>clip two bypass caps and one small electrolytic off the Vcc line to the chip. These were essentially capacitively loading the MCLR line thru an isolating diode etc. BINGO! This is also the problem I had with ICSP. My hacked PS+ could not stand to have any capacitance across the MCLR line while programming. I was able to make ICSP work with a Picstart Plus by adding an external 5V power supply (from a 9V battery hanging off the programming cable) and a short cable, and temporarily removing these caps via a little jumper. An EPIC programmer is only $99 smackers. THey are a lot better at ICSP, since they are designed for it. The only reason I ended up hacking my PS+ was that I was using an "early adopter" chip, and Microengineering labs didn't have a driver for the EPIC yet because they didn't have a sample of the chip yet. -- Lawrence Lile "NCS@NCSRADIO" 03/07/2003 06:32 PM Please respond to pic microcontroller discussion list To: PICLIST@MITVMA.MIT.EDU cc: Subject: Re: ICSP anyone? I had the same problem on production boards. About half of them wouldn't program using ICSP giving similar messages. In my case, the fix was to clip two bypass caps and one small electrolytic off the Vcc line to the chip. These were essentially capacitively loading the MCLR line thru an isolating diode etc. After I clipped these caps off the boards that wouldn't program, they ALL worked fine. ----- Original Message ----- From: "Chris Loiacono" To: Sent: Friday, March 07, 2003 4:46 PM Subject: ICSP anyone? > Does anyone have more than a basic grasp of PIC ICSP? I have a new board in > front of me with several TQFP & SOIC flash PIC's - (hopefully) set up for > programming each individually thru my PICStart+ with an adapter cable I made > for the occasion. It worked well on the breadboard but not so on my > finished board. I can scope the clock, data and 13V on/MCLR, but MPlab says > the chip isn't blank when starting and fails every time. > > 4 of the 5 pins required for programming stay common among the PICs, but the > /MCLR pins are isolated thru shunt jumpers. > > The clock & data signals from the programmer show as rining pretty > badly.....what else might I consider??? > > > Hence, I am here begging for any clues, help, etc.... > > Chris > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.