Watchdog chip Watchdog working principle
In the microcomputer, because the single-chip microcomputer is often interfered with by the external electromagnetic field, the register and memory data are confused, which causes the program pointer error to fall into an infinite loop, and the microcomputer system cannot work normally. At this time, a watchdog is needed to solve the problem.
The watchdog, named watchdog, is a monitoring chip based on a timer circuit that can be used to automatically detect software abnormalities and reset the processor in case of any abnormality. There is usually one input and one output. The input is called a feeder, and the output is connected to the reset terminal of another part, usually a single-chip microcomputer. The watchdog is mainly used to check the internal situation of the chip regularly. Once the computer system has an error or failure, it will send a restart signal to the chip. The watchdog has the highest priority in program interruption.
The basic principle of the watchdog chip is as follows:
Watchdog is a monitoring system, through the combination of software and hardware, to realize the monitoring of the operating status of the computer system. The stable running software will feed the dog after executing the specific instruction. If the dog feed signal from the software is not received within a certain period, it will be considered that the computer system is malfunctioning and will enter the interrupt processing program or force the program to reset.
The main purpose of feeding the dog is to reset and restart to ensure the normal operation of the computer system.
The watchdog is mainly composed of registers, accelerators, and barking modules. The basic operation settings of the watchdog are carried out through the registers. The counter sets the barking time, and the barking module will determine the interrupt or reset mode sent out after the watchdog times out.
Watchdogs are mainly classified into hardware watchdogs and software watchdogs.
The hardware watchdog monitors the main program running through a timer.
Software watchdog is to design a software watchdog through idle timer/counter.