atmel topic
AVR-Simulator
Atmega328 Simulator written in C#. [Proof of concept].
ArduRTOS
Real Time Operating System Lessons using Arduino and The FreeRTOS Kernel
fancontrol
Arduino Leonardo (ATmega32U4) PWM fan PID control
MicroCore
A light-weight Arduino hardware package for ATtiny13
MightyCore
Arduino hardware package for ATmega1284, ATmega644, ATmega324, ATmega324PB, ATmega164, ATmega32, ATmega16 and ATmega8535
MiniCore
Arduino hardware package for ATmega8, ATmega48, ATmega88, ATmega168, ATmega328 and ATmega328PB
kmk_firmware
Clackety Keyboards Powered by Python
Marlin
Marlin is an optimized firmware for RepRap 3D printers based on the Arduino platform. Many commercial 3D printers come with Marlin installed. Check with your vendor if you need source code for your sp...
qmk_toolbox
A Toolbox companion for QMK Firmware