Avr fuse setting help!!!

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arunskumar05

Joined Nov 1, 2011
18
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
 

vrainom

Joined Sep 8, 2011
126
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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