Step + Direction?

I would like to run a stepper using one pin for direction, and another pin for step pulse (can’t use the existing stepper lib for misc reasons)… Anyway - can I setup an H Bridge to do that? I ran across this Circuit that looks promising… But I am not positive what A and B are for (even though there is a description for them, it confuses my small brain). Also - would it be useful if I added this functionality to the existing Stepper lib?

http://www.acroname.com/examples/10047/10047.html

If you already have an H-bridge setup (or whatever) to run a stepper motor, then the easiest way to turn it into a step/direction interface is with a shift register. You’ll need a bi-directional parallel-out shift register. Instead of hooking the h-bridge control lines to the controller, you hook them to the outputs of the shift register. You’ll have to configure it to do circular shifts. Then the clock and direction pins of the shift register are hooked to the controller.

Unless you are controlling multiple steppers, then it’s hardly worth the effort. You’d be better off implementing functions in software that emulate the behavior you want.

$0.02