From HacDC Wiki
There's a lot of good information out there about programming micro-controllers, but I couldn't find a good, stepwise, lesson-based tutorial. Since a bunch of the HacDC folks are just learning their way around, I thought it'd be fun to put together a mini-course based on the Atmel AVR platform and GNU-GCC. The idea is to have each lesson doable in an hour or so
What follows is a mix of how-to and code snippets and peoples' experience walking through it all. If you're following along and want to contribute, feel free.
The Basics (take these in order):
AVR Lesson: Setup: Get a programmer, a chip, the software, and some parts
AVR Lesson: Output Pins I: Basic output and LED Blinky example
AVR Lesson: Output Pins II: Binary math and Cylon Eyes
AVR Lesson: Input Pins: Debouncing and Button-triggered Cylon Eyes
AVR Lesson: Timers: Clocks and how to use them.
AVR Lesson: Pulse-width Modulation: An easy way to get analog outputs. Dimming LEDs or Crossfading Cylon Eyes
AVR Lesson: Analog-digital Conversion: Automatical Dimming Night Light