I was thinking about the expansion port and that it might be nice to put an SD card into the keyboardio. We could store layouts or…in the keyboardio. Is this even something that is possible before I start going down that rabbit hole?
A quick search suggests that the Atmega32U4 is capable of supporting an SD card reader via SPI. Not sure how many pins that may need, etc. But from a firmware point of view, it should work.
But this is just a hunch, with minimal understanding of the required hardware mods.
It is a four wire interface. I think this could be a nice addition. It could just expand our memory for the system.