Hi mrdreambot,
I'm back in action.
My first activity has been to look at the signals at low level, and I've had a couple of surprises. I wrote an app for the Mega that just looks at the times between transitions on the signal line between the Meccabrain and the display module. I had to use the Mega as there is a LOT of data to be stored - upwards of 2000 items to get useful results.
I first ran the program looking at the start-up sequence - see the file. (I've deleted a lot of repeats to save space, but nothing of significance.) I can't see anywhere in there that is a true serial sequence of FF 00 FF 000 FF 00. There is also no serial transmission between the blank screen for startup and the default sequence. The different sequences for the various forms of the default follow on one from the other with no serial message between them, which is in line with what I see with the oscilloscope.
I also managed to get a printout for a change in display using the programming mode to go from LOL! to BYE. Again, there is no indication in the timing of any serial strings between the two.
I'm currently working on getting the Nano to go - so far I've managed to get a software serial port running with the 2 stop bits needed, and am looking at how to connect up the hardware.
LOL - BYE timimg.pdf (47.9 KB)
MAX face array startup timing.pdf (57.6 KB)