Hello Kevin,
I’m about to embark on a very similar project, except it is just 6 MIC5841’s all on 1 board. I am planning to buy 4 channel logic level shifters, there are several marketed by the people selling boards for the RPi. SparkFun do the BOB-12009 which DigiKey also sell. The idea is to drive them directly from the Pi but I can’t see any reason why they could not be used between boards as well. They will output a signal level which is set by a reference pin, 5V in our case.
I’m not a very experienced programmer - would you be happy to explain how the code works that drives the GPIO pins for the 4 lines which the 5841 needs?
Thanks,
Thomas.