HDMI is now working on the Z7-Lite board!

After some weeks of reading the HDMI documentation, programming, debugging, some months of inactivity because I was very busy with my job, and after an active debugging session at Silly Venture 2K21 in Gdańsk, Poland, I finally got the HDMI output in working order on the Microphase Z7-Lite FPGA board.

A HDMI transmitter with the required functionality

The challenge was to address the HDMI port on a board that had no dedicated HDMI controller chip, so the controller had to be implemented in the FPGA logic. The previous board I was using, the Z-Turn board, has a nice sil9022a HDMI chip that takes RGB pixel data, horizontal and vertical sync, and audio as input, and produces the proper video output to the HDMI cable, whatever the image resolution, or the refresh rates. The challenge was to make something with similar functionality in VHDL. As I said in a previous post, there is another open source project that proposes an implementation of a HDMI source, but its functionality did not correspond to my needs: it has a fixed set of video modes, and it controls the source of pixel data, instead of having the video source control the HDMI.

Actually, this VHDL implementation of a HDMI transmitter should be generic enough for me to separate it and release it as an individual project in the near future. This should be able to help other people in their projects involving HDMI on many different FPGA boards.

So now we have everything we need to get zeST working on the Z7-Lite board.

Next steps

In the upcoming weeks and months I will be mostly busy with improving the compatibility of the hardware with the real ST.

Talk to you later!

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