I would like to know how to connect DRV8825 to velleman k8055 card.
So far my experiment was not working. I connected +5v signal (pulsing from 0 to 5v) to STEP pin, +5v supply from k8055 to RESET pin and SLEEP pin, gnd from the k8055 to GND pin. I also connected 12V supply for motor,etc like you described with instructions.
What happens is that motor is shaking a little even without connection to STEP, when I give +5v pulse to STEP it starts to spin uncontrollable making half of the circle then few steps back and forward,etc