Hi Matt, Just scanning what you sent, I see that your ISR routine is in the wrong place. Needs to be something like this: org 0x00 goto start org 0x04 ISR..... The interrupts always vector to 0x04 when they are turned on. If you have MPLAB loaded, go look at the sample template program files. Just copy that and stick your program into that form. Bill -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body