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DP83TC811S-Q1: diagnostic function

Part Number: DP83TC811S-Q1

Dear team,

I want to know whether DP83TC811S-Q1 supports the following four diagnostic functions.

1. Ethernet cable disconnect

2. Ethernet pin short to each other

3. Ethernet pin short to power

4. Ethernet pin short to GND

1) About the question 1, below is two register: SQI and LSR, which one means Ethernet cable disconnect?

2)About the short diagnostic, I just found below information on the datasheet which only can detect short fault. Can this IC detect short fault type(pin short to each other, short to power, short to GND)? If this IC has this function, could you please tell me which register show these faults?

Thanks & Best Regards,

Sherry

  • Hi Sherry,

    For cable disconnect, you can use the no link indication. There is also a link status bit in register 0x01. Please note that there can be cases where link is down even with cable connected. So cable disconnect is only applicable when link changes from Link up to Link Down.

    For cable short, TDR will only detect the short but there is not indication bits to show the type of shorts.

    -Regards
    Aniruddha
  • Hi Aniruddha,

    Do we have any methods to distinguish below three short faults?

    1. Ethernet pin short to each other

    2. Ethernet pin short to power

    3. Ethernet pin short to GND

    Thanks & Best Regards,
    Sherry
  • Hi Sherry,

    I am not aware of any PHY having the ability to detect pin short to power vs GND.

    Automotive Ethernet is an isolated interface. A single pin short will not kill the link and actually does not even degrade the channel performance.

    You would still be able to maintain link and have data communication if the isolated side has a ground or supply short. This is why the device can work in a PoDL application (Power over data line). If both lines are shorted to ground or power then we can detect this fault and link is lost.