无法使用REAL ICE或ICD3对PIC32MX进行编程

我最近在我的开发板上替换了PIC32 MX440-512。我能把它编程好5到10次，但是突然我不能编程它。但是MCU似乎还行——它仍然愉快地运行我今天早些时候编程的最后一个固件。我的真正的冰说：我在ICSP连接器的所有引脚上三次检查连续性。然后我尝试了一个ICD3（用一个新的电缆）：正如我所说的，PIC32仍然在快乐地运行最后一个固件。我使用MPLAB X IDE来尝试编程（调试）它。



      以下为原文

    I recently replaced the PIC32MX440-512 on my development board. I was able to program it fine 5 or 10 times, but then suddenly I can't program it.

Yet the MCU seems OK - it's still merrily running the last firmware I programmed onto it earlier today.

My REAL ICE says:
The following memory area(s) will be programmed:
program memory: start address = 0x0, end address = 0xcfff
boot config memory
configuration memory

Device Erased...

Programming...
Failed to program device
Target removed
Target voltage detected
Target Device ID (0xfc000) is an Invalid Device ID. Please check your connections to the Target Device.

REAL ICE removed

Transmission on endpoint 2 failed

I triple-checked continuity on all pins of the ICSP connector. Then I tried a ICD3 (with a new cable):
*****************************************************

Connecting to MPLAB ICD 3...

Currently loaded firmware on ICD 3
Firmware Suite Version.....01.43.35
Firmware type..............PIC32MX

Target voltage detected
Unable to connect to the target device.
Failed to get Device ID

As I said, the PIC32 is still happily running the last firmware loaded.

I'm using MPLAB X IDE to try to program (and debug) it.

What could cause this?