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robotics - electronics - machining
  Monday September 25th 2017 09:25:43 PM

USB Breakout


New USB Breakout boards available in limited quantity.



Reference Board layout.



Description

The USB Breakout board as the name indicates is a DIP breakout board for the Atmel ATMEGA32U2 USB chips that are not available in DIP form. It simplifies developement of USB code and devices for this chip.

  • Microcontroller option: ATMega32U2
  • Switch selectable power from USB-VBUS or breadboard
  • One button program option (Remove R4 if not desired)
  • Accessible USB D+, D- lines
  • Preprogrammed Atmel bootloader
  • Use Atmel's FLIP or DFU Programmer to load programs over the USB Port
  • Compatible with LUFA
  • Compatible with PSGroove
avr-libc bug

Older device definition files may cause a compilation error when building LUFA projects for the Atmega32U2. You will get an error about clock_div_1 not being set and missing clock_prescale_set

To correct this, edit avr/include/avr/power.h by hand. Insert the following line:

|| defined(__AVR_ATmega32U2__) \

into power.h. Look for a long list of similar definitions around line 1300 of the file. The two missing symbols will now be defined and Atmega32U2 projects will compile. Thanks to Dean Camera for this solution.

DFU-programmer bug

DFU-programmer is a free alternative to Atmel's Flip tool. Unfortunately, there is no support in it for atmega32u2 in the current binary release of this tool. However, there is support in the latest SVN version. Hopefully DFU programmer will be updated soon.

$ svn co https://dfu-programmer.svn.sourceforge.net/svnroot/dfu-programmer/trunk/ dfu-programmer
$ cd dfu-programmer/dfu-programmer
$ ./bootstrap.sh
$ ./configure
$ make

Thanks to The Portland Dorkbots for this solution.



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