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TUSB422: Request increasing/decreasing VBUS from exist voltage

chentsu chung
Mastermind 6180 points

Part Number: TUSB422

Hi Sir,

I know TUSB422 could record VBUS voltage in register for MCU to read, but...

1. Now using TUSB422 as DFP device and provide 5V already, if UFP want to get highier VBUS like 12V, is it passible UFP could communicate with DFP through TUSB422 and the MCU of DFP get the request from TUSB422's registor?

2.Now using TUSB422 as UFP device and get provided 5V already, if want to request gighier VBUS like 12V, is it passible MCU could write data through I2C in the register of TUSB422, and let TUSB422 communicate with DFP device by CC pin?

Thank you very much.

C.T.

  • 0
    TI__Mastermind 36085 points

    Hello Chentsu,

         First of all, both ports (DFP and UFP) must support power delivery, as well as the cable that you are using to connect both ports. The steps below are a short summary of a PD negotiation, the TUSB422 supports Power delivery and is fully capable to perform the negotiation for both cases that you've mentioned.

    1. DFP detects a valid connection to a UFP.
    2. DFP enables VBUS @5V and VCONN if needed.
    3. DFP requests the cable's capabilities (whether it supports higher VBUS and current ratings).
    4. DFP creates a list of supported power capabilities, based on the union of the cable's capabilities and its own.
    5. UFP acknowledges the capabilities and requests the desired power profile from the available options (transmitted previously by DFP).
    6. If the power profile is valid, then the DFP accepts the request and enables the selected power profile

    DFP periodically transmits its valid capabilities, so the UFP can request a different profile later.

    For a deeper understanding of this process, as well as more information regarding the power role swaps and changes on the PD contracts please refer to the Power delivery specification, available on the USB.org site here.

    Best regards,

    Diego.

  • 0 in reply to Diego Cortes
    Mastermind 6180 points
    Hi Diego,

    Thanks for your explanation. So TUSB422 must have register for power profile configuration, but I can't fine any registor about PD voltage level(5V/12V/20V...) or current, could you kindly help me to find it? thank you.

    Best regards,

    C.T.
  • 0 in reply to chentsu chung
    TI__Mastermind 36085 points

    Hi CT,

       The TUSB422 is only a Type-C Port Controller (TCPC), it is only the physical layer of Power Delivery  and changing VBUS is not that simple (you have to define a PD profile for the 12 volts that you want to support). It is mandatory to implement all the PD protocol in a uC that will act as Port manager, controlling the TUSB422. Please request the example code here.

    Best regards,

    Diego.