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DP83867CS: Auto negotiation and configuration resister

Michiaki Tanii
Expert 4350 points
Part Number: DP83867CS

Hello team,

Here is the inquiries from customer

 

  1. In auto-negotiation and link-up with giga bit, are there any problem if NP(bit15) in ANAR (Table.9、Addr0x0004) resister isn’t used ?
    Their configuration is as following
    - Configuration ANAR resister (Enable 10BASE-T, 100BASE- T)
    - Configuration CFG1 resister (Enable 1000BASE-T)
    - Execution auto-negotiation restart
    - After link up, getting PHYSTS resister and confirm link-up speed.
    (Customer think that all configuration is done for communication with Gbit for PHY at link-up)
  2. If the above understanding is correct, what purpose is Next Page ?
    They can’t understand how to use it.
  3. If NP bit is off, it can linkup with Gbit at execution auto-negotiation restart but if AN bit is on and execute auto negotiation restart, link up is failed and SPEED DUPLEX RESOLVE bit in PHYSTS resister is remained off.
    If NextPage is used, are there any procedure in auto negotiation restart ?
  4. Reading linux driver of competitor’s PHY, PHY RESET is executed when delay or auto negotiation configuration is changed.
    Does our PHY require similar configuration ?
    If yes, if which configuration is changed, customer needs RESET ?
  5. If RGMII_TX_CLK_DELAY and RGMII_RX_CLK_DELAY are set, the configuration in RGMIIDCTL resister is enable ?]
  6. If auto negotiation is not used, customer wants to use fixed configuration, is it ok to only disable AUTO NEGOTIATION ENABLE and configure their target speed and duplex in SPEED SELECT and DUPLEX MODE ?

 

Thank you and best regards,

Michiaki

  • 0
    TI__Mastermind 26320 points

    HI,

    1.  NP bit is automatically enabled/disabled by PHY as per IEEE standard requirement and don't need to change. I recomend you selecting only the speed you want to broadcast in ANAR.

    2.  Next Page : Please refer to IEEE 802.3 spec for details

    3.  As described above, you need to enable the PHY speed to broadcast

    4. For Auto-Cong change, minimal Auto-Negotiation restart or PHY restart is needed. For Delay configuration, not restart is needed

    5.  Correct

    6.  In Gigabit speed, Force mode is not supported by IEEE standard. PHY shall be used with Auto-Negotiation mode only.

    Regards,
    Geet

  • 0 in reply to Geet Modi
    TI__Expert 4350 points

    Hi Geet, 

    1.  NP bit is automatically enabled/disabled by PHY as per IEEE standard requirement and don't need to change. I recomend you selecting only the speed you want to broadcast in ANAR.

    -> Please let me double check that customer doesn’t need to configure NP bit but need to configure the speed and duplex. Is it correct ?

    -> Is it ok that customer configure CFG1 resister for Gbit advertisement ?

     

    4. For Auto-Cong change, minimal Auto-Negotiation restart or PHY restart is needed. For Delay configuration, not restart is needed

     

    -> When Auto-Negotiation configuration is changed and restart, customer needs reconfiguration for delay and FIFO ?

     

    If RGMII_TX_CLK_DELAY and RX_CLK_DELAY is not set (off), the number of delay will be typ 2.00ns ?

     

    Thank you and best regards,

    Michiaki

  • 0 in reply to Michiaki Tanii
    TI__Mastermind 26320 points

    HI,

    1. If they have configured the correct straps, the PHY does advertise the 1000Base-T and Full Duplex. They don't need to make any register change. They can read and confirm.

    2. The delay needs to be configured only if PHY is Reset ( Pin or HW reset thru register). Else the PHY retains the configuration register across auto-Negotation.

    3. The Delay settings are dependent on the way registers are configured. If you enable both TX and RX, yes the default is 2 ns.

    Regards,
    Geet