I posted a gist [0] sorry it's not really made for public scrutiny, it's an old pet project clock, a video of most of that code is still there: https://plus.google.com/+MichelPollet/posts/ARDMrY4jSxp

That code does timer, radio clock decoding, scrolling, blinking and all that using multiple 'protothreads'. As you can see the main loop sleep() and wait for a timer interrupt (or anything) to fire to wake up, so it's not even running most of the time; only when the 'tick' timer fires.

[0] https://gist.github.com/buserror/9407adb6d52153e16caad5e8a08...