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sipeed / TangNano-4K-example

TangNano-4K-example project
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horizontal timing error #3

Open Popolon opened 2 years ago

Popolon commented 2 years ago

It looks like there is a typo in video_top.v line 301, on the value and the comment at the syn_gen syn_gen_inst function parameters

    .I_h_sync    (16'd40          ),// 16'd128   // 16'd136   // 16'd40

After displaying the video in full size (1280x720), I still had the diagonal line instead of vertical one. default demo

I changed it by 140 instead of 40:

    .I_h_sync    (16'd140         ),// 16'd128   // 16'd136   // 16'd140

And now it works, the lines are vertical (I made some modification tests with the demo, mixing grid demo and colors/gray bars demos): Full screen demo

Popolon commented 2 years ago

Strangly the previous value of 16'd'40 must be keep as is in testpattern_inst, line 148 else there will be again a diagonal display

Popolon commented 2 years ago

Strangly, after new test I can't get again my correction working. I also noticed than with this code, the HDMI output doesn't work with a HDMI to USB video acquisition dongle I have. By exchanging on a Sipeed channel. Someone that worked on HDMI on several FPGA, said me he added Tang Nano 4K. And it work perfectly, even with my HDMI to USB dongle. Hope his work can be reused here and on other people that want to work with this board:

https://github.com/splinedrive/my_hdmi_device