RE: [AVR-Chat] RE: ATmega88PA EEPROM Memory Life
2012-12-13 by Tim Mitchell
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From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf Of Bob Paddock Sent: 13 December 2012 02:44 To: AVR-Chat@yahoogroups.com Subject: Re: [AVR-Chat] RE: ATmega88PA EEPROM Memory Life > I've always gone conservative and assumed EEPROM wears by > pages. Can > someone point to a definitive Atmel answer? As far as I understand it, and I was told by an Atmel FAE who may or may not have known what they were talking about, Eeprom wears by bits. When you write a bit from 1 (erased) to 0 (programmed) then that's one cycle for that bit. If the bit pattern of the stored number doesn't change the state of that bit, then it isn't a write cycle for that bit. And the magic 100,000 figure is not a real-life tested value, it is just a very pessimistic calculation. A bit like the quoted 50,000 hour life for LEDs. You will always get more than 100,000 writes, but in a critical application you can't rely on it. I have seen results on the web of tests people have done where the endurance on their tested devices is over 10 million writes and counting. -- Tim Mitchell