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DP83867ERGZ-S-EVM: About wiring of MDI terminal and RJ45 terminal

TOSHIKAZU HORI
Prodigy 140 points
Part Number: DP83867ERGZ-S-EVM
Other Parts Discussed in Thread: DP83867E

Tool/software:

Thank you for your help.

Please advise me on how to wire the MDI terminal and RJ45 terminal of this evaluation board.

RJ45 pinout (T568B standard)
1. Pin 1 (TX_D1+): White-orange
2. Pin 2 (TX_D1-): Orange
3. Pin 3 (TX_D2+): White-green
4. Pin 4 (TX_D3+): Blue
5. Pin 5 (TX_D3-): White-blue
6. Pin 6 (TX_D2-): Green
7. Pin 7 (TX_D4+): White-brown
8. Pin 8 (TX_D4-): Brown

DP83867E MDI terminal
1. Pin 1: TD_A_P: Positive signal of pair 1
2. Pin 2: TD_A_N: Negative signal of pair 1
3. Pin 4: TD_B_P: Positive signal of pair 2
4. Pin 5: TD_B_N: Negative signal of pair 2
5. Pin 7: TD_C_P: Positive signal of pair 3
6. Pin 8: TD_C_N: Negative signal of pair 3
7. Pin10: TD_D_P: Positive signal of pair 4
8. Pin11: TD_D_N: Negative signal of pair 4

T568B standard connection example
1. RJ45 pin 1 (TX_D1+): Pin1 TD_A_P of DP83867E
2. RJ45 pin 2 (TX_D1-): Pin2 TD_A_N of DP83867E
3. RJ45 pin 3 (TX_D2+): Pin4 TD_B_P of DP83867E
4. RJ45 pin 6 (TX_D2-): Pin5 TD_B_N of DP83867E
5. RJ45 pin 4 (TX_D3+): Pin7 TD_C_P of DP83867E
6. RJ45 pin 5 (TX_D3-): Pin8 TD_C_N of DP83867E 
7. RJ45 pin 7 (TX_D4+): Pin10 TD_D_P of DP83867E 
8. RJ45 pin 8 (TX_D4-): Pin11 TD_D_N of DP83867E 

Evaluation board connection
1. RJ45 pin 1 (TX_D1+): Pin1 TD_D_P of DP83867E 
2. RJ45 pin 2 (TX_D1-): Pin2 TD_D_N of DP83867E 
3. RJ45 pin 3 (TX_D2+): Pin4 TD_C_P of DP83867E 
4. RJ45 pin 6 (TX_D2-): Pin5 TD_C_N of DP83867E 
5. RJ45 pin 4 (TX_D3+): Pin7 TD_B_P of DP83867E
6. RJ45 pin 5 (TX_D3-): Pin 8 TD_B_N of DP83867E
7. RJ45 pin 7 (TX_D4+): Pin 10 TD_A_P of DP83867E
8. RJ45 pin 8 (TX_D4-): Pin 11 TD_A_N of DP83867E

The MDI pair signal wiring of the evaluation board seems to be different from the standard connection example of the T568B standard, but should this pair wiring be taken into consideration in the actual design?

If possible, I would like to connect based on the T568B standard to ensure design consistency, but is there any problem?

Thank you in advance.

  • 0
    TI__Mastermind 32815 points

    Hello,

    For my understanding, T568B is taking your pair A and B and crossing them, while not touching pair C and D. Are both sides of the cable T568B, or is it mismatching? Perhaps a diagram would help.

    Sincerely,

    Gerome

  • 0 in reply to Gerome Cacho
    Prodigy 140 points

    Hi Gerome,

    Thank you for your reply.

    Specifically, I am concerned that the EVM wiring diagram and the wiring diagram on the data sheet are different, as shown in the figure below.

           Fig.1 EVM Wirling Diagram

    　　Fig.2 Datasheet Wirling Diagram

    In order to maintain design consistency (T568B wiring!), I would like to use the wiring on the data sheet unless there is a problem, but I would like to know if there is a special reason to use the EVM wiring.

    Thank you in advance.

  • 0 in reply to TOSHIKAZU HORI
    TI__Mastermind 32815 points

    Hello,

    This is due to the mechanical constraints of the EVM. If you notice, the pairing of RJ-45 will be flipped depending if the RJ-45 is mounted on the same plane or opposite as the PHY. The PHY has a neat feature to be able to counteract this, Mirror Mode, which will flip MDI pairs A-D on its head.

    Sincerely,

    Gerome

  • +1 in reply to Gerome Cacho
    Prodigy 140 points

    Hi Gerome,

    Thank you for your confirmation and reply.

    I understand that this is due to the mechanical constraints of the EVM.

    As long as it can be confirmed that there is no special electrical meaning, there is no problem. Thank you.

    I think there is a high possibility that we will also refer to the EVM at the wiring design stage.

    This is helpful.

    Thank you very much.