[sdiy] Rotary Switch -> illuminated PB w/ multicolor LED?

Mike Bryant mbryant at futurehorizons.com
Wed Feb 16 23:01:10 CET 2022

You need to just do writes to bytes in sequence.  So an all 0's (if it's a clear to 1 memory) represents a null location so move onto the next byte for the real data.  Only once you run out of bytes do you need to do a page erase.

-----Original Message-----
From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of grant musictechnologiesgroup.com
Sent: 16 February 2022 21:43
To: sleepy_dog at gmx.de; synth-diy at synth-diy.org
Subject: Re: [sdiy] Rotary Switch -> illuminated PB w/ multicolor LED?

Well in this application I'm only concerned with a few bits total, but I wonder one thing about wear leveling: since changing a single byte means erasing a whole page (bank/block whatever you want to call it), don't you need to implement multiple pages (banks/blocks) to see a benefit?  
Or, where is the weakness? Writing or erasing?

It's kind of funny now seeing this issue pop up for synths. Back in the old days, that battery backed RAM was much more convenient!


------ Original Message ------
From: "Steve via Synth-diy" <synth-diy at synth-diy.org>
To: "synth-diy at synth-diy.org" <synth-diy at synth-diy.org>
Sent: 2/16/2022 12:39:07 PM
Subject: Re: [sdiy] Rotary Switch -> illuminated PB w/ multicolor LED?

>Flash wear:
>One can heavily mitigate the problem by implementing a wear leveling 
>algorithm, though.
>Depending on the concrete hardware & application requirements, one 
>might get away with a pretty simple scheme. I've done that in the past 
>and it worked very well.
>If you only have very limited flash size, it's of not much help, but if 
>you have, say, 10x the amount you need to save, you can reduce the wear 
>of the flash to 1/10, by spreading it out perfectly evenly.
>Jay Schwichtenberg via Synth-diy:
>>  Yes you have to pay attention to the number of writes to flash. I 
>> did  embedded/bare metal work before I retired and there were 2 times 
>> I  wore out the program flash in uCs. These were NXP chips and they 
>> were  probably programmed 10-20 times over 9-12 months.
>>  Jay S.
>>  On 2/15/2022 10:10 PM, Brian Willoughby wrote:
>>>  The replies about EEPROM versus Flash are correct. An EEPROM will  
>>> last through 10 times as many writes as a Flash device. Some of the  
>>> high capacity devices are actually 1/100 of an EEPROM's duration, 
>>> but  I doubt anyone is putting 16GB of NV memory in a module. The 
>>> only  downside is thet EEPROM memory sizes are much smaller, but 
>>> that won't  affect storage of a 2-bit or 3-bit setting. Many PIC and 
>>> other micro  controllers have both Flash and EEPROM for code and 
>>> settings,  respectively.
>>>  Brian
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