I in the planning/information gather stage.
I want to replace the guts of a robo dog with a raspberry pi 3. It seems to have 8 serial interfaces with 8 pins(not necessary all in use).
I am trying to figure out the minimal amount of additional circuitry necessary to communicate with each of the 8 parts.
My first though was to divvy the 20 GPIO pins. What is the fastest speed I could achieve? How bad would this be for CPU utilization?