i need to carry the signals from a Raspberry compute module to a camera module and vice versa. Since I need to place the camera around 4 foot away from the microComputer, and i want the connection to be sturdy, and I need to be able to connect and deconnect the camera hundreds of time, the flat ribbon cable that is "native" to Raspberry is not viable.
The signals/power that need to travel are:
- three differential pairs (For data and clock)
- 3V3 and GND
- 4 logic signals
All logic signals and differential pairs are bidirectional. Power goes from the compute module to the camera module, which is totally passive.
I've experimented with an HDMI cable, printing custom PCB connector adapters on both ends and it works perfectly even for longer distances (3m or so). It has been working for months, so the idea is working. They even sell commercial adapters for this. I've also experimented with HDMI <-> miniHDMI and it works also, but the connectors are too bulky and moreover I've not found a cable with both endings miniHDMI.
Now I am looking for a similar, commercially available cable, with small connectors and able to carry the data I need.
I've tried with a miniDP but, because of my ignorance, I've overlooked the problem of power on pin20, so I have to discard it.
Now I've thought about USB-C, but it seems too complicated, with much logic in the connectors, I don't know if they are suitable. And moreover it seems that there are 3 differential pairs, but not enough signals for my use (I could work with just 3 control signals instead of 4, or at the very worst I think I could make do even with 2)
It puzzles me the thing that pins are replicated top and bottom (so inserting either way is unimportant)..
P.S. At the moment I've experimented with using one of the "signal" channels to route 3V3. I've jury rigged the PCB at the end of the cable to pass the power to the 3V3 tracks. It seems to work. I just hope internally the signal strand is able to carry the power (even if amperage is quite low)