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DP83TC811R-Q1: SQI and PMA issues

Cherry Zhou
Mastermind 22235 points
Part Number: DP83TC811R-Q1
Other Parts Discussed in Thread: DP83TC811

Hi team,

Here's an issue from the customer may need your help:

1) During the tc8 test, the signal generator was used to keep noise increasing to decrease the SQI value. After the noise was increased to a certain value, the PHY state did not change to link down. Why's this? 

2) When master switches to slave, a problem has been observed with the loss value of the mode transition. What typically affects losses? Is it possible to change the value by modifying the software configuration?

3) The return loss values were also found to be problematic when doing the return test, what was the impact on the return loss values? Is it possible to change the value by modifying the software configuration?

4) When switching to testmode 4, the transmitter distortion = 20 mV. Is there any other way to configure the values besides setting the mode?

Could you help check this case? Thanks.

Best Regards,

Cherry

  • 0
    TI__Mastermind 20766 points

    Hi Cherry,

    1. How much noise did you add, and what was the respective SQI reading? Why are you expecting link to drop? The communication will have some immunity to noise. 

    2. What do you mean by "a problem has been observed with the loss value of the mode transition"?

    3. Please share the procedure used to conduct this test. Share any images or reports you have. What was the state of the device when performing this test?

    4. Please share the complete report of all PMA compliance tests conducted.

    Thanks,

    David

  • 0 in reply to David Creger
    TI__Genius 10295 points

    Hi David,

    1. SQI values are monotonically decreasing. Because tc8 hopes to reduce SQI by adding noise. When the noise reaches a limit, the link state changes to linkdown. Does dp83tc811 support this processing?

    2. The following is the test process

    return loss

    Initial conditions:

    power mode IG ON;

    Test steps:

    step1: Set the device under test as the default mode.

    Step2: Set the test device to slave mode.

    Step3: Measure the value of return loss.

    Desired result:

    step3: Between 10Mhz-600Mhz, the value of return loss is lower than the limit line.

    Actual results:

    step3: Between 14Mhz-67Mhz, the value of return loss is higher than the limit line.

    3. See attachment

    回波损耗的值高于界限线.pdf

    4. See attachment

    发射器失真值过大.pdf

    Thanks,

    Annie

  • 0 in reply to Annie Liu
    TI__Mastermind 20766 points

    Hi Annie,

    Have you seen the following app note: SNLA293

    Are you using the software configuration described here? If not, please do so and send me updated results.

    Thanks,

    David

  • 0 in reply to David Creger
    TI__Mastermind 22235 points

    Hi David,

    David Creger said:
    Have you seen the following app note: SNLA293

    Based on the app note provided, the SQI value is attenuated after noise increase. Will the link status of bit [2] in BMSR Register 0x0001 – Basic Mode Status Register be affected after the last reduction to 0x28?

    The customer does the tc8 test in the hope that the noise increase will cause BMSR Register 0x0001 – bit [2] linkdown in the Basic Mode Status Register. But for now, it seems not supported on tc811. Is the customer missing the relevant configuration?

    Thanks and regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Mastermind 20766 points

    Hi Cherry,

    Link will drop around SQI<28, yes.

    What SQI value are you reading at baseline and when adding noise?

    Thanks,

    David