Does a (embedded) flash page gets fully erased every write operation?

robert.kanzur · ‎2019-07-31

Good evening,

since NAND flash can be addressed pagewise only (I guess STM32 flash is NAND) and I am able to write for e.g. a single byte to the page, will the whole page gets erased during every write operation?

My presumption is that the page gets buffered somewhere, gets fully erased and the buffer containing the new data will be written back to it. But this would mean that the flash wear would be extremly high.

Would be great if someone has an answer and a reference to some kind of document. I couldn't find any.

Thanks alot!

Uwe Bonnes · ‎2019-07-31

No, flash write does not erase. You must activly erase the page or the sector before or write a pattern that only programs more bits from the erased state to teh programmed state.

PatrickF · ‎2019-07-31

Btw internal Flash embedded in MCUs are 'kindof' NOR-Flash.

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robert.kanzur · ‎2019-07-31

Thanks alot for the fast replies!