Quoted from futurepinhead:

GTech13 said:The display is controlled by an ATmega168. It is multiplex by rows. There are 5 shift register drivers (CAT4008) driving the columns (cathodes) which have built in current regulation and then there are 7 PNP transistors switching each row successively. So the process is to send out 5 bytes which says which LEDs to turn on for whichever row and to enable that row via its PNP. Then another 5 bytes for the next row and change to the next PNP. Do it 7 times then start over. And then do that process really fast so it looks like the whole thing is on. I need to make the last 3 registers and then comes trying to make the thing scroll horizontally and vertically.
You lost me after "The display is controlled by..."