I bought, on spec, a bi-color 8x8 led matrix from sparkfun. i've been poking at it using the arduino's pins to drive the anodes(thru resistors) and a 3->8 decoder chip to select the row(cathode).
i know there are other arrangements with shift registers and drivers but do you always end up with a 1/8 duty cycle? i.e. you scan down the rows lighting the appropriate columns for that row (or vice versa I guess)? What about their serial modules?