MCP79410 Real-Time Clock Chips

Microchip's MCP7941X series of low-power real-time clocks (RTC) uses digital timing compensation for an accurate clock / calendar, a programmable output control for versatility, a power sense circuit that automatically switches to the backup supply, and nonvolatile memory for data storage. Using a low-cost 32.768 kHz crystal, it tracks time using several internal registers. For communication, the MCP7941X uses the I²C™ bus.

The clock / calendar automatically adjusts for months with fewer than 31 days, including corrections for leap years. The clock operates in the 24-hour or 12-hour format with an AM / PM indicator and settable alarm(s) to the second, minute, hour, day of the week, date, or month. Using the programmable CLKOUT, frequencies of 32.768 kHz, 8.192 kHz and 4.096 kHz and 1 Hz can be generated from the external crystal.

Along with the onboard serial EEPROM and battery backed SRAM memory, a 64-bit protected space is available for a unique ID or MAC address to be programmed at the factory or by the end user. The device is fully accessible through the serial interface while V_CC is between 1.8 V and 5.5 V but can operate down to 1.3 V for timekeeping and SRAM retention only.