AVR Helper Library
The AVR Helper Library is a small collection of modules written in C that I have found useful while developing and prototyping Atmel AVR-based software. It includes a buffered USART module, buffered and unbuffered SPI modules, and some odds and ends like "gentle" EEPROM update functions, a thermistor temperature calculation function, and "endian" conversion functions.
The library builds for different AVR families which include the ATmega128, the ATmega103, the AT90S8515, the AT90S8535, and the AT90S4433. It should be relatively easy to modify the make files and source to build the libraries for other AVR microcontrollers.
I have released this code under the GNU Lesser General Public License with the hope that others might find it useful.