wenkong_junshi/Examples/USBD/composite_dev_hid_printer/readme.txt

/*!
    \file    readme.txt
    \brief   description of the the USB HID/printer composite demo

    \version 2023-06-30, V2.1.6, firmware for GD32F30x
*/

/*
    Copyright (c) 2023, GigaDevice Semiconductor Inc.

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*/

  The demo provide a composite device.

  A composite device is one that has multiple interfaces controlled independently
of each other. Using composite device, multiple functions are combined into a single
device. In this Example the independent interfaces are : custom HID and USB Printer.

  This demo was created by combining the code in the HID and USB Printer.

  The implementation of the composite HID-Printer device is done by creating a wrapping class 
(see folder hid_printer_wrapper ) that makes calls to the separate HID and USB Printer class
layer handlers (files custom_hid_core.c and printer_core.c files).

  To test the demo, you can run HID demo and at same time you can select the USB Printer.

  When even one of the interface class of the device is changed, it should be handled
differently by Windows. However, it doesn't recognize the modification. To avoid conflict
on Windows, we suggest to assign another VID/PID to the device or delete device instance 
from device manager.