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HD3SS3212-Q1: HD3SS3212RKSTQ1 without CC controller

Nikunj Zadeshwariya
Prodigy 175 points
Part Number: HD3SS3212-Q1

Tool/software:

Hi,

I am using HD3SS3212RKSTQ1 for my application (USB type C 3.1 interface as sink only device). As I only require Communication over USB without any power from USB, can I exclude use of CC/PD controller? 

I see that the Mux SEL pin requires Input from controller which eventually controls the ports. Is there any alternate design/components which can avoid use of controller ? or can I simply keep pull up/down the SEL pin?

 

Thanks,

Nikunj

  • 0
    TI__Genius 17685 points

    Hello Nikunj,

    Yes, you can use pull downs/ups on the select pins. 
    A controller is not required.

    Thanks,

    Nir 

  • 0 in reply to Nir Gilgur
    Prodigy 175 points

    Hello Nir,

    Thanks for your inputs. I have another query on the same.

    By pulling up/down, my device will always connect one of the port (B or C) to Port A in HD3SS3212-Q1.

    Lets say if I keep SEL pin pulled low by hardware resistor, Tx/Rx-1 pair of Type-C (which connects to the PC in my application) will always be connected to port A .

    Does this configuration has any challenges or limitations? I need to understand if there are any foreseen risk associated if any.

    Thanks,

    Nikunj

  • 0 in reply to Nikunj Zadeshwariya
    TI__Genius 17685 points

    Hello Nikunj,

    If you keep the OE pulled down, while maintaining a high, or low constant pull on the SEL you will maintain a connection on the A pin. 
    From the mux perspective this is not an issue as long as the signals being passed are within the specification limits. 

    Thanks,
    Nir 

  • 0 in reply to Nir Gilgur
    Prodigy 175 points

    Hi Nir,

    So using SEL as pulled high/low, I will be using only one port B or C of Mux. 

    It brings me to the following queries:

    1) Without CC controller what should be the CC pins configuration on type-C connector? Should I connect CC1 and CC2 pulled low with 5.1k resistor? Please note that I am not using the USB power for my application. It is self powered by external adapter.

    2) Is it not possible to avoid Mux itself and connect directly one pair of SS lines of USB type-C directly to the processor? I know that Type-C flip functionality will be affected, but need to understand how does mux implementation will differ (with SEL pulled high/low by resistor) from this approach.

    Thanks,

    Nikunj

  • 0 in reply to Nikunj Zadeshwariya
    TI__Genius 17685 points

    Hello Nimunj,

    My initial understanding was the controller won't be used on the logic pins, but will for the CC ones.
    Let me come back to you on this, I need to check the footprint of the device with the designer.

    What is the application here? What is the mux use case? 
    Please provide more details. 

    Thanks,

    Nir 

  • 0 in reply to Nir Gilgur
    Prodigy 175 points

    Hi Nir,

    Below is my use case:

    • I need to connect USB type-C connector with USB3.1 interface and do not need power from USB type-c as my device gets powered from adapter.
    • To interface the Type-C connector and use flip functionality, I am using Mux. 

    I am need to understand what will be a challenged in below scenario:

    1. without CC-controller and with Mux
    2. Without CC-controller and without Mux (One of the SS lines of type-C will directly connect to USB3.1 interface)

    Shared reference block diagram image below.

    Thanks,

    Nikunj

  • 0 in reply to Nikunj Zadeshwariya
    TI__Genius 17685 points

    Hello Nikunj,

    Thank you for the elaboration, I am still waiting on a response from the design engineer.

    I am a MUX expert, not a USB one, but I think there will be no issues if you connect directly the SS lines to the interface. 

    As I said I am still waiting on a confirmation from the designer if the mux can be used without a CC controller.
    I will relay their response as soon as I receive it.

    Thanks,

    Nir 

  • 0 in reply to Nir Gilgur
    TI__Genius 17685 points

    Hello Nikunj,

    Without the CC controller the flip feature wont be detected. 
    The Mux's SEL input is driven by the CC-Controller after it determines the cable orientation. Without a CC-Controller, you have no automatic way to determine this.

    If the Mux is not switched correctly, your USB 3.1 SuperSpeed connection will fail 50% of the time (whenever the cable is flipped from the "correct" hardwired orientation).

    Also, for your second case by directly connecting only one set of SS lanes, your USB-C port will only work if the cable is inserted in one specific orientation. If flipped, the SuperSpeed connection will fail 100% of the time for that orientation.

    Thanks,

    Nir 

  • 0 in reply to Nir Gilgur
    Prodigy 175 points

    Thank you Nir for sharing the details and confirmation.

    can you please share the reference design suitable with my application along with CC controller?

    Thanks,

    Nikunj

  • 0 in reply to Nikunj Zadeshwariya
    TI__Genius 17685 points

    Hello Nikunj,

    I am not sure if we have reference design similar to your application, but you can find them under the product page in the Reference designs section. 

    Here is the reference design for the HD3SS3212-Q1.

    Thanks,

    Nir