Is the schematic for the ReSpeaker Microphone Array v3.1 available please? Specifically the one from the enclosed version with USB and headphone jack on the underside of the board.
There are a number of test pads on the same side as the connectors which I’d like to identify, looking at the schematic for the v3.0 there are a lot of differences so I don’t want to trust that one with my project.
Mostly it’s USB, audio, and ideally an i2s output I’d like to get access to.