> I think the best way is not using these pins at all for any other > activity but if you can't avoid it probably a jumper is the best > way to disconnect the pins from the circuit during the programming That's the way I tend to do it Tamas. I try to keep b6 and b7 free, but if push comes to shove and they have to be used, either a pair of jumpers or solder-bridge pads (not so convenient but cheap). Jumpers are better during development, but can be tiresome when s/w is being changed a lot. In those cases I use a multi-pole switch to disconnect the PIC from the circuit, important with the PS+ because of its low drive capability http://www.piclist.com/techref/microchip/picstartplusicsp.htm As you said, a diode can be used on Mclr, I normally use a BAT46 Schottky -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist