说明：  本节所给出主程序功能为51单片机从USB总线读取两个字节数据，计算两个数据的和。另外本文还给出了CH372的主端点、辅助端点之间数据上传下传的子程序
(This section gives the main program functions from the USB bus, microcomputer 51 reads the two bytes of data, both data and calculations. Another article also gives the CH372 main endpoint, secondary endpoint data upload downlink between the subroutine)