Claus Kuhnel 
AVR RISC Microcontroller Handbook [EPUB ebook] 

The AVR RISC Microcontroller Handbook is a comprehensive guide to designing with Atmel’s new controller family, which is designed to offer high speed and low power consumption at a lower cost. The main text is divided into three sections: hardware, which covers all internal peripherals; software, which covers programming and the instruction set; and tools, which explains using Atmel’s Assembler and Simulator (available on the Web) as well as IAR’s C compiler. – Practical guide for advanced hobbyists or design professionals- Development tools and code available on the Web