It's an ARM Cortex M3 based processor, the STMP103...something or other by ST Microelectronics. It's a neat little thing, but for the most part I have to do everything from scratch (except PWM, although it's horrifying how complex the code to someone who is used to webbotlib :-P)
On the upside, 1/2 of the counts is all I need, really, since position control can be inaccurate. I've heard tales of the STM* controllers having encoder inputs on them, although I haven't the foggiest clue of how to use them. They are, shall we say, poorly documented :-)
MIKE