Any chance you can document or explain the code ?
I've have a read through and think I see whats going on but would like to be sure.
I'd like to make use of this instead of using tlc5940s (too expensive, hard to get hold of and currently in my prototype flickering madly) but might have to squeeze a few more 74595s into it for my project. I assume the quantity that it can drive is down to the time taken to shift the data out within each interrupt ?