Sure, for obscure historical reasons, XT is short for crystal. Microchip just shortened it more than usual, if you look at various schematics you will often see crystal shortened to Xtal. CIAO - Martin. ______________________________ Reply Separator _________________________________ Subject: XT Author: pic microcontroller discussion list at Internet Date: 5/25/98 12:05 PM Does anyone know what 'XT' stands for in the OSC config. I guess RC = Resistor Capacitor LP = Low Power HS = High Speed 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