说明：  串行接口是一种可以将接受来自CPU的并行数据字符转换为连续的串行数据流发送出去，同时可将接受的串行数据流转换为并行的数据字符供给CPU的器件。一般完成这种功能的电路，我们称为串行接口电路。
(A serial interface is a device that can convert parallel data characters a CPU to a continuous serial data stream while converting the received serial data stream into parallel data characters to the CPU. Generally complete this function of the circuit, we call the serial interface circuit.)