Crazy clock problems

It's not going spectacularly well.

The problem at the moment is accuracy. The clock is gaining about one extra hour in 8. That's just got to be a software bug of some sort. It's just inconceivable that a crystal oscillator could be 12.5% off, even if the loading caps aren't right.

I thought I found a fencepost error last night, but oddly that didn't seem to make a difference, and I'm not sure why not.

EDIT: Figured it out.

It was a different sort of fencepost. If you take two periods of 1/2 and double time and add them together, you get 5/2 - which is 20% fast. What you want to do is add 1/2 and 3/2 together to get 4/2, which is the right answer.

It turns out, however, that in my judgement the result is just a hair too subtle. So instead, I'm going with 1/3 time and 5/3 time. That works out nicely, since 5/3 time is 6 pulses out of 30, which is nice division.