Reviving using avrdude – Pololu A-Star 32U4 User Manual
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8.2. Reviving using AVRDUDE
This section explains a special method for reviving an A-Star using the command-line utility
in case your usual method of programming is not working. AVRDUDE stands for “AVR
Downloader/UploaDEr”, and it is compatible with the A-Star bootloader.
If you have an A-Star 32U4 Micro, you should connect a
between the GND and RST pins to serve as a reset button. The A-Star 32U4 Minis have an on-board reset button
you can use. Alternatively, you can use a wire to temporarily connect GND and RST together instead of using a reset
button.
1. Connect the A-Star to your computer via USB.
2. Prepare the computer to show you a list of its virtual serial ports. If you are using Windows, this means you
should open the Device Manager. If you are on Linux or Mac OS X, this means you should open a Terminal and
type the command
ls /dev/tty*
but do not press enter until the board is in bootloader mode in the next step.
3. Press the reset button twice within 750 ms to make the AVR go into bootloader mode. You should see the
yellow LED fading in and out when the AVR is in bootloader mode. While it is in bootloader mode, quickly
look at the list of serial ports provided by your operating system in order to determine what port the bootloader
is assigned to.
4. Type the following command in your terminal and replace COM4 with the name of the bootloader’s serial
port, but do not press enter yet. This command will erase the malfunctioning program on the A-Star but preserve
the bootloader.
avrdude -c avr109 -p atmega32U4 -P COM4 -e
5. Press the reset button twice within 750 ms to make the AVR go into bootloader mode.
6. Quickly run the command you typed previously. The command needs to be run within 8 seconds of starting
the bootloader, or else the bootloader will exit and try to run the malfunctioning program again.
By following the instructions above, the malfunctioning program on the A-Star will be erased and the A-Star will stay
in bootloader mode indefinitely. You can now load another program onto it using the Arduino IDE or AVRDUDE.
Pololu A-Star 32U4 User’s Guide
© 2001–2014 Pololu Corporation
8. Reviving an unresponsive A-Star
Page 29 of 30