Using JTAG for FPGA through FTDI chip in Basys 3

[Salvador G]

Hi everyone!

I am trying to program a debugger for RISCV microcontroller architecture embedded in FPGA, using the JTAG debugging.

For that, I want to use the JTAG port in my FPGA, but I cannot configure the FTDI Chip contained in the evaluation board to send JTAG chains to the FPGA.

Now I'm using  a C232HM FTDI cable connected to the J5 port, which contains a similar chip that the Basys 3 contains, and they should be configured similarly.

 

Using the AN_129 of FTDI I can detect the digilent devices (it's a single device, but with two channels) but I cannot configure MPSSE on them to send JTAG commands through the USB controller to JTAG in FPGA.

 

Do anyone know any configuration that I'm probably missing or if the FTDI chip contained in Basys 3 have that feature cut for any reason?

 

Sorry if this topic is already solved, I cannot find anything about that in forums and I'm a little bit lost with this.

 

Thanks in advance!

[JColvin]

Hi @Salvador G,

The onboard FTDI chip on the Basys 3 allows for JTAG communication; that is how it can configure the FPGA: https://digilent.com/reference/programmable-logic/basys-3/reference-manual#usb-uart_bridge_serial_port.

I do not know the specifics of your setup, but the Adept SDK (part of the Adept download: https://digilent.com/reference/software/adept/start) has a JTAG subsection that might be of help to you.

Let me know if you have any questions.

Thanks,
JColvin

[Salvador G]

Hi @JColvin,

Thanks for your quick answer, I downloaded the Adept SDK and I tested with the JTAG example to obtain the FPGA Device ID and it works, I didn't know about the existence of that SDK.

I'll perform some tests to follow my purpose and if I have any trouble I'll create a post in the corresponding section.

 

Thanks a lot!

Salvador