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Associate
April 29, 2026
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EEPROM UID and Identification page

  • April 29, 2026
  • 1 reply
  • 109 views

I am looking for an EEPROM device that has the UID but also supports the 256-byte identification page.

I was lead to believe that densities less than 1M support either/or, but greaterthan/equal to 1M does support both.

However, from what I can tell from the datasheet(s), the -F version (M24M01E-F) says: "The device offers an additional 256-byte page, called the identification page. This page can be used to store sensitive application parameters, which can later be permanently locked in read-only mode."

But the -F version does not have section 4.5 so it does not have UID.  

datasheet for version -U (M24M01E-U) says "The device also offers an additional 256-byte identification page. This page stores a 128‑bit (16‑byte) unique factory-programmed serial number, locked in read-only mode at factory delivery."

And in section 4.4 says "This is an additional 256-byte page, permanently locked in read-only mode. The user can read it by issuing the read identification page instruction"

Section 4.5 clearly explains UID.

Is there a version that supports storing (and locking) parameters in the 256 identification page AND has the UID? or is it either/or? 

 

Thanks

Best answer by Peter BENSCH

Welcome @JMAX604, to the community!

Correct, it is either/or.

Background: the Identification Page is present in both cases, but:

  • the one in the M24M01E-F it is user-writable and lockable
  • the one in the M24M01E-U it is preprogrammed by ST with the UID and additionally locked.

At present, STMicroelectronics has no EEPROM in its product range to fulfil your request:

  • one page (r/o + locked) with UID
  • an additional page (r/w + lockable) for your customer-specific identification information

Maybe your requirements and the intended goal can be met with other solutions, such as a device from the family STSAFE?

Regards
/Peter

1 reply

Peter BENSCH
Technical Moderator
April 30, 2026

Welcome @JMAX604, to the community!

Correct, it is either/or.

Background: the Identification Page is present in both cases, but:

  • the one in the M24M01E-F it is user-writable and lockable
  • the one in the M24M01E-U it is preprogrammed by ST with the UID and additionally locked.

At present, STMicroelectronics has no EEPROM in its product range to fulfil your request:

  • one page (r/o + locked) with UID
  • an additional page (r/w + lockable) for your customer-specific identification information

Maybe your requirements and the intended goal can be met with other solutions, such as a device from the family STSAFE?

Regards
/Peter

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JMAX604Author
Associate
May 5, 2026

FYI

The main reason I checked datasheets and posted here is because CoPilot gave me an answer that I wanted to confirm. CoPilot told me that 1M/2M devices can support both (UID/user) but datasheet was pretty clear that they do not.

Glad I checked :)

 

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