The symptom of my problem is that the board appears to work just fine without motors connected, i.e. red & green LEDs light up as expected fwd/reverse, both channels.
But when I connect motors to them, the LEDs don’t light up any more. (yes I power down first, and can swap repeatedly between ‘working’ and non-working leds, by connecting/disconnecting motors.
I’ve confirmed there is nothing wrong with the hardware, I can run the demo program and it drives 2 motors fine. But in my application I now want to use only 1 brushed motor, plus one stepper motor, which I’m driving with a A4988 breakout board on another shield. Presumably I’ve got some conflict with pin allocations, with the VHN5019 library fighting me for some pin, since. But I can’t figure out why connecting the motors ‘turns the leds off’.
thanks in advance