Sorry to bomb the whole list with an ON topic message.... I am trying to simulate a 12C508 program. I tried to setup a pin stimulus file to toggle the GPIO port bit GP0 at instruction 15, 25, and 30. I enabled pin stimulus. Can some one show me how to correctly set up the stimulus file? I couldn't find anything on the MCHIP web page or in the 12C5XX data sheet. Much abliged, - -Mark PS: My wife has a voice operated robotic lawn mower.... Wife speaks "The lawn needs mowing." Robotic Lawn Mower Speaks "Yes Dear"