Xilinx/Digilent ft2232h interface

[sarah90]

I'm in the process of designing my own spartan-6 fpga board. I want to include a jtag-option that is compatible with the xilinx tools, so options like chipscope/sdk can be used. However xilinx has not opened up the plugin interface to their tools.

Only digilent boards and cables are supported next to xilinx own tools. The latest digilent boards are using the ftdi ft2232h chip for their jtag interface and I understood from the web that it should not be difficult to mimic the digilent interface, as the Pipistrello fpga board is doing that out of the box.

I have been experimenting with a ft2232h chip for some time now, but I have not been able to get it recognized by the xilinx (ise 14.7) tools as a digilent interface. I suspect it is related to the configuration data of the ft2232h (located in the eeprom).

I was wondering if someone has done something similar and/or has some tips. What also would be very useful is a dump of the eeprom data of a digilent board and/or the pipistrello (using ftdi's ft-prog tool).

Any help is appreciated!

[bigtoy]

I believe you're on the right track. Once upon a time I built a clone of a proprietary JTAG programmer (nothing to do with FPGAs) that also used an FDTI chip. Copying the hardware was easy, but I also needed to read out the EEPROM and write it into my board to get it to work. In my case I had one of the original JTAG programmers so I was able to do that. And then my clone worked fine. So I think you're on the right track.

[sarah90]

I found this Russian forum that contains a lot of information on this exact subject: https://electronix.ru/forum/index.php?showtopic=114633

Software on that forum is able to reprogram the user part in the eeprom and gets my ft2232h recognised as a Digilent JTAG-HS2. Now I have some trouble to get it fully working on linux, but that may be some silly linux compatibility issue.