第 9 章:输入/输出................................................................................193 概述................................................................................................193 9.1 时间的双重角色..............................................................................194 9.2 协议..............................................................................................196 9.3 采样和轮询................................................................................198 9.4 中断................................................................................................201 9.5 传感器和执行器....................................................................................203 9.6 物理安装......................................................................................207 要点................................................................................................208 参考书目注释......................................................................................209 复习题和问题................................................................................209