Currently I'm working on a project using an ATmega 2560 microcontroller card with a 10 MHz crystal. My main goal is to use the Arduino IDE to upload sketches to this chip to run my bread board circuit. In the beginning I had planned to use Atmel Studio to upload Arduino Sketches, but I decided to go with the more direct route. I am using two programmers, the Atmel ICE, and the Atmel AVR ISP MKii.

Anyway, here is my issue. I tried to use the Arduino IDE and the MKii to burn the bootloader to the chip. However, it did not work. It uploaded, but I was at that point no longer able to communicate with the device. When I switched to Atmel Studio, and used the ICE programmer, my chip could not be read and recognized (whereas before it could). I can't even program it. (I had bought two.)

I then figured I would try and read the fuse bits on the other programmer and burn the bootloader using Atmel Studio (since the Arduino IDE has no information on this), and I looked up the proper bits to change and then burned the bootloader. It worked fine, and I then changed the fuse bits which resulted in an error and now I again could talk to the device.

I am guessing that something is going wrong with the suggested fuse bits, but I do not know how to change them or how to fix this. The original fuse bits that I read from the device are listed below (before I messed it up).

I checked my wiring a billion times and it is all perfect. I just need suggestions to fix this mess, thanks.

OCDEN = [ ]
WDTON = [ ]
EESAVE = [ ]
BOOTSZ = 4096W_1F000
CKDIV8 = [ ]
CKOUT = [ ]
EXTENDED = 0xFF (valid)
HIGH = 0x98 (valid)
LOW = 0xC2 (valid)

LOCKBIT = 0xFF (valid)

Detected device
Device name       ATmega2560
Device signature  0x1E9801
  • Make sure the crystal is connected and the proper capacitors are connected to it.
    – Gerben
    Nov 20, 2014 at 16:58
  • You can check your fuse bit setting here engbedded.com/fusecalc it will tell you what your current fuse bit setting is doing. and if you are really messed up with the fuse bit that you can not even talk to the controller now then the high voltage programming method is a way to fix this and set new fuse bits.
    – Dharmik
    Mar 16, 2021 at 18:56

1 Answer 1


If AVR is bricked because of wrong fuses I suppose it's typically non-working external oscillator you need provide signal to particular AVR pin to get programmer working again. Thread related to unbricking http://www.avrfreaks.net/forum/locked-out-atmega-328p-possible-clocklow-fuse-byte-issue.

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