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TPS65987D: TPS65987D DRP and DRP connection

Koji Ikeda
Expert 5905 points
Part Number: TPS65987D
Other Parts Discussed in Thread: TPS65987

Hello Support team,

I receive some questions from customer.

*If TPS65987D DRP port connects to another TPS65987D DRP port each other, how each TPS65987D behave? Do you have any application note?

*TPS65987D looks to have function to set priority sink or source. If TPS65987D have it, which register bit can achieve it?

Thanks,

Koji Ikeda 

  • 0
    TI__Genius 12700 points

    Hi Koji,

    If they are both connected to each other's ports, one will be the source and one will be the sink. On the TPS65987D datasheet, there is a DRP section that states that the TPS65987D alternates the port's C_CCn pins between the pull-down resistance, Rd, and pull-up current source, Rp.

    Thank you,

    Hari

  • 0 in reply to Hari Patel1
    TI__Expert 5905 points

    Hari-san,

    Thank you for your support. Which page on dathseet is DRP section? 8.3.4.3? This is very short explanation, it is not clear how TPS65987D behave. How USB PD system decide DRP sink and DRP source?

    Thanks,

    Koji ikeda

  • 0 in reply to Koji Ikeda
    TI__Genius 12700 points

    Hi Koji-san,

    Yes that is the section I was referencing in the datasheet. However, if you would like more in depth specifications about the DRP to DRP behavior, you can read the section 4.5.3.1.4 in the USB Type-C Specification document release 1.4. This document shows 3 different cases and the process the DRP ports go through to decide which will be sink and source. 

    USB Type-C Specification: https://www.usb.org/document-library/usb-type-ctm-cable-and-connector-specification-revision-14-march-29-2019

    Thank you,

    Hari

  • 0 in reply to Hari Patel1
    TI__Expert 5905 points

    Hello Hari-san,

    Thank you very much for your support.

    You mean that this would be supported by try.SNK and try.SRC. Can TPS65987 support try.SNK and try.SRC? Is GUI 0x28 for this?

    Thanks,

    Koji Ikeda

  • 0 in reply to Koji Ikeda
    TI__Genius 12700 points

    Hi Koji-san,

    Yes, the try.src and try.snk can be used by each of the TPS65987D devices and yes it is register 0x28 to configure it.

    If one device is set to try.src then if the other device is set to try.snk then they will both be configured in a correct way. However, they both cannot be set to have the same setting, only one can be source and one can be sink.

    Thank you,

    Hari