Often writing to flash

Ladislav Machan1

Hi I have question how you solve often writing to flash. I'd like to realize a counter that will be persist over power cycles. The problem is physical limit on writing cycles to flash it could about 100,000 and often just with "page erase". Could anybody to recommend me a regular technique or method how to perform persist counter? Thanks

over 12 years ago

0 old_cow_yellow over 12 years ago

Guru 58965 points

Consider on chip FRAM.

0 Ladislav Machan1 over 12 years ago in reply to old_cow_yellow

Prodigy 110 points

I know about FRAM, but we use CC430 and there is no FRAM. Btw FRAM is quite "new" and it seems to me the another way has to exist for older devices (may be software technique). Anyway thank you for replay.

0 Ilmars over 12 years ago in reply to Ladislav Machan1

Guru 46710 points

Ladislav Machan1 said:
I know about FRAM, but we use CC430 and there is no FRAM.

Don't try to write in same flash memory location, instead add new/updated counter values to array. To find latest counter value after restart your application have to search for last entry of the array.

Example: single 31bit counter which counts from 0 to 0x7FFFFFFF. MSB value "0" indicates occupied entry, that's why counter is not 32 bits. In case of two code flash sectors you have 1KB meaning array of 256 entries. So using 1KB to store 31 bit counter you will increase counter storage endurance 256 times comparing to single memory location. You can scale-up or down this approach as needed.

0 Ladislav Machan1 over 12 years ago in reply to Ilmars

Prodigy 110 points

Thank you for advice, this one is what I looked for.

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Often writing to flash