The AVR Helper Library is a small collection of modules written in C that I have found useful while developing and prototyping 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.
I have released this code under the GNU Lesser General Public License with the hope that others might find it useful.