ATmega48A 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.
CKDIV8 Divide clock by 8 internally 1 · unprogrammed 0 · programmed CKOUT Clock output on PORTB0 1 · unprogrammed 0 · programmed SUT_CKSEL Select Clock Source Ext. Clock; Start-up time PWRDWN/RESET: 6 CK/14 CK + 0 ms Int. RC Osc. 8 MHz; Start-up time PWRDWN/RESET: 6 CK/14 CK + 0 ms Int. RC Osc. 128kHz; Start-up time PWRDWN/RESET: 6 CK/14 CK + 0 ms Ext. Low-Freq. Crystal; Start-up time PWRDWN/RESET: 1K CK/14 CK + 0 ms Ext. Low-Freq. Crystal; Start-up time PWRDWN/RESET: 32K CK/14 CK + 0 ms Ext. Full-swing Crystal; Start-up time PWRDWN/RESET: 258 CK/14 CK + 4.1 ms Ext. Full-swing Crystal; Start-up time PWRDWN/RESET: 1K CK /14 CK + 65 ms Ext. Crystal Osc. 0.4-0.9 MHz; Start-up time PWRDWN/RESET: 258 CK/14 CK + 4.1 ms Ext. Crystal Osc. 0.4-0.9 MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 65 ms Ext. Crystal Osc. 0.9-3.0 MHz; Start-up time PWRDWN/RESET: 258 CK/14 CK + 4.1 ms Ext. Crystal Osc. 0.9-3.0 MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 65 ms Ext. Crystal Osc. 3.0-8.0 MHz; Start-up time PWRDWN/RESET: 258 CK/14 CK + 4.1 ms Ext. Crystal Osc. 3.0-8.0 MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 65 ms Ext. Crystal Osc. 8.0- MHz; Start-up time PWRDWN/RESET: 258 CK/14 CK + 4.1 ms Ext. Crystal Osc. 8.0- MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 65 ms Ext. Clock; Start-up time PWRDWN/RESET: 6 CK/14 CK + 4.1 ms Int. RC Osc. 8 MHz; Start-up time PWRDWN/RESET: 6 CK/14 CK + 4.1 ms Int. RC Osc. 128kHz; Start-up time PWRDWN/RESET: 6 CK/14 CK + 4.1 ms Ext. Low-Freq. Crystal; Start-up time PWRDWN/RESET: 1K CK/14 CK + 4.1 ms Ext. Low-Freq. Crystal; Start-up time PWRDWN/RESET: 32K CK/14 CK + 4.1 ms Ext. Full-swing Crystal; Start-up time PWRDWN/RESET: 258 CK/14 CK + 65 ms Ext. Full-swing Crystal; Start-up time PWRDWN/RESET: 16K CK/14 CK + 0 ms Ext. Crystal Osc. 0.4-0.9 MHz; Start-up time PWRDWN/RESET: 258 CK/14 CK + 65 ms Ext. Crystal Osc. 0.4-0.9 MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 0 ms Ext. Crystal Osc. 0.9-3.0 MHz; Start-up time PWRDWN/RESET: 258 CK/14 CK + 65 ms Ext. Crystal Osc. 0.9-3.0 MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 0 ms Ext. Crystal Osc. 3.0-8.0 MHz; Start-up time PWRDWN/RESET: 258 CK/14 CK + 65 ms Ext. Crystal Osc. 3.0-8.0 MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 0 ms Ext. Crystal Osc. 8.0- MHz; Start-up time PWRDWN/RESET: 258 CK/14 CK + 65 ms Ext. Crystal Osc. 8.0- MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 0 ms Ext. Clock; Start-up time PWRDWN/RESET: 6 CK/14 CK + 65 ms Int. RC Osc. 8 MHz; Start-up time PWRDWN/RESET: 6 CK/14 CK + 65 ms; default value Int. RC Osc. 128kHz; Start-up time PWRDWN/RESET: 6 CK/14 CK + 65 ms Ext. Low-Freq. Crystal; Start-up time PWRDWN/RESET: 1K CK/14 CK + 65 ms Ext. Low-Freq. Crystal; Start-up time PWRDWN/RESET: 32K CK/14 CK + 65 ms Ext. Full-swing Crystal; Start-up time PWRDWN/RESET: 1K CK /14 CK + 0 ms Ext. Full-swing Crystal; Start-up time PWRDWN/RESET: 16K CK/14 CK + 4.1 ms Ext. Crystal Osc. 0.4-0.9 MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 0 ms Ext. Crystal Osc. 0.4-0.9 MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 4.1 ms Ext. Crystal Osc. 0.9-3.0 MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 0 ms Ext. Crystal Osc. 0.9-3.0 MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 4.1 ms Ext. Crystal Osc. 3.0-8.0 MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 0 ms Ext. Crystal Osc. 3.0-8.0 MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 4.1 ms Ext. Crystal Osc. 8.0- MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 0 ms Ext. Crystal Osc. 8.0- MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 4.1 ms Ext. Full-swing Crystal; Start-up time PWRDWN/RESET: 1K CK /14 CK + 4.1 ms Ext. Full-swing Crystal; Start-up time PWRDWN/RESET: 16K CK/14 CK + 65 ms Ext. Crystal Osc. 0.4-0.9 MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 4.1 ms Ext. Crystal Osc. 0.4-0.9 MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 65 ms Ext. Crystal Osc. 0.9-3.0 MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 4.1 ms Ext. Crystal Osc. 0.9-3.0 MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 65 ms Ext. Crystal Osc. 3.0-8.0 MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 4.1 ms Ext. Crystal Osc. 3.0-8.0 MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 65 ms Ext. Crystal Osc. 8.0- MHz; Start-up time PWRDWN/RESET: 1K CK /14 CK + 4.1 ms Ext. Crystal Osc. 8.0- MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 65 ms HIGH fuse 0xDF default 0xDF RSTDISBL Reset Disabled (Enable PC6 as i/o pin) 1 · unprogrammed 0 · programmed DWEN Debug Wire enable 1 · unprogrammed 0 · programmed SPIEN Serial program downloading (SPI) enabled 1 · unprogrammed 0 · programmed WDTON Watch-dog Timer always on 1 · unprogrammed 0 · programmed EESAVE Preserve EEPROM through the Chip Erase cycle 1 · unprogrammed 0 · programmed BODLEVEL Brown-out Detector trigger level Brown-out detection at VCC=4.3 V Brown-out detection at VCC=2.7 V Brown-out detection at VCC=1.8 V Brown-out detection disabled EXTENDED fuse 0xFF default 0xFF SELFPRGEN Self Programming enable 1 · unprogrammed 0 · programmed Lock bits 0xFF default 0xFF LB Memory Lock Further programming and verification disabled Further programming disabled No memory lock features enabled