• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 416 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

DP83822I: Loopback

Toshihiro Watanabe
Genius 10235 points
Part Number: DP83822I

Hello,

We would like to know below items.

1) Does Loopback feature guaranteed function?

2) Near-End Loopback doesn't describe in Figure 28. I think all loopback in figure 28 except for external loopback can do by selecting BISCR register. Is my understanding correct?

3) External loopback doesn't include Near-end loopback, right?

4) Is it possible to use DP83822 for link partner with external loopback? If possible, is the setting that link partner DP83822 is near-end loopback?

5) If we want to do external loopback without link partner, is it ok to connect TX-RX short connector at RJ-45 connector?

6) Please let us know if there is a limitation for loopback mode.

Best regards,

Toshihiro Watanabe

  • 0
    TI__Mastermind 26320 points
    Hi,

    1. I am not sure what do you mean by "guaranteed function". Loopback for MII is defined in IEEE standard. The primary use of this feature is smooth bring-up of MAC and MDI interface during development.

    2. Yes, all near end loopback can be enabled using register configuration thru BISCR.

    3. External loopback is board level loopback using external cross connections from TX to RX.

    4. I am not sure I got your questions. Can you please elaborate what you are trying to achieve ? I can accordingly help you with recomendation.

    5. Yes, you can short TX with RX for external loopback.

    6. Not sure , what kind of limitations you are referring to here.

    Regards,
    Geet
  • 0 in reply to Geet Modi
    TI__Genius 10235 points
    Hello Geet-san,
    We are thinking to use loopback functionarity for self-diagnosis. If loopback function worked is not guaranteed, we can't use loopback for self-diagnosis.

    Regarding the question 4, external loopback is typically done by TX-RX shorted. If it is not TX-RX short but connect DP83822 as load/partner.
    Is it possible to loopback by using this load/partner DP83822? If yes, loopback function used?

    Regarding 6, if there is a limitation for example, loopback can't work if a function used. If there is no limitation, it is ok.
    Best regards,
    Toshihiro Watanabe
  • 0 in reply to Toshihiro Watanabe
    TI__Mastermind 26320 points
    Hi,

    Understand. Yes, please use loopback for self-diagnosis.

    Yes, that's possible, you have to enable loopback in Load/partner to send the data back.

    Loopback function as stated in datasheet.

    Regards,
    Geet