CAN bus
Connect two boards like the following:
Board A Board B CAN_H --- CAN_H CAN_L --- CAN_L GND ----- GND
Set up the boards by running the following on each of them:
# ip link set can0 up type can bitrate 125000
Then:
On board A:
# candump can0
On board B:
# cansend can0 500#1E.10.10