I discovered one of DT's posts that explained part of my problem was that I wasn't properly clearing the mismatch. When I did that the On-interrupt for RA3 worked. However, I noticed in the same DT post his statement "Keep in mind that you will get an interrupt on both the Press and Release of the button. You will eventually need to change the interrupt handler to determine which Edge occurred." I am using a momentary switch button that grounds RA3 for this On-interrupt and now I see happening what he was warning about...I get an intterupt on press AND release. However, I don't quite grasp how to modify my interrupt handler "to determine which Edge occurred." Obviously I want the interrupt to respond only to the press and not the release. Is there a way to filter out the release action to prevent the 2nd interrupt?