Add documentation of the 22-pin camera connector

[kbingham]

The Camera Hardware schematics (https://www.raspberrypi.com/documentation/accessories/camera.html#schematics) shows the pinout of the 15 pin camera connector, but not the 22 pin version used.

Could https://github.com/raspberrypi/documentation/blob/develop/documentation/asciidoc/accessories/camera/camera_hardware.adoc be updated to also reference the 22 pin connector pin-out please? (While this pinout is easy to find online, I would rather reference Raspberry Pi documentation than an external vendor)

[aallan]

Ping @davidplowman and @naushir on this one.

[lurch]

Not exactly what you're looking for, but there's also https://datasheets.raspberrypi.com/cmcda/cmcda-schematics.pdf and https://datasheets.raspberrypi.com/cmcda/RPi-CMCDA-1P1.zip

[naushir]

Agree, the 22pin connector should be added here.

[aallan]

So I'm going to get the design team to work this diagram (and the existing 15-pin diagram) over so they look the same, and just a bit nicer as part of general "improve the quality of the diagrams and photographs in the documentation" push. But for reference here's the 22-pin connector.

[lurch]

I'm guessing that's one of the MIPI CSI/DSI transceivers on the Pi 5? Just for the sake of completeness, do we also want the pinout of the 22-pin camera connector on the Pi Zero / Zero W / Zero 2 W ?

[kbingham]

https://datasheets.raspberrypi.com/cmcda/cmcda-schematics.pdf seems to show a different 22-pin pinout than the diagram above. Do we have different pinouts for connectors that are physically the same across the range of Pi products? (That surprises me)

I.e. - I expect to see IO1 (PowerEn) on pin17 on a 22 pin connector?

[lurch]

It looks like the numbering-scheme in the CMCDA schematics is simply "reversed" when compared to the diagram above? E.g. the diagram above has 3.3V on pin 1 and GND on pin 22, whereas the CMCDA schematic has 3.3V on pin 22 and GND on pin 1. And when you take that into account, the pinouts do seem consistent?

[kbingham]

Yes, indeed - it does look reversed. Does that mean that cables on Pi5 are in any way reversed? Having used cameras on the Pi5 already - I expect not - but maybe that's something to clarify in the documentation.

I can confirm however that adding a camera to a Pi5 with a reversed cable (Terrifyingly I have one, and hit this by accident) will cause the Pi5 to fail to boot up at all (not even to the bootloader) so it gets pretty obvious quite quickly if it's wrong. (Hence why I want to be /very/ sure about which is pin 1)

[lurch]

I think we'd only recommend using official Raspberry Pi cables, which obviously don't have this problem 😉

[kbingham]

I think we'd only recommend using official Raspberry Pi cables, which obviously don't have this problem 😉

Tell that to the pile of mipi cables I have on my desk ;-) haha