基于Z85C30实现USB转双通道同异步串口的源码，本程序采用环形缓冲，多中断等方法实现了串口数据和USB数据的交换，由于单片机速度限制异步只能做到100K，同步只能做到57k。-Z85C30 based USB to dual channel asynchronous serial source code, the program uses a ring buffer, multiple interrupt other methods to achieve the serial data an