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Original question:

DP83869HM: Pin States

DP83869HM: Mirror Mode

Bettina Wyss
Prodigy 50 points

Part Number: DP83869HM

Hi,

we would like to use the mirror mode feature of the DP83869HM to simplify the routing. However, we are unsure if this feature has an impact on the Auto-MDIX feature? 

And I have no clue which registers are meant with this: "When using mirror mode in
100-Mbps mode, TI recommends that the user read register 0xA1 and write the same value in register A0h."

What registers? I can't find that in the datasheet? And does this "read and write regs" also apply when using auto-neg? 

Thank you for your help

Betty

  • 0
    TI__Genius 13946 points

    Hi Betty,

    Bettina Wyss said:
    we would like to use the mirror mode feature of the DP83869HM to simplify the routing. However, we are unsure if this feature has an impact on the Auto-MDIX feature? 

    Auto-MDIX will be supported in mirror mode for both speeds, so there is no impact. 

    Bettina Wyss said:

    And I have no clue which registers are meant with this: "When using mirror mode in
    100-Mbps mode, TI recommends that the user read register 0xA1 and write the same value in register A0h."

    What registers? I can't find that in the datasheet? And does this "read and write regs" also apply when using auto-neg? 

    Let's say you read register 0x00A1 = 0x1, then you should write the value 0x1 to register 0xA0 (note this step is only recommended for 100 Mbps mode).

    If you want to enable mirror mode, you may do so through straps or through register configuration using the Port Mirror Enable bit in the CFG4 register (address 31h).

    Auto-negotiation is enabled by default, so you do not need to write to any registers to use it. 

    Best regards,

    Melissa