3 Replies Latest reply on May 8, 2019 10:41 PM by MuthuM_11

    cascading HX3PDs to get greater-than-3 Gen2 TypeC DFP

    atmuc_4221866

      Hello there,

       

      I would like to understand the feasibility of using multiple HX3PDs to create a hub with more than three 10Gbps TypeC ports on a single host.

       

      Let's start with the reference design -- a single HX3PD with the following DS ports:

      - 1x 3.1-Gen2-TypeC-PD3.0 (DS1)

      - 2x 3.1-Gen2-TypeC-noPD (DS2, DS3)

      - 2x 3.1-Gen2-TypeA (DS4, DS5)

      - 2x 2.0-TypeA (ignore these)

      So in this single-board HX3PD#1 configuration, I have 3 TypeC DFP ports (DS1-DS3).

      Is this correct so far?

       

      Now, let's say I have two of these reference design boards (HX3PD#1, HX3PD#2).

      How can I wire the two boards together to achieve the most TypeC ports?

      Here are a few scenarios I can think of:

      1) Can I connect HX3PD#2-US port to either HX3PD#1-DS4 or -DS5 and still have full TypeC bandwidth on each port on HX3PD#2?

      ----> Result: 6x TypeC ports -- HX3PD#1 DS1/DS2/DS3, HX3PD#2 DS1/DS2/DS3, 2 of which are PD-capable.

      2) Furthermore, can I reconfigure the firmware to move HX3PD#2 Upstream port to be on one of the TypeA ports (DS4,DS5), therefore freeing up HX3PD#2-US port as a DFP-PD port?

      ----> Result: 7x TypeC ports -- HX3PD#1 DS1/DS2/DS3, HX3PD#2 US/DS1/DS2/DS3, 3 of which are PD-capable.

      3) Or, do I NEED to connect TypeC-to-TypeC?

      ----> Result: 5x TypeC ports -- HX3PD#1 DS1/DS3, HX3PD#2 DS1/DS2/DS3, 2 of which are PD-capable.

      4) Or even worse, do I need to connect TypeC-PD-to-TypeC-PD?

      ----> Result: 5x TypeC ports -- HX3PD#1 DS2/DS3, HX3PD#2 DS1/DS2/DS3, only 1 of which is PD-capable.

       

      Are there any other configurations that make more sense?

      Any thoughts are greatly appreciated.

       

      Thanks in advance,

      -- Atsushi

        • 1. Re: cascading HX3PDs to get greater-than-3 Gen2 TypeC DFP
          MuthuM_11

          Hi Atsushi,

           

          We can have one more option with single HX3PD by adding a dual port PD controller (CCG4 or CCG5) & USB 3.1 Gen2 MUX:

          Add a dual port PD controller (CCG4 or CCG5) & 2x USB 3.1 Gen2 MUX (10 Gbps) per port at DS4& DS5 to make DS4 & DS5 as Type-C/PD supported.

          So, the result would be:

          - 1x 3.1-Gen2-TypeC-PD3.0 (DS1)

          - 2x 3.1-Gen2-TypeC-noPD (DS2, DS3)

          - 2x 3.1-Gen2-TypeC-PD3.0 (DS4, DS5) -- with 2x external USB 3.1 Gen2 MUX & 1x CCG4/CCG5

           

          On the design with 2x HX3PD's, the optimal solution would be:

          - Connect HX3PD-2's US port to HX3PD-1's DS4 or DS5. We can reassign the US PD controller to control one of the Type-C only port (DS-2 or DS-3) or Type-A port with external USB 3.1 Gen2 MUX (DS-4 & DS-5)

          So, the result would be either of the following:

          HX3PD-1:

          - 1x 3.1-Gen2-TypeC-PD3.0 (DS1)

          - 2x 3.1-Gen2-TypeC-noPD (DS2, DS3)

          HX3PD-2:

          - 2x 3.1-Gen2-TypeC-PD3.0 (DS1, DS2)

          - 1x 3.1-Gen2-TypeC-noPD (DS3)

           

          [OR]

           

          HX3PD-1:

          - 1x 3.1-Gen2-TypeC-PD3.0 (DS1)

          - 2x 3.1-Gen2-TypeC-noPD (DS2, DS3)

          HX3PD-2:

          - 1x 3.1-Gen2-TypeC-PD3.0 (DS1)

          - 2x 3.1-Gen2-TypeC-noPD (DS2, DS3)

          - 1x 3.1-Gen2-TypeC-PD3.0 (DS4) with external USB 3.1 Gen2 MUX

           

          Note that one the HX3PD reference design boards, we cannot detach HX3PD-2's PD controller from US port and assign to another port.

           

          Regards,

          Muthu

          • 2. Re: cascading HX3PDs to get greater-than-3 Gen2 TypeC DFP
            atmuc_4221866

            Hello Muthu,

             

             

            Thank you for your response.

            Can you provide some feedback as to whether the following block diagram is

            feasible, and if not, what you would suggest.

             

            Do you have any specific 3.1 Gen2 MUX recommendations?

             

             

             

             

             

             

            I was a little confused about your two comments:

            "We can reassign the US PD controller to control one of the Type-C only port

            (DS-2 or DS-3) or Type-A port with external USB 3.1 Gen2 MUX (DS-4 & DS-5)"

            "Note that one the HX3PD reference design boards, we cannot detach HX3PD-2's

            PD controller from US port and assign to another port."

            Does this mean that only the reference design is limited in PD controller

            configuration, but if we design a custom PCB then we can move around the US

            PD controller?

             

            What is involved in reconfiguring the US PD controller location?

             

             

            Thanks again!

             

             

            Regards,

            -- Atsushi

            • 3. Re: cascading HX3PDs to get greater-than-3 Gen2 TypeC DFP
              MuthuM_11

              Hi Atsushi,

               

              Your block diagram looks good except it does not require USB 3.1 Gen2 mux for HX3PD#2's US port. You shall connect SS lines to SS Tx1/Rx1 pair of HX3PD#2.

              usbhub_muth.jpg

               

              Yes, with custom PCB, US PD controller can be made to control DS port. Port 0 PD controller controls US port & Port 1 PD controller controls DS1 port in reference design. Reconfiguring the US PD controller to DS involves custom FW.

               

              Regards,

              Muthu