Avr fuse setting help!!!

Thread Starter


Joined Nov 1, 2011
I am beginner in avr programming..
i am using usbasp programmer and avrdude
in my program i am using the internal oscillator 8 mhz
i had calculated the fuse bit using some online fuse bit calculator..and bricked 2 atmega8 mcu..
what will be the required high and low fuse bit selected for my program..
please help 8mhz internal osc. for atmega8 using avrdude


Joined Sep 8, 2011
Take a look at the datasheet in http://www.atmel.com/images/doc2486.pdf pages 216 and 217 and familiarize with it, read through it to understand how to do what you want and why.

Now here's a short explanation. Note that the bits are active or programed when they're 0 and unactive or unprogrammed when they're 1. So 0 is on and 1 is off.

Fuse high byte is:
bit 7: Reset disable, 1 we want this one off as activating it would disable the reset and thus the serial programming.
bit 6: watch dog timer on, 1 it's off by default.
bit 5: serial programming enable, 0 we want this one on to use the usbasp serial programmer
bit 4: clock options, 1 this one has to do with external crystal oscillators which you won't use, so off
bit 3: eeprom save, 1 by default activate it with a 0 if you want the eeprom data to survive the chip erase command
bit 2: boot size1, 0 by default
bit 1: boot size0, 0 by default
bit 0: boot reset, 1 by default activate it with a 0 if you want to use the boot loader

So that would be Fuse high byte: b11011001 or 0xd9

Fuse low byte:
bit 7: brown out detector level, 1 lower brown out voltage by default
bit 6: brown out enable, 1 off by default
bit 5: start up time1, 1 longest by default
bit 4: start up time0, 0 longest by default
bit 3-0: clock source, 0100 internal oscillator 8mhz as you want

so fuse low byte: b11100100 or 0xe4
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