On Aug 25, 2011, at 9:12 PM, John Temples wrote: > > http://www.xargs.com/pic/c-faq.html#c18isr Compiler dependencies! Most microcontroller compilers will have a =20 mechanism for defining an 'optimal' ISR linkage, but this is not =20 something that is standardized within the language or library =20 definitions. We've just demonstrated that c18 and the avr-gcc do this =20 quite differently; you never mentioned which compiler you're actually =20 using, but it sounds like you should check what its documentation =20 says... BillW --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .