I've just rejoined this list after a few years away ! (Hence I forgot to add a subject TAG first time, sorry !) I have a 16F877 development system I built a few years ago, an now I'm considering moving to newer 18FXXX devices. My development system has a 16F627 with a RS-232 i/f to the PC and uses ICSP to program the 16F877. Q: Is the ICSP spec for 18FXXX devices the same as it was for 16F877, or will I need to modify the programmer to use it with 18FXXX devices (IE is the ICSP spec the same) ? Peter. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.