Burning ItsyBitsy 32u4 Bootloader
I bought 22x Adafruit ItsyBitsy 32u4 5v boards this week. Two of them didn’t identify when plugged in, instead registering as an error in Device Manager (I had a
libusb-win32 devices device called
I thought maybe the bootloader was the issue. Here’s how to burn it using an Arduino Uno as an intermediary.
How to burn the bootloader
- Arduino Uno
- Arduino IDE
- WinAVR installed
- Adafruit ItsyBitsy 32u4 5v
- Male->Female jumper cables
How to burn
Arduino as ISPsketch from the
Examples > ArduinoISPfolder in the IDE.
Wire Arduino Uno to the ItsyBitsy as follows:
Arduino -> ItsyBitsy 5V -> 5V GND -> GND 10 -> RST 11 -> MOSI 12 -> MISO 13 -> SCK
Download the Caterina bootloader for ItsyBitsy 32u4 5v from Adafruit website
On the command line, set the fuses for programming with:
avrdude -c avrisp -P COM9 -b 19200 -p m32u4 -U lfuse:r:low_fuse_val.hex:h -U hfuse:r:high_fuse_val.hex:h
Then burn the bootloader!
avrdude -c avrisp -P COM9 -b 19200 -p m32u4 -U flash:w:Caterina_itsybitsy5V.hex
In theory, its also possible to use the Arduino IDE to do this, but I didn’t have much success (it worked once, then gave me repeated errors).