While I was trying to change the fuse bits of ATmega328P of my Arduino pro mini using a USBasp device to operate it at 3.3 V/8 MHz, it failed due to the bad connection I guess. After that, the USBasp programmer can't detect the chip.

Does the MCU get bricked/locked?

How can I recover this?

Is there any way to solve this problem using an AVR Dragon board? If yes, please let me know the whole process.


Does the MCU get bricked/locked?

Yes, it's possible. The chip requires a valid clock to run, even when programming, so if the clock settings are corrupt or were set wrong it will no longer be programmable through ICSP.

How can I recover this?

Depending on what has actually happened you can either supply an external clock signal to the chip to get it working again, or you may need to reprogram the chip through the parallel programming interface, also known as HVP (High Voltage Programming).

Is there any way to solve this problem using AVR Dragon board?

Yes, the Dragon can do parallel programming. You can read more about how to fix fuses with it here.

  • Thank you very much for your answer. I tried to set fuse bits such that it can run at 8MHz internal clock. Before that, it was running at 16MHz external clock. It the fuse bits are set correctly, it thas the internal clock, otherwise, it would be running on external 16MHz clock. May be for the loose connection while writing the fuse bits, the USBasp programmer writes something different in fuse bits. What do you think? – Muhammad Monir Hossain Jul 3 '18 at 13:19
  • @MuhammadMonirHossain Perfectly possible, yes. Or you may have calculated the fuse bits wrong - it's easy enough to do (I have done it myself before now). – Majenko Jul 3 '18 at 13:20
  • I tried with AVR Dragon. But the signature is read 0xDFDFDF that is not expected. What might be the problem? – Muhammad Monir Hossain Jul 3 '18 at 15:26
  • @MuhammadMonirHossain Are you wiring it up for parallel HV programming? – Majenko Jul 3 '18 at 15:44
  • yes, parallel HV programming according to this Go to Device Connection Sheet from this link: microchip.com/webdoc/GUID-04E3421E-81C3-4E6C-BD29-9E1A7BAEBA7E/… – Muhammad Monir Hossain Jul 3 '18 at 16:57

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