Setting AVR fuse bits correctly is most important and equally confusing part for many beginners. In this post I have presented some of the ready to use fuse bit settings and corresponding batch files, which can be used with AVRdude.
Link for downloading avrdude batch files (to be used with USBasp) is given at the end of this post.
Microcontroller |
H fuse |
L fuse |
Description |
ATmega16/32 |
0x99 |
0xE1 |
Factory Default Settings for ATmega16/32. H fuse: JTAG : Enabled OCD : Disabled SPI Programming : Enabled CKOPT : Unprogrammed EEPROM Preserve : Unprogrammed (EEPROM not preserved) BOOT size : 1024 words Reset Vector : User flash code L fuse: Brown-out level : 2.7V Brown-out detect: Disabled Startup timing : Default Clock Source : Internal, 1MHz |
ATmega16/32 |
0xD9 |
0xFF |
External Crystal upto 16MHz, JTAG disabled. Rest of the options : Default. |
ATmega16/32 |
0xD9 |
0xE4 |
Internal 8MHz oscillator, JTAG disabled. Rest of the options : Default. |
ATmega8 |
0xD9 |
0xE1 |
Factory Default Settings for ATmega8. H fuse: Reset Disabled : Unprogrammed (Reset pin is enabled) Watchdog : Off SPI Programming : Enabled CKOPT : Unprogrammed EEPROM Preserve : Unprogrammed (EEPROM not preserved) BOOT size : 1024 words Reset Vector : User flash code L fuse: Brown-out level : 2.7V Brown-out detect: Disabled Startup timing : Default Clock Source : Internal, 1MHz |
ATmega8 |
0xD9 |
0xEF |
External Crystal upto 16MHz. Rest of the options : Default. |
ATtiny13 |
0xFF |
0x6A |
Factory Default Settings for ATtiny13. H fuse: Self programming: Disabled debugWire : Disabled Brown-out detect: Disabled Reset Disabled : Unprogrammed (Reset pin is enabled) L fuse: SPI Programming : Enabled EEPROM Preserve : Unprogrammed (EEPROM not preserved) Watchdog : Off Clock div by 8 : Enabled Startup timing : Default Clock Source : Internal, 9.6MHz |
ATtiny13 |
0xFF |
0x69 |
Internal 4.8MHz oscillator, Divide clock by 8. Rest of the options : Default |
ATtiny13 |
0xFF |
0x79 |
Internal 9.6MHz oscillator, clock is not divided by 8. Rest of the options : Default. |
Fuse programming is most crucial and any mistake might lead to non-functioning AVR controller. I have also made DOS batch files, which can be used to apply above mentioned settings with AVRdude and USBasp. You can download these files from :
AVR Dude – DOS batch files for fuse bit settings using USBasp. [Note: Your antivirus may mark these files as suspicious since they are executable BATCH files. Ignore those warnings or disable antivirus temporarily]