HDMI on custom iMX8MP board


I have a custom PCB for my iMX8MP module, schematic is attached above, when I put my module into the Dahlia dev board, I get some HDMI output on the monitor.

Could anybody advice me where I went wrong in my schematic? I also tried connecting the CEC pin from connector to the IC with a pullup to 3v3, no luck so far!

Dear @eoin_oc1, hope you’re doing good.

Have you tried connecting pin 23 of the TPD12S520 to pin 13 of the X37 like on the example here:
image
Reference: https://www.ti.com/lit/ds/symlink/tpd12s520.pdf?ts=1656434395270

Best regards,

I have tried this, with a 27k pullup to 3.3, no luck.

Is the HDMI chip just a dumb translator, or does Linux need to have knowledge of this particular chip in the device tree?

Dear @eoin_oc1,

Our Hardware expert is currently sick and once he comes back he’ll guide you properly.

Best regards,

I have since fixed this issue, I should be using the TPD12S521 and not the 520, 520 for HDMI RX ports, 521 for TX ports

Glad you could solve it!