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Hot!I2C - EEPROM memory area problem ( soft or hard ? )

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jym92
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2019/09/18 00:18:51 (permalink)
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I2C - EEPROM memory area problem ( soft or hard ? )

Hi everyone,
 
 
We are actually using a microcontroler dsPIC33F to communicate with a Microchip 24LC32 or 24AA64 EEPROM module by I2C bus.
 
We’ve noticed specific memory place get their values modified because some bits change from 0 to 1 whatever the previous recorded value. The area which gets faulty values is usually the range 0X00-0X19 of the 0X01 page.
We are using a switch power module supply for the 24V and 5V, and a regulator for the 3V3.
 
Do you think the problem can come from the soft ( I2C communication problem) or from the power supply ?
Have you even had this problem ?
 
 
Thank you in advance for your reply,
 
Regards
#1

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    ric
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    Re: I2C - EEPROM memory area problem ( soft or hard ? ) 2019/09/18 16:08:38 (permalink)
    4 (1)
    Make sure your power supply is stable BEFORE doing any reads of the EEPROM.
    Simply a delay of 100ms or so in your startup may be sufficient to ensure this.
     
    You mention three power supplies, but don't say if the PIC and EEPROM are on the same supply, or what the arrangement is.
     

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    #2
    jym92
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    Re: I2C - EEPROM memory area problem ( soft or hard ? ) 2019/09/19 06:29:19 (permalink)
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    Thanks for your reply !
     
     
    We use the same 3V3 supply for the PIC and EEPROM, and we check the supply stability which is correct in our lab...
     
    But we can't confirm that everywhere we use our system. We work to increase our supply stability to be sure is not an hard problem.
     
    We already set an delay of 100ms after each writting.
     
     
    Do you have already note some problem in range 0X00-0X19 of the 0X01 page ?
    #3
    ric
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    Re: I2C - EEPROM memory area problem ( soft or hard ? ) 2019/09/19 13:18:33 (permalink)
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    jym92
    We use the same 3V3 supply for the PIC and EEPROM, and we check the supply stability which is correct in our lab...

    What did you check?
    I am particularly referring to what happens in the first tens of milliseconds after turn on, not many seconds later.
     

    We already set an delay of 100ms after each writting.

    That's got nothing to do with what happens before and during writing.

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    #4
    jym92
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    Re: I2C - EEPROM memory area problem ( soft or hard ? ) 2019/09/23 01:11:45 (permalink)
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    We checked the supply stability before and after regulator.
     
    Everything look good(no overvoltage), we tried to disturb the supply with motor noise or quick resets but the supply capacitor work well and we don't see any disturb...
     
    Do you think a supply problem can just appear after a reset or a turn on ?
     
    A startup delay was already set after I2C and EEPROM initialisation.
    #5
    Nikolay_Po
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    Re: I2C - EEPROM memory area problem ( soft or hard ? ) 2019/09/23 01:47:37 (permalink)
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    jym92
    A startup delay was already set after I2C and EEPROM initialisation.



    Why before? Try to wait a delay at startup BEFORE EEPROM initialization.
    #6
    ric
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    Re: I2C - EEPROM memory area problem ( soft or hard ? ) 2019/09/23 02:23:42 (permalink)
    4 (1)
    jym92
    We checked the supply stability before and after regulator.
     
    Everything look good(no overvoltage), we tried to disturb the supply with motor noise or quick resets but the supply capacitor work well and we don't see any disturb...

    Again, NOTHING to do with what happens as the power comes on.
     

    Do you think a supply problem can just appear after a reset or a turn on ?

    I'm querying how quickly your supply rises, and if it does just rise, or if there are any dips as it increases from zero to full voltage.
     

    A startup delay was already set after I2C and EEPROM initialisation.

    You keep doing things backwards. AFTER initialisation is too late.

    I also post at: PicForum
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    NEW USERS: Posting images, links and code - workaround for restrictions.
    To get a useful answer, always state which PIC you are using!
    #7
    jym92
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    Re: I2C - EEPROM memory area problem ( soft or hard ? ) 2019/09/23 05:12:19 (permalink)
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    Thanks for your answer...
     
    I will check the supply rise with an oscilloscope.
     
    Normally I have a delay before EEPROM initialization but I will check this too !
     
    I keep you in touch ! 
    #8
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