• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 34 subscribers
  • Views 333 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.

DP83TG720R-Q1: TDR related questions

Chuqiang Wen
Expert 5930 points
Part Number: DP83TG720R-Q1


Hi Expert,

My customer is testing the TDR function of DP83TG720R-Q1 and meet some questions. Please support on this. 

They refer to the procedure which described in this apps note. 

Procedure: 

  • DP83TG720R-Q1 as slave
  • manually open the MDI cable
  • TDR configuration: Pre-run
    • reg[0x0301] = 0xA008, reg[0x0303] = 0x0928, reg[0x0304] = 0x0004, reg[0x0405] = 0x6400
  • Start TDR
    • 0x001E[15] = 1

Result: 

  • read 0x1e=0x0003
  • read 0x030F=0x0051

Questions: 

  • Why 0x1E show TDR fail? 
  • May you kindly review the test procedure to see if any mistakes?

Below are the screenshot for register setting and read. 

Thanks! 

Ethan Wen

  • 0
    TI__Mastermind 27252 points

    Hi Ethan,

    This looks like the correct procedure. Can you help me answer a few questions:

    1. What cable length and type is the customer using?

    2. Are they loading the initialization script listed in SNLA371 prior to conducting the TDR test?

    3. Can you try the TDR test in Cable OK and Short condition? Can you try with Master instead of slave?  

    4. What connector is being used? Are there other signals toggling in the connector?

    Thanks,

    David

  • 0 in reply to David Creger
    TI__Expert 5930 points

    Hi David,

    Thanks for your suggestion, 

    As checked with customer, they tried a new board and they can run the TDR correctly right now. 

    Just one more question from my side. 

    David Creger said:
    3. Can you try the TDR test in Cable OK and Short condition? Can you try with Master instead of slave?  

    If run the TDR test in Cable OK, the 0x1E register may show TDR fail, correct? 

    Regards,

    Ethan Wen

  • 0 in reply to Chuqiang Wen
    TI__Mastermind 27252 points

    Hi Ethan,

    Good to hear. What was the issue on the previous board?

    Chuqiang Wen said:
    If run the TDR test in Cable OK, the 0x1E register may show TDR fail, correct? 

    Please try and let me know the result.

    Thanks,

    David