Hi,
Here is my work some years ago when I rebuilding a wrecked Roland PNC2300 CNC Engraver. It based on classic L297/298 with L6210 diode array. The interface can be via LPT port to PC or by a microcontroller on board, If parallel port is used then the microcontroller socket must be left empty. The board designed for a PIC18F452, but by piggy-backed the socket then other micro's can be used. It works nicely until now.
-ichan.