I've also run into this...so you need to program the part with 5V the first time around, a real pain if the board Vdd is 3.3V, but once you have done it, then you can program to your hearts content with 3.3. John Temples wrote: You can't ICSP bulk erase or program some PICs with Vdd <4.5V. What I've noticed in practice is that programming often works, but erasing doesn't. So your first program of a new chip will be successful since the part is blank, but subsequent attempts to erase will fail. On Mon, 21 Aug 2006, Harold Hallikainen wrote: --------------------------------- Stay in the know. Pulse on the new Yahoo.com. Check it out. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist