3 Replies Latest reply on Jul 27, 2018 2:41 AM by RajathB_01

    do we need a switch(like PS8740B) on both the source and sink side of USB-C connector?

    roprc_3346246

      at the source side we have a tusb1046 switch/retimer and a ccg3 .

      At the sink side (a viewfinder) we only have a ccg3.

      we use display port alternate mode.

       

      our question is if we also need a switch at the sink side??

       

      thanks

       

      Ron

        • 1. Re: do we need a switch(like PS8740B) on both the source and sink side of USB-C connector?
          RajathB_01

          Hi Ron,

           

          If you require USB3.0 communication at the sink side also, you will require a switch at the sink (for example: https://www.paradetech.com/products/ps8742/ ). If you don't require USB, you can directly route the data lanes from type-C to DP sink with only CCG3 (for example refer CCG3 C-DP dongle application in CCG3 datasheet).

           

          Regards,

          Rajath

          • 2. Re: do we need a switch(like PS8740B) on both the source and sink side of USB-C connector?
            roprc_3346246

            Hello Rajath,

            Thanks for your answer.

            Its a bit confusing to me.

            The situation is as follows:

            -a broadcast camera(source) with FPGA with displayport core(transmit), TUSB1046 switch/retimer, CCG3, USB-C connector.

            -a vieffinder(sink) with USB-C connector, CCG3 and FPGA with displayport core(receive) (4 DP signal lanes directly connected to FPGA).

            We only use USB 2.0 and not USB3.0/3.1!

             

            Questions:

             

            1-Do we need a switch at the viewfinder side to control the C-type connector reversal?

            2-where can i find documentation about this C-connector reversal protocol?

            is there any handshaking about this via the CC lines or does switching happen autonomous on eac side (source--sink)?

             

            Thanks in advance.

             

            Ron Proveniers

            • 3. Re: do we need a switch(like PS8740B) on both the source and sink side of USB-C connector?
              RajathB_01

              Hi Ron,

               

              1. If you are using type-C receptacle and plug combination you will not need a switch. If you have both USB-C connectors as receptacles, connected via a type-C cable (EMCA) then you will require a switch.

               

              DP source (FPGA) <---->Switch<------> USB-C receptacle <---------------------> USB-C plug <------> DP sink (FPGA)

               

              otherwise,

               

              DP source (FPGA) <-----> Switch <-----> USB-C receptacle <---------- USB-C cable ----------> USB-C receptacle <-----> Switch <-----> DP sink (FPGA)

               

              2. CCG will detect the C-connector reversal and control the switch. If other than 4-Lane DP is used and other modes are used, it will need switch at both sides. This will be negotiated over CC lines. The connector reversal and CC orientation detect is a part of the type-C specification from USB-IF.

               

              Regards,

              Rajath