Watching YouTube it looked like left/right/open/close were pretty absolute commands, but that up and down varied (there are two steps in Gyromite but more than two for StackUp). So those two at least probably include some kind of distance or step command.
I don't have StackUp, but I took a look at Gyromite's signals via emulation, and these are the patterns I get. 0 is a black screen, 1 is a green screen (although any bright color will probably work, the color indexes used in Gyromite are $0F for black and $2A for green).
I believe it is setting the color every vertical blank (ie 60fps), which would be simplest. It may be 30fps (every other blank) just to accomodate TV frames.
I don't have a ROB and I don't know if anyone reading this thread can test code, so I didn't try to write any, but this is what I get from a quick look.
First, the screen should be blank during the flash cycle - either clear the screen or set the blanking bit (if the NES has that!) Use black for 0s and bright green for 1s, and change every vertical blank.
There seems to be a 5 frame sync signal: 00010 - The number of leading zeros is probably unimportant, and it's only important that there be at least three blank pulses before the 1, this is probably equivalent to a start bit. I would expect you could write a routine that generically shifts out 8 bits and so use 00000010 safely.
Next is 8 bits of control data. I don't know if the up and down contain data or are otherwise different in Stack Up, these are what Gyromite uses (or do I remember wrong and Gyromite has 5 or 6 stop points for up and down too??):
UP: 10111011
DOWN: 11111011
LEFT: 10111010
RIGHT:11101010
CLOSE:10111110
OPEN: 11101110
Finally, always end with a single frame of black (0).
If anyone wants to try this out, I'd love to hear if it works. If anyone can run custom software against the ROB (maybe with a flash cart or test with an emulator?), I could try to whip something up real quick.
