Hi, all:
My FPGA is EP1C12F256C6. The configuration device is EPCS4.
==== Problem Description ====
The board is self-designed, and has bugs. One of these bugs is that AS configuration fails if the USB download cable connects to AS configuration ports. The solution is to download the .pof into EPCS4 firstly using AS ports, then disconnect the download cable to let EPCS4 correctly configure EP1C12F256C6.
The solution is not wise, but works for months. But .... yesterday I suddenly found Quartus Programmer couldn't download the .pof file into EPCS4 using AS ports.
The error message is as follows:
Error: Can't recognize silicon ID for device 1
Error: Operation failed
However, I still can use EPCS4 to configure FPGA if I disconnect the download cable.
==== Efforts made ====
Resolder a new EPCS4, NO effect.
Find poor soldering of ground, resolder ground nets, NO effect.
Search on Internet, but nothing really valuable.
I found the nSTATUS and the nCONFIG were about 20kHz waves before resoldering, which means the configuration has error frame since I turn the option "auto restart reconfiguration if data frame error detected". However, after resoldering, nCONFIG remains low. This went totally wrong!!!
Could anyone here offer a clue of this situation or the solution to my problem? Thank you so much!
