How do the EyasSAT modules communicate?

The primary means of communications between the microprocessor in the C&DH modules and the other modules is an SPI bus.

The C&DH acts as the bus master, the modules are slaves. Chip select lines are assigned to each module.

Chip select lines are also reserved for up to three experiment boards that may be designed/built/used by owners and added to the EyasSAT stack.