I understand that the oscillator in a PIC is divided by 4 to get the event clock frequency. Is the input for TMR0 and its optional prescaler the oscillator frequency or the event clock frequency? This is, of course, when the prescaler and TMR0 are programmed to receive input from the clock. Martin McCormick WB5AGZ Stillwater, OK OSU Information Technology Division Network Operations Group -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads