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  • TI Thinks Resolved

TUSB1064: TUSB1064

Genius 3725 points

Replies: 19

Views: 377

Part Number: TUSB1064

Hi Sir,

Our customer used the TUSB1064EVM with Dell XPS15 9550, But no DP Alt mode output.

The DA400.Zip file is used DPA-400 read data, 20190103-source.bin.html is MUX side, 20190103-sink.bin.html is after MUX.

The Good NB Waveform.Zip File is used other NB waveform, But  Dell XPS15 9550 no waveform.

Could you give us a suggestion?

Hugo

DA400.zipGood NB Waveform.zip

  • In reply to Hugo Liu:

    Hugo

    This is an issue with the XP15 9550, the strong 100k pulldown on AUXP is incorrect or missing, and 100k pulldown on AUXN is incorrect or missing in XPS15, resulting in incorrect common mode voltage for TUSB1064.

    On the TUSB1064EVM, please have 100k pulldown on AUXP and 100k pullup on AUXN. What is the voltage after you do the rework and does the monitor work now?

    Thanks
    David
  • In reply to David (ASIC) Liu:

    Hi David,

    Thank for your suggest.
    How about 1M resistance, Remove it or 100k & 1M Both on EVM?

    Hugo
  • In reply to Hugo Liu:

    Hugo

    Please remove the 1M.

    Thanks

    David

  • In reply to David (ASIC) Liu:

    Hi David,

    Good news, our used the 100k pulldown on AUXP and 100k pullup on AUXN.
    The function is ok, but the TI Datasheet is show the 1M resistance value,
    If our customer change to 100k , then any rick?
    Do you have document to Description 100k?

    AUXP=2.5V
    AUXN=0.5V

    Hugo
  • In reply to Hugo Liu:

    Hugo

    Below is an AUX channel block diagram.

    On the AUXP, we have 100k pulldown on the source side and 1M pullup on the sink side, results in ~0.3V common mode voltage on AUXP. 

    On the AUXN, we have 100k pullup on the source side and 1M pulldown on the sink side, results in ~3V common mode voltage on AUXN.

    The 1M resistor in TUSB1064 assumes we are dealing with a DP compliant source.

    Looking at the previous common mode voltage measurement results, it looks like we are dealing with a non-compliant DP source . The 100k pullup/pulldown on the source side is missing or populated with resistor weaker than 1M resistor. 

    By adding 100k on AUXP/AUX on TUSB1064, we basically make the 100k resistors to be the strong resistor when comparing against 1M resistor, therefore correctly set the common mode voltage for both AUXP and AUXN.

    On a compliant DP system, we would have two 100k pulldown/pullup, the two combined 100k pulldown (50k) would still be strong when comparing against 1M resistor. AUXP common mode voltage would be around ~0.157V and AUX common mode voltage would be around ~3.143V, still within AUXP/N common mode spec requirement. It looks the latest measurement is backward, would you please check again?

    Again, the 100k is a workaround solution for non-DP compliant system. The fix needs to be on the source side to make it to be compliant.

    Thanks

    David

  • In reply to David (ASIC) Liu:

    Hi David,

    The TI TUSB1064EVM only have TYPE C & DP connector,
    How to verify non-DP compliant system?

    Hugo
  • In reply to Hugo Liu:

    Hugo

    What other interface do they plan to use?

    Thanks
    David
  • In reply to David (ASIC) Liu:

    Hi David,

    Our customer this design is the TYPE C to DP Docking.

    Hugo
  • In reply to Hugo Liu:

    Hugo

    Would you please provide more detail on the customer's implementation? Are they looking to connect non-DP compliant to the dock? I am trying to understand what they to accomplish here.

    Thanks
    David

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