This code is uploaded to an AVR attiny85 mcu (84 works too) to generate servo control signals based on an analog input. I like this concept because you can now easily make a small controller for servos and ESCs, and hide the tiny thing anywhere on your device!
I learned all I know (not much) from these folks:
http://www.kobakant.at/DIY/?p=3742 http://highlowtech.org/?p=1695 http://highlowtech.org/?p=1706
https://maxembedded.wordpress.com/2011/06/22/introduction-to-avr-timers/
http://www.nongnu.org/avr-libc/user-manual/group__avr__interrupts.html http://www.avrfreaks.net/forum/tut-newbies-guide-avr-interrupts?page=all