images are CC BY-NC-SA 3.0
Description: The ATMega 32U4 is an 8-bit AVR microcontroller featuring 32KB self-programming flash program memory, 2.5KB SRAM, 1KB EEPROM and a 12-channel 10-bit A/D-converter. It even has on-chip USB 2.0. You might recognize it from our Pro Micro development boards as well as the Arduino Leonardo.
This breakout 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, which 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.
When you power the board on, your application will run by default. If there's no application in program memory then the bootloader will run. If you have an application already on the IC and you want to reprogram, simply press the on-board reset button and 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.