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Visitor emy
Visitor
445 Views
Registered: ‎01-15-2019

FPGA is not detected by Hardware Manager (USB)

There are three FPGAs which are connected in JTAG chain.There is an issue with third FPGA. On adding third FPGA none of the devices are detected on JTAG. If we remove third FPGA from the chain, other two FPGAs are detected.Observations are given below for 

Case 1 : Inserting all the FPGAs on chain

Case 2 : Third FPGA is removed from the chain

 

  • For case 1, there is discontinuity in JTAG clock and TMS signal
  • Both the signals are continuous.
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5 Replies
Adventurer
Adventurer
428 Views
Registered: ‎12-16-2018

Re: FPGA is not detected by Hardware Manager (USB)

Hi

This issue could be related with the JTAG signals. Check in the third FPGA the JTAG signals( voltage level, waveform). Let me know if this help you.

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Adventurer
Adventurer
408 Views
Registered: ‎12-16-2018

Re: FPGA is not detected by Hardware Manager (USB)

Try this:

Insert the third FPGA and be sure that the JTAG signals aren't short-circuit.

Check that there's not a low voltage level in the JTAG signals when you connect the third FPGA, check also the JTAG waveform. 

If you can share a screenshot of the JTAG signals better

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Visitor emy
Visitor
391 Views
Registered: ‎01-15-2019

Re: FPGA is not detected by Hardware Manager (USB)

Hi,

Checked the voltage level. They all are having expected voltage levels, i.e 1.8V.

  I have attached the screenshot of  JTAG signals below :

TCK ON UNLOAD 12.pngWaveform of TCK signal without inserting 3rd FPGATCK_ON LOADING 12.pngWaveform of TCK signal inserting 3rd FPGATMS_ON LOADING 12.pngWaveform of TMS signal on inserting 3rd FPGATMS_ON UNLOADING 12.pngWaveform of TMS signal without inserting 3rd FPGA

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Adventurer
Adventurer
381 Views
Registered: ‎12-16-2018

Re: FPGA is not detected by Hardware Manager (USB)

Hi

I see the screenshots and the clock signal exhibit some distortion. If you can, take a screenshot of the TDI and TDO signals also. Can you replace the third FPGA by another or interchange this FPGA with another that you are sure that is OK? ESD could be a reason of this problem.

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Xilinx Employee
Xilinx Employee
333 Views
Registered: ‎06-21-2018

Re: FPGA is not detected by Hardware Manager (USB)

Hi emy,

Are all 3 Xilinx devices?

If not, please take a look at this Answer Record:
https://www.xilinx.com/support/answers/61312.html

Let us know what's in your board, maybe a diagram of your JTAG chain?

Thanks,
Andres

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