Modifying BaseOverlay firmware of RFSoC 4x2 is not working at all

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1

Dear all,

I am using PYNQ version v3.0.1, RFSoC 4x2 with Vivado 2022.2.
The BaseOverlay version has been tested with jupyter notebooks in PYNQ.
I tried to modify some of the RF DC configurations manually in Vivado for custom purpose, but none of them is working. I am sure that both bitstream and hwh files are newly generated and put in the PYNQ system.

  1. Sampling rate: The default rate is 4.9152 Gsps. I tried to change to lower rate and re-compile to make bitstream, but somehow the rate looks not changed?
  2. Refclk controlled by init_clk() in pynq: Only the default value for LMX (491.52 MHz) can be configured. If I specify other value for LMX in init_clk(), PYNQ must be crashed, or the clock in FPGA is not driven at all.
  3. NCO/mixer freq: For both TX and RX, I think their NCO/mixer freq can be specified in either Vivado RF DC or in PYNQ?
  • By default, mixer freq +1228.8 MHz for TX and -1228.8 MHz for RX. In PYNQ, TX freq can be updated and we can see the FFT spectrum is also changed due to that. But no matter how RX freq is changed to different value, the FFT spectrum remains the same.
  • If I first changed the NCO freq in Vivado’s RF DC for RX and re-compiled, the test result remains the same: the FFT spectrum is not shifted at all.

That’s basically all from my test. Somehow none of the changes in the configuration is working.
If one would like to make their own custom configurations (in sampling rate, refclk, NCO/mixer freq, etc) from the BaseOverlay Vivado project and to use it in PYNQ framework, is there any instruction to follow?

Thank you in advance.

2

I’ve been working on this issue as well. Strath SDR has a spectrum analyzer (GitHub - strath-sdr/rfsoc_sam: RFSoC Spectrum Analyser Module on PYNQ.) that allows for custom receiver mixing and decimation that appears to work quite well, but there’s no time-domain sampling IP or code implemented.

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Thank you. I tried to clone it and generate Vivado project, but somehow tcl script always failed to be completed due to some error message.

4

Hi. Let me label your reply as solution. I have cloned the repository and built the Vivado project. However, there is problem while running pip3 inside pynq. I think it’s better to be separated into another question.

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