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DRV8847: Multi DRV8847S operation

Will Wang47
Expert 6910 points
Part Number: DRV8847

Hi Team,

Customer have question about how to operate with muli DRV8847S.

Our datasheet mention that at the beginning, we should disable the nFAULT output by writing the DISFLT bit to 1b, question is how could we write the DRV8847S since all parts have  the same I2C address at the beginning? Could you help explain this?

Best Regards,

Will

  • 0
    TI__Expert 8985 points

    Hi Will,

    To answer the question: The default device address of the DRV8847 device is 0x60 (7-bit address). Therefore, any DRV8847S device can be accessed using this address.

    So, you would write 0x60 where the 7-bit slave address is located in the I2C transaction. 

    Since you will have only one communication line for all devices, all nFAULT outputs will be disabled at the same time.

    After that step, you can manipulate devices independently by pulling the nFAULT pins of the other devices to not be communicated to in a transaction to low to release the I 2C buses of those slave devices. Now only 1 device is connected to master.

    If you still have questions, let me know.

  • 0 in reply to Hector Hernandez Luque
    TI__Expert 6910 points

    Hi Hector,

    Thanks for helping on this.

    For you answer, 'all nFAULT outputs will be disabled at the same time' what would happen if there are some parts that doesn't produce ACK of the I2C instruction? How could guarantee all parts modify the register successfully?

    Thanks and Best Regards,

    Will

  • 0 in reply to Will Wang47
    TI__Expert 8985 points

    Hi Will,

    In this case, in the step when the nfault pins become inputs you can set them to low. if they get set to low through your MCU commands, then you know the write was successful since you can manipulate the nfaults as inputs instead of them being outputs.