串行端口的本质功能是作为CPU和串行设备间的编码转换器。当数据从 CPU经过串行端口发送出去时，字节数据转换为串行的位。在接收数据时，串行的位被转换为字节数据-The nature of the serial port function as CPU and serial devices encoding converter. When the data from the CPU through a serial port to send out, the byte data into a se