AVR-Chat

On Apr 27, 2008, at 9:24 PM, Don Kinzer wrote:

> --- In AVR-Chat@yahoogroups.com, David Kelly <dkelly@...> wrote:
>> On AVR one doesn't have that control, the entire byte is
>> erased as part of the write.
>>
> On some new AVRs (e.g. ATmega644) you can separate the erase and write
> process.  This allows you to code your EEPROM writing routine to erase
> if the value is being set to 0xff, perform only the write function if
> the bits that are changing are being cleared, or perform both the
> erase and write.  The advantage of this tactic is that the operations
> take varying amounts of time.

Every few years I wonder about how to make an odometer in EEPROM with  
evenly distributed writes over the EEPROM bits.

The best I have come up with is a pool of bits to use as a tally for  
each increment. March through the array toggling bits. Then have an  
old fashioned traditional counter for the number of times one has been  
completely through the bit pool. Need a counting system where the LSB  
doesn't toggle every time.

--
David Kelly N4HHE, dkelly@HiWAAY.net
========================================================================
Whom computers would destroy, they must first drive mad.