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DP83869HM: Use of DP83869HM for 1000Base-KX to 1000Base-T in Media Converter Mode

Justin Muzzy
Prodigy 10 points
Part Number: DP83869HM

Tool/software:

Greetings,

I read in an old TI forum post that the DP83869HM may successfully connect with a 1000Base-KX connection (i.e., from a backplane MAC/PHY copper SERDES connection to the SIP/N and SOP/N pins) IF the auto-negotiation is disabled on both the device and link partner and speed forced to Gbe.

Can you please reverify this is correct before I begin my design with this part?

I would need to disable fiber auto-negotiation either by strapping (LED_0 - Pin #47 high), or set register BCMR Bit 12 = 0.  Is this correct??

Do I need to also disable the "Signal Detect" pin either by strapping (LED_1 - Pin #46 low/GND), or set register CFG_FX_CTRL0 Bit 9 = 1 - ?? 

(This is because there is no Signal Detect line coming from the copper backplane SERDES MAC/PHY on the 1000Base-KX link partner.)

Are there any other settings I need to strap for this connection to function correctly?

Thank you for any help!

Justin

  • 0
    TI__Mastermind 19591 points

    Hi Justin,

    You heard correctly, but please note that 1000Base-KX has not been validated or characterized in house with any of our Ethernet PHYs.

    The main advice I would give is to evaluate first with MDC/MDIO connected for register access. Having access to the PHY's registers will make debugging easier. We've seen a mixed bag of customer's achieving 1000Base-KX by using SGMII (still the same pins, SIP/N & SOP/N). Signal detect should be disabled, for the reasons that you mentioned.

    Regards,

    Alvaro