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DP83822I: Auto Negotiation + Auto MDIX + Robust Auto MDIX configuration

Part Number: DP83822I

Hi Experts,

I am confusing how to use DP83822 in forced mode.

I posted below to confirm whether we can use AUTO-MDIX when Auto Negotiation is disabled. The answer is that Auto-MDIX can work by set Auto MDI/X Enable bit in PHYCR register even when Auto negotiation is disabled.

On the other hand, below thread said as below.

. For the DP83822, you will lose link if you have enabled auto-neg + forced mdi/mdix OR forced speed + auto-mdix you will either have to have both forced modes or both auto enabled.

In other thread, Robust Auto MDIX bit should be set when Auto negotiation is disabled.

My question is which of below options are correct.

# Auto-Negotiation Enable Auto MDI/X Enable Robust Auto MDIX
1 0 1 1
2 0 0 1

Regards,

Uchikoshi

  • Hi Uchikoshi,

    The following settings are ok when auto-negotiation is disabled.

    Auto-Negotiation Enable Auto-MDIX Enable Robust Auto-MDIX
    0 0 0
    0 1 1

    If auto-negotiation is disabled, Auto-MDIX should also be disabled. If auto-MDIX is desired, both Auto-MDIX and Robust Auto-MDIX should be enabled. 

    Thank you,

    Nikhil