> Personally I like to have the ISR starting at 4, because I don't > like having a GOTO that's not necessary That's a good point Howard. Never thought of that. I've always treated and used the ISR as a separate routine in or after main code. Losing a goto will be quicker. Micros with fast-execution Zero Page indexing (8-bit address) need the source at 00-FF, but I think all PIC fetch/store operations (short range at least) are 1 cycle anyway -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist