• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 405 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: Speed Status bit is updated as soon as LINK is established?

Hisao Uchikoshi
Genius 14850 points
Other Parts Discussed in Thread: DP83822I

art Number: DP83822I

Hi Experts,

Assuming using auto-negotiation.

Below is the capture from PHY Status Register(PHYSTS) for DP83822.

Below is the capture for DP83848. In case of DP83848, SPEED STATUS bit is updated when auto-negotiation is completed.

Is Speed Status bit for DP83822 updated when LINK is established? Can we consider that a software does not need to wait Auto-negotiation complete?

Regards,

Uchikoshi

  • 0
    TI__Mastermind 18425 points
    Hi Uchikoshi-san,

    The Speed Status bit is valid only when there is a valid link. When a valid link is established, this bit will be updated based on 100Mbps or 10Mbps link. But in order to achieve link up, autonegotiation process has to be completed. When auto-negotiation is on, link up cannot be achieved without auto-negotiation completion. So the software will have to wait to auto-negotiation is done.

    -Regards
    Aniruddha
  • 0 in reply to Aniruddha Khadye
    TI__Genius 14850 points
    Hi Aniruddha,
    I am sorry that I posted the same picture on the first post. I updated it for DP83822 so please see it again.
    The note what I highlighted is not existing for DP83822. I want to know if this is correct.

    Below is a background for this inquiry:
    As far as looking at DP83848 behavior, "AUTO-NEG COMPLETE" flag of PHYSTS register is set to 1 about several hundred mill seconds after "LINK STATUS" bit of PHYSTS register is set to 1. Though a original software attempted to read "SPEED STATUS" bit just after "LINK STATUS" bit becomes to 1, "SPEED STATUS" bit was not updated to an actual Link speed data. Thus, we added a loop code to wait "AUTO-NEG COMPLETE" flag becomes to 1 then read "SPEED STATUS" bit.
    I am wondering if this loop is sill required for DP83822.

    Regards,
    Uchikoshi
  • 0 in reply to Hisao Uchikoshi
    TI__Mastermind 18425 points
    Hello Uchikoshi-san,

    That particular test has not been performed on DP83822. I would recommend checking both link status and auto-negotiation status.

    -Regards
    Aniruddha