1，将STM32的USB枚举为HID设备。
2，STM32使用3个端点，端点0用于枚举用，端点1和2用于数据的发送和接收。
3，端点长度为64，也就是单次最多可以传输64个字节数据。
4，STM32获取上位机下发的数据并将该数据通过USB原样返回，同时将数据打印输出。
5，上位机程序通过调用windows的API实现对HID设备的读写控制。(1, the STM32's USB is enumerated as a HID device.

2, STM32 uses 3 endpoints, the endpoint 0 is used for enumeration, and the endpoints 1 and 2 are used for sending and receiving data.

3, the endpoint length is 64, that is to say, a single pass can transmit 64 byte data at most.

4, STM32 gets the data sent by the host computer and returns the data through the original USB, and prints and outputs the data at the same time.

5, the upper computer program realizes the read and write control of HID device by calling the API of windows.)