April 9 2016
This project would have been easier to debug if I had used more leds, at least one on the A3967 STEP pins. However, these leds should then be removed from the production version.
The MTR_/RESET led should be inverted, ON when the signal is LOW.
I need more motors for testing. Since I don't yet have a specific application in mind, buying a bucket of used stepper motors might be the best option. It might be worth a trip to Halted Surplus on Monday.
Screw-down terminal blocks for the motor power would be nice, especially for the first boards.
I forgot the big filter caps on the motor supply line. This allows an unacceptable amount of reflected noise from the motor, resulting in glitchy motion as step signals are lost in the noise. This is most likely the reason why the motor stalls when I try to run it at any speed faster than a step every few milliseconds, when the driver is rated for 500K steps per second.
A prototype board should have plenty of test points, especially on the control lines (ie MTR_STEP).
The silk labels for the motor connectors should be larger and include the "R U K G" wire colors.