC
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1110
• SOFEC: Start of Frame Interrupt Disable
Writing a one to this bit will clear SOFE bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• MSOFEC: Micro Start of Frame Interrupt Disable
Writing a one to this bit will clear MSOFE bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SUSPEC: Suspend Interrupt Disable
Writing a one to this bit will clear SUSPE bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
1111
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.7 Device Global Interrupt Enable Register
Name: UOTGHS_DEVIER
Address: 0x400AC018
Access: Write-only
• DMA_x: DMA Channel x Interrupt Enable
Writing a one to this bit will set the corresponding bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• PEP_x: Endpoint x Interrupt Enable
Writing a one to this bit will set the corresponding bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• UPRSMES: Upstream Resume Interrupt Enable
Writing a one to this bit will set UPRSME bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EORSMES: End of Resume Interrupt Enable
Writing a one to this bit will set EORSME bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• WAKEUPES: Wake-Up Interrupt Enable
Writing a one to this bit will set WAKEUPE bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EORSTES: End of Reset Interrupt Enable
Writing a one to this bit will set EORSTE bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
– DMA_6 DMA_5 DMA_4 DMA_3 DMA_2 DMA_1 –
23 22 21 20 19 18 17 16
– – PEP_9 PEP_8 PEP_7 PEP_6 PEP_5 PEP_4
15 14 13 12 11 10 9 8
PEP_3PEP_2PEP_1PEP_0––––
76543210
– UPRSMES EORSMES WAKEUPES EORSTES SOFES MSOFES SUSPES
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1112
• SOFES: Start of Frame Interrupt Enable
Writing a one to this bit will set SOFE bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• MSOFES: Micro Start of Frame Interrupt Enable
Writing a one to this bit will set MSOFE bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SUSPES: Suspend Interrupt Enable
Writing a one to this bit will set SUSPE bit in UOTGHS_DEVIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
1113
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.8 Device Endpoint Register
Name: UOTGHS_DEVEPT
Address: 0x400AC01C
Access: Read-write
• EPRSTx: Endpoint x Reset
Writing a one to this bit will reset the endpoint x FIFO prior to any other operation, upon hardware reset or when a USB bus
reset has been received. This resets the endpoint x registers (UOTGHS_DEVEPTCFGx, UOTGHS_DEVEPTISRx,
UOTGHS_DEVEPTIMRx) but not the endpoint configuration (UOTGHS_DEVEPTCFGx.ALLOC,
UOTGHS_DEVEPTCFGx.EPBK, UOTGHS_DEVEPTCFGx.EPSIZE, UOTGHS_DEVEPTCFGx.EPDIR,
UOTGHS_DEVEPTCFGx.EPTYPE).
All the endpoint mechanism (FIFO counter, reception, transmission, etc.) is reset apart from the Data Toggle Sequence
field (UOTGHS_DEVEPTISRx.DTSEQ) which can be cleared by setting the UOTGHS_DEVEPTIMRx.RSTDT bit (by writ-
ing a one to the UOTGHS_DEVEPTIERx.RSTDTS bit).
The endpoint configuration remains active and the endpoint is still enabled.
Writing a zero to this bit will complete the reset operation and start using the FIFO.
This bit is cleared upon receiving a USB reset.
• EPENx: Endpoint x Enable
0: The endpoint x is disabled, what forces the endpoint x state to inactive (no answer to USB requests) and resets the end-
point x registers (UOTGHS_DEVEPTCFGx, UOTGHS_DEVEPTISRx, UOTGHS_DEVEPTIMRx) but not the endpoint
configuration (UOTGHS_DEVEPTCFGx.ALLOC, UOTGHS_DEVEPTCFGx.EPBK, UOTGHS_DEVEPTCFGx.EPSIZE,
UOTGHS_DEVEPTCFGx.EPDIR, UOTGHS_DEVEPTCFGx.EPTYPE).
1: The endpoint x is enabled.
31 30 29 28 27 26 25 24
–––––––EPRST8
23 22 21 20 19 18 17 16
EPRST7 EPRST6 EPRST5 EPRST4 EPRST3 EPRST2 EPRST1 EPRST0
15 14 13 12 11 10 9 8
–––––––EPEN8
76543210
EPEN7 EPEN6 EPEN5 EPEN4 EPEN3 EPEN2 EPEN1 EPEN0
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1114
39.6.2.9 Device Frame Number Register
Name: UOTGHS_DEVFNUM
Address: 0x400AC020
Access: Read-only
• FNCERR: Frame Number CRC Error
This bit is set when a corrupted frame number (or micro-frame number) is received. This bit and the SOF (or MSOF) inter-
rupt bit are updated at the same time.
This bit is cleared upon receiving a USB reset.
• FNUM: Frame Number
This field contains the 11-bit frame number information. It is provided in the last received SOF packet.
This field is cleared upon receiving a USB reset.
FNUM is updated even if a corrupted SOF is received.
• MFNUM: Micro Frame Number
This field contains the 3-bit micro frame number information. It is provided in the last received MSOF packet.
This field is cleared at the beginning of each start of frame (SOF interrupt) or upon receiving a USB reset.
MFNUM is updated even if a corrupted MSOF is received.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
FNCERR – FNUM
76543210
FNUM MFNUM
1115
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.10 Device Endpoint x Configuration Register
Name: UOTGHS_DEVEPTCFGx [x=0..9]
Address: 0x400AC100
Access: Read-write
• NBTRANS: Number of transaction per microframe for isochronous endpoint
This field shall be written to the number of transaction per microframe to perform high-bandwidth isochronous transfer
This field can be written only for endpoint that have this capability (see UOTGHS_FEATURES.ENHBISOx bit). This field is
0 otherwise.
This field is irrelevant for non-isochronous endpoint.
• EPTYPE: Endpoint Type
This field shall be written to select the endpoint type:
This field is cleared upon receiving a USB reset.
• AUTOSW: Automatic Switch
This bit is cleared upon receiving a USB reset.
0: The automatic bank switching is disabled.
1: The automatic bank switching is enabled.
• EPDIR: Endpoint Direction
This bit is cleared upon receiving a USB reset.
0 (OUT): The endpoint direction is OUT.
1 (IN): The endpoint direction is IN (nor for control endpoints).
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– NBTRANS EPTYPE – AUTOSW EPDIR
76543210
– EPSIZE EPBK ALLOC –
Value Name Description
0 0_TRANS reserved to endpoint that does not have the high-bandwidth isochronous capability.
1 1_TRANS default value: one transaction per micro-frame.
2 2_TRANS 2 transactions per micro-frame. This endpoint should be configured as double-bank.
3 3_TRANS 3 transactions per micro-frame. This endpoint should be configured as triple-bank.
Value Name Description
0 CTRL Control
1 ISO Isochronous
2BLKBulk
3 INTRPT Interrupt
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1116
• EPSIZE: Endpoint Size
This field shall be written to select the size of each endpoint bank:
This field is cleared upon receiving a USB reset (except for the endpoint 0).
• EPBK: Endpoint Banks
This field shall be written to select the number of banks for the endpoint:
For control endpoints, a single-bank endpoint (0b00) shall be selected.
This field is cleared upon receiving a USB reset (except for the endpoint 0).
• ALLOC: Endpoint Memory Allocate
Writing a one to this bit will allocate the endpoint memory. The user should check the UOTGHS_DEVEPTISRx.CFGOK bit
to know whether the allocation of this endpoint is correct.
Writing a zero to this bit will free the endpoint memory.
This bit is cleared upon receiving a USB reset (except for the endpoint 0).
Value Name Description
0 8_BYTE 8 bytes
1 16_BYTE 16 bytes
2 32_BYTE 32 bytes
3 64_BYTE 64 bytes
4 128_BYTE 128 bytes
5 256_BYTE 256 bytes
6 512_BYTE 512 bytes
7 1024_BYTE 1024 bytes
Value Name Description
0 1_BANK Single-bank endpoint
1 2_BANK Double-bank endpoint
2 3_BANK Triple-bank endpoint
3 Reserved
1117
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.11 Device Endpoint x Status Register
Name: UOTGHS_DEVEPTISRx [x=0..9]
Address: 0x400AC130
Access: Read-only 0x0100
• BYCT: Byte Count
This field is set with the byte count of the FIFO.
For IN endpoints, incremented after each byte written by the software into the endpoint and decremented after each byte
sent to the host.
For OUT endpoints, incremented after each byte received from the host and decremented after each byte read by the soft-
ware from the endpoint.
This field may be updated one clock cycle after the RWALL bit changes, so the user should not poll this field as an interrupt
bit.
• CFGOK: Configuration OK Status
This bit is updated when the UOTGHS_DEVEPTCFGx.ALLOC bit is written to one.
This bit is set if the endpoint x number of banks (UOTGHS_DEVEPTCFGx.EPBK) and size
(UOTGHS_DEVEPTCFGx.EPSIZE) are correct compared to the maximal allowed number of banks and size for this end-
point and to the maximal FIFO size (i.e. the DPRAM size).
If this bit is cleared, the user shall rewrite correct values to the UOTGHS_DEVEPTCFGx.EPBK and
UOTGHS_DEVEPTCFGx.EPSIZE fields.
• CTRLDIR: Control Direction
This bit is set after a SETUP packet to indicate that the following packet is an IN packet.
This bit is cleared after a SETUP packet to indicate that the following packet is an OUT packet.
Writing a zero or a one to this bit has no effect.
• RWALL: Read-write Allowed
This bit is set for IN endpoints when the current bank is not full, i.e., the user can write further data into the FIFO.
This bit is set for OUT endpoints when the current bank is not empty, i.e., the user can read further data from the FIFO.
This bit is never set if UOTGHS_DEVEPTIMRx.STALLRQ is one or in case of error.
This bit is cleared otherwise.
This bit shall not be used for control endpoints.
31 30 29 28 27 26 25 24
–BYCT
23 22 21 20 19 18 17 16
BYCT – CFGOK CTRLDIR RWALL
15 14 13 12 11 10 9 8
CURRBK NBUSYBK – ERRORTRANS DTSEQ
76543210
SHORTPACKET STALLEDI/
CRCERRI OVERFI NAKINI/
HBISOFLUSHI
NAKOUTI/
HBISOINERRI RXSTPI/
UNDERFI RXOUTI TXINI
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1118
• CURRBK: Current Bank
This bit is set for non-control endpoints, to indicate the current bank:
This field may be updated one clock cycle after the RWALL bit changes, so the user should not poll this field as an interrupt
bit.
• NBUSYBK: Number of Busy Banks
This field is set to indicate the number of busy banks:
For IN endpoints, it indicates the number of banks filled by the user and ready for IN transfer. When all banks are free, this
triggers a PEP_x interrupt if NBUSYBKE is one.
For OUT endpoints, it indicates the number of banks filled by OUT transactions from the host. When all banks are busy,
this triggers a PEP_x interrupt if NBUSYBKE is one.
When the UOTGHS_DEVEPTIMRx.FIFOCON bit is cleared (by writing a one to the UOTGHS_DEVEPTIMRx.FIFOCONC
bit) to validate a new bank, this field is updated two or three clock cycles later to calculate the address of the next bank.
A PEP_x interrupt is triggered if:
• for IN endpoint, UOTGHS_DEVEPTIMRx.NBUSYBKE is one and all the banks are free.
• for OUT endpoint, UOTGHS_DEVEPTIMRx.NBUSYBKE is one and all the banks are busy.
• ERRORTRANS: High-bandwidth isochronous OUT endpoint transaction error Interrupt
This bit is set when a transaction error occurs during the current micro-frame (the data toggle sequencing does not respect
the USB 2.0 standard). This triggers a PEP_x interrupt if UOTGHS_DEVEPTIMRx.ERRORTRANSE is one.
This bit is set as long as the current bank (CURRBK) belongs to the bad n-transactions (n=1,2 or 3) transferred during the
micro-frame. Shall be cleared by software by clearing (at least once) the UOTGHS_DEVEPTIMRx.FIFOCON bit to switch
to the bank that belongs to the next n-transactions (next micro-frame).
Value Name Description
0 BANK0 Current bank is bank0
1 BANK1 Current bank is bank1
2 BANK2 Current bank is bank2
3 Reserved
Value Name Description
0 0_BUSY 0 busy bank (all banks free)
1 1_BUSY 1 busy bank
2 2_BUSY 2 busy banks
3 3_BUSY 3 busy banks
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• DTSEQ: Data Toggle Sequence
This field is set to indicate the PID of the current bank:
For IN transfers, it indicates the data toggle sequence that will be used for the next packet to be sent. This is not relative to
the current bank.
For OUT transfers, this value indicates the last data toggle sequence received on the current bank.
By default, DTSEQ is 0b01, as if the last data toggle sequence was Data1, so the next sent or expected data toggle
sequence should be Data0.
For High-bandwidth isochronous endpoint, a PEP_x interrupt is triggered if:
•UOTGHS_DEVEPTIMRx.MDATAE is one and a MData packet has been received (DTSEQ=MData and
UOTGHS_DEVEPTISRx.RXOUTI is one).
•UOTGHS_DEVEPTISRx.DATAXE is one and a Data0/1/2 packet has been received (DTSEQ=Data0/1/2 and
UOTGHS_DEVEPTISRx.RXOUTI is one)
• SHORTPACKET: Short Packet Interrupt
This bit is set for non-control OUT endpoints, when a short packet has been received.
This triggers a PEP_x interrupt if UOTGHS_DEVEPTIMRx.SHORTPACKETE is one.
This bit is cleared when the SHORTPACKETC bit is written to one. This will acknowledge the interrupt.
• STALLEDI: STALLed Interrupt
This bit is set to signal that a STALL handshake has been sent. To do that, the software has to set the STALLRQ bit (by
writing a one to the STALLRQS bit). This triggers a PEP_x interrupt if STALLEDE is one.
This bit is cleared when the STALLEDIC bit is written to one. This will acknowledge the interrupt.
• CRCERRI: CRC Error Interrupt
This bit is set to signal that a CRC error has been detected in an isochronous OUT endpoint. The OUT packet is stored in
the bank as if no CRC error had occurred. This triggers a PEP_x interrupt if CRCERRE is one.
This bit is cleared when the CRCERRIC bit is written to one. This will acknowledge the interrupt.
• OVERFI: Overflow Interrupt
This bit is set when an overflow error occurs. This triggers a PEP_x interrupt if OVERFE is one.
For all endpoint types, an overflow can occur during OUT stage if the host attempts to write into a bank that is too small for
the packet. The packet is acknowledged and the UOTGHS_DEVEPTISRx.RXOUTI bit is set as if no overflow had
occurred. The bank is filled with all the first bytes of the packet that fit in.
This bit is cleared when the OVERFIC bit is written to one. This will acknowledge the interrupt.
Value Name Description
0 DATA0 Data0 toggle sequence
1 DATA1 Data1 toggle sequence
2 DATA2 Data2 toggle sequence (for high-bandwidth isochronous endpoint)
3 MDATA MData toggle sequence (for high-bandwidth isochronous endpoint)
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1120
• NAKINI: NAKed IN Interrupt
This bit is set when a NAK handshake has been sent in response to an IN request from the host. This triggers a PEP_x
interrupt if NAKINE is one.
This bit is cleared when the NAKINIC bit is written to one. This will acknowledge the interrupt.
• HBISOFLUSHI: High Bandwidth Isochronous IN Flush Interrupt
This bit is set, for High-bandwidth isochronous IN endpoint (with NBTRANS=2 or 3), at the end of the micro-frame, if less
than N transaction has been completed by the UOTGHS without underflow error. This may occur in case of a missing IN
token. In this case, the bank are flushed out to ensure the data synchronization between the host and the device. This trig-
gers a PEP_x interrupt if HBISOFLUSHE is one.
This bit is cleared when the HBISOFLUSHIC bit is written to one. This will acknowledge the interrupt.
• NAKOUTI: NAKed OUT Interrupt
This bit is set when a NAK handshake has been sent in response to an OUT request from the host. This triggers a PEP_x
interrupt if NAKOUTE is one.
This bit is cleared when the NAKOUTIC bit is written to one. This will acknowledge the interrupt.
• HBISOINERRI: High bandwidth isochronous IN Underflow Error Interrupt
This bit is set, for High-bandwidth isochronous IN endpoint (with NBTRANS=2 or 3), at the end of the microframe, if less
than N bank was written by the cpu within this micro-frame. This triggers a PEP_x interrupt if HBISOINERRE is one.
This bit is cleared when the HBISOINERRIC bit is written to one. This will acknowledge the interrupt.
• UNDERFI: Underflow Interrupt
This bit is set, for isochronous IN/OUT endpoints, when an underflow error occurs. This triggers a PEP_x interrupt if
UNDERFE is one.
An underflow can occur during IN stage if the host attempts to read from an empty bank. A zero-length packet is then auto-
matically sent by the UOTGHS.
An underflow can also occur during OUT stage if the host sends a packet while the bank is already full. Typically, the CPU
is not fast enough. The packet is lost.
Shall be cleared by writing a one to the UNDERFIC bit. This will acknowledge the interrupt.
This bit is inactive (cleared) for bulk and interrupt IN/OUT endpoints and it means RXSTPI for control endpoints.
• RXSTPI: Received SETUP Interrupt
This bit is set, for control endpoints, to signal that the current bank contains a new valid SETUP packet. This triggers a
PEP_x interrupt if RXSTPE is one.
Shall be cleared by writing a one to the RXSTPIC bit. This will acknowledge the interrupt and free the bank.
This bit is inactive (cleared) for bulk and interrupt IN/OUT endpoints and it means UNDERFI for isochronous IN/OUT
endpoints.
• RXOUTI: Received OUT Data Interrupt
This bit is set, for control endpoints, when the current bank contains a bulk OUT packet (data or status stage). This triggers
a PEP_x interrupt if UOTGHS_DEVEPTIMRx.RXOUTE is one.
Shall be cleared for control end points, by writing a one to the RXOUTIC bit. This will acknowledge the interrupt and free
the bank.
This bit is set for isochronous, bulk and, interrupt OUT endpoints, at the same time as UOTGHS_DEVEPTIMRx.FIFOCON
when the current bank is full. This triggers a PEP_x interrupt if UOTGHS_DEVEPTIMRx.RXOUTE is one.
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Shall be cleared for isochronous, bulk and, interrupt OUT endpoints, by writing a one to the RXOUTIC bit. This will
acknowledge the interrupt, what has no effect on the endpoint FIFO.
The user then reads from the FIFO and clears the UOTGHS_DEVEPTIMRx.FIFOCON bit to free the bank. If the OUT end-
point is composed of multiple banks, this also switches to the next bank. The UOTGHS_DEVEPTISRx.RXOUTI and
UOTGHS_DEVEPTIMRx.FIFOCON bits are set/cleared in accordance with the status of the next bank.
UOTGHS_DEVEPTISRx.RXOUTI shall always be cleared before clearing UOTGHS_DEVEPTIMRx.FIFOCON.
This bit is inactive (cleared) for isochronous, bulk and interrupt IN endpoints.
• TXINI: Transmitted IN Data Interrupt
This bit is set for control endpoints, when the current bank is ready to accept a new IN packet. This triggers a PEP_x inter-
rupt if TXINE is one.
This bit is cleared when the TXINIC bit is written to one. This will acknowledge the interrupt and send the packet.
This bit is set for isochronous, bulk and interrupt IN endpoints, at the same time as UOTGHS_DEVEPTIMRx.FIFOCON
when the current bank is free. This triggers a PEP_x interrupt if TXINE is one.
This bit is cleared when the TXINIC bit is written to one. This will acknowledge the interrupt, what has no effect on the end-
point FIFO.
The user then writes into the FIFO and clears the UOTGHS_DEVEPTIMRx.FIFOCON bit to allow the UOTGHS to send
the data. If the IN endpoint is composed of multiple banks, this also switches to the next bank. The
UOTGHS_DEVEPTISRx.TXINI and UOTGHS_DEVEPTIMRx.FIFOCON bits are set/cleared in accordance with the status
of the next bank.
UOTGHS_DEVEPTISRx.TXINI shall always be cleared before clearing UOTGHS_DEVEPTIMRx.FIFOCON.
This bit is inactive (cleared) for isochronous, bulk and interrupt OUT endpoints.
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1122
39.6.2.12 Device Endpoint x Clear Register
Name: UOTGHS_DEVEPTICRx [x=0..9]
Address: 0x400AC160
Access: Write-only
• SHORTPACKETC: Short Packet Interrupt Clear
Writing a one to this bit will clear SHORTPACKET in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• STALLEDIC: STALLed Interrupt Clear
Writing a one to this bit will clear STALLEDI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• CRCERRIC: CRC Error Interrupt Clear
Writing a one to this bit will clear CRCERRI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• OVERFIC: Overflow Interrupt Clear
Writing a one to this bit will clear OVERFI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKINIC: NAKed IN Interrupt Clear
Writing a one to this bit will clear NAKINI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HBISOFLUSHIC: High Bandwidth Isochronous IN Flush Interrupt Clear
Writing a one to this bit will clear HBISOFLUSHI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
SHORT
PACKETC
STALLEDIC/
CRCERRIC OVERFIC NAKINIC/
HBISOFLUSHIC
NAKOUTIC/
HBISOINERRIC
RXSTPIC/
UNDERFIC RXOUTIC TXINIC
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• NAKOUTIC: NAKed OUT Interrupt Clear
Writing a one to this bit will clear NAKOUTI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HBISOINERRIC: High bandwidth isochronous IN Underflow Error Interrupt Clear
Writing a one to this bit will clear HBISOINERRI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXSTPIC: Received SETUP Interrupt Clear
Writing a one to this bit will clear RXSTPI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• UNDERFIC: Underflow Interrupt Clear
Writing a one to this bit will clear UNDERFI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXOUTIC: Received OUT Data Interrupt Clear
Writing a one to this bit will clear RXOUTI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXINIC: Transmitted IN Data Interrupt Clear
Writing a one to this bit will clear TXINI in UOTGHS_DEVEPTISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
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1124
39.6.2.13 Device Endpoint x Set Register
Name: UOTGHS_DEVEPTIFRx [x=0..9]
Address: 0x400AC190
Access: Write-only
• NBUSYBKS: Number of Busy Banks Interrupt Set
Writing a one to this bit will set NBUSYBK in UOTGHS_DEVEPTISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SHORTPACKETS: Short Packet Interrupt Set
Writing a one to this bit will set SHORTPACKET in UOTGHS_DEVEPTISRx, which may be useful for test or debug
purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• STALLEDIS: STALLed Interrupt Set
Writing a one to this bit will set STALLEDI in UOTGHS_DEVEPTISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• CRCERRIS: CRC Error Interrupt Set
Writing a one to this bit will set CRCERRI in UOTGHS_DEVEPTISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• OVERFIS: Overflow Interrupt Set
Writing a one to this bit will set OVERFI in UOTGHS_DEVEPTISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKINIS: NAKed IN Interrupt Set
Writing a one to this bit will set NAKINI in UOTGHS_DEVEPTISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – – NBUSYBKS ––––
76543210
SHORT
PACKETS
STALLEDIS/
CRCERRIS OVERFIS NAKINIS/
HBISOFLUSHIS
NAKOUTIS/
HBISOINERRIS
RXSTPIS/
UNDERFIS RXOUTIS TXINIS
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• HBISOFLUSHIS: High Bandwidth Isochronous IN Flush Interrupt Set
Writing a one to this bit will set HBISOFLUSHI in UOTGHS_DEVEPTISRx, which may be useful for test or debug
purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKOUTIS: NAKed OUT Interrupt Set
Writing a one to this bit will set NAKOUTI in UOTGHS_DEVEPTISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HBISOINERRIS: High bandwidth isochronous IN Underflow Error Interrupt Set
Writing a one to this bit will set HBISOINERRI in UOTGHS_DEVEPTISRx, which may be useful for test or debug
purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXSTPIS: Received SETUP Interrupt Set
Writing a one to this bit will set RXSTPI in UOTGHS_DEVEPTISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• UNDERFIS: Underflow Interrupt Set
Writing a one to this bit will set UNDERFI in UOTGHS_DEVEPTISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXOUTIS: Received OUT Data Interrupt Set
Writing a one to this bit will set RXOUTI in UOTGHS_DEVEPTISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXINIS: Transmitted IN Data Interrupt Set
Writing a one to this bit will set TXINI in UOTGHS_DEVEPTISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
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1126
39.6.2.14 Device Endpoint x Mask Register
Name: UOTGHS_DEVEPTIMRx [x=0..9]
Address: 0x400AC1C0
Access: Read-only
• STALLRQ: STALL Request
This bit is set when UOTGHS_DEVEPTIERx.STALLRQS bit is written to one. This will request to send a STALL hand-
shake to the host.
This bit is cleared when a new SETUP packet is received or when the UOTGHS_DEVEPTIDRx.STALLRQC bit is written to
zero.
• RSTDT: Reset Data Toggle
This bit is set when UOTGHS_DEVEPTIERx.RSTDTS bit is written to one. This will clear the data toggle sequence, i.e.,
set to Data0 the data toggle sequence of the next sent (IN endpoints) or received (OUT endpoints) packet.
This bit is cleared instantaneously.
The user does not have to wait for this bit to be cleared.
• NYETDIS: NYET Token Disable
This bit is set when UOTGHS_DEVEPTIERx.NYETDISS bit is written to one. This will send a ACK handshake instead of a
NYET handshake in high-speed mode.
This bit is cleared when the UOTGHS_DEVEPTIDRx.NYETDISC bit is written to one.This will let the UOTGHS handling
the high-speed handshake following the USB 2.0 standard.
• EPDISHDMA: Endpoint Interrupts Disable HDMA Request
This bit is set when the UOTGHS_DEVEPTIERx.EPDISHDMAS is written to one. This will pause the on-going DMA chan-
nel x transfer on any Endpoint x interrupt (PEP_x), whatever the state of the Endpoint x Interrupt Enable bit (PEP_x).
The user then has to acknowledge or to disable the interrupt source (e.g. UOTGHS_DEVEPTISRx.RXOUTI) or to clear the
EPDISHDMA bit (by writing a one to UOTGHS_DEVEPTIDRx.EPDISHDMAC bit) in order to complete the DMA transfer.
In ping-pong mode, if the interrupt is associated to a new system-bank packet (e.g. Bank1) and the current DMA transfer is
running on the previous packet (Bank0), then the previous-packet DMA transfer completes normally, but the new-packet
DMA transfer will not start (not requested).
If the interrupt is not associated to a new system-bank packet (UOTGHS_DEVEPTISRx.NAKINI, NAKOUTI, etc.), then the
request cancellation may occur at any time and may immediately pause the current DMA transfer.
This may be used for example to identify erroneous packets, to prevent them from being transferred into a buffer, to com-
plete a DMA transfer by software after reception of a short packet, etc.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––STALLRQRSTDTNYETDISEPDISHDMA
15 14 13 12 11 10 9 8
– FIFOCON KILLBK NBUSYBKE – ERRORTRANSE DATAXE MDATAE
76543210
SHORTPACKETE STALLEDE/
CRCERRE OVERFE NAKINE/
HBISOFLUSHE
NAKOUTE/
HBISOINERRE
RXSTPE/
UNDERFE RXOUTE TXINE
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• FIFOCON: FIFO Control
For control endpoints:
The FIFOCON and RWALL bits are irrelevant. The software shall therefore never use them on these endpoints. When
read, their value is always 0.
For IN endpoints:
This bit is set when the current bank is free, at the same time as UOTGHS_DEVEPTISRx.TXINI.
This bit is cleared (by writing a one to UOTGHS_DEVEPTIDRx.FIFOCONC bit) to send the FIFO data and to switch to
the next bank.
For OUT endpoints:
This bit is set when the current bank is full, at the same time as UOTGHS_DEVEPTISRx.RXOUTI.
This bit is cleared (by writing a one to UOTGHS_DEVEPTIDRx.FIFOCONC bit) to free the current bank and to switch
to the next bank.
• KILLBK: Kill IN Bank
This bit is set when UOTGHS_DEVEPTIERx.KILLBKS bit is written to one. This will kill the last written bank.
This bit is cleared when the bank is killed.
Caution: The bank is really cleared when the “kill packet” procedure is accepted by the UOTGHS core. This bit is automat-
ically cleared after the end of the procedure:
The bank is really killed: UOTGHS_DEVEPTISRx.NBUSYBK is decremented.
The bank is not cleared but sent (IN transfer): UOTGHS_DEVEPTISRx.NBUSYBK is decremented.
The bank is not cleared because it was empty.
The user shall wait for this bit to be cleared before trying to kill another packet.
This kill request is refused if at the same time an IN token is coming and the last bank is the current one being sent on the
USB line. If at least 2 banks are ready to be sent, there is no problem to kill a packet even if an IN token is coming. Indeed,
in this case, the current bank is sent (IN transfer) while the last bank is killed.
• NBUSYBKE: Number of Busy Banks Interrupt
This bit is set when UOTGHS_DEVEPTIERx.NBUSYBKES bit is written to one. This will enable the Number of Busy Banks
interrupt (UOTGHS_DEVEPTISRx.NBUSYBK).
This bit is cleared when UOTGHS_DEVEPTIDRx.NBUSYBKEC bit is written to zero. This will disable the Number of Busy
Banks interrupt (UOTGHS_DEVEPTISRx.NBUSYBK).
• ERRORTRANSE: Transaction Error Interrupt
This bit is set when UOTGHS_DEVEPTIERx.ERRORTRANSES bit is written to one. This will enable the transaction error
interrupt (UOTGHS_DEVEPTISRx.ERRORTRANS).
This bit is cleared when UOTGHS_DEVEPTIDRx.ERRORTRANSEC bit is written to one. This will disable the transaction
error interrupt (UOTGHS_DEVEPTISRx.ERRORTRANS).
• DATAXE: DataX Interrupt
This bit is set when UOTGHS_DEVEPTIERx.DATAXES bit is written to one. This will enable the DATAX interrupt. (see
DTSEQ bits)
This bit is cleared when UOTGHS_DEVEPTIDRx.DATAXEC bit is written to one. This will disable the DATAX interrupt.
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1128
• MDATAE: MData Interrupt
This bit is set when UOTGHS_DEVEPTIERx.MDATAES bit is written to one. This will enable the Multiple DATA interrupt.
(see DTSEQ bits)
This bit is cleared when UOTGHS_DEVEPTIDRx.MDATAEC bit is written to one. This will disable the Multiple DATA
interrupt.
• SHORTPACKETE: Short Packet Interrupt
If this bit is set for non-control IN endpoints, a short packet transmission is guaranteed upon ending a DMA transfer, thus
signaling an end of isochronous frame or a bulk or interrupt end of transfer, provided that he End of DMA Buffer Output
Enable (END_B_EN) bit and the Automatic Switch (AUTOSW) bit are written to one.
This bit is set when UOTGHS_DEVEPTIERx.SHORTPACKETES bit is written to one. This will enable the Short Packet
interrupt (UOTGHS_DEVEPTISRx.SHORTPACKET).
This bit is cleared when UOTGHS_DEVEPTIDRx.SHORTPACKETEC bit is written to one. This will disable the Short
Packet interrupt (UOTGHS_DEVEPTISRx.SHORTPACKET).
• STALLEDE: STALLed Interrupt
This bit is set when UOTGHS_DEVEPTIERx.STALLEDES bit is written to one. This will enable the STALLed interrupt
(UOTGHS_DEVEPTISRx.STALLEDI).
This bit is cleared when UOTGHS_DEVEPTIDRx.STALLEDEC bit is written to one. This will disable the STALLed interrupt
(UOTGHS_DEVEPTISRx.STALLEDI).
• CRCERRE: CRC Error Interrupt
This bit is set when UOTGHS_DEVEPTIERx.CRCERRES bit is written to one. This will enable the CRC Error interrupt
(UOTGHS_DEVEPTISRx.CRCERRI).
This bit is cleared when UOTGHS_DEVEPTIDRx.CRCERREC bit is written to one. This will disable the CRC Error inter-
rupt (UOTGHS_DEVEPTISRx.CRCERRI).
• OVERFE: Overflow Interrupt
This bit is set when UOTGHS_DEVEPTIERx.OVERFES bit is written to one. This will enable the Overflow interrupt
(UOTGHS_DEVEPTISRx.OVERFI).
This bit is cleared when UOTGHS_DEVEPTIDRx.OVERFEC bit is written to one. This will disable the Overflow interrupt
(UOTGHS_DEVEPTISRx.OVERFI).
• NAKINE: NAKed IN Interrupt
This bit is set when UOTGHS_DEVEPTIERx.NAKINES bit is written to one. This will enable the NAKed IN interrupt
(UOTGHS_DEVEPTISRx.NAKINI).
This bit is cleared when UOTGHS_DEVEPTIDRx.NAKINEC bit is written to one. This will disable the NAKed IN interrupt
(UOTGHS_DEVEPTISRx.NAKINI).
• HBISOFLUSHE: High Bandwidth Isochronous IN Flush Interrupt
This bit is set when UOTGHS_DEVEPTIERx.HBISOFLUSHES bit is written to one. This will enable the HBISOFLUSHI
interrupt.
This bit is cleared when UOTGHS_DEVEPTIDRx.HBISOFLUSHEC bit disable the HBISOFLUSHI interrupt.
AtmeL
1129
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• NAKOUTE: NAKed OUT Interrupt
This bit is set when UOTGHS_DEVEPTIERx.NAKOUTES bit is written to one. This will enable the NAKed OUT interrupt
(UOTGHS_DEVEPTISRx.NAKOUTI).
This bit is cleared when UOTGHS_DEVEPTIDRx.NAKOUTEC bit is written to one. This will disable the NAKed OUT inter-
rupt (UOTGHS_DEVEPTISRx.NAKOUTI).
• HBISOINERRE: High Bandwidth Isochronous IN Error Interrupt
This bit is set when UOTGHS_DEVEPTIERx.HBISOINERRES bit is written to one. This will enable the HBISOINERRI
interrupt.
This bit is cleared when UOTGHS_DEVEPTIDRx.HBISOINERREC bit disable the HBISOINERRI interrupt.
• RXSTPE: Received SETUP Interrupt
This bit is set when UOTGHS_DEVEPTIERx.RXSTPES bit is written to one. This will enable the Received SETUP inter-
rupt (UOTGHS_DEVEPTISRx.RXSTPI).
This bit is cleared when UOTGHS_DEVEPTIERx.RXSTPEC bit is written to one. This will disable the Received SETUP
interrupt (UOTGHS_DEVEPTISRx.RXSTPI).
• UNDERFE: Underflow Interrupt
This bit is set when UOTGHS_DEVEPTIERx.UNDERFES bit is written to one. This will enable the Underflow interrupt
(UOTGHS_DEVEPTISRx.UNDERFI).
This bit is cleared when UOTGHS_DEVEPTIDRx.UNDERFEC bit is written to one. This will disable the Underflow interrupt
(UOTGHS_DEVEPTISRx.UNDERFI).
• RXOUTE: Received OUT Data Interrupt
This bit is set when UOTGHS_DEVEPTIERx.RXOUTES bit is written to one. This will enable the Received OUT Data inter-
rupt (UOTGHS_DEVEPTISRx.RXOUTI).
This bit is cleared when the UOTGHS_DEVEPTIDRx.RXOUTEC bit is written to one. This will disable the Received OUT
Data interrupt (UOTGHS_DEVEPTISRx.RXOUTI).
• TXINE: Transmitted IN Data Interrupt
This bit is set when UOTGHS_DEVEPTIERx.TXINES bit is written to one. This will enable the Transmitted IN Data inter-
rupt (UOTGHS_DEVEPTISRx.TXINI).
This bit is cleared when UOTGHS_DEVEPTIDRx.TXINEC bit is written to one. This will disable the Transmitted IN Data
interrupt (UOTGHS_DEVEPTISRx.TXINI).
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1130
39.6.2.15 Device Endpoint x Disable Register
Name: UOTGHS_DEVEPTIDRx [x=0..9]
Address: 0x400AC220
Access: Write-only
• STALLRQC: STALL Request Clear
Writing a one to this bit will clear STALLRQ bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NYETDISC: NYET Token Disable Clear
Writing a one to this bit will clear NYETDIS bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EPDISHDMAC: Endpoint Interrupts Disable HDMA Request Clear
Writing a one to this bit will clear EPDISHDMA bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• FIFOCONC: FIFO Control Clear
Writing a one to this bit will clear FIFOCON bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NBUSYBKEC: Number of Busy Banks Interrupt Clear
Writing a one to this bit will clear NBUSYBKE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• ERRORTRANSEC: Transaction Error Interrupt Clear
Writing a one to this bit will clear ERRORTRANSE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––STALLRQC–NYETDISCEPDISHDMAC
15 14 13 12 11 10 9 8
– FIFOCONC – NBUSYBKEC – ERRORTRANSEC DATAXEC MDATEC
76543210
SHORT
PACKETEC
STALLEDEC/
CRCERREC OVERFEC NAKINEC/
HBISOFLUSHEC
NAKOUTEC/
HBISOINERREC
RXSTPEC/
UNDERFEC RXOUTEC TXINEC
AtmeL
1131
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• DATAXEC: DataX Interrupt Clear
Writing a one to this bit will clear DATAXE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• MDATEC: MData Interrupt Clear
Writing a one to this bit will clear MDATE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SHORTPACKETEC: Shortpacket Interrupt Clear
Writing a one to this bit will clear SHORTPACKETE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• STALLEDEC: STALLed Interrupt Clear
Writing a one to this bit will clear STALLEDE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• CRCERREC: CRC Error Interrupt Clear
Writing a one to this bit will clear CRCERRE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• OVERFEC: Overflow Interrupt Clear
Writing a one to this bit will clear OVERFE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKINEC: NAKed IN Interrupt Clear
Writing a one to this bit will clear NAKINE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HBISOFLUSHEC: High Bandwidth Isochronous IN Flush Interrupt Clear
Writing a one to this bit will clear HBISOFLUSHE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKOUTEC: NAKed OUT Interrupt Clear
Writing a one to this bit will clear NAKOUTE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1132
• HBISOINERREC: High Bandwidth Isochronous IN Error Interrupt Clear
Writing a one to this bit will clear HBISOINERRE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXSTPEC: Received SETUP Interrupt Clear
Writing a one to this bit will clear RXSTPE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• UNDERFEC: Underflow Interrupt Clear
Writing a one to this bit will clear UNDERFE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXOUTEC: Received OUT Data Interrupt Clear
Writing a one to this bit will clear RXOUTE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXINEC: Transmitted IN Interrupt Clear
Writing a one to this bit will clear TXINE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
AtmeL
1133
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.16 Device Endpoint x Enable Register
Name: UOTGHS_DEVEPTIERx [x=0..9]
Address: 0x400AC1F0
Access: Write-only
• STALLRQS: STALL Request Enable
Writing a one to this bit will set STALLRQ bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RSTDTS: Reset Data Toggle Enable
Writing a one to this bit will set RSTDT bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NYETDISS: NYET Token Disable Enable
Writing a one to this bit will set NYETDIS bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EPDISHDMAS: Endpoint Interrupts Disable HDMA Request Enable
Writing a one to this bit will set EPDISHDMA bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• FIFOCONS: FIFO Control
Writing a one to this bit will set FIFOCON bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• KILLBKS: Kill IN Bank
Writing a one to this bit will set KILLBK bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––STALLRQSRSTDTSNYETDISSEPDISHDMAS
15 14 13 12 11 10 9 8
– – KILLBKS NBUSYBKES – ERRORTRANS
ES DATAXES MDATAES
76543210
SHORTPACKE
TES STALLEDES/
CRCERRES OVERFES NAKINES/
HBISOFLUSHE
S
NAKOUTES/
HBISOINERRE
S
RXSTPES/
UNDERFES RXOUTES TXINES
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1134
• NBUSYBKES: Number of Busy Banks Interrupt Enable
Writing a one to this bit will set NBUSYBKE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• ERRORTRANSES: Transaction Error Interrupt Enable
Writing a one to this bit will set ERRORTRANSE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• DATAXES: DataX Interrupt Enable
Writing a one to this bit will set DATAXE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• MDATAES: MData Interrupt Enable
Writing a one to this bit will set MDATAE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SHORTPACKETES: Short Packet Interrupt Enable
Writing a one to this bit will set SHORTPACKETE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• STALLEDES: STALLed Interrupt Enable
Writing a one to this bit will set STALLEDE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• CRCERRES: CRC Error Interrupt Enable
Writing a one to this bit will set CRCERRE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• OVERFES: Overflow Interrupt Enable
Writing a one to this bit will set OVERFE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKINES: NAKed IN Interrupt Enable
Writing a one to this bit will set NAKINE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
AtmeL
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• HBISOFLUSHES: High Bandwidth Isochronous IN Flush Interrupt Enable
Writing a one to this bit will set HBISOFLUSHE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKOUTES: NAKed OUT Interrupt Enable
Writing a one to this bit will set NAKOUTE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HBISOINERRES: High Bandwidth Isochronous IN Error Interrupt Enable
Writing a one to this bit will set HBISOINERRE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXSTPES: Received SETUP Interrupt Enable
Writing a one to this bit will set RXSTPE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• UNDERFES: Underflow Interrupt Enable
Writing a one to this bit will set UNDERFE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXOUTES: Received OUT Data Interrupt Enable
Writing a one to this bit will set RXOUTE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXINES: Transmitted IN Data Interrupt Enable
Writing a one to this bit will set TXINE bit in UOTGHS_DEVEPTIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1136
39.6.2.17 Device DMA Channel x Next Descriptor Address Register
Name: UOTGHS_DEVDMANXTDSCx [x=1..6]
Address: 0x400AC310 [1], 0x400AC320 [2], 0x400AC330 [3], 0x400AC340 [4], 0x400AC350 [5], 0x400AC360 [6],
0x400AC370 [7]
Access: Read-write
• NXT_DSC_ADD: Next Descriptor Address
This field points to the next channel descriptor to be processed. This channel descriptor must be aligned, so bits 0 to 3 of
the address must be equal to zero.
31 30 29 28 27 26 25 24
NXT_DSC_ADD
23 22 21 20 19 18 17 16
NXT_DSC_ADD
15 14 13 12 11 10 9 8
NXT_DSC_ADD
76543210
NXT_DSC_ADD
1137
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.2.18 Device DMA Channel x Address Register
Name: UOTGHS_DEVDMAADDRESSx [x=1..6]
Address: 0x400AC314 [1], 0x400AC324 [2], 0x400AC334 [3], 0x400AC344 [4], 0x400AC354 [5], 0x400AC364 [6],
0x400AC374 [7]
Access: Read-write
• BUFF_ADD: Buffer Address
This field determines the AHB bus starting address of a DMA channel transfer.
Channel start and end addresses may be aligned on any byte boundary.
The firmware may write this field only when the UOTGHS_DEVDMASTATUS.CHANN_ENB bit is clear.
This field is updated at the end of the address phase of the current access to the AHB bus. It is incrementing of the access
byte width. The access width is 4 bytes (or less) at packet start or end, if the start or end address is not aligned on a word
boundary.
The packet start address is either the channel start address or the next channel address to be accessed in the channel
buffer.
The packet end address is either the channel end address or the latest channel address accessed in the channel buffer.
The channel start address is written by software or loaded from the descriptor, whereas the channel end address is either
determined by the end of buffer or the USB device, USB end of transfer if the
UOTGHS_DEVDMACONTROLx.END_TR_EN bit is set.
31 30 29 28 27 26 25 24
BUFF_ADD
23 22 21 20 19 18 17 16
BUFF_ADD
15 14 13 12 11 10 9 8
BUFF_ADD
76543210
BUFF_ADD
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1138
39.6.2.19 Device DMA Channel x Control Register
Name: UOTGHS_DEVDMACONTROLx [x=1..6]
Address: 0x400AC318 [1], 0x400AC328 [2], 0x400AC338 [3], 0x400AC348 [4], 0x400AC358 [5], 0x400AC368 [6],
0x400AC378 [7]
Access: Read-write
• CHANN_ENB: Channel Enable Command
0: DMA channel is disabled at and no transfer will occur upon request. This bit is also cleared by hardware when the chan-
nel source bus is disabled at end of buffer.
If LDNXT_DSC bit has been cleared by descriptor loading, the firmware will have to set the corresponding
CHANN_ENB bit to start the described transfer, if needed.
If LDNXT_DSC bit is cleared, the channel is frozen and the channel registers may then be read and/or written reliably
as soon as both UOTGHS_DEVDMASTATUS.CHANN_ENB and CHANN_ACT flags read as 0.
If a channel request is currently serviced when this bit is cleared, the DMA FIFO buffer is drained until it is empty, then
the UOTGHS_DEVDMASTATUS.CHANN_ENB bit is cleared.
If LDNXT_DSC bit is set at or after this bit clearing, then the currently loaded descriptor is skipped (no data transfer
occurs) and the next descriptor is immediately loaded.
1: UOTGHS_DEVDMASTATUS.CHANN_ENB bit will be set, thus enabling DMA channel data transfer. Then any pending
request will start the transfer. This may be used to start or resume any requested transfer.
• LDNXT_DSC: Load Next Channel Transfer Descriptor Enable Command
0: no channel register is loaded after the end of the channel transfer.
1: the channel controller loads the next descriptor after the end of the current transfer, i.e. when
UOTGHS_DEVDMASTATUS.CHANN_ENB bit is reset.
If CHANN_ENB bit is cleared, the next descriptor is immediately loaded upon transfer request.
DMA Channel Control Command Summary
31 30 29 28 27 26 25 24
BUFF_LENGTH
23 22 21 20 19 18 17 16
BUFF_LENGTH
15 14 13 12 11 10 9 8
––––––––
76543210
BURST_LCK DESC_LD_IT END_BUFFIT END_TR_IT END_B_EN END_TR_EN LDNXT_DSC CHANN_ENB
Value Name Description
0STOP_NOW Stop now
1 RUN_AND_STOP Run and stop at end of buffer
2 LOAD_NEXT_DESC Load next descriptor now
3 RUN_AND_LINK Run and link at end of buffer
AtmeL
1139
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• END_TR_EN: End of Transfer Enable Control
Used for OUT transfers only.
0: USB end of transfer is ignored.
1: UOTGHS device can put an end to the current buffer transfer.
When set, a BULK or INTERRUPT short packet or the last packet of an ISOCHRONOUS (micro) frame (DATAX) will close
the current buffer and the UOTGHS_DEVDMASTATUSx.END_TR_ST flag will be raised.
This is intended for UOTGHS non-prenegotiated end of transfer (BULK or INTERRUPT) or ISOCHRONOUS microframe
data buffer closure.
• END_B_EN: End of Buffer Enable Control
0: DMA Buffer End has no impact on USB packet transfer.
1: the endpoint can validate the packet (according to the values programmed in the UOTGHS_DEVEPTCFGx.AUTOSW
field, and in the UOTGHS_DEVEPTIERx.SHORTPACKETES field) at DMA Buffer End, i.e. when the
UOTGHS_DEVDMASTATUS.BUFF_COUNT reaches 0.
This is mainly for short packet IN validation initiated by the DMA reaching end of buffer, but could be used for OUT packet
truncation (discarding of unwanted packet data) at the end of DMA buffer.
• END_TR_IT: End of Transfer Interrupt Enable
0: UOTGHS device initiated buffer transfer completion will not trigger any interrupt at
UOTGHS_DEVDMASTATUSx.END_TR_ST rising.
1: an interrupt is sent after the buffer transfer is complete, if the UOTGHS device has ended the buffer transfer.
Use when the receive size is unknown.
• END_BUFFIT: End of Buffer Interrupt Enable
0: UOTGHS_DEVDMA_STATUSx.END_BF_ST rising will not trigger any interrupt.
1: an interrupt is generated when the UOTGHS_HSTDMASTATUSx.BUFF_COUNT reaches zero.
• DESC_LD_IT: Descriptor Loaded Interrupt Enable
0: UOTGHS_DEVDMASTATUSx.DESC_LDST rising will not trigger any interrupt.
1: an interrupt is generated when a descriptor has been loaded from the bus.
• BURST_LCK: Burst Lock Enable
0: the DMA never locks bus access.
1: USB packets AHB data bursts are locked for maximum optimization of the bus bandwidth usage and maximization of fly-
by AHB burst duration.
• BUFF_LENGTH: Buffer Byte Length (Write-only)
This field determines the number of bytes to be transferred until end of buffer. The maximum channel transfer size
(32 KBytes) is reached when this field is 0 (default value). If the transfer size is unknown, this field should be set to 0, but
the transfer end may occur earlier under USB device control.
When this field is written, The UOTGHS_DEVDMASTATUSx.BUFF_COUNT field is updated with the write value.
Notes: 1. Bits [31:2] are only writable when issuing a channel Control Command other than “Stop Now”.
2. For reliability it is highly recommended to wait for both UOTGHS_DEVDMASTATUSx.CHAN_ACT and
UOTGHS_DEVDMASTATUSx.CHAN_ENB flags are at 0, thus ensuring the channel has been stopped before issuing a
command other than “Stop Now”.
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1140
39.6.2.20 Device DMA Channel x Status Register
Name: UOTGHS_DEVDMASTATUSx [x=1..6]
Address: 0x400AC31C [1], 0x400AC32C [2], 0x400AC33C [3], 0x400AC34C [4], 0x400AC35C [5], 0x400AC36C [6],
0x400AC37C [7]
Access: Read-write
• CHANN_ENB: Channel Enable Status
0: if cleared, the DMA channel no longer transfers data, and may load the next descriptor if the
UOTGHS_DEVDMACONTROLx.LDNXT_DSC bit is set.
When any transfer is ended either due to an elapsed byte count or a UOTGHS device initiated transfer end, this bit is auto-
matically reset.
1: if set, the DMA channel is currently enabled and transfers data upon request.
This bit is normally set or cleared by writing into the UOTGHS_DEVDMACONTROLx.CHANN_ENB bit field either by soft-
ware or descriptor loading.
If a channel request is currently serviced when the UOTGHS_DEVDMACONTROLx.CHANN_ENB bit is cleared, the DMA
FIFO buffer is drained until it is empty, then this status bit is cleared.
• CHANN_ACT: Channel Active Status
0: the DMA channel is no longer trying to source the packet data.
When a packet transfer is ended this bit is automatically reset.
1: the DMA channel is currently trying to source packet data, i.e. selected as the highest-priority requesting channel.
When a packet transfer cannot be completed due to an END_BF_ST, this flag stays set during the next channel descriptor
load (if any) and potentially until UOTGHS packet transfer completion, if allowed by the new descriptor.
• END_TR_ST: End of Channel Transfer Status
0: cleared automatically when read by software.
1: set by hardware when the last packet transfer is complete, if the UOTGHS device has ended the transfer.
Valid until the CHANN_ENB flag is cleared at the end of the next buffer transfer.
• END_BF_ST: End of Channel Buffer Status
0: cleared automatically when read by software.
1: set by hardware when the BUFF_COUNT count-down reaches zero.
Valid until the CHANN_ENB flag is cleared at the end of the next buffer transfer.
31 30 29 28 27 26 25 24
BUFF_COUNT
23 22 21 20 19 18 17 16
BUFF_COUNT
15 14 13 12 11 10 9 8
––––––––
76543210
– DESC_LDST END_BF_ST END_TR_ST – – CHANN_ACT CHANN_ENB
AtmeL
1141
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• DESC_LDST: Descriptor Loaded Status
0: cleared automatically when read by software.
1: set by hardware when a descriptor has been loaded from the system bus.
Valid until the CHANN_ENB flag is cleared at the end of the next buffer transfer.
• BUFF_COUNT: Buffer Byte Count
This field determines the current number of bytes still to be transferred for this buffer.
This field is decremented from the AHB source bus access byte width at the end of this bus address phase.
The access byte width is 4 by default, or less, at DMA start or end, if the start or end address is not aligned on a word
boundary.
At the end of buffer, the DMA accesses the UOTGHS device only for the number of bytes needed to complete it.
Note: For OUT endpoints, if the receive buffer byte length (BUFF_LENGTH) has been defaulted to zero because the USB transfer
length is unknown, the actual buffer byte length received will be 0x10000-BUFF_COUNT.
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1142
39.6.3 USB Host Registers
39.6.3.1 Host General Control Register
Name: UOTGHS_HSTCTRL
Address: 0x400AC400
Access: Read-write
• SPDCONF: Mode Configuration
This field contains the host speed capability:.
• RESUME: Send USB Resume
Writing a one to this bit will generate a USB Resume on the USB bus.
This bit is cleared when the USB Resume has been sent or when a USB reset is requested.
Writing a zero to this bit has no effect.
This bit should be written to one only when the start of frame generation is enable. (SOFE bit is one).
• RESET: Send USB Reset
Writing a one to this bit will generate a USB Reset on the USB bus.
This bit is cleared when the USB Reset has been sent.
It may be useful to write a zero to this bit when a device disconnection is detected (UOTGHS_HSTISR.DDISCI is one)
whereas a USB Reset is being sent.
• SOFE: Start of Frame Generation Enable
Writing a one to this bit will generate SOF on the USB bus in full or high speed mode and keep alive in low speed mode.
Writing a zero to this bit will disable the SOF generation and to leave the USB bus in idle state.
This bit is set when a USB reset is requested or an upstream resume interrupt is detected (UOTGHS_HSTISR.TXRSMI).
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – SPDCONF – RESUME RESET SOFE
76543210
––––––––
Value Name Description
0NORMAL
The host starts in full-speed mode and performs a high-speed reset to switch to the high-
speed mode if the downstream peripheral is high-speed capable.
1 LOW_POWER For a better consumption, if high-speed is not needed.
2 HIGH_SPEED Forced high speed.
3 FORCED_FS The host remains to full-speed mode whatever the peripheral speed capability.
1143
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39.6.3.2 Host Global Interrupt Status Register
Name: UOTGHS_HSTISR
Address: 0x400AC404
Access: Read-only
• DMA_x: DMA Channel x Interrupt
This bit is set when an interrupt is triggered by the DMA channel x. This triggers a USB interrupt if the corresponding bit in
UOTGHS_HSTIMR is one.
This bit is cleared when the UOTGHS_HSTDMASTATUSx interrupt source is cleared.
• PEP_x: Pipe x Interrupt
This bit is set when an interrupt is triggered by the endpoint x (UOTGHS_HSTPIPISRx). This triggers a USB interrupt if the
corresponding bit in UOTGHS_HSTIMR is one.
This bit is cleared when the interrupt source is served.
• HWUPI: Host Wake-Up Interrupt
This bit is set when the host controller is in the suspend mode (SOFE is zero) and an upstream resume from the peripheral
is detected.
This bit is set when the host controller is in the suspend mode (SOFE is zero) and a peripheral disconnection is detected.
This bit is set when the host controller is in the Idle state (UOTGHS_SR.VBUSRQ is zero, no VBus is generated), and an
OTG SRP event initiated by the peripheral is detected (UOTGHS_SR.SRPI is one).
This interrupt is generated even if the clock is frozen by UOTGHS_CTRL.FRZCLK bit.
• HSOFI: Host Start of Frame Interrupt
This bit is set when a SOF is issued by the Host controller. This triggers a USB interrupt when HSOFE is one. When using
the host controller in low speed mode, this bit is also set when a keep-alive is sent.
This bit is cleared when UOTGHS_HSTICR.HSOFIC bit is written to one.
• RXRSMI: Upstream Resume Received Interrupt
This bit is set when an Upstream Resume has been received from the Device.
This bit is cleared when UOTGHS_HSTICR.RXRSMIC is written to one.
• RSMEDI: Downstream Resume Sent Interrupt
This bit set when a Downstream Resume has been sent to the Device.
This bit is cleared when UOTGHS_HSTICR.RSMEDIC bit is written to one.
31 30 29 28 27 26 25 24
– DMA_6 DMA_5 DMA_4 DMA_3 DMA_2 DMA_1 –
23 22 21 20 19 18 17 16
––––––PEP_9 PEP_8
15 14 13 12 11 10 9 8
PEP_7 PEP_6 PEP_5 PEP_4 PEP_3 PEP_2 PEP_1 PEP_0
76543210
– HWUPI HSOFI RXRSMI RSMEDI RSTI DDISCI DCONNI
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1144
• RSTI: USB Reset Sent Interrupt
This bit is set when a USB Reset has been sent to the device.
This bit is cleared when UOTGHS_HSTICR.RSTIC bit is written to one.
• DDISCI: Device Disconnection Interrupt
This bit is set when the device has been removed from the USB bus.
This bit is cleared when UOTGHS_HSTICR.DDISCIC bit is written to one.
• DCONNI: Device Connection Interrupt
This bit is set when a new device has been connected to the USB bus.
This bit is cleared when UOTGHS_HSTICR.DCONNIC bit is written to one.
1145
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39.6.3.3 Host Global Interrupt Clear Register
Name: UOTGHS_HSTICR
Address: 0x400AC408
Access: Write-only
• HWUPIC: Host Wake-Up Interrupt Clear
Writing a one to this bit will clear HWUPI bit in UOTGHS_HSTISR.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
• HSOFIC: Host Start of Frame Interrupt Clear
Writing a one to this bit will clear HSOFI bit in UOTGHS_HSTISR.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
• RXRSMIC: Upstream Resume Received Interrupt Clear
Writing a one to this bit will clear RXRSMI bit in UOTGHS_HSTISR.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
• RSMEDIC: Downstream Resume Sent Interrupt Clear
Writing a one to this bit will clear RSMEDI bit in UOTGHS_HSTISR.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
• RSTIC: USB Reset Sent Interrupt Clear
Writing a one to this bit will clear RSTI bit in UOTGHS_HSTISR.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
• DDISCIC: Device Disconnection Interrupt Clear
Writing a one to this bit will clear DDISCI bit in UOTGHS_HSTISR.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– HWUPIC HSOFIC RXRSMIC RSMEDIC RSTIC DDISCIC DCONNIC
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• DCONNIC: Device Connection Interrupt Clear
Writing a one to this bit will clear DCONNI bit in UOTGHS_HSTISR.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
1147
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39.6.3.4 Host Global Interrupt Set Register
Name: UOTGHS_HSTIFR
Address: 0x400AC40C
Access: Write-only
• DMA_x: DMA Channel x Interrupt Set
Writing a one to this bit will set the corresponding bit in UOTGHS_HSTISR, which may be useful for test or debug
purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HWUPIS: Host Wake-Up Interrupt Set
Writing a one to this bit will set HWUPI bit in UOTGHS_HSTISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HSOFIS: Host Start of Frame Interrupt Set
Writing a one to this bit will set HSOFI bit in UOTGHS_HSTISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXRSMIS: Upstream Resume Received Interrupt Set
Writing a one to this bit will set RXRSMI bit in UOTGHS_HSTISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RSMEDIS: Downstream Resume Sent Interrupt Set
Writing a one to this bit will set RSMEDI bit in UOTGHS_HSTISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RSTIS: USB Reset Sent Interrupt Set
Writing a one to this bit will set RSTI bit in UOTGHS_HSTISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
– DMA_6 DMA_5 DMA_4 DMA_3 DMA_2 DMA_1 –
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– HWUPIS HSOFIS RXRSMIS RSMEDIS RSTIS DDISCIS DCONNIS
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• DDISCIS: Device Disconnection Interrupt Set
Writing a one to this bit will set DDISCI bit in UOTGHS_HSTISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• DCONNIS: Device Connection Interrupt Set
Writing a one to this bit will set DCONNI bit in UOTGHS_HSTISR, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
1149
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39.6.3.5 Host Global Interrupt Mask Register
Name: UOTGHS_HSTIMR
Address: 0x400AC410
Access: Read-only
• DMA_x: DMA Channel x Interrupt Enable
This bit is set when the corresponding bit in UOTGHS_HSTIER is written to one. This will enable the DMA Channel x Inter-
rupt (UOTGHS_HSTISR.DMA_x).
This bit is cleared when the corresponding bit in UOTGHS_HSTIDR is written to one. This will disable the DMA Channel x
Interrupt (UOTGHS_HSTISR.DMA_x).
• PEP_x: Pipe x Interrupt Enable
This bit is set when the corresponding bit in UOTGHS_HSTIER is written to one. This will enable the Pipe x Interrupt
(UOTGHS_HSTISR.PEP_x).
This bit is cleared when the PEP_x bit is written to one. This will disable the Pipe x Interrupt (PEP_x).
• HWUPIE: Host Wake-Up Interrupt Enable
This bit is set when UOTGHS_HSTIER.HWUPIES bit is written to one. This will enable the Host Wake-up Interrupt
(UOTGHS_HSTISR.HWUPI).
This bit is cleared when UOTGHS_HSTIDR.HWUPIEC bit is written to one. This will disable the Host Wake-up Interrupt
(UOTGHS_HSTISR.HWUPI).
• HSOFIE: Host Start of Frame Interrupt Enable
This bit is set when UOTGHS_HSTIER.HSOFIES bit is written to one. This will enable the Host Start of Frame interrupt
(UOTGHS_HSTISR.HSOFI).
This bit is cleared when UOTGHS_HSTIDR.HSOFIEC bit is written to one. This will disable the Host Start of Frame inter-
rupt (UOTGHS_HSTISR.HSOFI).
• RXRSMIE: Upstream Resume Received Interrupt Enable
This bit is set when UOTGHS_HSTIER.RXRSMIES bit is written to one. This will enable the Upstream Resume Received
interrupt (UOTGHS_HSTISR.RXRSMI).
This bit is cleared when UOTGHS_HSTIDR.RXRSMIEC bit is written to one. This will disable the Downstream Resume
interrupt (UOTGHS_HSTISR.RXRSMI).
• RSMEDIE: Downstream Resume Sent Interrupt Enable
This bit is set when UOTGHS_HSTIER.RSMEDIES bit is written to one. This will enable the Downstream Resume interrupt
(UOTGHS_HSTISR.RSMEDI).
This bit is cleared when UOTGHS_HSTIDR.RSMEDIEC bit is written to one. This will disable the Downstream Resume
interrupt (UOTGHS_HSTISR.RSMEDI).
31 30 29 28 27 26 25 24
– DMA_6 DMA_5 DMA_4 DMA_3 DMA_2 DMA_1 –
23 22 21 20 19 18 17 16
––––––PEP_9 PEP_8
15 14 13 12 11 10 9 8
PEP_7 PEP_6 PEP_5 PEP_4 PEP_3 PEP_2 PEP_1 PEP_0
76543210
– HWUPIE HSOFIE RXRSMIE RSMEDIE RSTIE DDISCIE DCONNIE
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1150
• RSTIE: USB Reset Sent Interrupt Enable
This bit is set when UOTGHS_HSTIER.RSTIES bit is written to one. This will enable the USB Reset Sent interrupt
(UOTGHS_HSTISR.RSTI).
This bit is cleared when UOTGHS_HSTIDR.RSTIEC bit is written to one. This will disable the USB Reset Sent interrupt
(UOTGHS_HSTISR.RSTI).
• DDISCIE: Device Disconnection Interrupt Enable
This bit is set when UOTGHS_HSTIER.DDISCIES bit is written to one. This will enable the Device Disconnection interrupt
(UOTGHS_HSTISR.DDISCI).
This bit is cleared when UOTGHS_HSTIDR.DDISCIEC bit is written to one. This will disable the Device Disconnection
interrupt (UOTGHS_HSTISR.DDISCI).
• DCONNIE: Device Connection Interrupt Enable
This bit is set when UOTGHS_HSTIER.DCONNIES bit is written to one. This will enable the Device Connection interrupt
(UOTGHS_HSTISR.DCONNI).
This bit is cleared when UOTGHS_HSTIDR.DCONNIEC bit is written to one. This will disable the Device Connection inter-
rupt (UOTGHS_HSTISR.DCONNI).
1151
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39.6.3.6 Host Global Interrupt Disable Register
Name: UOTGHS_HSTIDR
Address: 0x400AC414
Access: Write-only
• DMA_x: DMA Channel x Interrupt Disable
Writing a one to this bit will clear the corresponding bit in UOTGHS_HSTIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• PEP_x: Pipe x Interrupt Disable
Writing a one to this bit will clear the corresponding bit in UOTGHS_HSTIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HWUPIEC: Host Wake-Up Interrupt Disable
Writing a one to this bit will clear HWUPIE bit in UOTGHS_HSTIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HSOFIEC: Host Start of Frame Interrupt Disable
Writing a one to this bit will clear HSOFIE bit in UOTGHS_HSTIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXRSMIEC: Upstream Resume Received Interrupt Disable
Writing a one to this bit will clear RXRSMIE bit in UOTGHS_HSTIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RSMEDIEC: Downstream Resume Sent Interrupt Disable
Writing a one to this bit will clear RSMEDIE bit in UOTGHS_HSTIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
– DMA_6 DMA_5 DMA_4 DMA_3 DMA_2 DMA_1 –
23 22 21 20 19 18 17 16
––––––PEP_9 PEP_8
15 14 13 12 11 10 9 8
PEP_7 PEP_6 PEP_5 PEP_4 PEP_3 PEP_2 PEP_1 PEP_0
76543210
– HWUPIEC HSOFIEC RXRSMIEC RSMEDIEC RSTIEC DDISCIEC DCONNIEC
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• RSTIEC: USB Reset Sent Interrupt Disable
Writing a one to this bit will clear RSTIE bit in UOTGHS_HSTIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• DDISCIEC: Device Disconnection Interrupt Disable
Writing a one to this bit will clear DDISCIE bit in UOTGHS_HSTIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• DCONNIEC: Device Connection Interrupt Disable
Writing a one to this bit will clear DCONNIE bit in UOTGHS_HSTIMR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
1153
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39.6.3.7 Host Global Interrupt Enable Register
Name: UOTGHS_HSTIER
Address: 0x400AC418
Access: Write-only
• DMA_x: DMA Channel x Interrupt Enable
Writing a one to this bit will set the corresponding bit in UOTGHS_HSTISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• PEP_x: Pipe x Interrupt Enable
Writing a one to this bit will set the corresponding bit in UOTGHS_HSTISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HWUPIES: Host Wake-Up Interrupt Enable
Writing a one to this bit will set HWUPI bit in UOTGHS_HSTISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• HSOFIES: Host Start of Frame Interrupt Enable
Writing a one to this bit will set HSOFI bit in UOTGHS_HSTISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXRSMIES: Upstream Resume Received Interrupt Enable
Writing a one to this bit will set RXRSMI bit in UOTGHS_HSTISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RSMEDIES: Downstream Resume Sent Interrupt Enable
Writing a one to this bit will set RSMEDI bit in UOTGHS_HSTISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
– DMA_6 DMA_5 DMA_4 DMA_3 DMA_2 DMA_1 –
23 22 21 20 19 18 17 16
––––––PEP_9 PEP_8
15 14 13 12 11 10 9 8
PEP_7 PEP_6 PEP_5 PEP_4 PEP_3 PEP_2 PEP_1 PEP_0
76543210
– HWUPIES HSOFIES RXRSMIES RSMEDIES RSTIES DDISCIES DCONNIES
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• RSTIES: USB Reset Sent Interrupt Enable
Writing a one to this bit will set RSTI bit in UOTGHS_HSTISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• DDISCIES: Device Disconnection Interrupt Enable
Writing a one to this bit will set DDISCI bit in UOTGHS_HSTISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• DCONNIES: Device Connection Interrupt Enable
Writing a one to this bit will set DCONNI bit in UOTGHS_HSTISR.
Writing a zero to this bit has no effect.
This bit always reads as zero.
1155
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39.6.3.8 Host Frame Number Register
Name: UOTGHS_HSTFNUM
Address: 0x400AC420
Access: Read-write
• FLENHIGH: Frame Length
In High speed mode, this field contains the 8 high-order bits of the 16-bit internal frame counter (at 30MHz, counter length
is 3750 to ensure a SOF generation every 125 us).
• FNUM: Frame Number
This field contains the current SOF number.
This field can be written. In this case, the MFNUM field is reset to zero.
• MFNUM: Micro Frame Number
This field contains the current Micro Frame number (can vary from 0 to 7) updated every 125us.
When operating in full-speed mode, this field is tied to zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FLENHIGH
15 14 13 12 11 10 9 8
– – FNUM
76543210
FNUM MFNUM
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1156
39.6.3.9 Host Address 1 Register
Name: UOTGHS_HSTADDR1
Address: 0x400AC424
Access: Read-write
• HSTADDRP3: USB Host Address
This field contains the address of the Pipe3 of the USB Device.
This field is cleared when a USB reset is requested.
• HSTADDRP2: USB Host Address
This field contains the address of the Pipe2 of the USB Device.
This field is cleared when a USB reset is requested.
• HSTADDRP1: USB Host Address
This field contains the address of the Pipe1 of the USB Device.
This field is cleared when a USB reset is requested.
• HSTADDRP0: USB Host Address
This field contains the address of the Pipe0 of the USB Device.
This field is cleared when a USB reset is requested.
31 30 29 28 27 26 25 24
– HSTADDRP3
23 22 21 20 19 18 17 16
– HSTADDRP2
15 14 13 12 11 10 9 8
– HSTADDRP1
76543210
– HSTADDRP0
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39.6.3.10 Host Address 2 Register
Name: UOTGHS_HSTADDR2
Address: 0x400AC428
Access: Read-write
• HSTADDRP7: USB Host Address
This field contains the address of the Pipe7 of the USB Device.
This field is cleared when a USB reset is requested.
• HSTADDRP6: USB Host Address
This field contains the address of the Pipe6 of the USB Device.
This field is cleared when a USB reset is requested.
• HSTADDRP5: USB Host Address
This field contains the address of the Pipe5 of the USB Device.
This field is cleared when a USB reset is requested.
• HSTADDRP4: USB Host Address
This field contains the address of the Pipe4 of the USB Device.
This field is cleared when a USB reset is requested.
31 30 29 28 27 26 25 24
– HSTADDRP7
23 22 21 20 19 18 17 16
– HSTADDRP6
15 14 13 12 11 10 9 8
– HSTADDRP5
76543210
– HSTADDRP4
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1158
39.6.3.11 Host Address 3 Register
Name: UOTGHS_HSTADDR3
Address: 0x400AC42C
Access: Read-write
• HSTADDRP9: USB Host Address
This field contains the address of the Pipe9 of the USB Device.
This field is cleared when a USB reset is requested.
• HSTADDRP8: USB Host Address
This field contains the address of the Pipe8 of the USB Device.
This field is cleared when a USB reset is requested.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– HSTADDRP9
76543210
– HSTADDRP8
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39.6.3.12 Host Pipe Register
Name: UOTGHS_HSTPIP
Address: 0x400AC41C
Access: Read-write
•PRSTx: Pipe x Reset
Writing a one to this bit will reset the Pipe x FIFO.
This resets the endpoint x registers (UOTGHS_HSTPIPCFGx, UOTGHS_HSTPIPISRx, UOTGHS_HSTPIPIMRx) but not
the endpoint configuration (ALLOC, PBK, PSIZE, PTOKEN, PTYPE, PEPNUM, INTFRQ).
All the endpoint mechanism (FIFO counter, reception, transmission, etc.) is reset apart from the Data Toggle management.
The endpoint configuration remains active and the endpoint is still enabled.
Writing a zero to this bit will complete the reset operation and allow to start using the FIFO.
• PENx: Pipe x Enable
Writing a one to this bit will enable the Pipe x.
Writing a zero to this bit will disable the Pipe x, which forces the Pipe x state to inactive and resets the pipe x registers
(UOTGHS_HSTPIPCFGx, UOTGHS_HSTPIPISRx, UOTGHS_HSTPIPIMRx) but not the pipe configuration
(UOTGHS_HSTPIPCFGx.ALLOC, UOTGHS_HSTPIPCFGx.PBK, UOTGHS_HSTPIPCFGx.PSIZE).
31 30 29 28 27 26 25 24
–––––––PRST8
23 22 21 20 19 18 17 16
PRST7 PRST6 PRST5 PRST4 PRST3 PRST2 PRST1 PRST0
15 14 13 12 11 10 9 8
–––––––PEN8
76543210
PEN7 PEN6 PEN5 PEN4 PEN3 PEN2 PEN1 PEN0
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1160
39.6.3.13 Host Pipe x Configuration Register
Name: UOTGHS_HSTPIPCFGx [x=0..9]
Address: 0x400AC500
Access: Read-write
• INTFRQ: Pipe Interrupt Request Frequency
This field contains the maximum value in millisecond of the polling period for an Interrupt Pipe.
This value has no effect for a non-Interrupt Pipe.
This field is cleared upon sending a USB reset.
• BINTERVAL: bInterval parameter for the Bulk-Out/Ping transaction
This field contains the Ping/Bulk-out period.
• If BINTERVAL>0 and PINGEN=1, one PING token is sent every BINTERVAL micro-frame until it is ACKed by the
peripheral.
• If BINTERVAL=0 and PINGEN=1, multiple consecutive PING token is sent in the same micro-frame until it is ACKed.
• If BINTERVAL>0 and PINGEN=0, one OUT token is sent every BINTERVAL micro-frame until it is ACKed by the
peripheral.
• If BINTERVAL=0 and PINGEN=0, multiple consecutive OUT token is sent in the same micro-frame until it is ACKed.
This value must be in the range from 0 to 255.
• PINGEN: Ping Enable
This bit is relevant for High-speed Bulk-out transaction only (including the control data stage and the control status stage).
Writing a zero to this bit will disable the ping protocol.
Writing a one to this bit will enable the ping mechanism according to the USB 2.0 standard.
This bit is cleared upon sending a USB reset.
•PEPNUM: Pipe Endpoint Number
This field contains the number of the endpoint targeted by the pipe. This value is from 0 to 10.
This field is cleared upon sending a USB reset.
31 30 29 28 27 26 25 24
INTFRQ/BINTERVAL
23 22 21 20 19 18 17 16
– – – PINGEN PEPNUM
15 14 13 12 11 10 9 8
– – PTYPE – AUTOSW PTOKEN
76543210
– PSIZE PBK ALLOC –
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• PTYPE: Pipe Type
This field contains the pipe type.
This field is cleared upon sending a USB reset.
• AUTOSW: Automatic Switch
This bit is cleared upon sending a USB reset.
0: The automatic bank switching is disabled.
1: The automatic bank switching is enabled.
• PTOKEN: Pipe Token
This field contains the endpoint token.
• PSIZE: Pipe Size
This field contains the size of each pipe bank.
This field is cleared upon sending a USB reset.
Value Name Description
0CTRLControl
1 ISO Isochronous
2BLKBulk
3 INTRPT Interrupt
Value Name Description
0 SETUP SETUP
1IN IN
2OUT OUT
3 reserved
Value Name Description
0 8_BYTE 8 bytes
1 16_BYTE 16 bytes
2 32_BYTE 32 bytes
3 64_BYTE 64 bytes
4 128_BYTE 128 bytes
5 256_BYTE 256 bytes
6 512_BYTE 512 bytes
7 1024_BYTE 1024 bytes
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•PBK: Pipe Banks
This field contains the number of banks for the pipe.
For control endpoints, a single-bank pipe (0b00) should be selected.
This field is cleared upon sending a USB reset.
• ALLOC: Pipe Memory Allocate
Writing a one to this bit will allocate the pipe memory.
Writing a zero to this bit will free the pipe memory.
This bit is cleared when a USB Reset is requested.
Refer to the DPRAM Management chapter for more details.
Value Name Description
0 1_BANK Single-bank pipe
1 2_BANK Double-bank pipe
2 3_BANK Triple-bank pipe
3 Reserved
1163
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.3.14 Host Pipe x Status Register
Name: UOTGHS_HSTPIPISRx [x=0..9]
Address: 0x400AC530
Access: Read-only
• PBYCT: Pipe Byte Count
This field contains the byte count of the FIFO.
For OUT pipe, incremented after each byte written by the user into the pipe and decremented after each byte sent to the
peripheral.
For IN pipe, incremented after each byte received from the peripheral and decremented after each byte read by the user
from the pipe.
This field may be updated 1 clock cycle after the RWALL bit changes, so the user should not poll this field as an interrupt
bit.
• CFGOK: Configuration OK Status
This bit is set/cleared when the UOTGHS_HSTPIPCFGx.ALLOC bit is set.
This bit is set if the pipe x number of banks (UOTGHS_HSTPIPCFGx.PBK) and size (UOTGHS_HSTPIPCFGx.PSIZE) are
correct compared to the maximal allowed number of banks and size for this pipe and to the maximal FIFO size (i.e., the
DPRAM size).
If this bit is cleared, the user should rewrite correct values of the PBK and PSIZE field in the UOTGHS_HSTPIPCFGx
register.
• RWALL: Read-write Allowed
For OUT pipe, this bit is set when the current bank is not full, i.e., the software can write further data into the FIFO.
For IN pipe, this bit is set when the current bank is not empty, i.e., the software can read further data from the FIFO.
This bit is cleared otherwise.
This bit is also cleared when the RXSTALLDI or the PERRI bit is one.
31 30 29 28 27 26 25 24
– PBYCT
23 22 21 20 19 18 17 16
PBYCT – CFGOK – RWALL
15 14 13 12 11 10 9 8
CURRBK NBUSYBK – – DTSEQ
76543210
SHORTPACKET
IRXSTALLDI/
CRCERRI OVERFI NAKEDI PERRI TXSTPI/
UNDERFI TXOUTI RXINI
AtmeL
SAM3X / SAM3A [DATASHEET]
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1164
• CURRBK: Current Bank
For non-control pipe, this field indicates the number of the current bank.
This field may be updated 1 clock cycle after the RWALL bit changes, so the user shall not poll this field as an interrupt bit.
• NBUSYBK: Number of Busy Banks
This field indicates the number of busy banks.
For OUT pipe, this field indicates the number of busy banks, filled by the user, ready for OUT transfer. When all banks are
busy, this triggers a PEP_x interrupt if UOTGHS_HSTPIPIMRx.NBUSYBKE is one.
For IN pipe, this field indicates the number of busy banks filled by IN transaction from the Device. When all banks are free,
this triggers a PEP_x interrupt if UOTGHS_HSTPIPIMRx.NBUSYBKE is one.
• DTSEQ: Data Toggle Sequence
This field indicates the data PID of the current bank.
For OUT pipe, this field indicates the data toggle of the next packet that will be sent.
For IN pipe, this field indicates the data toggle of the received packet stored in the current bank.
• SHORTPACKETI: Short Packet Interrupt
This bit is set when a short packet is received by the host controller (packet length inferior to the PSIZE programmed field).
This bit is cleared when UOTGHS_HSTPIPICR.SHORTPACKETIC bit is written to one.
• RXSTALLDI: Received STALLed Interrupt
This bit is set, for all endpoints but isochronous, when a STALL handshake has been received on the current bank of the
pipe. The Pipe is automatically frozen. This triggers an interrupt if UOTGHS_HSTPIPIMR.RXSTALLE bit is one.
This bit is cleared when UOTGHS_HSTPIPICR.RXSTALLDIC bit is written to one.
Value Name Description
0 BANK0 Current bank is bank0
1 BANK1 Current bank is bank1
2 BANK2 Current bank is bank2
3 Reserved
Value Name Description
0 0_BUSY 0 busy bank (all banks free)
1 1_BUSY 1 busy bank
2 2_BUSY 2 busy banks
3 3_BUSY 3 busy banks
Value Name Description
0 DATA0 Data0 toggle sequence
1 DATA1 Data1 toggle sequence
2 reserved
3 reserved
AtmeL
1165
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• CRCERRI: CRC Error Interrupt
This bit is set, for isochronous endpoint, when a CRC error occurs on the current bank of the Pipe. This triggers an inter-
rupt if UOTGHS_HSTPIPIMR.TXSTPE bit is one.
This bit is cleared when UOTGHS_HSTPIPICR.CRCERRIC bit is written to one.
• OVERFI: Overflow Interrupt
This bit is set when the current pipe has received more data than the maximum length of the current pipe. An interrupt is
triggered if UOTGHS_HSTPIPIMR.OVERFIE bit is one.
This bit is cleared when UOTGHS_HSTPIPICR.OVERFIC bit is written to one.
• NAKEDI: NAKed Interrupt
This bit is set when a NAK has been received on the current bank of the pipe. This triggers an interrupt if
UOTGHS_HSTPIPIMR.NAKEDE bit is one.
This bit is cleared when UOTGHS_HSTPIPICR.NAKEDIC bit written to one.
• PERRI: Pipe Error Interrupt
This bit is set when an error occurs on the current bank of the pipe. This triggers an interrupt if
UOTGHS_HSTPIPIMR.PERRE bit is set. Refer to the UOTGHS_HSTPIPERRx register to determine the source of the
error.
This bit is cleared when the error source bit is cleared.
• TXSTPI: Transmitted SETUP Interrupt
This bit is set, for Control endpoints, when the current SETUP bank is free and can be filled. This triggers an interrupt if
UOTGHS_HSTPIPIMR.TXSTPE bit is one.
This bit is cleared when UOTGHS_HSTPIPICR.TXSTPIC bit is written to one.
• UNDERFI: Underflow Interrupt
This bit is set, for isochronous and Interrupt IN/OUT pipe, when an error flow occurs. This triggers an interrupt if the
UNDERFIE bit is one.
This bit is set, for Isochronous or interrupt OUT pipe, when a transaction underflow occurs in the current pipe. (The pipe
cannot send the OUT data packet in time because the current bank is not ready). A zero-length-packet (ZLP) will be sent
instead.
This bit is set, for Isochronous or interrupt IN pipe, when a transaction flow error occurs in the current pipe. i.e, the current
bank of the pipe is not free whereas a new IN USB packet is received. This packet is not stored in the bank. For Interrupt
pipe, the overflowed packet is ACKed to respect the USB standard.
This bit is cleared when UOTGHS_HSTPIPICR.UNDERFIEC bit is written to one.
• TXOUTI: Transmitted OUT Data Interrupt
This bit is set when the current OUT bank is free and can be filled. This triggers an interrupt if
UOTGHS_HSTPIPIMR.TXOUTE bit is one.
This bit is cleared when UOTGHS_HSTPIPICR.TXOUTIC bit is written to one.
• RXINI: Received IN Data Interrupt
This bit is set when a new USB message is stored in the current bank of the pipe. This triggers an interrupt if
UOTGHS_HSTPIPIMR.RXINE bit is one.
This bit is cleared when UOTGHS_HSTPIPICR.RXINIC bit is written to one.
AtmeL
SAM3X / SAM3A [DATASHEET]
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1166
39.6.3.15 Host Pipe x Clear Register
Name: UOTGHS_HSTPIPICRx [x=0..9]
Address: 0x400AC560
Access: Write-only
• SHORTPACKETIC: Short Packet Interrupt Clear
Writing a one to this bit will clear SHORTPACKETI bit in UOTGHS_HSTPIPISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXSTALLDIC: Received STALLed Interrupt Clear
Writing a one to this bit will clear RXSTALLDI bit in UOTGHS_HSTPIPISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• CRCERRIC: CRC Error Interrupt Clear
Writing a one to this bit will clear CRCERRI bit in UOTGHS_HSTPIPISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• OVERFIC: Overflow Interrupt Clear
Writing a one to this bit will clear OVERFI bit in UOTGHS_HSTPIPISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKEDIC: NAKed Interrupt Clear
Writing a one to this bit will clear NAKEDI bit in UOTGHS_HSTPIPISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXSTPIC: Transmitted SETUP Interrupt Clear
Writing a one to this bit will clear TXSTPI bit in UOTGHS_HSTPIPISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
SHORT
PACKETIC RXSTALLDIC
/CRCERRIC OVERFIC NAKEDIC – TXSTPIC/
UNDERFIC TXOUTIC RXINIC
AtmeL
1167
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• UNDERFIC: Underflow Interrupt Clear
Writing a one to this bit will clear UNDERFI bit in UOTGHS_HSTPIPISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXOUTIC: Transmitted OUT Data Interrupt Clear
Writing a one to this bit will clear TXOUTI bit in UOTGHS_HSTPIPISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXINIC: Received IN Data Interrupt Clear
Writing a one to this bit will clear RXINI bit in UOTGHS_HSTPIPISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1168
39.6.3.16 Host Pipe x Set Register
Name: UOTGHS_HSTPIPIFRx [x=0..9]
Address: 0x400AC590
Access: Write-only
• NBUSYBKS: Number of Busy Banks Set
Writing a one to this bit will set NBUSYBK bit in UOTGHS_HSTPIPISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SHORTPACKETIS: Short Packet Interrupt Set
Writing a one to this bit will set SHORTPACKETI bit in UOTGHS_HSTPIPISRx, which may be useful for test or debug
purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXSTALLDIS: Received STALLed Interrupt Set
Writing a one to this bit will set RXSTALLDI bit in UOTGHS_HSTPIPISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• CRCERRIS: CRC Error Interrupt Set
Writing a one to this bit will set CRCERRI bit in UOTGHS_HSTPIPISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• OVERFIS: Overflow Interrupt Set
Writing a one to this bit will set OVERFI bit in UOTGHS_HSTPIPISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKEDIS: NAKed Interrupt Set
Writing a one to this bit will set NAKEDI bit in UOTGHS_HSTPIPISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – – NBUSYBKS ––––
76543210
SHORT
PACKETIS
RXSTALLDIS/
CRCERRIS OVERFIS NAKEDIS PERRIS TXSTPIS/
UNDERFIS TXOUTIS RXINIS
AtmeL
1169
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• PERRIS: Pipe Error Interrupt Set
Writing a one to this bit will set PERRI bit in UOTGHS_HSTPIPISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXSTPIS: Transmitted SETUP Interrupt Set
Writing a one to this bit will set TXSTPI bit in UOTGHS_HSTPIPISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• UNDERFIS: Underflow Interrupt Set
Writing a one to this bit will set UNDERFI bit in UOTGHS_HSTPIPISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXOUTIS: Transmitted OUT Data Interrupt Set
Writing a one to this bit will set TXOUTI bit in UOTGHS_HSTPIPISRx, which may be useful for test or debug purposes.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXINIS: Received IN Data Interrupt Set
Writing a one to this bit will set RXINI bit in UOTGHS_HSTPIPISRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
AtmeL
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1170
39.6.3.17 Host Pipe x Mask Register
Name: UOTGHS_HSTPIPIMRx [x=0..9]
Address: 0x400AC5C0
Access: Read-only
• RSTDT: Reset Data Toggle
This bit is set when UOTGHS_HSTPIPIER.RSTDTS bit is written to one. This will reset the Data Toggle to its initial value
for the current Pipe.
This bit is cleared when proceed.
• PFREEZE: Pipe Freeze
This bit is set when UOTGHS_HSTPIPIER.PFREEZES bit is written to one or when the pipe is not configured or when a
STALL handshake has been received on this Pipe or when an error occurs on the Pipe (UOTGHS_HSTPIPISR.PERRI is
one) or when (INRQ+1) In requests have been processed or when after a Pipe reset (UOTGHS_HSTPIP.PRSTx rising) or
a Pipe Enable (UOTGHS_HSTPIP.PEN rising). This will Freeze the Pipe requests generation.
This bit is cleared when UOTGHS_HSTPIPIDR.PFREEZEC bit is written to one. This will enable the Pipe request
generation.
• PDISHDMA: Pipe Interrupts Disable HDMA Request Enable
See the UOTGHS_DEVEPTIMR.EPDISHDMA bit description.
• FIFOCON: FIFO Control
For OUT and SETUP Pipe:
This bit is set when the current bank is free, at the same time than UOTGHS_HSTPIPISR.TXOUTI or TXSTPI.
This bit is cleared when UOTGHS_HSTPIPIDR.FIFOCONC bit is written to one. This will send the FIFO data and
switch the bank.
For IN Pipe:
This bit is set when a new IN message is stored in the current bank, at the same time than
UOTGHS_HSTPIPISR.RXINI.
This bit is cleared when UOTGHS_HSTPIPIDR.FIFOCONC bit is written to one. This will free the current bank and
switch to the next bank.
• NBUSYBKE: Number of Busy Banks Interrupt Enable
This bit is set when UOTGHS_HSTPIPIER.NBUSYBKES bit is written to one.This will enable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.NBUSYBKE).
This bit is cleared when UOTGHS_HSTPIPIDR.NBUSYBKEC bit is written to one. This will disable the Transmitted IN
Data interrupt (UOTGHS_HSTPIPIMR.NBUSYBKE).
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––RSTDTPFREEZEPDISHDMA
15 14 13 12 11 10 9 8
– FIFOCON – NBUSYBKE ––––
76543210
SHORT
PACKETIE RXSTALLDE/
CRCERRE OVERFIE NAKEDE PERRE TXSTPE/
UNDERFIE TXOUTE RXINE
AtmeL
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• SHORTPACKETIE: Short Packet Interrupt Enable
If this bit is set for non-control OUT pipes, a short packet transmission is guaranteed upon ending a DMA transfer, thus sig-
naling an end of transfer, provided that the End of DMA Buffer Output Enable
(UOTGHS_HSTDMACONTROL.END_B_EN) bit and the Automatic Switch (UOTGHS_HSTPIPCFG.AUTOSW) bit are
written to one.
This bit is set when UOTGHS_HSTPIPIER.SHORTPACKETIES bit is written to one. This will enable the Transmitted IN
Data IT (UOTGHS_HSTPIPIMR.SHORTPACKETIE).
This bit is cleared when UOTGHS_HSTPIPIDR.SHORTPACKETEC bit is written to one. This will disable the Transmitted
IN Data IT (UOTGHS_HSTPIPIMR.SHORTPACKETE).
• RXSTALLDE: Received STALLed Interrupt Enable
This bit is set when UOTGHS_HSTPIPIER.RXSTALLDES bit is written to one. This will enable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.RXSTALLDE).
This bit is cleared when UOTGHS_HSTPIPIDR.RXSTALLDEC bit is written to one. This will disable the Transmitted IN
Data interrupt (UOTGHS_HSTPIPIMR.RXSTALLDE).
• CRCERRE: CRC Error Interrupt Enable
This bit is set when UOTGHS_HSTPIPIER.CRCERRES bit is written to one. This will enable the Transmitted IN Data inter-
rupt (UOTGHS_HSTPIPIMR.CRCERRE).
This bit is cleared when UOTGHS_HSTPIPIDR.CRCERREC bit is written to one. This will disable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.CRCERRE).
• OVERFIE: Overflow Interrupt Enable
This bit is set when UOTGHS_HSTPIPIER.OVERFIES bit is written to one. This will enable the Transmitted IN Data inter-
rupt (UOTGHS_HSTPIPIMR.OVERFIE).
This bit is cleared when UOTGHS_HSTPIPIDR.OVERFIEC bit is written to one. This will disable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.OVERFIE).
• NAKEDE: NAKed Interrupt Enable
This bit is set when UOTGHS_HSTPIPIER.NAKEDES bit is written to one. This will enable the Transmitted IN Data inter-
rupt (UOTGHS_HSTPIPIMR.NAKEDE).
This bit is cleared when UOTGHS_HSTPIPIDR.NAKEDEC bit is written to one. This will disable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.NAKEDE).
• PERRE: Pipe Error Interrupt Enable
This bit is set when UOTGHS_HSTPIPIER.PERRES bit is written to one. This will enable the Transmitted IN Data interrupt
(UOTGHS_HSTPIPIMR.PERRE).
This bit is cleared when UOTGHS_HSTPIPIDR.PERREC bit is written to one. This will disable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.PERRE).
• TXSTPE: Transmitted SETUP Interrupt Enable
This bit is set when UOTGHS_HSTPIPIER.TXSTPES bit is written to one. This will enable the Transmitted IN Data inter-
rupt (UOTGHS_HSTPIPIMR.TXSTPE).
This bit is cleared when UOTGHS_HSTPIPIDR.TXSTPEC bit is written to one. This will disable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.TXSTPE).
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1172
• UNDERFIE: Underflow Interrupt Enable
This bit is set when UOTGHS_HSTPIPIER.UNDERFIES bit is written to one. This will enable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.UNDERFIE).
This bit is cleared when UOTGHS_HSTPIPIDR.UNDERFIEC bit is written to one. This will disable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.UNDERFIE).
• TXOUTE: Transmitted OUT Data Interrupt Enable
This bit is set when UOTGHS_HSTPIPIER.TXOUTES bit is written to one. This will enable the Transmitted IN Data inter-
rupt (UOTGHS_HSTPIPIMR.TXOUTE).
This bit is cleared when UOTGHS_HSTPIPIDR.TXOUTEC bit is written to one. This will disable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.TXOUTE).
• RXINE: Received IN Data Interrupt Enable
This bit is set when UOTGHS_HSTPIPIER.RXINES bit is written to one. This will enable the Transmitted IN Data interrupt
(UOTGHS_HSTPIPIMR.RXINE).
This bit is cleared when UOTGHS_HSTPIPIDR.RXINEC bit is written to one. This will disable the Transmitted IN Data
interrupt (UOTGHS_HSTPIPIMR.RXINE).
AtmeL
1173
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.3.18 Host Pipe x Disable Register
Name: UOTGHS_HSTPIPIDRx [x=0..9]
Address: 0x400AC620
Access: Write-only
• PFREEZEC: Pipe Freeze Disable
Writing a one to this bit will clear PFREEZE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• PDISHDMAC: Pipe Interrupts Disable HDMA Request Disable
Writing a one to this bit will clear PDISHDMA bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• FIFOCONC: FIFO Control Disable
Writing a one to this bit will clear FIFOCON bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NBUSYBKEC: Number of Busy Banks Disable
Writing a one to this bit will clear NBUSYBKE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SHORTPACKETIEC: Short Packet Interrupt Disable
Writing a one to this bit will clear SHORTPACKETIE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXSTALLDEC: Received STALLed Interrupt Disable
Writing a one to this bit will clear RXSTALLDE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––PFREEZECPDISHDMAC
15 14 13 12 11 10 9 8
– FIFOCONC – NBUSYBKEC ––––
76543210
SHORT
PACKETIEC RXSTALLDEC/
CRCERREC OVERFIEC NAKEDEC PERREC TXSTPEC/
UNDERFIEC TXOUTEC RXINEC
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1174
• CRCERREC: CRC Error Interrupt Disable
Writing a one to this bit will clear CRCERRE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• OVERFIEC: Overflow Interrupt Disable
Writing a one to this bit will clear OVERFIE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKEDEC: NAKed Interrupt Disable
Writing a one to this bit will clear NAKEDE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• PERREC: Pipe Error Interrupt Disable
Writing a one to this bit will clear PERRE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXSTPEC: Transmitted SETUP Interrupt Disable
Writing a one to this bit will clear TXSTPE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• UNDERFIEC: Underflow Interrupt Disable
Writing a one to this bit will clear UNDERFIE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXOUTEC: Transmitted OUT Data Interrupt Disable
Writing a one to this bit will clear TXOUTE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXINEC: Received IN Data Interrupt Disable
Writing a one to this bit will clear RXINI bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
AtmeL
1175
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.6.3.19 Host Pipe x Enable Register
Name: UOTGHS_HSTPIPIERx [x=0..9]
Address: 0x400AC5F0
Access: Write-only
• RSTDTS: Reset Data Toggle Enable
Writing a one to this bit will set RSTDT bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• PFREEZES: Pipe Freeze Enable
Writing a one to this bit will set PFREEZE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• PDISHDMAS: Pipe Interrupts Disable HDMA Request Enable
Writing a one to this bit will set PDISHDMA bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NBUSYBKES: Number of Busy Banks Enable
Writing a one to this bit will set NBUSYBKE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• SHORTPACKETIES: Short Packet Interrupt Enable
Writing a one to this bit will set SHORTPACKETIE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXSTALLDES: Received STALLed Interrupt Enable
Writing a one to this bit will set RXSTALLDE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––RSTDTSPFREEZESPDISHDMAS
15 14 13 12 11 10 9 8
– – – NBUSYBKES ––––
76543210
SHORT
PACKETIES RXSTALLDES/
CRCERRES OVERFIES NAKEDES PERRES TXSTPES/
UNDERFIES TXOUTES RXINES
AtmeL
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1176
• CRCERRES: CRC Error Interrupt Enable
Writing a one to this bit will set CRCERRE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• OVERFIES: Overflow Interrupt Enable
Writing a one to this bit will set OVERFIE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• NAKEDES: NAKed Interrupt Enable
Writing a one to this bit will set NAKEDE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• PERRES: Pipe Error Interrupt Enable
Writing a one to this bit will set PERRE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXSTPES: Transmitted SETUP Interrupt Enable
Writing a one to this bit will set TXSTPE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• UNDERFIES: Underflow Interrupt Enable
Writing a one to this bit will set UNDERFIE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• TXOUTES: Transmitted OUT Data Interrupt Enable
Writing a one to this bit will set TXOUTE bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• RXINES: Received IN Data Interrupt Enable
Writing a one to this bit will set RXINI bit in UOTGHS_HSTPIPIMRx.
Writing a zero to this bit has no effect.
This bit always reads as zero.
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39.6.3.20 Host Pipe x IN Request Register
Name: UOTGHS_HSTPIPINRQx [x=0..9]
Address: 0x400AC650
Access: Read-write
• INMODE: IN Request Mode
Writing a one to this bit will allow the UOTGHS to perform infinite IN requests when the Pipe is not frozen.
Writing a zero to this bit will perform a pre-defined number of IN requests. This number is the INRQ field.
• INRQ: IN Request Number before Freeze
This field contains the number of IN transactions before the UOTGHS freezes the pipe. The UOTGHS will perform
(INRQ+1) IN requests before to freeze the Pipe. This counter is automatically decreased by 1 each time a IN request has
been successfully performed.
This register has no effect when the INMODE bit is one (infinite IN requests generation till the pipe is not frozen).
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––––INMODE
76543210
INRQ
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39.6.3.21 Host Pipe x Error Register
Name: UOTGHS_HSTPIPERRx [x=0..9]
Address: 0x400AC680
Access: Read-write
• COUNTER: Error Counter
This field is incremented each time an error occurs (CRC16, TIMEOUT, PID, DATAPID or DATATGL).
This field is cleared when receiving a good USB packet without any error.
When this field reaches 3 (i.e., 3 consecutive errors), this pipe is automatically frozen (UOTGHS_HSTPIPIMRx.PFREEZE
is set).
Writing 0b00 to this field will clear the counter.
• CRC16: CRC16 Error
This bit is set when a CRC16 error has been detected.
Writing a zero to this bit will clear the bit.
Writing a one to this bit has no effect.
• TIMEOUT: Time-Out Error
This bit is set when a Time-Out error has been detected.
Writing a zero to this bit will clear the bit.
Writing a one to this bit has no effect.
• PID: PID Error
This bit is set when a PID error has been detected.
Writing a zero to this bit will clear the bit.
Writing a one to this bit has no effect.
• DATAPID: Data PID Error
This bit is set when a Data PID error has been detected.
Writing a zero to this bit will clear the bit.
Writing a one to this bit has no effect.
• DATATGL: Data Toggle Error
This bit is set when a Data Toggle error has been detected.
Writing a zero to this bit will clear the bit.
Writing a one to this bit has no effect.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– COUNTER CRC16 TIMEOUT PID DATAPID DATATGL
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39.6.3.22 Host DMA Channel x Next Descriptor Address Register
Name: UOTGHS_HSTDMANXTDSCx [x=1..6]
Address: 0x400AC710 [1], 0x400AC720 [2], 0x400AC730 [3], 0x400AC740 [4], 0x400AC750 [5], 0x400AC760 [6],
0x400AC770 [7]
Access: Read-write
• NXT_DSC_ADD: Next Descriptor Address
This field points to the next channel descriptor to be processed. This channel descriptor must be aligned, so bits 0 to 3 of
the address must be equal to zero.
31 30 29 28 27 26 25 24
NXT_DSC_ADD
23 22 21 20 19 18 17 16
NXT_DSC_ADD
15 14 13 12 11 10 9 8
NXT_DSC_ADD
76543210
NXT_DSC_ADD
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39.6.3.23 Host DMA Channel x Address Register
Name: UOTGHS_HSTDMAADDRESSx [x=1..6]
Address: 0x400AC714 [1], 0x400AC724 [2], 0x400AC734 [3], 0x400AC744 [4], 0x400AC754 [5], 0x400AC764 [6],
0x400AC774 [7]
Access: Read-write
• BUFF_ADD: Buffer Address
This field determines the AHB bus starting address of a DMA channel transfer.
Channel start and end addresses may be aligned on any byte boundary.
The firmware may write this field only when the UOTGHS_HSTDMASTATUS.CHANN_ENB bit is clear.
This field is updated at the end of the address phase of the current access to the AHB bus. It is incrementing of the access
byte width. The access width is 4 bytes (or less) at packet start or end, if the start or end address is not aligned on a word
boundary.
The packet start address is either the channel start address or the next channel address to be accessed in the channel
buffer.
The packet end address is either the channel end address or the latest channel address accessed in the channel buffer.
The channel start address is written by software or loaded from the descriptor, whereas the channel end address is either
determined by the end of buffer or the USB device, USB end of transfer if the
UOTGHS_HSTDMACONTROLx.END_TR_EN bit is set.
31 30 29 28 27 26 25 24
BUFF_ADD
23 22 21 20 19 18 17 16
BUFF_ADD
15 14 13 12 11 10 9 8
BUFF_ADD
76543210
BUFF_ADD
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39.6.3.24 Host DMA Channel x Control Register
Name: UOTGHS_HSTDMACONTROLx [x=1..6]
Address: 0x400AC718 [1], 0x400AC728 [2], 0x400AC738 [3], 0x400AC748 [4], 0x400AC758 [5], 0x400AC768 [6],
0x400AC778 [7]
Access: Read-write
• CHANN_ENB: Channel Enable Command
0: DMA channel is disabled and no transfer will occur upon request. This bit is also cleared by hardware when the channel
source bus is disabled at the end of buffer.
If LDNXT_DSC bit has been cleared by descriptor loading, the firmware will have to set the corresponding CHANN_ENB
bit to start the described transfer, if needed.
If LDNXT_DSC bit is cleared, the channel is frozen and the channel registers may then be read and/or written reliably as
soon as both UOTGHS_HSTDMASTATUS.CHANN_ENB and CHANN_ACT flags read as 0.
If a channel request is currently serviced when this bit is cleared, the DMA FIFO buffer is drained until it is empty, then
UOTGHS_HSTDMASTATUS.CHANN_ENB bit is cleared.
If LDNXT_DSC bit is set or after this bit clearing, then the currently loaded descriptor is skipped (no data transfer occurs)
and the next descriptor is immediately loaded.
1: UOTGHS_HSTDMASTATUS.CHANN_ENB bit will be set, thus enabling DMA channel data transfer. Then any pending
request will start the transfer. This may be used to start or resume any requested transfer.
• LDNXT_DSC: Load Next Channel Transfer Descriptor Enable Command
0: no channel register is loaded after the end of the channel transfer.
1: the channel controller loads the next descriptor after the end of the current transfer, i.e. when the
UOTGHS_HSTDMASTATUS.CHANN_ENB bit is reset.
If CHANN_ENB bit is cleared, the next descriptor is immediately loaded upon transfer request.
DMA Channel Control Command Summary
31 30 29 28 27 26 25 24
BUFF_LENGTH
23 22 21 20 19 18 17 16
BUFF_LENGTH
15 14 13 12 11 10 9 8
––––––––
76543210
BURST_LCK DESC_LD_IT END_BUFFIT END_TR_IT END_B_EN END_TR_EN LDNXT_DSC CHANN_ENB
Value Name Description
0STOP_NOW Stop now
1 RUN_AND_STOP Run and stop at end of buffer
2 LOAD_NEXT_DESC Load next descriptor now
3 RUN_AND_LINK Run and link at end of buffer
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• END_TR_EN: End of Transfer Enable (Control)
Used for OUT transfers only.
0: USB end of transfer is ignored.
1: UOTGHS device can put an end to the current buffer transfer.
When set, a BULK or INTERRUPT short packet will close the current buffer and the
UOTGHS_HSTDMASTATUSx.END_TR_ST flag will be raised.
This is intended for a UOTGHS non-prenegotiated end of transfer (BULK or INTERRUPT) data buffer closure.
• END_B_EN: End of Buffer Enable Control
0: DMA Buffer End has no impact on USB packet transfer.
1: the pipe can validate the packet (according to the values programmed in the UOTGHS_HSTPIPCFGx.AUTOSW field,
and in the UOTGHS_HSTPIPIMRx.SHORTPACKETIE field) at DMA Buffer End, i.e. when
UOTGHS_HSTDMASTATUS.BUFF_COUNT reaches 0.
This is mainly for short packet OUT validation initiated by the DMA reaching the end of buffer, but could be used for IN
packet truncation (discarding of unwanted packet data) at the end of DMA buffer.
• END_TR_IT: End of Transfer Interrupt Enable
0: UOTGHS device initiated buffer transfer completion will not trigger any interrupt at
UOTGHS_HSTDMASTATUSx.END_TR_ST rising.
1: an interrupt is sent after the buffer transfer is complete, if the UOTGHS device has ended the buffer transfer.
Use when the receive size is unknown.
• END_BUFFIT: End of Buffer Interrupt Enable
0: UOTGHS_HSTDMASTATUSx.END_BF_ST rising will not trigger any interrupt.
1: an interrupt is generated when UOTGHS_HSTDMASTATUSx.BUFF_COUNT reaches zero.
• DESC_LD_IT: Descriptor Loaded Interrupt Enable
0: UOTGHS_HSTDMASTATUSx.DESC_LDST rising will not trigger any interrupt.
1: an interrupt is generated when a descriptor has been loaded from the bus.
• BURST_LCK: Burst Lock Enable
0: the DMA never locks the bus access.
1: USB packets AHB data bursts are locked for maximum optimization of the bus bandwidth usage and maximization of fly-
by AHB burst duration.
• BUFF_LENGTH: Buffer Byte Length (Write-only)
This field determines the number of bytes to be transferred until end of buffer. The maximum channel transfer size
(32 KBytes) is reached when this field is 0 (default value). If the transfer size is unknown, this field should be set to 0, but
the transfer end may occur earlier under USB device control.
When this field is written, the UOTGHS_HSTDMASTATUSx.BUFF_COUNT field is updated with the write value.
Notes: 1. Bits [31:2] are only writable when issuing a channel Control Command other than “Stop Now”.
2. For reliability it is highly recommended to wait for both UOTGHS_HSTDMASTATUSx.CHAN_ACT and CHAN_ENB flags
are at 0, thus ensuring the channel has been stopped before issuing a command other than “Stop Now”.
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39.6.3.25 Host DMA Channel x Status Register
Name: UOTGHS_HSTDMASTATUSx [x=1..6]
Address: 0x400AC71C [1], 0x400AC72C [2], 0x400AC73C [3], 0x400AC74C [4], 0x400AC75C [5], 0x400AC76C [6],
0x400AC77C [7]
Access: Read-write
• CHANN_ENB: Channel Enable Status
0: if cleared, the DMA channel no longer transfers data, and may load the next descriptor if
UOTGHS_HSTDMACONTROLx.LDNXT_DSC bit is set.
When any transfer is ended either due to an elapsed byte count or a UOTGHS device initiated transfer end, this bit is auto-
matically reset.
1: if set, the DMA channel is currently enabled and transfers data upon request.
This bit is normally set or cleared by writing into UOTGHS_HSTDMACONTROLx.CHANN_ENB bit field either by software
or descriptor loading.
If a channel request is currently serviced when UOTGHS_HSTDMACONTROLx.CHANN_ENB bit is cleared, the DMA
FIFO buffer is drained until it is empty, then this status bit is cleared.
• CHANN_ACT: Channel Active Status
0: the DMA channel is no longer trying to source the packet data.
When a packet transfer is ended this bit is automatically reset.
1: the DMA channel is currently trying to source packet data, i.e. selected as the highest-priority requesting channel.
When a packet transfer cannot be completed due to an END_BF_ST, this flag stays set during the next channel descriptor
load (if any) and potentially until UOTGHS packet transfer completion, if allowed by the new descriptor.
• END_TR_ST: End of Channel Transfer Status
0: cleared automatically when read by software.
1: set by hardware when the last packet transfer is complete, if the UOTGHS device has ended the transfer.
Valid until CHANN_ENB flag is cleared at the end of the next buffer transfer.
• END_BF_ST: End of Channel Buffer Status
0: cleared automatically when read by software.
1: set by hardware when BUFF_COUNT count-down reaches zero.
Valid until CHANN_ENB flag is cleared at the end of the next buffer transfer.
31 30 29 28 27 26 25 24
BUFF_COUNT
23 22 21 20 19 18 17 16
BUFF_COUNT
15 14 13 12 11 10 9 8
––––––––
76543210
– DESC_LDST END_BF_ST END_TR_ST – – CHANN_ACT CHANN_ENB
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• DESC_LDST: Descriptor Loaded Status
0: cleared automatically when read by software.
1: set by hardware when a descriptor has been loaded from the system bus.
Valid until the CHANN_ENB flag is cleared at the end of the next buffer transfer.
• BUFF_COUNT: Buffer Byte Count
This field determines the current number of bytes still to be transferred for this buffer.
This field is decremented from the AHB source bus access byte width at the end of this bus address phase.
The access byte width is 4 by default, or less, at DMA start or end, if the start or end address is not aligned on a word
boundary.
At the end of buffer, the DMA accesses the UOTGHS device only for the number of bytes needed to complete it.
Note: For IN pipes, if the receive buffer byte length (UOTGHS_HSTDMACONTROL.BUFF_LENGTH) has been defaulted to zero
because the USB transfer length is unknown, the actual buffer byte length received will be 0x10000-BUFF_COUNT.
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40. Controller Area Network (CAN)
40.1 Description
The CAN controller provides all the features required to implement the serial communication protocol CAN defined
by Robert Bosch GmbH, the CAN specification as referred to by ISO/11898A (2.0 Part A and 2.0 Part B) for high
speeds and ISO/11519-2 for low speeds. The CAN Controller is able to handle all types of frames (Data, Remote,
Error and Overload) and achieves a bitrate of 1 Mbit/sec.
CAN controller accesses are made through configuration registers. 8 independent message objects (mailboxes)
are implemented.
Any mailbox can be programmed as a reception buffer block (even non-consecutive buffers). For the reception of
defined messages, one or several message objects can be masked without participating in the buffer feature. An
interrupt is generated when the buffer is full. According to the mailbox configuration, the first message received
can be locked in the CAN controller registers until the application acknowledges it, or this message can be
discarded by new received messages.
Any mailbox can be programmed for transmission. Several transmission mailboxes can be enabled in the same
time. A priority can be defined for each mailbox independently.
An internal 16-bit timer is used to stamp each received and sent message. This timer starts counting as soon as
the CAN controller is enabled. This counter can be reset by the application or automatically after a reception in the
last mailbox in Time Triggered Mode.
The CAN controller offers optimized features to support the Time Triggered Communication (TTC) protocol.
40.2 Embedded Characteristics
Fully Compliant with CAN 2.0 Part A and 2.0 Part B
Bit Rates up to 1Mbit/s
8 Object Oriented Mailboxes with the Following Properties:
̶CAN Specification 2.0 Part A or 2.0 Part B Programmable for Each Message
̶Object Configurable in Receive (with Overwrite or Not) or Transmit Modes
̶Independent 29-bit Identifier and Mask Defined for Each Mailbox
̶32-bit Access to Data Registers for Each Mailbox Data Object
̶Uses a 16-bit Timestamp on Receive and Transmit Messages
̶Hardware Concatenation of ID Masked Bitfields To Speed Up Family ID Processing
16-bit Internal Timer for Timestamping and Network Synchronization
Programmable Reception Buffer Length up to 8 Mailbox Objects
Priority Management between Transmission Mailboxes
Autobaud and Listening Mode
Low Power Mode and Programmable Wake-up on Bus Activity or by the Application
Data, Remote, Error and Overload Frame Handling
Write Protected Registers
&& User Interface 1 4—*—> RX AtmeL
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40.3 Block Diagram
Figure 40-1. CAN Block Diagram
40.4 Application Block Diagram
Figure 40-2.
Application Block Diagram
Internal Bus
CAN Interrupt
CANRX
Controller Area Network
PIO
CANTX
Error Counter
User Interface
PMC
MCK
Mailbox
Priority
Encoder
MB0
MBx
(x = number of mailboxes - 1)
Control
&
Status
CAN Protocol Controller
MB1
Software
Software
CAN Controller
Transceiver
Implementatio
n
Layers
CAN-based Application Layer
CAN-based Profiles
CAN Data Link Layer
CAN Physical Layer
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40.5 I/O Lines Description
40.6 Product Dependencies
40.6.1 I/O Lines
The pins used for interfacing the CAN may be multiplexed with the PIO lines. The programmer must first program
the PIO controller to assign the desired CAN pins to their peripheral function. If I/O lines of the CAN are not used
by the application, they can be used for other purposes by the PIO Controller.
40.6.2 Power Management
The programmer must first enable the CAN clock in the Power Management Controller (PMC) before using the
CAN.
A Low-power Mode is defined for the CAN controller. If the application does not require CAN operations, the CAN
clock can be stopped when not needed and be restarted later. Before stopping the clock, the CAN Controller must
be in Low-power Mode to complete the current transfer. After restarting the clock, the application must disable the
Low-power Mode of the CAN controller.
40.6.3 Interrupt
The CAN interrupt line is connected on one of the internal sources of the Advanced Interrupt Controller. Using the
CAN interrupt requires the AIC to be programmed first. Note that it is not recommended to use the CAN interrupt
line in edge-sensitive mode.
Table 40-1. I/O Lines Description
Name Description Type
CANRX CAN Receive Serial Data Input
CANTX CAN Transmit Serial Data Output
Table 40-2. I/O Lines
Instance Signal I/O Line Peripheral
CAN0 CANRX0 PA1 A
CAN0 CANTX0 PA0 A
CAN1 CANRX1 PB15 A
CAN1 CANTX1 PB14 A
Table 40-3. Peripheral IDs
Instance ID
CAN0 43
CAN1 44
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40.7 CAN Controller Features
40.7.1 CAN Protocol Overview
The Controller Area Network (CAN) is a multi-master serial communication protocol that efficiently supports real-
time control with a very high level of security with bit rates up to 1 Mbit/s.
The CAN protocol supports four different frame types:
Data frames: They carry data from a transmitter node to the receiver nodes. The overall maximum data
frame length is 108 bits for a standard frame and 128 bits for an extended frame.
Remote frames: A destination node can request data from the source by sending a remote frame with an
identifier that matches the identifier of the required data frame. The appropriate data source node then
sends a data frame as a response to this node request.
Error frames: An error frame is generated by any node that detects a bus error.
Overload frames: They provide an extra delay between the preceding and the successive data frames or
remote frames.
The Atmel CAN controller provides the CPU with full functionality of the CAN protocol V2.0 Part A and V2.0 Part B.
It minimizes the CPU load in communication overhead. The Data Link Layer and part of the physical layer are
automatically handled by the CAN controller itself.
The CPU reads or writes data or messages via the CAN controller mailboxes. An identifier is assigned to each
mailbox. The CAN controller encapsulates or decodes data messages to build or to decode bus data frames.
Remote frames, error frames and overload frames are automatically handled by the CAN controller under
supervision of the software application.
40.7.2 Mailbox Organization
The CAN module has 8 buffers, also called channels or mailboxes. An identifier that corresponds to the CAN
identifier is defined for each active mailbox. Message identifiers can match the standard frame identifier or the
extended frame identifier. This identifier is defined for the first time during the CAN initialization, but can be
dynamically reconfigured later so that the mailbox can handle a new message family. Several mailboxes can be
configured with the same ID.
Each mailbox can be configured in receive or in transmit mode independently. The mailbox object type is defined
in the MOT field of the CAN_MMRx register.
40.7.2.1 Message Acceptance Procedure
If the MIDE field in the CAN_MIDx register is set, the mailbox can handle the extended format identifier; otherwise,
the mailbox handles the standard format identifier. Once a new message is received, its ID is masked with the
CAN_MAMx value and compared with the CAN_MIDx value. If accepted, the message ID is copied to the
CAN_MIDx register.
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Figure 40-3. Message Acceptance Procedure
If a mailbox is dedicated to receiving several messages (a family of messages) with different IDs, the acceptance
mask defined in the CAN_MAMx register must mask the variable part of the ID family. Once a message is
received, the application must decode the masked bits in the CAN_MIDx. To speed up the decoding, masked bits
are grouped in the family ID register (CAN_MFIDx).
For example, if the following message IDs are handled by the same mailbox:
ID0 101000100100010010000100 0 11 00b
ID1 101000100100010010000100 0 11 01b
ID2 101000100100010010000100 0 11 10b
ID3 101000100100010010000100 0 11 11b
ID4 101000100100010010000100 1 11 00b
ID5 101000100100010010000100 1 11 01b
ID6 101000100100010010000100 1 11 10b
ID7 101000100100010010000100 1 11 11b
The CAN_MIDx and CAN_MAMx of Mailbox x must be initialized to the corresponding values:
CAN_MIDx = 001 101000100100010010000100 x 11 xxb
CAN_MAMx = 001 111111111111111111111111 0 11 00b
If Mailbox x receives a message with ID6, then CAN_MIDx and CAN_MFIDx are set:
CAN_MIDx = 001 101000100100010010000100 1 11 10b
CAN_MFIDx = 00000000000000000000000000000110b
If the application associates a handler for each message ID, it may define an array of pointers to functions:
void (*pHandler[8])(void);
When a message is received, the corresponding handler can be invoked using CAN_MFIDx register and there is
no need to check masked bits:
unsigned int MFID0_register;
MFID0_register = Get_CAN_MFID0_Register();
// Get_CAN_MFID0_Register() returns the value of the CAN_MFID0 register
pHandler[MFID0_register]();
CAN_MIDx CAN_MAMx Message Received
& &
==
Message Accepted
Message Refused
No
Yes
CAN_MFIDx
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40.7.2.2 Receive Mailbox
When the CAN module receives a message, it looks for the first available mailbox with the lowest number and
compares the received message ID with the mailbox ID. If such a mailbox is found, then the message is stored in
its data registers. Depending on the configuration, the mailbox is disabled as long as the message has not been
acknowledged by the application (Receive only), or, if new messages with the same ID are received, then they
overwrite the previous ones (Receive with overwrite).
It is also possible to configure a mailbox in Consumer Mode. In this mode, after each transfer request, a remote
frame is automatically sent. The first answer received is stored in the corresponding mailbox data registers.
Several mailboxes can be chained to receive a buffer. They must be configured with the same ID in Receive Mode,
except for the last one, which can be configured in Receive with Overwrite Mode. The last mailbox can be used to
detect a buffer overflow.
40.7.2.3 Transmit Mailbox
When transmitting a message, the message length and data are written to the transmit mailbox with the correct
identifier. For each transmit mailbox, a priority is assigned. The controller automatically sends the message with
the highest priority first (set with the field PRIOR in CAN_MMRx register).
It is also possible to configure a mailbox in Producer Mode. In this mode, when a remote frame is received, the
mailbox data are sent automatically. By enabling this mode, a producer can be done using only one mailbox
instead of two: one to detect the remote frame and one to send the answer.
Table 40-4.
Mailbox Object Type Description
Receive The first message received is stored in mailbox data registers. Data remain available until the
next transfer request.
Receive with overwrite The last message received is stored in mailbox data register. The next message always
overwrites the previous one. The application has to check whether a new message has not
overwritten the current one while reading the data registers.
Consumer A remote frame is sent by the mailbox. The answer received is stored in mailbox data register.
This extends Receive mailbox features. Data remain available until the next transfer request.
Table 40-5.
Mailbox Object Type Description
Transmit
The message stored in the mailbox data registers will try to win the bus arbitration immediately
or later according to or not the Time Management Unit configuration (see Section 40.7.3).
The application is notified that the message has been sent or aborted.
Producer The message prepared in the mailbox data registers will be sent after receiving the next remote
frame. This extends transmit mailbox features.
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40.7.3 Time Management Unit
The CAN Controller integrates a free-running 16-bit internal timer. The counter is driven by the bit clock of the CAN
bus line. It is enabled when the CAN controller is enabled (CANEN set in the CAN_MR register). It is automatically
cleared in the following cases:
after a reset
when the CAN controller is in Low-power Mode is enabled (LPM bit set in the CAN_MR and SLEEP bit set in
the CAN_SR)
after a reset of the CAN controller (CANEN bit in the CAN_MR register)
in Time-triggered Mode, when a message is accepted by the last mailbox (rising edge of the MRDY signal in
the CAN_MSRlast_mailbox_number register).
The application can also reset the internal timer by setting TIMRST in the CAN_TCR register. The current value of
the internal timer is always accessible by reading the CAN_TIM register.
When the timer rolls-over from FFFFh to 0000h, TOVF (Timer Overflow) signal in the CAN_SR register is set.
TOVF bit in the CAN_SR register is cleared by reading the CAN_SR register. Depending on the corresponding
interrupt mask in the CAN_IMR register, an interrupt is generated while TOVF is set.
In a CAN network, some CAN devices may have a larger counter. In this case, the application can also decide to
freeze the internal counter when the timer reaches FFFFh and to wait for a restart condition from another device.
This feature is enabled by setting TIMFRZ in the CAN_MR register. The CAN_TIM register is frozen to the FFFFh
value. A clear condition described above restarts the timer. A timer overflow (TOVF) interrupt is triggered.
To monitor the CAN bus activity, the CAN_TIM register is copied to the CAN _TIMESTP register after each start of
frame or end of frame and a TSTP interrupt is triggered. If TEOF bit in the CAN_MR register is set, the value is
captured at each End Of Frame, else it is captured at each Start Of Frame. Depending on the corresponding mask
in the CAN_IMR register, an interrupt is generated while TSTP is set in the CAN_SR. TSTP bit is cleared by
reading the CAN_SR register.
The time management unit can operate in one of the two following modes:
Timestamping mode: The value of the internal timer is captured at each Start Of Frame or each End Of
Frame
Time Triggered mode: A mailbox transfer operation is triggered when the internal timer reaches the mailbox
trigger.
Timestamping Mode is enabled by clearing TTM field in the CAN_MR register. Time Triggered Mode is enabled by
setting TTM field in the CAN_MR register.
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40.7.4 CAN 2.0 Standard Features
40.7.4.1 CAN Bit Timing Configuration
All controllers on a CAN bus must have the same bit rate and bit length. At different clock frequencies of the
individual controllers, the bit rate has to be adjusted by the time segments.
The CAN protocol specification partitions the nominal bit time into four different segments:
Figure 40-4. Partition of the CAN Bit Time
TIME QUANTUM
The TIME QUANTUM (TQ) is a fixed unit of time derived from the MCK period. The total number of TIME
QUANTA in a bit time is programmable from 8 to 25.
SYNC SEG: SYNChronization Segment.
This part of the bit time is used to synchronize the various nodes on the bus. An edge is expected to lie within this
segment. It is 1 TQ long.
PROP SEG: PROPagation Segment.
This part of the bit time is used to compensate for the physical delay times within the network. It is twice the sum of
the signal’s propagation time on the bus line, the input comparator delay, and the output driver delay. It is
programmable to be 1,2,..., 8 TQ long.
This parameter is defined in the PROPAG field of the ”CAN Baudrate Register”.
PHASE SEG1, PHASE SEG2: PHASE Segment 1 and 2.
The Phase-Buffer-Segments are used to compensate for edge phase errors. These segments can be lengthened
(PHASE SEG1) or shortened (PHASE SEG2) by resynchronization.
Phase Segment 1 is programmable to be 1,2,..., 8 TQ long.
Phase Segment 2 length has to be at least as long as the Information Processing Time (IPT) and may not be more
than the length of Phase Segment 1.
These parameters are defined in the PHASE1 and PHASE2 fields of the ”CAN Baudrate Register”.
INFORMATION PROCESSING TIME:
The Information Processing Time (IPT) is the time required for the logic to determine the bit level of a sampled bit.
The IPT begins at the sample point, is measured in TQ and is fixed at 2 TQ for the Atmel CAN. Since Phase
Segment 2 also begins at the sample point and is the last segment in the bit time, PHASE SEG2 shall not be less
than the IPT.
SAMPLE POINT:
The SAMPLE POINT is the point in time at which the bus level is read and interpreted as the value of that
respective bit. Its location is at the end of PHASE_SEG1.
SJW: ReSynchronization Jump Width.
The ReSynchronization Jump Width defines the limit to the amount of lengthening or shortening of the Phase
Segments.
SYNC_SEG PROP_SEG PHASE_SEG1 PHASE_SEG2
NOMINAL BIT TIME
Sample Point
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SJW is programmable to be the minimum of PHASE SEG1 and 4 TQ.
If the SMP field in the CAN_BR register is set, then the incoming bit stream is sampled three times with a period of
half a CAN clock period, centered on sample point.
In the CAN controller, the length of a bit on the CAN bus is determined by the parameters (BRP, PROPAG,
PHASE1 and PHASE2).
The time quantum is calculated as follows:
Note: The BRP field must be within the range [1, 0x7F], i.e., BRP = 0 is not authorized.
To compensate for phase shifts between clock oscillators of different controllers on the bus, the CAN controller
must resynchronize on any relevant signal edge of the current transmission. The resynchronization shortens or
lengthens the bit time so that the position of the sample point is shifted with regard to the detected edge. The
resynchronization jump width (SJW) defines the maximum of time by which a bit period may be shortened or
lengthened by resynchronization.
Figure 40-5. CAN Bit Timing
tBIT tCSC tPRS tPHS1 tPHS2
++ +=
tCSC BRP 1+()MCK⁄=
tPRS tCSC PROPAG 1+()×=
tPHS1 tCSC PHASE1 1+()×=
tPHS2 tCSC PHASE2 1+()×=
tSJW tCSC SJW 1+()×=
SYNC_
SEG PROP_SEG PHASE_SEG1 PHASE_SEG2
NOMINAL BIT TIME
Sample Point Transmission Point
MCK
CAN Clock
t
CSC
t
PRS
t
PHS1
t
PHS2
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Example of bit timing determination for CAN baudrate of 500 Kbit/s:
MCK = 48MHz
CAN baudrate= 500kbit/s => bit time= 2us
Delay of the bus driver: 50 ns
Delay of the receiver: 30ns
Delay of the bus line (20m): 110ns
The total number of time quanta in a bit time must be comprised between 8 and
25. If we fix the bit time to 16 time quanta:
Tcsc = 1 time quanta = bit time / 16 = 125 ns
=> BRP = (Tcsc x MCK) - 1 = 5
The propagation segment time is equal to twice the sum of the signal’s
propagation time on the bus line, the receiver delay and the output driver
delay:
Tprs = 2 * (50+30+110) ns = 380 ns = 3 Tcsc
=> PROPAG = Tprs/Tcsc - 1 = 2
The remaining time for the two phase segments is:
Tphs1 + Tphs2 = bit time - Tcsc - Tprs = (16 - 1 - 3)Tcsc
Tphs1 + Tphs2 = 12 Tcsc
Because this number is even, we choose Tphs2 = Tphs1 (else we would choose Tphs2
= Tphs1 + Tcsc)
Tphs1 = Tphs2 = (12/2) Tcsc = 6 Tcsc
=> PHASE1 = PHASE2 = Tphs1/Tcsc - 1 = 5
The resynchronization jump width must be comprised between 1 Tcsc and the
minimum of 4 Tcsc and Tphs1. We choose its maximum value:
Tsjw = Min(4 Tcsc,Tphs1) = 4 Tcsc
=> SJW = Tsjw/Tcsc - 1 = 3
Finally: CAN_BR = 0x00053255
CAN Bus Synchronization
Two types of synchronization are distinguished: “hard synchronization” at the start of a frame and
“resynchronization” inside a frame. After a hard synchronization, the bit time is restarted with the end of the
SYNC_SEG segment, regardless of the phase error. Resynchronization causes a reduction or increase in the bit
time so that the position of the sample point is shifted with respect to the detected edge.
The effect of resynchronization is the same as that of hard synchronization when the magnitude of the phase error
of the edge causing the resynchronization is less than or equal to the programmed value of the resynchronization
jump width (tSJW).
When the magnitude of the phase error is larger than the resynchronization jump width and
the phase error is positive, then PHASE_SEG1 is lengthened by an amount equal to the resynchronization
jump width.
the phase error is negative, then PHASE_SEG2 is shortened by an amount equal to the resynchronization
jump width.
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Figure 40-6. CAN Resynchronization
Autobaud Mode
The autobaud feature is enabled by setting the ABM field in the CAN_MR register. In this mode, the CAN controller
is only listening to the line without acknowledging the received messages. It can not send any message. The
errors flags are updated. The bit timing can be adjusted until no error occurs (good configuration found). In this
mode, the error counters are frozen. To go back to the standard mode, the ABM bit must be cleared in the
CAN_MR register.
40.7.4.2 Error Detection
There are five different error types that are not mutually exclusive. Each error concerns only specific fields of the
CAN data frame (refer to the Bosch CAN specification for their correspondence):
CRC error (CERR bit in the CAN_SR register): With the CRC, the transmitter calculates a checksum for the
CRC bit sequence from the Start of Frame bit until the end of the Data Field. This CRC sequence is
transmitted in the CRC field of the Data or Remote Frame.
Bit-stuffing error (SERR bit in the CAN_SR register): If a node detects a sixth consecutive equal bit level
during the bit-stuffing area of a frame, it generates an Error Frame starting with the next bit-time.
Bit error (BERR bit in CAN_SR register): A bit error occurs if a transmitter sends a dominant bit but detects a
recessive bit on the bus line, or if it sends a recessive bit but detects a dominant bit on the bus line. An error
frame is generated and starts with the next bit time.
Form Error (FERR bit in the CAN_SR register): If a transmitter detects a dominant bit in one of the fix-
formatted segments CRC Delimiter, ACK Delimiter or End of Frame, a form error has occurred and an error
frame is generated.
Acknowledgment error (AERR bit in the CAN_SR register): The transmitter checks the Acknowledge Slot,
which is transmitted by the transmitting node as a recessive bit, contains a dominant bit. If this is the case, at
least one other node has received the frame correctly. If not, an Acknowledge Error has occurred and the
transmitter will start in the next bit-time an Error Frame transmission.
SYNC_
SEG PROP_SEG PHASE_SEG1 PHASE_SEG2
SYNC_
SEG PROP_SEG PHASE_SEG1 PHASE_SEG2
Phase error Phase error (max Tsjw)
SYNC_
SEG
SYNC_
SEG
SYNC_
SEG PROP_SEG PHASE_SEG1
PHASE_SEG2 SYNC_
SEG
PHASE_SEG2
SYNC_
SEG PROP_SEG PHASE_SEG1
PHASE_
SEG2 SYNC_
SEG
PHASE_SEG2
Phase error
Nominal
Sample point Sample point
after resynchronization
Nominal
Sample point
Sample point
after resynchronization
THE PHASE ERROR IS POSITIVE
(the transmitter is slower than the receiver)
Received
data bit
Received
data bit
Nominal bit time
(before resynchronization)
Bit time with
resynchronization
Bit time with
resynchronization
Phase error (max Tsjw)
Nominal bit time
(before resynchronization)
THE PHASE ERROR IS NEGATIVE
(the transmitter is faster than the receiver)
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Fault Confinement
To distinguish between temporary and permanent failures, every CAN controller has two error counters: REC
(Receive Error Counter) and TEC (Transmit Error Counter). The two counters are incremented upon detected
errors and are decremented upon correct transmissions or receptions, respectively. Depending on the counter
values, the state of the node changes: the initial state of the CAN controller is Error Active, meaning that the
controller can send Error Active flags. The controller changes to the Error Passive state if there is an accumulation
of errors. If the CAN controller fails or if there is an extreme accumulation of errors, there is a state transition to Bus
Off.
Figure 40-7. Line Error Mode
An error active unit takes part in bus communication and sends an active error frame when the CAN controller
detects an error.
An error passive unit cannot send an active error frame. It takes part in bus communication, but when an error is
detected, a passive error frame is sent. Also, after a transmission, an error passive unit waits before initiating
further transmission.
A bus off unit is not allowed to have any influence on the bus.
For fault confinement, two errors counters (TEC and REC) are implemented. These counters are accessible via
the CAN_ECR register. The state of the CAN controller is automatically updated according to these counter
values. If the CAN controller is in Error Active state, then the ERRA bit is set in the CAN_SR register. The
corresponding interrupt is pending while the interrupt is not masked in the CAN_IMR register. If the CAN controller
is in Error Passive Mode, then the ERRP bit is set in the CAN_SR register and an interrupt remains pending while
the ERRP bit is set in the CAN_IMR register. If the CAN is in Bus Off Mode, then the BOFF bit is set in the
CAN_SR register. As for ERRP and ERRA, an interrupt is pending while the BOFF bit is set in the CAN_IMR
register.
When one of the error counters values exceeds 96, an increased error rate is indicated to the controller through
the WARN bit in CAN_SR register, but the node remains error active. The corresponding interrupt is pending while
the interrupt is set in the CAN_IMR register.
Refer to the Bosch CAN specification v2.0 for details on fault confinement.
Error Interrupt Handler
WARN, BOFF, ERRA and ERRP (CAN_SR) represent the current status of the CAN bus and are not latched.
They reflect the current TEC and REC (CAN_ECR) values as described in Section “Fault Confinement” on page
1196.
Based on that, if these bits are used as an interrupt, the user can enter into an interrupt and not see the
corresponding status register if the TEC and REC counter have changed their state. When entering Bus Off Mode,
the only way to exit from this state is 128 occurrences of 11 consecutive recessive bits or a CAN controller reset.
ERROR
ACTIVE
ERROR
PASSIVE BUS OFF
TEC > 255
Init
TEC > 127
or
REC > 127
TEC < 127
and
REC < 127
128 occurences of 11 consecutive recessive bits
or
CAN controller reset
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In Error Active Mode, the user reads:
ERRA =1
ERRP = 0
BOFF = 0
In Error Passive Mode, the user reads:
ERRA = 0
ERRP =1
BOFF = 0
In Bus Off Mode, the user reads:
ERRA = 0
ERRP =1
BOFF =1
The CAN interrupt handler should do the following:
Only enable one error mode interrupt at a time.
Look at and check the REC and TEC values in the interrupt handler to determine the current state.
40.7.4.3 Overload
The overload frame is provided to request a delay of the next data or remote frame by the receiver node (“Request
overload frame”) or to signal certain error conditions (“Reactive overload frame”) related to the intermission field
respectively.
Reactive overload frames are transmitted after detection of the following error conditions:
Detection of a dominant bit during the first two bits of the intermission field
Detection of a dominant bit in the last bit of EOF by a receiver, or detection of a dominant bit by a receiver or
a transmitter at the last bit of an error or overload frame delimiter
The CAN controller can generate a request overload frame automatically after each message sent to one of the
CAN controller mailboxes. This feature is enabled by setting the OVL bit in the CAN_MR register.
Reactive overload frames are automatically handled by the CAN controller even if the OVL bit in the CAN_MR
register is not set. An overload flag is generated in the same way as an error flag, but error counters do not
increment.
40.7.5 Low-power Mode
In Low-power Mode, the CAN controller cannot send or receive messages. All mailboxes are inactive.
In Low-power Mode, the SLEEP signal in the CAN_SR register is set; otherwise, the WAKEUP signal in the
CAN_SR register is set. These two fields are exclusive except after a CAN controller reset (WAKEUP and SLEEP
are stuck at 0 after a reset). After power-up reset, the Low-power Mode is disabled and the WAKEUP bit is set in
the CAN_SR register only after detection of 11 consecutive recessive bits on the bus.
40.7.5.1 Enabling Low-power Mode
A software application can enable Low-power Mode by setting the LPM bit in the CAN_MR global register. The
CAN controller enters Low-power Mode once all pending transmit messages are sent.
When the CAN controller enters Low-power Mode, the SLEEP signal in the CAN_SR register is set. Depending on
the corresponding mask in the CAN_IMR register, an interrupt is generated while SLEEP is set.
The SLEEP signal in the CAN_SR register is automatically cleared once WAKEUP is set. The WAKEUP signal is
automatically cleared once SLEEP is set.
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Reception is disabled while the SLEEP signal is set to one in the CAN_SR register. It is important to note that
those messages with higher priority than the last message transmitted can be received between the LPM
command and entry in Low-power Mode.
Once in Low-power Mode, the CAN controller clock can be switched off by programming the chip’s Power
Management Controller (PMC). The CAN controller drains only the static current.
Error counters are disabled while the SLEEP signal is set to one.
Thus, to enter Low-power Mode, the software application must:
̶Set LPM field in the CAN_MR register
̶Wait for SLEEP signal rising
Now the CAN Controller clock can be disabled. This is done by programming the Power Management Controller
(PMC).
Figure 40-8. Enabling Low-power Mode
40.7.5.2 Disabling Low-power Mode
The CAN controller can be awake after detecting a CAN bus activity. Bus activity detection is done by an external
module that may be embedded in the chip. When it is notified of a CAN bus activity, the software application
disables Low-power Mode by programming the CAN controller.
To disable Low-power Mode, the software application must:
̶Enable the CAN Controller clock. This is done by programming the Power Management Controller
(PMC).
̶Clear the LPM field in the CAN_MR register
The CAN controller synchronizes itself with the bus activity by checking for eleven consecutive “recessive” bits.
Once synchronized, the WAKEUP signal in the CAN_SR register is set.
Depending on the corresponding mask in the CAN_IMR register, an interrupt is generated while WAKEUP is set.
The SLEEP signal in the CAN_SR register is automatically cleared once WAKEUP is set. WAKEUP signal is
automatically cleared once SLEEP is set.
If no message is being sent on the bus, then the CAN controller is able to send a message eleven bit times after
disabling Low-power Mode.
SLEEP
(CAN_SR)
MRDY
(CAN_MSR1)
LPM
(CAN_MR)
LPEN= 1
CAN BUS
MRDY
(CAN_MSR3)
Mailbox 1 Mailbox 3
Arbitration lost
WAKEUP
(CAN_SR)
0x0CAN_TIM
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If there is bus activity when Low-power mode is disabled, the CAN controller is synchronized with the bus activity
in the next interframe. The previous message is lost (see Figure 40-9).
Figure 40-9. Disabling Low-power Mode
40.8 Functional Description
40.8.1 CAN Controller Initialization
After power-up reset, the CAN controller is disabled. The CAN controller clock must be activated by the Power
Management Controller (PMC) and the CAN controller interrupt line must be enabled by the interrupt controller
(AIC).
The CAN controller must be initialized with the CAN network parameters. The CAN_BR register defines the
sampling point in the bit time period. CAN_BR must be set before the CAN controller is enabled by setting the
CANEN field in the CAN_MR register.
The CAN controller is enabled by setting the CANEN flag in the CAN_MR register. At this stage, the internal CAN
controller state machine is reset, error counters are reset to 0, error flags are reset to 0.
Once the CAN controller is enabled, bus synchronization is done automatically by scanning eleven recessive bits.
The WAKEUP bit in the CAN_SR register is automatically set to 1 when the CAN controller is synchronized
(WAKEUP and SLEEP are stuck at 0 after a reset).
The CAN controller can start listening to the network in Autobaud Mode. In this case, the error counters are locked
and a mailbox may be configured in Receive Mode. By scanning error flags, the CAN_BR register values
synchronized with the network. Once no error has been detected, the application disables the Autobaud Mode,
clearing the ABM field in the CAN_MR register.
SLEEP
(CAN_SR)
MRDY
(CAN_MSRx)
LPM
(CAN_MR)
CAN BUS
Bus Activity Detected
Message x
Interframe synchronization
WAKEUP
(CAN_SR)
Message lost
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Figure 40-10. Possible Initialization Procedure
40.8.2 CAN Controller Interrupt Handling
There are two different types of interrupts. One type of interrupt is a message-object related interrupt, the other is
a system interrupt that handles errors or system-related interrupt sources.
All interrupt sources can be masked by writing the corresponding field in the CAN_IDR register. They can be
unmasked by writing to the CAN_IER register. After a power-up reset, all interrupt sources are disabled (masked).
The current mask status can be checked by reading the CAN_IMR register.
The CAN_SR register gives all interrupt source states.
The following events may initiate one of the two interrupts:
Message object interrupt
̶Data registers in the mailbox object are available to the application. In Receive Mode, a new message
was received. In Transmit Mode, a message was transmitted successfully.
̶A sent transmission was aborted.
System interrupts
̶Bus off interrupt: The CAN module enters the bus off state.
̶Error passive interrupt: The CAN module enters Error Passive Mode.
̶Error Active Mode: The CAN module is neither in Error Passive Mode nor in Bus Off mode.
̶Warn Limit interrupt: The CAN module is in Error-active Mode, but at least one of its error counter
value exceeds 96.
̶Wake-up interrupt: This interrupt is generated after a wake-up and a bus synchronization.
̶Sleep interrupt: This interrupt is generated after a Low-power Mode enable once all pending
messages in transmission have been sent.
Errors ?
No
Yes
(ABM == 1 and CANEN == 1)
CANEN = 1 (ABM == 0)
ABM = 0 and CANEN = 0
(CAN_SR or CAN_MSRx)
Change CAN_BR value
End of Initialization
Configure a Mailbox in Reception Mode
Enable CAN Controller Interrupt Line
Enable CAN Controller Clock
(AIC)
(PMC)
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̶Internal timer counter overflow interrupt: This interrupt is generated when the internal timer rolls over.
̶Timestamp interrupt: This interrupt is generated after the reception or the transmission of a start of
frame or an end of frame. The value of the internal counter is copied in the CAN_TIMESTP register.
All interrupts are cleared by clearing the interrupt source except for the internal timer counter overflow interrupt and
the timestamp interrupt. These interrupts are cleared by reading the CAN_SR register.
40.8.3 CAN Controller Message Handling
40.8.3.1 Receive Handling
Two modes are available to configure a mailbox to receive messages. In Receive Mode, the first message
received is stored in the mailbox data register. In Receive with Overwrite Mode, the last message received is
stored in the mailbox.
Simple Receive Mailbox
A mailbox is in Receive Mode once the MOT field in the CAN_MMRx register has been configured. Message ID
and Message Acceptance Mask must be set before the Receive Mode is enabled.
After Receive Mode is enabled, the MRDY flag in the CAN_MSR register is automatically cleared until the first
message is received. When the first message has been accepted by the mailbox, the MRDY flag is set. An
interrupt is pending for the mailbox while the MRDY flag is set. This interrupt can be masked depending on the
mailbox flag in the CAN_IMR global register.
Message data are stored in the mailbox data register until the software application notifies that data processing
has ended. This is done by asking for a new transfer command, setting the MTCR flag in the CAN_MCRx register.
This automatically clears the MRDY signal.
The MMI flag in the CAN_MSRx register notifies the software that a message has been lost by the mailbox. This
flag is set when messages are received while MRDY is set in the CAN_MSRx register. This flag is cleared by
reading the CAN_MSRs register. A receive mailbox prevents from overwriting the first message by new ones while
MRDY flag is set in the CAN_MSRx register. See Figure 40-11.
Figure 40-11. Receive Mailbox
Note: In the case of ARM architecture, CAN_MSRx, CAN_MDLx, CAN_MDHx can be read using an optimized ldm assembler
instruction.
Message 1 Message 2 lostMessage 3
Message 3
Message 1
Reading CAN_MSRx
Reading CAN_MDHx & CAN_MDLx
Writing CAN_MCRx
MMI
(CAN_MSRx)
MRDY
(CAN_MSRx)
CAN BUS
(CAN_MDLx
CAN_MDHx)
MTCR
(CAN_MCRx)
Message ID = CAN_MIDx
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Receive with Overwrite Mailbox
A mailbox is in Receive with Overwrite Mode once the MOT field in the CAN_MMRx register has been configured.
Message ID and Message Acceptance masks must be set before Receive Mode is enabled.
After Receive Mode is enabled, the MRDY flag in the CAN_MSR register is automatically cleared until the first
message is received. When the first message has been accepted by the mailbox, the MRDY flag is set. An
interrupt is pending for the mailbox while the MRDY flag is set. This interrupt is masked depending on the mailbox
flag in the CAN_IMR global register.
If a new message is received while the MRDY flag is set, this new message is stored in the mailbox data register,
overwriting the previous message. The MMI flag in the CAN_MSRx register notifies the software that a message
has been dropped by the mailbox. This flag is cleared when reading the CAN_MSRx register.
The CAN controller may store a new message in the CAN data registers while the application reads them. To
check that CAN_MDHx and CAN_MDLx do not belong to different messages, the application must check the MMI
field in the CAN_MSRx register before and after reading CAN_MDHx and CAN_MDLx. If the MMI flag is set again
after the data registers have been read, the software application has to re-read CAN_MDHx and CAN_MDLx (see
Figure 40-12).
Figure 40-12. Receive with Overwrite Mailbox
Chaining Mailboxes
Several mailboxes may be used to receive a buffer split into several messages with the same ID. In this case, the
mailbox with the lowest number is serviced first. In the receive and receive with overwrite modes, the field PRIOR
in the CAN_MMRx register has no effect. If Mailbox 0 and Mailbox 5 accept messages with the same ID, the first
message is received by Mailbox 0 and the second message is received by Mailbox 5. Mailbox 0 must be
configured in Receive Mode (i.e., the first message received is considered) and Mailbox 5 must be configured in
Receive with Overwrite Mode. Mailbox 0 cannot be configured in Receive with Overwrite Mode; otherwise, all
messages are accepted by this mailbox and Mailbox 5 is never serviced.
If several mailboxes are chained to receive a buffer split into several messages, all mailboxes except the last one
(with the highest number) must be configured in Receive Mode. The first message received is handled by the first
mailbox, the second one is refused by the first mailbox and accepted by the second mailbox, the last message is
accepted by the last mailbox and refused by previous ones (see Figure 40-13).
Message 1 Message 2 Message 3
Message 3 Message 1
Reading CAN_MSRx
Reading CAN_MDHx & CAN_MDLx
Writing CAN_MCRx
MMI
(CAN_MSRx)
MRDY
(CAN_MSRx)
CAN BUS
(CAN_MDLx
CAN_MDHx)
MTCR
(CAN_MCRx)
Message ID = CAN_MIDx
Message 4
Message 2 Message 4
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Figure 40-13. Chaining Three Mailboxes to Receive a Buffer Split into Three Messages
If the number of mailboxes is not sufficient (the MMI flag of the last mailbox raises), the user must read each data
received on the last mailbox in order to retrieve all the messages of the buffer split (see Figure 40-14).
Figure 40-14. Chaining Three Mailboxes to Receive a Buffer Split into Four Messages
MMI
(CAN_MSRx)
MRDY
(CAN_MSRx)
CAN BUSMessage s1
Reading CAN_MSRx, CAN_MSRy and CAN_MSRz
Writing MBx MBy MBz in CAN_TCR
Reading CAN_MDH & CAN_MDL for mailboxes x, y and z
MMI
(CAN_MSRy)
MRDY
(CAN_MSRy)
MMI
(CAN_MSRz)
MRDY
(CAN_MSRz)
Message s2Message s3
Buffer split in 3 messages
MMI
(CAN_MSRx)
MRDY
(CAN_MSRx)
CAN BUSMessage s1
Reading CAN_MSRx, CAN_MSRy and CAN_MSRz
Writing MBx MBy MBz in CAN_TCR
Reading CAN_MDH & CAN_MDL for mailboxes x, y and z
MMI
(CAN_MSRy)
MRDY
(CAN_MSRy)
MMI
(CAN_MSRz)
MRDY
(CAN_MSRz)
Message s2Message s3
Buffer split in 4 messages
Message s4
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1204
40.8.3.2 Transmission Handling
A mailbox is in Transmit Mode once the MOT field in the CAN_MMRx register has been configured. Message ID
and Message Acceptance mask must be set before Receive Mode is enabled.
After Transmit Mode is enabled, the MRDY flag in the CAN_MSR register is automatically set until the first
command is sent. When the MRDY flag is set, the software application can prepare a message to be sent by
writing to the CAN_MDx registers. The message is sent once the software asks for a transfer command setting the
MTCR bit and the message data length in the CAN_MCRx register.
The MRDY flag remains at zero as long as the message has not been sent or aborted. It is important to note that
no access to the mailbox data register is allowed while the MRDY flag is cleared. An interrupt is pending for the
mailbox while the MRDY flag is set. This interrupt can be masked depending on the mailbox flag in the CAN_IMR
global register.
It is also possible to send a remote frame setting the MRTR bit instead of setting the MDLC field. The answer to
the remote frame is handled by another reception mailbox. In this case, the device acts as a consumer but with the
help of two mailboxes. It is possible to handle the remote frame emission and the answer reception using only one
mailbox configured in Consumer Mode. Refer to the section “Remote Frame Handling” on page 1205.
Several messages can try to win the bus arbitration in the same time. The message with the highest priority is sent
first. Several transfer request commands can be generated at the same time by setting MBx bits in the CAN_TCR
register. The priority is set in the PRIOR field of the CAN_MMRx register. Priority 0 is the highest priority, priority
15 is the lowest priority. Thus it is possible to use a part of the message ID to set the PRIOR field. If two mailboxes
have the same priority, the message of the mailbox with the lowest number is sent first. Thus if mailbox 0 and
mailbox 5 have the same priority and have a message to send at the same time, then the message of the mailbox
0 is sent first.
Setting the MACR bit in the CAN_MCRx register aborts the transmission. Transmission for several mailboxes can
be aborted by writing MBx fields in the CAN_MACR register. If the message is being sent when the abort
command is set, then the application is notified by the MRDY bit set and not the MABT in the CAN_MSRx register.
Otherwise, if the message has not been sent, then the MRDY and the MABT are set in the CAN_MSR register.
When the bus arbitration is lost by a mailbox message, the CAN controller tries to win the next bus arbitration with
the same message if this one still has the highest priority. Messages to be sent are re-tried automatically until they
win the bus arbitration. This feature can be disabled by setting the bit DRPT in the CAN_MR register. In this case
if the message was not sent the first time it was transmitted to the CAN transceiver, it is automatically aborted. The
MABT flag is set in the CAN_MSRx register until the next transfer command.
Figure 40-15 shows three MBx message attempts being made (MRDY of MBx set to 0).
The first MBx message is sent, the second is aborted and the last one is trying to be aborted but too late because
it has already been transmitted to the CAN transceiver.
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Figure 40-15. Transmitting Messages
40.8.3.3 Remote Frame Handling
Producer/consumer model is an efficient means of handling broadcasted messages. The push model allows a
producer to broadcast messages; the pull model allows a customer to ask for messages.
Figure 40-16. Producer / Consumer Model
In Pull Mode, a consumer transmits a remote frame to the producer. When the producer receives a remote frame,
it sends the answer accepted by one or many consumers. Using transmit and receive mailboxes, a consumer must
dedicate two mailboxes, one in Transmit Mode to send remote frames, and at least one in Receive Mode to
capture the producer’s answer. The same structure is applicable to a producer: one reception mailbox is required
to get the remote frame and one transmit mailbox to answer.
Mailboxes can be configured in Producer or Consumer Mode. A lonely mailbox can handle the remote frame and
the answer. With 8 mailboxes, the CAN controller can handle 8 independent producers/consumers.
MTCR
(CAN_MCRx)
MRDY
(CAN_MSRx)
CAN BUSMBx message
Reading CAN_MSRx
Writing CAN_MDHx &
CAN_MDLx
MBx message
MACR
(CAN_MCRx) Abort MBx message Try to Abort MBx message
MABT
(CAN_MSRx)
CAN Data Frame
CAN Remote Frame
CAN Data Frame
Indication(s)
Request
Request(s)
Indications
Response
Confirmation(s)
PUSH MODEL
PULL MODEL
Producer
Producer
Consumer
Consumer
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1206
Producer Configuration
A mailbox is in Producer Mode once the MOT field in the CAN_MMRx register has been configured. Message ID
and Message Acceptance masks must be set before Receive Mode is enabled.
After Producer Mode is enabled, the MRDY flag in the CAN_MSR register is automatically set until the first transfer
command. The software application prepares data to be sent by writing to the CAN_MDHx and the CAN_MDLx
registers, then by setting the MTCR bit in the CAN_MCRx register. Data is sent after the reception of a remote
frame as soon as it wins the bus arbitration.
The MRDY flag remains at zero as long as the message has not been sent or aborted. No access to the mailbox
data register can be done while MRDY flag is cleared. An interrupt is pending for the mailbox while the MRDY flag
is set. This interrupt can be masked according to the mailbox flag in the CAN_IMR global register.
If a remote frame is received while no data are ready to be sent (signal MRDY set in the CAN_MSRx register),
then the MMI signal is set in the CAN_MSRx register. This bit is cleared by reading the CAN_MSRx register.
The MRTR field in the CAN_MSRx register has no meaning. This field is used only when using Receive and
Receive with Overwrite modes.
After a remote frame has been received, the mailbox functions like a transmit mailbox. The message with the
highest priority is sent first. The transmitted message may be aborted by setting the MACR bit in the CAN_MCR
register. Please refer to the section “Transmission Handling” on page 1204.
Figure 40-17. Producer Handling
Consumer Configuration
A mailbox is in Consumer Mode once the MOT field in the CAN_MMRx register has been configured. Message ID
and Message Acceptance masks must be set before Receive Mode is enabled.
After Consumer Mode is enabled, the MRDY flag in the CAN_MSR register is automatically cleared until the first
transfer request command. The software application sends a remote frame by setting the MTCR bit in the
CAN_MCRx register or the MBx bit in the global CAN_TCR register. The application is notified of the answer by
the MRDY flag set in the CAN_MSRx register. The application can read the data contents in the CAN_MDHx and
CAN_MDLx registers. An interrupt is pending for the mailbox while the MRDY flag is set. This interrupt can be
masked according to the mailbox flag in the CAN_IMR global register.
The MRTR bit in the CAN_MCRx register has no effect. This field is used only when using Transmit Mode.
After a remote frame has been sent, the consumer mailbox functions as a reception mailbox. The first message
received is stored in the mailbox data registers. If other messages intended for this mailbox have been sent while
the MRDY flag is set in the CAN_MSRx register, they will be lost. The application is notified by reading the MMI
field in the CAN_MSRx register. The read operation automatically clears the MMI flag.
If several messages are answered by the Producer, the CAN controller may have one mailbox in consumer
configuration, zero or several mailboxes in Receive Mode and one mailbox in Receive with Overwrite Mode. In this
MTCR
(CAN_MCRx)
MRDY
(CAN_MSRx)
CAN BUSRemote Frame Message 1
Message 1
Message 2
(CAN_MDLx
CAN_MDHx)
MMI
(CAN_MSRx)
Remote Frame Remote Frame
Message 2
Reading CAN_MSRx
|| || XII || | Km KI— ( T f / / H H“ II IL || lk | || IR \ \ |||||||||||||||||\||||||||||||||||||| ||||||||||||||||||||1|||||||||||||| ||||||||||||||||||||l|||||||||||||||||||||||||||||||||| / | | a / \ V AtmeL
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case, the consumer mailbox must have a lower number than the Receive with Overwrite mailbox. The transfer
command can be triggered for all mailboxes at the same time by setting several MBx fields in the CAN_TCR
register.
Figure 40-18. Consumer Handling
40.8.4 CAN Controller Timing Modes
Using the free running 16-bit internal timer, the CAN controller can be set in one of the two following timing modes:
Timestamping Mode: The value of the internal timer is captured at each Start Of Frame or each End Of
Frame.
Time Triggered Mode: The mailbox transfer operation is triggered when the internal timer reaches the
mailbox trigger.
Timestamping Mode is enabled by clearing the TTM bit in the CAN_MR register. Time Triggered Mode is enabled
by setting the TTM bit in the CAN_MR register.
40.8.4.1 Timestamping Mode
Each mailbox has its own timestamp value. Each time a message is sent or received by a mailbox, the 16-bit value
MTIMESTAMP of the CAN_TIMESTP register is transferred to the LSB bits of the CAN_MSRx register. The value
read in the CAN_MSRx register corresponds to the internal timer value at the Start Of Frame or the End Of Frame
of the message handled by the mailbox.
Figure 40-19. Mailbox Timestamp
MTCR
(CAN_MCRx)
MRDY
(CAN_MSRx)
CAN BUSRemote Frame Message x
Message y
Message y
(CAN_MDLx
CAN_MDHx)
MMI
(CAN_MSRx)
Remote Frame
Message x
TEOF
(CAN_MR)
MTIMESTAMP
(CAN_MSRx)
CAN_TIM
CAN BUS
MTIMESTAMP
(CAN_MSRy)
Message 1 Message 2
Start of Frame
TIMESTAMP
(CAN_TSTP)
End of Frame
Timestamp 1
Timestamp 1
Timestamp 2
Timestamp 2
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1208
40.8.4.2 Time Triggered Mode
In Time Triggered Mode, basic cycles can be split into several time windows. A basic cycle starts with a reference
message. Each time a window is defined from the reference message, a transmit operation should occur within a
pre-defined time window. A mailbox must not win the arbitration in a previous time window, and it must not be
retried if the arbitration is lost in the time window.
Figure 40-20. Time Triggered Principle
Time Trigger Mode is enabled by setting the TTM field in the CAN_MR register. In Time Triggered Mode, as in
Timestamp Mode, the CAN_TIMESTP field captures the values of the internal counter, but the MTIMESTAMP
fields in the CAN_MSRx registers are not active and are read at 0.
Synchronization by a Reference Message
In Time Triggered Mode, the internal timer counter is automatically reset when a new message is received in the
last mailbox. This reset occurs after the reception of the End Of Frame on the rising edge of the MRDY signal in
the CAN_MSRx register. This allows synchronization of the internal timer counter with the reception of a reference
message and the start a new time window.
Transmitting within a Time Window
A time mark is defined for each mailbox. It is defined in the 16-bit MTIMEMARK field of the CAN_MMRx register.
At each internal timer clock cycle, the value of the CAN_TIM is compared with each mailbox time mark. When the
internal timer counter reaches the MTIMEMARK value, an internal timer event for the mailbox is generated for the
mailbox.
In Time Triggered Mode, transmit operations are delayed until the internal timer event for the mailbox. The
application prepares a message to be sent by setting the MTCR in the CAN_MCRx register. The message is not
sent until the CAN_TIM value is less than the MTIMEMARK value defined in the CAN_MMRx register.
If the transmit operation is failed, i.e., the message loses the bus arbitration and the next transmit attempt is
delayed until the next internal time trigger event. This prevents overlapping the next time window, but the message
is still pending and is retried in the next time window when CAN_TIM value equals the MTIMEMARK value. It is
also possible to prevent a retry by setting the DRPT field in the CAN_MR register.
Freezing the Internal Timer Counter
The internal counter can be frozen by setting TIMFRZ in the CAN_MR register. This prevents an unexpected roll-
over when the counter reaches FFFFh. When this occurs, it automatically freezes until a new reset is issued, either
due to a message received in the last mailbox or any other reset counter operations. The TOVF bit in the CAN_SR
register is set when the counter is frozen. The TOVF bit in the CAN_SR register is cleared by reading the CAN_SR
register. Depending on the corresponding interrupt mask in the CAN_IMR register, an interrupt is generated when
TOVF is set.
Reference
Message Reference
Message
Global Time
Time Cycle
Time Windows for Messages
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Figure 40-21. Time Triggered Operations
MRDY
(CAN_MSRlast_mailbox_number)
CAN_TIM
CAN BUS
MRDY
(CAN_MSRx)
End of Frame
Timer Event x MTIMEMARKx == CAN_TIM
Timer Event y
MRDY
(CAN_MSRy)
MTIMEMARKy == CAN_TIM
Cleared by software
Internal Counter Reset
Message x
Arbitration LostMessage y
Arbitration Win
Reference
Message Message y
MRDY
(CAN_MSRlast_mailbox_number)
CAN_TIM
CAN BUS
MRDY
(CAN_MSRx)
End of Frame
Timer Event x MTIMEMARKx == CAN_TIM
Cleared by software
Internal Counter Reset
Message x
Arbitration Win
Reference
Message Message x
Basic Cycle
Time Window
Basic Cycle
Time Window
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1210
40.8.5 Write Protected Registers
To prevent any single software error that may corrupt CAN behavior, the registers listed below can be write-
protected by setting the WPEN bit in the CAN Write Protection Mode Register (CAN_WPMR).
If a write access in a write-protected register is detected, then the WPVS flag in the CAN Write Protection Status
Register (CAN_WPSR) is set and the field WPVSRC indicates in which register the write access has been
attempted.
The WPVS flag is automatically reset after reading the CAN Write Protection Status Register (CAN_WPSR).
List of the write-protected registers:
Section 40.9.1 “CAN Mode Register” on page 1212
Section 40.9.6 “CAN Baudrate Register” on page 1223
Section 40.9.14 “CAN Message Mode Register” on page 1231
Section 40.9.15 “CAN Message Acceptance Mask Register” on page 1232
Section 40.9.16 “CAN Message ID Register” on page 1233
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40.9 Controller Area Network (CAN) User Interface
3. Mailbox number ranges from 0 to 7.
Table 40-6. Register Mapping
Offset Register Name Access Reset
0x0000 Mode Register CAN_MR Read-write 0x0
0x0004 Interrupt Enable Register CAN_IER Write-only -
0x0008 Interrupt Disable Register CAN_IDR Write-only -
0x000C Interrupt Mask Register CAN_IMR Read-only 0x0
0x0010 Status Register CAN_SR Read-only 0x0
0x0014 Baudrate Register CAN_BR Read-write 0x0
0x0018 Timer Register CAN_TIM Read-only 0x0
0x001C Timestamp Register CAN_TIMESTP Read-only 0x0
0x0020 Error Counter Register CAN_ECR Read-only 0x0
0x0024 Transfer Command Register CAN_TCR Write-only -
0x0028 Abort Command Register CAN_ACR Write-only -
0x002C - 0x00E0 Reserved – – –
0x00E4 Write Protect Mode Register CAN_WPMR Read-write 0x0
0x00E8 Write Protect Status Register CAN_WPSR Read-only 0x0
0x00EC - 0x01FC Reserved – – –
0x0200 + MB * 0x20 + 0x00 Mailbox Mode Register(3) CAN_MMR Read-write 0x0
0x0200 + MB * 0x20 + 0x04 Mailbox Acceptance Mask Register CAN_MAM Read-write 0x0
0x0200 + MB * 0x20 + 0x08 Mailbox ID Register CAN_MID Read-write 0x0
0x0200 + MB * 0x20 + 0x0C Mailbox Family ID Register CAN_MFID Read-only 0x0
0x0200 + MB * 0x20 + 0x10 Mailbox Status Register CAN_MSR Read-only 0x0
0x0200 + MB * 0x20 + 0x14 Mailbox Data Low Register CAN_MDL Read-write 0x0
0x0200 + MB * 0x20 + 0x18 Mailbox Data High Register CAN_MDH Read-write 0x0
0x0200 + MB * 0x20 + 0x1C Mailbox Control Register CAN_MCR Write-only -
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1212
40.9.1 CAN Mode Register
Name: CAN_MR
Address: 0x400B4000 (0), 0x400B8000 (1)
Access: Read-write
This register can only be written if the WPEN bit is cleared in ”CAN Write Protection Mode Register”.
• CANEN: CAN Controller Enable
0: The CAN Controller is disabled.
1: The CAN Controller is enabled.
• LPM: Disable/Enable Low Power Mode
w Power Mode.
1: Enable Low Power M
CAN controller enters Low Power Mode once all pending messages have been transmitted.
• ABM: Disable/Enable Autobaud/Listen mode
0: Disable Autobaud/listen mode.
1: Enable Autobaud/listen mode.
• OVL: Disable/Enable Overload Frame
0: No overload frame is generated.
1: An overload frame is generated after each successful reception for mailboxes configured in Receive with/without over-
write Mode, Producer and Consumer.
• TEOF: Timestamp messages at each end of Frame
0: The value of CAN_TIM is captured in the CAN_TIMESTP register at each Start Of Frame.
1: The value of CAN_TIM is captured in the CAN_TIMESTP register at each End Of Frame.
• TTM: Disable/Enable Time Triggered Mode
0: Time Triggered Mode is disabled.
1: Time Triggered Mode is enabled.
• TIMFRZ: Enable Timer Freeze
0: The internal timer continues to be incremented after it reached 0xFFFF.
1: The internal timer stops incrementing after reaching 0xFFFF. It is restarted after a timer reset. See “Freezing the Internal
Timer Counter” on page 1208.
31 30 29 28 27 26 25 24
––––– RXSYNC
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
DRPT TIMFRZ TTM TEOF OVL ABM LPM CANEN
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• DRPT: Disable Repeat
0: When a transmit mailbox loses the bus arbitration, the transfer request remains pending.
1: When a transmit mailbox lose the bus arbitration, the transfer request is automatically aborted. It automatically raises the
MABT and MRDT flags in the corresponding CAN_MSRx.
• RXSYNC: Reception Synchronization Stage (not readable)
This field allows configuration of the reception stage of the macrocell (for debug purposes only)
Value Name Description
0 DOUBLE_PP Rx Signal with Double Synchro Stages (2 Positive Edges)
1 DOUBLE_PN Rx Signal with Double Synchro Stages (One Positive Edge and One Negative Edge)
2 SINGLE_P Rx Signal with Single Synchro Stage (Positive Edge)
3 NONE Rx Signal with No Synchro Stage
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1214
40.9.2 CAN Interrupt Enable Register
Name: CAN_IER
Address: 0x400B4004 (0), 0x400B8004 (1)
Access: Write-only
• MBx: Mailbox x Interrupt Enable
0: No effect.
1: Enable Mailbox x interrupt.
• ERRA: Error Active Mode Interrupt Enable
0: No effect.
1: Enable ERRA interrupt.
• WARN: Warning Limit Interrupt Enable
0: No effect.
1: Enable WARN interrupt.
• ERRP: Error Passive Mode Interrupt Enable
0: No effect.
1: Enable ERRP interrupt.
• BOFF: Bus Off Mode Interrupt Enable
0: No effect.
1: Enable BOFF interrupt.
• SLEEP: Sleep Interrupt Enable
0: No effect.
1: Enable SLEEP interrupt.
• WAKEUP: Wakeup Interrupt Enable
0: No effect.
1: Enable SLEEP interrupt.
• TOVF: Timer Overflow Interrupt Enable
0: No effect.
1: Enable TOVF interrupt.
31 30 29 28 27 26 25 24
– – – BERR FERR AERR SERR CERR
23 22 21 20 19 18 17 16
TSTP TOVF WAKEUP SLEEP BOFF ERRP WARN ERRA
15 14 13 12 11 10 9 8
––––––––
76543210
MB7 MB6 MB5 MB4 MB3 MB2 MB1 MB0
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• TSTP: TimeStamp Interrupt Enable
0: No effect.
1: Enable TSTP interrupt.
• CERR: CRC Error Interrupt Enable
0: No effect.
1: Enable CRC Error interrupt.
• SERR: Stuffing Error Interrupt Enable
0: No effect.
1: Enable Stuffing Error interrupt.
• AERR: Acknowledgment Error Interrupt Enable
0: No effect.
1: Enable Acknowledgment Error interrupt.
• FERR: Form Error Interrupt Enable
0: No effect.
1: Enable Form Error interrupt.
• BERR: Bit Error Interrupt Enable
0: No effect.
1: Enable Bit Error interrupt.
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1216
40.9.3 CAN Interrupt Disable Register
Name: CAN_IDR
Address: 0x400B4008 (0), 0x400B8008 (1)
Access: Write-only
• MBx: Mailbox x Interrupt Disable
0: No effect.
1: Disable Mailbox x interrupt.
• ERRA: Error Active Mode Interrupt Disable
0: No effect.
1: Disable ERRA interrupt.
• WARN: Warning Limit Interrupt Disable
0: No effect.
1: Disable WARN interrupt.
• ERRP: Error Passive Mode Interrupt Disable
0: No effect.
1: Disable ERRP interrupt.
• BOFF: Bus Off Mode Interrupt Disable
0: No effect.
1: Disable BOFF interrupt.
• SLEEP: Sleep Interrupt Disable
0: No effect.
1: Disable SLEEP interrupt.
• WAKEUP: Wakeup Interrupt Disable
0: No effect.
1: Disable WAKEUP interrupt.
• TOVF: Timer Overflow Interrupt
0: No effect.
1: Disable TOVF interrupt.
31 30 29 28 27 26 25 24
– – – BERR FERR AERR SERR CERR
23 22 21 20 19 18 17 16
TSTP TOVF WAKEUP SLEEP BOFF ERRP WARN ERRA
15 14 13 12 11 10 9 8
––––––––
76543210
MB7 MB6 MB5 MB4 MB3 MB2 MB1 MB0
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• TSTP: TimeStamp Interrupt Disable
0: No effect.
1: Disable TSTP interrupt.
• CERR: CRC Error Interrupt Disable
0: No effect.
1: Disable CRC Error interrupt.
• SERR: Stuffing Error Interrupt Disable
0: No effect.
1: Disable Stuffing Error interrupt.
• AERR: Acknowledgment Error Interrupt Disable
0: No effect.
1: Disable Acknowledgment Error interrupt.
• FERR: Form Error Interrupt Disable
0: No effect.
1: Disable Form Error interrupt.
• BERR: Bit Error Interrupt Disable
0: No effect.
1: Disable Bit Error interrupt.
SAM3X / SAM3A [DATASHEET]
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1218
40.9.4 CAN Interrupt Mask Register
Name: CAN_IMR
Address: 0x400B400C (0), 0x400B800C (1)
Access: Read-only
• MBx: Mailbox x Interrupt Mask
0: Mailbox x interrupt is disabled.
1: Mailbox x interrupt is enabled.
• ERRA: Error Active Mode Interrupt Mask
0: ERRA interrupt is disabled.
1: ERRA interrupt is enabled.
• WARN: Warning Limit Interrupt Mask
0: Warning Limit interrupt is disabled.
1: Warning Limit interrupt is enabled.
• ERRP: Error Passive Mode Interrupt Mask
0: ERRP interrupt is disabled.
1: ERRP interrupt is enabled.
• BOFF: Bus Off Mode Interrupt Mask
0: BOFF interrupt is disabled.
1: BOFF interrupt is enabled.
• SLEEP: Sleep Interrupt Mask
0: SLEEP interrupt is disabled.
1: SLEEP interrupt is enabled.
• WAKEUP: Wakeup Interrupt Mask
0: WAKEUP interrupt is disabled.
1: WAKEUP interrupt is enabled.
• TOVF: Timer Overflow Interrupt Mask
0: TOVF interrupt is disabled.
1: TOVF interrupt is enabled.
31 30 29 28 27 26 25 24
– – – BERR FERR AERR SERR CERR
23 22 21 20 19 18 17 16
TSTP TOVF WAKEUP SLEEP BOFF ERRP WARN ERRA
15 14 13 12 11 10 9 8
––––––––
76543210
MB7 MB6 MB5 MB4 MB3 MB2 MB1 MB0
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• TSTP: Timestamp Interrupt Mask
0: TSTP interrupt is disabled.
1: TSTP interrupt is enabled.
• CERR: CRC Error Interrupt Mask
0: CRC Error interrupt is disabled.
1: CRC Error interrupt is enabled.
• SERR: Stuffing Error Interrupt Mask
0: Bit Stuffing Error interrupt is disabled.
1: Bit Stuffing Error interrupt is enabled.
• AERR: Acknowledgment Error Interrupt Mask
0: Acknowledgment Error interrupt is disabled.
1: Acknowledgment Error interrupt is enabled.
• FERR: Form Error Interrupt Mask
0: Form Error interrupt is disabled.
1: Form Error interrupt is enabled.
• BERR: Bit Error Interrupt Mask
0: Bit Error interrupt is disabled.
1: Bit Error interrupt is enabled.
SAM3X / SAM3A [DATASHEET]
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1220
40.9.5 CAN Status Register
Name: CAN_SR
Address: 0x400B4010 (0), 0x400B8010 (1)
Access: Read-only
• MBx: Mailbox x Event
0: No event occurred on Mailbox x.
1: An event occurred on Mailbox x.
An event corresponds to MRDY, MABT fields in the CAN_MSRx register.
• ERRA: Error Active Mode
0: CAN controller is not in Error Active Mode.
1: CAN controller is in Error Active Mode.
This flag is set depending on TEC and REC counter values. It is set when a node is neither in Error Passive Mode nor in
Bus Off Mode.
This flag is automatically reset when the above condition is not satisfied. Refer to Section “Error Interrupt Handler” on
page 1196 for more information.
• WARN: Warning Limit
0: CAN controller Warning Limit is not reached.
1: CAN controller Warning Limit is reached.
This flag is set depending on TEC and REC counter values. It is set when at least one of the counter values exceeds 96.
This flag is automatically reset when above the condition is not satisfied. Refer to Section “Error Interrupt Handler” on
page 1196 for more information.
• ERRP: Error Passive Mode
0: CAN controller is not in Error Passive Mode.
1: CAN controller is in Error Passive Mode.
This flag is set depending on TEC and REC counters values.
A node is in error passive state when TEC counter is greater or equal to 128 (decimal) or when the REC counter is greater
or equal to 128 (decimal).
This flag is automatically reset when the above condition is not satisfied. Refer to Section “Error Interrupt Handler” on
page 1196 for more information.
31 30 29 28 27 26 25 24
OVLSY TBSY RBSY BERR FERR AERR SERR CERR
23 22 21 20 19 18 17 16
TSTP TOVF WAKEUP SLEEP BOFF ERRP WARN ERRA
15 14 13 12 11 10 9 8
––––––––
76543210
MB7 MB6 MB5 MB4 MB3 MB2 MB1 MB0
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• BOFF: Bus Off Mode
0: CAN controller is not in Bus Off Mode.
1: CAN controller is in Bus Off Mode.
This flag is set depending on TEC counter value. A node is in bus off state when TEC counter is greater or equal to 256
(decimal).
This flag is automatically reset when the above condition is not satisfied. Refer to Section “Error Interrupt Handler” on
page 1196 for more information.
• SLEEP: CAN controller in Low power Mode
0: CAN controller is not in low power mode.
1: CAN controller is in low power mode.
This flag is automatically reset when Low power mode is disabled
• WAKEUP: CAN controller is not in Low power Mode
0: CAN controller is in low power mode.
1: CAN controller is not in low power mode.
When a WAKEUP event occurs, the CAN controller is synchronized with the bus activity. Messages can be transmitted or
received. The CAN controller clock must be available when a WAKEUP event occurs. This flag is automatically reset when
the CAN Controller enters Low Power mode.
• TOVF: Timer Overflow
0: The timer has not rolled-over FFFFh to 0000h.
1: The timer rolls-over FFFFh to 0000h.
This flag is automatically cleared by reading CAN_SR register.
• TSTP Timestamp
0: No bus activity has been detected.
1: A start of frame or an end of frame has been detected (according to the TEOF field in the CAN_MR register).
This flag is automatically cleared by reading the CAN_SR register.
• CERR: Mailbox CRC Error
0: No CRC error occurred during a previous transfer.
1: A CRC error occurred during a previous transfer.
A CRC error has been detected during last reception.
This flag is automatically cleared by reading CAN_SR register.
• SERR: Mailbox Stuffing Error
0: No stuffing error occurred during a previous transfer.
1: A stuffing error occurred during a previous transfer.
A form error results from the detection of more than five consecutive bit with the same polarity.
This flag is automatically cleared by reading CAN_SR register.
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• AERR: Acknowledgment Error
0: No acknowledgment error occurred during a previous transfer.
1: An acknowledgment error occurred during a previous transfer.
An acknowledgment error is detected when no detection of the dominant bit in the acknowledge slot occurs.
This flag is automatically cleared by reading CAN_SR register.
• FERR: Form Error
0: No form error occurred during a previous transfer
1: A form error occurred during a previous transfer
A form error results from violations on one or more of the fixed form of the following bit fields:
– CRC delimiter
– ACK delimiter
– End of frame
– Error delimiter
–Overload delimiter
This flag is automatically cleared by reading CAN_SR register.
• BERR: Bit Error
0: No bit error occurred during a previous transfer.
1: A bit error occurred during a previous transfer.
A bit error is set when the bit value monitored on the line is different from the bit value sent.
This flag is automatically cleared by reading CAN_SR register.
• RBSY: Receiver busy
0: CAN receiver is not receiving a frame.
1: CAN receiver is receiving a frame.
Receiver busy. This status bit is set by hardware while CAN receiver is acquiring or monitoring a frame (remote, data, over-
load or error frame). It is automatically reset when CAN is not receiving.
• TBSY: Transmitter busy
0: CAN transmitter is not transmitting a frame.
1: CAN transmitter is transmitting a frame.
Transmitter busy. This status bit is set by hardware while CAN transmitter is generating a frame (remote, data, overload or
error frame). It is automatically reset when CAN is not transmitting.
• OVLSY: Overload busy
0: CAN transmitter is not transmitting an overload frame.
1: CAN transmitter is transmitting a overload frame.
It is automatically reset when the bus is not transmitting an overload frame.
><( m=""><(><(><( (="" )/="" atmel="">
1223
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
40.9.6 CAN Baudrate Register
Name: CAN_BR
Address: 0x400B4014 (0), 0x400B8014 (1)
Access: Read-write
This register can only be written if the WPEN bit is cleared in ”CAN Write Protection Mode Register”.
Any modification on one of the fields of the CAN_BR register must be done while CAN module is disabled.
To compute the different Bit Timings, please refer to the Section 40.7.4.1 “CAN Bit Timing Configuration” on page 1192.
• PHASE2: Phase 2 segment
This phase is used to compensate the edge phase error.
Warning: PHASE2 value must be different from 0.
• PHASE1: Phase 1 segment
This phase is used to compensate for edge phase error.
• PROPAG: Programming time segment
This part of the bit time is used to compensate for the physical delay times within the network.
• SJW: Re-synchronization jump width
To compensate for phase shifts between clock oscillators of different controllers on bus. The controller must re-synchro-
nize on any relevant signal edge of the current transmission. The synchronization jump width defines the maximum of
clock cycles a bit period may be shortened or lengthened by re-synchronization.
• BRP: Baudrate Prescaler.
This field allows user to program the period of the CAN system clock to determine the individual bit timing.
The BRP field must be within the range [1, 0x7F], i.e., BRP = 0 is not authorized.
• SMP: Sampling Mode
0 (ONCE): The incoming bit stream is sampled once at sample point.
1 (THREE): The incoming bit stream is sampled three times with a period of a MCK clock period, centered on sample point.
SMP Sampling Mode is automatically disabled if BRP = 0.
31 30 29 28 27 26 25 24
–––––––SMP
23 22 21 20 19 18 17 16
–BRP
15 14 13 12 11 10 9 8
– – SJW – PROPAG
76543210
– PHASE1 – PHASE2
tPHS2 tCSC PHASE2 1+()×=
tPHS1 tCSC PHASE1 1+()×=
tPRS tCSC PROPAG 1+()×=
tSJW tCSC SJW 1+()×=
tCSC BRP 1+()MCK⁄=
SAM3X / SAM3A [DATASHEET]
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1224
40.9.7 CAN Timer Register
Name: CAN_TIM
Address: 0x400B4018 (0), 0x400B8018 (1)
Access: Read-only
• TIMER: Timer
This field represents the internal CAN controller 16-bit timer value.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TIMER
76543210
TIMER
1225
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
40.9.8 CAN Timestamp Register
Name: CAN_TIMESTP
Address: 0x400B401C (0), 0x400B801C (1)
Access: Read-only
• MTIMESTAMP: Timestamp
This field carries the value of the internal CAN controller 16-bit timer value at the start or end of frame.
If the TEOF bit is cleared in the CAN_MR register, the internal Timer Counter value is captured in the MTIMESTAMP field
at each start of frame else the value is captured at each end of frame. When the value is captured, the TSTP flag is set in
the CAN_SR register. If the TSTP mask in the CAN_IMR register is set, an interrupt is generated while TSTP flag is set in
the CAN_SR register. This flag is cleared by reading the CAN_SR register.
Note: The CAN_TIMESTP register is reset when the CAN is disabled then enabled thanks to the CANEN bit in the CAN_MR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
MTIMESTAMP
76543210
MTIMESTAMP
SAM3X / SAM3A [DATASHEET]
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1226
40.9.9 CAN Error Counter Register
Name: CAN_ECR
Address: 0x400B4020 (0), 0x400B8020 (1)
Access: Read-only
• REC: Receive Error Counter
When a receiver detects an error, REC will be increased by one, except when the detected error is a BIT ERROR while
sending an ACTIVE ERROR FLAG or an OVERLOAD FLAG.
When a receiver detects a dominant bit as the first bit after sending an ERROR FLAG, REC is increased by 8.
When a receiver detects a BIT ERROR while sending an ACTIVE ERROR FLAG, REC is increased by 8.
Any node tolerates up to 7 consecutive dominant bits after sending an ACTIVE ERROR FLAG, PASSIVE ERROR FLAG or
OVERLOAD FLAG. After detecting the 14th consecutive dominant bit (in case of an ACTIVE ERROR FLAG or an OVER-
LOAD FLAG) or after detecting the 8th consecutive dominant bit following a PASSIVE ERROR FLAG, and after each
sequence of additional eight consecutive dominant bits, each receiver increases its REC by 8.
After successful reception of a message, REC is decreased by 1 if it was between 1 and 127. If REC was 0, it stays 0, and
if it was greater than 127, then it is set to a value between 119 and 127.
• TEC: Transmit Error Counter
When a transmitter sends an ERROR FLAG, TEC is increased by 8 except when
– the transmitter is error passive and detects an ACKNOWLEDGMENT ERROR because of not detecting a
dominant ACK and does not detect a dominant bit while sending its PASSIVE ERROR FLAG.
– the transmitter sends an ERROR FLAG because a STUFF ERROR occurred during arbitration and should
have been recessive and has been sent as recessive but monitored as dominant.
When a transmitter detects a BIT ERROR while sending an ACTIVE ERROR FLAG or an OVERLOAD FLAG, the TEC will
be increased by 8.
Any node tolerates up to 7 consecutive dominant bits after sending an ACTIVE ERROR FLAG, PASSIVE ERROR FLAG or
OVERLOAD FLAG. After detecting the 14th consecutive dominant bit (in case of an ACTIVE ERROR FLAG or an OVER-
LOAD FLAG) or after detecting the 8th consecutive dominant bit following a PASSIVE ERROR FLAG, and after each
sequence of additional eight consecutive dominant bits every transmitter increases its TEC by 8.
After a successful transmission the TEC is decreased by 1 unless it was already 0.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
TEC
15 14 13 12 11 10 9 8
––––––––
76543210
REC
1227
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
40.9.10 CAN Transfer Command Register
Name: CAN_TCR
Address: 0x400B4024 (0), 0x400B8024 (1)
Access: Write-only
This register initializes several transfer requests at the same time.
• MBx: Transfer Request for Mailbox x
This flag clears the MRDY and MABT flags in the corresponding CAN_MSRx register.
When several mailboxes are requested to be transmitted simultaneously, they are transmitted in turn, starting with the
mailbox with the highest priority. If several mailboxes have the same priority, then the mailbox with the lowest number is
sent first (i.e., MB0 will be transferred before MB1).
• TIMRST: Timer Reset
Resets the internal timer counter. If the internal timer counter is frozen, this command automatically re-enables it. This
command is useful in Time Triggered mode.
31 30 29 28 27 26 25 24
TIMRST–––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
MB7 MB6 MB5 MB4 MB3 MB2 MB1 MB0
Mailbox Object Type Description
Receive It receives the next message.
Receive with overwrite This triggers a new reception.
Transmit Sends data prepared in the mailbox as soon as possible.
Consumer Sends a remote frame.
Producer Sends data prepared in the mailbox after receiving a remote frame from a
consumer.
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40.9.11 CAN Abort Command Register
Name: CAN_ACR
Address: 0x400B4028 (0), 0x400B8028 (1)
Access: Write-only
This register initializes several abort requests at the same time.
• MBx: Abort Request for Mailbox x
It is possible to set MACR field (in the CAN_MCRx register) for each mailbox.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
MB7 MB6 MB5 MB4 MB3 MB2 MB1 MB0
Mailbox Object Type Description
Receive No action
Receive with overwrite No action
Transmit Cancels transfer request if the message has not been transmitted to the
CAN transceiver.
Consumer Cancels the current transfer before the remote frame has been sent.
Producer Cancels the current transfer. The next remote frame is not serviced.
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40.9.12 CAN Write Protection Mode Register
Name: CAN_WPMR
Address: 0x400B40E4 (0), 0x400B80E4 (1)
Access: Read-write
• WPEN: Write Protection Enable
0: The Write Protection is Disabled
1: The Write Protection is Enabled
• WPKEY: SPI Write Protection Key Password
If a value is written in WPEN, the value is taken into account only if WPKEY is written with “CAN” (CAN written in ASCII
Code, ie 0x43414E in hexadecimal).
Protects the registers:
Section 40.9.1 “CAN Mode Register” on page 1212
Section 40.9.6 “CAN Baudrate Register” on page 1223
Section 40.9.14 “CAN Message Mode Register” on page 1231
Section 40.9.15 “CAN Message Acceptance Mask Register” on page 1232
Section 40.9.16 “CAN Message ID Register” on page 1233
3130292827 26 25 24
WPKEY
2322 21 20 19 1817 16
WPKEY
15 14 1312 11 10 9 8
WPKEY
76543210
-------WPEN
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1230
40.9.13 CAN Write Protection Status Register
Name: CAN_WPSR
Address: 0x400B40E8 (0), 0x400B80E8 (1)
Access: Read-only
• WPVS: Write Protection Violation Status
0 = No Write Protect Violation has occurred since the last read of the CAN_WPSR register.
1 = A Write Protect Violation has occurred since the last read of the CAN_WPSR register. If this violation is an unauthor-
ized attempt to write a protected register, the associated violation is reported into field WPVSRC.
• WPVSRC: Write Protection Violation Source
This Field indicates the offset of the register concerned by the violation
3130292827 26 25 24
--------
2322 21 20 19 1817 16
--------
15 14 1312 11 10 9 8
WPVSRC
76543210
-------WPVS
1231
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
40.9.14 CAN Message Mode Register
Name: CAN_MMRx [x=0..7]
Address: 0x400B4200 (0)[0], 0x400B4220 (0)[1], 0x400B4240 (0)[2], 0x400B4260 (0)[3], 0x400B4280 (0)[4],
0x400B42A0 (0)[5], 0x400B42C0 (0)[6], 0x400B42E0 (0)[7], 0x400B8200 (1)[0], 0x400B8220 (1)[1], 0x400B8240 (1)[2],
0x400B8260 (1)[3], 0x400B8280 (1)[4], 0x400B82A0 (1)[5], 0x400B82C0 (1)[6], 0x400B82E0 (1)[7]
Access: Read-write
This register can only be written if the WPEN bit is cleared in ”CAN Write Protection Mode Register”.
• MTIMEMARK: Mailbox Timemark
This field is active in Time Triggered Mode. Transmit operations are allowed when the internal timer counter reaches the
Mailbox Timemark. See “Transmitting within a Time Window” on page 1208.
In Timestamp Mode, MTIMEMARK is set to 0.
• PRIOR: Mailbox Priority
This field has no effect in receive and receive with overwrite modes. In these modes, the mailbox with the lowest number is
serviced first.
When several mailboxes try to transmit a message at the same time, the mailbox with the highest priority is serviced first. If
several mailboxes have the same priority, the mailbox with the lowest number is serviced first (i.e., MBx0 is serviced before
MBx 15 if they have the same priority).
• MOT: Mailbox Object Type
This field allows the user to define the type of the mailbox. All mailboxes are independently configurable. Five different
types are possible for each mailbox:
31 30 29 28 27 26 25 24
––––– MOT
23 22 21 20 19 18 17 16
–––– PRIOR
15 14 13 12 11 10 9 8
MTIMEMARK
76543210
MTIMEMARK
Value Name Description
0 MB_DISABLED Mailbox is disabled. This prevents receiving or transmitting any messages with this
mailbox.
1MB_RX Reception Mailbox. Mailbox is configured for reception. If a message is received
while the mailbox data register is full, it is discarded.
2 MB_RX_OVERWRITE Reception mailbox with overwrite. Mailbox is configured for reception. If a message
is received while the mailbox is full, it overwrites the previous message.
3 MB_TX Transmit mailbox. Mailbox is configured for transmission.
4 MB_CONSUMER Consumer Mailbox. Mailbox is configured in reception but behaves as a Transmit
Mailbox, i.e., it sends a remote frame and waits for an answer.
5 MB_PRODUCER Producer Mailbox. Mailbox is configured in transmission but also behaves like a
reception mailbox, i.e., it waits to receive a Remote Frame before sending its
contents.
6–Reserved
SAM3X / SAM3A [DATASHEET]
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1232
40.9.15 CAN Message Acceptance Mask Register
Name: CAN_MAMx [x=0..7]
Address: 0x400B4204 (0)[0], 0x400B4224 (0)[1], 0x400B4244 (0)[2], 0x400B4264 (0)[3], 0x400B4284 (0)[4],
0x400B42A4 (0)[5], 0x400B42C4 (0)[6], 0x400B42E4 (0)[7], 0x400B8204 (1)[0], 0x400B8224 (1)[1], 0x400B8244 (1)[2],
0x400B8264 (1)[3], 0x400B8284 (1)[4], 0x400B82A4 (1)[5], 0x400B82C4 (1)[6], 0x400B82E4 (1)[7]
Access: Read-write
This register can only be written if the WPEN bit is cleared in ”CAN Write Protection Mode Register”.
To prevent concurrent access with the internal CAN core, the application must disable the mailbox before writing to
CAN_MAMx registers.
• MIDvB: Complementary bits for identifier in extended frame mode
Acceptance mask for corresponding field of the message IDvB register of the mailbox.
• MIDvA: Identifier for standard frame mode
Acceptance mask for corresponding field of the message IDvA register of the mailbox.
• MIDE: Identifier Version
0: Compares IDvA from the received frame with the CAN_MIDx register masked with CAN_MAMx register.
1: Compares IDvA and IDvB from the received frame with the CAN_MIDx register masked with CAN_MAMx register.
31 30 29 28 27 26 25 24
– – MIDE MIDvA
23 22 21 20 19 18 17 16
MIDvA MIDvB
15 14 13 12 11 10 9 8
MIDvB
76543210
MIDvB
1233
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40.9.16 CAN Message ID Register
Name: CAN_MIDx [x=0..7]
Address: 0x400B4208 (0)[0], 0x400B4228 (0)[1], 0x400B4248 (0)[2], 0x400B4268 (0)[3], 0x400B4288 (0)[4],
0x400B42A8 (0)[5], 0x400B42C8 (0)[6], 0x400B42E8 (0)[7], 0x400B8208 (1)[0], 0x400B8228 (1)[1], 0x400B8248 (1)[2],
0x400B8268 (1)[3], 0x400B8288 (1)[4], 0x400B82A8 (1)[5], 0x400B82C8 (1)[6], 0x400B82E8 (1)[7]
Access: Read-write
This register can only be written if the WPEN bit is cleared in ”CAN Write Protection Mode Register”.
To prevent concurrent access with the internal CAN core, the application must disable the mailbox before writing to
CAN_MIDx registers.
• MIDvB: Complementary bits for identifier in extended frame mode
If MIDE is cleared, MIDvB value is 0.
• MIDE: Identifier Version
This bit allows the user to define the version of messages processed by the mailbox. If set, mailbox is dealing with version
2.0 Part B messages; otherwise, mailbox is dealing with version 2.0 Part A messages.
• MIDvA: Identifier for standard frame mode
31 30 29 28 27 26 25 24
– – MIDE MIDvA
23 22 21 20 19 18 17 16
MIDvA MIDvB
15 14 13 12 11 10 9 8
MIDvB
76543210
MIDvB
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1234
40.9.17 CAN Message Family ID Register
Name: CAN_MFIDx [x=0..7]
Address: 0x400B420C (0)[0], 0x400B422C (0)[1], 0x400B424C (0)[2], 0x400B426C (0)[3], 0x400B428C (0)[4],
0x400B42AC (0)[5], 0x400B42CC (0)[6], 0x400B42EC (0)[7], 0x400B820C (1)[0], 0x400B822C (1)[1], 0x400B824C (1)[2],
0x400B826C (1)[3], 0x400B828C (1)[4], 0x400B82AC (1)[5], 0x400B82CC (1)[6], 0x400B82EC (1)[7]
Access: Read-only
• MFID: Family ID
This field contains the concatenation of CAN_MIDx register bits masked by the CAN_MAMx register. This field is useful to
speed up message ID decoding. The message acceptance procedure is described below.
As an example:
CAN_MIDx = 0x305A4321
CAN_MAMx = 0x3FF0F0FF
CAN_MFIDx = 0x000000A3
31 30 29 28 27 26 25 24
––– MFID
23 22 21 20 19 18 17 16
MFID
15 14 13 12 11 10 9 8
MFID
76543210
MFID
1235
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
40.9.18 CAN Message Status Register
Name: CAN_MSRx [x=0..7]
Address: 0x400B4210 (0)[0], 0x400B4230 (0)[1], 0x400B4250 (0)[2], 0x400B4270 (0)[3], 0x400B4290 (0)[4],
0x400B42B0 (0)[5], 0x400B42D0 (0)[6], 0x400B42F0 (0)[7], 0x400B8210 (1)[0], 0x400B8230 (1)[1], 0x400B8250 (1)[2],
0x400B8270 (1)[3], 0x400B8290 (1)[4], 0x400B82B0 (1)[5], 0x400B82D0 (1)[6], 0x400B82F0 (1)[7]
Access: Read-only
These register fields are updated each time a message transfer is received or aborted.
MMI is cleared by reading the CAN_MSRx register.
MRDY, MABT are cleared by writing MTCR or MACR in the CAN_MCRx register.
Warning: MRTR and MDLC state depends partly on the mailbox object type.
• MTIMESTAMP: Timer value
This field is updated only when time-triggered operations are disabled (TTM cleared in CAN_MR register). If the TEOF field
in the CAN_MR register is cleared, TIMESTAMP is the internal timer value at the start of frame of the last message
received or sent by the mailbox. If the TEOF field in the CAN_MR register is set, TIMESTAMP is the internal timer value at
the end of frame of the last message received or sent by the mailbox.
In Time Triggered Mode, MTIMESTAMP is set to 0.
• MDLC: Mailbox Data Length Code
• MRTR: Mailbox Remote Transmission Request
31 30 29 28 27 26 25 24
–––––––
MMI
23 22 21 20 19 18 17 16
MRDY MABT – MRTR MDLC
15 14 13 12 11 10 9 8
MTIMESTAMP
76543210
MTIMESTAMP
Mailbox Object Type Description
Receive Length of the first mailbox message received
Receive with overwrite Length of the last mailbox message received
Transmit No action
Consumer Length of the mailbox message received
Producer Length of the mailbox message to be sent after the remote frame reception
Mailbox Object Type Description
Receive The first frame received has the RTR bit set.
Receive with overwrite The last frame received has the RTR bit set.
Transmit Reserved
Consumer Reserved. After setting the MOT field in the CAN_MMR, MRTR is reset to 1.
Producer Reserved. After setting the MOT field in the CAN_MMR, MRTR is reset to 0.
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1236
• MABT: Mailbox Message Abort
An interrupt is triggered when MABT is set.
0: Previous transfer is not aborted.
1: Previous transfer has been aborted.
This flag is cleared by writing to CAN_MCRx register
• MRDY: Mailbox Ready
An interrupt is triggered when MRDY is set.
0: Mailbox data registers can not be read/written by the software application. CAN_MDx are locked by the CAN_MDx.
1: Mailbox data registers can be read/written by the software application.
This flag is cleared by writing to CAN_MCRx register.
Mailbox Object Type Description
Receive Reserved
Receive with overwrite Reserved
Transmit Previous transfer has been aborted
Consumer The remote frame transfer request has been aborted.
Producer The response to the remote frame transfer has been aborted.
Mailbox Object Type Description
Receive
At least one message has been received since the last mailbox transfer order. Data from the first frame
received can be read in the CAN_MDxx registers.
After setting the MOT field in the CAN_MMR, MRDY is reset to 0.
Receive with overwrite
At least one frame has been received since the last mailbox transfer order. Data from the last frame
received can be read in the CAN_MDxx registers.
After setting the MOT field in the CAN_MMR, MRDY is reset to 0.
Transmit Mailbox data have been transmitted.
After setting the MOT field in the CAN_MMR, MRDY is reset to 1.
Consumer
At least one message has been received since the last mailbox transfer order. Data from the first message
received can be read in the CAN_MDxx registers.
After setting the MOT field in the CAN_MMR, MRDY is reset to 0.
Producer A remote frame has been received, mailbox data have been transmitted.
After setting the MOT field in the CAN_MMR, MRDY is reset to 1.
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• MMI: Mailbox Message Ignored
0: No message has been ignored during the previous transfer
1: At least one message has been ignored during the previous transfer
Cleared by reading the CAN_MSRx register.
Mailbox Object Type Description
Receive Set when at least two messages intended for the mailbox have been sent. The first one is available in the
mailbox data register. Others have been ignored. A mailbox with a lower priority may have accepted the
message.
Receive with overwrite Set when at least two messages intended for the mailbox have been sent. The last one is available in the
mailbox data register. Previous ones have been lost.
Transmit Reserved
Consumer A remote frame has been sent by the mailbox but several messages have been received. The first one is
available in the mailbox data register. Others have been ignored. Another mailbox with a lower priority may
have accepted the message.
Producer A remote frame has been received, but no data are available to be sent.
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40.9.19 CAN Message Data Low Register
Name: CAN_MDLx [x=0..7]
Address: 0x400B4214 (0)[0], 0x400B4234 (0)[1], 0x400B4254 (0)[2], 0x400B4274 (0)[3], 0x400B4294 (0)[4],
0x400B42B4 (0)[5], 0x400B42D4 (0)[6], 0x400B42F4 (0)[7], 0x400B8214 (1)[0], 0x400B8234 (1)[1], 0x400B8254 (1)[2],
0x400B8274 (1)[3], 0x400B8294 (1)[4], 0x400B82B4 (1)[5], 0x400B82D4 (1)[6], 0x400B82F4 (1)[7]
Access: Read-write
• MDL: Message Data Low Value
When MRDY field is set in the CAN_MSRx register, the lower 32 bits of a received message can be read or written by the
software application. Otherwise, the MDL value is locked by the CAN controller to send/receive a new message.
In Receive with overwrite, the CAN controller may modify MDL value while the software application reads MDH and MDL
registers. To check that MDH and MDL do not belong to different messages, the application has to check the MMI field in
the CAN_MSRx register. In this mode, the software application must re-read CAN_MDH and CAN_MDL, while the MMI bit
in the CAN_MSRx register is set.
Bytes are received/sent on the bus in the following order:
1. CAN_MDL[7:0]
2. CAN_MDL[15:8]
3.CAN_MDL[23:16]
4. CAN_MDL[31:24]
5. CAN_MDH[7:0]
6. CAN_MDH[15:8]
7. CAN_MDH[23:16]
8.CAN_MDH[31:24]
31 30 29 28 27 26 25 24
MDL
23 22 21 20 19 18 17 16
MDL
15 14 13 12 11 10 9 8
MDL
76543210
MDL
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40.9.20 CAN Message Data High Register
Name: CAN_MDHx [x=0..7]
Address: 0x400B4218 (0)[0], 0x400B4238 (0)[1], 0x400B4258 (0)[2], 0x400B4278 (0)[3], 0x400B4298 (0)[4],
0x400B42B8 (0)[5], 0x400B42D8 (0)[6], 0x400B42F8 (0)[7], 0x400B8218 (1)[0], 0x400B8238 (1)[1], 0x400B8258 (1)[2],
0x400B8278 (1)[3], 0x400B8298 (1)[4], 0x400B82B8 (1)[5], 0x400B82D8 (1)[6], 0x400B82F8 (1)[7]
Access: Read-write
• MDH: Message Data High Value
When MRDY field is set in the CAN_MSRx register, the upper 32 bits of a received message are read or written by the soft-
ware application. Otherwise, the MDH value is locked by the CAN controller to send/receive a new message.
In Receive with overwrite, the CAN controller may modify MDH value while the software application reads MDH and MDL
registers. To check that MDH and MDL do not belong to different messages, the application has to check the MMI field in
the CAN_MSRx register. In this mode, the software application must re-read CAN_MDH and CAN_MDL, while the MMI bit
in the CAN_MSRx register is set.
Bytes are received/sent on the bus in the following order:
1. CAN_MDL[7:0]
2. CAN_MDL[15:8]
3.CAN_MDL[23:16]
4. CAN_MDL[31:24]
5. CAN_MDH[7:0]
6. CAN_MDH[15:8]
7. CAN_MDH[23:16]
8.CAN_MDH[31:24]
31 30 29 28 27 26 25 24
MDH
23 22 21 20 19 18 17 16
MDH
15 14 13 12 11 10 9 8
MDH
76543210
MDH
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40.9.21 CAN Message Control Register
Name: CAN_MCRx [x=0..7]
Address: 0x400B421C (0)[0], 0x400B423C (0)[1], 0x400B425C (0)[2], 0x400B427C (0)[3], 0x400B429C (0)[4],
0x400B42BC (0)[5], 0x400B42DC (0)[6], 0x400B42FC (0)[7], 0x400B821C (1)[0], 0x400B823C (1)[1], 0x400B825C (1)[2],
0x400B827C (1)[3], 0x400B829C (1)[4], 0x400B82BC (1)[5], 0x400B82DC (1)[6], 0x400B82FC (1)[7]
Access: Write-only
• MDLC: Mailbox Data Length Code
• MRTR: Mailbox Remote Transmission Request
Consumer situations can be handled automatically by setting the mailbox object type in Consumer. This requires only one
mailbox.
It can also be handled using two mailboxes, one in reception, the other in transmission. The MRTR and the MTCR bits
must be set in the same time.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
MTCR MACR – MRTR MDLC
15 14 13 12 11 10 9 8
––––––––
76543210
––––––––
Mailbox Object Type Description
Receive No action.
Receive with overwrite No action.
Transmit Length of the mailbox message.
Consumer No action.
Producer Length of the mailbox message to be sent after the remote frame
reception.
Mailbox Object Type Description
Receive No action
Receive with overwrite No action
Transmit Set the RTR bit in the sent frame
Consumer No action, the RTR bit in the sent frame is set automatically
Producer No action
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• MACR: Abort Request for Mailbox x
It is possible to set MACR field for several mailboxes in the same time, setting several bits to the CAN_ACR register.
• MTCR: Mailbox Transfer Command
This flag clears the MRDY and MABT flags in the CAN_MSRx register.
When several mailboxes are requested to be transmitted simultaneously, they are transmitted in turn. The mailbox with the
highest priority is serviced first. If several mailboxes have the same priority, the mailbox with the lowest number is serviced
first (i.e., MBx0 will be serviced before MBx 15 if they have the same priority).
It is possible to set MTCR for several mailboxes at the same time by writing to the CAN_TCR register.
Mailbox Object Type Description
Receive No action
Receive with overwrite No action
Transmit Cancels transfer request if the message has not been transmitted to the
CAN transceiver.
Consumer Cancels the current transfer before the remote frame has been sent.
Producer Cancels the current transfer. The next remote frame will not be serviced.
Mailbox Object Type Description
Receive Allows the reception of the next message.
Receive with overwrite Triggers a new reception.
Transmit Sends data prepared in the mailbox as soon as possible.
Consumer Sends a remote transmission frame.
Producer Sends data prepared in the mailbox after receiving a remote frame from a
Consumer.
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41. Ethernet MAC 10/100 (EMAC)
41.1 Description
The EMAC module implements a 10/100 Ethernet MAC compatible with the IEEE 802.3 standard using an
address checker, statistics and control registers, receive and transmit blocks, and a DMA interface.
The address checker recognizes four specific 48-bit addresses and contains a 64-bit hash register for matching
multicast and unicast addresses. It can recognize the broadcast address of all ones, copy all frames, and act on an
external address match signal.
41.2 Embedded Characteristics
EMAC0 supports MII interface to the physical layer, EMAC1 supports RMII interface to the physical layer
Compatible with IEEE Standard 802.3
10 and 100 Mbit/s Operation
Full- and Half-duplex Operation
Statistics Counter Registers
Interrupt Generation to Signal Receive and Transmit Completion
DMA Master on Receive and Transmit Channels
Transmit and Receive FIFOs
Automatic Pad and CRC Generation on Transmitted Frames
Automatic Discard of Frames Received with Errors
Address Checking Logic Supports Up to Four Specific 48-bit Addresses
Supports Promiscuous Mode Where All Valid Received Frames are Copied to Memory
Hash Matching of Unicast and Multicast Destination Addresses
Physical Layer Management through MDIO Interface
Half-duplex Flow Control by Forcing Collisions on Incoming Frames
Full-duplex Flow Control with Recognition of Incoming Pause Frames
Support for 802.1Q VLAN Tagging with Recognition of Incoming VLAN and Priority Tagged Frames
Multiple Buffers per Receive and Transmit Frame
Jumbo Frames Up to 10240 bytes Supported
The statistics register block contains registers for counting various types of event associated with transmit and
receive operations. These registers, along with the status words stored in the receive buffer list, enable software to
generate network management statistics compatible with IEEE 802.3.
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41.3 Block Diagram
Figure 41-1. EMAC Block Diagram
APB
Slave Register Interface
DMA Interface
Address Checker
Statistics Registers
Control Registers
Ethernet Receive
Ethernet Transmit
MDIO
MII/RMII
RX FIFO TX FIFO
AHB
Master
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41.4 Functional Description
The MACB has several clock domains:
System bus clock (AHB and APB): DMA and register blocks
Transmit clock: transmit block
Receive clock: receive and address checker block
The system bus clock must run at least as fast as the receive clock and transmit clock (25 MHz at 100 Mbps, and
2.5 MHZ at 10 Mbps).
Figure 41-1 illustrates the different blocks of the EMAC module.
The control registers drive the MDIO interface, setup up DMA activity, start frame transmission and select modes
of operation such as full- or half-duplex.
The receive block checks for valid preamble, FCS, alignment and length, and presents received frames to the
address checking block and DMA interface.
The transmit block takes data from the DMA interface, adds preamble and, if necessary, pad and FCS, and
transmits data according to the CSMA/CD (carrier sense multiple access with collision detect) protocol. The start
of transmission is deferred if CRS (carrier sense) is active.
If COL (collision) becomes active during transmission, a jam sequence is asserted and the transmission is retried
after a random back off. CRS and COL have no effect in full duplex mode.
The DMA block connects to external memory through its AHB bus interface. It contains receive and transmit FIFOs
for buffering frame data. It loads the transmit FIFO and empties the receive FIFO using AHB bus master
operations. Receive data is not sent to memory until the address checking logic has determined that the frame
should be copied. Receive or transmit frames are stored in one or more buffers. Receive buffers have a fixed
length of 128 bytes. Transmit buffers range in length between 0 and 2047 bytes, and up to 128 buffers are
permitted per frame. The DMA block manages the transmit and receive framebuffer queues. These queues can
hold multiple frames.
41.4.1 Clock
Synchronization module in the EMAC requires that the bus clock (hclk) runs at the speed of the macb_tx/rx_clk at
least, which is 25 MHz at 100 Mbps, and 2.5 MHz at 10 Mbps.
41.4.2 Memory Interface
Frame data is transferred to and from the EMAC through the DMA interface. All transfers are 32-bit words and may
be single accesses or bursts of 2, 3 or 4 words. Burst accesses do not cross sixteen-byte boundaries. Bursts of 4
words are the default data transfer; single accesses or bursts of less than four words may be used to transfer data
at the beginning or the end of a buffer.
The DMA controller performs six types of operation on the bus. In order of priority, these are:
1. Receive buffer manager write
2. Receive buffer manager read
3. Transmit data DMA read
4. Receive data DMA write
5. Transmit buffer manager read
6. Transmit buffer manager write
41.4.2.1 FIFO
The FIFO depths are 128 bytes for receive and 128 bytes for transmit and are a function of the system clock
speed, memory latency and network speed.
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Data is typically transferred into and out of the FIFOs in bursts of four words. For receive, a bus request is asserted
when the FIFO contains four words and has space for 28 more. For transmit, a bus request is generated when
there is space for four words, or when there is space for 27 words if the next transfer is to be only one or two
words.
Thus the bus latency must be less than the time it takes to load the FIFO and transmit or receive three words (112
bytes) of data.
At 100 Mbit/s, it takes 8960 ns to transmit or receive 112 bytes of data. In addition, six master clock cycles should
be allowed for data to be loaded from the bus and to propagate through the FIFOs. For a 133 MHz master clock
this takes 45 ns, making the bus latency requirement 8915 ns.
41.4.2.2 Receive Buffers
Received frames, including CRC/FCS optionally, are written to receive buffers stored in memory. Each receive
buffer is 128 bytes long. The start location for each receive buffer is stored in memory in a list of receive buffer
descriptors at a location pointed to by the receive buffer queue pointer register. The receive buffer start location is
a word address. For the first buffer of a frame, the start location can be offset by up to three bytes depending on
the value written to bits 14 and 15 of the network configuration register. If the start location of the buffer is offset the
available length of the first buffer of a frame is reduced by the corresponding number of bytes.
Each list entry consists of two words, the first being the address of the receive buffer and the second being the
receive status. If the length of a receive frame exceeds the buffer length, the status word for the used buffer is
written with zeroes except for the “start of frame” bit and the offset bits, if appropriate. Bit zero of the address field
is written to one to show the buffer has been used. The receive buffer manager then reads the location of the next
receive buffer and fills that with receive frame data. The final buffer descriptor status word contains the complete
frame status. Refer to Table 41-1 for details of the receive buffer descriptor list.
Table 41-1. Receive Buffer Descriptor Entry
Bit Function
Word 0
31:2 Address of beginning of buffer
1 Wrap - marks last descriptor in receive buffer descriptor list.
0
Ownership - needs to be zero for the EMAC to write data to the receive buffer. The EMAC sets this to one once it has
successfully written a frame to memory.
Software has to clear this bit before the buffer can be used again.
Word 1
31 Global all ones broadcast address detected
30 Multicast hash match
29 Unicast hash match
28 External address match
27 Reserved for future use
26 Specific address register 1 match
25 Specific address register 2 match
24 Specific address register 3 match
23 Specific address register 4 match
22 Type ID match
21 VLAN tag detected (i.e., type id of 0x8100)
20 Priority tag detected (i.e., type id of 0x8100 and null VLAN identifier)
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To receive frames, the buffer descriptors must be initialized by writing an appropriate address to bits 31 to 2 in the
first word of each list entry. Bit zero must be written with zero. Bit one is the wrap bit and indicates the last entry in
the list.
The start location of the receive buffer descriptor list must be written to the receive buffer queue pointer register
before setting the receive enable bit in the network control register to enable receive. As soon as the receive block
starts writing received frame data to the receive FIFO, the receive buffer manager reads the first receive buffer
location pointed to by the receive buffer queue pointer register.
If the filter block then indicates that the frame should be copied to memory, the receive data DMA operation starts
writing data into the receive buffer. If an error occurs, the buffer is recovered. If the current buffer pointer has its
wrap bit set or is the 1024th descriptor, the next receive buffer location is read from the beginning of the receive
descriptor list. Otherwise, the next receive buffer location is read from the next word in memory.
There is an 11-bit counter to count out the 2048 word locations of a maximum length, receive buffer descriptor list.
This is added with the value originally written to the receive buffer queue pointer register to produce a pointer into
the list. A read of the receive buffer queue pointer register returns the pointer value, which is the queue entry
currently being accessed. The counter is reset after receive status is written to a descriptor that has its wrap bit set
or rolls over to zero after 1024 descriptors have been accessed. The value written to the receive buffer pointer
register may be any word-aligned address, provided that there are at least 2048 word locations available between
the pointer and the top of the memory.
Section 3.6 of the AMBA 2.0 specification states that bursts should not cross 1K boundaries. As receive buffer
manager writes are bursts of two words, to ensure that this does not occur, it is best to write the pointer register
with the least three significant bits set to zero. As receive buffers are used, the receive buffer manager sets bit zero
of the first word of the descriptor to indicate used. If a receive error is detected the receive buffer currently being
written is recovered. Previous buffers are not recovered. Software should search through the used bits in the buffer
descriptors to find out how many frames have been received. It should be checking the start-of-frame and end-of-
frame bits, and not rely on the value returned by the receive buffer queue pointer register which changes
continuously as more buffers are used.
For CRC errored frames, excessive length frames or length field mismatched frames, all of which are counted in
the statistics registers, it is possible that a frame fragment might be stored in a sequence of receive buffers.
Software can detect this by looking for start of frame bit set in a buffer following a buffer with no end of frame bit
set.
For a properly working Ethernet system, there should be no excessively long frames or frames greater than 128
bytes with CRC/FCS errors. Collision fragments are less than 128 bytes long. Therefore, it is a rare occurrence to
find a frame fragment in a receive buffer.
19:17 VLAN priority (only valid if bit 21 is set)
16 Concatenation format indicator (CFI) bit (only valid if bit 21 is set)
15 End of frame - when set the buffer contains the end of a frame. If end of frame is not set, then the only other valid status
are bits 12, 13 and 14.
14 Start of frame - when set the buffer contains the start of a frame. If both bits 15 and 14 are set, then the buffer contains a
whole frame.
13:12
Receive buffer offset - indicates the number of bytes by which the data in the first buffer is offset from the word address.
Updated with the current values of the network configuration register. If jumbo frame mode is enabled through bit 3 of the
network configuration register, then bits 13:12 of the receive buffer descriptor entry are used to indicate bits 13:12 of the
frame length.
11:0 Length of frame including FCS (if selected). Bits 13:12 are also used if jumbo frame mode is selected.
Table 41-1. Receive Buffer Descriptor Entry (Continued)
Bit Function
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If bit zero is set when the receive buffer manager reads the location of the receive buffer, then the buffer has
already been used and cannot be used again until software has processed the frame and cleared bit zero. In this
case, the DMA block sets the buffer not available bit in the receive status register and triggers an interrupt.
If bit zero is set when the receive buffer manager reads the location of the receive buffer and a frame is being
received, the frame is discarded and the receive resource error statistics register is incremented.
A receive overrun condition occurs when bus was not granted in time or because HRESP was not OK (bus error).
In a receive overrun condition, the receive overrun interrupt is asserted and the buffer currently being written is
recovered. The next frame received with an address that is recognized reuses the buffer.
If bit 17 of the network configuration register is set, the FCS of received frames shall not be copied to memory. The
frame length indicated in the receive status field shall be reduced by four bytes in this case.
41.4.2.3 Transmit Buffer
Frames to be transmitted are stored in one or more transmit buffers. Transmit buffers can be between 0 and 2047
bytes long, so it is possible to transmit frames longer than the maximum length specified in IEEE Standard 802.3.
Zero length buffers are allowed. The maximum number of buffers permitted for each transmit frame is 128.
The start location for each transmit buffer is stored in memory in a list of transmit buffer descriptors at a location
pointed to by the transmit buffer queue pointer register. Each list entry consists of two words, the first being the
byte address of the transmit buffer and the second containing the transmit control and status. Frames can be
transmitted with or without automatic CRC generation. If CRC is automatically generated, pad is also automatically
generated to take frames to a minimum length of 64 bytes. Table 41-2 on page 1248 defines an entry in the
transmit buffer descriptor list. To transmit frames, the buffer descriptors must be initialized by writing an
appropriate byte address to bits 31 to 0 in the first word of each list entry. The second transmit buffer descriptor is
initialized with control information that indicates the length of the buffer, whether or not it is to be transmitted with
CRC and whether the buffer is the last buffer in the frame.
After transmission, the control bits are written back to the second word of the first buffer along with the “used” bit
and other status information. Bit 31 is the “used” bit which must be zero when the control word is read if
transmission is to happen. It is written to one when a frame has been transmitted. Bits 27, 28 and 29 indicate
various transmit error conditions. Bit 30 is the “wrap” bit which can be set for any buffer within a frame. If no wrap
bit is encountered after 1024 descriptors, the queue pointer rolls over to the start in a similar fashion to the receive
queue.
The transmit buffer queue pointer register must not be written while transmit is active. If a new value is written to
the transmit buffer queue pointer register, the queue pointer resets itself to point to the beginning of the new
queue. If transmit is disabled by writing to bit 3 of the network control, the transmit buffer queue pointer register
resets to point to the beginning of the transmit queue. Note that disabling receive does not have the same effect on
the receive queue pointer.
Once the transmit queue is initialized, transmit is activated by writing to bit 9, the Transmit Start bit of the network
control register. Transmit is halted when a buffer descriptor with its used bit set is read, or if a transmit error occurs,
or by writing to the transmit halt bit of the network control register. (Transmission is suspended if a pause frame is
received while the pause enable bit is set in the network configuration register.) Rewriting the start bit while
transmission is active is allowed.
Transmission control is implemented with a Tx_go variable which is readable in the transmit status register at bit
location 3. The Tx_go variable is reset when:
̶transmit is disabled
̶a buffer descriptor with its ownership bit set is read
̶a new value is written to the transmit buffer queue pointer register
̶bit 10, tx_halt, of the network control register is written
̶there is a transmit error such as too many retries or a transmit underrun.
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To set tx_go, write to bit 9, tx_start, of the network control register. Transmit halt does not take effect until any
ongoing transmit finishes. If a collision occurs during transmission of a multi-buffer frame, transmission
automatically restarts from the first buffer of the frame. If a “used” bit is read midway through transmission of a
multi-buffer frame, this is treated as a transmit error. Transmission stops, tx_er is asserted and the FCS is bad.
If transmission stops due to a transmit error, the transmit queue pointer resets to point to the beginning of the
transmit queue. Software needs to re-initialize the transmit queue after a transmit error.
If transmission stops due to a “used” bit being read at the start of the frame, the transmission queue pointer is not
reset and transmit starts from the same transmit buffer descriptor when the transmit start bit is written
41.4.3 Transmit Block
This block transmits frames in accordance with the Ethernet IEEE 802.3 CSMA/CD protocol. Frame assembly
starts by adding preamble and the start frame delimiter. Data is taken from the transmit FIFO a word at a time.
Data is transmitted least significant nibble first. If necessary, padding is added to increase the frame length to 60
bytes. CRC is calculated as a 32-bit polynomial. This is inverted and appended to the end of the frame, taking the
frame length to a minimum of 64 bytes. If the No CRC bit is set in the second word of the last buffer descriptor of a
transmit frame, neither pad nor CRC are appended.
In full-duplex mode, frames are transmitted immediately. Back-to-back frames are transmitted at least 96 bit times
apart to guarantee the interframe gap.
In half-duplex mode, the transmitter checks carrier sense. If asserted, it waits for it to de-assert and then starts
transmission after the interframe gap of 96 bit times. If the collision signal is asserted during transmission, the
transmitter transmits a jam sequence of 32 bits taken from the data register and then retry transmission after the
back off time has elapsed.
The back-off time is based on an XOR of the 10 least significant bits of the data coming from the transmit FIFO and
a 10-bit pseudo random number generator. The number of bits used depends on the number of collisions seen.
Table 41-2. Transmit Buffer Descriptor Entry
Bit Function
Word 0
31:0 Byte Address of buffer
Word 1
31
Used. Needs to be zero for the EMAC to read data from the transmit buffer. The EMAC sets this to one for the first buffer
of a frame once it has been successfully transmitted.
Software has to clear this bit before the buffer can be used again.
Note: This bit is only set for the first buffer in a frame unlike receive where all buffers have the Used bit set once
used.
30 Wrap. Marks last descriptor in transmit buffer descriptor list.
29 Retry limit exceeded, transmit error detected
28 Transmit underrun, occurs either when hresp is not OK (bus error) or the transmit data could not be fetched in time or
when buffers are exhausted in mid frame.
27 Buffers exhausted in mid frame
26:17 Reserved
16 No CRC. When set, no CRC is appended to the current frame. This bit only needs to be set for the last buffer of a frame.
15 Last buffer. When set, this bit indicates the last buffer in the current frame has been reached.
14:11 Reserved
10:0 Length of buffer
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After the first collision, 1 bit is used, after the second 2, and so on up to 10. Above 10, all 10 bits are used. An error
is indicated and no further attempts are made if 16 attempts cause collisions.
If transmit DMA underruns, bad CRC is automatically appended using the same mechanism as jam insertion and
the tx_er signal is asserted. For a properly configured system, this should never happen.
If the back pressure bit is set in the network control register in half duplex mode, the transmit block transmits 64
bits of data, which can consist of 16 nibbles of 1011 or in bit-rate mode 64 1s, whenever it sees an incoming frame
to force a collision. This provides a way of implementing flow control in half-duplex mode.
41.4.4 Pause Frame Support
The start of an 802.3 pause frame is as follows:
The network configuration register contains a receive pause enable bit (13). If a valid pause frame is received, the
pause time register is updated with the frame’s pause time, regardless of its current contents and regardless of the
state of the configuration register bit 13. An interrupt (12) is triggered when a pause frame is received, assuming it
is enabled in the interrupt mask register. If bit 13 is set in the network configuration register and the value of the
pause time register is non-zero, no new frame is transmitted until the pause time register has decremented to zero.
The loading of a new pause time, and hence the pausing of transmission, only occurs when the EMAC is
configured for full-duplex operation. If the EMAC is configured for half-duplex, there is no transmission pause, but
the pause frame received interrupt is still triggered.
A valid pause frame is defined as having a destination address that matches either the address stored in specific
address register 1 or matches 0x0180C2000001 and has the MAC control frame type ID of 0x8808 and the pause
opcode of 0x0001. Pause frames that have FCS or other errors are treated as invalid and are discarded. Valid
pause frames received increment the Pause Frame Received statistic register.
The pause time register decrements every 512 bit times (i.e., 128 rx_clks in nibble mode) once transmission
has stopped. For test purposes, the register decrements every rx_clk cycle once transmission has stopped if bit
12 (retry test) is set in the network configuration register. If the pause enable bit (13) is not set in the network
configuration register, then the decrementing occurs regardless of whether transmission has stopped or not.
An interrupt (13) is asserted whenever the pause time register decrements to zero (assuming it is enabled in the
interrupt mask register).
41.4.5 Receive Block
The receive block checks for valid preamble, FCS, alignment and length, presents received frames to the DMA
block and stores the frames destination address for use by the address checking block. If, during frame reception,
the frame is found to be too long or rx_er is asserted, a bad frame indication is sent to the DMA block. The DMA
block then ceases sending data to memory. At the end of frame reception, the receive block indicates to the DMA
block whether the frame is good or bad. The DMA block recovers the current receive buffer if the frame was bad.
The receive block signals the register block to increment the alignment error, the CRC (FCS) error, the short
frame, long frame, jabber error, the receive symbol error statistics and the length field mismatch statistics.
The enable bit for jumbo frames in the network configuration register allows the EMAC to receive jumbo frames of
up to 10240 bytes in size. This operation does not form part of the IEEE802.3 specification and is disabled by
default. When jumbo frames are enabled, frames received with a frame size greater than 10240 bytes are
discarded.
Table 41-3. Start of an 802.3 Pause Frame
Destination Address Source
Address
Type
(Mac Control Frame) Pause Opcode Pause Time
0x0180C2000001 6 bytes 0x8808 0x0001 2 bytes
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41.4.6 Address Checking Block
The address checking (or filter) block indicates to the DMA block which receive frames should be copied to
memory. Whether a frame is copied depends on what is enabled in the network configuration register, the state of
the external match pin, the contents of the specific address and hash registers and the frame’s destination
address. In this implementation of the EMAC, the frame’s source address is not checked. Provided that bit 18 of
the Network Configuration register is not set, a frame is not copied to memory if the EMAC is transmitting in half
duplex mode at the time a destination address is received. If bit 18 of the Network Configuration register is set,
frames can be received while transmitting in half-duplex mode.
Ethernet frames are transmitted a byte at a time, least significant bit first. The first six bytes (48 bits) of an Ethernet
frame make up the destination address. The first bit of the destination address, the LSB of the first byte of the
frame, is the group/individual bit: this is One for multicast addresses and Zero for unicast. The All Ones address is
the broadcast address, and a special case of multicast.
The EMAC supports recognition of four specific addresses. Each specific address requires two registers, specific
address register bottom and specific address register top. Specific address register bottom stores the first four
bytes of the destination address and specific address register top contains the last two bytes. The addresses
stored can be specific, group, local or universal.
The destination address of received frames is compared against the data stored in the specific address registers
once they have been activated. The addresses are deactivated at reset or when their corresponding specific
address register bottom is written. They are activated when specific address register top is written. If a receive
frame address matches an active address, the frame is copied to memory.
The following example illustrates the use of the address match registers for a MAC address of 21:43:65:87:A9:CB.
Preamble 55
SFD D5
DA (Octet0 - LSB) 21
DA(Octet 1) 43
DA(Octet 2) 65
DA(Octet 3) 87
DA(Octet 4) A9
DA (Octet5 - MSB) CB
SA (LSB) 00
SA 00
SA 00
SA 00
SA 00
SA (MSB) 43
SA (LSB) 21
The sequence above shows the beginning of an Ethernet frame. Byte order of transmission is from top to bottom
as shown. For a successful match to specific address 1, the following address matching registers must be set up:
Base address + 0x98 0x87654321 (Bottom)
Base address + 0x9C 0x0000CBA9 (Top)
And for a successful match to the Type ID register, the following should be set up:
Base address + 0xB8 0x00004321
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41.4.7 Broadcast Address
The broadcast address of 0xFFFFFFFFFFFF is recognized if the ‘no broadcast’ bit in the network configuration
register is zero.
41.4.8 Hash Addressing
The hash address register is 64 bits long and takes up two locations in the memory map. The least significant bits
are stored in hash register bottom and the most significant bits in hash register top.
The unicast hash enable and the multicast hash enable bits in the network configuration register enable the
reception of hash matched frames. The destination address is reduced to a 6-bit index into the 64-bit hash register
using the following hash function. The hash function is an exclusive or of every sixth bit of the destination address.
hash_index[5] = da[5] ^ da[11] ^ da[17] ^ da[23] ^ da[29] ^ da[35] ^ da[41] ^ da[47]
hash_index[4] = da[4] ^ da[10] ^ da[16] ^ da[22] ^ da[28] ^ da[34] ^ da[40] ^ da[46]
hash_index[3] = da[3] ^ da[09] ^ da[15] ^ da[21] ^ da[27] ^ da[33] ^ da[39] ^ da[45]
hash_index[2] = da[2] ^ da[08] ^ da[14] ^ da[20] ^ da[26] ^ da[32] ^ da[38] ^ da[44]
hash_index[1] = da[1] ^ da[07] ^ da[13] ^ da[19] ^ da[25] ^ da[31] ^ da[37] ^ da[43]
hash_index[0] = da[0] ^ da[06] ^ da[12] ^ da[18] ^ da[24] ^ da[30] ^ da[36] ^ da[42]
da[0] represents the least significant bit of the first byte received, that is, the multicast/unicast indicator, and
da[47] represents the most significant bit of the last byte received.
If the hash index points to a bit that is set in the hash register, then the frame is matched according to whether the
frame is multicast or unicast.
A multicast match is signalled if the multicast hash enable bit is set. da[0] is 1 and the hash index points to a bit set
in the hash register.
A unicast match is signalled if the unicast hash enable bit is set. da[0] is 0 and the hash index points to a bit set in
the hash register.
To receive all multicast frames, the hash register should be set with all ones and the multicast hash enable bit
should be set in the network configuration register.
41.4.9 Copy All Frames (or Promiscuous Mode)
If the copy all frames bit is set in the network configuration register, then all non-errored frames are copied to
memory. For example, frames that are too long, too short, or have FCS errors or rx_er asserted during reception
are discarded and all others are received. Frames with FCS errors are copied to memory if bit 19 in the network
configuration register is set.
41.4.10 Type ID Checking
The contents of the type_id register are compared against the length/type ID of received frames (i.e., bytes 13 and
14). Bit 22 in the receive buffer descriptor status is set if there is a match. The reset state of this register is zero
which is unlikely to match the length/type ID of any valid Ethernet frame.
Note: A type ID match does not affect whether a frame is copied to memory.
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41.4.11 VLAN Support
An Ethernet encoded 802.1Q VLAN tag looks like this:
The VLAN tag is inserted at the 13th byte of the frame, adding an extra four bytes to the frame. If the VID (VLAN
identifier) is null (0x000), this indicates a priority-tagged frame. The MAC can support frame lengths up to 1536
bytes, 18 bytes more than the original Ethernet maximum frame length of 1518 bytes. This is achieved by setting
bit 8 in the network configuration register.
The following bits in the receive buffer descriptor status word give information about VLAN tagged frames:
Bit 21 set if receive frame is VLAN tagged (i.e. type id of 0x8100)
Bit 20 set if receive frame is priority tagged (i.e. type id of 0x8100 and null VID). (If bit 20 is set bit 21 is set
also.)
Bit 19, 18 and 17 set to priority if bit 21 is set
Bit 16 set to CFI if bit 21 is set
41.4.12 PHY Maintenance
The register EMAC_MAN enables the EMAC to communicate with a PHY by means of the MDIO interface. It is
used during auto-negotiation to ensure that the EMAC and the PHY are configured for the same speed and duplex
configuration.
The PHY maintenance register is implemented as a shift register. Writing to the register starts a shift operation
which is signalled as complete when bit two is set in the network status register (about 2000 MCK cycles later
when bit ten is set to zero, and bit eleven is set to one in the network configuration register). An interrupt is
generated as this bit is set. During this time, the MSB of the register is output on the MDIO pin and the LSB
updated from the MDIO pin with each MDC cycle. This causes transmission of a PHY management frame on
MDIO.
Reading during the shift operation returns the current contents of the shift register. At the end of management
operation, the bits have shifted back to their original locations. For a read operation, the data bits are updated with
data read from the PHY. It is important to write the correct values to the register to ensure a valid PHY
management frame is produced.
The MDIO interface can read IEEE 802.3 clause 45 PHYs as well as clause 22 PHYs. To read clause 45 PHYs,
bits[31:28] should be written as 0x0011. For a description of MDC generation, see the network configuration
register in the “Network Control Register” on page 1259.
41.4.13 Physical Interface
Depending on products, the Ethernet MAC is capable of interfacing to RMII or MII Interface. The RMII bit in the
EMAC_USRIO register controls the interface that is selected. When this bit is set, the RMII interface is selected,
else the MII interface is selected.
The MII and RMII interfaces are capable of both 10 Mb/s and 100 Mb/s data rates as described in the IEEE 802.3u
standard. The signals used by the MII and RMII interfaces are described in Table 41-5.
Table 41-4. 802.1Q VLAN Tag
TPID (Tag Protocol Identifier) 16 bits TCI (Tag Control Information) 16 bits
0x8100 First 3 bits priority, then CFI bit, last 12 bits VID
Table 41-5. Pin Configuration, Depending on Products
Pin Name MII RMII
ETXCK_EREFCK ETXCK: Transmit Clock EREFCK: Reference Clock
ECRS ECRS: Carrier Sense
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The intent of the RMII is to provide a reduced pin count alternative to the IEEE 802.3u MII. It uses 2 bits for
transmit (ETX0 and ETX1) and two bits for receive (ERX0 and ERX1). There is a Transmit Enable (ETXEN), a
Receive Error (ERXER), a Carrier Sense (ECRS_DV), and a 50 MHz Reference Clock (ETXCK_EREFCK) for
100Mb/s data rate.
41.4.13.1RMII Transmit and Receive Operation
The same signals are used internally for both the RMII and the MII operations. The RMII maps these signals in a
more pin-efficient manner. The transmit and receive bits are converted from a 4-bit parallel format to a 2-bit parallel
scheme that is clocked at twice the rate. The carrier sense and data valid signals are combined into the ECRSDV
signal. This signal contains information on carrier sense, FIFO status, and validity of the data. Transmit error bit
(ETXER) and collision detect (ECOL) are not used in RMII mode.
ECOL ECOL: Collision Detect
ERXDV ERXDV: Data Valid ECRSDV: Carrier Sense/Data Valid
ERX0 - ERX3 ERX0 - ERX3: 4-bit Receive Data ERX0 - ERX1: 2-bit Receive Data
ERXER ERXER: Receive Error ERXER: Receive Error
ERXCK ERXCK: Receive Clock
ETXEN ETXEN: Transmit Enable ETXEN: Transmit Enable
ETX0-ETX3 ETX0 - ETX3: 4-bit Transmit Data ETX0 - ETX1: 2-bit Transmit Data
ETXER ETXER: Transmit Error
Table 41-5. Pin Configuration, Depending on Products
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41.5 Programming Interface
41.5.1 Initialization
41.5.1.1 Configuration
Initialization of the EMAC configuration (e.g., loop-back mode, frequency ratios) must be done while the transmit
and receive circuits are disabled. See the description of the network control register and network configuration
register earlier in this document.
To change loop-back mode, the following sequence of operations must be followed:
1. Write to network control register to disable transmit and receive circuits.
2. Write to network control register to change loop-back mode.
3. Write to network control register to re-enable transmit or receive circuits.
Note: These writes to network control register cannot be combined in any way.
41.5.1.2 Receive Buffer List
Receive data is written to areas of data (i.e., buffers) in system memory. These buffers are listed in another data
structure that also resides in main memory. This data structure (receive buffer queue) is a sequence of descriptor
entries as defined in “Receive Buffer Descriptor Entry” on page 1245. It points to this data structure.
Figure 41-2. Receive Buffer List
To create the list of buffers:
1. Allocate a number (n) of buffers of 128 bytes in system memory.
2. Allocate an area 2n words for the receive buffer descriptor entry in system memory and create n entries in
this list. Mark all entries in this list as owned by EMAC, i.e., bit 0 of word 0 set to 0.
3. If less than 1024 buffers are defined, the last descriptor must be marked with the wrap bit (bit 1 in word 0 set
to 1).
4. Write address of receive buffer descriptor entry to EMAC register receive_buffer queue pointer.
5. The receive circuits can then be enabled by writing to the address recognition registers and then to the
network control register.
Receive Buffer Queue Pointer
(MAC Register)
Receive Buffer 0
Receive Buffer 1
Receive Buffer N
Receive Buffer Descriptor List
(In memory)
(In memory)
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41.5.1.3 Transmit Buffer List
Transmit data is read from areas of data (the buffers) in system memory These buffers are listed in another data
structure that also resides in main memory. This data structure (Transmit Buffer Queue) is a sequence of
descriptor entries (as defined in Table 41-2 on page 1248) that points to this data structure.
To create this list of buffers:
1. Allocate a number (n) of buffers of between 1 and 2047 bytes of data to be transmitted in system memory.
Up to 128 buffers per frame are allowed.
2. Allocate an area 2n words for the transmit buffer descriptor entry in system memory and create N entries in
this list. Mark all entries in this list as owned by EMAC, i.e. bit 31 of word 1 set to 0.
3. If fewer than 1024 buffers are defined, the last descriptor must be marked with the wrap bit — bit 30 in word
1 set to 1.
4. Write address of transmit buffer descriptor entry to EMAC register transmit_buffer queue pointer.
5. The transmit circuits can then be enabled by writing to the network control register.
41.5.1.4 Address Matching
The EMAC register-pair hash address and the four specific address register-pairs must be written with the required
values. Each register-pair comprises a bottom register and top register, with the bottom register being written first.
The address matching is disabled for a particular register-pair after the bottom-register has been written and re-
enabled when the top register is written. See “Address Checking Block” on page 1250. for details of address
matching. Each register-pair may be written at any time, regardless of whether the receive circuits are enabled or
disabled.
41.5.1.5 Interrupts
There are 14 interrupt conditions that are detected within the EMAC. These are ORed to make a single interrupt.
Depending on the overall system design, this may be passed through a further level of interrupt collection (interrupt
controller). On receipt of the interrupt signal, the CPU enters the interrupt handler (Refer to the Interrupt
Controller). To ascertain which interrupt has been generated, read the interrupt status register. Note that this
register clears itself when read. At reset, all interrupts are disabled. To enable an interrupt, write to interrupt enable
register with the pertinent interrupt bit set to 1. To disable an interrupt, write to interrupt disable register with the
pertinent interrupt bit set to 1. To check whether an interrupt is enabled or disabled, read interrupt mask register: if
the bit is set to 1, the interrupt is disabled.
41.5.1.6 Transmitting Frames
To set up a frame for transmission:
1. Enable transmit in the network control register.
2. Allocate an area of system memory for transmit data. This does not have to be contiguous, varying byte
lengths can be used as long as they conclude on byte borders.
3. Set-up the transmit buffer list.
4. Set the network control register to enable transmission and enable interrupts.
5. Write data for transmission into these buffers.
6. Write the address to transmit buffer descriptor queue pointer.
7. Write control and length to word one of the transmit buffer descriptor entry.
8. Write to the transmit start bit in the network control register.
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41.5.1.7 Receiving Frames
When a frame is received and the receive circuits are enabled, the EMAC checks the address and, in the following
cases, the frame is written to system memory:
if it matches one of the four specific address registers.
if it matches the hash address function.
if it is a broadcast address (0xFFFFFFFFFFFF) and broadcasts are allowed.
if the EMAC is configured to copy all frames.
The register receive buffer queue pointer points to the next entry (see Table 41-1 on page 1245) and the EMAC
uses this as the address in system memory to write the frame to. Once the frame has been completely and
successfully received and written to system memory, the EMAC then updates the receive buffer descriptor entry
with the reason for the address match and marks the area as being owned by software. Once this is complete an
interrupt receive complete is set. Software is then responsible for handling the data in the buffer and then releasing
the buffer by writing the ownership bit back to 0.
If the EMAC is unable to write the data at a rate to match the incoming frame, then an interrupt receive overrun is
set. If there is no receive buffer available, i.e., the next buffer is still owned by software, the interrupt receive buffer
not available is set. If the frame is not successfully received, a statistic register is incremented and the frame is
discarded without informing software.
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41.6 Ethernet MAC 10/100 (EMAC) User Interface
Table 41-6. Register Mapping
Offset Register Name Access Reset
0x00 Network Control Register EMAC_NCR Read-write 0
0x04 Network Configuration Register EMAC_NCFGR Read-write 0x800
0x08 Network Status Register EMAC_NSR Read-only -
0x0C Reserved
0x10 Reserved
0x14 Transmit Status Register EMAC_TSR Read-write 0x0000_0000
0x18 Receive Buffer Queue Pointer Register EMAC_RBQP Read-write 0x0000_0000
0x1C Transmit Buffer Queue Pointer Register EMAC_TBQP Read-write 0x0000_0000
0x20 Receive Status Register EMAC_RSR Read-write 0x0000_0000
0x24 Interrupt Status Register EMAC_ISR Read-write 0x0000_0000
0x28 Interrupt Enable Register EMAC_IER Write-only -
0x2C Interrupt Disable Register EMAC_IDR Write-only -
0x30 Interrupt Mask Register EMAC_IMR Read-only 0x0000_3FFF
0x34 Phy Maintenance Register EMAC_MAN Read-write 0x0000_0000
0x38 Pause Time Register EMAC_PTR Read-write 0x0000_0000
0x3C Pause Frames Received Register EMAC_PFR Read-write 0x0000_0000
0x40 Frames Transmitted Ok Register EMAC_FTO Read-write 0x0000_0000
0x44 Single Collision Frames Register EMAC_SCF Read-write 0x0000_0000
0x48 Multiple Collision Frames Register EMAC_MCF Read-write 0x0000_0000
0x4C Frames Received Ok Register EMAC_FRO Read-write 0x0000_0000
0x50 Frame Check Sequence Errors Register EMAC_FCSE Read-write 0x0000_0000
0x54 Alignment Errors Register EMAC_ALE Read-write 0x0000_0000
0x58 Deferred Transmission Frames Register EMAC_DTF Read-write 0x0000_0000
0x5C Late Collisions Register EMAC_LCOL Read-write 0x0000_0000
0x60 Excessive Collisions Register EMAC_ECOL Read-write 0x0000_0000
0x64 Transmit Underrun Errors Register EMAC_TUND Read-write 0x0000_0000
0x68 Carrier Sense Errors Register EMAC_CSE Read-write 0x0000_0000
0x6C Receive Resource Errors Register EMAC_RRE Read-write 0x0000_0000
0x70 Receive Overrun Errors Register EMAC_ROV Read-write 0x0000_0000
0x74 Receive Symbol Errors Register EMAC_RSE Read-write 0x0000_0000
0x78 Excessive Length Errors Register EMAC_ELE Read-write 0x0000_0000
0x7C Receive Jabbers Register EMAC_RJA Read-write 0x0000_0000
0x80 Undersize Frames Register EMAC_USF Read-write 0x0000_0000
0x84 SQE Test Errors Register EMAC_STE Read-write 0x0000_0000
0x88 Received Length Field Mismatch Register EMAC_RLE Read-write 0x0000_0000
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0x90 Hash Register Bottom [31:0] Register EMAC_HRB Read-write 0x0000_0000
0x94 Hash Register Top [63:32] Register EMAC_HRT Read-write 0x0000_0000
0x98 Specific Address 1 Bottom Register EMAC_SA1B Read-write 0x0000_0000
0x9C Specific Address 1 Top Register EMAC_SA1T Read-write 0x0000_0000
0xA0 Specific Address 2 Bottom Register EMAC_SA2B Read-write 0x0000_0000
0xA4 Specific Address 2 Top Register EMAC_SA2T Read-write 0x0000_0000
0xA8 Specific Address 3 Bottom Register EMAC_SA3B Read-write 0x0000_0000
0xAC Specific Address 3 Top Register EMAC_SA3T Read-write 0x0000_0000
0xB0 Specific Address 4 Bottom Register EMAC_SA4B Read-write 0x0000_0000
0xB4 Specific Address 4 Top Register EMAC_SA4T Read-write 0x0000_0000
0xB8 Type ID Checking Register EMAC_TID Read-write 0x0000_0000
0xC0 User Input/Output Register EMAC_USRIO Read-write 0x0000_0000
0xC8 - 0xFC Reserved – – –
Table 41-6. Register Mapping (Continued)
Offset Register Name Access Reset
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41.6.1 Network Control Register
Name: EMAC_NCR
Address: 0x400B0000
Access: Read-write
• LB: LoopBack
Asserts the loopback signal to the PHY.
• LLB: Loopback local
Connects txd to rxd, tx_en to rx_dv, forces full duplex and drives rx_clk and tx_clk with pclk divided by 4.
rx_clk and tx_clk may glitch as the EMAC is switched into and out of internal loop back. It is important that receive
and transmit circuits have already been disabled when making the switch into and out of internal loop back.
• RE: Receive enable
When set, enables the EMAC to receive data. When reset, frame reception stops immediately and the receive FIFO is
cleared. The receive queue pointer register is unaffected.
• TE: Transmit enable
When set, enables the Ethernet transmitter to send data. When reset transmission, stops immediately, the transmit FIFO
and control registers are cleared and the transmit queue pointer register resets to point to the start of the transmit descrip-
tor list.
• MPE: Management port enable
Set to one to enable the management port. When zero, forces MDIO to high impedance state and MDC low.
• CLRSTAT: Clear statistics registers
This bit is write only. Writing a one clears the statistics registers.
• INCSTAT: Increment statistics registers
This bit is write only. Writing a one increments all the statistics registers by one for test purposes.
• WESTAT: Write enable for statistics registers
Setting this bit to one makes the statistics registers writable for functional test purposes.
• BP: Back pressure
If set in half duplex mode, forces collisions on all received frames.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––THALTTSTARTBP
76543210
WESTAT INCSTAT CLRSTAT MPE TE RE LLB LB
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• TSTART: Start transmission
Writing one to this bit starts transmission.
• THALT: Transmit halt
Writing one to this bit halts transmission as soon as any ongoing frame transmission ends.
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41.6.2 Network Configuration Register
Name: EMAC_NCFGR
Address: 0x400B0004
Access: Read-write
• SPD: Speed
Set to 1 to indicate 100 Mbit/s operation, 0 for 10 Mbit/s. The value of this pin is reflected on the speed pin.
• FD: Full Duplex
If set to 1, the transmit block ignores the state of collision and carrier sense and allows receive while transmitting. Also con-
trols the half_duplex pin.
• CAF: Copy All Frames
When set to 1, all valid frames are received.
• JFRAME: Jumbo Frames
Set to one to enable jumbo frames of up to 10240 bytes to be accepted.
• NBC: No Broadcast
When set to 1, frames addressed to the broadcast address of all ones are not received.
• MTI: Multicast Hash Enable
When set, multicast frames are received when the 6-bit hash function of the destination address points to a bit that is set in
the hash register.
• UNI: Unicast Hash Enable
When set, unicast frames are received when the 6-bit hash function of the destination address points to a bit that is set in
the hash register.
• BIG: Receive 1536 bytes frames
Setting this bit means the EMAC receives frames up to 1536 bytes in length. Normally, the EMAC would reject any frame
above 1518 bytes.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––IRXFCSEFRHDDRFCSRLCE
15 14 13 12 11 10 9 8
RBOF PAE RTY CLK – BIG
76543210
UNI MTI NBC CAF JFRAME – FD SPD
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• CLK: MDC clock divider
Set according to system clock speed. This determines by what number system clock is divided to generate MDC. For con-
formance with 802.3, MDC must not exceed 2.5MHz (MDC is only active during MDIO read and write operations).
• RTY: Retry test
Must be set to zero for normal operation. If set to one, the back off between collisions is always one slot time. Setting this
bit to one helps testing the too many retries condition. Also used in the pause frame tests to reduce the pause counters
decrement time from 512 bit times, to every rx_clk cycle.
• PAE: Pause Enable
When set, transmission pauses when a valid pause frame is received.
• RBOF: Receive Buffer Offset
Indicates the number of bytes by which the received data is offset from the start of the first receive buffer.
• RLCE: Receive Length field Checking Enable
When set, frames with measured lengths shorter than their length fields are discarded. Frames containing a type ID in
bytes 13 and 14 — length/type ID = 0600 — are not be counted as length errors.
• DRFCS: Discard Receive FCS
When set, the FCS field of received frames are not be copied to memory.
•EFRHD:
Enable Frames to be received in half-duplex mode while transmitting.
• IRXFCS: Ignore RX FCS
When set, frames with FCS/CRC errors are not rejected and no FCS error statistics are counted. For normal operation, this
bit must be set to 0.
Value Name Description
0 HCLK_8MCK divided by 8 (MCK up to 20 MHz).
1 HCLK_16 MCK divided by 16 (MCK up to 40 MHz).
2 HCLK_32MCK divided by 32 (MCK up to 80 MHz).
3HCLK_64 MCK divided by 64 (MCK up to 160 MHz).
Value Name Description
0OFFSET_0 No offset from start of receive buffer.
1OFFSET_1 One-byte offset from start of receive buffer.
2OFFSET_2 Two-byte offset from start of receive buffer.
3OFFSET_3Three-byte offset from start of receive buffer.
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41.6.3 Network Status Register
Name: EMAC_NSR
Address: 0x400B0008
Access: Read-only
•MDIO
Returns status of the mdio_in pin. Use the PHY maintenance register for reading managed frames rather than this bit.
•IDLE
0: The PHY logic is running.
1: The PHY management logic is idle (i.e., has completed).
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––IDLEMDIO–
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41.6.4 Transmit Status Register
Name: EMAC_TSR
Address: 0x400B0014
Access: Read-write
This register, when read, provides details of the status of a transmit. Once read, individual bits may be cleared by writing 1
to them. It is not possible to set a bit to 1 by writing to the register.
• UBR: Used Bit Read
Set when a transmit buffer descriptor is read with its used bit set. Cleared by writing a one to this bit.
• COL: Collision Occurred
Set by the assertion of collision. Cleared by writing a one to this bit.
• RLES: Retry Limit exceeded
Cleared by writing a one to this bit.
• TGO: Transmit Go
If high transmit is active.
•BEX: Buffers exhausted mid frame
If the buffers run out during transmission of a frame, then transmission stops, FCS shall be bad and tx_er asserted.
Cleared by writing a one to this bit.
• COMP: Transmit Complete
Set when a frame has been transmitted. Cleared by writing a one to this bit.
• UND: Transmit Underrun
Set when transmit DMA was not able to read data from memory, either because the bus was not granted in time, because
a not OK hresp(bus error) was returned or because a used bit was read midway through frame transmission. If this
occurs, the transmitter forces bad CRC. Cleared by writing a one to this bit.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– UND COMP BEX TGO RLES COL UBR
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41.6.5 Receive Buffer Queue Pointer Register
Name: EMAC_RBQP
Address: 0x400B0018
Access: Read-write
This register points to the entry in the receive buffer queue (descriptor list) currently being used. It is written with the start
location of the receive buffer descriptor list. The lower order bits increment as buffers are used up and wrap to their original
values after either 1024 buffers or when the wrap bit of the entry is set.
Reading this register returns the location of the descriptor currently being accessed. This value increments as buffers are
used. Software should not use this register for determining where to remove received frames from the queue as it con-
stantly changes as new frames are received. Software should instead work its way through the buffer descriptor queue
checking the used bits.
Receive buffer writes also comprise bursts of two words and, as with transmit buffer reads, it is recommended that bit 2 is
always written with zero to prevent a burst crossing a 1K boundary, in violation of section 3.6 of the AMBA specification.
• ADDR: Receive buffer queue pointer address
Written with the address of the start of the receive queue, reads as a pointer to the current buffer being used.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR – –
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41.6.6 Transmit Buffer Queue Pointer Register
Name: EMAC_TBQP
Address: 0x400B001C
Access: Read-write
This register points to the entry in the transmit buffer queue (descriptor list) currently being used. It is written with the start
location of the transmit buffer descriptor list. The lower order bits increment as buffers are used up and wrap to their origi-
nal values after either 1024 buffers or when the wrap bit of the entry is set. This register can only be written when bit 3 in
the transmit status register is low.
As transmit buffer reads consist of bursts of two words, it is recommended that bit 2 is always written with zero to prevent a
burst crossing a 1K boundary, in violation of section 3.6 of the AMBA specification.
• ADDR: Transmit buffer queue pointer address
Written with the address of the start of the transmit queue, reads as a pointer to the first buffer of the frame being transmit-
ted or about to be transmitted.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR – –
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41.6.7 Receive Status Register
Name: EMAC_RSR
Address: 0x400B0020
Access: Read-write
This register, when read, provides details of the status of a receive. Once read, individual bits may be cleared by writing 1
to them. It is not possible to set a bit to 1 by writing to the register.
• BNA: Buffer Not Available
An attempt was made to get a new buffer and the pointer indicated that it was owned by the processor. The DMA rereads
the pointer each time a new frame starts until a valid pointer is found. This bit is set at each attempt that fails even if it has
not had a successful pointer read since it has been cleared.
Cleared by writing a one to this bit.
• REC: Frame Received
One or more frames have been received and placed in memory. Cleared by writing a one to this bit.
• OVR: Receive Overrun
The DMA block was unable to store the receive frame to memory, either because the bus was not granted in time or
because a not OK hresp(bus error) was returned. The buffer is recovered if this happens.
Cleared by writing a one to this bit.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––OVRRECBNA
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41.6.8 Interrupt Status Register
Name: EMAC_ISR
Address: 0x400B0024
Access: Read-write
• MFD: Management Frame Done
The PHY maintenance register has completed its operation. Cleared on read.
• RCOMP: Receive Complete
A frame has been stored in memory. Cleared on read.
• RXUBR: Receive Used Bit Read
Set when a receive buffer descriptor is read with its used bit set. Cleared on read.
• TXUBR: Transmit Used Bit Read
Set when a transmit buffer descriptor is read with its used bit set. Cleared on read.
• TUND: Ethernet Transmit Buffer Underrun
The transmit DMA did not fetch frame data in time for it to be transmitted or hresp returned not OK. Also set if a used bit
is read mid-frame or when a new transmit queue pointer is written. Cleared on read.
• RLEX: Retry Limit Exceeded
Cleared on read.
• TXERR: Transmit Error
Transmit buffers exhausted in mid-frame - transmit error. Cleared on read.
• TCOMP: Transmit Complete
Set when a frame has been transmitted. Cleared on read.
• ROVR: Receive Overrun
Set when the receive overrun status bit gets set. Cleared on read.
• HRESP: Hresp not OK
Set when the DMA block sees a bus error. Cleared on read.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – PTZ PFRE HRESP ROVR – –
76543210
TCOMP TXERR RLEX TUND TXUBR RXUBR RCOMP MFD
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• PFRE: Pause Frame Received
Indicates a valid pause has been received. Cleared on a read.
• PTZ: Pause Time Zero
Set when the pause time register, 0x38 decrements to zero. Cleared on a read.
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41.6.9 Interrupt Enable Register
Name: EMAC_IER
Address: 0x400B0028
Access: Write-only
• MFD: Management Frame sent
Enable management done interrupt.
• RCOMP: Receive Complete
Enable receive complete interrupt.
• RXUBR: Receive Used Bit Read
Enable receive used bit read interrupt.
• TXUBR: Transmit Used Bit Read
Enable transmit used bit read interrupt.
• TUND: Ethernet Transmit Buffer Underrun
Enable transmit underrun interrupt.
• RLE: Retry Limit Exceeded
Enable retry limit exceeded interrupt.
• TXERR
Enable transmit buffers exhausted in mid-frame interrupt.
• TCOMP: Transmit Complete
Enable transmit complete interrupt.
• ROVR: Receive Overrun
Enable receive overrun interrupt.
• HRESP: Hresp not OK
Enable Hresp not OK interrupt.
• PFR: Pause Frame Received
Enable pause frame received interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – PTZ PFR HRESP ROVR – –
76543210
TCOMP TXERR RLE TUND TXUBR RXUBR RCOMP MFD
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• PTZ: Pause Time Zero
Enable pause time zero interrupt.
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41.6.10 Interrupt Disable Register
Name: EMAC_IDR
Address: 0x400B002C
Access: Write-only
• MFD: Management Frame sent
Disable management done interrupt.
• RCOMP: Receive Complete
Disable receive complete interrupt.
• RXUBR: Receive Used Bit Read
Disable receive used bit read interrupt.
• TXUBR: Transmit Used Bit Read
Disable transmit used bit read interrupt.
• TUND: Ethernet Transmit Buffer Underrun
Disable transmit underrun interrupt.
• RLE: Retry Limit Exceeded
Disable retry limit exceeded interrupt.
• TXERR
Disable transmit buffers exhausted in mid-frame interrupt.
• TCOMP: Transmit Complete
Disable transmit complete interrupt.
• ROVR: Receive Overrun
Disable receive overrun interrupt.
• HRESP: Hresp not OK
Disable Hresp not OK interrupt.
• PFR: Pause Frame Received
Disable pause frame received interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – PTZ PFR HRESP ROVR – –
76543210
TCOMP TXERR RLE TUND TXUBR RXUBR RCOMP MFD
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• PTZ: Pause Time Zero
Disable pause time zero interrupt.
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41.6.11 Interrupt Mask Register
Name: EMAC_IMR
Address: 0x400B0030
Access: Read-only
• MFD: Management Frame sent
Management done interrupt masked.
• RCOMP: Receive Complete
Receive complete interrupt masked.
• RXUBR: Receive Used Bit Read
Receive used bit read interrupt masked.
• TXUBR: Transmit Used Bit Read
Transmit used bit read interrupt masked.
• TUND: Ethernet Transmit Buffer Underrun
Transmit underrun interrupt masked.
• RLE: Retry Limit Exceeded
Retry limit exceeded interrupt masked.
• TXERR
Transmit buffers exhausted in mid-frame interrupt masked.
• TCOMP: Transmit Complete
Transmit complete interrupt masked.
• ROVR: Receive Overrun
Receive overrun interrupt masked.
• HRESP: Hresp not OK
Hresp not OK interrupt masked.
• PFR: Pause Frame Received
Pause frame received interrupt masked.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – PTZ PFR HRESP ROVR – –
76543210
TCOMP TXERR RLE TUND TXUBR RXUBR RCOMP MFD
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• PTZ: Pause Time Zero
Pause time zero interrupt masked.
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41.6.12 PHY Maintenance Register
Name: EMAC_MAN
Address: 0x400B0034
Access: Read-write
•DATA
For a write operation this is written with the data to be written to the PHY.
After a read operation this contains the data read from the PHY.
•CODE:
Must be written to 10. Reads as written.
• REGA: Register Address
Specifies the register in the PHY to access.
• PHYA: PHY Address
• RW: Read-write
10 is read; 01 is write. Any other value is an invalid PHY management frame
• SOF: Start of frame
Must be written 01 for a valid frame.
31 30 29 28 27 26 25 24
SOF RW PHYA
23 22 21 20 19 18 17 16
PHYA REGA CODE
15 14 13 12 11 10 9 8
DATA
76543210
DATA
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41.6.13 Pause Time Register
Name: EMAC_PTR
Address: 0x400B0038
Access: Read-write
• PTIME: Pause Time
Stores the current value of the pause time register which is decremented every 512 bit times.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
PTIME
76543210
PTIME
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41.6.14 Hash Register Bottom
Name: EMAC_HRB
Address: 0x400B0090
Access: Read-write
• ADDR:
Bits 31:0 of the hash address register. See “Hash Addressing” on page 1251.
41.6.15 Hash Register Top
Name: EMAC_HRT
Address: 0x400B0094
Access: Read-write
• ADDR:
Bits 63:32 of the hash address register. See “Hash Addressing” on page 1251.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
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41.6.16 Specific Address 1 Bottom Register
Name: EMAC_SA1B
Address: 0x400B0098
Access: Read-write
•ADDR
Least significant bits of the destination address. Bit zero indicates whether the address is multicast or unicast and corre-
sponds to the least significant bit of the first byte received.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
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41.6.17 Specific Address 1 Top Register
Name: EMAC_SA1T
Address: 0x400B009C
Access: Read-write
•ADDR
The most significant bits of the destination address, that is bits 47 to 32.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
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41.6.18 Specific Address 2 Bottom Register
Name: EMAC_SA2B
Address: 0x400B00A0
Access: Read-write
•ADDR
Least significant bits of the destination address. Bit zero indicates whether the address is multicast or unicast and corre-
sponds to the least significant bit of the first byte received.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
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41.6.19 Specific Address 2 Top Register
Name: EMAC_SA2T
Address: 0x400B00A4
Access: Read-write
•ADDR
The most significant bits of the destination address, that is bits 47 to 32.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
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41.6.20 Specific Address 3 Bottom Register
Name: EMAC_SA3B
Address: 0x400B00A8
Access: Read-write
•ADDR
Least significant bits of the destination address. Bit zero indicates whether the address is multicast or unicast and corre-
sponds to the least significant bit of the first byte received.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
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41.6.21 Specific Address 3 Top Register
Name: EMAC_SA3T
Address: 0x400B00AC
Access: Read-write
•ADDR
The most significant bits of the destination address, that is bits 47 to 32.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
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41.6.22 Specific Address 4 Bottom Register
Name: EMAC_SA4B
Address: 0x400B00B0
Access: Read-write
•ADDR
Least significant bits of the destination address. Bit zero indicates whether the address is multicast or unicast and corre-
sponds to the least significant bit of the first byte received.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
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41.6.23 Specific Address 4 Top Register
Name: EMAC_SA4T
Address: 0x400B00B4
Access: Read-write
•ADDR
The most significant bits of the destination address, that is bits 47 to 32.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
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41.6.24 Type ID Checking Register
Name: EMAC_TID
Address: 0x400B00B8
Access: Read-write
• TID: Type ID checking
For use in comparisons with received frames TypeID/Length field.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TID
76543210
TID
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41.6.25 User Input/Output Register
Name: EMAC_USRIO
Address: 0x400B00C0
Access: Read-write
•RMII: Reduce MII
When set, this bit enables the RMII operation mode. When reset, it selects the MII mode.
• CLKEN: Clock Enable
When set, this bit enables the transceiver input clock.
Setting this bit to 0 reduces power consumption when the treasurer is not used.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––CLKENRMII
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41.6.26 EMAC Statistic Registers
These registers reset to zero on a read and stick at all ones when they count to their maximum value. They should be read
frequently enough to prevent loss of data. The receive statistics registers are only incremented when the receive enable bit
is set in the network control register. To write to these registers, bit 7 must be set in the network control register. The statis-
tics register block contains the following registers.
41.6.26.1Pause Frames Received Register
Name: EMAC_PFR
Address: 0x400B003C
Access: Read-write
• FROK: Pause Frames received OK
A 16-bit register counting the number of good pause frames received. A good frame has a length of 64 to 1518 (1536 if bit
8 set in network configuration register) and has no FCS, alignment or receive symbol errors.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
FROK
76543210
FROK
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41.6.26.2Frames Transmitted OK Register
Name: EMAC_FTO
Address: 0x400B0040
Access: Read-write
• FTOK: Frames Transmitted OK
A 24-bit register counting the number of frames successfully transmitted, i.e., no underrun and not too many retries.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FTOK
15 14 13 12 11 10 9 8
FTOK
76543210
FTOK
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41.6.26.3Single Collision Frames Register
Name: EMAC_SCF
Address: 0x400B0044
Access: Read-write
• SCF: Single Collision Frames
A 16-bit register counting the number of frames experiencing a single collision before being successfully transmitted, i.e.,
no underrun.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
SCF
76543210
SCF
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41.6.26.4Multicollision Frames Register
Name: EMAC_MCF
Address: 0x400B0048
Access: Read-write
• MCF: Multicollision Frames
A 16-bit register counting the number of frames experiencing between two and fifteen collisions prior to being successfully
transmitted, i.e., no underrun and not too many retries.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
MCF
76543210
MCF
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41.6.26.5Frames Received OK Register
Name: EMAC_FRO
Address: 0x400B004C
Access: Read-write
• FROK: Frames Received OK
A 24-bit register counting the number of good frames received, i.e., address recognized and successfully copied to mem-
ory. A good frame is of length 64 to 1518 bytes (1536 if bit 8 set in network configuration register) and has no FCS,
alignment or receive symbol errors.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FROK
15 14 13 12 11 10 9 8
FROK
76543210
FROK
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41.6.26.6Frames Check Sequence Errors Register
Name: EMAC_FCSE
Address: 0x400B0050
Access: Read-write
• FCSE: Frame Check Sequence Errors
An 8-bit register counting frames that are an integral number of bytes, have bad CRC and are between 64 and 1518 bytes
in length (1536 if bit 8 set in network configuration register). This register is also incremented if a symbol error is detected
and the frame is of valid length and has an integral number of bytes.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
FCSE
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41.6.26.7Alignment Errors Register
Name: EMAC_ALE
Address: 0x400B0054
Access: Read-write
• ALE: Alignment Errors
An 8-bit register counting frames that are not an integral number of bytes long and have bad CRC when their length is trun-
cated to an integral number of bytes and are between 64 and 1518 bytes in length (1536 if bit 8 set in network configuration
register). This register is also incremented if a symbol error is detected and the frame is of valid length and does not have
an integral number of bytes.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ALE
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41.6.26.8Deferred Transmission Frames Register
Name: EMAC_DTF
Address: 0x400B0058
Access: Read-write
• DTF: Deferred Transmission Frames
A 16-bit register counting the number of frames experiencing deferral due to carrier sense being active on their first attempt
at transmission. Frames involved in any collision are not counted nor are frames that experienced a transmit underrun.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
DTF
76543210
DTF
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41.6.26.9Late Collisions Register
Name: EMAC_LCOL
Address: 0x400B005C
Access: Read-write
• LCOL: Late Collisions
An 8-bit register counting the number of frames that experience a collision after the slot time (512 bits) has expired. A late
collision is counted twice; i.e., both as a collision and a late collision.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
LCOL
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41.6.26.10Excessive Collisions Register
Name: EMAC_ECOL
Address: 0x400B0060
Access: Read-write
• EXCOL: Excessive Collisions
An 8-bit register counting the number of frames that failed to be transmitted because they experienced 16 collisions.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
EXCOL
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41.6.26.11Transmit Underrun Errors Register
Name: EMAC_TUND
Address: 0x400B0064
Access: Read-write
• TUND: Transmit Underruns
An 8-bit register counting the number of frames not transmitted due to a transmit DMA underrun. If this register is incre-
mented, then no other statistics register is incremented.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
TUND
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41.6.26.12Carrier Sense Errors Register
Name: EMAC_CSE
Address: 0x400B0068
Access: Read-write
• CSE: Carrier Sense Errors
An 8-bit register counting the number of frames transmitted where carrier sense was not seen during transmission or
where carrier sense was deasserted after being asserted in a transmit frame without collision (no underrun). Only incre-
mented in half-duplex mode. The only effect of a carrier sense error is to increment this register. The behavior of the other
statistics registers is unaffected by the detection of a carrier sense error.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
CSE
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41.6.26.13Receive Resource Errors Register
Name: EMAC_RRE
Address: 0x400B006C
Access: Read-write
• RRE: Receive Resource Errors
A 16-bit register counting the number of frames that were address matched but could not be copied to memory because no
receive buffer was available.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
RRE
76543210
RRE
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41.6.26.14Receive Overrun Errors Register
Name: EMAC_ROV
Address: 0x400B0070
Access: Read-write
• ROVR: Receive Overrun
An 8-bit register counting the number of frames that are address recognized but were not copied to memory due to a
receive DMA overrun.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ROVR
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41.6.26.15Receive Symbol Errors Register
Name: EMAC_RSE
Address: 0x400B0074
Access: Read-write
• RSE: Receive Symbol Errors
An 8-bit register counting the number of frames that had rx_er asserted during reception. Receive symbol errors are also
counted as an FCS or alignment error if the frame is between 64 and 1518 bytes in length (1536 if bit 8 is set in the network
configuration register). If the frame is larger, it is recorded as a jabber error.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
RSE
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41.6.26.16Excessive Length Errors Register
Name: EMAC_ELE
Address: 0x400B0078
Access: Read-write
• EXL: Excessive Length Errors
An 8-bit register counting the number of frames received exceeding 1518 bytes (1536 if bit 8 set in network configuration
register) in length but do not have either a CRC error, an alignment error nor a receive symbol error.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
EXL
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41.6.26.17Receive Jabbers Register
Name: EMAC_RJA
Address: 0x400B007C
Access: Read-write
• RJB: Receive Jabbers
An 8-bit register counting the number of frames received exceeding 1518 bytes (1536 if bit 8 set in network configuration
register) in length and have either a CRC error, an alignment error or a receive symbol error.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
RJB
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41.6.26.18Undersize Frames Register
Name: EMAC_USF
Address: 0x400B0080
Access: Read-write
• USF: Undersize frames
An 8-bit register counting the number of frames received less than 64 bytes in length but do not have either a CRC error,
an alignment error or a receive symbol error.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
USF
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41.6.26.19SQE Test Errors Register
Name: EMAC_STE
Address: 0x400B0084
Access: Read-write
• SQER: SQE test errors
An 8-bit register counting the number of frames where col was not asserted within 96 bit times (an interframe gap) of
tx_en being deasserted in half duplex mode.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
SQER
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41.6.26.20Received Length Field Mismatch Register
Name: EMAC_RLE
Address: 0x400B0088
Access: Read-write
• RLFM: Receive Length Field Mismatch
An 8-bit register counting the number of frames received that have a measured length shorter than that extracted from its
length field. Checking is enabled through bit 16 of the network configuration register. Frames containing a type ID in bytes
13 and 14 (i.e., length/type ID = 0x0600) are not counted as length field errors, neither are excessive length frames.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
RLFM
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42. True Random Number Generator (TRNG)
42.1 Description
The True Random Number Generator (TRNG) passes the American NIST Special Publication 800-22 and Diehard
Random Tests Suites.
As soon as the TRNG is enabled (TRNG_CTRL register), the generator provides one 32-bit value every 84 clock
cycles. Interrupt trng_int can be enabled through the TRNG_IER register (respectively disabled in TRNG_IDR).
This interrupt is set when a new random value is available and is cleared when the status register is read
(TRNG_SR register). The flag DATRDY of the status register (TRNG_ISR) is set when the random data is ready to
be read out on the 32-bit output data register (TRNG_ODATA).
The normal mode of operation checks that the status register flag equals 1 before reading the output data register
when a 32-bit random value is required by the software application.
Figure 42-1. TRNG Data Generation Sequence
42.2 Embedded Characteristics
Passed NIST Special Publication 800-22 Tests Suite
Passed Diehard Random Tests Suite
Provides a 32-bit Random Number Every 84 Clock Cycles
84 clock cycles84 clock cycles
84 clock cycles
Read TRNG_ISR
Read TRNG_ODATA
Read TRNG_ISR
Read TRNG_ODATA
clock
trng_int
trng_cr
enable
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42.3 True Random Number Generator (TRNG) User Interface
Table 42-1. Register Mapping
Offset Register Name Access Reset
0x00 Control Register TRNG_CR Write-only –
0x10 Interrupt Enable Register TRNG_IER Write-only –
0x14 Interrupt Disable Register TRNG_IDR Write-only –
0x18 Interrupt Mask Register TRNG_IMR Read-only 0x0000_0000
0x1C Interrupt Status Register TRNG_ISR Read-only 0x0000_0000
0x50 Output Data Register TRNG_ODATA Read-only 0x0000_0000
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42.3.1 TRNG Control Register
Name: TRNG_CR
Address: 0x400BC000
Access: Write-only
• ENABLE: Enables the TRNG to provide random values
0: Disables the TRNG.
1: Enables the TRNG.
• KEY: Security Key
KEY = 0x524e47 (RNG in ASCII)
This key is to be written when the ENABLE bit is set or cleared.
3130292827 26 25 24
KEY
2322 21 20 19 1817 16
KEY
15 14 1312 11 10 9 8
KEY
76543210
–––––––ENABLE
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42.3.2 TRNG Interrupt Enable Register
Name: TRNG_IER
Address: 0x400BC010
Access: Write-only
• DATRDY: Data Ready Interrupt Enable
0: No effect.
1: Enables the corresponding interrupt.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–––––––DATRDY
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42.3.3 TRNG Interrupt Disable Register
Name: TRNG_IDR
Address: 0x400BC014
Access: Write-only
• DATRDY: Data Ready Interrupt Disable
0: No effect.
1: Disables the corresponding interrupt.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–––––––DATRDY
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42.3.4 TRNG Interrupt Mask Register
Name: TRNG_IMR
Address: 0x400BC018
Reset: 0x0000_0000
Access: Read-only
• DATRDY: Data Ready Interrupt Mask
0: The corresponding interrupt is not enabled.
1: The corresponding interrupt is enabled.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––––
76543210
–––––––DATRDY
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42.3.5 TRNG Interrupt Status Register
Name: TRNG_ISR
Address: 0x400BC01C
Reset: 0x0000_0000
Access: Read-only
• DATRDY: Data Ready
0: Output data is not valid or TRNG is disabled.
1: New Random value is completed.
DATRDY is cleared when this register is read.
3130292827 26 25 24
––––––––
2322 21 20 19 1817 16
––––––––
15 14 1312 11 10 9 8
––––––
76543210
–––––––DATRDY
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42.3.6 TRNG Output Data Register
Name: TRNG_ODATA
Address: 0x400BC050
Reset: 0x0000_0000
Access: Read-only
• ODATA: Output Data
The 32-bit Output Data register contains the 32-bit random data.
3130292827 26 25 24
ODATA
2322 21 20 19 1817 16
ODATA
15 14 1312 11 10 9 8
ODATA
76543210
ODATA
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43. Analog-to-Digital Converter (ADC)
43.1 Description
The ADC is based on a 12-bit Analog-to-Digital Converter (ADC) managed by an ADC Controller. Refer to the
Block Diagram: Figure 43-1. It also integrates a 16-to-1 analog multiplexer, making possible the analog-to-digital
conversions of 16 analog lines. The conversions extend from 0V to ADVREF. The ADC supports an 10-bit or 12-
bit resolution mode, and conversion results are reported in a common register for all channels, as well as in a
channel-dedicated register. Software trigger, external trigger on rising edge of the ADTRG pin or internal triggers
from Timer Counter output(s) are configurable.
The comparison circuitry allows automatic detection of values below a threshold, higher than a threshold, in a
given range or outside the range, thresholds and ranges being fully configurable.
The ADC Controller internal fault output is directly connected to PWM Fault input. This input can be asserted by
means of comparison circuitry in order to immediately put the PWM outputs in a safe state (pure combinational
path).
The ADC also integrates a Sleep Mode and a conversion sequencer and connects with a PDC channel. These
features reduce both power consumption and processor intervention.
This ADC has a selectable single-ended or fully differential input and benefits from a 2-bit programmable gain. A
whole set of reference voltages is generated internally from a single external reference voltage node that may be
equal to the analog supply voltage. An external decoupling capacitance is required for noise filtering.
A digital error correction circuit based on the multi-bit redundant signed digit (RSD) algorithm is employed in order
to reduce INL and DNL errors.
Finally, the user can configure ADC timings, such as Startup Time and Tracking Time.
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43.2 Embedded Characteristics
12-bit Resolution
1 MHz Conversion Rate
Wide Range Power Supply Operation
Selectable Single Ended or Differential Input Voltage
Programmable Gain For Maximum Full Scale Input Range 0 - VDD
Integrated Multiplexer Offering Up to 16 Independent Analog Inputs
Individual Enable and Disable of Each Channel
Hardware or Software Trigger
̶External Trigger Pin
̶Timer Counter Outputs (Corresponding TIOA Trigger)
̶PWM Event Line
Drive of PWM Fault Input
PDC Support
Possibility of ADC Timings Configuration
Two Sleep Modes and Conversion Sequencer
̶Automatic Wakeup on Trigger and Back to Sleep Mode after Conversions of all Enabled Channels
̶Possibility of Customized Channel Sequence
Standby Mode for Fast Wakeup Time Response
̶Power Down Capability
Automatic Window Comparison of Converted Values
Write Protect Registers
43.3 Block Diagram
Figure 43-1. Analog-to-Digital Converter Block Diagram
ADTRG
ADVREF
GND
VDDANA
Trigger
Selection
Timer
Counter
Channels
AD0
AD1
ADn
Analog
Inputs
ADC Interrupt
ADC 12-Bit Controller
ADC cell
Control
Logic
User
Interface
Interrupt
Controller
Peripheral Bridge
APB
PDC
AHB
IN+
IN- S/H
OFFSET PGA
PIO
Cyclic Pipeline
12-bit Analog-to-Digital
Converter
CHx
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43.4 Signal Description
Note: 1. AD15 is not an actual pin but is connected to a temperature sensor.
43.5 Product Dependencies
43.5.1 Power Management
The ADC Controller is not continuously clocked. The programmer must first enable the ADC Controller MCK in the
Power Management Controller (PMC) before using the ADC Controller. However, if the application does not
require ADC operations, the ADC Controller clock can be stopped when not needed and restarted when
necessary. Configuring the ADC Controller does not require the ADC Controller clock to be enabled.
43.5.2 Interrupt Sources
The ADC interrupt line is connected on one of the internal sources of the Interrupt Controller. Using the ADC
interrupt requires the NVIC to be programmed first.
43.5.3 Analog Inputs
The analog input pins can be multiplexed with PIO lines. In this case, the assignment of the ADC input is
automatically done as soon as the corresponding channel is enabled by writing the register ADC_CHER. By
default, after reset, the PIO line is configured as input with its pull-up enabled and the ADC input is connected to
the GND.
43.5.4 Temperature Sensor
The temperature sensor is connected to Channel 15 of the ADC.
The temperature sensor provides an output voltage VT that is proportional to absolute temperature (PTAT). To
activate the temperature sensor, TSON bit (ADC_ACR) needs to be set.
Table 43-1. ADC Pin Description
Pin Name Description
VDDANA Analog power supply
ADVREF Reference voltage(1)
AD0 - AD15 Analog input channels
ADTRG External trigger
Table 43-2. Peripheral IDs
Instance ID
ADC 37
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43.5.5 I/O Lines
The pin ADTRG may be shared with other peripheral functions through the PIO Controller. In this case, the PIO
Controller should be set accordingly to assign the pin ADTRG to the ADC function.
43.5.6 Timer Triggers
Timer Counters may or may not be used as hardware triggers depending on user requirements. Thus, some or all
of the timer counters may be unconnected.
43.5.7 PWM Event Line
PWM Event Lines may or may not be used as hardware triggers depending on user
requirements.
43.5.8 Fault Output
The ADC Controller has the FAULT output connected to the FAULT input of PWM. Please refer to Section 43.6.12
”Fault Output” and implementation of the PWM in the product.
43.5.9 Conversion Performances
For performance and electrical characteristics of the ADC, see the product DC Characteristics section.
Table 43-3. I/O Lines
Instance Signal I/O Line Peripheral
ADC ADTRG PA11 B
ADC AD0 PA2 X1
ADC AD1/WKUP1 PA3 X1
ADC AD2 PA4 X1
ADC AD3 PA6 X1
ADC AD4 PA22 X1
ADC AD5 PA23 X1
ADC AD6 PA24 X1
ADC AD7 PA16 X1
ADC AD8 PB12 X1
ADC AD9 PB13 X1
ADC AD10 PB17 X1
ADC AD11 PB18 X1
ADC AD12 PB19 X1
ADC AD13 PB20 X1
ADC AD14/WKUP13 PB21 X1
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43.6 Functional Description
43.6.1 Analog-to-digital Conversion
The ADC uses the ADC Clock to perform conversions. Converting a single analog value to a 12-bit digital data
requires Tracking Clock cycles as defined in the field TRACKTIM of the “ADC Mode Register” on page 1333 and
Transfer Clock cycles as defined in the field TRANSFER of the same register. The ADC Clock frequency is
selected in the PRESCAL field of the Mode Register (ADC_MR). The tracking phase starts during the conversion
of the previous channel. If the tracking time is longer than the conversion time, the tracking phase is extended to
the end of the previous conversion.
The ADC clock range is between MCK/2, if PRESCAL is 0, and MCK/512, if PRESCAL is set to 255 (0xFF).
PRESCAL must be programmed in order to provide an ADC clock frequency according to the parameters given in
the product Electrical Characteristics section.
Figure 43-2. Sequence of ADC conversions when Tracking time > Conversion time
ADCClock
LCDR
ADC_ON
Trigger event (Hard or Soft)
ADC_SEL
DRDY
ADC_Start
CH0 CH1
CH0
CH2
CH1
Transfer Period Transfer PeriodStart Up
Time
(and tracking of CH0)
Conversion
of CH0 Conversion
of CH1
Tracking of CH1 Tracking of CH2
Commands
from controller
to analog cell
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Figure 43-3. Sequence of ADC conversions when Tracking time < Conversion time
43.6.2 Conversion Reference
The conversion is performed on a full range between 0V and the reference voltage pin ADVREF. Analog inputs
between these voltages convert to values based on a linear conversion.
43.6.3 Conversion Resolution
The ADC supports 10-bit or 12-bit resolutions. The 10-bit selection is performed by setting the LOWRES bit in the
ADC Mode Register (ADC_MR). By default, after a reset, the resolution is the highest and the DATA field in the
data registers is fully used. By setting the LOWRES bit, the ADC switches to the lowest resolution and the
conversion results can be read in the lowest significant bits of the data registers. The two highest bits of the DATA
field in the corresponding ADC_CDR register and of the LDATA field in the ADC_LCDR register read 0.
Moreover, when a PDC channel is connected to the ADC, 12-bit or 10-bit resolution sets the transfer request size
to 16 bits.
43.6.4 Conversion Results
When a conversion is completed, the resulting 12-bit digital value is stored in the Channel Data Register
(ADC_CDRx) of the current channel and in the ADC Last Converted Data Register (ADC_LCDR). By setting the
TAG option in the ADC_EMR, the ADC_LCDR presents the channel number associated to the last converted data
in the CHNB field.
The channel EOC bit in the Status Register (ADC_SR) is set and the DRDY is set. In the case of a connected
PDC channel, DRDY rising triggers a data transfer request. In any case, either EOC and DRDY can trigger an
interrupt.
Reading one of the ADC_CDR registers clears the corresponding EOC bit. Reading ADC_LCDR clears the DRDY
bit and EOC bit corresponding to the last converted channel.
ADCClock
LCDR
ADC_ON
Trigger event (Hard or Soft)
ADC_SEL
DRDY
ADC_Start
CH0 CH1
CH0
CH2
CH1
CH3
CH2
Transfer Period Transfer Period Transfer PeriodStart Up
Time
&
Tracking
of CH0
Conversion
of CH0
&
Tracking
of CH1
Conversion
of CH1
&
Tracking
of CH2
Conversion
of CH2
&
Tracking
of CH3
Read the
ADC_LCDR
Commands
from controller
to analog cell
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Figure 43-4. EOCx and DRDY Flag Behavior
If the ADC_CDR is not read before further incoming data is converted, the corresponding Overrun Error (OVREx)
flag is set in the Overrun Status Register (ADC_OVER).
Likewise, new data converted when DRDY is high sets the GOVRE bit (General Overrun Error) in ADC_SR.
The OVREx flag is automatically cleared when ADC_OVER is read, and GOVRE flag is automatically cleared
when ADC_SR is read.
Read the ADC_CDRx
EOCx
DRDY
Read the ADC_LCDR
CHx
(ADC_CHSR)
(ADC_SR)
(ADC_SR)
Write the ADC_CR
with START = 1
Write the ADC_CR
with START = 1
Undsliri‘e X 1 Dai : I x w “—> ‘.<—>1 _ AtmeL
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Figure 43-5. GOVRE and OVREx Flag Behavior
Warning: If the corresponding channel is disabled during a conversion or if it is disabled and then reenabled
during a conversion, its associated data and its corresponding EOC and OVRE flags in ADC_SR are
unpredictable.
EOC0
GOVRE
CH0
(ADC_CHSR)
(ADC_SR)
(ADC_SR)
Trigger event
EOC1
CH1
(ADC_CHSR)
(ADC_SR)
OVRE0
(ADC_OVER)
Undefined Data Data A Data B
ADC_LCDR
Undefined Data Data A
ADC_CDR0
Undefined Data Data B
ADC_CDR1
Data C
Data C
Conversion C
Conversion A
DRDY
(ADC_SR)
Read ADC_CDR1
Read ADC_CDR0
Conversion B
Read ADC_OVER
Read ADC_SR
OVRE1
(ADC_OVER)
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43.6.5 Conversion Triggers
Conversions of the active analog channels are started with a software or hardware trigger. The software trigger is
provided by writing the Control Register (ADC_CR) with the START bit at 1.
The hardware trigger can be one of the TIOA outputs of the Timer Counter channels, PWM Event line, or the
external trigger input of the ADC (ADTRG). The hardware trigger is selected with the TRGSEL field in the Mode
Register (ADC_MR). The selected hardware trigger is enabled with the TRGEN bit in the Mode Register
(ADC_MR).
The minimum time between 2 consecutive trigger events must be strictly greater than the duration time of the
longest conversion sequence according to configuration of registers ADC_MR, ADC_CHSR, ADC_SEQR1,
ADC_SEQR2.
If a hardware trigger is selected, the start of a conversion is triggered after a delay starting at each rising edge of
the selected signal. Due to asynchronous handling, the delay may vary in a range of 2 MCK clock periods to 1
ADC clock period.
If one of the TIOA outputs is selected, the corresponding Timer Counter channel must be programmed in
Waveform Mode.
Only one start command is necessary to initiate a conversion sequence on all the channels. The ADC hardware
logic automatically performs the conversions on the active channels, then waits for a new request. The Channel
Enable (ADC_CHER) and Channel Disable (ADC_CHDR) Registers permit the analog channels to be enabled or
disabled independently.
If the ADC is used with a PDC, only the transfers of converted data from enabled channels are performed and the
resulting data buffers should be interpreted accordingly.
43.6.6 Sleep Mode and Conversion Sequencer
The ADC Sleep Mode maximizes power saving by automatically deactivating the ADC when it is not being used for
conversions. Sleep Mode is selected by setting the SLEEP bit in the Mode Register ADC_MR.
The Sleep mode is automatically managed by a conversion sequencer, which can automatically process the
conversions of all channels at lowest power consumption.
This mode can be used when the minimum period of time between 2 successive trigger events is greater than the
startup period of Analog-Digital converter (See the product ADC Characteristics section).
When a start conversion request occurs, the ADC is automatically activated. As the analog cell requires a start-up
time, the logic waits during this time and starts the conversion on the enabled channels. When all conversions are
complete, the ADC is deactivated until the next trigger. Triggers occurring during the sequence are not taken into
account.
A fast wake-up mode is available in the ADC Mode Register (ADC_MR) as a compromise between power saving
strategy and responsiveness. Setting the FWUP bit to ‘1’ enables the fast wake-up mode. In fast wake-up mode
the ADC cell is not fully deactivated while no conversion is requested, thereby providing less power saving but
faster wakeup.
The conversion sequencer allows automatic processing with minimum processor intervention and optimized power
consumption. Conversion sequences can be performed periodically using a Timer/Counter output or the PWM
event line. The periodic acquisition of several samples can be processed automatically without any intervention of
the processor thanks to the PDC.
The sequence can be customized by programming the Sequence Channel Registers, ADC_SEQR1 and
ADC_SEQR2 and setting to 1 the USEQ bit of the Mode Register (ADC_MR). The user can choose a specific
trigger
start
delay
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order of channels and can program up to 16 conversions by sequence. The user is totally free to create a personal
sequence, by writing channel numbers in ADC_SEQR1 and ADC_SEQR2. Not only can channel numbers be
written in any sequence, channel numbers can be repeated several times. Only enabled sequence bitfields are
converted, consequently to program a 15-conversion sequence, the user can simply put a disable in
ADC_CHSR[15], thus disabling the 16THCH field of ADC_SEQR2.
If all ADC channels (i.e. 16) are used on an application board, there is no restriction of usage of the user sequence.
But as soon as some ADC channels are not enabled for conversion but rather used as pure digital inputs, the
respective indexes of these channels cannot be used in the user sequence fields (ADC_SEQR1, ADC_SEQR2
bitfields). For example, if channel 4 is disabled (ADC_CSR[4] = 0), ADC_SEQR1, ADC_SEQR2 register bitfields
USCH1 up to USCH16 must not contain the value 4. Thus the length of the user sequence may be limited by this
behavior.
As an example, if only 4 channels over 16 (CH0 up to CH3) are selected for ADC conversions, the user sequence
length cannot exceed 4 channels. Each trigger event may launch up to 4 successive conversions of any
combination of channels 0 up to 3 but no more (i.e. in this case the sequence CH0, CH0, CH1, CH1, CH1 is
impossible).
A sequence that repeats several times the same channel requires more enabled channels than channels actually
used for conversion. For example, a sequence like CH0, CH0, CH1, CH1 requires 4 enabled channels (4 free
channels on application boards) whereas only CH0, CH1 are really converted.
Note: The reference voltage pins always remain connected in normal mode as in sleep mode.
43.6.7 Comparison Window
The ADC Controller features automatic comparison functions. It compares converted values to a low threshold or a
high threshold or both, according to the CMPMODE function chosen in the Extended Mode Register (ADC_EMR).
The comparison can be done on all channels or only on the channel specified in CMPSEL field of ADC_EMR. To
compare all channels the CMP_ALL parameter of ADC_EMR should be set.
Moreover a filtering option can be set by writing the number of consecutive comparison errors needed to raise the
flag. This number can be written and read in the CMPFILTER field of ADC_EMR.
The flag can be read on the COMPE bit of the Interrupt Status Register (ADC_ISR) and can trigger an interrupt.
The High Threshold and the Low Threshold can be read/write in the Comparison Window Register (ADC_CWR).
43.6.8 Differential Inputs
The ADC can be used either as a single ended ADC (DIFF bit equal to 0) or as a fully differential ADC (DIFF bit
equal to 1) as shown in Figure 43-6. By default, after a reset, the ADC is in single ended mode.
If ANACH is set in ADC_MR the ADC can apply a different mode on each channel. Otherwise the parameters of
CH0 are applied to all channels.
The same inputs are used in single ended or differential mode.
In single ended mode, inputs are managed by a 16:1 channels analog multiplexer. In the fully differential mode,
inputs are managed by an 8:1 channels analog multiplexer. See Table 43-4 and Table 43-5.
Table 43-4. Input Pins and Channel Number in Single Ended Mode
Input Pins Channel Number
AD0 CH0
AD1 CH1
AD2 CH2
AD3 CH3
AD4 CH4
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43.6.9 Input Gain and Offset
The ADC has a built in Programmable Gain Amplifier (PGA) and Programmable Offset.
The Programmable Gain Amplifier can be set to gains of 1/2, 1, 2 and 4. The Programmable Gain Amplifier can be
used either for single ended applications or for fully differential applications.
If ANACH is set in ADC_MR the ADC can apply different gain and offset on each channel. Otherwise the
parameters of CH0 are applied to all channels.
The gain is configurable through the GAIN bit of the Channel Gain Register (ADC_CGR) as shown in Table 43-6.
AD5 CH5
AD6 CH6
AD7 CH7
AD8 CH8
AD9 CH9
AD10 CH10
AD11 CH11
AD12 CH12
AD13 CH13
AD14 CH14
AD15 CH15
Table 43-5. Input Pins and Channel Number In Differential Mode
Input Pins Channel Number
AD0-AD1 CH0
AD2-AD3 CH2
AD4-AD5 CH4
AD6-AD7 CH6
AD8-AD9 CH8
AD10-AD11 CH10
AD12-AD13 CH12
AD14-AD15 CH14
Table 43-4. Input Pins and Channel Number in Single Ended Mode (Continued)
Input Pins Channel Number
Table 43-6. Gain of the Sample and Hold Unit: GAIN Bits and DIFF Bit.
GAIN<0:1> GAIN (DIFF = 0) GAIN (DIFF = 1)
00 1 0.5
01 1 1
10 2 2
11 4 2
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To allow full range, analog offset of the ADC can be configured by the OFFSET bit of the Channel Offset Register
(ADC_COR). The Offset is only available in Single Ended Mode.
Figure 43-6. Analog Full Scale Ranges in Single Ended/Differential Applications Versus Gain and Offset
Table 43-7. Offset of the Sample and Hold Unit: OFFSET DIFF and Gain (G)
OFFSET Bit OFFSET (DIFF = 0) OFFSET (DIFF = 1)
00 0
1(G-1)Vrefin/2
VIN+
gain=0.5
gain=1
gain=2
gain=4
single ended
se0fd1=0 fully differential
se0fd1=1
same as
gain=1
same as
gain=2
0
vrefin
(½)vrefin
vrefin
0
(¾)vrefin
(¼)vrefin
(½)vrefin
vrefin
0
(5/8)vrefin
(3/8)vrefin
(½)vrefin
offset=0offset=1
offset=0offset=1
(¼)vrefin
vrefin
0
(5/8)vrefin
(3/8)vrefin
(½)vrefin
(¼)vrefin
(¾)vrefin
(1/8)vrefin
(00)
(01)
(10)
(11)
VIN+
VIN+
VIN+
VIN+
VIN+
VIN+
VIN-
VIN+
VIN-
VIN+
VIN-
VIN+
VIN-
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43.6.10 ADC Timings
Each ADC has its own minimal Startup Time that is programmed through the field STARTUP in the Mode Register,
ADC_MR.
A minimal Tracking Time is necessary for the ADC to guarantee the best converted final value between two
channel selections. This time has to be programmed through the TRACKTIM bit field in the Mode Register,
ADC_MR.
When the gain, offset or differential input parameters of the analog cell change between two channels, the analog
cell may need a specific settling time before starting the tracking phase. In that case, the controller automatically
waits during the settling time defined in the “ADC Mode Register”. Obviously, if the ANACH option is not set, this
time is unused.
Warning: No input buffer amplifier to isolate the source is included in the ADC. This must be taken into
consideration to program a precise value in the TRACKTIM field. See the product ADC Characteristics section.
43.6.11 Buffer Structure
The PDC read channel is triggered each time a new data is stored in ADC_LCDR register. The same structure of
data is repeatedly stored in ADC_LCDR register each time a trigger event occurs. Depending on user mode of
operation (ADC_MR, ADC_CHSR, ADC_SEQR1, ADC_SEQR2) the structure differs. Each data transferred to
PDC buffer, carried on a half-word (16-bit), consists of last converted data right aligned and when TAG is set in
ADC_EMR register, the 4 most significant bits are carrying the channel number thus allowing an easier post-
processing in the PDC buffer or better checking the PDC buffer integrity.
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43.6.12 Fault Output
The ADC Controller internal fault output is directly connected to PWM fault input. Fault output may be asserted
according to the configuration of ADC_EMR (Extended Mode Register) and ADC_CWR (Compare Window
Register) and converted values. When the Compare occurs, the ADC fault output generates a pulse of one Master
Clock Cycle to the PWM fault input. This fault line can be enabled or disabled within PWM. Should it be activated
and asserted by the ADC Controller, the PWM outputs are immediately placed in a safe state (pure combinational
path). Note that the ADC fault output connected to the PWM is not the COMPE bit. Thus the Fault Mode (FMOD)
within the PWM configuration must be FMOD = 1.
43.6.13 Write Protection Registers
To prevent any single software error that may corrupt ADC behavior, certain address spaces can be write-
protected by setting the WPEN bit in the “ADC Write Protect Mode Register” (ADC_WPMR).
If a write access to the protected registers is detected, then the WPVS flag in the ADC Write Protect Status
Register (ADC_WPSR) is set and the field WPVSRC indicates in which register the write access has been
attempted.
The WPVS flag is reset by writing the ADC Write Protect Mode Register (ADC_WPMR) with the appropriate
access key, WPKEY.
The protected registers are:
“ADC Mode Register” on page 1333
“ADC Channel Sequence 1 Register” on page 1336
“ADC Channel Sequence 2 Register” on page 1337
“ADC Channel Enable Register” on page 1338
“ADC Channel Disable Register” on page 1339
“ADC Extended Mode Register” on page 1347
“ADC Compare Window Register” on page 1348
“ADC Channel Gain Register” on page 1349
“ADC Channel Offset Register” on page 1350
“ADC Analog Control Register” on page 1352
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43.7 Analog-to-Digital Converter (ADC) User Interface
Any offset not listed in Table 43-8 must be considered as “reserved”.
Note: If an offset is not listed in the table it must be considered as “reserved”.
Table 43-8. Register Mapping
Offset Register Name Access Reset
0x00 Control Register ADC_CR Write-only –
0x04 Mode Register ADC_MR Read-write 0x00000000
0x08Channel Sequence Register 1 ADC_SEQR1 Read-write 0x00000000
0x0C Channel Sequence Register 2 ADC_SEQR2 Read-write 0x00000000
0x10 Channel Enable Register ADC_CHER Write-only –
0x14 Channel Disable Register ADC_CHDR Write-only –
0x18Channel Status Register ADC_CHSRRead-only 0x00000000
0x1C Reserved – – –
0x20 Last Converted Data Register ADC_LCDR Read-only 0x00000000
0x24 Interrupt Enable Register ADC_IER Write-only –
0x28Interrupt Disable Register ADC_IDR Write-only –
0x2C Interrupt Mask Register ADC_IMR Read-only 0x00000000
0x30 Interrupt Status Register ADC_ISRRead-only 0x00000000
0x34Reserved – – –
0x38 Reserved – – –
0x3COverrun Status Register ADC_OVER Read-only 0x00000000
0x40 Extended Mode Register ADC_EMR Read-write 0x00000000
0x44 Compare Window Register ADC_CWR Read-write 0x00000000
0x48Channel Gain Register ADC_CGR Read-write 0x00000000
0x4C Channel Offset Register ADC_COR Read-write 0x00000000
0x50 Channel Data Register 0 ADC_CDR0 Read-only 0x00000000
0x54 Channel Data Register 1 ADC_CDR1 Read-only 0x00000000
... ... ... ... ...
0x8CChannel Data Register 15 ADC_CDR15 Read-only 0x00000000
0x90 - 0x90 Reserved – – –
0x94 Analog Control Register ADC_ACR Read-write 0x00000100
0x98 - 0xAC Reserved – – –
0xC4 - 0xE0 Reserved – – –
0xE4 Write Protect Mode Register ADC_WPMR Read-write 0x00000000
0xE8Write Protect Status Register ADC_WPSRRead-only 0x00000000
0xEC - 0xF8Reserved – – –
0xFC Reserved – – –
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43.7.1 ADC Control Register
Name: ADC_CR
Address: 0x400C0000
Access: Write-only
• SWRST: Software Reset
0 = No effect.
1 = Resets the ADC simulating a hardware reset.
• START: Start Conversion
0 = No effect.
1 = Begins analog-to-digital conversion.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––STARTSWRST
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43.7.2 ADC Mode Register
Name: ADC_MR
Address: 0x400C0004
Access: Read-write
This register can only be written if the WPEN bit is cleared in “ADC Write Protect Mode Register” on page 1353.
• TRGEN: Trigger Enable
• TRGSEL: Trigger Selection
• LOWRES: Resolution
• SLEEP: Sleep Mode
31 30 29 28 27 26 25 24
USEQ – TRANSFER TRACKTIM
23 22 21 20 19 18 17 16
ANACH – SETTLING STARTUP
15 14 13 12 11 10 9 8
PRESCAL
76543210
FREERUN FWUP SLEEP LOWRES TRGSEL TRGEN
Value Name Description
0 DIS Hardware triggers are disabled. Starting a conversion is only possible by software.
1 EN Hardware trigger selected by TRGSEL field is enabled.
Value Name Description
0 ADC_TRIG0 External : ADCTRG
1 ADC_TRIG1 TIOA Output of the Timer Counter Channel 0
2 ADC_TRIG2 TIOA Output of the Timer Counter Channel 1
3 ADC_TRIG3 TIOA Output of the Timer Counter Channel 2
4 ADC_TRIG4 PWM Event Line 0
5 ADC_TRIG5 PWM Event Line 0
6 ADC_TRIG6 Reserved
7–Reserved
Value Name Description
0 BITS_12 12-bit resolution
1 BITS_10 10-bit resolution
Value Name Description
0 NORMAL Normal Mode: The ADC Core and reference voltage circuitry are kept ON between conversions
1 SLEEP Sleep Mode: The ADC Core and reference voltage circuitry are OFF between conversions
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• FWUP: Fast Wake Up
• FREERUN: Free Run Mode
• PRESCAL: Prescaler Rate Selection
ADCClock = MCK / ( (PRESCAL+1) * 2 )
• STARTUP: Start Up Time
• SETTLING: Analog Settling Time
Value Name Description
0 OFF Normal Sleep Mode: The sleep mode is defined by the SLEEP bit
1 ON Fast Wake Up Sleep Mode: The Voltage reference is ON between conversions and ADC Core is OFF
Value Name Description
0 OFF Normal Mode
1 ON Free Run Mode: Never wait for any trigger.
Value Name Description
0 SUT0 0 periods of ADCClock
1 SUT8 8 periods of ADCClock
2 SUT16 16 periods of ADCClock
3 SUT24 24 periods of ADCClock
4 SUT64 64 periods of ADCClock
5 SUT80 80 periods of ADCClock
6 SUT96 96 periods of ADCClock
7 SUT112 112 periods of ADCClock
8 SUT512 512 periods of ADCClock
9 SUT576 576 periods of ADCClock
10 SUT640 640 periods of ADCClock
11 SUT704 704 periods of ADCClock
12 SUT768 768 periods of ADCClock
13 SUT832 832 periods of ADCClock
14 SUT896 896 periods of ADCClock
15 SUT960 960 periods of ADCClock
Value Name Description
0 AST3 3 periods of ADCClock
1 AST5 5 periods of ADCClock
2 AST9 9 periods of ADCClock
3 AST17 17 periods of ADCClock
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• ANACH: Analog Change
• TRACKTIM: Tracking Time
Tracking Time = (TRACKTIM + 1) * ADCClock periods.
• TRANSFER: Transfer Period
Transfer Period = (TRANSFER * 2 + 3) ADCClock periods.
• USEQ: Use Sequence Enable
Value Name Description
0 NONE No analog change on channel switching: DIFF0, GAIN0 and OFF0 are used for all channels
1 ALLOWED Allows different analog settings for each channel. See ADC_CGR and ADC_COR Registers
Value Name Description
0 NUM_ORDER Normal Mode: The controller converts channels in a simple numeric order.
1REG_ORDER
User Sequence Mode: The sequence respects what is defined in ADC_SEQR1 and ADC_SEQR2
registers.
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43.7.3 ADC Channel Sequence 1 Register
Name: ADC_SEQR1
Address: 0x400C0008
Access: Read-write
This register can only be written if the WPEN bit is cleared in “ADC Write Protect Mode Register” on page 1353.
• USCHx: User Sequence Number x
The sequence number x (USCHx) can be programmed by the Channel number CHy where y is the value written in this
field. The allowed range is 0 up to 15. So it is only possible to use the sequencer from CH0 to CH15.
This register activates only if ADC_MR(USEQ) field is set to ‘1’.
Any USCHx field is taken into account only if ADC_CHSR(CHx) register field reads logical ‘1’ else any value written in
USCHx does not add the corresponding channel in the conversion sequence.
Configuring the same value in different fields leads to multiple samples of the same channel during the conversion
sequence. This can be done consecutively, or not, according to user needs.
31 30 29 28 27 26 25 24
USCH8 USCH7
23 22 21 20 19 18 17 16
USCH6 USCH5
15 14 13 12 11 10 9 8
USCH4 USCH3
76543210
USCH2 USCH1
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43.7.4 ADC Channel Sequence 2 Register
Name: ADC_SEQR2
Address: 0x400C000C
Access: Read-write
This register can only be written if the WPEN bit is cleared in “ADC Write Protect Mode Register” on page 1353.
• USCHx: User Sequence Number x
The sequence number x (USCHx) can be programmed by the Channel number CHy where y is the value written in this
field. The allowed range is 0 up to 15. So it is only possible to use the sequencer from CH0 to CH15.
This register activates only if ADC_MR(USEQ) field is set to ‘1’.
Any USCHx field is taken into account only if ADC_CHSR(CHx) register field reads logical ‘1’ else any value written in
USCHx does not add the corresponding channel in the conversion sequence.
Configuring the same value in different fields leads to multiple samples of the same channel during the conversion
sequence. This can be done consecutively, or not, according to user needs.
31 30 29 28 27 26 25 24
USCH16 USCH15
23 22 21 20 19 18 17 16
USCH14 USCH13
15 14 13 12 11 10 9 8
USCH12 USCH11
76543210
USCH10 USCH9
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43.7.5 ADC Channel Enable Register
Name: ADC_CHER
Address: 0x400C0010
Access: Write-only
This register can only be written if the WPEN bit is cleared in “ADC Write Protect Mode Register” on page 1353.
• CHx: Channel x Enable
0 = No effect.
1 = Enables the corresponding channel.
Note: if USEQ = 1 in ADC_MR register, CHx corresponds to the xth channel of the sequence described in ADC_SEQR1
and ADC_SEQR2.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CH15 CH14 CH13 CH12 CH11 CH10 CH9 CH8
76543210
CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0
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43.7.6 ADC Channel Disable Register
Name: ADC_CHDR
Address: 0x400C0014
Access: Write-only
This register can only be written if the WPEN bit is cleared in “ADC Write Protect Mode Register” on page 1353.
• CHx: Channel x Disable
0 = No effect.
1 = Disables the corresponding channel.
Warning: If the corresponding channel is disabled during a conversion or if it is disabled then reenabled during a conver-
sion, its associated data and its corresponding EOC and OVRE flags in ADC_SR are unpredictable.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CH15 CH14 CH13 CH12 CH11 CH10 CH9 CH8
76543210
CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0
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43.7.7 ADC Channel Status Register
Name: ADC_CHSR
Address: 0x400C0018
Access: Read-only
• CHx: Channel x Status
0 = Corresponding channel is disabled.
1 = Corresponding channel is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CH15 CH14 CH13 CH12 CH11 CH10 CH9 CH8
76543210
CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0
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43.7.8 ADC Last Converted Data Register
Name: ADC_LCDR
Address: 0x400C0020
Access: Read-only
• LDATA: Last Data Converted
The analog-to-digital conversion data is placed into this register at the end of a conversion and remains until a new conver-
sion is completed.
• CHNB: Channel Number
Indicates the last converted channel when the TAG option is set to 1 in ADC_EMR register. If TAG option is not set,
CHNB = 0.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CHNB LDATA
76543210
LDATA
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43.7.9 ADC Interrupt Enable Register
Name: ADC_IER
Address: 0x400C0024
Access: Write-only
• EOCx: End of Conversion Interrupt Enable x
• DRDY: Data Ready Interrupt Enable
• GOVRE: General Overrun Error Interrupt Enable
• COMPE: Comparison Event Interrupt Enable
• ENDRX: End of Receive Buffer Interrupt Enable
• RXBUFF: Receive Buffer Full Interrupt Enable
0 = No effect.
1 = Enables the corresponding interrupt.
31 30 29 28 27 26 25 24
– – – RXBUFF ENDRX COMPE GOVRE DRDY
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
EOC15 EOC14 EOC13 EOC12 EOC11 EOC10 EOC9 EOC8
76543210
EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0
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43.7.10 ADC Interrupt Disable Register
Name: ADC_IDR
Address: 0x400C0028
Access: Write-only
• EOCx: End of Conversion Interrupt Disable x
• DRDY: Data Ready Interrupt Disable
• GOVRE: General Overrun Error Interrupt Disable
• COMPE: Comparison Event Interrupt Disable
• ENDRX: End of Receive Buffer Interrupt Disable
• RXBUFF: Receive Buffer Full Interrupt Disable
0 = No effect.
1 = Disables the corresponding interrupt.
31 30 29 28 27 26 25 24
– – – RXBUFF ENDRX COMPE GOVRE DRDY
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
EOC15 EOC14 EOC13 EOC12 EOC11 EOC10 EOC9 EOC8
76543210
EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0
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43.7.11 ADC Interrupt Mask Register
Name: ADC_IMR
Address: 0x400C002C
Access: Read-only
• EOCx: End of Conversion Interrupt Mask x
• DRDY: Data Ready Interrupt Mask
• GOVRE: General Overrun Error Interrupt Mask
• COMPE: Comparison Event Interrupt Mask
• ENDRX: End of Receive Buffer Interrupt Mask
• RXBUFF: Receive Buffer Full Interrupt Mask
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
31 30 29 28 27 26 25 24
– – – RXBUFF ENDRX COMPE GOVRE DRDY
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
EOC15 EOC14 EOC13 EOC12 EOC11 EOC10 EOC9 EOC8
76543210
EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0
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43.7.12 ADC Interrupt Status Register
Name: ADC_ISR
Address: 0x400C0030
Access: Read-only
• EOCx: End of Conversion x
0 = Corresponding analog channel is disabled, or the conversion is not finished. This flag is cleared when reading the cor-
responding ADC_CDRx registers.
1 = Corresponding analog channel is enabled and conversion is complete.
• DRDY: Data Ready
0 = No data has been converted since the last read of ADC_LCDR.
1 = At least one data has been converted and is available in ADC_LCDR.
• GOVRE: General Overrun Error
0 = No General Overrun Error occurred since the last read of ADC_ISR.
1 = At least one General Overrun Error has occurred since the last read of ADC_ISR.
• COMPE: Comparison Error
0 = No Comparison Error since the last read of ADC_ISR.
1 = At least one Comparison Error has occurred since the last read of ADC_ISR.
• ENDRX: End of RX Buffer
0 = The Receive Counter Register has not reached 0 since the last write in ADC_RCR or ADC_RNCR.
1 = The Receive Counter Register has reached 0 since the last write in ADC_RCR or ADC_RNCR.
• RXBUFF: RX Buffer Full
0 = ADC_RCR or ADC_RNCR have a value other than 0.
1 = Both ADC_RCR and ADC_RNCR have a value of 0.
31 30 29 28 27 26 25 24
– – – RXBUFF ENDRX COMPE GOVRE DRDY
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
EOC15 EOC14 EOC13 EOC12 EOC11 EOC10 EOC9 EOC8
76543210
EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0
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43.7.13 ADC Overrun Status Register
Name: ADC_OVER
Address: 0x400C003C
Access: Read-only
• OVREx: Overrun Error x
0 = No overrun error on the corresponding channel since the last read of ADC_OVER.
1 = There has been an overrun error on the corresponding channel since the last read of ADC_OVER.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
OVRE15 OVRE14 OVRE13 OVRE12 OVRE11 OVRE10 OVRE9 OVRE8
76543210
OVRE7 OVRE6 OVRE5 OVRE4 OVRE3 OVRE2 OVRE1 OVRE0
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43.7.14 ADC Extended Mode Register
Name: ADC_EMR
Address: 0x400C0040
Access: Read-write
This register can only be written if the WPEN bit is cleared in “ADC Write Protect Mode Register” on page 1353.
• CMPMODE: Comparison Mode
• CMPSEL: Comparison Selected Channel
If CMPALL = 0: CMPSEL indicates which channel has to be compared.
If CMPALL = 1: No effect.
• CMPALL: Compare All Channels
0 = Only channel indicated in CMPSEL field is compared.
1 = All channels are compared.
• CMPFILTER: Compare Event Filtering
Number of consecutive compare events necessary to raise the flag = CMPFILTER+1
When programmed to 0, the flag rises as soon as an event occurs.
• TAG: TAG of ADC_LDCR register
0 = set CHNB to zero in ADC_LDCR.
1 = append the channel number to the conversion result in ADC_LDCR register.
31 30 29 28 27 26 25 24
–––––––TAG
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – CMPFILTER – – CMPALL –
76543210
CMPSEL – – CMPMODE
Value Name Description
0 LOW Generates an event when the converted data is lower than the low threshold of the window.
1 HIGH Generates an event when the converted data is higher than the high threshold of the window.
2 IN Generates an event when the converted data is in the comparison window.
3OUT Generates an event when the converted data is out of the comparison window.
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43.7.15 ADC Compare Window Register
Name: ADC_CWR
Address: 0x400C0044
Access: Read-write
This register can only be written if the WPEN bit is cleared in “ADC Write Protect Mode Register” on page 1353.
• LOWTHRES: Low Threshold
Low threshold associated to compare settings of ADC_EMR register.
• HIGHTHRES: High Threshold
High threshold associated to compare settings of ADC_EMR register.
31 30 29 28 27 26 25 24
–––– HIGHTHRES
23 22 21 20 19 18 17 16
HIGHTHRES
15 14 13 12 11 10 9 8
–––– LOWTHRES
76543210
LOWTHRES
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43.7.16 ADC Channel Gain Register
Name: ADC_CGR
Address: 0x400C0048
Access: Read-write
This register can only be written if the WPEN bit is cleared in “ADC Write Protect Mode Register” on page 1353.
• GAINx: Gain for channel x
Gain applied on input of analog-to-digital converter.
The DIFFx mentioned in this table is described in the following register, ADC_COR.
31 30 29 28 27 26 25 24
GAIN15 GAIN14 GAIN13 GAIN12
23 22 21 20 19 18 17 16
GAIN11 GAIN10 GAIN9 GAIN8
15 14 13 12 11 10 9 8
GAIN7 GAIN6 GAIN5 GAIN4
76543210
GAIN3 GAIN2 GAIN1 GAIN0
GAINx Gain applied when DIFFx = 0 Gain applied when DIFFx = 1
001 0.5
011 1
102 2
114 2
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43.7.17 ADC Channel Offset Register
Name: ADC_COR
Address: 0x400C004C
Access: Read-write
This register can only be written if the WPEN bit is cleared in “ADC Write Protect Mode Register” on page 1353.
• OFFx: Offset for channel x
0 = No Offset.
1 = center the analog signal on Vrefin/2 before the gain scaling. The Offset applied is: (G-1)Vrefin/2
where G is the gain applied (see description of ADC_CGR register).
• DIFFx: Differential inputs for channel x
0 = Single Ended Mode.
1 = Fully Differential Mode.
31 30 29 28 27 26 25 24
DIFF15 DIFF14 DIFF13 DIFF12 DIFF11 DIFF10 DIFF9 DIFF8
23 22 21 20 19 18 17 16
DIFF7 DIFF6 DIFF5 DIFF4 DIFF3 DIFF2 DIFF1 DIFF0
15 14 13 12 11 10 9 8
OFF15 OFF14 OFF13 OFF12 OFF11 OFF10 OFF9 OFF8
76543210
OFF7 OFF6 OFF5 OFF4 OFF3 OFF2 OFF1 OFF0
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43.7.18 ADC Channel Data Register
Name: ADC_CDRx [x=0..15]
Address: 0x400C0050
Access: Read-only
• DATA: Converted Data
The analog-to-digital conversion data is placed into this register at the end of a conversion and remains until a new conver-
sion is completed. The Convert Data Register (CDR) is only loaded if the corresponding analog channel is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––– DATA
76543210
DATA
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43.7.19 ADC Analog Control Register
Name: ADC_ACR
Address: 0x400C0094
Access: Read-only
This register can only be written if the WPEN bit is cleared in “ADC Write Protect Mode Register” on page 1353.
• TSON: Temperature Sensor On
0 = temperature sensor is off.
1 = temperature sensor is on.
• IBCTL: ADC Bias Current Control
Allows to adapt performance versus power consumption. (See the product electrical characteristics for further details.)
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––– IBCTL
76543210
–––TSON––––
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43.7.20 ADC Write Protect Mode Register
Name: ADC_WPMR
Address: 0x400C00E4
Access: Read-write
• WPEN: Write Protect Enable
0 = Disables the Write Protect if WPKEY corresponds to 0x414443 (“ADC” in ASCII).
1 = Enables the Write Protect if WPKEY corresponds to 0x414443 (“ADC” in ASCII).
Protects the registers:
“ADC Mode Register” on page 1333
“ADC Channel Sequence 1 Register” on page 1336
“ADC Channel Sequence 2 Register” on page 1337
“ADC Channel Enable Register” on page 1338
“ADC Channel Disable Register” on page 1339
“ADC Extended Mode Register” on page 1347
“ADC Compare Window Register” on page 1348
“ADC Channel Gain Register” on page 1349
“ADC Channel Offset Register” on page 1350
“ADC Analog Control Register” on page 1352
• WPKEY: Write Protect KEY
Should be written at value 0x414443 (“ADC” in ASCII). Writing any other value in this field aborts the write operation of the
WPEN bit. Always reads as 0.
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
–––––––WPEN
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43.7.21 ADC Write Protect Status Register
Name: ADC_WPSR
Address: 0x400C00E8
Access: Read-only
• WPVS: Write Protect Violation Status
0 = No Write Protect Violation has occurred since the last read of the ADC_WPSR register.
1 = A Write Protect Violation has occurred since the last read of the ADC_WPSR register. If this violation is an unauthor-
ized attempt to write a protected register, the associated violation is reported into field WPVSRC.
• WPVSRC: Write Protect Violation Source
When WPVS is active, this field indicates the write-protected register (through address offset or code) in which a write
access has been attempted.
Reading ADC_WPSR automatically clears all fields.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
WPVSRC
15 14 13 12 11 10 9 8
WPVSRC
76543210
–––––––WPVS
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44. Digital-to-Analog Converter Controller (DACC)
44.1 Description
The Digital-to-Analog Converter Controller (DACC) offers up to 2 analog outputs, making it possible for the digital-
to-analog conversion to drive up to 2 independent analog lines.
The DACC supports 12-bit resolution. Data to be converted are sent in a common register for all channels.
External triggers or free running mode are configurable.
The DACC integrates a Sleep Mode and connects with a PDC channel. These features reduce both power
consumption and processor intervention.
The user can configure DACC timings, such as Startup Time and Refresh Period.
44.2 Embedded Characteristics
Up to Four Independent Analog Outputs
12-bit Resolution
Individual Enable and Disable of Each Analog Channel
Hardware Trigger
̶External Trigger Pins
PDC Support
Possibility of DACC Timings and Current Configuration
Sleep Mode
̶Automatic Wake-up on Trigger and Back-to-Sleep Mode after Conversions of all Enabled Channels
Internal FIFO
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44.3 Block Diagram
Figure 44-1. Digital-to-Analog Converter Controller Block Diagram
44.4 Signal Description
Table 44-1. DACC Pin Description
Pin Name Description
DAC0 - DAC1 Analog output channels
DATRG External triggers
DAC0 DAC1
AHB
Analog Cell
DAC Controller
Control
Logic Interrupt
Controller
PDC
Peripheral Bridge
APB
User
Interface
Sample & Hold
Sample & Hold
Trigger
Selection
DATRG
DAC Core
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44.5 Product Dependencies
44.5.1 Power Management
The DACC becomes active as soon as a conversion is requested and at least one channel is enabled. The DACC
is automatically deactivated when no channels are enabled.
For power saving options see Section 44.6.6 ”Sleep Mode”.
44.5.2 Interrupt Sources
The DACC interrupt line is connected on one of the internal sources of the interrupt controller. Using the DACC
interrupt requires the interrupt controller to be programmed first.
44.5.3 Conversion Performances
For performance and electrical characteristics of the DACC, see the product DC Characteristics section.
Table 44-2. Peripheral IDs
Instance ID
DACC 38
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44.6 Functional Description
44.6.1 Digital-to-Analog Conversion
The DACC uses the master clock (MCK) divided by two to perform conversions. This clock is named DACC Clock.
Once a conversion starts the DACC takes 25 clock periods to provide the analog result on the selected analog
output.
44.6.2 Conversion Results
When a conversion is completed, the resulting analog value is available at the selected DACC channel output and
the EOC bit in the DACC Interrupt Status Register, is set.
Reading the DACC_ISR register clears the EOC bit.
44.6.3 Conversion Triggers
In free running mode, conversion starts as soon as at least one channel is enabled and data is written in the DACC
Conversion Data Register, then 25 DACC Clock periods later, the converted data is available at the corresponding
analog output as stated above.
In external trigger mode, the conversion waits for a rising edge on the selected trigger to begin.
Warning: Disabling the external trigger mode automatically sets the DACC in free running mode.
44.6.4 Conversion FIFO
A 4 half-word FIFO is used to handle the data to be converted.
As long as the TXRDY flag in the DACC Interrupt Status Register is active the DAC Controller is ready to accept
conversion requests by writing data into DACC Conversion Data Register. Data which cannot be converted
immediately are stored in the DACC FIFO.
When the FIFO is full or the DACC is not ready to accept conversion requests, the TXRDY flag is inactive.
The WORD field of the DACC Mode Register allows the user to switch between half-word and word transfer for
writing into the FIFO.
In half-word transfer mode only the 16 LSB of DACC_CDR data are taken into account, DACC_CDR[15:0] is
stored into the FIFO.
DACC_CDR[11:0] field is used as data and the DACC_CDR[15:12] bits are used for channel selection if the TAG
field is set in DACC_MR register.
In word transfer mode each time the DACC_CDR register is written 2 data items are stored in the FIFO. The first
data item sampled for conversion is DACC_CDR[15:0] and the second DACC_CDR[31:16].
Fields DACC_CDR[15:12] and DACC_CDR[31:28] are used for channel selection if the TAG field is set in
DACC_MR register.
Warning: Writing in the DACC_CDR register while TXRDY flag is inactive will corrupt FIFO data.
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44.6.5 Channel Selection
There are two means by which to select the channel to perform data conversion.
By default, to select the channel where to convert the data, is to use the USER_SEL field of the DACC Mode
Register. Data requests will merely be converted to the channel selected with the USER_SEL field.
A more flexible option to select the channel for the data to be converted to is to use the tag mode, setting the
TAG field of the DACC Mode Register to 1. In this mode the 2 bits, DACC_CDR[13:12] which are otherwise
unused, are employed to select the channel in the same way as with the USER_SEL field. Finally, if the
WORD field is set, the 2 bits, DACC_CDR[13:12] are used for channel selection of the first data and the 2
bits, DACC_CDR[29:28] for channel selection of the second data.
44.6.6 Sleep Mode
The DACC Sleep Mode maximizes power saving by automatically deactivating the DACC when it is not being used
for conversions.
When a start conversion request occurs, the DACC is automatically activated. As the analog cell requires a start-
up time, the logic waits during this time and starts the conversion on the selected channel. When all conversion
requests are complete, the DACC is deactivated until the next request for conversion.
A fast wake-up mode is available in the DACC Mode Register as a compromise between power saving strategy
and responsiveness. Setting the FASTW bit to 1 enables the fast wake-up mode. In fast wake-up mode the DACC
is not fully deactivated while no conversion is requested, thereby providing less power saving but faster wake-up (4
times faster).
44.6.7 DACC Timings
The DACC startup time must be defined by the user in the STARTUP field of the DACC Mode Register.
This startup time differs depending of the use of the fast wake-up mode along with sleep mode, in this case the
user must set the STARTUP time corresponding to the fast wake up and not the standard startup time.
A max speed mode is available by setting the MAXS bit to 1 in the DACC_MR register. Using this mode, the DAC
Controller no longer waits to sample the end of cycle signal coming from the DACC block to start the next
conversion and uses an internal counter instead. This mode gains 2 DACC Clock periods between each
consecutive conversion.
Warning: Using this mode, the EOC interrupt of the DACC_IER register should not be used as it is 2 DACC Clock
periods late.
After 20 µs the analog voltage resulting from the converted data will start decreasing, therefore it is necessary to
refresh the channel on a regular basis to prevent this voltage loss. This is the purpose of the REFRESH field in the
DACC Mode Register where the user will define the period for the analog channels to be refreshed.
Warning: A REFRESH PERIOD field set to 0 will disable the refresh function of the DACC channels.
_|_|_|_|_|—|_|—L _____ FL _____ J_|_|_|_|—L _____ J_|_l_|_l_|_l_ T X _l T T X X AtmeL
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Figure 44-2. Conversion Sequence
MCK
Write USER_SEL
field
Selected Channel
Write DACC_CDR
DAC Channel 0
Output
DAC Channel 1
Output
EOC
Read DACC_ISR
Select Channel 0
Channel 0 Channel 1
Data 0 Data 1 Data 2
Data 0 Data 1
Data 2
Select Channel 1
None
TXRDY CDR FIFO not full
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44.6.8 Write Protection Registers
In order to provide security to the DACC, a write protection system has been implemented.
The write protection mode prevents the writing of certain registers. When this mode is enabled and one of the
protected registers is written, an error is generated in the DACC Write Protect Status Register and the register
write request is canceled. When a write protection error occurs, the WPROTERR flag is set and the address of the
corresponding canceled register write is available in the WPROTADRR field of the DACC Write Protect Status
Register.
Due to the nature of the write protection feature, enabling and disabling the write protection mode requires the use
of a security code. Thus when enabling or disabling the write protection mode the WPKEY field of the DACC Write
Protect Mode Register must be filled with the “DAC” ASCII code (corresponding to 0x444143) otherwise the
register write is canceled.
The protected registers are:
DACC Mode Register
DACC Channel Enable Register
DACC Channel Disable Register
DACC Analog Current Register
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44.7 Analog Converter Controller (DACC) User Interface
Table 44-3. Register Mapping
Offset Register Name Access Reset
0x00 Control Register DACC_CR Write-only –
0x04 Mode Register DACC_MR Read-write 0x00000000
0x08 Reserved – – –
0x0C Reserved – – –
0x10 Channel Enable Register DACC_CHER Write-only –
0x14 Channel Disable Register DACC_CHDR Write-only –
0x18 Channel Status Register DACC_CHSR Read-only 0x00000000
0x1C Reserved – – –
0x20 Conversion Data Register DACC_CDR Write-only 0x00000000
0x24 Interrupt Enable Register DACC_IER Write-only –
0x28 Interrupt Disable Register DACC_IDR Write-only –
0x2C Interrupt Mask Register DACC_IMR Read-only 0x00000000
0x30 Interrupt Status Register DACC_ISR Read-only 0x00000000
0x94 Analog Current Register DACC_ACR Read-write 0x00000000
0xE4 Write Protect Mode register DACC_WPMR Read-write 0x00000000
0xE8 Write Protect Status register DACC_WPSR Read-only 0x00000000
... ... ... ... ...
0xEC - 0xFC Reserved – – –
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44.7.1 DACC Control Register
Name: DACC_CR
Address: 0x400C8000
Access: Write-only
• SWRST: Software Reset
0: No effect.
1: Resets the DACC simulating a hardware reset.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––SWRST
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44.7.2 DACC Mode Register
Name: DACC_MR
Address: 0x400C8004
Access: Read-write
This register can only be written if the WPEN bit is cleared in DACC Write Protect Mode Register.
• TRGEN: Trigger Enable
• TRGSEL: Trigger Selection
• WORD: Word Transfer
31 30 29 28 27 26 25 24
– – STARTUP
23 22 21 20 19 18 17 16
– – MAXS TAG – – USER_SEL
15 14 13 12 11 10 9 8
REFRESH
76543210
– FASTWKUP SLEEP WORD TRGSEL TRGEN
Value Name Description
0 DIS External trigger mode disabled. DACC in free running mode.
1 EN External trigger mode enabled.
TRGSEL Selected TRGSEL
000External trigger
001TIO Output of the Timer Counter Channel 0
010TIO Output of the Timer Counter Channel 1
011TIO Output of the Timer Counter Channel 2
100PWM Event Line 0
101PWM Event Line 1
110Reserved
111Reserved
Value Name Description
0 HALF Half-Word transfer
1 WORD Word Transfer
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• SLEEP: Sleep Mode
0: Normal Mode: The DAC Core and reference voltage circuitry are kept ON between conversions.
After reset, the DAC is in normal mode but with the voltage reference and the DAC core off. For the first conversion, a
startup time must be defined in the STARTUP field. Note that in this mode, STARTUP time is only required once, at start
up.
1: Sleep Mode: The DAC Core and reference voltage circuitry are OFF between conversions.
• FASTWKUP: Fast Wake up Mode
0: Normal Sleep Mode: The sleep mode is defined by the SLEEP bit.
1: Fast Wake Up Sleep Mode: The voltage reference is ON between conversions and DAC Core is OFF.
• REFRESH: Refresh Period
Refresh Period = 1024*REFRESH/DACC Clock
• USER_SEL: User Channel Selection
• TAG: Tag Selection Mode
• MAXS: Max Speed Mode
SLEEP Selected Mode
0 Normal Mode
1 Sleep Mode
FASTWKUP Selected Mode
0 Normal Sleep Mode
1 Fast Wake up Sleep Mode
Value Name Description
0 CHANNEL0 Channel 0
1 CHANNEL1 Channel 1
2 Reserved
3 Reserved
Value Name Description
0DIS
Tag selection mode disabled. Using USER_SEL to select
the channel for the conversion.
1 EN Tag selection mode enabled
MAX SPEED Selected Mode
0 Normal Mode
1 Max Speed Mode enabled
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• STARTUP: Startup Time Selection
Note: Refer to the product DAC electrical characteristics section for Startup Time value.
Value Name Description Value Name Description
0 0 0 periods of DACClock 32 2048 2048 periods of DACClock
1 8 8 periods of DACClock 33 2112 2112 periods of DACClock
2 16 16 periods of DACClock 34 2176 2176 periods of DACClock
3 24 24 periods of DACClock 35 2240 2240 periods of DACClock
4 64 64 periods of DACClock 36 2304 2304 periods of DACClock
5 80 80 periods of DACClock 37 2368 2368 periods of DACClock
6 96 96 periods of DACClock 38 2432 2432 periods of DACClock
7 112 112 periods of DACClock 39 2496 2496 periods of DACClock
8 512 512 periods of DACClock 40 2560 2560 periods of DACClock
9 576 576 periods of DACClock 41 2624 2624 periods of DACClock
10 640 640 periods of DACClock 42 2688 2688 periods of DACClock
11 704 704 periods of DACClock 43 2752 2752 periods of DACClock
12 768 768 periods of DACClock 44 2816 2816 periods of DACClock
13 832 832 periods of DACClock 45 2880 2880 periods of DACClock
14 896 896 periods of DACClock 46 2944 2944 periods of DACClock
15 960 960 periods of DACClock 47 3008 3008 periods of DACClock
16 1024 1024 periods of DACClock 48 3072 3072 periods of DACClock
17 1088 1088 periods of DACClock 49 3136 3136 periods of DACClock
18 1152 1152 periods of DACClock 50 3200 3200 periods of DACClock
19 1216 1216 periods of DACClock 51 3264 3264 periods of DACClock
20 1280 1280 periods of DACClock 52 3328 3328 periods of DACClock
21 1344 1344 periods of DACClock 53 3392 3392 periods of DACClock
22 1408 1408 periods of DACClock 54 3456 3456 periods of DACClock
23 1472 1472 periods of DACClock 55 3520 3520 periods of DACClock
24 1536 1536 periods of DACClock 56 3584 3584 periods of DACClock
25 1600 1600 periods of DACClock 57 3648 3648 periods of DACClock
26 1664 1664 periods of DACClock 58 3712 3712 periods of DACClock
27 1728 1728 periods of DACClock 59 3776 3776 periods of DACClock
28 1792 1792 periods of DACClock 60 3840 3840 periods of DACClock
29 1856 1856 periods of DACClock 61 3904 3904 periods of DACClock
30 1920 1920 periods of DACClock 62 3968 3968 periods of DACClock
31 1984 1984 periods of DACClock 63 4032 4032 periods of DACClock
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44.7.3 DACC Channel Enable Register
Name: DACC_CHER
Address: 0x400C8010
Access: Write-only
This register can only be written if the WPEN bit is cleared in DACC Write Protect Mode Register.
• CHx: Channel x Enable
0: No effect.
1: Enables the corresponding channel.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––– CH1CH0
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44.7.4 DACC Channel Disable Register
Name: DACC_CHDR
Address: 0x400C8014
Access: Write-only
This register can only be written if the WPEN bit is cleared in DACC Write Protect Mode Register.
• CHx: Channel x Disable
0: No effect.
1: Disables the corresponding channel.
Warning: If the corresponding channel is disabled during a conversion or if it is disabled then re-enabled during a conver-
sion, its associated analog value and its corresponding EOC flags in DACC_ISR are unpredictable.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––– CH1CH0
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44.7.5 DACC Channel Status Register
Name: DACC_CHSR
Address: 0x400C8018
Access: Read-only
• CHx: Channel x Status
0: Corresponding channel is disabled.
1: Corresponding channel is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––– CH1CH0
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44.7.6 DACC Conversion Data Register
Name: DACC_CDR
Address: 0x400C8020
Access: Write-only
• DATA: Data to Convert
When the WORD bit in DACC_MR register is cleared, only DATA[15:0] is used else DATA[31:0] is used to write 2 data to
be converted.
31 30 29 28 27 26 25 24
DATA
23 22 21 20 19 18 17 16
DATA
15 14 13 12 11 10 9 8
DATA
76543210
DATA
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44.7.7 DACC Interrupt Enable Register
Name: DACC_IER
Address: 0x400C8024
Access: Write-only
• TXRDY: Transmit Ready Interrupt Enable
• EOC: End of Conversion Interrupt Enable
• ENDTX: End of Transmit Buffer Interrupt Enable
• TXBUFE: Transmit Buffer Empty Interrupt Enable
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––TXBUFEENDTXEOCTXRDY
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44.7.8 DACC Interrupt Disable Register
Name: DACC_IDR
Address: 0x400C8028
Access: Write-only
• TXRDY: Transmit Ready Interrupt Disable.
• EOC: End of Conversion Interrupt Disable
• ENDTX: End of Transmit Buffer Interrupt Disable
• TXBUFE: Transmit Buffer Empty Interrupt Disable
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––TXBUFEENDTXEOCTXRDY
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44.7.9 DACC Interrupt Mask Register
Name: DACC_IMR
Address: 0x400C802C
Access: Read-only
• TXRDY: Transmit Ready Interrupt Mask
• EOC: End of Conversion Interrupt Mask
• ENDTX: End of Transmit Buffer Interrupt Mask
• TXBUFE: Transmit Buffer Empty Interrupt Mask
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––TXBUFEENDTXEOCTXRDY
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44.7.10 DACC Interrupt Status Register
Name: DACC_ISR
Address: 0x400C8030
Access: Read-only
• TXRDY: Transmit Ready Interrupt Flag
0: DACC is not ready to accept new conversion requests.
1: DACC is ready to accept new conversion requests.
• EOC: End of Conversion Interrupt Flag
0: no conversion has been performed since the last DACC_ISR read.
1: at least one conversion has been performed since the last DACC_ISR read.
• ENDTX: End of DMA Interrupt Flag
0: the Transmit Counter Register has not reached 0 since the last write in DACC_TCR or DACC_TNCR.
1: the Transmit Counter Register has reached 0 since the last write in DACC _TCR or DACC_TNCR
• TXBUFE: Transmit Buffer Empty
0: the Transmit Counter Register has not reached 0 since the last write in DACC_TCR or DACC_TNCR.
1: the Transmit Counter Register has reached 0 since the last write in DACC _TCR or DACC_TNCR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––TXBUFEENDTXEOCTXRDY
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44.7.11 DACC Analog Current Register
Name: DACC_ACR
Address: 0x400C8094
Access: Read-write
This register can only be written if the WPEN bit is cleared in DACC Write Protect Mode Register.
• IBCTLCHx: Analog Output Current Control
Allows to adapt the slew rate of the analog output. (See the product electrical characteristics for further details.)
• IBCTLDACCORE: Bias Current Control for DAC Core
Allows to adapt performance versus power consumption. (See the product electrical characteristics for further details.)
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––IBCTLDACCORE
76543210
–––– IBCTLCH1 IBCTLCH0
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44.7.12 DACC Write Protect Mode Register
Name: DACC_WPMR
Address: 0x400C80E4
Access: Read-write
• WPEN: Write Protect Enable
0: Disables the Write Protect if WPKEY corresponds to 0x444143 (“DAC” in ASCII).
1: Enables the Write Protect if WPKEY corresponds to 0x444143 (“DAC” in ASCII).
The protected registers are:
DACC Mode Register
DACC Channel Enable Register
DACC Channel Disable Register
DACC Analog Current Register
• WPKEY: Write Protect KEY
This security code is needed to set/reset the WPROT bit value (see Section ”” for details).
Must be filled with “DAC” ASCII code.
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
–––––––WPEN
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44.7.13 DACC Write Protect Status Register
Name: DACC_WPSR
Address: 0x400C80E8
Access: Read-only
• WPROTADDR: Write protection error address
Indicates the address of the register write request which generated the error.
• WPROTERR: Write protection error
Indicates a write protection error.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
WPROTADDR
76543210
–––––––WPROTERR
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45. Electrical Characteristics
45.1 Absolute Maximum Ratings
Table 45-1. Absolute Maximum Ratings*
Operating Temperature (Industrial).....................-40°C to +85°C *NOTICE: Stresses beyond those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of the
device at these or other conditions beyond those indi-
cated in the operational sections of this specification is
not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device
reliability.
Storage Temperature........................................-60°C to +150°C
Voltage on Input Pins
with Respect to Ground (except VBUS)...............-0.3V to +4.0V
Voltage on VBUS Pin
with Respect to Ground........................................-0.3V to +6.0V
Maximum Operating Voltage
(VDDCORE)........................................................................2.0V
Maximum Operating Voltage
(VDDIO)...............................................................................4.0V
Total DC Output Current on all I/O lines
100-lead LQFP................................................................100 mA
144-lead LQFP................................................................130 mA
100-ball TFBGA..............................................................150 mA
144-ball LFBGA..............................................................150 mA
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45.2 DC Characteristics
The following characteristics are applicable to the operating temperature range TA = -40°C to 85°C, unless
otherwise specified.
Table 45-2. DC Characteristics
Symbol Parameter Conditions Min Typ Max Unit
VDDCORE DC Supply Core 1.62 1.8 1.95 V
VDDIO DC Supply I/Os 1.62 3.3 3.6 V
VDDBU Backup I/O Lines Power
Supply 1.62 3.6 V
VDDUTMII USB UTMI+ Interface
Power Supply 3.0 3.6 V
VDDPLL PLL A, UPLL and Main
Oscillator Supply 1.62 1.95 V
VDDANA ADC Analog Power
Supply (1) (1) V
VIL Input Low-level Voltage PIOA/B/C/D/E/F[0–31] -0.3 0.3 × VDDIO V
VIH Input High-level Voltage PIOA/B/C/D/E/F[0–31] 0.7 × VDDIO VDDIO + 0.3V V
VOH Output High-level Voltage
PIOA/B/C/D/E/F[0–31]
IOH ~ 0
IOH > 0 (See IOH details below)
VDDIO - 0.2V
VDDIO - 0.4V
V
VOL Output Low-level Voltage
PIOA/B/C/D/E/F[0–31]
IOH ~ 0
IOH > 0 (See IOL details below)
0.2
0.4
V
Vhys Hysteresis Voltage
PIOA/B/C/D/E/F[0–31]
except PA0, PA9, PA26, PA29, PA30, PA31,
PB14, PB22, PC[2–9], PC[15–24], PD[10–30],
PE[0–4], PE15, PE17, PE19, PE21, PE23, PE25,
PE29
150 500 mV
ERASE, TST, FWUP, JTAGSEL 230 700 mV
IOH Source Current
1.62V < VDDIO < 1.95V; VOH = VDDIO - 0.4
- Group 1(2)
- Group 2(3)
-8
-3
mA
3.0V < VDDIO < 3.6V; VOH = VDDIO - 0.4
- Group 1(2)
- Group 2(3)
-15
-3
1.62V < VDDIO < 3.6V; VOH = VDDIO - 0.4
- NRST, TDO -2
Relaxed Mode:
3.0V < VDDIO < 3.6V; VOH = 2.2V
- Group 1(2)
- Group 2(3)
-24
-9
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Notes: 1. Refer to Section 45.7 “12-bit ADC Characteristics” and Section 45.9 “12-bit DAC Characteristics”
2. PA0, PA7, PA9, PA[14–15], PA[18–19], PA[25–31], PB[0–3], PB8, PB[10–11], PB14, PB[22–24], PC[0–30], PD[0–30], PE[0–
9], PE15, PE[17–21], PE23, PE25, PF[0–2]
3. PA[1–6], PA8, PA[10–13], PA[16–17], PA[20–24], PB[4–7], PB9, PB[12–13], PB[15–21], PB[25–31], PE[10–14], PE16,
PE22, PE24, PE26, PF[3–5]
4. FWUP, JTAGSEL, NRSTB, ERASE, TST
IOL Sink Current
1.62V < VDDIO < 1.95V; VOL = 0.4V
- Group 1(2)
- Group 2(3)
8
4
mA
3.0V < VDDIO < 3.6V; VOL = 0.4V
- Group 1(2)
- Group 2(3)
9
6
1.62V < VDDIO < 3.6V; VOL = 0.4V
- NRST, TDO 2
Relaxed Mode:
3.0V < VDDIO < 3.6V; VOL = 0.6V
- Group 1(2)
- Group 2(3)
14
9
IIL_lkg Input Low Leakage
Current
VDDIO powered pins(3)
No pull-up or pull-down; VIN = GND; VDDIO Max.
(Typ: TA = 25°C, Max: TA = 85°C) 530nA
VDDBU powered pins(4)
No pull-up or pull-down; VIN = GND; VDDBU Max.
(Typ: TA = 25°C, Max: TA = 85°C) 1µA
IIH_lkg Input High Leakage
Current
VDDIO powered pins(3)
No pull-up or pull-down; VIN = VDD; VDDIO Max.
(Typ: TA = 25°C, Max: TA = 85°C) 218nA
VDDBU powered pins(4)
No pull-up or pull-down; VIN = VDD; VDDBU Max.
(Typ: TA = 25°C, Max: TA = 85°C) 1µA
RPULLUP Pull-up Resistor
PA0–PA31, PB0–PB31, PC0–PC30, PD0–PD30,
PE0–PE31, PF0–PF5 50 100 150 kΩ
NRSTB 10 20 kΩ
RPULLDOWN Pull-down Resistor TST, ERASE, JTAGSEL 10 20 kΩ
RODT On-die Series Termination
Resistor PA0–PA31, PB0–PB31, PC0–PC30, PD0–PD30,
PE0–PE31, PF0–PF5 36 Ω
Table 45-2. DC Characteristics (Continued)
Symbol Parameter Conditions Min Typ Max Unit
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Notes: 1. A 10 µF or higher ceramic capacitor must be connected between VDDIN and the closest GND pin of the device.
This large decoupling capacitor is mandatory to reduce startup current, improving transient response and noise rejection.
2. To ensure stability, an external 4.7 µF output capacitor, CDOUT must be connected between the VDDOUT and the closest
GND pin of the device. The ESR (Equivalent Series Resistance) of the capacitor must be in the range 0.5–10 Ω.
Solid tantalum, and multilayer ceramic capacitors are all suitable as output capacitor.
A 100 nF bypass capacitor between VDDOUT and the closest GND pin of the device decreases output noise and improves
the load transient response.
3. Defined as the current needed to charge external bypass/decoupling capacitor network.
Table 45-3. 1.8V Voltage Regulator Characteristics
Symbol Parameter Conditions Min Typ Max Unit
VDDIN DC Input Voltage Range 1.8 3.3 3.6 V
VDDOUT DC Output Voltage Normal Mode 1.8 V
Standby Mode 0
VO(accuracy) Output Voltage Accuracy ILOAD = 0.5–150 mA -3 3 %
ILOAD Maximum DC Output Current VDDIN > 2.2V 150 mA
VDDIN ≤ 2.2V 60
ILOAD-START Maximum Peak Current
during startup (3) 300 mA
VDROPOUT Dropout Voltage VDDIN = 1.8V
ILOAD = 60 mA 120 240 mV
VLINE Line Regulation VDDIN from 2.7V to 3.6V
ILOAD MAX 20 50 mV
VLINE-TR Transient Line regulation
VDDIN from 2.7V to 3.6V
tr = tf = 5 µs
ILOAD Max
CDOUT = 4.7 µF
50 100 mV
VLOAD Load Regulation VDDIN ≥ 2.2V
ILOAD = 10% to 90% MAX 20 50
mV
VLOAD-TR Transient Load Regulation
VDDIN ≥ 2.2V
ILOAD = 10% to 90% MAX
tr = tf = 5 µs
CDOUT = 4.7 µF
50 100
IQQuiescent Current
Normal Mode @ ILOAD = 0 mA 7 10
µANormal Mode @ ILOAD = 150 mA 700 1200
Standby Mode 1
CDIN Input Decoupling Capacitor (1) 10 µF
CDOUT Output Decoupling Capacitor (2) 4.7 µF
ESR 0.5 10 Ω
ton Turn on Time
CDOUT = 4.7 µF
VDDOUT reaches VT+ (core power brownout detector
supply rising threshold) 120 250
µs
CDOUT = 4.7 µF
VDDOUT reaches 1.8V (± 3%) 200 400
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Note: 1. The product is guaranteed to be functional at VT-
Figure 45-1. Core Brownout Output Waveform
Table 45-4. Core Power Supply Brownout Detector Characteristics
Symbol Parameter Conditions Min Typ Max Unit
VT- Supply Falling Threshold(1) 1.52 1.55 1.58 V
Vhys- Hysteresis VT- 25 38 mV
VT+ Supply Rising Threshold 1.35 1.50 1.59 V
tRST Reset Period 100 350 µs
Vhys+ Hysteresis VT+ 100 250 mV
IDDON Current Consumption on VDDCORE Brownout Detector enabled 18 µA
IDDOFF Brownout Detector disabled 200 nA
td- VT- detection propagation time VDDCORE = VT+ to (VT- - 100mV) 200 ns
td+ VT+ detection propagation time 100 200 350 µs
tSTART Startup Time From disabled state to enabled state 100 200 µs
t
VDDCORE
VT-
VT+
BOD OUTPUT
t
td+
td-
Table 45-5. VDDUTMI Supply Monitor
Symbol Parameter Conditions Min Typ Max Unit
VTSupply Monitor Threshold 16 selectable steps of 100mV 1.9 3.4 V
VT(accuracy) Threshold Level Accuracy -1.5 +1.5 %
Vhys Hysteresis 20 30 mV
IDDON Current Consumption on VDDCORE Enabled 18 28 µA
IDDOFF Disabled 1
tSTART Startup Time From disabled state to enabled state 140 µs
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Figure 45-2. VDDUTMI Supply Monitor
Table 45-6. Threshold Selection
Digital Code Threshold Min (V) Threshold Typ (V) Threshold Max (V)
0000 1.881 1.9 1.919
0001 1.980 2.0 2.020
0010 2.079 2.1 2.121
0011 2.178 2.2 2.222
0100 2.277 2.3 2.323
0101 2.376 2.4 2.424
0110 2.475 2.5 2.525
0111 2.574 2.6 2.626
1000 2.673 2.7 2.727
1001 2.772 2.8 2.828
1010 2.871 2.9 2.929
1011 2.970 3.0 3.030
1100 3.069 3.1 3.131
1101 3.168 3.2 3.232
1110 3.267 3.3 3.333
1111 3.366 3.4 3.434
Table 45-7. Backup Power Supply Zero-Power-on Reset Characteristics
Symbol Parameter Conditions Min Typ Max Unit
VT+ Threshold Voltage Rising At startup 1.50 1.55 1.60 V
VT- Threshold Voltage Falling 1.40 1.45 1.50 V
tRST Reset Period 40 90 150 µs
VT
VT
+
Vhys
VDDIO
Reset
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Figure 45-3. Zero-Power-on Reset Characteristics
VT-
VT+
VDDIO
Reset
Table 45-8. DC Flash Characteristics
Symbol Parameter Conditions Typ Max Unit
IDD(standby) Standby current
@ 25°C onto VDDCORE = 1.8V
@ 85°C onto VDDCORE = 1.8V
@ 25°C onto VDDCORE = 1.95V
@ 85°C onto VDDCORE = 1.95V
< 1
14
< 1
15
1.5
40
1.8
50
µA
ICC Active current
128-bit Mode Read Access:
Maximum Read Frequency onto VDDCORE = 1.8V @ 25 °C
Maximum Read Frequency onto VDDCORE = 1.95V @ 25 °C
15
20
20
25
mA
64-bit Mode Read Access:
Maximum Read Frequency onto VDDCORE = 1.8V @ 25 °C
Maximum Read Frequency onto VDDCORE = 1.95V @ 25 °C
7.5
10
10
12.5
Write onto VDDCORE = 1.8V @ 25 °C
Write onto VDDCORE = 1.95V @ 25 °C
3.6
5.0
4.5
6.0
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45.3 Power Consumption
Power consumption of the device according to the different low-power mode capabilities (Backup, Wait,
Sleep) and Active mode
Power consumption on power supply in different modes: Backup, Wait, Sleep, and Active
Power consumption by peripheral: calculated as the difference in current measurement after having enabled
then disabled the corresponding clock
45.3.1 Backup Mode Current Consumption
The Backup mode configuration and measurements are defined as follows.
45.3.1.1 Backup Power Configuration
All power supplies OFF, except VDDBU
Supply Monitor on VDDUTMI is disabled
RTT and RTC not used
Embedded RC oscillator used
Wake-up pin FWUP = VDDBU
Current measurement on AMP1
Figure 45-4. Measurement Setup
Table 45-9. Power Consumption for Backup Mode
Conditions
VDDBU Consumption (AMP1) UnitVDDBU Temperature
3.3V
3.0V
2.5V
1.8V
25°C
3.1
2.8
2.3
1.7 µA
3.3V
3.0V
2.5V
1.8V
85°C
4.1
3.7
3.1
2.4
VDDBU
XOUT32
XIN32
VDDCORE,
VDDPLL
2.5, 3V, 3.3V
AMP1
VDDUTMI
VDDIO
VDDANA
““““ Emu—um a 9 whim;
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45.3.2 Wait and Sleep Mode Current Consumption
The Wait Mode and Sleep Mode configuration and measurements are defined below.
45.3.2.1 Sleep Mode
All power supplies are powered
Core clock OFF
Master Clock (MCK) running at various frequencies with PLLA or the fast RC oscillator
Fast startup through pins WKUP0–15
Current measurement on AMP1 (VDDOUT = VDDCORE + VDDPLL)
All peripheral clocks deactivated
Figure 45-5. Measurement Setup for Sleep Mode
VDDUTMI
VDDIO
VDDOUT
VDDCORE
VDDIN
Voltage
Regulator
VDDPLL
VDDANA
3.3V
AMP1
AMP2
VDDBU
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Figure 45-6. Current Consumption in Sleep Mode (AMP1) versus Master Clock Ranges (refer to Table 45-10)
Table 45-10. Sleep Mode Current Consumption versus Master Clock (MCK) Variation
Core Clock/MCK (MHz) AMP1 (IDDOUT) Consumption Unit
96 45.9 mA
84 29.4 mA
72 25.6 mA
60 21.7 mA
48 17.8 mA
36 14.5 mA
24 10.0 mA
18 8.6 mA
12 5.9 mA
84.92mA
43.52mA
22.37mA
11.31mA
0.5 0.78 mA
0.25 0.51 mA
0.125 0.38 mA
0.032 0.025 mA
0
2
4
6
8
10
12
14
16
18
20
22
24
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96
Processor and Peripheral Clocks in MHz
VDOUT (IDDCORE + IDDPLL) in mA
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45.3.2.2 Wait Mode
All power supplies are powered
Core Clock and Master Clock Stopped
Current measurement on AMP1, AMP2 and AMP3
All peripheral clocks deactivated
Figure 45-7. Measurement Setup for Wait Mode
Table 45-11 gives current consumption in typical conditions.
45.3.3 Active Mode Power Consumption
The Active Mode configuration and measurements are defined as follows:
VDDIO = VDDIN = VDDBU= VDDANA = VDUTMI = 3.3V for VDDCORE = 1.8V. VDDOUT not used for
VDDCORE = 1.62V
VDDCORE = 1.8V (internal voltage regulator used)
TA = 25°C
CoreMark Algorithm running from Flash Memory or SRAM
All peripheral clocks are deactivated.
Master Clock (MCK) running at various frequencies with PLLA or the fast RC oscillator
Current measurement on AMP1 ( VDDCORE ) and total current on AMP2
VDDUTMI
VDDIO
VDDOUT
VDDCORE
VDDIN
Voltage
Regulator
VDDPLL
VDDANA
3.3V
AMP1
AMP2
VDDBU
AMP3
Table 45-11. Typical Current Consumption in Wait Mode
Conditions
Consumption
Unit
VDDOUT
(AMP1) Total
(AMP2) Regulator and Core
(AMP3)
See Figure 45-7
@ 25°C
There is no activity on the I/Os of the device. 18.7 26.6 18.4 µA
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Figure 45-8. Active Mode Measurement Setup for VDDCORE at 1.8V
Figure 45-9. Active Mode Measurement Setup for VDDCORE at 1.62V
The following tables give Active mode current consumption in typical conditions.
VDDUTMI
VDDIO
VDDOUT
VDDCORE
VDDIN
Voltage
Regulator
VDDPLL
VDDANA
3.3V
AMP1
AMP2
VDDBU
VDDUTMI
VDDIO
VDDOUT
VDDCORE
VDDIN
Voltage
Regulator
VDDPLL
VDDANA
3.3V
AMP2
VDDBU
AMP1
1.62V
+++ AtmeL
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Note: 1. Flash Wait State (FWS) in EEFC_FMR adjusted versus Core Frequency
Figure 45-10. Active Power Consumption with VDDCORE @ 1.8V Running from Flash Memory or SRAM
Table 45-12. Active Power Consumption with VDDCORE @ 1.8V Running from Flash Memory or SRAM
Core Clock (MHz)
CoreMark
Unit
128-bit Flash Access(1) 64-bit Flash Access(1) SRAM
AMP1 AMP2 AMP1 AMP2 AMP1 AMP2
84 63.25 76.47 56.08 70.89 64.20 77.50
mA
72 57.63 70.83 51.71 66.86 49.40 62.80
60 53.66 65.48 47.79 62.72 41.80 55.20
48 46.55 57.57 44.70 55.65 34.20 47.60
32 35.44 47.75 31.71 45.21 24.30 38.00
24 29.59 42.44 26.11 39.19 18.90 32.60
12 16.55 32.02 16.26 29.51 11.10 24.90
8 13.40 28.80 12.66 27.51 8.70 22.70
4 10.68 25.46 10.66 24.11 6.10 20.20
2 12.88 23.58 11.53 22.56 6.40 19.50
1 7.87 21.37 7.21 20.13 4.60 17.70
0.5 5.939 18.239 5.321 17.63 3.4 16.7
0.25 3.72 16.27 3.54 15.92 2.90 16.10
0.125 3.12 15.41 2.89 15.24 2.70 15.90
0.032 2.17 14.43 2.17 14.60 2.20 15.50
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
0 10203040506070
IDDCORE (mA)
Core Clock -MHz)
128-bit Flash Access
64-bit Flash Access
SRAM
+++ AtmeL
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Notes: 1. Internal voltage regulator not used. VDDIO power consumption only.
2. Flash Wait State (FWS) in EEFC_FMR adjusted versus Core Frequency
Figure 45-11. Active Power Consumption with VDDCORE @ 1.62V Running from Flash Memory or SRAM
Table 45-13. Active Power Consumption with VDDCORE @ 1.62V Running from Flash Memory or SRAM
Core Clock (MHz)
CoreMark
Unit
128-bit Flash Access(2) 64-bit Flash Access(2) SRAM
AMP1 AMP2(1) AMP1 AMP2(1) AMP1 AMP2(1)
84 57.66 12.32 51.41 12.32 50.10 13.30
mA
72 51.46 12.32 46.18 12.25 43.60 13.30
60 45.98 12.27 41.97 12.30 36.80 13.30
48 40.90 12.28 36.08 12.34 30.10 13.30
32 31.45 12.32 27.94 12.26 21.30 13.30
24 24.73 12.39 22.32 12.30 16.50 13.30
12 15.32 12.37 14.72 12.30 9.60 13.30
8 12.16 12.28 11.65 12.32 7.50 13.30
4 8.79 12.30 8.01 12.29 5.20 13.30
2 10.57 12.32 9.57 12.28 5.50 13.30
1 6.83 12.30 6.05 12.27 3.70 13.30
0.5 4.59 12.26 4.30 12.31 2.80 13.30
0.25 3.42 12.25 3.12 12.29 2.40 13.30
0.125 2.57 12.30 2.47 12.27 2.20 13.30
0.032 1.74 12.35 1.73 12.34 1.80 13.30
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
0 10203040506070
IDDCORE (mA)
Core Clock (MHz)
128-bit Flash Access
64-bit Flash Access
SRAM
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45.3.4 Peripheral Power Consumption in Active Mode
Table 45-14. Power Consumption on VDDCORE(1)
Peripheral Consumption (Typ) Unit
UART 11.96 µA/MHz
PIOA 9.23 µA/MHz
PIOB 9.63 µA/MHz
PIOC 10.16 µA/MHz
PIOD 9.72 µA/MHz
PIOE 11.20 µA/MHz
PIOF 2.58 µA/MHz
USART0 31.15 µA/MHz
USART1 24.64 µA/MHz
USART2 25.31 µA/MHz
USART3 23.98 µA/MHz
HSMCI 30.54 µA/MHz
PWM 65.76 µA/MHz
SSC 15.00 µA/MHz
TWI0 17.03 µA/MHz
TWI1 17.29 µA/MHz
SPI0 3.55 µA/MHz
SPI1 2.56 µA/MHz
TC0 13.65 µA/MHz
TC1 8.41 µA/MHz
TC2 7.66 µA/MHz
TC3 12.08 µA/MHz
TC4 8.01 µA/MHz
TC5 7.58 µA/MHz
TC6 12.87 µA/MHz
TC7 7.91 µA/MHz
TC8 8.00 µA/MHz
ADC 22.62 µA/MHz
DAC 12.34 µA/MHz
DMAC 106.41 µA/MHz
SMC 81.54 µA/MHz
CAN0 53.87 µA/MHz
CAN1 54.75 µA/MHz
EMAC 150.35 µA/MHz
TRNG 2.87 µA/MHz
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Note: 1. VDDIO = 3.3V, VDDCORE = 1.80V, TA = 25°C
USB 73.63 µA/MHz
Table 45-14. Power Consumption on VDDCORE(1)
Peripheral Consumption (Typ) Unit
AtmeL
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45.4 Crystal Oscillators Characteristics
45.4.1 32 kHz RC Oscillator Characteristics
45.4.2 4/8/12 MHz RC Oscillators Characteristics
Notes: 1. Frequency range can be configured in the Supply Controller registers.
2. Not trimmed from factory.
3. After trimming from factory.
Table 45-15. 32 kHz RC Oscillator Characteristics
Symbol Parameter Conditions Min Typ Max Unit
fOSC RC Oscillator Frequency 20 32 44 kHz
Frequency Supply Dependency -3 3 %/V
Frequency Temperature Dependency Over temperature range -40 to 85 °C versus
TA 25°C -11 11 %
Duty Duty Cycle 45 50 55 %
tSTART Startup Time 100 µs
IDDON Current Consumption After startup time
Temp. range = -40 to 85 °C
Typical consumption at 2.2V supply and TA = 25°C 540 870 nA
Table 45-16. 4/8/12 MHz RC Oscillators Characteristics
Symbol Parameter Conditions Min Typ Max Unit
fOSC RC Oscillator Frequency Range (1) 412MHz
ACC44 MHz Total Accuracy -40°C < Temp < +85°C
4 MHz output selected (1)(2) ±35 %
ACC88 MHz Total Accuracy
-40°C < Temp < +85°C
8 MHz output selected (1)(3) ±3.5 %
-20°C < Temp < +85°C
8 MHz output selected (1)(3) ±2.5 %
0°C < Temp < +70°C
8 MHz output selected (1)(3) ±2 %
ACC12 12 MHz Total Accuracy
-40°C < Temp < +85°C
12 MHz output selected (1)(3) ±3.5 %
-20°C < Temp < +85°C
12 MHz output selected (1)(3) ±2.7 %
0°C < Temp < +70°C
12 MHz output selected (1)(3) ±2 %
Duty Duty Cycle 45 50 55 %
tSTART Startup Time 10 µs
IDDON Active Current Consumption
4MHz
8MHz
12 MHz
80
105
145
120
160
210
µA
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
45.4.3 32.768 kHz Crystal Oscillator Characteristics
Notes: 1. RS is the series resistor.
Figure 45-12. 32.768 kHz Crystal Oscillator Schematics
CLEXT = 2 × (Ccrystal – Cpara – CPCB)
where:
CPCB is the capacitance of the printed circuit board (PCB) track layout from the crystal to the SAM3 pin.
Table 45-17. 32.768 kHz Crystal Oscillator Characteristics
Symbol Parameter Conditions Min Typ Max Unit
fOSC Operating Frequency Normal mode with crystal 32.768 kHz
Vrip(VDDBU) Supply Ripple Voltage (on VDDBU) RMS value, 10 kHz to 10 MHz 30 mV
Duty Cycle 40 50 60 %
tSTART Startup Time
RS < 50 kΩ (1) Ccrystal = 12.5 pF
Ccrystal = 6 pF
900
300 ms
RS < 100 kΩ (1) Ccrystal = 12.5 pF
Ccrystal = 6 pF
1200
500
IDDON Current Consumption
RS < 50 kΩ (1) Ccrystal = 12.5 pF
Ccrystal = 6 pF
650
450
1400
1200 nA
RS < 100 kΩ (1) Ccrystal = 12.5 pF
Ccrystal = 6 pF
900
650
1600
1400
IDDST Standby Current Consumption Standby mode @ 3.6V 5 nA
PON Drive level 0.1 µW
RfInternal resistor Between XIN32 and XOUT32 10 MΩ
CLEXT Maximum external capacitor on XIN32 and
XOUT32 20 pF
Ccrystal Allowed Crystal Capacitance Load From crystal specification 6 12.5 pF
Cpara Internal Parasitic Capacitance 1.2 1.4 1.6 pF
XIN32 XOUT32
CLEXT Ccrystal CLEXT
SAM3
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45.4.4 32.768 kHz Crystal Characteristics
45.4.5 32.768 kHz XIN32 Clock Input Characteristics in Bypass Mode
Note: 1. These characteristics apply only when the 32.768 kHz crystal oscillator is in Bypass mode (i.e., when
SUPC_MR.OSCBYPASS = 1 and SUPC_CR.XTALSEL = 1.)
Figure 45-13. XIN32 Clock Timing
Table 45-18. Crystal Characteristics
Symbol Parameter Conditions Min Typ Max Unit
ESR Equivalent Series Resistor (RS)
Crystal @ 32.768 kHz
50 100 kΩ
CmMotional capacitance 0.6 3 fF
CSHUNT Shunt capacitance 0.6 2 pF
Table 45-19. XIN32 Clock Electrical Characteristics (In Bypass Mode)
Symbol Parameter Conditions Min Max Unit
1/(tCPXIN32) XIN32 Clock Frequency (1) 44 kHz
tCPXIN32 XIN32 Clock Period (1) 22 µs
tCHXIN32 XIN32 Clock High Half-period (1) 11 µs
tCLXIN32 XIN32 Clock Low Half-period (1) 11 µs
tCLCH Rise Time 400 ns
tCHCL Fall Time 400 ns
CIN XIN32 Input Capacitance 6 pF
RIN XIN32 Pull-down Resistor 3 5 MΩ
VXIN32_IL VXIN32 Input Low-level Voltage -0.3 0.3 × VDDBU V
VXIN32_IH VXIN32 Input High-level Voltage 0.7 × VDDBU VDDBU + 0.3 V
tCPXIN32
tCLXIN32
tCHXIN32 tCLCH tCHCL
VXIN32_IL
VXIN32_IH
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45.4.6 3 to 20 MHz Crystal Oscillator Characteristics
Figure 45-14. 3 to 20 MHz Crystal Oscillator Schematic
CLEXT = 2 × (Ccrystal - CLOAD - CPCB)
where:
CPCB is the capacitance of the printed circuit board (PCB) track layout from the crystal to the SAM3 pin.
Table 45-20. 3 to 20 MHz Crystal Oscillator Characteristics
Symbol Parameter Conditions Min Typ Max Unit
fOSC Operating Frequency Normal mode with crystal 3 16 20 MHz
fOSC(bypass) Operating Frequency In Bypass Mode External Clock on XIN 50 MHz
Vrip(VDDPLL) Supply Ripple Voltage (on VDDPLL) RMS value, 10 kHz to 10 MHz 30 mV
Duty Cycle 40 50 60 %
tSTART Startup Time
3 MHz, CSHUNT = 3 pF
8 MHz, CSHUNT = 7 pF
12 to 16 MHz, CSHUNT = 7 pF
20 MHz, CSHUNT = 7 pF
14.5
4
1.4
1
ms
IDDON Current Consumption
3 MHz
8 MHz
12 to 16 MHz
20 MHz
150
150
300
400
250
250
450
550
µA
IDD(standby) Standby Current Consumption Standby mode @ 3.6V 5 nA
PON Drive Level
3 MHz
8 MHz
12 MHz, 16 MHz, 20 MHz
15
30
50
µW
RfInternal Resistor Between XIN and XOUT 1 MΩ
CLEXT Maximum external capacitor on XIN and
XOUT 10 pF
Ccrystal Allowed Crystal Capacitance Load From crystal specification 12.5 17.5 pF
CLOAD Internal Equivalent Load Capacitance Integrated Load Capacitance (XIN and
XOUT in series) 7.5 9.5 12 pF
XIN XOUT
CLEXT
CLOAD
CLEXT Ccrystal
SAM3
R = 1K if crystal frequency is lower than 8 MHz
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45.4.7 3 to 20 MHz Crystal Characteristics
45.4.8 3 to 20 MHz XIN Clock Input Characteristics in Bypass Mode
Figure 45-15. XIN Clock Timing
Table 45-21. Crystal Characteristics
Symbol Parameter Conditions Min Typ Max Unit
ESR Equivalent Series Resistor (RS)
Fundamental @ 3 MHz
Fundamental @ 8 MHz
Fundamental @ 12 MHz
Fundamental @ 16 MHz
Fundamental @ 20 MHz
200
100
80
80
50
Ω
CmMotional capacitance 8fF
CSHUNT Shunt capacitance 7pF
Table 45-22. XIN Clock Electrical Characteristics (In Bypass Mode)
Symbol Parameter Conditions Min Typ Max Unit
1/(tCPXIN) XIN Clock Frequency
3–20 MHz crystal oscillator
in Bypass mode
50 MHz
tCPXIN XIN Clock Period 20 ns
tCHXIN XIN Clock High Half-period 8 ns
tCLXIN XIN Clock Low Half-period 8 ns
tCLCH Rise Time 400 ns
tCHCL Fall Time 400 ns
CiXIN Input Capacitance 6pF
RIN XIN Pull-down Resistor 1 MΩ
VXIN_IL VXIN Input Low-level Voltage -0.3 0.3 × VDDPLL V
VXIN_IH VXIN Input High-level Voltage 0.7 × VDDPLL VDDPLL + 0.3 V
tCPXIN
tCLXIN
tCHXIN
tCLCH tCHCL
VXIN_IL
VXIN_IH
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
45.4.9 Crystal Oscillator Design Consideration Information
45.4.9.1 Choosing a Crystal
When choosing a crystal for the 32.768 kHz Slow Clock Oscillator or for the 3–20 MHz Oscillator, several
parameters must be taken into account. Important parameters between crystal and SAM3 specifications are as
follows:
Load Capacitance
Ccrystal is the equivalent capacitor value the oscillator must “show” to the crystal in order to oscillate at the
target frequency. Crystal must be chosen according to the internal load capacitance (CLOAD) of the on-chip
oscillator. Having a mismatch for the load capacitance will result in a frequency drift.
Drive Level
Crystal drive level ≥ Oscillator Drive Level. Having a crystal drive level number lower than the oscillator
specification may damage the crystal.
Equivalent Series Resistor (ESR)
Crystal ESR ≤ Oscillator ESR Max. Having a crystal with ESR value higher than the oscillator may cause the
oscillator to not start.
Shunt Capacitance
Max. crystal Shunt capacitance ≤ Oscillator Shunt Capacitance (CSHUNT). Having a crystal with ESR value
higher than the oscillator may cause the oscillator to not start.
45.4.9.2 Printed Circuit Board (PCB)
SAM3 oscillators are low-power oscillators requiring particular attention when designing PCB systems.
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45.5 UPLL, PLLA Characteristics
Note: 1. Required for 12 MHz Clock Signal injection on XIN pin (oscillator in Bypass mode).
Table 45-23. Supply Voltage Phase Lock Loop Characteristics
Symbol Parameter Conditions Min Typ Max Unit
VDDPLL Supply Voltage 1.6 1.8 1.95 V
Vrip(VDDPLL) Allowable Voltage Ripple RMS value 10 kHz to 10 MHz
RMS value > 10 MHz
30
10 mV
Table 45-24. PLLA Characteristics
Symbol Parameter Conditions Min Typ Max Unit
fIN Input Frequency 1 40 MHz
fOUT Output Frequency 80 240 MHz
IPLL Current Consumption
Active mode @ 96 MHz @ 1.8V
Active mode @ 160 MHz @ 1.8V
Active mode @ 192 MHz @ 1.8V
1
1.6
2.4
1.3
2
3
mA
Standby mode 1 µA
tsSettling Time 200 µs
Table 45-25. UPLL Characteristics for USB High Speed Device Port
Symbol Parameter Conditions Min Typ Max Unit
fIN Input Frequency 12 MHz
fIN(accuracy) Input Frequency Accuracy (1) -0.05 +0.05 %
fOUT Output Frequency 480 MHz
IPLL Current Consumption Active mode @ 480 MHz @ 1.8V 2.5 5 mA
Standby mode 2 µA
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
45.6 USB On-the-Go High Speed Port
45.6.1 Typical Connection
For a typical connection, refer to Section 39. “USB On-The-Go Interface (UOTGHS)”.
For an external connection of the VBG pin, see the figure below.
Figure 45-16. External Connection of VBG Pin
45.6.2 Electrical Characteristics
45.6.2.1 USB Transceiver
USB 2.0 Compliant in full-speed and high-speed modes. Refer to Chapter 7 of the USB 2.0, Revision 2.0 April 27,
2000.
45.6.2.2 VBUS Pin Characteristics
Compliant with On-The-Go and Embedded Host Supplement to the USB Revision 2.0 Specification Revision 2.0
version 1.1a.
45.6.3 Static Power Consumption
Note: 1. If cable is connected add 200 µA (Typical) due to Pull-up/Pull-down current consumption.
VBG
GND
10 pF
6K8 ± 1% Ω
Table 45-26. Electrical Parameters
Symbol Parameter Conditions Min Typ Max Unit
RPUI Bus Pull-up Resistor on Upstream Port (idle bus) In FS or HS Mode 1.5 kΩ
RPUA Bus Pull-up Resistor on Upstream Port (upstream port receiving) In FS or HS Mode 15 kΩ
Table 45-27. Static Power Consumption
Symbol Parameter Conditions Min Typ Max Unit
IBIAS Bias current consumption on VBG 1µA
IVDDUTMII
HS Transceiver & I/O current consumption 8 µA
FS / HS Transceiver & I/O current consumption No connection(1) 3µA
AtmeL
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1402
45.6.4 Dynamic Power Consumption
Note: 1. Including 1 mA due to Pull-up/Pull-down current consumption.
Table 45-28. Dynamic Power Consumption
Symbol Parameter Conditions Min Typ Max Unit
IBIAS Bias current consumption on VBG 0.7 0.8 mA
IVDDUTMII
HS Transceiver current consumption HS transmission 47 60 mA
HS Transceiver current consumption HS reception 18 27 mA
FS/HS Transceiver current consumption FS transmission
0m cable(1) 46mA
FS/HS Transceiver current consumption FS transmission
5m cable(1) 26 30 mA
FS/HS Transceiver current consumption FS reception(1) 34.5mA
AtmeL
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
45.7 12-bit ADC Characteristics
Notes: 1. Use ADC_ACR.IBCTL = 00 for sampling frequency below 500 kHz.
2. Use ADC_ACR.IBCTL = 01 for sampling frequency between 500 kHz and 1 MHz.
Table 45-29. Analog Power Supply Characteristics
Symbol Parameter Conditions Min Typ Max Unit
VDDIN ADC Analog Supply 12-bit or 10-bit resolution 2.4 3.0 3.6 V
10-bit resolution 2.0 3.6 V
Vrip(max) Max. Voltage Ripple RMS value, 10 kHz to 20 MHz 20 mV
IVDDIN Current Consumption
Sleep Mode
Fast Wake Up Mode
Normal Mode (ADC_ACR.IBCTL = 00)(1)
Normal Mode (ADC_ACR.IBCTL = 01)(2)
0.1
1.8
4.7
6
1
2.6
7.1
9
µA
mA
mA
mA
Table 45-30. Channel Conversion Time and ADC Clock
Symbol Parameter Conditions Min Typ Max Unit
fADC ADC Clock Frequency 1 22 MHz
tCP_ADC ADC Clock Period 50 1000 ns
fSSampling Frequency 0.05 1 MHz
tSTART ADC Startup time
From OFF Mode to Normal Mode:
- Voltage Reference OFF
- Analog Circuitry OFF
From Standby Mode to Normal Mode:
- Voltage Reference ON
- Analog Circuitry OFF
20
4
30
8
40
12
µs
tTRACK Track and Hold Time See Section 45.7.2.1 “Track and Hold Time
versus Source Output Impedance” for more
details 160 ns
tCONV Conversion Time 20 tCP_ADC
tsSettling time to change offset
and gain 200 ns
Table 45-31. External Voltage Reference Input
Parameter Conditions Min Typ Max Unit
ADVREF Input Voltage Range, 12-bit 2.4V < VDDIN < 3.6V 2.4 VDDIN V
ADVREF Input Voltage Range, 10-bit 2.0V < VDDIN < 3.6V 2.0 VDDIN V
ADVREF Current 250 µA
ADVREF Input DC impedance 14 kΩ
AtmeL
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45.7.1 Static Performance Characteristics
Minimal code = 0
Maximal code = 4095
ADC resolution = 12 bits (4096)
Temperature range -40 to 100 °C
fADC = 2 MHz, ADC_ACR.IBCTL = 01
In Table 45-32 and Table 45-33, the LSB is relative to analog scale for 12-bit ADC:
Single-ended (ex: ADVREF = 3.0V),
̶Gain = 1, LSB = (3.0V / 4096) = 732 µV
̶Gain = 2, LSB = (1.5V / 4096) = 366 µV
̶Gain = 4, LSB = (750mV / 4096) = 183 µV
Differential (ex: ADVREF = 3.0V),
̶Gain = 0.5, LSB = (6.0V / 4096) = 1465 µV
̶Gain = 1, LSB = (3.0V / 4096) = 732 µV
̶Gain = 2, LSB = (750mV / 4096) = 366 µV
In Table 45-34, the LSB is relative to analog scale for 10-bit ADC: LSB = 3.0V/1024.
Note: 1. ‘x’ in conditions stands for digital 0 or 1
Table 45-32. INL, DNL, 12-bit mode
Symbol Parameter Conditions(1) Min Typ Max Unit
INL Integral Non-linearity
VDDIN 2.4V to < 3.0V
Differential, DIFF = 1, OFF = x, GAIN = xx -2.2 ±1 +2.2 LSB
VDDIN 2.4V to < 3.0V
Single-ended, DIFF = 0, OFF = x, GAIN = xx -1.8 ±1 +1.8 LSB
VDDIN 3.0V to < 3.6V
Differential, DIFF = 1, OFF = x, GAIN = xx -1.4 ±1 +1.4 LSB
VDDIN 3.3V to < 3.6V
Single-ended, DIFF = 0, OFF = x, GAIN = xx -1.2 ±1 +1.2 LSB
DNL Differential Non-linearity
VDDIN 2.4V to < 3.0V
Differential, DIFF = 1, OFF = x, GAIN = xx -0.8 ±0.5 +0.8 LSB
VDDIN 2.4V to < 3.0V
Single-ended, DIFF = 0, OFF = x, GAIN = xx -0.8 ±0.5 +0.8 LSB
VDDIN 3.0V to < 3.6V
Differential, DIFF = 1, OFF = x, GAIN = xx -0.7 ±0.5 +0.7 LSB
VDDIN 3.0V to < 3.6V
Single-ended, DIFF = 0, OFF = x, GAIN = xx -0.7 ±0.5 +0.7 LSB
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Note: 1. ‘x’ in conditions stands for digital 0 or 1
Figure 45-17. Offset and Gain Definitions
Table 45-33. Gain Error, Offset Error, 12-bit mode
Symbol Parameter Conditions(1) Min Typ Max Unit
EGGain Error
VDDIN 2.4V to < 3.0V
Differential, DIFF = 1, OFF = x, GAIN = xx
-1.56
-64
-0.56
-23
+0.29
+12
%
LSB
VDDIN 2.4V to < 3.0V
Single-ended, DIFF = 0, OFF = x, GAIN = xx
-1.56
-64
-0.56
-23
+0.29
+12
%
LSB
VDDIN 3.0V to < 3.6V
Differential, DIFF = 1, OFF = x, GAIN = xx
-1.56
-64
-0.56
-23
+0.29
+12
%
LSB
VDDIN 3.0V to < 3.6V
Single-ended, DIFF = 0, OFF = x, GAIN = xx
-1.56
-64
-0.56
-23
+0.29
+12
%
LSB
EOOffset Error
VDDIN 2.4V to < 3.0V
Differential, DIFF = 1, OFF = x, GAIN = xx 0+11.5+64LSB
VDDIN 2.4V to < 3.0V
Single-ended, DIFF = 0, OFF = x, GAIN = xx -54 +11.5 +80 LSB
VDDIN 3.0V to < 3.6V
Differential, DIFF = 1, OFF = x, GAIN = xx -22 +11.5 +48 LSB
VDDIN 3.0V to < 3.6V
Single-ended, DIFF = 0, OFF = x, GAIN = xx -30 +11.5 +56 LSB
Single Ended case:
Offset and Gain
definitions
Vin
Ymax=4095
ADVref
0
Ga: actual gain
Ga=(YaH-YaL)/XiH
Ga=1+Ge(%)
Ge(%): gain error
Ge(lsb): Ge(%)×Xmax
YaL
YaH
ADVref/2
Ya=Ga×Xi+Oe
YiM=2047
Ya=actual adc codes
Oe=actual offset
Xi=ideal adc codes
Xmax=4095XiM=2047 XiH
XiL
VHVL
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Note: 1. Single-ended or differential mode, any gain values.
Table 45-34. Static Performance Characteristics - 10-bit Mode (1)
Symbol Parameter Conditions Min Typ Max Unit
Resolution 10 Bit
INL Integral Non-linearity -1 ±0.5 +1 LSB
DNL Differential Non-linearity No missing code -1 ±0.5 +1 LSB
EO(uncalib) Offset Error All gain, Differential or Single-ended, no calibration -8 +3 +20 LSB
EG(uncalib) Gain Error without calibration All gain, Differential or Single-ended, no calibration -16 -6 +3 LSB
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
45.7.2 Dynamic Performance Characteristics
The following conditions apply for the characteristics provided in Table 45-35 and Table 45-36:
ADC resolution = 12 bits
Temperature range -40 to 100 °C
fADC = 20 MHz
ADC_ACR.IBCTL = 01
fs = 1 MHz
fIN = 127 kHz
FFT using 1024 points or more
Frequency band = [1–500 kHz]
Nyquist conditions fulfilled
Table 45-35. Dynamic Performance Characteristics in Single-ended and 12-bit Mode
Symbol Parameter Conditions Min Typ Max Unit
SNR Signal to Noise Ratio Single-ended, DIFF = 0, OFF = x, GAIN = 10 66 71 74 dB
Single-ended, Other Cases 57 62 68 dB
THD Total Harmonic Distortion Single-ended, DIFF = 0, OFF = x, GAIN = 10 -71 -84 – dB
Single-ended, Other Cases -67 -80 – dB
SINAD Signal to Noise and Distortion Single-ended, DIFF = 0, OFF = x, GAIN = 10 64 69 74 dB
Single-ended, Other Cases 57 62 68 dB
ENOB Effective Number of Bits Single-ended, DIFF = 0, OFF = x, GAIN = 10 10.4 11.2 12 bits
Single-ended, Other Cases 9.2 10.0 11 bits
Table 45-36. Dynamic Performance Characteristics in Differential and 12-bit Mode
Symbol Parameter Conditions Min Typ Max Unit
SNR Signal to Noise Ratio Differential, DIFF = 1, OFF = x, GAIN = 10 61 66 73 dB
Differential, Other Cases 59 64 67 dB
THD Total Harmonic Distortion Differential, DIFF = 1, OFF = x, GAIN = 10 -67 -83 – dB
Differential, Other Cases -69 -85 – dB
SINAD Signal to Noise and Distortion Differential, DIFF = 1, OFF = x, GAIN = 10 60 65 73 dB
Differential, Other Cases 59 64 67 dB
ENOB Effective Number of Bits Differential, DIFF = 0, OFF = x, GAIN = 10 9.8 10.5 11.5 bits
Differential, Other Cases 9.5 10.3 11.3 bits
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45.7.2.1 Track and Hold Time versus Source Output Impedance
The following figure gives a simplified acquisition path.
Figure 45-18. Simplified Acquisition Path
During the tracking phase the ADC needs to track the input signal during the tracking time shown below:
10-bit mode: tTRACK = 0.042 × ZSOURCE + 160
12-bit mode: tTRACK = 0.054 × ZSOURCE + 205
With tTRACK expressed in ns and ZSOURCE expressed in ohms.
Two cases must be considered:
1. The calculated tracking time (tTRACK) is lower than 15 tCP_ADC.
Set TRANSFER = 1 and TRACKTIM = 0 in ADC_MR.
In this case, the allowed ZSOURCE can be computed versus the ADC frequency with the hypothesis of
tTRACK = 15 × tCP_ADC
Where tCP_ADC = 1/fADC. See Table 45-37.
2. The calculated tracking time (tTRACK) is higher than 15 tCP_ADC.
Set TRANSFER = 1 and TRACKTIM = 0 in ADC_MR.
In this case, a timer will trigger the ADC in order to set the correct sampling rate according to the Track time.
The maximum possible sampling frequency will be defined by tTRACK in nanoseconds, computed by the previous
formula but with minus 15 × tCP_ADC and plus TRANSFER time.
10 bit mode: 1/fS = tTRACK - 15 × tCP_ADC + 5 tCP_ADC
12 bit mode: 1/fS = tTRACK - 15 × tCP_ADC + 5 tCP_ADC
Note: Csample and RON are taken into account in the formulas.
Table 45-37. Source Impedance Values
fADC = ADC clock (MHz) ZSOURCE (kΩ) for 12 bits ZSOURCE (kΩ) for 10 bits
20.00 10 14
16.00 14 19
10.67 22 30
8.00 31 41
6.40 40 52
5.33 48 63
4.57 57 74
4.00 66 85
Sample & HoldMux.
ZSOURCE RON
Csample
ADC
Input
12-bit ADC
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Note: 1. Input Voltage range can be up to VDDIN without destruction or over-consumption.
If VDDIO < VADVREF max input voltage is VDDIO.
45.7.3 ADC Application Information
For more information on data converter terminology, please refer to the application note Data Converter
Terminology (Atmel literature No. 6022) available on www.atmel.com.
3.56 74 97
3.20 83 108
2.91 92 119
2.67 100 130
2.46 109 141
2.29 118 152
2.13 126 164
2.00 135 175
1.00 274 353
Table 45-38. Analog Inputs
Symbol Parameter Conditions Min Typ Max Unit
VIR Input Voltage Range(1) 0V
ADVREF V
Ilkg Input Leakage Current ±0.5 µA
CiInput Capacitance 8pF
Table 45-37. Source Impedance Values (Continued)
fADC = ADC clock (MHz) ZSOURCE (kΩ) for 12 bits ZSOURCE (kΩ) for 10 bits
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45.8 Temperature Sensor
The temperature sensor is connected to channel 15 of the ADC.
The temperature sensor provides an output voltage (VO_TS) that is proportional to absolute temperature (PTAT).
VO_TS linearly varies with a temperature slope dVO_TS/dT = 2.65 mV/°C.
VO_TS equals 0.8V at TA 27°C, with a ±15% accuracy. The VO_TS slope versus temperature dVO_TS/dT = 2.65
mV/°C only shows a ±5% slight variation over process, mismatch and supply voltage.
The user needs to calibrate it (offset calibration) at ambient temperature to eliminate the VO_TS spread at ambient
temperature (±15%).
Table 45-39. Temperature Sensor Characteristics
Symbol Parameter Conditions Min Typ Max Unit
VO_TS Output Voltage TA = 27° C 0.800 V
VO_TS(accuracy) Output Voltage Accuracy TA = 27° C -15 +15 %
dVO_TS/dT Temperature Sensitivity (Slope Voltage
vs Temperature) 2.65 mV/°C
Slope accuracy -5 +5 %
Temperature accuracy
After offset calibration
Over temperature range -40 to 85 °C -5 +5 °C
After offset calibration
Over temperature range 0 to 80 °C -3 +3 °C
tSTART Startup Time After ADC_ACR.TSON =1 20 40 µs
zoOutput Impedance 30 Ω
IVDDCORE Current Consumption 50 100 µA
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45.9 12-bit DAC Characteristics
Notes: 1. External voltage reference for DAC is ADVREF. See the ADC voltage reference characteristics in Table 45-31, “External
Voltage Reference Input,” on page 1403.
Table 45-40. Analog Power Supply Characteristics
Symbol Parameter Conditions Min Typ Max Unit
VDDIN Analog Supply 2.4 3.6 V
Vrip(VDDIN) Max. Voltage Ripple RMS value, 10 kHz to 20 MHz 20 mV
IVDDIN Current Consumption
Sleep Mode 0.05 1 µA
Fast Wake Up 1.8 mA
Normal Mode with 1 Output ON
(DACC_ACR.IBCTLDACCORE = 01, DACC_ACR.IBCTLCHx = 10) 3.4 4.3 7.2 mA
Normal Mode with 2 Outputs ON
(DACC_ACR.IBCTLDACCORE = 01, DACC_ACR.IBCTLCHx = 10) 3.9 5 8.1 mA
Table 45-41. Channel Conversion Time and DAC Clock
Symbol Parameter Conditions Min Typ Max Unit
fDAC Clock Frequency 150MHz
tCP_DAC Clock Period 20 1000 ns
fSSampling Frequency 0.04 2 MHz
tSTART Startup time
From Sleep Mode to Normal Mode:
- Voltage Reference OFF(1)
- DAC Core OFF 23 34 45
µs
From Fast Wake-up to Normal Mode:
- Voltage Reference ON
- DAC Core OFF 2.5 4 5
tCONV Conversion Time 25 tCP_DAC
Table 45-42. Static Performance Characteristics
Symbol Parameter Conditions Min Typ Max Unit
Resolution DAC Clock (fDAC) = 50 MHz,
fs = 2 MHz,
fIN = 127 kHz,
ADC_ACR.IBCTL = 01,
FFT using 1024 points or more,
Frequency band = [10–500 kHz],
Nyquist conditions fulfilled
12 bit
INL Integral Non-linearity -4 ±1 +4 LSB
DNL Differential Non-linearity -3 ±0.5 +3 LSB
EOOffset Error -4 ±2 +4 LSB
EGGain Error -16 ±8 +16 LSB
Table 45-43. Dynamic Performance Characteristics
Symbol Parameter Conditions Min Typ Max Unit
SNR Signal to Noise Ratio DAC Clock (fDAC) = 50 MHz,
fs = 2 MHz,
fIN = 127 kHz,
ADC_ACR.IBCTL = 01,
FFT using 1024 points or more,
Frequency band = [10–500 kHz],
Nyquist conditions fulfilled
64 71 74 dB
THD Total Harmonic Distortion -64 -71 -80 dB
SINAD Signal to Noise and Distortion 62 68 73 dB
ENOB Effective Number of Bits 62 68 73 dB
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Note: 1. External voltage reference for DAC is ADVREF. See the ADC voltage reference characteristics in Table 45-31,
“External Voltage Reference Input,” on page 1403.
Table 45-44. Analog Outputs
Symbol Parameter Conditions Min Typ Max Unit
VOR Voltage Range (1/6) × VADVREF(1) – (5/6) × VADVREF(1) V
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45.10 AC Characteristics
45.10.1 Master Clock Characteristics
45.10.2 I/O Characteristics
Criteria used to define the maximum frequency of the I/Os:
Output duty cycle (40%–60%)
Minimum output swing: 100 mV to VDDIO - 100 mV
Addition of rising and falling time inferior to 75% of the period
Notes: 1. Pin Group 1 = PA3, PA15
2. Pin Group 2 = PA[0–2], PA[4–14], PA[16–31], PB[0–31], PC[0–31]
Table 45-45. Master Clock Waveform Parameters
Symbol Parameter Conditions Min Max Unit
1/(tCPMCK) Master Clock Frequency VDDCORE @ 1.62V 78 MHz
VDDCORE @ 1.8V 90
Table 45-46. I/O Characteristics
Symbol Parameter Conditions Min Max Unit
FreqMax1 Pin Group 1 (1) Maximum output frequency
30 pF VDDIO = 1.62V
VDDIO = 3.0V
45
65 MHz
45 pF VDDIO = 1.62V
VDDIO = 3.0V
34
45
PulseminH1Pin Group 1 (1) High Level Pulse Width
30 pF VDDIO = 1.62V
VDDIO = 3.0V
11
7.7 ns
45 pF VDDIO = 1.62V
VDDIO = 3.0V
14.7
11
PulseminL1Pin Group 1 (1) Low Level Pulse Width
30 pF VDDIO = 1.62V
VDDIO = 3.0V
11
7.7 ns
45 pF VDDIO = 1.62V
VDDIO = 3.0V
14.7
11
FreqMax2 Pin Group 2 (2) Maximum output frequency 25 pF 1.62V < VDDIO < 3.6V 35 MHz
PulseminH2Pin Group 2 (2) High Level Pulse Width 25 pF 1.62V < VDDIO < 3.6V 14.5 ns
PulseminL2Pin Group 2 (2) Low Level Pulse Width 25 pF 1.62V < VDDIO < 3.6V 14.5 ns
Table 45-47. NRSTB Characteristics
Symbol Parameter Conditions Min Typ Max Unit
tNRSTB(filtered) Filtered Pulse Width 1µs
tNRSTB(unfiltered) Unfiltered Pulse Width 100
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45.10.3 SPI Characteristics
Figure 45-19. SPI Master Mode with (CPOL = NCPHA = 0) or (CPOL = NCPHA= 1)
Figure 45-20. SPI Master Mode with (CPOL = 0 and NCPHA = 1) or (CPOL = 1 and NCPHA = 0)
Figure 45-21. SPI Slave Mode with (CPOL = 0 and NCPHA = 1) or (CPOL = 1 and NCPHA = 0)
SPCK
MISO
MOSI
SPI2
SPI0SPI1
SPCK
MISO
MOSI
SPI5
SPI3SPI4
SPCK
MISO
MOSI
SPI6
SPI7SPI8
NPCSS
SPI12 SPI13
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Figure 45-22. SPI Slave Mode with (CPOL = NCPHA = 0) or (CPOL = NCPHA = 1)
45.10.3.1 Maximum SPI Frequency
The following formulas give maximum SPI frequency in Master read and write modes and in Slave read and write
modes.
Master Write Mode
The SPI only sends data to a slave device such as an LCD, for example. The limit is given by SPI2 (or SPI5)
timing. Since it gives a maximum frequency above the maximum pad speed (see Section 45.10.2 “I/O
Characteristics”), the max SPI frequency is defined by the pin FreqMax value.
Master Read Mode
tvalid is the slave time response to output data after detecting an SPCK edge. For a non-volatile memory with
tvalid (or tv) = 12 ns, fSPCKMax = 38.5 MHz at VDDIO = 3.3V.
Slave Read Mode
In slave mode, SPCK is the input clock for the SPI. The max SPCK frequency is given by setup and hold
timings SPI7/SPI8(or SPI10/SPI11). Since this gives a frequency well above the pad limit, the limit in slave
read mode is given by SPCK pad.
Slave Write Mode
For 3.3V I/O domain and SPI6, fSPCKMax = 33 MHz. tsetup is the setup time from the master before sampling
data.
SPCK
MISO
MOSI
SPI9
SPI10 SPI11
NPCS0
SPI14
SPI15
fSPCKMax 1
SPI0orSPI3
()tvalid
+
------------------------------------------------------
=
fSPCKMax 1
SPI6orSPI9
()tsetup
+
-------------------------------------------------------
=
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45.10.3.2 SPI Timings
SPI timings are given for the following domains:
3.3V domain: VDDIO from 3.0V to 3.6V, maximum external capacitor = 30 pF
1.8V domain: VDDIO from 1.65V to 1.95V, maximum external capacitor = 30 pF
Table 45-48. SPI Timings
Symbol Parameter Conditions Min Max Unit
SPI0MISO Setup time before SPCK rises (master) 3.3V domain 15 ns
1.8V domain 19.5 ns
SPI1MISO Hold time after SPCK rises (master) 3.3V domain 0 ns
1.8V domain 0 ns
SPI2SPCK rising to MOSI Delay (master) 3.3V domain 3 ns
1.8V domain 3 ns
SPI3MISO Setup time before SPCK falls (master) 3.3V domain 16 ns
1.8V domain 20 ns
SPI4MISO Hold time after SPCK falls (master) 3.3V domain 0 ns
1.8V domain 0 ns
SPI5SPCK falling to MOSI Delay (master) 3.3V domain 3.5 ns
1.8V domain 3.5 ns
SPI6SPCK falling to MISO Delay (slave) 3.3V domain 16 ns
1.8V domain 20 ns
SPI7MOSI Setup time before SPCK rises (slave) 3.3V domain 0.5 ns
1.8V domain 1.5 ns
SPI8MOSI Hold time after SPCK rises (slave) 3.3V domain 0 ns
1.8V domain 0 ns
SPI9SPCK rising to MISO Delay (slave) 3.3V domain 16 ns
1.8V domain 30 ns
SPI10 MOSI Setup time before SPCK falls (slave) 3.3V domain 0 ns
1.8V domain 0.5 ns
SPI11 MOSI Hold time after SPCK falls (slave) 3.3V domain 1.5 ns
1.8V domain 1.5 ns
SPI12 NPCS Setup time to SPCK (slave) 3.3V domain 5 ns
1.8V domain 6.2 ns
SPI13 NPCS Hold time after SPCK (slave) 3.3V domain 0 ns
1.8V domain 0 ns
SPI14 NPCS Setup time to SPCK (slave) 3.3V domain 5.3 ns
1.8V domain 5.7 ns
SPI15 NPCS Hold time after SPCK (slave) 3.3V domain 0 ns
1.8V domain 0 ns
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Note that in SPI master mode the SAM3X/A does not sample the data (MISO) on the opposite edge where data
clocks out (MOSI) but the same edge is used as shown in Figure 45-19 and Figure 45-20.
45.10.4 MCI Timings
The High Speed MultiMedia Card Interface (HSMCI) supports the MultiMedia Card (MMC) Specification V4.3, the
SD Memory Card Specification V2.0, the SDIO V2.0 specification and CE-ATA V1.1.
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45.10.5 SSC Timings
SSC timings are given for the following domains:
1.8V domain: VDDIO from 1.62V to 1.95V, maximum external capacitor = 25 pF
3.3V domain: VDDIO from 3.0V to 3.6V, maximum external capacitor = 25 pF
Figure 45-23. SSC Transmitter, TK and TF as output
Figure 45-24. SSC Transmitter, TK as input and TF as output
Figure 45-25. SSC Transmitter, TK as output and TF as input
TK (CKI =1)
TF/TD
SSC
0
TK (CKI =0)
TK (CKI =1)
TF/TD
SSC
0
TK (CKI =0)
TK (CKI =1)
TF/TD
SSC
1
TK (CKI =0)
TK (CKI =1)
TF/TD
SSC
1
TK (CKI =0)
TK (CKI=1)
TF
SSC
2
SSC
3
TK (CKI=0)
TD
SSC
4
TK (CKI=1)
TF
SSC
2
SSC
3
TK (CKI=0)
TD
SSC
4
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Figure 45-26. SSC Transmitter, TK and TF as input
Figure 45-27. SSC Receiver RK and RF as input
Figure 45-28. SSC Receiver, RK as input and RF as output
TK (CKI=0)
TF
SSC
5
SSC
6
TK (CKI=1)
TD
SSC
7
RK (CKI=1)
RF/RD
SSC8SSC9
RK (CKI=0)
RK (CKI=0)
RD
SSC8
SSC
9
RK (CKI=1)
RF
SSC
10
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Figure 45-29. SSC Receiver, RK and RF as output
Figure 45-30. SSC Receiver, RK as output and RF as input
RK (CKI=0)
RD
SSC11 SSC12
RK (CKI=1)
RF
SSC13
RK (CKI=1)
RF/RD
SSC11 SSC12
RK (CKI=0)
Table 45-49. SSC Timings
Symbol Parameter Conditions Min Max Unit
Transmitter
SSC0TK edge to TF/TD (TK output, TF output) 1.8V domain
3.3V domain
0(1)
0(1)
2.5(1)
7.3(1) ns
SSC1TK edge to TF/TD (TK input, TF output) 1.8V domain
3.3V domain
6.4(1)
6.4(1)
18.1(1)
19.5(1) ns
SSC2TF setup time before TK edge (TK output) 1.8V domain
3.3V domain
29 - tCPMCK
50 - tCPMCK
ns
SSC3TF hold time after TK edge (TK output) 1.8V domain
3.3V domain
tCPMCK - 15
tCPMCK - 36 ns
SSC4TK edge to TF/TD (TK output, TF input) 1.8V domain
3.3V domain
0 (+ 2 × tCPMCK)(1)
0 (+ 2 × tCPMCK)(1)
2.5 (+ 2 × tCPMCK)(1)
7.3 (+ 2 × tCPMCK)(1) ns
SSC5TF setup time before TK edge (TK input) 1.8V domain
3.3V domain
0
0ns
SSC6TF hold time after TK edge (TK input) 1.8V domain
3.3V domain
tCPMCK
tCPMCK
ns
SSC7TK edge to TF/TD (TK input, TF input) 1.8V domain
3.3V domain
6.4 (+ 3 × tCPMCK)(1)
6.4 (+ 3 × tCPMCK)(1)
18 (+ 3 × tCPMCK)(1)
20 (+ 3 × tCPMCK)(1) ns
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Note: 1. For output signals (TF, TD, RF), Min and Max access times are defined. The Min access time is the time between the TK (or
RK) edge and the signal change. The Max access timing is the time between the TK edge and the signal stabilization.
Figure 45-31 illustrates Min and Max accesses for SSC0. The same applies for SSC1, SSC4, and SSC7, SSC10 and SSC13.
Figure 45-31. Min and Max Access Time of Output Signals
Receiver
SSC8RF/RD setup time before RK edge (RK input) 1.8V domain
3.3V domain
0
0ns
SSC9RF/RD hold time after RK edge (RK input) 1.8V domain
3.3V domain
tCPMCK
tCPMCK
ns
SSC10 RK edge to RF (RK input) 1.8V domain
3.3V domain
5(1)
5(1)
16(1)
16(1) ns
SSC11 RF/RD setup time before RK edge (RK output) 1.8V domain
3.3V domain
16 - tCPMCK
16 - tCPMCK
ns
SSC12 RF/RD hold time after RK edge (RK output) 1.8V domain
3.3V domain
tCPMCK - 5
tCPMCK - 5 ns
SSC13 RK edge to RF (RK output) 1.8V domain
3.3V domain
0(1)
0(1)
1(1)
1(1) ns
Table 45-49. SSC Timings (Continued)
Symbol Parameter Conditions Min Max Unit
TK (CKI =0)
TF/TD
SSC0min
TK (CKI =1)
SSC0max
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45.10.6 SMC Timings
SMC timings are given for the following domains:
1.8V domain: VDDIO from 1.65V to 1.95V, maximum external capacitor = 30 pF
3.3V domain: VDDIO from 3.0V to 3.6V, maximum external capacitor = 50 pF
Timings are given assuming a capacitance load on data, control and address pads.
In the following tables tCPMCK is MCK period.
45.10.6.1 Read Timings
Table 45-50. SMC Read Signals - NRD Controlled (READ_MODE = 1)
Symbol
Parameter Min Max
UnitVDDIO supply 1.8V Domain 3.3V Domain 1.8V Domain 3.3V Domain
NO HOLD SETTINGS (NRD_HOLD = 0)
SMC1Data Setup before NRD High 22.5 18 ns
SMC2Data Hold after NRD High 0 0 ns
HOLD SETTINGS (NRD_HOLD ≠ 0)
SMC3Data Setup before NRD High 20.316 ns
SMC4Data Hold after NRD High 00 ns
HOLD or NO HOLD SETTINGS (NRD_HOLD ≠ 0, NRD_HOLD = 0)
SMC5NBS0/A0, NBS1, NBS2/A1, NBS3,
A2–A25 Valid before NRD High
(NRD_SETUP + NRD_PULSE) ×
tCPMCK - 20
(NRD_SETUP + NRD_PULSE) ×
tCPMCK - 20 ns
SMC6NCS low before NRD High (NRD_SETUP + NRD_PULSE -
NCS_RD_SETUP) × tCPMCK - 20
(NRD_SETUP + NRD_PULSE -
NCS_RD_SETUP) × tCPMCK - 20 ns
SMC7NRD Pulse Width nrd pulse × tCPMCK - 3nrd pulse × tCPMCK - 3ns
Table 45-51. SMC Read Signals - NCS Controlled (READ_MODE = 0)
Symbol
Parameter Min Max
UnitVDDIO supply 1.8V Domain 3.3V Domain 1.8V Domain 3.3V Domain
NO HOLD SETTINGS (NCS_RD_HOLD = 0)
SMC8Data Setup before NCS High 26.3 24.6 ns
SMC9Data Hold after NCS High 0 0 ns
HOLD SETTINGS (NCS_RD_HOLD ≠ 0)
SMC10 Data Setup before NCS High 24.1 22.4 ns
SMC11 Data Hold after NCS High 0 0 ns
HOLD or NO HOLD SETTINGS (NCS_RD_HOLD ≠ 0, NCS_RD_HOLD = 0)
SMC12 NBS0/A0, NBS1, NBS2/A1, NBS3,
A2–A25 valid before NCS High
(NCS_RD_SETUP +
NCS_RD_PULSE) × tCPMCK - 3
(NCS_RD_SETUP +
NCS_RD_PULSE) × tCPMCK - 3 ns
SMC13 NRD low before NCS High
(NCS_RD_SETUP +
NCS_RD_PULSE -
NRD_SETUP) × tCPMCK + 0.7
(NCS_RD_SETUP +
NCS_RD_PULSE -
NRD_SETUP) × tCPMCK + 0.6
ns
SMC14 NCS Pulse Width NCS_RD_PULSE length ×
tCPMCK - 6
NCS_RD_PULSE length ×
tCPMCK - 6 ns
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45.10.6.2 Write Timings
Notes: 1. Hold length = total cycle duration - setup duration - pulse duration. “Hold length” is for “NCS_WR_HOLD length” or
“NWE_HOLD length”.
Table 45-52. SMC Write Signals - NWE Controlled (WRITE_MODE = 1)
Symbol
Parameter Min Max
UnitVDDIO supply 1.8V Domain 3.3V Domain 1.8V Domain 3.3V Domain
HOLD or NO HOLD SETTINGS (NWE_HOLD ≠ 0, NWE_HOLD = 0)
SMC15 Data Out Valid before NWE High NWE_PULSE × tCPMCK - 7.5 NWE_PULSE × tCPMCK - 7 ns
SMC16 NWE Pulse Width NWE_PULSE × tCPMCK - 3 NWE_PULSE × tCPMCK - 3 ns
SMC17 NBS0/A0 NBS1, NBS2/A1, NBS3,
A2–A25 valid before NWE low NWE_SETUP × tCPMCK + 6 NWE_SETUP × tCPMCK + 6 ns
SMC18 NCS low before NWE high
(NWE_SETUP -
NCS_RD_SETUP +
NWE_PULSE) × tCPMCK + 10
(NWE_SETUP -
NCS_RD_SETUP +
NWE_PULSE) × tCPMCK + 12
ns
HOLD SETTINGS (NWE_HOLD ≠ 0)
SMC19
NWE High to Data OUT, NBS0/A0
NBS1, NBS2/A1, NBS3, A2–A25
change
NWE_HOLD × tCPMCK - 2.4 NWE_HOLD × tCPMCK - 1.8 ns
SMC20 NWE High to NCS Inactive(1) (NWE_HOLD - NCS_WR_HOLD)
× tCPMCK - 0.3
(NWE_HOLD - NCS_WR_HOLD)
× tCPMCK - 0.3 ns
NO HOLD SETTINGS (NWE_HOLD = 0)
SMC21
NWE High to Data OUT, NBS0/A0
NBS1, NBS2/A1, NBS3, A2–A25,
NCS change(1) 44 ns
Table 45-53. SMC Write NCS Controlled (WRITE_MODE = 0)
Symbol
Parameter Min Max
UnitVDDIO supply 1.8V Domain 3.3V Domain 1.8V Domain 3.3V Domain
SMC22 Data Out Valid before NCS High NCS_WR_PULSE × tCPMCK - 1 NCS_WR_PULSE × tCPMCK - 1 ns
SMC23NCS Pulse Width NCS_WR_PULSE × tCPMCK - 6 NCS_WR_PULSE × tCPMCK - 6 ns
SMC24 NBS0/A0 NBS1, NBS2/A1, NBS3,
A2–A25 valid before NCS low NCS_WR_SETUP × tCPMCK - 5 NCS_WR_SETUP × tCPMCK - 5 ns
SMC25 NWE low before NCS high
(NCS_WR_SETUP -
NWE_SETUP + NCS pulse) ×
tCPMCK + 1.3
(NCS_WR_SETUP -
NWE_SETUP + NCS pulse) ×
tCPMCK + 1.3
ns
SMC26
NCS High to Data Out, NBS0/A0,
NBS1, NBS2/A1, NBS3, A2–A25,
change
NCS_WR_HOLD × tCPMCK - 8.2 NCS_WR_HOLD × tCPMCK - 9.6 ns
SMC27 NCS High to NWE Inactive (NCS_WR_HOLD - NWE_HOLD)
× tCPMCK - 6.2
(NCS_WR_HOLD - NWE_HOLD)
× tCPMCK - 9 ns
SS
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1424
Figure 45-32. SMC Timings - NCS Controlled Read and Write
Figure 45-33. SMC Timings - NRD Controlled Read and NWE Controlled Write
NRD
NCS
D0–D15
NWE
NCS Controlled READ
with NO HOLD
NCS Controlled READ
with HOLD
NCS Controlled WRITE
SMC22 SMC26
SMC10 SMC11
SMC12
SMC9
SMC8
SMC14 SMC14 SMC23
SMC27
SMC26
A
0/A1/NBS[3:0]/A2–A25
SMC24
SMC25
SMC12
SMC13 SMC13
NRD
NCS
D0–D31
NWE
A
0/A1/NBS[3:0]/
A2–A25
NRD Controlled READ
with NO HOLD
NWE Controlled WRITE
with NO HOLD
NRD Controlled READ
with HOLD
NWE Controlled WRITE
with HOLD
SMC1 SMC2 SMC15
SMC21
SMC3 SMC4 SMC15 SMC19
SMC20
SMC7
SMC21
SMC16
SMC7
SMC16
SMC19
SMC21
SMC17
SMC18
SMC5 SMC5
SMC6 SMC6
SMC17
SMC18
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Notes: 1. 3V domain: VDDIO from 3.0V to 3.6V, maximum external capacitor on data, control and address = 50 pF, maximum
external capacitor on clock = 10 pF
2. 3.3V domain: VDDIO from 3.3V to 3.6V, maximum external capacitor on data, control and address = 50 pF,
maximum external capacitor on clock = 10 pF
3. Control is the tNSSet of following signals : SDCKE, SDCS, RAS, CAS, SDA10, BAx, DQMx, and SDWE
4. Address is the set of A0–A9, A11–A13
Notes: 1. 3V domain: VDDIO from 3.0V to 3.6V, maximum external capacitor on data, control and address = 50 pF, maximum
external capacitor on clock = 10 pF
2. 3.3V domain: VDDIO from 3.3V to 3.6V, maximum external capacitor on data, control and address = 50 pF,
maximum external capacitor on clock = 10 pF
3. Control is the tNSSet of following signals: SDCKE, SDCS, RAS, CAS, SDA10, BAx, DQMx, and SDWE
4. Address is the set of A0–A9, A11–A13
Notes: 1. 1.8V domain: VDDIO from 1.62V to 1.95V, maximum external capacitor on data, control and address = 30 pF,
maximum external capacitor on clock = 10 pF
2. Control is the tNSSet of following signals : SDCKE, SDCS, RAS, CAS, SDA10, BAx, DQMx, and SDWE
3. Address is the set of A0–A9, A11–A13
Table 45-54. SDRAM PC100 Characteristics
Parameter
Min Max
Unit3V Supply(1) 3V Supply(1) 3.3V Supply(2)
SDRAM Controller Clock Frequency 76.9 92 MHz
Control/Address/Data In Setup(3)(4) 2ns
Control/Address/Data In Hold(3)(4) 1ns
Data Out Access time after SDCK rising 6 6 ns
Data Out change time after SDCK rising 3 ns
Table 45-55. SDRAM PC133 Characteristics
Parameter
Min Max
Unit3V Supply(1) 3V Supply(1) 3.3V Supply(2)
SDRAM Controller Clock Frequency 80.6 100 MHz
Control/Address/Data In Setup(3)(4) 1.5 ns
Control/Address/Data In Hold(3)(4) 0.8 ns
Data Out Access time after SDCK rising 5.4 5.4 ns
Data Out change time after SDCK rising 3.0 ns
Table 45-56. Mobile Characteristics
Parameter
Min Max
Unit1.62V Supply(1) 1.62V Supply(1) 1.8V Supply(1)
SDRAM Controller Clock Frequency 71.9 84 MHz
Control/Address/Data In Setup(2)(3) 1.5 ns
Control/Address/Data In Hold(2)(3) 1ns
Data Out Access time after SDCK rising 6 6 ns
Data Out change time after SDCK rising 2.5 ns
fl AtmeL
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1426
45.10.7 USART in SPI Mode Timings
USART in SPI mode timings are given for the following domains:
1.8V domain: VDDIO from 1.62V to 1.95V, maximum external capacitor = 30 pF
3.3V domain: VDDIO from 3.0V to 3.6V, maximum external capacitor = 30 pF
Figure 45-34. USART SPI Master Mode
Figure 45-35. USART SPI Slave mode (Mode 1 or 2)
NSS
SPI0
MSB LSB
SPI1
CPOL=1
CPOL=0
MISO
MOSI
SCK
SPI5
SPI2
SPI3
SPI4
SPI4
• MOSI line is driven by the output pin TXD
• MISO line drives the input pin RXD
• SCK line is driven by the output pin SCK
• NSS line is driven by the output pin RTS
SCK
MISO
MOSI
SPI6
SPI7SPI8
NSS
SPI12 SPI13
• MOSI line drives the input pin RXD
• MISO line is driven by the output pin TXD
• SCK line drives the input pin SCK
• NSS line drives the input pin CTS
WW
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Figure 45-36. USART SPI Slave mode
(Mode 0 or 3
)
SCK
MISO
MOSI
SPI9
SPI10 SPI11
NSS
SPI14
SPI15
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1428
Table 45-57. USART SPI Timings
Symbol Parameter Conditions Min Max Unit
Master Mode
SPI0tCPSCK Period 1.8V domain
3.3V domain tCPMCK / 6 ns
SPI1Input Data Setup Time 1.8V domain
3.3V domain 0.5 × tCPMCK + 7.7 ns
SPI2Input Data Hold Time 1.8V domain
3.3V domain
1.5 × tCPMCK + 1.8
1.5 × tCPMCK + 0.7 ns
SPI3Chip Select Active to Serial Clock 1.8V domain
3.3V domain 1.5 × tCPSCK -1 ns
SPI4Output Data Setup Time 1.8V domain
3.3V domain 07.4ns
SPI5Serial Clock to Chip Select Inactive 1.8V domain
3.3V domain 1 × tCPSCK - 1 ns
Slave Mode
SPI6tCPSCK falling to MISO 1.8V domain
3.3V domain 730ns
SPI7MOSI Setup time before tCPSCK rises 1.8V domain
3.3V domain 2 × tCPMCK + 6.8 ns
SPI8MOSI Hold time after tCPSCK rises 1.8V domain
3.3V domain 1ns
SPI9tCPSCK rising to MISO 1.8V domain
3.3V domain 7ns
SPI10 MOSI Setup time before tCPSCK falls 1.8V domain
3.3V domain 2 × tCPMCK + 6 ns
SPI11 MOSI Hold time after tCPSCK falls 1.8V domain
3.3V domain
2.7
1ns
SPI12 NPCS0 setup to tCPSCK rising 1.8V domain
3.3V domain 2.5 × tCPMCK +1 ns
SPI13 NPCS0 hold after tCPSCK falling 1.8V domain
3.3V domain 1.5 × tCPMCK + 4 ns
SPI14 NPCS0 setup to tCPSCK falling 1.8V domain
3.3V domain 2.5 × tCPMCK + 0.4 ns
SPI15 NPCS0 hold after tCPSCK rising 1.8V domain
3.3V domain 1.5 × tCPMCK + 2.7 ns
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
45.10.8 EMAC
Notes: 1. For EMAC output signals, Min and Max access time are defined. The Min access time is the time between the
EDMC rising edge and the signal change. The Max access timing is the time between the EDMC rising edge and
the signal stabilizes. Figure 45-37 illustrates Min and Max accesses for EMAC3.
Figure 45-37. Min and Max Access Time of EMAC Output Signals
45.10.8.1 MII Mode
Table 45-58. EMAC Signals Relative to EMDC
Symbol Parameter Conditions Min Max Unit
EMAC1Setup for EMDIO from EMDC rising
VDDIO from 3.0V to 3.6V,
maximum external capacitor = 20 pF
10
nsEMAC2Hold for EMDIO from EMDC rising 10
EMAC3EMDIO toggling from EMDC rising 0(1) 300(1)
EMDC
EMDIO
EMAC
3 max
EMAC
1
EMAC
2
EMAC
4
EMAC
5
EMAC
3 min
Table 45-59. EMAC MII Specific Signals
Symbol Parameter Conditions Min Max Unit
EMAC4Setup for ECOL from ETXCK rising
VDDIO from 3.0V to 3.6V,
maximum external capacitor = 20 pF
10
ns
EMAC5Hold for ECOL from ETXCK rising 10
EMAC6Setup for ECRS from ETXCK rising 10
EMAC7Hold for ECRS from ETXCK rising 10
EMAC8ETXER toggling from ETXCK rising 10 25
EMAC9ETXEN toggling from ETXCK rising 10 25
EMAC10 ETX toggling from ETXCK rising 10 25
EMAC11 Setup for ERX from ERXCK 10
EMAC12 Hold for ERX from ERXCK 10
EMAC13 Setup for ERXER from ERXCK 10
EMAC14 Hold for ERXER from ERXCK 10
EMAC15 Setup for ERXDV from ERXCK 10
EMAC16 Hold for ERXDV from ERXCK 10
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1430
Figure 45-38. EMAC MII Mode
EMDC
EMDIO
ECOL
ECRS
ETXCK
ETXER
ETXEN
ETX[3:0]
ERXCK
ERX[3:0]
ERXER
ERXDV
EMAC3
EMAC1EMAC2
EMAC4EMAC5
EMAC6EMAC7
EMAC8
EMAC9
EMAC10
EMAC11 EMAC12
EMAC13 EMAC14
EMAC15 EMAC16
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
45.10.8.2 RMII Mode
Figure 45-39. EMAC RMII Timings
Table 45-60. RMII Mode
Symbol Parameter Conditions Min Max Unit
EMAC21 ETXEN toggling from EREFCK rising
VDDIO from 3.0V to 3.6V,
maximum external capacitor = 20 pF
216
ns
EMAC22 ETX toggling from EREFCK rising 2 16
EMAC23 Setup for ERX from EREFCK rising 4
EMAC24 Hold for ERX from EREFCK rising 2
EMAC25 Setup for ERXER from EREFCK rising 4
EMAC26 Hold for ERXER from EREFCK rising 2
EMAC27 Setup for ECRSDV from EREFCK rising 4
EMAC28 Hold for ECRSDV from EREFCK rising 2
EREFCK
ETXEN
ETX[1:0]
ERX[1:0]
ERXER
ECRSDV
EMAC21
EMAC22
EMAC23 EMAC24
EMAC25 EMAC26
EMAC27 EMAC28
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1432
45.10.9 Two-wire Serial Interface Characteristics
Table 45-61 describes the requirements for devices connected to the Two-wire Serial Bus. For timing symbols
refer to Figure 45-40.
Note: 1. Required only for fTWCK > 100 kHz
2. Cb = capacitance of one bus line in pF. Per I2C Standard compatibility, Cb Max = 400 pF
3. The TWCK low period is defined as follows: tLOW = ((CLDIV × 2CKDIV) + 4) × tMCK
4. The TWCK high period is defined as follows: tHIGH = ((CHDIV × 2CKDIV) + 4) × tMCK
5. tCPMCK = MCK bus period
Table 45-61. Two-wire Serial Bus Requirements
Symbol Parameter Conditions Min Max Unit
VIL Input Low-voltage -0.3 0.3 × VDDIO V
VIH Input High-voltage 0.7 × VDDIO VCC + 0.3 V
Vhys Hysteresis of Schmitt Trigger Inputs 0.150 – V
VOL Output Low-voltage 3 mA sink current – 0.4 V
trRise Time for both TWD and TWCK 20 + 0.1Cb(1)(2) 300 ns
tfo Output Fall Time from VIHmin to VILmax 10 pF < Cb < 400 pF
Figure 45-40 20 + 0.1Cb(1)(2) 250 ns
Ci(1) Capacitance for each I/O pin – 10 pF
fTWCK TWCK Clock Frequency 0 400 kHz
Rp Value of Pull-up resistor fTWCK ≤ 100 kHz (VDDIO - 0.4V) ÷ 3mA 1000ns ÷ CbΩ
fTWCK > 100 kHz 300ns ÷ Cb
tLOW Low Period of the TWCK clock fTWCK ≤ 100 kHz (3) –µs
fTWCK > 100 kHz (3) –µs
tHIGH High period of the TWCK clock fTWCK ≤ 100 kHz (4) –µs
fTWCK > 100 kHz (4) –µs
th(start) Hold Time (repeated) START Condition fTWCK ≤ 100 kHz tHIGH –µs
fTWCK > 100 kHz tHIGH –µs
tsu(start) Setup time for a repeated START condition fTWCK ≤ 100 kHz tHIGH –µs
fTWCK > 100 kHz tHIGH –µs
th(data) Data hold time fTWCK ≤ 100 kHz 0 3 × tCPMCK(5) µs
fTWCK > 100 kHz 0 3 × tCPMCK(5) µs
tsu(data) Data setup time fTWCK ≤ 100 kHz tLOW - 3 × tCPMCK(5) –ns
fTWCK > 100 kHz tLOW - 3 × tCPMCK(5) –ns
tsu(stop) Setup time for STOP condition fTWCK ≤ 100 kHz tHIGH –µs
fTWCK > 100 kHz tHIGH –µs
tBUF Bus free time between a STOP and START
condition
fTWCK ≤ 100 kHz tLOW –µs
fTWCK > 100 kHz tLOW –µs
LL AAAAA a H \
DRAFT
1433
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Figure 45-40. Two-wire Serial Bus Timing
tsu(start)
tLOW
tHIGH
tLOW
tfo
th(start) th(data) tsu(data) tsu(stop)
tBUF
TWCK
TWD
tr
tsu(start)
tLOW
tHIGH
tLOW
tfo
th(start) th(data) tsu(data) tsu(stop)
tBUF
TWCK
TWD
tr
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1434
45.10.10 Embedded Flash Characteristics
The maximum operating frequency given in Table 45-62 is limited by the Embedded Flash access time when the
processor is fetching code out of it. The table provides the device maximum operating frequency defined by the
value of field FWS in the EEFC_FMR. This field defines the number of wait states required to access the
Embedded Flash Memory.
Note: The embedded flash is fully tested during production test. The flash contents is not set to a known state
prior to shipment. Therefore, the flash contents should be erased prior to programming an application.
Table 45-62. Embedded Flash Wait State - VDDCORE 1.62V/1.80V
EEFC_FMR.FWS Read Operations
Maximum Operating Frequency (MHz)
VDDCORE 1.62V VDDCORE 1.80V
0 1 cycle 17 19
1 2 cycles 45 50
2 3 cycles 58 64
3 4 cycles 70 80
4 5 cycles 78 90
Table 45-63. AC Flash Characteristics
Parameter Conditions Min Typ Max Unit
Program Cycle Time Per page including auto-erase 4.6 ms
Per page without auto-erase 2.3 ms
Full Chip Erase 10 11.5 ms
Data Retention Not Powered or Powered 10 years
Endurance Write/Erase cycles @ 25°C 30K cycles
Write/Erase cycles @ 85°C 10K
:JuL MUEU.’ 47: \. Mum» 4w m , 7mg AtmeL
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
46. Mechanical Characteristics
Figure 46-1. 100-lead LQFP Package Drawing
Table 46-1. 100-lead LQFP Device and Package Maximum Weight
800 mg
Table 46-2. 100-lead LQFP Package Reference
JEDEC Drawing Reference MS-026
JESD97 Classification e3
Table 46-3. 100-lead LQFP Package Characteristics
Moisture Sensitivity Level 3
‘ w? 33933 _ ‘ ‘ [ + \ 7 + L T \E ETJL / p IE; ' g, A; w :— J J J “‘ fl ‘ rLL \ E \ , E V \LU ETE PIE 7 + II] ~a \ ‘77 LTT \E AtmeL
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1436
Figure 46-2. 100-ball TFBGA Package Drawing
Table 46-4. 100-ball TFBGA Package Reference - Soldering Information (Substrate Level)
Ball Land Diameter 0.45 mm
Soldering Mask Opening 0.35 mm
Table 46-5. 100-ball TFBGA Device and Package Maximum Weight
141 mg
Table 46-6. 100-ball TFBGA Package Characteristics
Moisture Sensitivity Level 3
Table 46-7. 100-ball TFBGA Package Reference
JEDEC Drawing Reference MO-275-DDAC-1
JESD97 Classification e8
Bottom View COMMON DIMENSIONS (Unlt or Measure : mm) swam. MIN NOM MAX NOTE Al 0.05 0.15 6 A2 1.35 1.40 1.45 D 22.00 BSC DI 20.00 BSC 2.3 E 22.00 BSC Side View E1 20.00 BSC 2, a e 0.50 380 b 0.17 l 0.22 l 0.27 4.5 L1 1.00 REF Notes: 1. Thls drewlng ls 101 general inlermalien only; reler to JEDEC Drawing Ms-ozs lor addiflonal hbrmanon. 2. The 10p package body slze may be smaller man the bottom package size by as much as 0.15 mm. a. Dlmenslons D1 and E1 do not include mold protrusions. Allowable protrusion Is 025 mm per Slde. m and E1 are maximum plaelic body slze nlmensmns includlng mold mlemeceh. 4. Dlmension 1) does not Include Dambar prolruslon. Allowable Dambar protruslon shall nol cause the lead widlh to exceed the mexlmum b dlmenslon by mere man 0.00 mm, Dambar cannot be harmed en the lower radlus or lhe loot Mlnlmum space between prolmslon am an adjacent lead IS 0 07 mm for 0.4 and 0 5 mm pllch packages. . These dlmensmns apply to me llal secllen e1 lne lead between 0.10 mm and 0.25 mm 1mm me lead llp. . A1 is dellnea as (he dlslance mm the seatlng place to me lewesl pelnl on me package body. mm AtmeL
DRAFT
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Figure 46-3. 144-lead LQFP Package Drawing
Table 46-8. 144-lead LQFP Device and Package Maximum Weight
1400 mg
Table 46-9. 144-lead LQFP Package Characteristics
Moisture Sensitivity Level 3
Table 46-10. 144-lead LQFP Package Reference
JEDEC Drawing Reference MS-026
JESD97 Classification e3
4w mu ,M M'H m n” an m mwm AtmeL
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1438
Figure 46-4. 144-ball LFBGA Package Drawing
Table 46-11. Soldering Information (Substrate Level)
Ball Land 0.380 mm
Soldering Mask Opening 0.280 mm
Table 46-12. 144-ball BGA Device and Package Maximum Weight
300 mg
Table 46-13. 144-ball BGA Package Characteristics
Moisture Sensitivity Level 3
Table 46-14. Package Reference
JEDEC Drawing Reference none
JESD97 Classification e1
All dimensions are in mm
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
46.1 Soldering Profile
Table 46-15 gives the recommended soldering profile from J-STD-020C.
Note: The package is certified to be backward compatible with Pb/Sn soldering profile.
A maximum of three reflow passes is allowed per component.
46.2 Packaging Resources
Land Pattern Definition.
Refer to the following IPC Standards:
IPC-7351A and IPC-782 (Generic Requirements for Surface Mount Design and Land Pattern Standards)
http://landpatterns.ipc.org/default.asp
Atmel Green and RoHS Policy and Package Material Declaration Data Sheet available on www.atmel.com
Table 46-15. Soldering Profile
Profile Feature Green Package
Average Ramp-up Rate (217°C to Peak) 3°C/sec. max.
Preheat Temperature 175°C ± 25°C 180 sec. max.
Temperature Maintained above 217°C 60 sec. to 150 sec.
Time within 5°C of Actual Peak Temperature 20 sec. to 40 sec.
Peak Temperature Range 260°C
Ramp-down Rate 6°C/sec. max.
Time 25°C to Peak Temperature 8 min. max.
ARM AtmeL
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1440
47. Marking
All devices are marked with the Atmel logo and the ordering code.
Additional marking is as follows:
where
“YY”: manufactory year
“WW”: manufactory week
“V”: revision
“XXXXXXXXX”: lot number
YYWW V
XXXXXXXXX ARM
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SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
48. Ordering Information
Table 48-1. SAM3X/A Ordering Information
Ordering Code MRL Flash
(Kbytes) Package Operating Temperature
Range
ATSAM3A4CA-AU A 256 LQFP100 Industrial
-40°C to 85°C
ATSAM3A8CA-AU A 512 LQFP100 Industrial
-40°C to 85°C
ATSAM3A4CA-CU A 256 TFBGA100 Industrial
-40°C to 85°C
ATSAM3A8CA-CU A 512 TFBGA100 Industrial
-40°C to 85°C
ATSAM3X4CA-AU A 256 LQFP100 Industrial
-40°C to 85°C
ATSAM3X8CA-AU A 512 LQFP100 Industrial
-40°C to 85°C
ATSAM3X4CA-CU A 256 TFBGA100 Industrial
-40°C to 85°C
ATSAM3X8CA-CU A 512 TFBGA100 Industrial
-40°C to 85°C
ATSAM3X4EA-AU A 256 LQFP144 Industrial
-40°C to 85°C
ATSAM3X8EA-AU A 512 LQFP144 Industrial
-40°C to 85°C
ATSAM3X4EA-CU A 256 LFBGA144 Industrial
-40°C to 85°C
ATSAM3X8EA-CU A 512 LFBGA144 Industrial
-40°C to 85°C
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Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1442
49. SAM3X/A Series Errata
49.1 Errata Revision A Parts
The table below lists the chip IDs for revision A parts.
Note: 1. This device is not commercially available. Mounted only on the SAM3X-EK evaluation kit.
49.1.1 Flash Memory
49.1.1.1 Flash: Flash Programming
When writing data into the Flash memory plane (either through the EEFC, using the IAP function or FFPI), the data
may not be correctly written (i.e., the data written is not the one expected).
Problem Fix/Workaround
Set the number of Wait States (WS) at 6 (FWS = 6) during the programming.
49.1.1.2 Flash: Fetching Error after Reading the Unique Identifier
After reading the Unique Identifier (or using the STUI/SPUI command), the processor may fetch wrong
instructions. It depends on the code and on the region of the code.
Problem Fix/Workaround
In order to avoid this problem, follow the steps below:
1. Set bit 16 of EEFC Flash Mode Register to 1
2. Send the Start Read Unique Identifier command (STUI) by writing the Flash Command
3. Register with the STUI command.
4. Wait for the FRDY bit to fall
5. Read the Unique ID (and next bits if required)
6. Send the Stop Read Unique Identifier command (SPUI) by writing the Flash Command
7. Register with the SPUI command.
8. Wait for the FRDY bit to rise
9. Clear bit 16 of EEFC Flash Mode Register
Note: During the sequence, the software cannot run out of Flash (so needs to run out of SRAM).
Table 49-1. Revision A Parts Chip IDs
Chip Name Revision Chip ID
SAM3X8H(1) A 0x286E0A60
SAM3X8E A 0x285E0A60
SAM3X4E A 0x285B0960
SAM3X8C A 0x284E0A60
SAM3X4C A 0x284B0960
SAM3A8C A 0x283E0A60
SAM3A4C A 0x283B0960
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49.1.1.3 Flash: Boot Flash Programming Mapping Is Wrong
GPNVM2 enables to select if Flash0 or Flash1 is used for the boot. But when GPNVM2 is set, only the first
64 Kbytes of the Flash 1 are seen in the Boot Memory. The rest of the Boot memory corresponds to Flash 0
content.
Problem Fix/Workaround
No fix required if the code size is less than 64Kbytes. Otherwise the software needs to take into account this
limitation if GPNVM2 is used.
49.1.1.4 Flash: Flash Programming
When writing data into the Flash memory plane (either through the EEFC, using the IAP function or FFPI), the data
may not be correctly written (i.e the data written is not the one expected).
Problem Fix/Workaround
Set the number of Wait States (WS) at 6 (FWS = 6) during the programming.
49.1.2 Backup Mode
49.1.2.1 Backup mode: The PIO States Are Not Kept
When entering in Backup mode, the PIO states are not kept. All the PIOs go into input with pull-up state in Backup
mode.
Problem Fix/Workaround
The issue is of course only present when VDDIO is still supplied in Backup mode. If the VDDIO is required in this
low power mode, either adapt the hardware so that the input with pull-up state is taken into account in the
schematics or use Wait mode instead.
49.1.2.2 Backup Mode: VDDIO/VDDANA
There is an overcurrent consumption in Backup mode on VDDIO and/or VDDANA when VDDIO and/or VDDANA
are supplied.
Problem Fix/Workaround
Two workarounds are possible:
1) Do not supply VDDANA and VDDIO in backup (by using a switch controlled by SHDN pin for example)
2) Use Wait mode instead of Backup Mode.
49.1.2.3 Backup Mode Power-Up Sequence
When waking up from Backup Mode with all VDDIN, VDDIO, VDDANA, VDDUTMI power supplies rising at the
same time, there is an over power consumption on VDDIO.
Problem Fix/ Workaround
The user has to make sure VDDCORE has reached 1.6V before VDDIO starts rising. This might be implemented
with the following control circuitry.
If the internal voltage regulator is used, VDDIN raising 1 ms before VDDIO allows meeting this requirement.
49.1.3 Pulse Width Modulation (PWM)
49.1.3.1 PWM: Write Protection with PIO Lock Feature Not Usable
Write protection mode with PIO lock (WPCMD = 2) can not be used. In this case, the PWM outputs will not be
locked but other PIOs will be locked instead
Problem Fix/Workaround
Use Write protect mode without locking the PIO (WPCMD = 1)
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49.1.4 Analog to Digital Converter (ADC)
49.1.4.1 ADC: First Conversion After Sleep
In sleep mode, first converted data incorrect after Wakeup.
Problem Fix/Workaround
One or more channels must be converted using sleep mode, a dummy channel as first channel of the series can
be used.
49.1.4.2 ADC: Last Conversion Error
In sleep mode, last converted data incorrect before Shutdown.
Problem Fix/Workaround
One or more channels must be converted using sleep mode, a dummy channel as first channel of the series can
be used.
49.1.4.3 ADC: Wrong First Conversions
The first conversions done by the ADC may be erroneous if the maximum gain (x4 in single ended or x2 in
differential mode) is not used. The issue appears after the power-up or if a conversion has not been occurred for 1
minute.
Problem Fix/Workaround
Three workarounds are possible:
1) Perform 16 dummy conversions on one channel (whatever conditions used in term of setup of gain,
single/differential, offset, and channel selected). The next conversions will be correct for any channels and any
settings. Note that these dummy conversions need to be performed if no conversion has occurred for 1 minute or
for a new chip startup.
2) Perform a dummy conversion on a single ended channel on which an external voltage of ADVREF/2 (+/-10%) is
applied. And use the following conditions for this conversion: gain at 4, offset set at 1. The next conversions will be
correct for any channels and any settings. Note that this dummy conversion needs to be performed if no
conversion has occurred for 1 minute or for a new chip startup.
3) Perform a dummy conversion on a differential channel on which the two inputs are connected together and
connected to any voltage (from 0 to ADVREF). And use the following conditions for this conversion: gain at 4,
offset set at 1. The next conversions will be correct for any channels and any settings. Note that this dummy
conversion needs to be performed if no conversion has occurred for 1 minute or for a new chip startup.
49.1.5 JTAG Boundary
49.1.5.1 JJTAG Boundary: PC0/ERASE
In JTAG Boundary Scan mode, the PIO PC0 which is by default the ERASE pin may erase the Flash content if the
pin is set to high level.
Problem Fix/Workaround
Do not use PC0/ERASE (or tie to 0) or set PC0/ERASE at high level during a time lower than 150 ms in Boundary
JTAG Scan mode or program the Flash after using this mode.
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50. Revision History
In the table that follows, the most recent version of the document appears first.
Table 50-1. SAM3X/SAM3A Datasheet Rev. 11057C Revision History
Issue Date Comments
23-Mar-15
Reformatted document; editorial changes throughout; renamed package 100-ball LFBGA to 100-ball TFBGA
throughout
“Description”
Changed “9x general-purpose 32-bit timers, an RTC” to “three 3-channel general-purpose 32-bit timers, a low-power
RTC, a low-power RTT, 256-bit General Purpose Backup Registers”
Added paragraph relating to low-power modes
Section 1. “Features”
Updated description of “Low-power Modes”
Under “Peripherals”:
- changed “32-bit Real Time Timer (RTT) and RTC” to “32-bit low-power Real-time Timer (RTT) and low-power Real-
time Clock (RTC)”
- added bullet “256-bit General Purpose Backup Registers (GPBR)”
Table 1-1 ”Configuration Summary”: added footnote “Available only on SAM3X8H in LFBGA217 package (not
commercially available)” to SDRAM Controller
Section 2. “SAM3X/A Block Diagram”: in all block diagrams (Figure 2-1 through Figure 2-4),
- renumbered three Timer Counter blocks as 0-1-2 (were previously A-B-C)
- corrected JTAG/SWD pin name “TDO” to “TDO/TRACESWO”
- updated SPI signal names
Figure 2-1 ”SAM3A4/8C (100 pins) Block Diagram”: removed duplicated DMA cells from blocks SPI0, SSC, and
HSMCI
Section 3. “Signal Description”
Table 3-1 ”Signal Description List”: updated SPI signal names
Section 3.1 “Design Considerations”: updated to provide title and number of referenced application note
Section 4. “Package and Pinout”
Table 4-2 ”100-ball TFBGA SAM3X4/8E Package and Pinout”: renamed ‘WAKEUP’ to ‘FWUP’ for ball H5
Section 5. “Power Considerations”
Added Section 5.2 “Power-up Considerations”
Figure 5-2 “Single Supply”: corrected main supply range “1.8V-3.6V” to “1.62–3.6 V”
Figure 5-4 “Backup Batteries Used”: corrected main supply range “1.8V-3.6V” to “1.62–3.6 V”
Updated Section 5.7 “Wake-up Sources”
Updated Section 5.8 “Fast Startup”
Section 6. “Input/Output Lines”
Table 6-1 ”System I/O Configuration Pin List”: changed header in first column from “SYSTEM_IO Bit Number” to
“CCFG_SYSIO Bit No.”
Section 6.6 “ERASE Pin”: in first paragraph, added details relative to reprogramming Flash content; in last sentence,
changed “asserting the pin to low does not erase the Flash” to “asserting the pin to high does not erase the Flash”
Removed Section 7. “Processor and Architecture”
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Section 7. “Memories”
Inserted Section 7.1 “Product Mapping” (was previously section 8. “Product Mapping”)
Updated Section 7.2.1 “Internal SRAM”
Section 7.2.2 “Internal ROM”: changed “At any time, the ROM is mapped at address 0x0018 0000” to “At any time, the
ROM is mapped at address 0x0010 0000”
Updated Section 7.2.3.10 “GPNVM Bits”
Section 7.2.4 “Boot Strategies”: deleted sentence “The GPNVM bit can be cleared or set respectively through the
“Clear General-purpose NVM Bit” and “Set General-purpose NVM Bit” commands of the EEFC User Interface” (this
information is already provided in Section 7.2.3.10 “GPNVM Bits”)
Section 8. “System Controller”
Removed Figure 10-1. “System Controller Block Diagram” (redundant with Figure 16-1 “Supply Controller Block
Diagram”)
Section 9. “Peripherals”
Table 9-2 ”Multiplexing on PIO Controller A (PIOA)”: added footnotes providing information on selecting extra functions
Table 9-3 ”Multiplexing on PIO Controller B (PIOB)”: deleted “See the notes” from the ‘Comments’ column for rows
PB0–PB9; added footnotes providing information on selecting extra functions
Table 9-4 ”Multiplexing on PIO Controller C (PIOC)”: added footnote providing information on selecting ERASE as
extra function
Section 11. “Debug and Test Features”
Section 11.5.2 “Debug Architecture”: corrected “Cortex-M3 embeds four functional units” to “Cortex-M3 embeds five
functional units”
Section 20. “SAM3X/A Boot Program”
Section 20.4.3 “USB Device Port”:
- in first paragraph, replaced “from Windows 98SE to Windows XP” with “beginning with Windows 98SE”
- updated link to www.usb.org
- deleted sentence “Unauthorized use of assigned or unassigned USB Vendor ID Numbers and associated Product ID
Numbers is strictly prohibited”
Section 20.4.4 “In Application Programming (IAP) Feature”: replaced two instances of “MC_FSR register” with
“EEFC_FSR”; changed “by reading the NMI vector in ROM (0x00800008)” to “by reading the NMI vector in ROM
(0x00100008)”
Section 23. “External Memory Bus”
Table 23-3 ”EBI Pins and External Static Device Connections”: edited and reorganized column headers
Section 23.8 “Implementation Examples”: reorganized contents
Section 36. “Timer Counter (TC)”
Throughout, replaced instances of “Master clock” or “MCK” d with “peripheral clock”
Throughout, replaced instances of ‘quadrature decoder logic’ with ‘quadrature decoder’ or ‘QDEC’
Section 36.1 “Description”: rewrote text; in second paragraph, TIOA1 replaced with TIOB1; removed Table 37-1. “Timer
Counter Clock Assignment”
Section 36.2 “Embedded Characteristics”:
- corrected number of TC channels from “Three” to “9”
- changed “Two Multi-purpose Input/Output Signals” to “Two multi-purpose input/output signals acting as trigger event”
- deleted “Two global registers that act on all TC channels”
- changed “Configuration Registers can be write protected” to “Register Write Protection”
Section 36.3 “Block Diagram”: inserted Table 36-1 ”Timer Counter Clock Assignment” (was previously in Section 36.1
“Description”) and updated table footnote
Table 50-1. SAM3X/SAM3A Datasheet Rev. 11057C Revision History (Continued)
Issue Date Comments
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Section 36. “Timer Counter (TC)” (cont’d)
Table 36-2 ”Signal Name Description”: updated descriptions of signals ‘INT’ and ‘SYNC’
Table 36-3 ”TC Pin List”: removed ‘FAULT’ pin
Table 36-4 ”I/O Lines”: added TIOA3/PB0, TIOA4/PB2, TIOA5/PB4, TIOB3/PB1, TIOB4/PB3, and TIOB5/PB5
Section 36.5.3 “Interrupt Sources”: changed title (was “Interrupt”) and added Table 36-5 ”Peripheral IDs”
Section 36.6.2 “32-bit Counter”: revised description
Section 36.6.3 “Clock Selection”: renamed internal clock signals to “MCK/2, MCK/8, MCK/32, MCK/128, SLCK”
Section 36.6.11.1 “WAVSEL = 00”: replaced “0xFFFF” with “232-1” in first paragraph
Figure 36-9 “WAVSEL = 10 without Trigger” and Figure 36-10 “WAVSEL = 10 with Trigger”: replaced “0xFFFF” with
“2n-1” (with “n” representing counter size)
Section 36.6.11.3 “WAVSEL = 01”: replaced “0xFFFF” with “232-1” in first paragraph
Figure 36-13 “WAVSEL = 11 without Trigger” and Figure 36-14 “WAVSEL = 11 with Trigger”: replaced “0xFFFF” with
“2n-1” (with “n” representing counter size)
Section 36.6.14.1 “Description”: in first paragraph, corrected instance of TIOA1 to TIOB1; corrected link to Figure 36-15
Section 36.6.14.2 “Input Pre-processing”: deleted sentence “Filters can be disabled using the FILTER bit in the
TC_BMR”
Figure 36-16 “Input Stage”: replaced “FILTER” with “MAXFILTER > 0”
Section 36.6.14.3 “Direction Status and Change Detection”: rewrote sixth paragraph for clarity
Section 36.6.14.4 “Position and Rotation Measurement”: rewrote first paragraph for clarity; corrected instance of TIOA1
to TIOB1; at end of second paragraph, defined External Trigger Edge and External Trigger configuration in TC_CMR
Section 36.6.14.5 “Speed Measurement”: replaced “EDGTRG can be set to 0x01” with “ETRGEDG must be set to
0x01”; replaced “The speed can be read on TC_RA0 register in TC_CMR0” with “The speed can be read on field RA in
register TC_RA0”;
Section 36.6.17 “Register Write Protection”: changed title (was “Write Protection System”) and revised content
Table 36-6 ”Register Mapping”: in last row, defined offset range 0xE8–0xFC as reserved
Section 36.7.2 “TC Channel Mode Register: Capture Mode”: in ‘Name’ line, replaced “(WAVE = 0)” with
“(CAPTURE_MODE)”; updated TCCLKS field description
Section 36.7.3 “TC Channel Mode Register: Waveform Mode”: in ‘Name’ line, replaced “(WAVE = 1)” with
“(WAVEFORM_MODE)”; updated TCCLKS field description; added a note for ENETRG description
Section 36.7.9 “TC Status Register”: added “(cleared on read)” to bit descriptions
Section 36.7.14 “TC Block Mode Register”: removed FILTER bit (register bit 19 now reserved); corrected TC2XC2S
field configuration values: value 2 is TIOA0 (was TIOA1); value 3 is TIOA1 (was TIOA2)
Section 36.7.20 “TC Write Protection Mode Register”: updated descriptions of WPEN bit and WPKEY field
Section 39. “USB On-The-Go Interface (UOTGHS)”
Changed index from [x=1..7] to [x=1..6] in “Name” line of following register descriptions:
- Section 39.6.2.17 “Device DMA Channel x Next Descriptor Address Register”
- Section 39.6.2.18 “Device DMA Channel x Address Register”
- Section 39.6.2.19 “Device DMA Channel x Control Register”
- Section 39.6.2.20 “Device DMA Channel x Status Register”
- Section 39.6.3.22 “Host DMA Channel x Next Descriptor Address Register”
- Section 39.6.3.23 “Host DMA Channel x Address Register”
- Section 39.6.3.24 “Host DMA Channel x Control Register”
- Section 39.6.3.25 “Host DMA Channel x Status Register”
Table 50-1. SAM3X/SAM3A Datasheet Rev. 11057C Revision History (Continued)
Issue Date Comments
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Section 45. “Electrical Characteristics”
Updated and harmonized parameter symbols
Table 45-1 Absolute Maximum Ratings*:
- added “(except VBUS)” to description “Voltage on Input Pins with Respect to Ground”
- added “Voltage on VBUS Pin with Respect to Ground”
Table 45-2 DC Characteristics: removed parameter “Input Capacitance”
Table 45-3 1.8V Voltage Regulator Characteristics: updated condtions for CDIN and CDOUT
Table 45-4 Core Power Supply Brownout Detector Characteristics: added parameter “Reset Period”
Added Table 45-6 ”Threshold Selection”
Table 45-7 Backup Power Supply Zero-Power-on Reset Characteristics: modified parameter name “Reset Time-out
Period” to “Reset Period”
Section 45.3.1 “Backup Mode Current Consumption”: deleted instances of “Configuration A”
Section 45.4.3 “32.768 kHz Crystal Oscillator Characteristics”: added parameter “Allowed Crystal Capacitance Load”
Table 45-17 ”32.768 kHz Crystal Oscillator Characteristics”: updated conditions for parameters “Startup Time” and
“Current Consumption”
Table 45-19 ”XIN32 Clock Electrical Characteristics (In Bypass Mode)”: in table footnote, corrected “32768 kHz” to
“32.768 kHz”
Updated Figure 45-13 “XIN32 Clock Timing”
Table 45-20 ”3 to 20 MHz Crystal Oscillator Characteristics”: added parameter “Allowed Crystal Capacitance Load”;
deleted all footnotes
Updated Figure 45-15 “XIN Clock Timing”
Section 45.4.9.1 “Choosing a Crystal”: under ‘Load Capacitance’, changed “This is the equivalent capacitor” to “Ccrystal
is the equivalent capacitor”
Section 45.4.9.2 “Printed Circuit Board (PCB)”: deleted sentence “A board design example is given on Atmel’s website
in the MCU Technical Center Section.”
Table 45-24 ”PLLA Characteristics”:
- updated Input Frequency values (was 8 MHz min/16 MHz max; is 1 MHz min/40 MHz max)
- updated Output Frequency values (was 96 MHz min/192 MHz max; is 80 MHz min/240 MHz max)
Table 45-25 ”UPLL Characteristics for USB High Speed Device Port”: added max value for Current Consumption
Table 45-30 ”Channel Conversion Time and ADC Clock”: changed max value of ADC Clock Frequency from 20 MHz to
22 MHz
Section 45.6 “USB On-the-Go High Speed Port”: removed section 46.6.5 “USB High Speed Design Guidelines”
Added Section 45.6.2.2 “VBUS Pin Characteristics”
Section 45.7.1 “Static Performance Characteristics”: updated conditions at beginning of section
Inserted new heading Section 45.7.2 “Dynamic Performance Characteristics” and updated content
Figure 45-18 “Simplified Acquisition Path”: inserted correct diagram (was previously graph of offset and gain
definitions)
Section 45.8 “Temperature Sensor”: specified instances of “27°C” as ambient temperature (TA)
Added Table 45-44 ”Analog Outputs”
Figure 45-21 “SPI Slave Mode with (CPOL = 0 and NCPHA = 1) or (CPOL = 1 and NCPHA = 0)”: added ‘MOSI’
Section 45.10.3.1 “Maximum SPI Frequency”: updated description under “Master Write Mode” and “Master Read
Mode”
Table 45-49 ”SSC Timings”: deleted footnote “Timings SSC4 and SSC7 depend...added to timings”
Section 45.10.6 “SMC Timings”: updated conditions
Table 50-1. SAM3X/SAM3A Datasheet Rev. 11057C Revision History (Continued)
Issue Date Comments
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Section 45. “Electrical Characteristics” (cont’d)
Section 45.10.7 “USART in SPI Mode Timings”: updated conditions
Figure 45-39 “EMAC RMII Timings”: inserted RMII-specific diagram (was previously extract of “EMAC MII Mode”
diagram)
Table 45-61 ”Two-wire Serial Bus Requirements”: in bottom row, replaced duplicated parameter “Hold Time (repeated)
START Condition” with new parameter ““Bus free time between a STOP and START condition”
Section 45.10.10 “Embedded Flash Characteristics”: corrected “field FWS of the MC_FMR register” to “field FWS in the
EEFC_FMR”; updated text and replaced two wait state tables with single Table 45-62 ”Embedded Flash Wait State -
VDDCORE 1.62V/1.80V”
Section 46. “Mechanical Characteristics”
Figure 46-2 “100-ball TFBGA Package Drawing”: corrected ‘A’ maximum dimension in inches from 0.0575 to 0.0433
Updated Table 46-4 ”100-ball TFBGA Package Reference - Soldering Information (Substrate Level)”
Updated Table 46-5 ”100-ball TFBGA Device and Package Maximum Weight”
Updated Table 46-6 ”100-ball TFBGA Package Characteristics”
Updated Table 46-7 ”100-ball TFBGA Package Reference”
Updated Table 46-8 ”144-lead LQFP Device and Package Maximum Weight”
Added Section 46.1 “Soldering Profile”
Added Section 46.2 “Packaging Resources”
Inserted Section 47. “Marking” (was previously subsection of Section 49. “SAM3X/A Series Errata”)
Section 48. “Ordering Information”
Section 48-1 “SAM3X/A Ordering Information”: removed “Package Type” column (this information is provided on the
Atmel website); renamed “LFBGA100” to “TFBGA100”
Section 49. “SAM3X/A Series Errata”
Added Section 49.1.2.3 “Backup Mode Power-Up Sequence”
Table 50-1. SAM3X/SAM3A Datasheet Rev. 11057C Revision History (Continued)
Issue Date Comments
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Note: 1. “rfo” indicates changes requested during document review and approval loop.
Doc. Rev.
11057B Comments
Change
Request
Ref.
SDRAM and 217-pin package information removed only from Section “Features”, Section 1.1 “Configuration
Summary” (introduction) and Section 48. “Ordering Information”.8251
“Write protected Registers” added to Section “Features”.8213
Section “Features”, Section 1.1 “Configuration Summary” (introduction) updated.
Figure 2-3 ”SAM3X4/8E (144 pins) Block Diagram” updated.
Section 1.1 “Configuration Summary”, added a note “The SAM3X-EK evaluation kit for the SAM3X and SAM3A
series is mounted with a SAM3X8H in a LFBGA217 package. This device is not commercially available.”
Section 46. “Mechanical Characteristics”, deleted Figure 46-5 “217-ball LFBGA Package Drawing” and the
corresponding tables (46-15, 46-16, 46-17, and 46-18).
Section 48. “Ordering Information” updated, ATSAM3X8H-CU information and the note deleted in Table 48-1.
8316
Added a note explaining that SAM3X8H is not commercially available, and replaced “217-pin” / “217-pin
SAM3X” by “217-pin SAM3X8H” in Figure 2-4, Section 5. “Power Considerations”, Section 7.2.1 “Internal
SRAM”, Section 7.3 “External Memories”, Section 7.3.5 “SDR-SDRAM Controller (217-pin SAM3X8H(l) only)”,
Section 9.3 “Peripheral Signal Multiplexing on I/O Lines”, Section 22.2 “Embedded Characteristics” (DMAC),
Section 23.2 “Embedded Characteristics” (External Memory Bus), Section 26.2 “Embedded Characteristics”
(PDC), Section 29.2 “Embedded Characteristics” (CHIPID), Section 31.2 “Embedded Characteristics” (PIO),
and Section 49.1 “Errata Revision A Parts”.
Section 7. “Memories” added to the Overview.
8318
Section 1.1 “Configuration Summary”, removed SAM3X8H information from Table 1-1 on page 3 and added a
note explaining that SAM3X8H is not commercially available.
Removed entirely Section 4.3 SAM3X8H Package and Pinout.
Updated new notes style: changed the color from red to black.
rfo(1)
Fixed incorrectly displayed figures (due to Adobe Illustrator to PDF conversion problem): Figure 5-5 ”Wake-up
Source”, Figure 25-36 ”NAND Flash Controller Timing Engine”, Figure 25-38 ”Program Page Flow Chart”,
Figure 27-2 ”Typical Slow Clock Crystal Oscillator Connection”, Figure 27-3 ”Main Clock Block Diagram”,
Figure 28-1 ”General Clock Block Diagram”, Figure 28-3 ”Master Clock Controller”, Figure 36-1 ”Timer Counter
Block Diagram”, and Figure 38-3 ”Functional View of the Channel Block Diagram”.
rfo(1)
Doc. Rev.
11057A Comments
Change
Request
Ref.
First Issue
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Table of Contents
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1. Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1 Configuration Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. SAM3X/A Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4. Package and Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.1 SAM3A4/8C and SAM3X4/8C Package and Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2 SAM3X4/8E Package and Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5. Power Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.1 Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.2 Power-up Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.3 Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.4 Typical Powering Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.5 Active Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.6 Low Power Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.7 Wake-up Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.8 Fast Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6. Input/Output Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6.1 General Purpose I/O Lines (GPIO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6.2 System I/O Lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.3 Test Pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.4 NRST Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.5 NRSTB Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.6 ERASE Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7. Memories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7.1 Product Mapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7.2 Embedded Memories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.3 External Memories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
8. System Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
8.1 System Controller and Peripherals Mapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
8.2 Power-on-Reset, Brownout and Supply Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
9. Peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.1 Peripheral Identifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.2 APB/AHB Bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.3 Peripheral Signal Multiplexing on I/O Lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
10. ARM Cortex® M3 Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.1 About this section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.3 About the Cortex-M3 processor and core peripherals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.4 Programmers model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
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10.5 Memory model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
10.6 Exception model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
10.7 Fault handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
10.8 Power management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
10.9 Instruction set summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
10.10 Intrinsic functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
10.11 About the instruction descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
10.12 Memory access instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
10.13 General data processing instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
10.14 Multiply and divide instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
10.15 Saturating instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
10.16 Bitfield instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
10.17 Branch and control instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
10.18 Miscellaneous instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
10.19 About the Cortex-M3 peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
10.20 Nested Vectored Interrupt Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
10.21 System control block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
10.22 System timer, SysTick. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
10.23 Memory protection unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
10.24 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
11. Debug and Test Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
11.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
11.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
11.3 Application Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
11.4 Debug and Test Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
11.5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
12. Reset Controller (RSTC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
12.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
12.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
12.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
12.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
12.5 Reset Controller (RSTC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
13. Real-time Timer (RTT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
13.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
13.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
13.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
13.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
13.5 Real-time Timer (RTT) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
14. Real-time Clock (RTC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
14.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
14.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
14.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
14.4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
14.5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
14.6 Real-time Clock (RTC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
15. Watchdog Timer (WDT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
15.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
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15.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
15.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
15.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
15.5 Watchdog Timer (WDT) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
16. Supply Controller (SUPC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
16.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
16.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
16.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
16.4 Supply Controller Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
16.5 Supply Controller (SUPC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279
17. General Purpose Backup Registers (GPBR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
17.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
17.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
17.3 General Purpose Backup Registers (GPBR) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
18. Enhanced Embedded Flash Controller (EEFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
18.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
18.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
18.3 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
18.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
18.5 Enhanced Embedded Flash Controller (EEFC) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
19. Fast Flash Programming Interface (FFPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
19.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
19.2 Parallel Fast Flash Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
20. SAM3X/A Boot Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
20.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
20.2 Flow Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
20.3 Device Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
20.4 SAM-BA Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
20.5 Hardware and Software Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
21. Bus Matrix (MATRIX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
21.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
21.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
21.3 Memory Mapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
21.4 Special Bus Granting Techniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
21.5 Arbitration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
21.6 System I/O Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
21.7 Write Protect Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
21.8 Bus Matrix (MATRIX) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
22. AHB DMA Controller (DMAC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
22.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
22.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
22.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340
22.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
22.5 DMAC Software Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
22.6 Write Protection Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357
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22.7 AHB DMA Controller (DMAC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
23. External Memory Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382
23.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382
23.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382
23.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
23.4 I/O Lines Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384
23.5 Application Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385
23.6 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
23.7 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387
23.8 Implementation Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
24. AHB SDRAM Controller (SDRAMC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
24.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
24.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
24.3 I/O Lines Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
24.4 Application Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394
24.5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
24.6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
24.7 AHB SDRAM Controller (SDRAMC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405
25. Static Memory Controller (SMC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
25.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
25.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
25.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
25.4 I/O Lines Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
25.5 Multiplexed Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
25.6 Application Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
25.7 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423
25.8 External Memory Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423
25.9 Connection to External Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
25.10 Standard Read and Write Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
25.11 Scrambling/Unscrambling Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
25.12 Automatic Wait States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
25.13 Data Float Wait States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
25.14 External Wait. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
25.15 Slow Clock Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448
25.16 NAND Flash Controller Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450
25.17 SMC Error Correcting Code Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
25.18 Static Memory Controller (SMC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465
26. Peripheral DMA Controller (PDC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
26.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
26.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
26.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505
26.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506
26.5 Peripheral DMA Controller (PDC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508
27. Clock Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519
27.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519
27.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519
27.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 520
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27.4 Slow Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 520
27.5 Main Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522
27.6 Divider and PLL Block. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 524
27.7 UTMI Phase Lock Loop Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525
28. Power Management Controller (PMC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526
28.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526
28.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526
28.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 527
28.4 Master Clock Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528
28.5 Processor Clock Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528
28.6 SysTick Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528
28.7 Peripheral Clock Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528
28.8 Free Running Processor Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529
28.9 Programmable Clock Output Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529
28.10 Fast Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530
28.11 Main Crystal Clock Failure Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531
28.12 Programming Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531
28.13 Clock Switching Details. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534
28.14 Write Protection Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537
28.15 Power Management Controller (PMC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538
29. Chip Identifier (CHIPID) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 567
29.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 567
29.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 567
29.3 Chip Identifier (CHIPID) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 568
30. Synchronous Serial Controller (SSC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574
30.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574
30.2 Embedded Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574
30.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575
30.4 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575
30.5 Pin Name List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 576
30.6 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 576
30.7 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 577
30.8 SSC Application Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588
30.9 Synchronous Serial Controller (SSC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 591
31. Parallel Input/Output Controller (PIO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618
31.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618
31.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618
31.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 619
31.4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 620
31.5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621
31.6 I/O Lines Programming Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 629
31.7 Parallel Input/Output Controller (PIO) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
32. Serial Peripheral Interface (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 676
32.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 676
32.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 676
32.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 677
32.4 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 677
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32.5 Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 678
32.6 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 679
32.7 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 680
32.8 Serial Peripheral Interface (SPI) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 692
33. Two-wire Interface (TWI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708
33.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708
33.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708
33.3 List of Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 709
33.4 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 709
33.5 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 710
33.6 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 710
33.7 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 712
33.8 Master Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713
33.9 Multi-master Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 725
33.10 Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 728
33.11 Two-wire Interface (TWI) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735
34. Universal Asynchronous Receiver Transceiver (UART) . . . . . . . . . . . . . . . . . . . . . . . . . 750
34.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750
34.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750
34.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 751
34.4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 751
34.5 UART Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 752
34.6 Universal Asynchronous Receiver Transceiver (UART) User Interface . . . . . . . . . . . . . . . . . . . . . 758
35. Universal Synchronous Asynchronous Receiver Transmitter (USART) . . . . . . . . . 769
35.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 769
35.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 770
35.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 771
35.4 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 772
35.5 I/O Lines Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 772
35.6 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 773
35.7 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775
35.8 Universal Synchronous Asynchronous Receiver Transmitter (USART) User Interface . . . . . . . . . 823
36. Timer Counter (TC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 856
36.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 856
36.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 856
36.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 857
36.4 Pin Name List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 858
36.5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 858
36.6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 860
36.7 Timer Counter (TC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 879
37. High Speed MultiMedia Card Interface (HSMCI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
37.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
37.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
37.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 910
37.4 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 911
37.5 Pin Name List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 911
37.6 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 912
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37.7 Bus Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 913
37.8 High Speed MultiMediaCard Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916
37.9 SD/SDIO Card Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 936
37.10 CE-ATA Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 937
37.11 HSMCI Boot Operation Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 938
37.12 HSMCI Transfer Done Timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 939
37.13 Write Protection Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 940
37.14 High Speed MultiMedia Card Interface (HSMCI) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . 941
38. Pulse Width Modulation (PWM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 970
38.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 970
38.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971
38.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 972
38.4 I/O Lines Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 972
38.5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 973
38.6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 976
38.7 Pulse Width Modulation (PWM) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1003
39. USB On-The-Go Interface (UOTGHS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1053
39.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1053
39.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1053
39.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1054
39.4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1057
39.5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1058
39.6 USB On-The-Go Interface (UOTGHS) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1086
40. Controller Area Network (CAN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1185
40.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1185
40.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1185
40.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1186
40.4 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1186
40.5 I/O Lines Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1187
40.6 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1187
40.7 CAN Controller Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1188
40.8 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1199
40.9 Controller Area Network (CAN) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1211
41. Ethernet MAC 10/100 (EMAC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1242
41.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1242
41.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1242
41.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1243
41.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1244
41.5 Programming Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1254
41.6 Ethernet MAC 10/100 (EMAC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1257
42. True Random Number Generator (TRNG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1309
42.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1309
42.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1309
42.3 True Random Number Generator (TRNG) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1310
43. Analog-to-Digital Converter (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1317
43.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1317
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43.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1318
43.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1318
43.4 Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1319
43.5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1319
43.6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1321
43.7 Analog-to-Digital Converter (ADC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1331
44. Digital-to-Analog Converter Controller (DACC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1355
44.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1355
44.2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1355
44.3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1356
44.4 Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1356
44.5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1357
44.6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1358
44.7 Analog Converter Controller (DACC) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1362
45. Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1378
45.1 Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1378
45.2 DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1379
45.3 Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1385
45.4 Crystal Oscillators Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1394
45.5 UPLL, PLLA Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1400
45.6 USB On-the-Go High Speed Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1401
45.7 12-bit ADC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1403
45.8 Temperature Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1410
45.9 12-bit DAC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1411
45.10 AC Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1413
46. Mechanical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1435
46.1 Soldering Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1439
46.2 Packaging Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1439
47. Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1440
48. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1441
49. SAM3X/A Series Errata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1442
49.1 Errata Revision A Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1442
50. Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1445
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i
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SAFETY-CRITICAL, MILITARY, AND AUTOMOTIVE APPLICATIONS DISCLAIMER: Atmel products are not designed for and will not be used in connection with any applications where
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