avr-sim is a full featured software simulator for Atmel AVR microcontrollers.
It was primarily designed to simulate all current and hopefully future AVR microcontrollers.
It was designed to behave like the real chip as well as possible, this includes the core,
internal peripherals and the I/O pins. It is therefor possible to create external hardware
and tie them to the chip's pins and test the AVR microcontroller as you would in the real world.
The simulator can be tied with avr-gdb and supports typical debugging features like breakpoints,
disassembling, stepping, inspecting and changing memory, etc
It also allows tracing, analysis using scripts and facilitates in regression testing