Pinout AVRPi-32U4

All of the Raspberry Pi GPIO pins are broken out to this header.

For a detailed description of these pins, see: http://elinux.org/RPi_BCM2835_GPIOs

Some of the ATmega32U4 GPIO pins are broken out on this header.

Please note that some of the pins may also be connected to Raspberry Pi GPIO pins, depending on what jumpers are on the CONN header.

There are also power related pins on this header. Please note that the PI5V pin on this header is powered from the Raspberry Pi. If you're backpowering 5V to the Raspberry Pi through the PI5V pin, please take the necessary precautions.

The ATmega32U4 on the board is powered by the VCC pin. Put a jumper on either RPI/VIN or USB/VIN, depending on what source you want to use for the 3V3 voltage regulator to power VCC.

On the CONN header you can make direct connections from the ATmega32U4 to the RPI (USART, I2C, SPI, RST, HWB) using jumpers.

To program the ATmega32U4, put jumpers on 'MOSI-10', 'MISO-9', 'SCK-11' and 'RST-8'.

After programming is done you can do with the pins as you please (see RPI and AVR header).

To be able to communicate with the ATmega32U4 in 'minicom' or 'screen', put a jumper on 'RX-14' and 'TX-15'.

For faster communication than UART, jumper the appropriate pins and use the ATmega32U4 as an I2C or SPI slave (the Raspberry Pi can only be master).

On the ICSP header you can connect an external programmer to program the chip.

Do not connect a programmer when the AVRPi board is still on the Raspberry Pi! At least remove all the jumpers from the CONN header first, or (better) remove the board completely from the Pi.

Whatever you do, don't put jumpers on these header. Things won't break, but they won't work either.

All of the ATmega32U4 GPIO pins are broken out on this header.

Please note that some of the pins may also be connected to Raspberry Pi GPIO pins, depending on what jumpers are on the CONN header.