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HD3SS3212: SEL pin usaege

Part Number: HD3SS3212

Hello support team,

I would like to know about the HD3SS3212 SEL pin usage.

Two inputs for USB-type C are selected by SEL, but I will ask about how to use this SEL pin.

I am trying to switch the SEL by connecting or not connecting the CC pin of the USB cable.
On the cable side, CC1 pin is pulled up to VBUS (5 V) through 56 kΩ.
Therefore, it's pull down at 100 kΩ to connect it to the CC2 pin on the IC mounting side.

-  When CC2 pin and SEL are connected: 3.2 V divided from 5 V at 56 kΩ and 100 kΩ appears as SEL and High is recognized.

-  Conversely, when CC1 pin and SEL are connected: Low is recognized in SEL with PullDown of 100 kΩ.

As described above, I think that it is possible to switch the SEL pin High or Low by connecting 100 kΩ pull down and one side CC pin on the IC mounting side.

Could you let me know if there is any problem on this way?


Thank you and best regards,
Kaizawa

  • Kaizawa-san

    Please refer to section 4.5 of the USB Type C spec for the architecture overview of CC configuration channel.

    Functionally, the configuration channel is used to serve the following purposes.
    • Detect attach of USB ports, e.g. a Source to a Sink
    • Resolve cable orientation and twist connections to establish USB data bus routing
    • Establish data roles between two attached ports
    • Discover and configure VBUS: USB Type-C Current modes or USB Power Delivery
    • Configure VCONN
    • Discover and configure optional Alternate and Accessory modes

    I would recommend to use a dedicated CC controller to control SEL pin. The CC controller would drive SEL high or low depending on the particular condition.

    Thanks
    David
  • Hi David,

    Thanks for your answer.
    So, could you let me know your recommendation device for the CC controller?

    For HD3SS3212, does SEL pin control not work with simple high or low switching?

    Best regards,
    Kaizawa
  • Kaizawa-san

    The SEL control pin works with simple high or low switching. But CC lines are more than just detecting attach of USB ports, my concern is that toggling of CC lines will impact the SEL control pin, so the mapping from Port A to B or Port A to C can be incorrect.

    Please refer to this link for CC controller selection as it is depending on customer system requirement: .

    Thanks

    David