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TUSB1046A-DCI: USB and DP function fail with PD cmd

Kailun Liu
Expert 3103 points
Part Number: TUSB1046A-DCI

Tool/software:

Hi team, 

Customer feedback that their TUSB1046A-DCI's USB and DP function fail when it works with PD. Can you help to share what register is related with USB and DP cmd? Thanks!

  • 0
    TI__Mastermind 39375 points

    Hi,

    The following register relate to alt. mode:

    These registers have to do with USB:

    What is the issue customer is seeing?

  • 0 in reply to Vishesh Pithadiya
    TI__Mastermind 39375 points

    Hi Alan,

    Based off of the table provided in email:

    USB only (normal orientation):

    0x0A = 0001 0001

    0x10, 0x11, 0x12, 0x13 = Doesn't matter

    0x20, 0x21: Tune based on system

    0x22: leave as default

    USB only (flip orientation):

    0x0A = 0001 0101

    0x10, 0x11, 0x12, 0x13 = Doesn't matter

    0x20, 0x21: Tune based on system

    0x22: leave as default

    4-lane DP only (normal orientation):

    0x0A = 0001 0010

    0x10, 0x11 = tune based on system

    0x12 = read and chnage via AUX traffic

    0x13: leave as default

    0x20, 0x21: do not care

    0x22: leave as default

    4-lane DP only (flip orientation):

    0x0A = 0001 0110

    0x10, 0x11 = tune based on system

    0x12 = read and chnage via AUX traffic

    0x13: leave as default

    0x20, 0x21: do not care

    0x22: leave as default

    2lane DP + USB (normal orientation):

    0x0A = 0001 0011

    0x10, 0x11 = tune based on system

    0x12 = read and chnage via AUX traffic

    0x13: leave as default

    0x20, 0x21: tune based on system

    0x22: leave as default

    2lane DP + USB (flip orientation):

    0x0A = 0001 0111

    0x10, 0x11 = tune based on system

    0x12 = read and chnage via AUX traffic

    0x13: leave as default

    0x20, 0x21: tune based on system

    0x22: leave as default

  • 0 in reply to Vishesh Pithadiya
    TI__Expert 3103 points

    Hi Vishesh, 

    Thanks for your reply!

    Does the first one 0x22 is typo, means 0x0A? 

    Besides, Customer is asking how to config the EQ value in red circle, is that based on layout? 

  • 0 in reply to Kailun Liu
    TI__Mastermind 39375 points

    Hi,

    Kailun Liu said:

    Thanks for your reply!

    Does the first one 0x22 is typo, means 0x0A? 

    Yes this was a typo, I edited the original message. Good catch!

    Kailun Liu said:

    Besides, Customer is asking how to config the EQ value in red circle, is that based on layout? 

    Yes, the EQ values will be determined based off of layout. You can approximate the loss of the pre-channel and post-channel by using the constant

    0.2dB of loss/ inch/GHz.

    for example a 10Gbps (5GHz) signal will have a loss of approx. 1dB/inch. You can use this approximation to create a range of EQ values that may work. Afterwards, testing eye diagrams will determine the best EQ values to use. 

  • 0 in reply to Vishesh Pithadiya
    TI__Expert 3103 points

    Thanks Vishesh! 

    The EQ value of DP is calculated using the distance from the GPU to the Mux Redriver, right?Is it this section of XCD in the image below?

    And can you help to check below I2C setting in 4LANE DP mode? Appreciated for your support! 

  • 0 in reply to Kailun Liu
    TI__Mastermind 39375 points

    Hi,

    Kailun Liu said:

    The EQ value of DP is calculated using the distance from the GPU to the Mux Redriver, right?Is it this section of XCD in the image below?

    Yes the DPEQ values are used to compensate for the loss highlighted here.

    Kailun Liu said:

    And can you help to check below I2C setting in 4LANE DP mode? Appreciated for your support! 

    Yes this is in 4 lane DP mode for normal and flip because 0x0A is either 0x02 or 0x06

    I recommend using 0x12 and 0x16 because this will allow I2C tuning for the EQ values. Otherwise only the sampled EQ values on the pins will be used.