Caterina Bootloader

Bootloader Installation

In order to use the Atmega32U4 with the Arduino SDK, the Atmel bootloader that is factory-default has to be replaced. In our setup, we use the Arduino Leonardo bootloader. It is called 'Caterina' and can be found in the Arduino directory:


Flash the bootloader to the chip using AVRDude:

avrdude -p m32U4 -P /dev/ttyS0 -U flash:w:Caterina-Leonardo.hex

After that, set the correct fusebits:

avrdude -p m32U4 -P /dev/ttyS0 -U lfuse:w:0xe0:m -U hfuse:w:0xd8:m -U efuse:w:0xcb:m

Try everything out:

avrdude -p m32U4 -P /dev/ttyS0 -nv

And you should get:

avrdude: safemode: lfuse reads as E0
avrdude: safemode: hfuse reads as D8
avrdude: safemode: efuse reads as CB

Now start the Arduino IDE. Select 'Arduino Leonardo' as your board and the matching '/dev/ttyACMn' port as port.