Olin Lathrop wrote:
> David Duffy (AVD) wrote:
>   
>> The main reason the EE was used was to persist the unit's status if it
>> was power cycled,
>>     
>
> How about keep the live value in RAM and write it to EEPROM only on power
> down?  It only takes a few milliseconds to write to the EEPROM.  You need to
> detect input power going away, and have a large enough cap on Vdd to keep it
> running for the few ms it takes to detect the power gone signal and save the
> live values in EEPROM.
>   

I had considered that, but the hardware is already deployed so no chance 
to mod the circuit. A replacement chip is possible, but that's the limit 
on what can be done in the field. Also, there are no spare pins 
available for the detection.
David...

-- 
___________________________________________
David Duffy        Audio Visual Devices P/L
Unit 8, 10 Hook St, Capalaba 4157 Australia
Ph: +61 7 38235717      Fax: +61 7 38234717
Our Web Site: www.audiovisualdevices.com.au
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