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DP83849ID: How to judge link

user4907972
Prodigy 20 points
Part Number: DP83849ID

Dears,

         I used DP83849IDVS with AVAGO optical transceiver module, If I connected the RX of A, and whether I connected the TX of A or B,the LED of the module A will on.Module B is the same as A.occasionally sometimes ,the device with DP83849 run for a period of time to show network barrier ,At this time link and so on may display the error. even, there were no connection on either A or B,the LED would be on too.

         How about this?Why?can you tell me what is  the method of DP83849IDVS judging link.There's my schematic and the test.

(1) The MODA  link  led on

(2)The MODB  link  led on

DP83849IDVS_test.doc

  • 0
    TI__Mastermind 23675 points
    Hi,

    The DP83849IDVS will determine link based off of the received stream from the transceiver or from signal detect pin.
    Are you using signal detect?
    From what you describe above it does not sound like there is an issue.
    Do you mind explaining what you mean about network barrier and displaying an error?

    Thank you,
    Ross
  • 0 in reply to Ross Pimentel
    Prodigy 20 points

    hi Ross,
    Thank you for your reply！The attach is my test ，is it right? network barrier and displaying an error is that the Link connection is correct，but no data transceiver，but the link led is ok, even remove connection. in this case，Turn off the device and turn it on again，It's all right again. How about this?

    thank you !

    DP83849IDVS.doc

  • 0 in reply to user4907972
    TI__Mastermind 23675 points
    Hi,

    What might be happening is the switch also supports Far-End Fault like the DP83849.
    Far-End Fault is a way to determine link failure when not using the Signal Detect pin.
    Do you know if your switch supports this?

    Also, from the document, it looks like the PHYs are operating properly when the correct configuration is used (i.e. TX and RX connected).

    You can disable Far-End Fault detection through firmware with setting:
    Register 0x16h (PCSR) bit[3] = 0.

    Kind regards,
    Ross