If I remember correctly, someone was trying to single step code with a PIC. Couldn't you achieve this by using a monostable on the OSC1 line connected to a push button. I guess you could also send it a stream of 'X' bits to speed things up a little. Just a thought. Tony PicNPoke Multimedia 16F84 Beginners PIC Tools. **PLUS** - PicNPlay - PicNPlan - PicNPrep - PicNPost PicNPort - DT Type Saver - *new* PicNQuiz. Recent addition - Hex To Source converter. http://www.picnpoke.com Email picnpoke@cdi.com.au