看门狗，眼熟的名字。无论在普通的51，还是高级的ARM。都离不开他的身影。一个完整的系统总需要一个看门狗，在你程序跑飞的时候帮你一把，使系统重新进入工作状态。它无疑是世界上最忠诚的狗。不过可千万别忘了喂它。-Watchdog, a familiar name. In terms of the normal 51, or advanced ARM. Can not be separated from his shadow. A complete system always need a watchdog to help you run your program to fly one, allowing the system to re-enter the work state. It is undoubtedly the world' s most loyal dog. But do not forget to feed it.