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DP83869HM: Dual 1Gbps Media Converter Application

alex r
Prodigy 30 points
Part Number: DP83869HM

Tool/software:

Hallo TI-Team,

we developed a hardware with two DP83869HM in unmanaged 1Gbps Media Converter Mode as shown in the following figure:

The Prototype works fine if Near & Far End Link Partner support 1Gbps.

However, it does not work if Near & Far End Link Partner support only 100Mbps.

In that second case, link is up but there is no actual data-traffic.

As Customer would like to use both Near & Far End Link Partner Rate capabilities, the question is if desired function

could be implemented in 1Gbps Media Converter mode or if function mode straps need to be changed to 100Mbps Media Converter mode in second case.

Or in other words: Can DP83869HM unmanaged 1Gbps Media Converter Mode be used for 100Mbps mode as well?

Straps are set the following way:

-Functional - Mode: 1000Base-T to 1000Base-X

- Fiber: Auto-Negotiation  

-Copper: Auto-Negotiation 1000/100, Auto MDIX

-Copper: Mirror Disabled

-Link Loss Pass Thru Enabled  

  • 0
    TI__Genius 12531 points

    Hi Alex,

    For 100M media converter, the device has to be strapped to 100M media converter. 1000M media converter mode cannot support 100M.

    Best,

    J

  • 0 in reply to J
    Prodigy 30 points

    Hi J,

    thank you for the fast response. Alright, understood.

    One last question:

    Whats the purpose of Straps ANEGSEL_0 & ANEGSEL_1 in 1000M Media Converter Mode then?

    Datasheet shows option there the change Copper Advertisement between 1000 & 1000/100.

    Why would Copper Interface possibly advertise 1000/100 if 100 would never work?

  • 0 in reply to alex r
    TI__Genius 12531 points

    Hi Alex, 

    I am checking this internally. I will get back to you once I have some response from the team. 

    Best,
    J

  • +1 in reply to J
    TI__Genius 12531 points

    Hi Alex, 

    Auto-negotiation for speed change on media converter mode is one of the features that was considered, but it was decided not to be implemented. The strap table you see is one of the vestiges of it. 

    Best,
    J

  • 0 in reply to J
    Prodigy 30 points

    Hi J,

    alright, thank you.

    Maybe TI-Team could update this information in Datasheet as its somewhat misleading when using DP83869HM in unmanaged Mediaconverter Mode.