I'm trying to make a fully configurable stepper motor controller by directly driving the H-bridges with the MCU, like an Atmel Atmega or other MCU, and use current feedback with the built in ADC, while using the PWM to create a current feedback loop (the ADC would measure across a sense resistor).
I'm trying to get the basics down of what is required to accomplish this. I need to be able to support microstepping as well. I've been looking at the datasheets of the Allegro and TI stepper controller IC's, and have a basic idea of what it needs to do, but the implementation confuses me a bit. I can't find any other projects that accomplish this. It seems that nobody else uses microstepping, or nobody uses a current feedback loop.
Are there any open source projects that accomplish this task? If so, where can I find the source code and schematics of these projects?