Atmega 8 fuse setting for 16 Mhz external crystal oscillator

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Hi,

I bricked 3 Atmega8 while setting them to work with an crstal oscillator of 16 Mhz.Are the fuse settings Lfuse = FA and Hfuse = D9 are right for 16Mhz crystal (Atmega8) ?

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Certainly you want hfuse=D9 (the default) and don't want to even consider changing that (because of the danger that RSTDISBL might get screwed!

As for lfuse, the value FA looks OK though to extend the start up period (unless you really need to try for a fast start up) maybe consider also setting CKSEL0 to 1 which makes lfuse=FB

But the 101 for CKSEL3:1 certainly looks right for a high speed crystal - just one question though: These are ATmega8-16 and not ATmega8-8 chips aren't they?

Cliff

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Try using an online AVR fuse calculator. It seems to indicate that Lfuse of 0xFA is for a 'low frequency' crystal.

If it's any help, I've used Lfuse = 0xFF, Hfuse=0xC9 for Mega8's on 16Mhz crystals.

Nigel Batten
www.batsocks.co.uk

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You will want CKOPT programmed for 16mhz. Datasheet, p.27 has more info.

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clawson wrote:

just one question though: These are ATmega8-16 and not ATmega8-8 chips aren't they?

Cliff

These are not the Atmega8L series they are the Atmega 8 Series (Higher voltage and Higher frequency versions)

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curtvm wrote:
You will want CKOPT programmed for 16mhz. Datasheet, p.27 has more info.

Yes I agree CKOPT should be programmed which makes Hfuse = C9

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condemned wrote:
Try using an online AVR fuse calculator. It seems to indicate that Lfuse of 0xFA is for a 'low frequency' crystal.

If it's any help, I've used Lfuse = 0xFF, Hfuse=0xC9 for Mega8's on 16Mhz crystals.

Could you tell me why Lfuse = FF please?

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The correct bits is
Lfuse: FF
Hfuse: C9

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After 6 years it may be a little too late. :wink:

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Old thread, but still relevant (at least for me).  I'm trying to set the fuses for a ATMega168PB at 16MHz.  Do you know if I can use the same fuses as the ATMEga168x series?

I did set a config at while back and it worked, but last night when I tried on another board it failed and now I can't access it anymore.  Would love some pointers before loosing a few more boards.  

 

Thank you very much for your time and insights.

~Stephane

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I used LF=EF and High Fuse = C9. But after this I am unable to communicate with target using eXtreme Burner and USBASP. Any idea how I can restore the communication? I have the crystal mounted and 22pf caps.

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Finally)))Problem was not correct FUSE config on ATmega16. I set LOW Fuse Resister on 0xFF and Termite start to receive correct data) BUT I STRONGLY RECOMMENDED TO READ MANUAL TWICE BEFORE SET FUSES Not correct fuses set may cause microcontroller failed permanently.