• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 2 answers
  • Subscribers 33 subscribers
  • Views 1173 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.

TPS65982: VCONN Swap support for UFP_D receptacle case

Takashi Onawa
Genius 13200 points
Part Number: TPS65982

Hi Team,

Their application basically works as UFP_U / UFP_D / Source. 
Should TPS 65982 support "Initiate VCONN Swap" in that case?

The chapter in following document seems to say that "Initiate VCONN Swap" should be supported though,  is this recognition correct?

VESA DisplayPort Alt Mode on USB Type-C Standard
5.1.2 UFP_D on a USB Type-C Receptacle

They are requiring something advice on this point, please share any information on this if you can.

Regards,

Takashi Onawa

  • 0
    TI__Mastermind 36756 points
    Hi Onawa-san,

    Is this a PD3.0 system? Since you are using the TPS65982 I assume this is only PD2.0.
    For PD2.0 it is allowed for either side of the cable to do a SOP’ messaging despite the VCONN provider. This means that the system can still query the cable to check its capabilities (ex. 5A capable).
    The short answer is no, the UFP_D receptacle does not need to initiate the VCONN Swap.

    Thank you,
    Eric
  • 0 in reply to Eric Beljaars
    TI__Genius 13200 points
    Hi Eric-san,

    OK, I understood that it doesn't need to initiate VCONN Swap in PD2.0 case.

    Let me double check just in case.
    There is also no restriction on this point with regard to the DP alt mode specification specified in "VESA Display Port Alt Mode on USB Type-C Standard", isn't there?

    Regards,
    Takashi Onwa
  • 0 in reply to Takashi Onawa
    TI__Mastermind 36756 points
    Hi Onawa-san,

    There is also no restriction with regards to the DP alt mode with regards to initiating the VCONN Swap.

    Thank you,
    Eric
  • 0 in reply to Eric Beljaars
    TI__Genius 13200 points
    Hi Eric-san,

    Sorry, I didn't understood well the reason why UFP_D receptacle does not need to initiate the VCONN Swap.

    >For PD2.0 it is allowed for either side of the cable to do a SOP’ messaging despite the VCONN provider.
    >This means that the system can still query the cable to check its capabilities (ex. 5A capable).
    >The short answer is no, the UFP_D receptacle does not need to initiate the VCONN Swap.

    1. Could you supplement a little more why "Initiate VCONN Swap" is not necessary?
    2. Conversely, under what kind of use cases should "Initiate VCONN Swap" be enabled?

    Regards,
    Takashi Onawa
  • 0 in reply to Takashi Onawa
    TI__Mastermind 36756 points
    Hi Onawa-san,

    1. Could you supplement a little more why "Initiate VCONN Swap" is not necessary?

    The specifications you were referring to in your original post are only requirements of PD3.0. In PD3.0, only the VCONN Source can send SOP' messages to the cable. In PD2.0, either side can send SOP' messages to the cable regardless of VCONN role. In your system, there is no requirement to initiate the VCONN Swap due to the PD2.0 spec not requiring it.

    2. Conversely, under what kind of use cases should "Initiate VCONN Swap" be enabled?

    If you want your device to always be the VCONN Source no matter what is connected, you can enable Initiate VCONN Swap.

    Thank you,
    Eric
  • 0 in reply to Eric Beljaars
    TI__Genius 13200 points
    Hi Eric-san,

    OK, I understood.

    Regards,
    Takashi Onawa