看门狗定时器（WDT，Watch Dog Timer）是单片机的一个组成部分，它实际上是一个计数器，一般给看门狗一个大数，程序开始运行后看门狗开始倒计数。如果程序运行正常，过一段时间CPU应发出指令让看门狗，重新开始倒计数。如果看门狗减到0就认为程序没有正常工作，强制整个系统复位。(The watchdog timer (WDT, Watch Dog Timer) is a component of the single chip computer. It is actually a counter, usually a large number of watchdogs, and the watchdog starts counting down after the program starts to run. If the program is running normally, CPU should issue an instruction to let the watchdog start counting again. If the watchdog is reduced to 0, it is considered that the program is not working properly, forcing the entire system to reset.)