This book guides the reader through the ins and outs of learning to program microcontrollers using assembly language. It is simple enough for beginners, but will challenge experienced programmers. The book's content is available
here, and an additional chapter
here.
It features the Atmel AVR Butterfly board, a stand alone $20 microcontroller with an LCD display, joystick, speaker, RS-232,light and temperature sensors, and more. It is an ideal controller for many robotics and embedded projects.
Topics are illustrated by fully coded and commented programs with detailed explanations of their design and function.
All necessary support software and documentation for programming the Butterfly, including all source code in the book, is available for
download free on the internet.