Atmega fusebit doctor, as name says it, device for repairing dead Atmega and Attiny family AVRs by writing fabric fusebits. Most common mistakes or problems are a wrong clock source (CKSEL fusebits), disabled SPI programming (SPIEN fuse) or disabled reset pin (RSTDISBL fuse). This simple and cheap circuit will fix you uC in a fraction of a second.
If in first case we can help ourself with clock generator, then in 2nd and 3rd cases bring uC back to life is impossible with standard serial programmer. Most of people do not decide to build parallel programmer because its inconvenient and its cheaper and faster to buy new uC.
This circuit use the high-voltage parallel and serial programming method. Atmega8(doctor) has saved in it’s memory signatures of 96 (so far) AVR Atmega and Attiny uC’s, just put your dead avr in socket, press the START button, and enjoy your good-as-new processor.
There are three slots on board, for most common AVR’s, pins compatible with: DIP28 Atmega8, DIP20 Attiny2313, and DIP40 Atmega32 compatible processors.
There is also an extra goldpin connector with all signals so you can attach adapters:
-the "#1 HVPP adapter" with DIP20-B Attiny26 and DIP40-B Atmega8515 compatible
-the "HVSP adapter" for tiny DIP8 Attiny13 and DIP14 Attiny24 compatible.
-your own adapters for other types of processors, in trough-hole or surface-mounted, you can use the breadboard for this – just connect signals to correct pins. How? Check your AVR datasheet, go to “memory programming” and then “parallel programming” – check the signal names, all signals are described under the DIP40 slot.