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MCT8316AEVM: Why writing read only register?

Kenji
Intellectual 530 points
Part Number: MCT8316AEVM
Other Parts Discussed in Thread: MCT8316A

Hi Team

I'm writing I2C communication code to read and write MCT8316 EEPROM.
And I have a few question.

  1. I watched the MCT8316A GUI tool protocol, and it was sending write command to read only register.
    The following is an example with ALGO_STATUS1 Register ( 0xE4).


    Also, I will attach the logic analyzer data when restore to recommended default value.
    You can see the data with Saleae Logic 2 software.
    mct8316_default.zip
  2. There is no explanation anywhere, but when the power is turned on, is the value in the EEPROM automatically transferred to the shadow register?
  3. Is it okay to think that it is controlled by the value held in the shadow register during motor control?
  4. How to know the value to write to EEPROM_WRITE_ACCESS_KEY?
  • 0
    TI__Mastermind 26046 points

    Hi Kenji,

    We'll get you a reply soon.

    Thanks,
    Aaron

  • +1
    TI__Expert 7685 points

    Hi Kenji,

    1. This seems to be a bug in the GUI, which attempts to write to all register addresses. This is unnecessary, but doesn't negatively impact the device algorithm/operation.
    2. Yes, when the device powers up, the EEPROM values are copied into the shadow registers.
    3. Yes, the shadow registers contain values that are actually used by the internal algorithm.
    4. The EEPROM_WRITE_ACCESS_KEY is 0x0 on the preview devices. 

    Regards,
    Eric C.