Dual USB-C split keyboard prototype
I redesigned the split keyboard controller to use two USB-C ports. The design allows for the controllers to be daisy chained with one another with one device on the end of the chain connected to the host. The device connected to the host uses USB 2.0. The rest of the devices use USB-C alternate modes to reconfigure some of the USB-C data lines to carry I2C for board-to-board communication.
Also the pins of the TRRS connector are shorted together to the adjacent pins when the cable is inserted and removed, which means its unsafe to plug/unplug the device while it is powered. I thought I could design around this, but I couldn’t think of a way to do so easily. Using USB-C avoids this issue.
A lot of the components in this design are probably unnecessary, so I should be able to shrink the form factor quite a bit.