十一、串行通信和8251A在很多应用场合,微型计算机同I/O中设备(输入、输出设备)之间的数据交换是以串行通信方式进行的,即用一条线发送,用另一条线接收.被传送的每个数字化信息位是一个接一个地发送或接收的.串行通信有同步和异步之分.发送或接收一个字符的时间间隔如果是不变的,称为同步通信;如果字符间隔时间是变化的,则称为异步通信. Serial Communications and the 8251A In many applications, the exchange of data between microcomputers and I / O devices (input and output devices) is done by serial communication, sending in one line and using the other Line reception. Each digitized information bit to be transmitted is sent or received one after another. Serial communication has the distinction between synchronization and asynchronism. The time interval for sending or receiving a character, if it is constant, is called synchronous communication; If the character interval is changing, then known as asynchronous communication.