ICD2 USB, have a error, pls help me !

[Congty]

I have just finished a ICD2 USB. I use PIC18LF4550 and PIC16LF877A for ICD2.My circuit use PIC16LF877A . When I erase 16LF877A by another programmer and then I connect ICD2 to my circuit, it work very good , when I program to 16LF877A again , there are error :

Setting Vdd source to target
ICDWarn0020: Invalid target device id (expected=0x71, read=0x0)
...Reading ICD Product ID
Running ICD Self Test
...Passed
MPLAB ICD 2 Ready

I removed resistor 10k from MCLR , ICD still that error
But I remove crystal , ICD2 can found target device.
Please help me !

 

[zachtheterrible]

I don't think that you're supposed to use any kind of oscillator while you're programming (RC or crystal), just the chip by itself. Can you program the PIC when you're not using the crystal?

 

[Congty]

when I replace 16LF877A and use 18LF4550 or 18F458, I debug it very good.I use crystal 24Mhz. I still program the Pic by ICD when I'm not using the crystal .

 

[Oznog]

There is no reason to remove the crystal.
Do NOT- NOT- remove the 10k resistor between MCLR and Vdd. If you connect MCLR directly to Vdd it can blow the entire board. If you don't put the resistor in there to connect them, the board won't run unless you have MCLR_ON_PIN config bit disabled. But that's a bad option frankly, you can't use ICD with MCLR_ON_PIN disabled.

DO power the ICD2 with the wall wart transformer AND power the target board with its normal power source when it's programming. The ICD2 does not provide enough power to run your board in many cases.

But the programming still passes? I wouldn't be too concerned by that warning then.

A much better forum for this question:
**broken link removed**

 

[William At MyBlueRoom]

10K to 22K is recommended. I usually add a diode but it doesn't seem completely nessary.

http://www.embedinc.com/picprg/icsp.htm