The next few slides will describe the PWM14 control signals and how they affect the output of the D/A. First, though, some mention must be made that in some H8 MCUs, various addresses are shared by different registers within a module. With this being the case customers should be made aware of the IIEC and REGS pointer bits. For the H8S/2148A MCU, for instance, certain functions share addresses with specific peripheral modules. Specifically, the serial ports SC1, SC2 and SCI0 share addresses with IIC1, PWMX and IIC0, respectively. When the IIEC bit in the serial/timer control register (STCR) is set to 0, the SCI registers can be accessed. When it is set to 1, the IIC or PWMX registers can be accessed. The REGS bit is accessible in both the DACNT register and in the DADRB register, so it is always accessible, regardless of how it is set. When REGS is set to 0, DADRA and DADRB are accessible. When it is set to 1, DACR and DACNT are accessible.