DPTI: Synchronous Interface and JTAG

[wallento]

Hi everyone,

I have started using the Nexys Video board and have a question about DPTI before starting: I understand that when channel A is used in synchronous FT245 mode in the FT2232 chip that channel B is switched off. Is that correct? That would mean I cannout use synchronous DPTI in parallel with Vivado debugging, right?

One alternative is using asynchronous mode apparently, but I am also wondering if I could connect my debug cable to the unequipped JTAG port instead? Anyone tried that setup?

Cheers,

Stefan

[jpeyron]

Hi @wallento,

I have reached out to a more experienced engineer for some input into this thread.

cheers,

Jon

[malexander]

Hi Stefan,

That's correct you can't use the on-board JTAG programmer/debugger while using the synchronous DPTI interface. However, it should be possible to connect an external JTAG cable, such as the JTAG-HS2, to header J17 and use that to access the scan chain while simultaneously using DPTI. I haven't tried this myself but the on-board JTAG interface has tri-state buffers and is held in tri-state when not enabled so it should work.

Thanks,
Michael