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DP83867CS: DP83867CS auto-negotiating strap setting problem with K2L

Zeb
Intellectual 380 points
Part Number: DP83867CS

Hi,

Part number DP83867CS and autonegotiation enable / disable: In datasheet page 37, configuration strap for autonegotiation (RX_CTRL) control is a bit confusing. I have set the mode=1. Strap function for this bit is named as 'Autoneg Disable' and therefore I am setting this to mode=1 (value in mode 1 is 0 and therefore meaning 'Autoneg disable' is disabled -> in practise Autoneg should therefore be enabled).

Problem is that in Linux while we read the STRAP_STS1 register values, we get FFEA where the bit 7 is set. Now on page 79, bit 7 with value 1 means that Auto-Negotiation is strapped to disable.

So there is a mistake either in the datasheet or in reading the strap values in the startup. To confirm this, could you quickly check the datasheet if there is a mistake. 

If it means anything, our processor is the K2L keystone 2 processor.

  • 0
    TI__Mastermind 18425 points
    Hello,

    Your interpretation is correct. When Autoneg_Disable is 0, auto-negotiation should be enabled. I think the problem here is that the PHY might be getting strapped to a different mode on power-up. This can happen due to internal pull resistors on the MAC. Can you verify what is the voltage on the RX_CTRL pin during power up? Another debug step would be to check if the processor has any internal pull-up resistors.
    Also please change strap on RX_CTRL to mode 3. If changing strap to mode 3 is not possible then please clear bit[7] of register 0x31 to 0.

    -Regards,
    Aniruddha