HDMI output signal issue on the Z2

Support
1

Hi!

I’m having trouble using the HDMI output on the Z2 board.
My test design consists of my little video timing generator, Digilent’s RGB2DVI IP core, and a clocking wizard that takes the 125 MHz input clock and generates the pixel and serializer clocks.

This works perfectly on my Z1 board at 720p resolution. On the Z2 my monitor just displays the image for half a second, then it loses the signal for 1-2 seconds, then it displays it again, and so on. I have tried lowering the resolution, but the result was the same.

I don’t have much experience with the PYNQ framework, but I have downloaded the image to see if the base overlay’s HDMI output works. I have tried the notebook that demonstrates connecting the input to the output. It worked fine although the bitstream loading and software initialization process took a very long time, and it took even longer to start it again once it was stopped.

Do you have any recommendations on making my HDMI design work on the Z2? I couldn’t find any difference between the two boards regarding the HDMI output.

2

Can you try switch the clock to one of the PS to PL clocks and see if this makes any difference?

Cathal

1 Like
3

Thank you, it works.
What could be causing this issue? Is the direct 125MHz clock input’s frequency less stable?

Tamas

4

On my Pynq Z2 the 125MHz clock isn’t stable unless I have the ethernet connected or a loopback plug inserted.