• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 34 subscribers
  • Views 191 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.

DP83869HM: Speed optimization vs Enhanced mode

Kai Nomiyama
Expert 5575 points
Part Number: DP83869HM

Hi Team,

I have two question about Speed optimization and enhanced mode.

[Question 1]
When we try link establishment under below setting, Channel C/D doesn't have any energy so Phy - Link partner establish 100M link right since bit[8] = 1?
> 100M Base data rate, Alternative A support, GEN_CFG2 Register (Address = 0x14) bit[9] = 0, bit[8] = 1

[Question 2]
when use 2 pairs LAN cable for 1000M link establishment by exchanging FLP, we fail Auto-negotiation.
After Auto-negotiation failure, DP83869HM tries 4 attempts(default) 1G link establishment.

If DP83869HM fails 4 attempts, DP83869HM tries 100M link establishment by exchanging FLP then establish 100M link or DP83869HM and Link partner already knows both supporting 100M during 4 attempts so immediately establish the 100M link?

in such case,
if we set enhanced mode, DP83869HM allow Fast link drop so we can reduce T1 window?
> GEN_CFG2 Register (Address = 0x14) bit[9] = 0, bit[8] = 1

if we don't set enhanced mode, Fast link drop doesn't work so we have to wait T1 window?

Regards,
Kai

  • 0
    TI__Genius 16030 points

    Hello Kai,

    I am checking with team here and will reply back.

    --

    Regards,

    Vikram

  • 0 in reply to Vikram Sharma
    TI__Genius 16030 points

    Hello Kai,

    Here are the answers: 

    [Answer 1] : If 100Mbps speed is forced then yes PHY will directly establish link @100Mbps. If bit 9 is 0 and speed is not forced, then normal auto-neg flow gets followed.

    [Answer 2] : If the speed is forced then PHY will try to form link for the programmed speed only.If bit 9 is 0 and speed is not forced, then normal auto-neg flow gets followed.

    Also enhanced mode feature is only effective when PHY is trying to "establish" link. FLD feature is only effective when PHY is deciding on when to declare that link is dropped. For FLD to become active a good link has to get established first.

    --

    Regards,

    Vikram