Does the chip contain some kind of video generator built in, or is he bit-banging video? 32x29 with a 7x8 character cell means 3118080 pixels per screen. With no allowance for retrace overhead, that means between 5 and 6 clock cycles per pixel (I see a 16MHz crystal on the schematic)...not that difficult with a superscalar CPU core, but this is a microcontroller.... Of course, I could probably work this out from the code, but that would take a good deal of staring at the code. /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B