I am trying to gather some info about the M.2 connector.
My end goal is to add Wifi capabilities (e.g. using an Intel Pro Wireless M.2 card) to a Computer On Module system (iMX6, raspberry pi cm3, etc.).
I've been looking on Wikipedia and Google for info about M.2 connectors and all I have found is that M.2 connectors have different capabilities depending of the physical keying. And that Intel Pro Wireless cards use PCIe and USB bus (also some seem to use UART).
Is there somewhere a document giving the pin layout of the M.2 connector, in particular for A-E keyed cards?
Do the M.2 host must provide USB and PCIe or is it USB or PCIe ?