[sdiy] a provoking question about time

[Roman Sowa]

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