> b0 - IRQ i/p (pushbutton, 10k pulldown, debounced). NB even though > Option has been set for rising edge trigger, IRQ occurs on falling > edge - comments ?) Apologies, reported believed problem, in fact I was using a previous version of .asm with trigger level set to falling edge. However, problem with b0 IRQ remains -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.