Use hardware based on the MC3334 ignition chip from Motorola. It's cheap and will give you a nice square wave from the reluctor to the PIC. The interface to my programmable ignition system uses it. Regards 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