That maybe something related to the PIC18F2550/4550 silicon design and Microchip USB software stack. Somehow there is always a slight opportunity the whole chip is whipped out (sometime, just the flash memory, sometime, flash+configuration bits) when user is plugging the device to the PC USB port. Before PICkit2 V2.4x release, this seems happened in a high frequency. After V2.5x release, it got better. For PICkit2, this issue has been claimed fixed. The real reason still is not clear and not verified. When one PICKit 2 is dead, you can always using another one (or any other type of PIC programmer, such as ICD2, ICD3, etc) bring it back by re-programming the chip. This is the reason some people recommend to have at least two PICkit 2 for safety reason. (For the low price, and the good performance when it is working, it worth the investment.) Apparently, this happens to user who use Microchip USB stacks for their own application too. Check Microchip forum for more reference. Funny N. Au Group Electronics, http://www.AuElectronics.com ________________________________ From: Forrest Christian To: Microcontroller discussion list - Public. Sent: Tuesday, January 6, 2009 3:14:30 AM Subject: [PIC] PicKit vs ICD I currently use a PicKit2 (along with a couple of non-microchip ICD's), and am considering buying another one (or a PicKit3 more likely) since I really like the way it operates. Like it just works, on pretty much everything I've tried... 3.3V, 5V, ICD-powered, project-powered, etc. etc. etc.. If I'm having a problem with one of the other ICD's I grab the pickit and it just works. I occasionally on here will see people saying things like (paraphrasing), "I need to get another ICD2, and in the meantime I'm using the PicKit2", or similar remarks that indicate that there is something better about the ICD2, but from everything I read, and especially with the newer firmware loads in the PicKit, I sure can't figure out what it is. Did I miss something? -forrest -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist