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DP83848 timing from powerup/reset to auto negotiation.

Wade Vonbergen
Guru 62930 points

Looking for minimum timing on DP83848 from reset_n de-assertion to auto-negotiation pulses.

And consequently is there enough time after a reset for auto-negotiation to be disabled via the management interface before any auto-negotiation actually takes place?

Thanks,
Wade

  • 0
    TI__Mastermind 19780 points
    Hi Wade,

    I will have to get back to you about the minimum time from reset_n de-assertion to auto-neg pulses.

    If this makes your life easier, you can strap the AN_EN line to 0 to disable auto-negotiation and force 10/100 full duplex or half duplex modes as the application demands to simply avoid auto-neg pulses all together.

    See section 6.3.1.1 of the datasheet here: www.ti.com/.../dp83848i.pdf


    Best Regards,
  • 0 in reply to Rob Rodrigues
    TI__Guru 62930 points
    Rob,
    Thanks.
    I have advised on disabling auto negotiation, and this was not desired.
    Any update on the timing?
    I am assuming that auto-negotiation could be re-enabled via software even if strapped to disabled. Can you confirm?

    Thanks,
    Wade
  • 0 in reply to Wade Vonbergen
    TI__Mastermind 19780 points
    Wade,

    No update on the minimum timing yet.

    Yes, auto-negotiation can be restarted even if strapped as disabled. Straps are sampled at power up and reset, and write into the control registers once. These can be overwritten during normal operation.

    Only strap option I know of that can't be changed via MDIO is the Phy's MDIO address.

    Best Regards,