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LPC804 FLASH write disturbance

Question asked by Johan Forslöf on Feb 12, 2020
Latest reply on Feb 20, 2020 by Johan Forslöf

I would like to have the requirements for avoiding FLASH write disturbance when erasing single pages clarified. The user manual (UM11065, rev 1.3) includes the following statement under section 4.5.7, page 26:

To avoid write disturbance (a mechanism intrinsic to flash memories), an erase
should be performed after 16 consecutive writes inside the same page. Note that the
erase operation then erases the entire sector.
Remark: Once a page has been written to 16 times, it is still possible to write to other
pages within the same sector without performing a sector erase (assuming that those
pages have been erased previously).

Will erasing 64-byte pages using the IAP erase pages command (section 4.6.10) instead of erasing complete 1024-byte sectors using the erase sectors command (section 4.6.3) cause write disturbance?

 

My goal is to use the internal FLASH for EEPROM emulation. I cannot afford to use a complete 1024 byte sector and would like to repeatedly erase rewrite a single 64-byte page. Will this use case causes write disturbance and if so can it be mitigated by reserving the adjacent pages as no-go zones?

 

Thank you in advance for your assistance.

 

Regards,

Johan

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