Question: Is the INTM bit reset to 0 after the interrupt subroutine has been completed, or do I have to say 'setc INTM before I say 'ret' in my interrupt subroutine.

Answer: The C2xx requires that you re-enable interrupts at the end of your ISR before returning. This is because the C2xx does not have the RETE instruction as in the C5x. The C2xx only has the RET and RETC instructions. Also, note that to re-enable interrupts you must clear the INTM bit. So you must use CLRC INTM instead of SETC INTM."