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DP83640T-EVK: DP83640 with SFP

Adrien Somoza
Prodigy 30 points
Part Number: DP83640T-EVK
Other Parts Discussed in Thread: DP83640

Hello,

we are trying to use DP83640T devboard with a SFP module. We succeeded in using it with copper, but with SFP, it seems there is no communication. 

First of all, we didn't found how to connect "Signal Detect" from SFP as it was written on devboard user guide (R128).

Then, it seems that our board is not forced into 100M mode as LED "Link" is blinking continuously.

FYI, we are using Microchip Harmony.

Thanks in advance for your help

  • 0
    TI__Mastermind 18425 points
    Hi Adrien,

    Are you using a different SFP module than what is mentioned in the EVM schematics? Does it not have a Signal Detect pin?

    Also, can you read the PHY registers? Reading register 0x00 should tell you if the PHY is strapped to force 100M or not.

    -Regards,
    Aniruddha
  • 0 in reply to Aniruddha Khadye
    Prodigy 30 points

    Hi Aniruddha,

    thank you for your answer.

    The fiber optic module mentioned in the EVM schematics is AFBR-5803Z. It 's an old form factor of optical fiber module (GBIC) that has been replaced by SFP. The SD pin appear in Gbic module pinout but not in SFP, that's why I'm asking you where do I have to make this link "signal detect".

    I'm not able to read PHY register yet. But with led indicators, I can see that the PHY is still in 10M mode, even if FX_EN_Z is pulled down to the GND.

  • 0 in reply to Adrien Somoza
    TI__Mastermind 18425 points
    Hi Adrian,

    FX_EN_Z strap is on the RX_ER pin which is connected to PIC. Can you check if PIC has any internal pull resistor on this pin?
    We have a software utility which will allow you to connect to TI Ethernet PHY EVMs and read/write register. You can download it from : www.ti.com/.../USB-2-MDIO
    To use this software, you would need a MSP430 launchpad and 3 wires with header connectors to connect to MDIO, MDC, and Ground on the DP83640 EVM. Register access will help with the debug process.

    -Regards,
    Aniruddha
  • 0 in reply to Aniruddha Khadye
    Prodigy 30 points

    We found the problem: the pull-up and pull-down resistors between PHY and fiber controller are not welded on default copper setup (R126,R127,R129,R136,R137,R122,R123,R132,R133,R120,R121). Once we added these, it was working correctly.

    Please note that both following documents don't specify this modification between copper and fiber mode.

    Thanks for your help Aniruddha