AVR fuse reset (tested)
When I started to learn microcontroller, i have locked few AVR chips. These chips are very expensive here and hard to found. So I started researching why it occurred. I have found two main reasons why microcontrollers are not responding:
1. wrong clock speed selected
2. Lock bit burned (SPIEN)
I have found a solution to reset fuse bits. here is the schematic.
You can reset Atmega8, Atmega48, Atmega88, Atmega128 by it.
Download the hex and burn it to a Atmega8.
|IC1 (ATmega8)||IC2 (ATmega8/ATmega48/ATmega88/ATmega168)|
No external xtal required. In the schematic the two AVRs are connected directly. You can add 1Kohm resistor to every line to provide some protection for the ATmega8 against inserting the target AVR incorrectly.