Windows sees USB blaster but Quartus doesn't, why?

Terasic blaster and custom board. I've been using this combo successfully for a year now, so I'm asking myself "What's changed?"

Hi,
I observed JTAG signal integrity issues, mainly related to TCK, with some customs designed boards.
Two issues have been identified:

- TCK line can pick up interfering signals, specifically clock signals with fast edges. Utimately, a TCK buffer need to be added.
- on small boards with short TCK line, ringing TCK edges caused false JTAG clocking. Could be fixed by adding a small load capacitor (10 to 22 pF near FPGA)

ASMI IP producing continuous DCLK has been found a popular interference source. Solution is to gate DCLK.

Regards
Frank

Hi,

Any update per FvM response? Also, as you have been using the USB Blaster for a year, is there any changes that you make before the USB Blaster is not detected?

Regards,

Aiman

Well the target board hasn't changed, and I've not knowingly changed anything on Quartus-Windows, but that's still where my suspicion rests. SignalTap is reasonably reliable on a different Windows 10 PC with the same version and ditto on my Windows 11 laptop, so I have evidence that both my Blasters and my target board are fine. Is there no way of persuading Quartus to reveal a few more error diagnostics?

Hi,
I understand your latest problem so that Signaltap is working on some boards and not on some others.

Can you narrow down what has changed?
- different FPGA image
- different PCB production charges
- different FPGA production lots
- BOM changes

It's well possible that newer FPGA production lots involve process modification, e.g. resulting in faster JTAG logic that is more responsive to TCK ringing. If the problem is about signal crosstalk, FPGA configuration changes can have a big impact.

Regards
Frank

I've only got one target board, so it's the same target I've been using all year

Hi,

did anything change at all? If it's new FPGA design, does the same problem occur now with old FPGA design as well?

Can be still something like ESD induced hardware defect.

But it works on a different PC. Please read the whole thread.

Sorry, if I re-read the whole thread, I don't clearly see that you made a test with different PC and same hardware. Good that

clarified this point.

If so, it's most likely a pure software problem. Are you running special kernel drivers like Wireshark USB capture or any other software that might affect USB operation. Also did you verify that Quartus 20.1 is using the recent JTAG server instance, can be checked in Services under Altera JTAG server or by executing jtagconfig in cmd window.

I would try a fresh install of recent Quartus standalone programmer which includes Signaltap and load your present Signaltap file from there.

Presume you are using genuine USB Blaster (Intel/Altera/Terasic).