Okay. But if the timer0 source works for Heckler, why won't it work in mine? Everything seems to be working okay, except that I want it to be a single-shot occurrence on the 1/0 button, rather than a continuous loop, as it is for the up/down buttons. I thought the 100mS pause was the period that the count from timer 1 is occurring? Thanks. The reason I posted on Hecklers was because I was hoping to get some input from him.