I'm working on a new driver board based on a Atmel's AVR's (single chip micro) for the open source forum here. Long term intent is to have a low cost DIY three axis board, that will also have the pport connection and interface for limit switch and spindle. Attached is a grapic of a one axis board layout and schematic for software development. I doubt if I can get to doing an this actual board for several month's. If somebody would be willing to etch or mill one for a minimal fee, I could get to work on firmware.
Or if somebody want to do some code, or.........
The Attiny2313 is fast enough to handle a simple edge filter to make the input filter circuit on my other boards unnecessary. It is also inexpensive. It should be able to handle half step as well as full steps simply. The 3 axis board would have three of them.
Cost wise the 2313 is about $2.25 and the fets show are about $1.50 each. That adds up to a 3 axis board that could probably be built for under $45 worth of parts.
Phil