5 Replies Latest reply on Oct 14, 2019 9:37 PM by RajathB_01

    CYPD3174 PD Controlled - USB2 lanes

    GiDv_4443416

      Using the CYPD3174 with a USB component (ASM3142 - PCIe-USB bridge), I wondered how to connect and layout the two USB2 lanes (DP0, DM0, DP1, DM1).

      From the type C connector, those lanes should be connected both to the PD controller and to the USB component, so a stub looks unavoidable.

      How would you offer to connect and layout those lanes?

      Thanks!

        • 1. Re: CYPD3174 PD Controlled - USB2 lanes
          RajathB_01

          Hello,

           

          1) CCG3PA is not recommended for data applications. It cannot support Data Role swap or datapath mux control and related features.

          2) DP0, DM0, DP1 & DM1 are High-Speed lines and therefore can be shorted into DP, DM. Stub can be tolerated.

          3) DP, DM connects to both PD controller and USB-PCIe bridge - do you plan to use a high-speed mux for this purpose? Please note that DP, DM connection to PD controller will only be for two reasons - (a) Battery Charging protocol detection, (b) Alternate mode billboard interface.

          4) CYPD3174 does not support option (b) in above point. That is supported by CCG3 only. If you are looking for option (a) then please use a mux for the high-speed path to switch between PD and USB-PCIe Bridge.

           

          Regards,

          Rajath

          • 2. Re: CYPD3174 PD Controlled - USB2 lanes
            GiDv_4443416

            Hi Rajath,

             

            1, 2 - I see in the CCG3PA datasheet that CYPD3171-24LQXQ does support DRP. Can you please clarify?

            In addition, In my design, the power direction is fixed (PD only). I guess it may solve that problem?

            3 – My application combines high speed data with PD to the target device. Shouldn’t I connect DP, DM to the PD controller?

            4 – Can you please explain why is a mux needed, as I want those lines to both PD controller and USB-PCIe bridge?

             

            Thanks,

            Gilad

            • 3. Re: CYPD3174 PD Controlled - USB2 lanes
              RajathB_01

              Hi Gilad,

               

              1,2) The DRP datasheet is referring to is 'power' role (provider/consumer) and not 'data' role (host/device).

               

              3) The CCG3PA PD controller does not have a USB 2.0 Physical layer. Hence it is not possible for the PD controller to communicate on the USB2. The DP, DM pins on CCG3PA are only for legacy charger detect (termination presenting and detection). See the following description from datasheet:

              " The two charger detection blocks connected to the two pairs of

              DP/DM pins allow CCG3PA to detect conventional battery

              chargers conforming to BC 1.2, and the following proprietary

              charger specifications: Apple, Qualcomm’s QuickCharge 4.0,

              and Samsung AFC."  - CCG3PA datasheet, page 4.

               

              4) USB spec allows connection of two devices to one host only through either a hub or a multiplexer. But as in (3), if you are not doing legacy charging, you can ignore my 4th point and connect USB2 lines to your bridge controller only.

               

              Regards,

              Rajath

              • 4. Re: CYPD3174 PD Controlled - USB2 lanes
                GiDv_4443416

                Hi Rajath,

                Thanks for your explains.

                I’m indeed not doing legacy charging, but still need the PD for supplying the USB devise that will be connected to my application.

                 

                  1.  Will connecting USB2 lines to my bridge controller only harm that functionality?

                  2.  What did you mean by writing that CCG3PA cannot support Data Role swap – Will CCG3PA support that switch (without power role switch) or it is also unsupported?

                Thanks,

                Gilad

                • 5. Re: CYPD3174 PD Controlled - USB2 lanes
                  RajathB_01

                  Hi Gilad,

                   

                  1.  Will connecting USB2 lines to my bridge controller only harm that functionality?

                  >> No. PD is unrelated to USB2.0 lines. PD negotiation will only require CC lines and VBUS.

                   

                  2.  What did you mean by writing that CCG3PA cannot support Data Role swap – Will CCG3PA support that switch (without power role switch) or it is also unsupported?

                  >> It supports Power Role Swap, but does not support Data Role Swap. This means the host you are connecting to should always assume itself as host and your CCG3PA as device. This should be fine if you are connecting your device to a host PC or notebook. If you plan to connect to a tablet or any host that has OTG mode, you will sometimes require Data Role Swap as the host might assume itself as device (depending on VBUS direction). Anyway, if you are not using OTG hosts in your applications (and opposite directions of power and data), CCG3PA should work fine.

                   

                  Regards,

                  Rajath