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What is the MC24C08 maximum write cycle count for a given bit or for a given byte? It doesn't say so on the datasheet, and I get conflicting answers when I look up this question for other EEPROMs (made by different manufacturers).

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  • \$\begingroup\$ Which specific STM32 model you mean? Generally they don't even have EEPROM. \$\endgroup\$
    – Justme
    May 12 at 17:06
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    \$\begingroup\$ @Hearth: It also says right on page 1 of the datasheet.... but you're correct that page 23 shows details, including the voltage and temperature conditions under which the front-page performance claim is made. \$\endgroup\$
    – Ben Voigt
    May 12 at 20:29
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    \$\begingroup\$ Given that the front page of the datasheet makes a claim of the number of cycles, but your question mentions "for a bit" and "for a byte", I assume you are asking a more complex question, perhaps similar to the one here (only for a different EEPROM): EEPROM endurance and page size \$\endgroup\$
    – Ben Voigt
    May 12 at 20:39
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    \$\begingroup\$ and also electronics.stackexchange.com/q/262004/1743 \$\endgroup\$
    – Ben Voigt
    May 12 at 20:41
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    \$\begingroup\$ I'm assuming you're using MC24C08 from st.com -- they have an applications note AN4653 about this topic, with graphs and their testing methodology. This kind of QA/appnote document isn't as easy to find as datasheets, but all reputable manufacturers have this kind of information published somewhere on their website. I had to go up to st.com/en/memories/standard-serial-eeprom.html#documentation to find this one. \$\endgroup\$
    – MarkU
    May 13 at 0:45

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As indicated in the application note linked by @MarkU, the write cycle endurance specified in the STM32 datasheet is per byte, not per bit.

EDIT: The application note in question is AN4653, which was linked to STM32's EEPROM MC24C08.

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  • \$\begingroup\$ It was never going to be per bit, but whether it was per byte or per page was a reasonable question. \$\endgroup\$
    – Ben Voigt
    May 13 at 15:47
  • \$\begingroup\$ Also, please write your answer so that it is able to stand alone if all the comments are removed later. It's good to refer to a comment in order to give credit to another user, but referring to it for the essential technical information is not correct; put the application note number, title, and link in your answer. \$\endgroup\$
    – Ben Voigt
    May 13 at 15:50
  • \$\begingroup\$ Hard to believe it would be per byte. At least other chip datasheets say page writes are possible, and memory is internally organized in pages of multiple bytes, and endurance is identical for Byte and Page writes. Microchip 24C08B datasheet says bytes are temporarily stored in a page buffer. I'd say it's more likely to be per page, which is why writes should be made in pages instead of single contiguous bytes. \$\endgroup\$
    – Justme
    May 13 at 17:19
  • \$\begingroup\$ I know that this EEPROM supports both byte write and page write. \$\endgroup\$
    – Dan
    May 13 at 19:40
  • \$\begingroup\$ Yes but even if you write a single byte the chip still needs to do a page write for all writes. \$\endgroup\$
    – Justme
    May 13 at 21:01

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