LED4 should be labled "75%" and should be green
Created by: jadonk
This led is used at the battery 75% full indicator.
Ideally, there would be 50% and 100% indicators as well, but we seem to be out of I/O pins.
See https://github.com/beagleboard/capes/tree/master/beaglebone/Robotics that this cape replaces.