1 Reply Latest reply on Apr 17, 2019 8:08 PM by YiZ_31

    CCG4 Evaluation Board Problem - Breaking UFP/DFP Data and PD roles


      I have a unique-ish proof of concept I'd like to demonstrate with the CCG4 Evaluation kit but

      I have had no luck with EZ-PD configuration utility.


      I would like to attach a self-powered peripheral to J2 of the eval board and a USB-C connected

      tablet to the USB-C connector J3.  I would like the eval board to provide power to the tablet (serve

      as DFP PD role) but at the same time, allow the tablet to serve as USB host so that it can detect the

      peripheral on J2 (serve as DFP data role).


      As of now, I can only do one or the other:

      1) With the eval board providing power, the tablet charges as expected but does not enumerate my peripheral on J2.

      2) With the tablet powering the eval board, it successfully enumerates the peripheral on J2.


      How can I achieve this using EZ-PD configuration Utility? I've played around with several settings (ie, making the eval

      board a SOURCE only) but that has not worked.


      Do I have to alter the firmware to achieve this? Where would I begin?

        • 1. Re: CCG4 Evaluation Board Problem - Breaking UFP/DFP Data and PD roles



          First thing to clarify: J2 is not recommended to connected to a device because the MUX in CY4541 is a one-way MUX. The USB 3.0 data lane will not work this way. Your device could enumerate because the USB 2.0 data lane is directly connected from J2 to Type-C port.


          Here is my guess for the reason of this problem: According to Type-C spec, the role that a dual-role-data port initially takes is determined by the port’s power role at attach. After attached, CCG4 takes your device as data and power sink, and your tablet also accept its role as data sink without negotiating a DR_Swap. Then the contract is established.


          If you really want to achieve this, modifying configuration table is not enough. You will force the CCG4 to negotiate a DR_Swap after the power role is set. That need modifying source code of CCG4 firmware.