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DP83TC812S-Q1: Fail Safe Disable Strategy

David Shumate
Expert 7785 points
Part Number: DP83TC812S-Q1

Hi Team,

My customer is trying to find a way to disable the 812 output  in the event of a functional safety fault on ECU or micro SW.

We first looked at the INT pin, but If Micro SW can not be trusted (i.e out of control micro or faulty logic), the concern was that the micro can’t be trusted to configure this pin as an input (via register 0x0011) for safety disabling of Ethernet.

Can the RESET_N pin held low be used as a hardware disable of the Ethernet PHY to guarantee disabling of Ethernet transmissions in case of a functional safety event?

- Is there any other hardware strategy that we could use to disable the Ethernet in the case where micro SW can't be trusted for configuration?

Thanks for the help!

David

  • 0
    TI__Mastermind 26632 points

    Hi David, 

    Yes, holding the RESET_N pin low can be used as a hardware disable of the PHY. Alternately, you can remove power entirely from the device. In either case, please note you will have to reconfigure the registers after releasing the reset pin or restoring power to the device. 

    Thanks,

    David Creger