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lowRISC / opentitan

OpenTitan: Open source silicon root of trust
https://www.opentitan.org
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connect two nexys video FPGA board through PMOD connector to test UART/SPI/I2C #8178

Closed nicolast0604 closed 2 years ago

nicolast0604 commented 3 years ago

Hi All I would like to test the UART/SPI/I2C of Earl Grey. I noticed there are PMOD and FMC on the Nexys Video FPGA baord. Can I connect two nexys video FPGA through PMOD and test the UART/SPI/I2C with for host/device mode.

If this is possible, is there any suggestion for how to connect it? what is the 4 PMOD(X12) nodes mapping to the SOC pinmux/pinout?

Best Regards Nicolas

msfschaffner commented 2 years ago

Hi @nicolast0604 and apologies for the very late reply.

The NexysVideo FPGA board is unfortunately not supported anymore due to the system size. If you wish, you can try to bring up a stripped down version, similar to the experimental toplevel top_englishbreakfast for the CW305 board.

Otherwise I would recommend using the main supported CW310 FPGA board.

The pinmux to pinout mapping can be found here, together with the software constant names that would be needed: https://docs.opentitan.org/hw/ip/pinmux/doc/#pinout-and-pinmux-mapping

Together with the XDC file you should be able to infer the mapping onto board headers: https://github.com/lowRISC/opentitan/blob/master/hw/top_earlgrey/data/pins_cw310.xdc

Note that there is an upcoming PR that will break out more pins onto the headers on the CW310 board: https://github.com/lowRISC/opentitan/pull/13818

I would probably go for UART first as that is the easiest interface to bring up in such a test.

msfschaffner commented 2 years ago

I am closing this for now, but please feel free to reopen if you have more questions.