MAX10 JTAG programming issue
Hello everyone,
We have problems reprogramming a MAX10 (10M08SAE144C8G) on some customer boards via JTAG and the USB-Blaster after it has been previously programmed. We are using Quartus Prime 19.1 and the USB-Blaster.
About 40 boards were programmed with identical hardware and VHDL description. After that, about 5 of them could not be reprogrammed again. The affected FPGAs still work without problems, they just can no longer be programmed.
In our design we use the nCONFIG, nSTATUS and CONF_DONE pins as user pins.
We also tried the "Test JTAG Chain" with the JTAG Chain Debugger without success. Attached pictures show the JTAG signals for a broken (broken_TestJTAGChain.png) and a good (good_TestJTAGChain.png) FPGA. The TDO-Signal of the broken one just stay high.
Attached picture "circuit_diagram.png" shows the JTAG circuit.
Have any of you faced a similiar problem?
Thanks,
Daniel