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DP83869EVM: DP83869 in Media Converter mode

Frank Fulcher
Prodigy 10 points
Part Number: DP83869EVM


Tool/software:

Hi

I am trying to get the DP83869EVM to work in media converter mode but don't get a connection at the Fiber end. Can you help?

I am using a Gigabit Ethernet (1000BASE-BX10) CWDM Bidirectional SFP transceiver from OE Solutions part no. RBT12SVX-I49 plugged into J3 on the fiber side and a ethernet cable plugged in to J20 that goes to the copper interface on a Versalogic Raven SBC.

I have the OPMODE links set to 1 0 0 for 1000Base-T to 1000Base-X (ie. media converter mode ?) and LED links set to 0 0 0 for Auto-negotiation, 1000/100/10 advertised, Auto MDI-X.

The MIRROR_EN link is also fitted but I don't think this is relevant ?

I am using a 12V power brick plugged in to J25 jack. I am pretty sure I have all the jumper links set correctly on sheet 5 of the schematic as the power leds light up. But could you confirm what these should be set to please ?

On power-up I briefly see Link Led come on and then go off after a few seconds. The only way I can get Link solid on and Activity led solid on is if I change OPMODE to either RGMII to Copper or SGMII to Copper.

I know that the SFP is detecting the laser source as it's LOS output pin (connected to JTAG_TDI input to phy) goes solid low when I plug in the LC fibre cable.

Also the SFP_TX_DISABLE was at mid-rail (1.6V) due to a 4k7 pull-up inside the SFP, so I changed R26 pull down from 4k7 to a 0R to ensure the SFP TX was enabled but this made no difference

Is there anything else in my setup that is wrong?

Thanks

Frank 

 

  • 0
    TI__Genius 15116 points

    Hi Frank,

    Auto-negotiation strap setting and default LED setting are different when you are in media converter mode. Please refer to the datasheet section 7.5.1.3 and 7.5.1.9. If your copper connection is not mirrored, enabling mirror mode will not establish connection on the copper side.

    Could you also describe which LEDs are turning on, and if they turn on and stay on or if they blink?

    Could you send us the register dump from 0x00 to 0x1F to better look into this?

    Please let me know.

    Best,

    J 

  • 0 in reply to J
    Prodigy 10 points

    Hi J

    Thanks for the prompt reply.

    Referring to section 7.5.1.3, at power up (OP_MODE 100) LED0 comes stable ON for a few seconds and then goes off. LED1 and LED2 are always off. This indicates Copper link up for a few seconds and fiber link never up.

    Referring to section 7.5.1.9 

    LED_0 set to 0 for Fiber Auto Neg

    LED_2 and _1 set 00 for Copper Auto-Neg (1000/100)

    RX_CTRL set to 1 for MIRROR_EN but I am not sure if the copper connection is mirrored, I'll check on Monday

    RX_CLK set to 0 Link Loss Pass Thru enabled

    As for LED behaviour they are as described above - only LED0 comes on for a few seconds then goes off and stays off. LED1 and LED 2 always off in this mode.

    Sorry haven't got the USB2MDIO utility installed on a laptop yet so cannot read the registers. I'll talk to IT to get this done next week.

    Thanks

    Frank

  • 0 in reply to Frank Fulcher
    TI__Genius 15116 points

    Hi Frank, 

    Thank you for your response. I think mirror mode may be the issue since most typical copper connections are not mirrored. This can cause link failure. 

    Please let me know after trying to disable the mirror mode. 

    Best,
    J