[sdiy] a provoking question about time

Richie Burnett rburnett at richieburnett.co.uk
Sat Jun 25 16:29:40 CEST 2022


It was dsPIC30F series that the company I worked for used in their product. 
dsPIC30F series have 40 year minimum Flash retention and "Typical" of 100 
years on their datasheet if I remember correctly.  I know it is longer than 
the 2nd generation dsPIC33F models with the reduced geometry.  -Richie,




-----Original Message----- 
From: Roman Sowa
Sent: Friday, June 24, 2022 2:25 PM
To: rburnett at richieburnett.co.uk
Cc: Synth-diy
Subject: Re: [sdiy] a provoking question about time

Richie, it was dsPIC30F6011

Roman

W dniu 2022-06-23 o 14:18, rburnett at richieburnett.co.uk pisze:
> Roman are you talking about "bit rot" in the program Flash of dsPICs? Can 
> you remember the part number of the devices that you observed the issue 
> with?
>
> -Richie,
>
>
> On 2022-06-23 13:02, Tom Wiltshire wrote:
>> Could you instead assume some "average number of boot-ups per year"
>> and then re-write the memory at start-up after the chip has booted up
>> X times?
>>
>> For some people who leave the thing in the cupboard for years, it
>> won't help them, but then again, if they pull it out of the cupboard
>> after 15 years and it doesn't work, they're not exactly going to be
>> surprised. For everyone else, it might be enough. For regular users,
>> it might write the memory more than necessary, but it wouldn't be
>> frequently enough to really shorten the lifespan.
>>
>> HTH,
>> Tom
>>
>> ==================
>>        Electric Druid
>> Synth & Stompbox DIY
>> ==================
>>
>>
>>
>>> On 23 Jun 2022, at 10:34, Roman Sowa <modular at go2.pl> wrote:
>>>
>>> Hello,
>>> what are your concerns about flash retention time in microcontrollers? 
>>> Usually PIC18 and PIC16 claim 40 years in datasheet, but dsPIC only 20.
>>> I've seen corrupted memory in products made about 15 years ago with 
>>> dsPIC, so datasheet value seems real.
>>>
>>> One way to do it is to rewrite all memory from time to time, but how to 
>>> do that? Even if there's real time clock running, the user may always 
>>> change the date, and if it's not alowed, the battery or supercapacitor 
>>> may die, or get ripped away. My idea is to clearly state somewhere, in 
>>> manual, or on the device "please run maintenance procedure if it's year 
>>> ending with 0 or 5" but I'm affraid nobody will do that anyway, and it 
>>> seems foolish.
>>>
>>> People have no problem giving their cars every year for expensive 
>>> maintenance, but nearly nobody ever does that with non-industrial 
>>> electronic equipment. That goes sligltly better with musical 
>>> instruments, but anyway many of them go to service only after it's too 
>>> late and it's simply broken.
>>>
>>> I'm not very fond of general trend which is "buy new stuff every 2 
>>> years".
>>>
>>> Roman
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>>
>>
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