说明：  1、观察喂狗与不喂狗的区别，使用PB口的LED指示灯做状态指示。 2、养看门狗的用意，在于用它监控系统：在程序本该运行的地方喂狗，如果程序卡死或跑 飞，将不会运行到那，那样狗没有被喂到，饿死了，控制器复位，得以重启从而进行控制。 3、本实验演示功能：养一只AVR内部看门狗，及时喂狗，狗不饿死，单片机不复位；不及时 喂狗，狗饿死了，单片机就复位。 4、本实验的程序设计较为简单，旨在给出养狗、喂狗，不让狗饿死的简单示例。 实际应用时考虑情况较多，要注意什么时候喂狗，放狗。
(1, observed to feed the dog and not feed the dog the difference between the LED using the PB I do a status indication. 2, the intention of raising watchdog is to monitor the system to use it: the place of the program running to feed the dog, If the program is stuck or running out, will not run to that, as the dog is not fed to starved to death controller reset, able to restart in order to be controlled. 3, the experimental demonstration of function: raising an AVR internal watchdog, in a timely manner to feed the dog, the dog does not starve to death, the MCU is not reset not in time to feed the dog, the dog starved to death, the microcontroller reset. 4, the program design of this experiment is relatively simple, designed to give a dog, feed the dog a simple example, let the dog starve to death. Practical applications to consider the situation more, pay attention to what time to feed the dog, and dogs.)