Wednesday, November 6, 2013

HDMI breakout PCB

HDMI breakout pcb
This is probably only useful to a small handful of people, but if you're and engineer developing HDMI products that might include you.
For some work developing HDMI-compatible FPGA code, I needed to observe the control signals with a scope. So I built up this little breakout PCB. The high-speed video TMDS signals are routed directly through from one connector to the other. I tried to keep them equal length and as short as possible. Don't have any way to verify impedance and reflections, but it works ok on one TV with short HDMI cables.
The low speed (CEC, SCL, etc) signals are brought out to the header in the back in the photo. Jumpers allow the signals to pass through, or they can be disconnected to test and modify them.
The PCB is shared on OshPark. See  if you want to use this design. It uses standard HDMI female connectors, available from DigiKey and many other vendors. Soldering the fine-pitch surface mount pins on the connectors is a bit of a challenge. I tried soldering individual pins, but ended up using the flood it with solder and mop up the excess with solder-wick method.


Unknown said...

I ordered this board through OSHPARK. What shows in the pictures on this site appear to the jumpers for the low speed signals. However, on the board there is a CONN_5x2 edge connector. What part do you recommend using for that? Also, can you give the exact Digikey part you used for the connector?
Tim Dygert

Joe Rothweiler said...

Good to see someone found it useful.

I use a standard 5x2 pin header soldered to the edge connector. The specific one I used in the photo is 649-68021-210HLF from Mouser (

The HDMI connector is 649-10029449-001RLF, also from Mouser.


Joe Rothweiler said...

I added more info about the pinouts and schematic. See my blog post "HDMI Breakout Part 2" on Feb 5, 2014.