11.0592 MHz and 2.7 V BOD

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Speed grades of ATmega644pa (Section 28.2 in full datasheet) says safe operating Vcc for 11.0592 MHz operation is close to 3.0 V.

 

My Vcc is 3V3, so the best BOD setting is 2.7 V which technically isn't sufficient for 10+ MHz operation. What's your take on this?

 

Cheers,
Vignesh

If everything seems to be coming onto your way, then you are probably driving on a wrong lane..

Last Edited: Tue. Mar 3, 2015 - 10:45 AM
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I reckon that you are being a little pedantic.

 

Yes,   if the BOD was absolutely 100% accurate and the AVR was exactly at the lowest in spec.

Then 10MHz would be your 'safest' speed.

 

In practice,   the BOD is a safety measure.   You are designing for a stable 3.3V power supply.    11.059MHz is fine for 3.3V

 

If you are designing for a battery powered app,   you choose the minimum voltage that the battery can fall to.    You will prompt for new battery well before a BOD would kick in.

 

You might choose a voltage boost chip that harvests the last drop of power from your battery to maintain a stable 3.3V.    And then fails catastrophically.

Or you simply warn the punter that the battery is getting low.

 

Only you know what is suitable for your project.

 

David.

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Thank you David.

Cheers,
Vignesh

If everything seems to be coming onto your way, then you are probably driving on a wrong lane..