First draft of the HDMI ARC module PCB layout is done. All parts are on the top side, but I did have to use one wire jumper (for the "module enable" signal, very low speed so no problem). It's up on github.

I realised I could make the ARC chip (Explore EP91H0) function as either transmit or receive by adding a couple of resistors, so I did that. Might come in handy for testing (rather than risking damage to my far-too-expense TV, the only device I have that currently supports ARC).

I'm using the good old CS8416 for SPDIF to I2S conversion, because I still have one in my parts drawer from my last DAC project.

The Raspberry Pi adapter boards and backplane are apparently in transit. So, if I'm lucky they'll be here in a couple of weeks...

Next move: finish the layout of the ARC module (cuts & silkscreen). Might throw in a few guard traces around the high speed clocks if I remember to...