• State Resolved
  • Locked Locked
  • Replies 10 replies
  • Subscribers 101 subscribers
  • Views 1023 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

AM3357: EtherCAT PHY connection issue

Kanae
Mastermind 9815 points
Part Number: AM3357
Other Parts Discussed in Thread: DP83848T, , AMIC110


Hi Sitara Support Team,

My customer uses AM3357 and DP83848T on their custom board.
It connects "PR1_MII0_RXLINK(V2)" of AM3357 to "LED_LINK" of DP83848T
via "SN74LVC1G04DRLR" and "SN74CB3Q3245DGVR".

At first, LED interface of DP83848T is set in mode2 for blinking
when the transmitter or receiver is active during the LED blinking.
However the transmitter or receiver is not active during the LED blinking.

My customer has changed the mode that is not blinking
when the transmitter or receiver is active now.

Question:
How does the custom board have the proper LED LINK function?
Could you please let me know any check points?

Best regards,
Kanae

  • 0
    TI__Guru**** 393215 points
    Hi,

    It seems that the PHY is connected to the PRU MII. What software are you running?
  • 0 in reply to Biser Gatchev-XID
    Mastermind 9815 points

     

    Hi Biser,

    Thank you for your reply.

    The OS is μITRON and the application is a communication board by EtherCAT.
    Are there any points that my customer should verify for a realization of LED LINK function?

    Best regards,
    Kanae

  • 0 in reply to Kanae
    TI__Guru**** 393215 points
    Are they running the PRU EtherCAT firmware provided by TI?
  • 0 in reply to Biser Gatchev-XID
    Mastermind 9815 points
    Hi Biser,

    Yes, my customer uses the PRU EtherCAT firmware provided by TI.

    Best regards,
    Kanae
  • 0 in reply to Kanae
    TI__Guru**** 393215 points
    Thanks. I have notified the RTOS team. They will respond here.
  • 0 in reply to Biser Gatchev-XID
    TI__Mastermind 43296 points
    Hi Kanae,

    Have you checked the document www.ti.com/lit/an/spracc8/spracc8.pdf, section 4 Enhanced Link Detection to see if it helps?

    Regards,
    Garrett
  • 0 in reply to Garrett Ding
    Mastermind 9815 points

    Hi Garrett,

     

    Thank you for your reply.

     

     

    I checked the section 4 Enhanced Link Detection you recommended.

    Could I make sure the following items about the Enhanced Link Detection?

     

    1. The avobe document is described based on "DP83822” and "AMIC110" devices.

       My customer uses "DP83848T" and "AM3357" ,though, can it set the same function

       as the Enhanced Link Detection?

     

    2. The custom board connects "LED_LINK" of DP83848T to "pr1_mii0_rxlink" of AM3357

       and LED of EtherCAT connector as following image.

       Do you think that it is a proper connection for "Enhanced Link Detection"?

     

     

     

     

    3. If the answer of No.2 is "Yes", can it be checked the link status from MDIOLINK Register

       and "LINKSEL bit" in the MDIOUSERPHYSELn register of AM3357 after the MLINK/mii_rxlink detection?

       It may take 250 μs for a link loss reaction time.

     

    4. If the following check items are clear, the custom board can start to communicate

       and the LED of EtherCAT connector can blink for Active, can't it?

     

     -When it is selected LED mode "2" for DP83848T, LED_CNFG bit of PHY Control register is "0".

     

     -The polarity of the LED must be checked if the AN input is resistively pulled low

      then the corresponding output will be configured as an active high driver, or conversely...

     

     -DP83848T does not have "LED_SPEED" pin, so it can connect to GND.

     

     

    I am waiting for your comments.

     

    Best regards,

    Kanae

  • 0 in reply to Kanae
    TI__Mastermind 43296 points
    Hi Kanae,

    1. Yes. The enhanced link detection is basically to use the MLINK pin(pr1_mii0_rxlink) instead of MDIO internal state machine to detect link loss. The link status determination select (LINKSEL) bit in the MDIOUSERPHYSELn register determines the link status using the MLINK pin by setting it to 1.

    2. Yes, but you need to configure the LED_LINK MODE to 1 and LED_CFG[0] to 1.

    3. "LINKSEL bit" should be pre-set to 1 to determine link status using the MLINK pin. You can check the link status from MDIOLINK registers always and with MLINK pin detection, the link loss reaction time should be much lower than 250us.

    4. No, if you set the LED to mode 2 - blink for activity, the enhanced link detection mechanism will consider link loss when the LED is off and try to reconnect.

    Regards,
    Garrett
  • 0 in reply to Garrett Ding
    Mastermind 9815 points


    Hi Garrett,

    Thank you very much for your reply.
    I would like to just make sure the following my understanding is correct, or not?

    -If my customer would like to use the enhanced link detection function,
     he must select LED_LINK MODE "1", so LED_CNFG[0] of PHY Control Register must be set "1".

    -"LINKSEL bit" should be pre-set to 1 to determine link status using the MLINK pin.

    -My customer connection is no problem for the enhanced link detection function.

    Best regards,
    Kanae

  • 0 in reply to Kanae
    TI__Mastermind 43296 points

    Kanae,

    Yes, your understanding is correct.

    DP83848 doesn't have the 'fast link down' feature as in DP83822 and TLK11x PHY. This is probably the reason that 'it may take 250 μs for a link loss reaction time.'

    Regards,
    Garrett