It's a 12 bit up/down counter tied to a R2R precision ladder for a continuously variable, low noise analog output (through a 5V rail to rail OPA343 amplifier). Starting point is can be hardwired using the marked spots for each bit. (all bits have to be tied to 1 or 0, in any case) Button reset and interface reset. Two units can be daisy chained through a separate pin (wiring one to output the last counter signal and the next to input that signal onto the STEP pin) for a 2D raster scan, for example.

I use it to interface a laser cutting software to a CRT scope in XY mode. Other people want to drive laser mirrors, find your use! ^^