After lots of Trail and error using a circuit Sim, I designed a proper power switch for VPP. I have yet to implement it on my prototype, but it looks good. The new schematic can be viewed at: http://qwertys.hypermart.net/Mypic.png If anyone could help with the design it would be appreciated. I have the circuit built and tested right next to me. All the voltages seem to be normal, its just that I cant seem to program or read. I think it might be propagation delays, but I cant find any software that lets me adjust for that. Before this, I built the PonyProg but had to modify it for lack of 13v zener, and that circuit didn't work either. This programmer uses the Serial port, not the parallel port. The PIC (PIC16C622-20/P) Is there for reference only. The PICs that I am attempting to use are the PIC 16F627 and 16F628. (I believe it is the same pinout though) The middle part which has 10 "Port" is actually a Header/Connector. This is maintaining compatibility with the PonyProg programmer in pinout (with exception of the inverted pins). With this method I can add new sockets for EEPROMS and other PICs. ----- Original Message ----- From: "Stephen" To: Sent: Wednesday, January 29, 2003 5:56 PM Subject: [PIC]: Designing New PIC Programmer I have looked through some of the Inexpensive Serial PIC Programmers yet most do nod adhere to the RS232 Standard very well or can have some problems. Basing my designs on the Ponyprog programmer http://www.lancos.com/prog.html and the JDM (ludipipo) http://www.ic-prog.com/jdmprog.gif programmers I have added some enhancements including an external power source, a 7805 for chip power, a LM317 or similar regulator for 13v VPP and a Maxim DS229. The Maxim DS229 provides RS232 signal levels. (a MAX232 or similar might work, but There are some flaws in the design with the VPP enable (there is a voltage drop accross R5) so I need that part redesigned. I have built the circuit and tested it, but it won't work! I have tried using IC-prog www.ic-prog.com and the voltages show up, but I fail on read and verify. Here is the circuit: http://qwertys.hypermart.net/Mypic.png -Steve -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads