Here is output from the MPLAB console during an attempted connection: PICkit 3 detected Connecting to PICkit 3... Firmware Suite Version...... 01.25.20 Firmware type......................PIC18FJ PICkit 3 Connected. Target Detected Target Device ID (00000000) does not match expected Device ID (00004220). I am using MPLAB v8.46 with PICkit3 programmer. Periodically, I get the PI= C to return 0xe220, rather than 0x0000 for device ID, only a couple bits of= f from the expected value! My laptop does not have a ground connection on the plug to ensure that both= the wall power supply (Agilent E3649A) and computer are at the same ground= potential. Could this be a potential problem? I have verified that the g= round connections of all PIC Vss pins are connected to the same rail on my = breadboard, which the PICkit3 'Gnd' pin and power supply '-' pin are also c= onnected to. The wall power supply provides about 2-4 mA of current to the PIC alone. W= hen the PICkit3 is connected, the current increases to 6-7 mA. ----- Original Message ----- From: "Barry Gershenfeld" To: "Microcontroller discussion list - Public." Sent: Monday, November 22, 2010 4:45:01 PM GMT -05:00 US/Canada Eastern Subject: Re: [PIC] Wrong Device ID for PIC18F87J50 - 0x0000 The "slowly decreasing" statement reminds me of times when I thought I was connected to ground, but wasn't. So make sure that besides all the verifie= d grounds you also verify the ground to the scope and the power supply, and the debugger. Otherwise it kinda sounds like the supply voltage is sagging. You didn't say what you're debugging with, but the ICD's have a "power from target/power from debugger" choice. And don't ask me how I know, but the power has to actually be turned on. Putting in more capacitors gives it more opportunity to "charge up" off of stray supply sources and then work for a few milliseconds. I've never hurt an ICD, but I have sent PM3's back to the factory on two occasions for losing their ability to power the target. Barry ....When looking at the PGC and PGD data during a connect, it seems like > there is some > capacitance between the signal lines and ground. Both the clock and data > signals > slowly decrease in voltage magnitude throughout an attempted > connection/program > operation to the PIC. I added decoupling capacitors between power and > ground, which > temporarily fixed the problem.... > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .