I am trying to upload some code to the ATmega328 on Sparkfun's 9DOF Razor IMU. Because I don't have an FTDI board at hand I was trying to use my UNO by "grounding" the RESET pin. Communicating with the 9DOF works well (it has some sample firmware loaded):

So here's the problem:

When I try to program the ATmega328, the Arduino IDE gives e the following error:

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x0d

What am I doing wrong?


What you're missing is the signal that resets the ATMega so it can enter the bootloader. That signal is the one that goes to the DTR pin of the 9DOF and would normally be sent to the reset pin on your Arduino (that you are grounding).

What you need to do is reset the 9DOF just as it's about to start trying to upload the code. Timing is critical - you get about a second or so of leeway where the bootloader is actually available for avrdude to talk to.

Alternatively you can try and find a point on your Arduino board where the DTR signal from the USB interface chip is available before it passes through the capacitor to the RESET pin of the Arduino and take a wire from there (wherever that may be) to the DTR pin of the 9DOF.

  • Perfect, thank you for the quick answer! I won't get around to trying anything, but I'll verify it as soon as I can! Thanks again! – Dario Nov 6 '15 at 13:56
  • I simply removed the ATMega and connected RESET and DTR, works well! Thanks again! – Dario Nov 9 '15 at 8:52

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