The instruction of openMSP430

Byte and Word issues

1 appending ". B" to an instruction makes it a byte operation.

a byte instruction with A register destination clears the high 8 bits of the register to 0. Thus, the following would clear the top byte of the register, leaving the lower byte unchanged:

mov. b rn,rn

2 Adding ". W" (or Nothing) to an instruction makes it a word operation, which is also the default behaviour.

3 P Eripherals is divided into an 8-bit bank and a 16-bit bank.

The 8-bit peripherals must only is accessed using 8-bit instructions; Using a 16-bit access produces garbage in the high byte.

The 16-bit peripherals must only is accessed at even addresses. Byte accesses to even addresses is legal, but not usually useful.

The instruction of openMSP430