Skip to main content
Visitor II
May 20, 2019
Question

How to read the data from M95256 EEPROM?

  • May 20, 2019
  • 2 replies
  • 2066 views

I'm using M95256 IC which is used as an external EEPROM for the controller. When i'm sending Read Status Register command i can see data from IC in receive buffer. But when i'm sending Read from Memory command, i get only 0xFF data in the buffer.I have checked the Status register after Write to memory command and the WIP = 0 and WEL=1 in the register. I'm not able to see the data on the oscilloscope as well even though i can see Read from memory command is getting transmitted in Tx Buffer as well as i can see it on oscilloscope.

    This topic has been closed for replies.

    2 replies

    ST Employee
    May 20, 2019

    ​Hello,

    Please follow section 6.5 of datasheet attached.

    Warning: Read operation can't be performed if a Write cycle is currently in progress.

    Moreover, your status register value should be with WIP & WEL=0. I f WEL= 1 it means the write instruction didn't success.

    0xFF correspond to the delivery state.

    BR

    EEPROM suPPort team

    ATUNDAuthor
    Visitor II
    May 20, 2019

    Hi,

    My instructions sequence is:

    1.WRITE ENABLE

    2.WRITE STATUS REGISTER

    3.WRITE DISABLE

    4.READ STATUS REGISTER

    5.WRITE ENABLE

    6.WRITE MEMORY ARRAY

    7.WRITE DISABLE

    8.READ STATUS REGISTER

    9.READ FROM MEMORY ARRAY

    I have added delay of 5ms in between the instructions. But still the value of status register remains same i.e. WIP=0 and WEL=1.

    ATUNDAuthor
    Visitor II
    May 20, 2019

    Hi,

    My instructions sequence is:

    1.WRITE ENABLE

    2.WRITE STATUS REGISTER

    3.WRITE DISABLE

    4.READ STATUS REGISTER

    5.WRITE ENABLE

    6.WRITE MEMORY ARRAY

    7.WRITE DISABLE

    8.READ STATUS REGISTER

    9.READ FROM MEMORY ARRAY

    I have added delay of 5ms in between the instructions. But still the value of status register remains same i.e. WIP=0 and WEL=1.