Embedded-system applications use WDTs (watchdog timers) to identify error conditions that cause the controller or processor to default into an erroneous state. Stand-alone WDTs used to be quite popular. For a short time, they were more reliable than their counterpart, which was the internal WDT in the controller or processor. With the controller or processor option, if the processor failed to execute in a timely manner, the WDT would surely have problems, as well. But, the stand-alone WDT fell short with its lack of an adjustable clock—allowing the user to change the setting of this timer independently of the system clock. The stand-alone WDT was missing features, such as minimum and maximum trigger times. With multiple triggers built into the WDT, you can catch situations in which the application system is running too slow or too fast.
展开▼
