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DP83867E: BMSR Adress

Hiroaki Yuyama TED
Expert 1720 points
Part Number: DP83867E

Tool/software:

Dear, Ethernet PHY Support team.
In the data sheet, Table 7-11, Address 0x0001 bit 6 (MF PREAMBLE SUPPRESSION) says, "0 = Normal management operation.
The device requires a minimum of 500ns gap between two
transactions, followed by one positive edge of MDC and MDIO=1,
before starting the next transaction."

I think this bit can only be used with the value set to "1 (Preamble Suppression enabled)."
(As you can guess from the name, it's a function that allows you to send Ethernet frames without the preamble that should be at the beginning of the frame!?)

I think I have a basic understanding of preambles.

What is the difference with Bit6=0 "Normal management operation"?
I would like to know what state it is in when used with Bit6=0 "Normal management operation".
Best Regards,
Hiroaki Yuyama
  • 0
    TI__Genius 13026 points

    Hi Yuyama-san, 

    The preamble mentioned for this bit is for the management transaction. Like ethernet frames, the MDIO/MDC transaction sends preamble used by the PHY to establish synchronization with the MAC before receiving a management frame. This preamble is followed by an opcode and other data to configure the PHY. 

    If the preamble suppression is enabled, the PHY will not expect a preamble and immediately expect the MAC to send valid opcode and turnaround.

    In normal operation, the PHY will expect a 32-bit preamble to synchronize with the MAC and then expect valid data to come in to the PHY for configuration. 

    Please let me know if you have any other questions. 

    Best,
    J

  • 0 in reply to J
    Expert 1720 points

    Hello J-san,

    Thank you for your reply.
    We have sent our reply back to the customer.
    Please let us know if you have any further questions.

    Best Regards,
    Hiroaki Yuyama

  • 0 in reply to Hiroaki Yuyama TED
    TI__Genius 13026 points

    Hi Yuyama-san,

    Please let me know if the customer has more questions.

    Best,

    J