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Hello Dennis,
from your report, I guess that's a special problem related to your hardware and most likely can't be identified without examining all hardware details (supply voltages, circuitry at all pins affecting configuration). Also an assembly issue or part defect should be considered. I assume, that AS and JTAG configuration actually was using an identical compiled design (sounds obvious, but ain't necessarily so...).
However, I didn't experience a similar problem with a lot of Cyclone II designs during the last years. If it's caused by JTAG signal quality (particularly ringing TCK), as other reports suggest, this should be seen watching the respective signals.
Regards,
Frank
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Hi Frank,
Thanks for the reply.
For hardware wise related issues, several attempts had been applied through. For your information, all the PCBs were fabricated at the same time by 1 vendor (means same batch). I also tried to isolate all the supply voltage circuitry and pumped in external supply but still getting the same resuly. I even assembly the board with the mere basic FPGA and JTAG circuitry only with external supply.
The weird situation is:
2PCBs have no problem on JTAG and AS.
3PCBs have no problem on AS but JTAG.
In conclusion, all the AS is working fine but not JTAG on 3 PCBs. So i cant relate the problems on boards/assembly/chips issue.
I'll try to capture and compare the screenshot for all the JTAG signals on working PCB vs non-working PCB.
Regards,
Dennis
Honored Contributor
