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MSP430FR2476: FRAM data when power supply turn off

Ryo Akashi
Genius 9470 points

Part Number: MSP430FR2476

Hello experts,

I have question about FRAM data retention when power supply turn off.
In user's guide 6.3, there is description that "A FRAM read always requires a write back to the same memory location with the same information read.".
If power supply turn off during write back operation, will the FRAM data retained?

Customer write program on FRAM area, so FRAM is always read during program running.
They would like to know whether it is possible to turn off  power supply at any time during program running. 

I would appreciate if you would give me reply.

Thanks and best regards,
Ryo Akashi
  • 0
    TI__Guru 71216 points

    Hi Ryo,

    Yes.  The MSP430's FRAM controller handles the read/write back operation automatically, even through a power down event.  To clarify, the FRAM controller will complete the read/write operation to the currently addressed memory location.  If, however, customer is writing more than one location, say an array of data, then power is removed, obviously not all of the data will be saved.  Is this clear?

  • 0 in reply to Dennis Lehman
    TI__Genius 9470 points

    Hello Dennis-san,

    Thank you for your reply.
    I understand MSP430 FRAM controller's will save the data for addressed memory location.
    Let me confirm my understanding.
    If power-down event occur during read/write operation on location "A" on memory, the data on "A" will be saved even if power-down occur,
    And the data on location before "A" and after "A" will also keep.
    But, if power-down event occur during read/write operation on location "A" on memory when they try to read/write operation on location "A, B, etc...",
    The data on location "A" will be saved but other data (e.g. location B, etc...) will not be saved.
    Is my understanding correct?
    Also, if they want to save all program data on memory, is there any required timing for power-down?
    From user-guide, it is little bit difficult to decide, so I would appreciate if you would give me reply.

    Thanks and best regards,
    Ryo Akashi 
  • 0 in reply to Ryo Akashi
    TI__Genius 9470 points

    Hello Dennis-san,

    Could you give me reply?
    Thank you for your support.

    Thanks and best regards,
    Ryo Akashi
  • 0 in reply to Ryo Akashi
    TI__Guru 71216 points

    Hi Ryo,

    I sincerely apologize for the delay.

    Customer question:

    If power-down event occur during read/write operation on location "A" on memory, the data on "A" will be saved even if power-down occur,
    And the data on location before "A" and after "A" will also keep. - correct.
    But, if power-down event occur during read/write operation on location "A" on memory when they try to read/write operation on location "A, B, etc...",
    The data on location "A" will be saved but other data (e.g. location B, etc...) will not be saved.
    Is my understanding correct? - Yes, correct.
    Also, if they want to save all program data on memory, is there any required timing for power-down? - The FRAM controller has only enough time to complete the current read or write operation for the specific location it is currently addressing.
  • 0 in reply to Dennis Lehman
    TI__Genius 9470 points

    Hello Dennis-san,

    Thank you very much for your reply.
    I understand the details.

    Thanks and best regards,
    Ryo Akashi

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