AVR-Chat

I think that there have been several threads on AVR Freaks about the EESave fuse. The consensus seems to be that the fuse has NOT protected the EEPROM when the device is being program through the A.S. IDE. And still does not.

Jim

James Wagner
Oregon Research Electronics
http://www.orelectronics.net <http://www.orelectronics.net/>




> On Mar 20, 2017, at 11:36 AM, 'Steven Hodge' steve@terrafirma.us [AVR-Chat] <AVR-Chat@yahoogroups.com> wrote:
> 
> 
> If you are using the latest Atmel Studio (and maybe before that, I can’t remember) there is also a setting in the Project Properties for saving (or not saving) EEPROM.  I think that over-rides the fuse setting in the sense that if set EEPROM will not be erased regardless of the fuse setting.  At any rate, I find getting all the EEPROM settings properly set is at best confusing and complicated.   Steve
> 
>  
> 
> From: AVR-Chat@yahoogroups.com <mailto:AVR-Chat@yahoogroups.com> [mailto:AVR-Chat@yahoogroups.com <mailto:AVR-Chat@yahoogroups.com>] 
> Sent: Monday, March 20, 2017 9:09 AM
> To: AVR-Chat@yahoogroups.com <mailto:AVR-Chat@yahoogroups.com>
> Subject: RE: [AVR-Chat] ATTiny24a EEPROM troubles
> 
>  
> 
>   
> 
> Looked at the datasheet for the 24 and it has an EESAVE bit in the high fuse, set this and the EEPROM will keep its settings when bulk erased Hope that helps,
> 
> Bryan
> 
> Sent from Mail for Windows 10
> 
> From: BryanW purpenuk@yahoo.co.uk <mailto:purpenuk@yahoo.co.uk> [AVR-Chat]
> Sent: 20 March 2017 16:01
> To: AVR-Chat@yahoogroups.com <mailto:AVR-Chat@yahoogroups.com>
> Subject: RE: [AVR-Chat] ATTiny24a EEPROM troubles
> 
>   
> I’m not sure about the tiny24, but is there an EESAVE fuse, as this will protect the EEPROM data when a bulk erase is issued. Otherwise the only way to preserve the EEPROM is by reading it first and then re-writing it
> 
> Sent from Mail for Windows 10
> 
> From: Richard Purcella repurcella@gmail.com <mailto:repurcella@gmail.com> [AVR-Chat]
> Sent: 20 March 2017 15:16
> To: AVR-Chat@yahoogroups.com <mailto:AVR-Chat@yahoogroups.com>
> Subject: Re: [AVR-Chat] ATTiny24a EEPROM troubles
> 
>   
> There is a bulk erase in the avr studio programming ide. It often runs  every programming cycle.
> 
> On Mar 19, 2017 11:48 PM, "richros@adamswells.com [AVR-Chat] <mailto:richros@adamswells.com%20[AVR-Chat]>" <AVR-Chat@yahoogroups.com <mailto:AVR-Chat@yahoogroups.com>> wrote:
>   
> I'm an old-timer in micro's, started back in the mid-70's and have experience in
> just about every one made up through 2002.  (Started with Intel's 4004 & 8008.)
> Didn't get to do much with the Atmel devices then but made up for it since
> retiring.
> 
> I've used most of the ATTiny and some of the ATMega devices and have used
> the EEPROM in several.  This is the first time I used it on the ATTiny24 and
> I've put in nearly a 40 hour week trying to tame it!
> 
> I've used the programming examples right out of the spec sheet and several
> variations of it but no cigars!  I'm pretty sure that the Write works, I can
> program several bytes and then read the micro's EEProm with the AVR
> Studio 4's HEX file read capability.  I can shut down everything and it's
> still there after a complete power-up.  The problem is that everytime I
> do an EEPROM_Read it erases everything.  I don't see anything in the
> specs about a bulk erase!  
> 
> Is there a problem with the ATTiny24A?  The same sequence works with all
> the other devices.
> 
> Oh, by the way, I'm an assembly language programmer and can run circles
> around any of the C programming kids.
> 
> Any help would be greatly appreciated.
> 
> Rich
> 
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> [Non-text portions of this message have been removed]
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