Atmega32u4 breakout won't start uploaded code

[jcrood]

Hi all,

I've just received my Atmega32u4 breakout board and as a test I uploaded a simple "blink the boot led" program, with just about no result. No blinken lights for me. While uploading via avrdude through the bootloader went down without a hitch, after a reset and past the boot loader timeout, the little thing just sits there, doing nothing. After trying a few other small test programs with the same result, I decided to try programming it directly via the isp header. And funny enough, that did work.

So, I can upload through the bootloader just fine, but afterwards it doesn't seem to make to my program code, yet when the same program's loaded through isp, it does work. Is this a case of me not reading enough of the fine manual and overlooking something obvious, or is something else going on?

Best regards,
John

[adafruit]

after you've uploaded via the bootloader, are you resetting the board, power cycling, etc? it could be stuck in the bootloader waiting for more data

[jcrood]

Hi,

I've tried both resetting and re-plugging the board, to no avail. After a regular upload the program still doesn't seem to run. In further attempts to make the board behave properly, I figured the bootloader might have been wonky and re-programmed it, but that didn't help either. The only result of this is getting the efuse stuck on 0xC3 (I tried both boot loaders from http://github.com/adafruit/Atmega32u4-Breakout-Board and http://github.com/adafruit/lufa-lib, where the latter sets the efuse to 0xC3 when you use the provided makefile). Now it won't let me reset this to 0xF3, but luckily the upper bits are not in use and I hope this has no ill effect. I assume this can only be fixed with high-voltage programming now?

[adafruit]

upper bits may be read differently. the board and bootloader have been pretty thoroughly tested and it sounds like it works when you ISP program so not sure what could be happening!