• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 2 answers
  • Subscribers 33 subscribers
  • Views 347 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DS160PR410: DS160PR410

Kevin Kim
Prodigy 10 points
Part Number: DS160PR410

It happens during PCIe detection stage.

AC cap is placed between RC and RX pin of DS160PR410.

I see/ don't see RX_detection ramping slope depends on different EP is connected on TX side of DS160PR410.

Is Termination on RX side of this chip dynamically controlled? or statically placed?

It seems this termination on/off depends on different EP connected.

I would like to know why it is different.

DS160PR410 rx_detection logic decides the termination on/off?

I am not able to find good explanation about termination control in the datasheet.

Any application note for this termination and rx_detection logic?

 

Thanks,

-Kevin

  • 0
    TI__Guru* 93670 points

    Hi Kevin,

    RX detection follows PCIe recommendations. 

    1). On power up, RX and TX side of a channel are high impedance.

    2). Device sends out pulses on its TX to identify if there is a termination on its output.

    3). Once this termination is detected, device turns on termination on its TX and RX side. Therefor based on the end point, there can be different timing.

    Regards,Nasser

  • 0 in reply to Nasser Mohammadi
    Prodigy 10 points

    Hi Nasser,

    I appreciate your answer.

    It sound like termination on RX side is dynamically on/off based on EP connected. (It is not always statically placed. Understood.)

    I have another question.

    As a H/W engineer, Let's assume if there is no I2C control and it already powered up without EP connected. and then EP is connected.

    Do you think if any chance this termination is not turned on?

    Thanks,

    -Kevin

  • 0 in reply to Kevin Kim
    TI__Guru* 93670 points

    Hi Kevin,

    Scenario you are mentioning is like hot plug in. In this case, PR410 keeps sending pulses forever until the EP is plugged in and it turns on its termination. Hot plug in works given the system is setup to support this.

    Regards,Nasser

  • 0 in reply to Nasser Mohammadi
    Prodigy 10 points

    Hi Nasser,

    Yes, your explanation is exactly what I've seen. I was able to see permanent seeking pulse until EP is connected. however, I always don't see RX-detection slope on RX side from RC even though the permanent seeking pulse is stopped.

    So, for now, I bypassed this re-driver by wiring jumper wire. and RX is able to detect the EP.

    I will keep in mind your explanation. I am sorry I have no time to root cause this issue.

    I appreciated your explanation.

    Thanks,

    -Kevin

  • 0 in reply to Kevin Kim
    TI__Guru* 93670 points

    Hi Kevin,

    Can you please send me scope shots showing pulses going our to when it is stopped?

    Then also show RX side of the redriver - facing root complex - ? I am thinking this can tell us what could be occuring.

    Regards,Nasser