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DP83TD510E: PHY configuration for APL conformity & certification

Petr Sulima
Prodigy 20 points
Part Number: DP83TD510E

Tool/software:

Hello,

we are working on APL device prototype (Spur device capable on 1V operation only). 

We use the DP83TD510 PHY in our APL prototype.

Our configuration at startup

  1. 1V mode (PMA_CTRL.Bit12 = 0)
  2. Ability bits set according to spur port specification (AN_CTRL_10BT1 = 0x8000)
  3. Enable AN (AN_CONTROL:mr_an_enable = 1)
  4. Master mode (PMA_PMD_CTRL.cfg_master_slave_val = 1)
  5. Software reset

 

With this base configuration we can establish a link with various devices (2 different 10Base-T1L switches, 1 evaluation kit with a different PHY, and with the DP83TD510 EVM)

 

Later, we change the AN and master/slave configuration as described below depending on external switches.


We have two major problems:

  1. When the AN is disabled (AN_CONTROL:mr_an_enable = 0), the output changes to 3PAM signal, which is not correct according to APL testers. This is observed directly on DUT without the link partner connection (with added 100 Ohm termination)
  2. When the AN is disabled and slave mode is enforced (PMA_PMD_CTRL.cfg_master_slave_val = 0, AN_ADV_1.Bit12 = 1) the PHY becomes completely silent, and the link cannot be established with any of the above-mentioned partners.

 

What we need:

To pass the APL test 146.3.1 (PCS Transmit Signaling). We fail at first step when the link should be established with the AN disabled and DUT set as SLAVE.

Are the steps described above correct in general?
Is there any other approach how to reach the state required by the APL test?

Thank you in advance for a support.

Kind regards,

Petr Sulima

  • 0
    TI__Mastermind 25955 points

    Hi Sulima,

    I am not sure if my understanding is correctly. Please do correct me if I miss something.

    • You are able to see EVM are able to link up with external switch when auto-negotiation is on
    • You are not able to establish a link with EVM with external switch when auto-negotiation is off

    If my understanding is correct. Could you try the following test

    • When you disable the auto-negotiation on EVM, could you able to link up with another EVM?
    • May I ask what peak to peak voltage does external switch support? 1V p2p or 2.4Vp2p?

    --

    Regards,

    Hillman Lin

  • 0 in reply to Hillman Lin
    Prodigy 20 points

    Hello,

    thank you for your feedback...

    Your understanding is right. We are going to test if we are able to link up with another EVM with auto-negotiation disabled - I will provide feedback once we have the results.

    Our external switch supports both 1V and 2.4V. But only 1V level should be accepted for communication by our EVM. It means that if 2.4V is requested by external switch, EVM shall not link up with it.

    Kind regards,

    Petr Sulima

  • 0 in reply to Petr Sulima
    TI__Mastermind 25955 points

    Hi Sulima,

    Have you try the following script when you are enable the auto-negotiation?

    • Fullscreen 2.4V work with link up (working).txt Download 
      begin
//000D 0007
//000E 0200
//000D 4007
//000E 0000 //disable auto neg

000D 0001
000E 08F6
000D 4001
000E 1000 //enable 2.4 Vpp operating mode

000D 0007
000E 020E
000D 4007
000E B000 //request increase transmit level

000D 001F
000E 0010
000D 401F
000E 4000 //soft reset

//000D 0007
//000E 0200
//000D 4007
//000E 1000 //enable auto neg
end

    --

    Regards,

    Hillman Lin

  • 0 in reply to Hillman Lin
    Prodigy 20 points

    Hello,

    we found out that we incorrectly set PMA_CTRL register resulting in incorrect PHY behavior.

    We are now able to link-up while AN is disabled. However we can observe, that in case the link partner is transmitting in 2.4V level we can link-up and communicate while transmitting in 1V level (we are not quite sure if this is a problem or not). Is there any way how to disable the communication and link-up with link partner transmitting in 2.4V level while AN is disabled? Is it necessary to set TDR_CFG1register bit 12 (cfg_tdr_tx_type)? Or is TDR_CFG1 register not relevant in this case (because we observed that setting TDR_CFG1 register does not have any effect to this behavior)?

     For situations where AN is enabled we do not have such issue, because we are checking the AN_STATUS_10BT1 bit 12 and in case link partner is advertising 2.4V level we are forcing slave mode and restarting AN (AN_CONTROL: mr_restart_an = 1) so we do not link-up nor communicate with such link partner.

     Thank you in advance for a feedback.

  • 0 in reply to Petr Sulima
    TI__Mastermind 25955 points

    Hi Sulima,

    Thank you for the information.

    Just want to confirm on my understanding. Currently, the link partner PHY is not able to support the auto-negotiation between 1V p2p and 2V p2p. Customer currently would like to check if 510 is able to support auto-negotiation even when the link partner does not support auto-negotiation?

     

    If my understanding is correct, DP83TD510E could only successfully auto-negotiation when the link partner also support auto-negotiation feature. We would recommend customer to force to corresponding peak to peak voltage as link partner for the correct link up process.

    --

    Thank you,

    Hillman Lin

  • 0 in reply to Hillman Lin
    Prodigy 20 points

    Hello,

    we tested our EVM (1V) with auto-negotiation disabled with another EVM with auto-negotiation disabled where we changed the transmit level to 2.4V to see if our EVM will link up. Our expectation was that link up won't be possible (since our EVM is 1V only), but the link up was successful and our EVM communicates on 1V level.

    So the question was, if this is correct behavior? Is there any mechanism how to disable the communication when AN is disabled and link partner is transmitting in 2.4V level?

    Case where link partner does support AN is clear.

  • 0 in reply to Petr Sulima
    TI__Mastermind 25955 points

    Hi Sulima,

    We will take a look and get back to you later this week.

    --

    Regards,

    Hillman Lin

  • 0 in reply to Hillman Lin
    TI__Mastermind 25955 points

    Hi Sulima,

    May I ask which EVM is configure as master and which EVM is configure as slave?

    --

    Regards,

    Hillman Lin

  • 0 in reply to Hillman Lin
    Prodigy 20 points

    Hello,

    our test EVM (1V) was configured as slave and second EVM (2.4V) as master.

    Thank you for your feedback.

    Kind regards,

    Petr Sulima

  • 0 in reply to Petr Sulima
    TI__Mastermind 25955 points

    Hi Sulima,

    Thank you for sharing the observation. It is interesting that DP83TD510 could link up when the auto-negotiation is disable on one of the PHY. If both side auto-negotiation is turn on, the PHY will link up in highest possible speed. if one EVM is 1V and link partner side could support both 1V/2.4V, the PHY will link up in 1V.

    If one of the DP83TD510 support only 1V (auto-neg disable) and other side support both 1V/2.4V. The PHY will read back the voltage level response by the slave and configure the correct peak to peak voltage level. This observation is expected. 

    --

    Regards,

    Hillman Lin