What is a watchdog? Watchdog important to industrial routers?

What is a watchdog? Watchdog important to industrial routers?

　　Industrial-grade wireless router, as a very important device in wireless networking, has insight into customer application scenarios. As long as it is related to the reliability of wireless networking, even the most subtle technical applications must be extreme, such as watchdogs. Why do industrial-grade wireless routers attach so much importance to software and hardware watchdogs? Today we will take a look at the difference between software and hardware watchdogs.

Watchdog, also called watchdog timer, is a timer circuit. Generally, there is one input, called feeding dog, and one output to the RST terminal of the MCU. When the MCU is working normally, it outputs a signal to the feeding terminal at regular intervals. Clear the WDT. If the dog is not fed for more than the specified time (usually when the program is running), and the WDT timing exceeds, it will give a reset signal to the MCU to reset the MCU. Prevent the MCU from crashing. The role of the watchdog is to prevent The program has an infinite loop or the program runs away.

Working principle: After the system is running, the watchdog counter is started, and the watchdog starts to count automatically. If the watchdog is not cleared after a certain period of time, the watchdog counter will overflow and cause the watchdog. The dog is interrupted, causing the system to reset. Therefore, pay attention to the watchdog when using a chip with a watchdog.

The hardware watchdog uses a timer to monitor the operation of the main program, that is to say, during the operation of the main program, we must reset the timer before the timing is up. If there is an infinite loop, or PC pointer Can't come back. Then the microcontroller will be reset when the time is up.