Having a think about a suitable test to confirm whether or not the BOB is being changed by Mach 3. If I took a red LED and a 150ohm resistor and connected them between the 5V supply on the BOB and pin 3, the x axis Dir, would it light when the axis was moving on one direction and not in the other? I was under the impression the BOB would give a High output for one direction on the motor and a Low output for the other?

Many thanks