3.7. Expansion headers

The Balboa 32U4 control board has expansion headers on its four edges that break out several free general-purpose I/O lines from the ATmega32U4 microcontroller along with a few power pins. Various power inputs, outputs, and control pins are also accessible elsewhere on the board. The following diagrams identify the locations of these pins and the hardware associated with them; they are also available as a printable PDF (2MB pdf). For more information about the ATmega32U4 microcontroller and its peripherals, see Atmel’s ATmega32U4 documentation.

Pinout diagram of the Balboa 32U4 control board (ATmega32U4 pinout and peripherals).

Pinout diagram of the Balboa 32U4 control board (Raspberry Pi pinout and peripherals, level shifter, and board power control).

Power distribution diagram of the Balboa 32U4 control board.