Direct JTAG programming doesn't work

[vnikolov@vnikolov.cz]

Hi!
I want to program my Alchitry Au+ directly using Xilinx Platform Cable USB II. I hope that this way I will be able to use live on-chip debugging in Xilinx Vivado.
But it doesn't work for me.   

I'm using Alchitry Br Prototype Element Board, which has pins for TDI, TDO, TCK and TMS. I connect Xilinx Cable to these four pins. Then I connect GND and +3.3V pins. I'm powering the board by a lab power supply using Raw +5V pin.

The Alchtiry Au+ seems to be alive (a configuration stored in flash runs OK). Status led on Xilinx Cable is green.
But Vivado Hardware Manager says that no board is connected.
(I know that the Xilinx Cable works. It operates without problem with this board.) 

What am I doing wrong?

Viktor


  20210925_194517 small.jpg (Size: 485.94 KB / Downloads: 22)

  Screenshot - 25.09.2021 , 19_51_26.png (Size: 22.82 KB / Downloads: 17)

  Screenshot - 25.09.2021 , 20_04_39.png (Size: 166.5 KB / Downloads: 14)

[alchitry]

I haven't dusted off my Platform Cable II since I created the Mojo, but I just hooked everything up to an Au+ and Au and it detected the FPGAs right off the bat.

Mine is the red version and the pinout looks slightly different (mirrored) but I can't imagine it matters.

I did power both of mine over the Au's USB port instead of via the Br board. My only thought is you might be creating some grounding issues between the platform cable and the bench power supply. The platform cable seems connect its ground to the USB ground.

I'm not sure what the difference in the cable is, but I connected both GND and PGND to the Au's ground. Connecting either of them made the FPGA show up though so I don't think this is necessarily the problem.