• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 33 subscribers
  • Views 212 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.

DP83TC812S-Q1: DP83TC812 SGMII autonegociation

Alexandre Bruliau
Prodigy 30 points
Part Number: DP83TC812S-Q1

Tool/software:

Hello, 

I am using the ethernet phy DP83TC812 in sgmii mode.

I know that SGMII autonegociation can be disabled since its only support a fixed speed and full duplex.

However, I would like to understand more what represent the timer value for SGMII Autonegociation between the MAC and the PHY.

Does the SGMII timer for the MAC side should be set accordingly ? 

What is the difference between SGMII autocompleted and SGMII link flag when reading SGMII status ?

Best regards, 

Alex

  • 0
    TI__Mastermind 26832 points

    Hi Alex,

    The default auto-negotiation timer value of DP83TC812 is 2us. This value can be increased in register 0x608 bits[2:1]. The timer value on the MAC side should be equal or greater than that of the PHY.

    The SGMII link status bit shows if SGMII link is actively up. This can be asserted regardless of SGMII-autonegotiation enable/disable. SGMII auto-negotiation completed bit will not be asserted if SGMII auto-negotiation is disabled.

    Thanks,

    David

  • 0 in reply to David Creger
    Prodigy 30 points

    Hello David, 

    thanks for your quick reply.

    Should I actually wait for the SGMII link up flag to be asserted before sending ethernet frames from the MAC, or the autonegociation completed flag is enough ?

    What is that timer actually represent, I mean is it just a timeout window during which sgmii autonegociation has to be completed ? 

    Best regards,

  • 0 in reply to Alexandre Bruliau
    TI__Mastermind 26832 points

    Hi Alex,

    Yes, you should ensure that SGMII link is up before sending Ethernet frames from MAC. 

    The timer is a timeout window for each SGMII partner to complete negotiations, yes.

    Thanks,

    David