Charles,

Thanks, I will have a go at doing the work with DT's interrupts - I'm pretty sure that you are correct.

I wanted to use my own ASM to:

1. Learn more about ASM
2. Learn more about MPLAB and debugging.
3. Learn how to glue ASM into PBP.

The most useful things learnt over the last few days were:

1. Debugging ASM with interrupts in it.
2. After a quickish look at DT's interrupt code I think I may now be able to follow it.

I'd much appreciate your input on getting the code on this thread to run in PBP. Despite playing with 'org' and so on, I keep getting lots of:

Code:
overwrite previous address contents error
Regards Bill Legge