Controllable watchdog replacement system

Abstract

The invention relates to a controllable watchdog reset system, comprising a watchdog circuit and a microprocessor, and a system power supplying power for the watchdog circuit and the microprocessor. An isolation circuit is connected between the watchdog circuit and the microprocessor. When the system power normally supplies power, the isolation circuit transmits a reset signal of a reset pin of the watchdog circuit to a reset terminal of the microprocessor, and transmits a feeding-dog signal of I / O pin of the microprocessor to a feeding-dog pin of the watchdog circuit; when the system power is outage, the isolation circuit stops to cut off the contact between the watchdog circuit and the microprocessor. The invention has the effects of reducing system power dissipation, improving the service life of battery, and at the same time precluding a system reset problem caused by working wrongly of the watchdog circuit, and greatly improving reliability of the system.

Description

technical field [0001] The present invention relates to systems with watchdog reset circuits. Background technique [0002] At present, in some systems with a watchdog reset circuit, the commonly used method is to directly connect the watchdog reset signal and the dog feeding signal to the corresponding pins of the microprocessor (MCU), and the connection between the MCU and the watchdog circuit is not necessary. Isolated. In order to ensure that the MCU can be woken up in real time after the sleep mode or the system is shut down, when the MCU enters the sleep mode or the system is shut down, the system power supply VCC is powered off. At this time, a battery (5B in Figure 2) is usually used to power the MCU. Since the watchdog reset and dog feed signals are directly connected to the corresponding pins of the MCU, when the system power supply VCC is powered off and the MCU is powered by a battery, the battery will be directly introduced into the watchdog IC through the pins...

AI Technical Summary

Problems solved by technology

Since the watchdog reset and dog feed signals are directly connected to the corresponding pins of the MCU, when the system power supply VCC is powered off and the MCU is powered by a battery, the battery will be directly introduced into the watchdog IC through the pins of the watchdog chip, or through The inside of the MCU, the MCU pin, and the internal diode or pull-up resistor of the watchdog IC pin are connected to the system power supply VCC to supply power to the entire system circuit, resulting in increased power consumption when the system is turned off, and fast battery power consumption; and because The battery is electrically connected to the system power supply VCC, and the system power supply VCC still has a weak current to supply power to the watchdog IC, causing the MCU to enter sleep mode or the watchdog to work incorrectly after the system is shut down, causing the system to start up by mistake or the chip to be damaged.

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