Saturday, December 28, 2013

AVR Unexpected Signature 0x000102

After spinning my wheels way to long and doing countless “bing” searches, I wound up empty on why when I attempt to program my AVR chip I was getting an Unexpected Signature of 0x000102.  This happened on an initial board I created, and didn’t know if it was a problem with the chip or something else.  Once it happened on a second board with the exact same invalid signature, I knew there had to be a common problem.

If you found this via a search, well you know what I’m talking about…if not, you probably don’t care.


I finally tracked this down to a short between the reset line on my processor (underneath a SMD device) and ground.  Cleaning up the board and life is good.

Hope this saves someone a little bit of time



  1. Thanks for posting this, saved me some time and a lot of frustration! I had two boards that gave me this unrecognized signature error, and after touching up the solder joints to the micros, avrdude correctly recognized the micros.

  2. I set a 10uF and 0.1uF capacitor to the RESET line,every time when I debug with AVRStudio,it happened,but I choose" tool -> decice programming" menu, it is able to read the device ID and Voltage.
    After reading your post,I removed the 10uF capacitor and it works well!

    1. by the way,my debug tool is ATMEL-ICE,MCU is ATMEGA328P.

  3. Wow that was exactly my situation

  4. Thanks for the tip!
    My board was designed for JTAG which I disabled but then decided I needed to try a different bootloader. Anyway, I had the same error code however it wasn't the reset pin for me -- I ended up unsoldering all the SPI pins and lifting them off the pads before mine would program via SPI. It would read without issue just wouldn't program.

    1. ...Yeah, I soldered tiny wires to each of the SPI pins after they were lifted off the pads. I immediately re-enabled the JTAG fuse when I was able to program via SPI.