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TUSB422: a few questions to consult

Chu Allen
Intellectual 790 points
Part Number: TUSB422

Tool/software:

Dear Team,

We plan to use TUSB422. Due to the USB cable having both forward and reverse connections, we have a few questions to consult:

1. How does TUSB422 identify whether a USB cable is plugged forward or reverse, based on CC1/CC2?


2. The device needs to support forward and reverse insertion and transfer USB3.0 data. Should it be equipped with a USB switch, such as FUSB340? If needed, please help recommend the model.

  • 0
    TI__Mastermind 38685 points

    Hi,

    For forward and backwards communication, the port will need to be configured as a DRP. This is possible for the TUSB422, but this will require unplugging and plugging the USB-C cable. The CC1 and CC2 lines in DRP mode will oscillate between high (5V) and low (0V) are roughly 750ns intervals. 

    A UFP will have the CC lines pulled to 0V, and wait for a DFP to be plugged in which will pull the lines up resulting in a connection. Data will flow from the DFP to the UFP.

    A DFP will have the CC lines pulled to 5V, and wait for a UFP to be plugged in which will pull the lines down resulting in a connection. Data will flow from the DFP to the UFP.

    A DRP will oscillate the lines and will be able to detect a UFP and a DFP. and configure itself (DRP) to be the opposite. Data will flow from the DFP to the UFP. 

    Changing roles will require replugging the USB-C cable. If roles are desired to be swapped without removing the connection a PD controller is required.