Hiya Tom H and kur40,
You actually want to measure clock and use that as a "standard" in your comm protocol, this way the ticks can be accurate in digital micro land ;). I'll try to dig up an example from yeeeeeeearssss ago, am just throwing out ideas for y'all for now :) latency and each particular circuits latency will always exist. Here we have a known proven structure so it should get narrowed down fairly quick. You can always use flip/flop(7407 style) to help "clean" the signal in your interface comm device. The old 160/8192 non standard crapola seemed like a biatch at the beginning too. Throw in some clock jitter with an unknown protocol and you can imagine the kinda crap i had to sift and figure out back in the day. You guys are well on your way :) It still and always will boil down to 8 bit ;)