ATMEGA32U4 Breakout by Sparkfun

This Atmega32U4 breakout board is designed for people who are interested in programming outside of the Arduino IDE in order to take advantage of lower-level programming capabilities. The board comes pre-loaded with the LUFA CDC bootloader. This allows you to build your code with WinAVR and then program the chip through the USB interface using the program AVRDUDE and without using an external hardware programmer.

The ATMega 32U4 is an 8-bit AVR microcontroller featuring 32KB self-programming flash program memory. Plus it features 2.5KB SRAM, 1KB EEPROM, and a 12-channel 10-bit A/D-converter. It even has an on-chip USB 2.0. You might recognize it from our Pro Micro development boards as well as the Arduino Leonardo.

The application will run by default when the board is powered on. If there's no application in program memory then the bootloader will run. If you have an application already on the IC and want to reprogram, simply press the on-board reset button. The bootloader will run for 7 seconds to allow time for programming.

The first time you plug in your board, Windows will ask for a driver. Install the INF file below and the board should enumerate as a COM port.

Each pin on the breakout board is labeled with the AVR pin name including the port letter (PB0, PF6, etc.) to make prototyping a little easier. This is a great board for anyone who is thinking about making the transition from Arduino to AVR C. Check out the Github repository for updated example code, the bootloader source and build files, and additional programming information.