What's in "handler.asm" ? Doesn't matter realy, since it will never run anyway. Where is the RETFIE ? And why does your ISR "goto loop" ? Isn't "loop" outside of the ISR ?? > bcf INTCON,GIE ;Disable interrupt temporarily > goto loop > goto main ;Catches errors .. we hope! Exactly *what* errors ? Jan-Erik. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist