ATmega8 fuses & lock bits
The fuse bytes set the clock, start-up, brown-out and boot options; the lock bits protect flash and EEPROM. A fuse bit is programmed at 0 . Change a setting and the byte below updates; the starting values are the factory defaults.
BODLEVEL Brownout detector trigger level Brown-out detection at VCC=4.0 V Brown-out detection at VCC=2.7 V BODEN Brown-out detection enabled 1 · unprogrammed 0 · programmed SUT_CKSEL Select Clock Source Ext. Clock; Start-up time: 6 CK + 0 ms Int. RC Osc. 1 MHz; Start-up time: 6 CK + 0 ms Int. RC Osc. 2 MHz; Start-up time: 6 CK + 0 ms Int. RC Osc. 4 MHz; Start-up time: 6 CK + 0 ms Int. RC Osc. 8 MHz; Start-up time: 6 CK + 0 ms Ext. RC Osc. - 0.9 MHz; Start-up time: 18 CK + 0 ms Ext. RC Osc. 0.9 MHz - 3.0 MHz; Start-up time: 18 CK + 0 ms Ext. RC Osc. 3.0 MHz - 8.0 MHz; Start-up time: 18 CK + 0 ms Ext. RC Osc. 8.0 MHz - 12.0 MHz; Start-up time: 18 CK + 0 ms Ext. Low-Freq. Crystal; Start-up time: 1K CK + 4 ms Ext. Crystal/Resonator Low Freq.; Start-up time: 258 CK + 4 ms Ext. Crystal/Resonator Low Freq.; Start-up time: 1K CK + 64 ms Ext. Crystal/Resonator Medium Freq.; Start-up time: 258 CK + 4 ms Ext. Crystal/Resonator Medium Freq.; Start-up time: 1K CK + 64 ms Ext. Crystal/Resonator High Freq.; Start-up time: 258 CK + 4 ms Ext. Crystal/Resonator High Freq.; Start-up time: 1K CK + 64 ms Ext. Clock; Start-up time: 6 CK + 4 ms Int. RC Osc. 1 MHz; Start-up time: 6 CK + 4 ms Int. RC Osc. 2 MHz; Start-up time: 6 CK + 4 ms Int. RC Osc. 4 MHz; Start-up time: 6 CK + 4 ms Int. RC Osc. 8 MHz; Start-up time: 6 CK + 4 ms Ext. RC Osc. - 0.9 MHz; Start-up time: 18 CK + 4 ms Ext. RC Osc. 0.9 MHz - 3.0 MHz; Start-up time: 18 CK + 4 ms Ext. RC Osc. 3.0 MHz - 8.0 MHz; Start-up time: 18 CK + 4 ms Ext. RC Osc. 8.0 MHz - 12.0 MHz; Start-up time: 18 CK + 4 ms Ext. Low-Freq. Crystal; Start-up time: 1K CK + 64 ms Ext. Crystal/Resonator Low Freq.; Start-up time: 258 CK + 64 ms Ext. Crystal/Resonator Low Freq.; Start-up time: 16K CK + 0 ms Ext. Crystal/Resonator Medium Freq.; Start-up time: 258 CK + 64 ms Ext. Crystal/Resonator Medium Freq.; Start-up time: 16K CK + 0 ms Ext. Crystal/Resonator High Freq.; Start-up time: 258 CK + 64 ms Ext. Crystal/Resonator High Freq.; Start-up time: 16K CK + 0 ms Ext. Clock; Start-up time: 6 CK + 64 ms Int. RC Osc. 1 MHz; Start-up time: 6 CK + 64 ms; default value Int. RC Osc. 2 MHz; Start-up time: 6 CK + 64 ms Int. RC Osc. 4 MHz; Start-up time: 6 CK + 64 ms Int. RC Osc. 8 MHz; Start-up time: 6 CK + 64 ms Ext. RC Osc. - 0.9 MHz; Start-up time: 18 CK + 64 ms Ext. RC Osc. 0.9 MHz - 3.0 MHz; Start-up time: 18 CK + 64 ms Ext. RC Osc. 3.0 MHz - 8.0 MHz; Start-up time: 18 CK + 64 ms Ext. RC Osc. 8.0 MHz - 12.0 MHz; Start-up time: 18 CK + 64 ms Ext. Low-Freq. Crystal; Start-up time: 32K CK + 64 ms Ext. Crystal/Resonator Low Freq.; Start-up time: 1K CK + 0 ms Ext. Crystal/Resonator Low Freq.; Start-up time: 16K CK + 4 ms Ext. Crystal/Resonator Medium Freq.; Start-up time: 1K CK + 0 ms Ext. Crystal/Resonator Medium Freq.; Start-up time: 16K CK + 4 ms Ext. Crystal/Resonator High Freq.; Start-up time: 1K CK + 0 ms Ext. Crystal/Resonator High Freq.; Start-up time: 16K CK + 4 ms Ext. RC Osc. - 0.9 MHz; Start-up time: 6 CK + 4 ms Ext. RC Osc. 0.9 MHz - 3.0 MHz; Start-up time: 6 CK + 4 ms Ext. RC Osc. 3.0 MHz - 8.0 MHz; Start-up time: 6 CK + 4 ms Ext. RC Osc. 8.0 MHz - 12.0 MHz; Start-up time: 6 CK + 4 ms Ext. Crystal/Resonator Low Freq.; Start-up time: 1K CK + 4 ms Ext. Crystal/Resonator Low Freq.; Start-up time: 16K CK + 64 ms Ext. Crystal/Resonator Medium Freq.; Start-up time: 1K CK + 4 ms Ext. Crystal/Resonator Medium Freq.; Start-up time: 16K CK + 64 ms Ext. Crystal/Resonator High Freq.; Start-up time: 1K CK + 4 ms Ext. Crystal/Resonator High Freq.; Start-up time: 16K CK + 64 ms HIGH fuse 0xD9 default 0xD9 RSTDISBL Reset Disabled (Enable PC6 as i/o pin) 1 · unprogrammed 0 · programmed WDTON Watch-dog Timer always on 1 · unprogrammed 0 · programmed SPIEN Serial program downloading (SPI) enabled 1 · unprogrammed 0 · programmed CKOPT CKOPT fuse (operation dependent of CKSEL fuses) 1 · unprogrammed 0 · programmed EESAVE Preserve EEPROM through the Chip Erase cycle 1 · unprogrammed 0 · programmed BOOTSZ Select Boot Size Boot Flash size=1024 words Boot address=$0C00 Boot Flash size=512 words Boot address=$0E00 Boot Flash size=256 words Boot address=$0F00 Boot Flash size=128 words Boot address=$0F80 BOOTRST Boot Reset vector Enabled 1 · unprogrammed 0 · programmed Lock bits 0xFF default 0xFF BLB1 Boot Loader Protection Mode LPM and SPM prohibited in Boot Section LPM prohibited in Boot Section SPM prohibited in Boot Section No lock on SPM and LPM in Boot Section BLB0 Boot Loader Protection Mode LPM and SPM prohibited in Application Section LPM prohibited in Application Section SPM prohibited in Application Section No lock on SPM and LPM in Application Section LB Memory Lock Further programming and verification disabled Further programming disabled No memory lock features enabled