Though it is very old topic & i am not getting any solution of my problem after tryingl of all the probable procedure discussed earlier in tutorial section.
Few days back i got stuck up with Locked fuse bit of At mega 2560, and i recovered that with external 1Mhz frequency using Another Attiny2313 with clock out at port D2 and selected Internal Clock and clock/8 option as per tutorial of Mr. Clawson.
I tested my code & Set the fuses as -
Lock Bit - (x3C)
1. Mode - Further programming and verification disabled
2. Application Protection Mode - No lock on SPM and LPM in Application .
3. BootLoader Protection Mode - No lock on SPM and LPM in Boot Loader.
High Fuse (xD0)
Boot Flash section size=4096 words Boot start
Enabled - SPI Enable
Enabled - Preserve EEprom Memory
Enable - Boot Reset Vector.
Low Fuse (FF)
Selected External Xtal Osc 8-16 Mhz
Disabled - CKDIV = 8
Disabled - CKOUT = 0
Extended Fuse (xFD)
Brown-out detection level at VCC=2.7 V;
Now i am unable to erase this chip, I can read the fuse but Unable to erase/write any fuse. During chip erase command executed it is showing -
avrdude -C avrdude.conf -c usbasp -p m2560 -e -q
avrdude: AVR device initialized and ready to accept instructions
avrdude: Device signature = 0x1e9801
avrdude: erasing chip
avrdude: safemode: Fuses OK
avrdude done. Thank you.
i am using USBASP with latest firmware.