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M
MAhme.4
Visitor II
October 18, 2020
Question

M24M02-A125 Page Write problem, No Erase functionality, No memory organization details

  • October 18, 2020
  • 1 reply
  • 1216 views

We are working on an IOT product for last 3 years. We were using other manufacturers EEPROM but then last year we switched to M24M02-A125, because of I2C interface and 4 million endurance cycle.

But we are facing two problems with this EEPROM.

1 - There is no option for entire chip erase.

That's why i have to perform individual byte write, which takes too much time and is not good option for long run.

2 - Page Write do not work on 3 out of 4 blocks of memory.

In datasheet it is mentioned that this eeprom can be accessed by 4 different i2c address, which divides the memory in 4 block. For byte write, it is working fine, but for Page write, only 1st blocks works but that also skips the data at address with 0x01 0x00. (Lower Byte, Upper Byte).

Why it is happening, there is no mention in the data sheet, what is the memory architecture inside this eeprom. How cells are arranged?

Can you please more detailed documentation for this eeprom also is there any driver file available?

Thanks alot

Waiting for your response.

    This topic has been closed for replies.

    1 reply

    P
    Pierre P.
    ST Employee
    October 19, 2020

    Hello,

    There is no entire chip erase command on our eeprom memories. The erase is managed internally during the write operation.

    Whatever the byte value, you can update it with a simple write command and new byte value.

    For the" page write do not work", the device select code embeds the A16 & A17 MSB bit of the address and the E2 bit of chip enable address. So only 2 addressing possibilities. I don't really catch your sentence " which divides the memory in 4 block". Let me know.( if necessary we will continue the support by email).

    BR

    Team EEPROM suPPort

    M
    MAhme.4Author
    Visitor II
    October 19, 2020
    ​Ok in understand that there is no chip erase command.
    For that i have to write each byte to 0xFF for erase. And i want to do a page write, rather than a byte write.
    But the problem is that Page write is not working on all memories of flash.
    Let me explain, A16 and A17 has 4 combinations.
    00
    01
    10
    11
    And individual byte write is working fine. But page write only works when A16 and A17 is 00 ,, other combinations dont work on page write. How ever byte write is working fine.
    That is why i want to know the internal memory organization.
    Datasheets says
    It has a page size of 256 Bytes and total memory is 256K Bytes
    Which means flash has 1k pages.
    How theses pages are organized in the memory?
    Any documentation, diagram etc will help..
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