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DP83640: the issue about disconnection of the fibre port

user6242464
Prodigy 20 points
Part Number: DP83640

Hi,

This is Zihao, and recently I was handling the issue about the two different port connected to the CPU boards, one is the fibre ethernet which could be found from the PC, however the other one is the ethernet port which failed.

In the last few days, I recorded the graph of MDIO and MDC of these two different board, and found that the data was different in device address, register data, which shown below,

ethernet port: 1 01 10 00000 00001 10 0111 1000 0000 1001 1

fibre port       : 1 01 10 00001 00001 10 0111 1000 1100 1101 1

from the data, it seemed that fibre should be in the correct condition, however it is not.

Now I am trying to test the data from other pins for DP83640, which is TX_EN, TXD_0, TXD_1, RXD_1, RXD_0, RX_ER. But unfortunatly, I got nothing from them.

I wonder there would be some methods to communicate with the DP83640, therefore I could record the data from the pins above.

please help me .

Zihao

  • 0
    TI__Genius 11900 points

    Hello Zihao,

    The PHY address is a 5 bit address. The MDIO and MDC is used to access the registers of the PHY and edit/read the configuration.

    What register did you read using the MDIO/MDC lines, each register is 16-bits. I do not understand what data you have on the Ethernet and fiber port.

    Please give me more information. Take a look at https://www.ti.com/lit/ds/symlink/dp83640.pdf

    Thanks,

    Vibhu

  • 0 in reply to Vibhu Vanjari
    Prodigy 20 points

    hi, 

    Thanks for replying.

    From the datasheet, it is said that the Typical MII MDIO format should be like below

    MII Management Serial Protocol <idle><start><opcode><device addr><reg addr><turnaround><data><idle>
    Read Operation                            <idle><01><10><AAAAA><RRRRR><Z0><xxxx xxxx xxxx xxxx><idle>
    Write Operation                           <idle><01><01><AAAAA><RRRRR><10><xxxx xxxx xxxx xxxx><idle>

    and I found there were three bits different in the data part which confused me a lot.

  • 0 in reply to user6242464
    TI__Genius 11900 points

    Hello Zihao,

    Thanks for the clarification. Bits 7 and 6 are are read-only bits that are permanently set to a default value. Looks like these are corrupted on Ethernet Copper device. Bit 2 indicates that there is no link on this board as well.

    Does power-cycling this PHY and reading this register also give you the same values?

    "from the data, it seemed that fibre should be in the correct condition, however it is not." How do you know it is not? From the register values it looks like there is link established on fiber and actually broken on the Ethernet port.

    Thanks,

    Vibhu