CN202615379U

CN202615379U - Watchdog resetting circuit

Info

Publication number: CN202615379U
Application number: CN 201220214337
Authority: CN
Inventors: 李名星; 高发明
Original assignee: CHANGZHOU DETKIT MEASUREMENT CONTROL EQUIPMENT Co Ltd
Current assignee: CHANGZHOU DETKIT MEASUREMENT CONTROL EQUIPMENT Co Ltd
Priority date: 2012-05-14
Filing date: 2012-05-14
Publication date: 2012-12-19
Anticipated expiration: 2022-05-14

Abstract

The utility model relates to a watchdog resetting circuit, which comprises a watchdog resetting chip U1, a photoelectric coupler U2, resistors R1 and R2, a capacitor C1 and diodes D1 and D2, wherein the manual resetting end of the watchdog resetting chip U1 is electrically connected with one end of the resistor R1; the other end of the resistor R1 is electrically connected with one end of the capacitor C1, the power end of the watchdog resetting chip U1 and the power input end VCC of the resetting circuit; the other end of the capacitor C1 is grounded; the watchdog input end and the watchdog output end of the watchdog resetting chip U1 are electrically connected with the negative electrode of the photoelectric coupler U2 respectively through the diodes D1 and D2; the positive electrode of the photoelectric coupler U2 is electrically connected with the power input end VCC of the resetting circuit through the resistor R2; and the base and the emitter of the photoelectric coupler U2 are resetting signal access ends. The watchdog resetting circuit can monitor the running state of a program of a singlechip in real time, so that a phenomenon that endless loop of the singlechip occupies a system bus for a long time is avoided.

Description

A kind of watchdog reset circuit

Technical field

The utility model relates to the reset circuit in the digital circuitry, is specifically related to the watchdog reset circuit in a kind of bus communication system.

Background technology

In the digital communication system that single-chip microcomputer constitutes; Because the operation of single-chip microcomputer causes the normal operation of SCM program to be interrupted, entering endless loop state through the influence that regular meeting receives outside electromagnetic interference and power-supply fluctuation; Because single-chip microcomputer can't operate as normal; Cause the interface microcontroller circuit to take system bus for a long time, cause the digital communication system collapse, be the operation of monitoring singlechip in real time; Improve system reliability, designed the watchdog reset circuit of the real-time monitoring singlechip program run of a kind of ability especially.

Summary of the invention

The purpose of the utility model is: the real-time monitoring singlechip program run of a kind of ability situation is provided, avoids the single-chip microcomputer endless loop, take the watchdog reset circuit of system bus for a long time, to overcome the deficiency of prior art.

In order to achieve the above object; The technical scheme of the utility model is: a kind of watchdog reset circuit; Comprise watchdog reset chip U1, photoelectrical coupler U2, resistance R 1, R2, capacitor C 1 and diode D1, D2; The hand-reset end of said watchdog reset chip U1 is electrically connected with an end of resistance R 1; The other end of resistance R 1 is electrically connected with an end of capacitor C 1, power end and the reset circuit power input VCC of watchdog reset chip U1 simultaneously; The other end ground connection of capacitor C 1, the house dog input end of watchdog reset chip U1 is connected with the negative electricity of photoelectrical coupler U2 through diode D1, D2 respectively with the house dog output terminal, and the positive pole of said photoelectrical coupler U2 is electrically connected with an end of resistance R 2; The other end of resistance R 2 is electrically connected with reset circuit power input VCC, the base stage of photoelectrical coupler U2 with launch very reset signal incoming end.

In technique scheme, said watchdog reset chip U1 is the MAX813LCSA integrated chip.

In technique scheme, said photoelectrical coupler U2 is the TLP521 integrated chip.

The good effect that the utility model had is: after adopting the utility model said structure; During use, when the single-chip microcomputer operate as normal, single-chip microcomputer is through the house dog input end output consecutive pulses signal of I/O mouth to watchdog reset chip U1; The house dog output terminal output high level of watchdog reset chip U1; Light emitting diode is not by luminous among the photoelectrical coupler U2, and illuminated triode ends, and the reset terminal of single-chip microcomputer or communication interface circuit breaks off; When single-chip microcomputer for a certain reason, when program gets into the endless loop state, single-chip microcomputer through the I/O mouth to continuous high level or the low level signal of watchdog reset chip U1 house dog input end output; The inner timer of watchdog chip U1 picks up counting, and the timer timing is to 1.6S, the house dog output terminal output low level of watchdog chip U1; The light emitting diode conducting is luminous among the optically coupled circuit U2; The illuminated triode conducting, the reset terminal of single-chip microcomputer or communication interface circuit is connected reset signal, makes single-chip microcomputer break away from the endless loop state; Avoid interface circuit to take system bus for a long time, caused the digital communication system collapse.

Description of drawings

Fig. 1 is the circuit theory diagrams of a kind of embodiment of the utility model, and wherein, U3 is single-chip microcomputer or communication interface.

Embodiment

Below in conjunction with accompanying drawing and the embodiment that provides, the utility model is further described, but is not limited thereto.

As shown in Figure 1; A kind of watchdog reset circuit; Comprise watchdog reset chip U1, photoelectrical coupler U2, resistance R 1, R2, capacitor C 1 and diode D1, D2; The hand-reset end of said watchdog reset chip U1 is electrically connected with an end of resistance R 1, and the other end of resistance R 1 is electrically connected the other end ground connection of capacitor C 1 with an end of capacitor C 1, power end and the reset circuit power input VCC of watchdog reset chip U1 simultaneously; The house dog input end of watchdog reset chip U1 is connected with the negative electricity of photoelectrical coupler U2 through diode D1, D2 respectively with the house dog output terminal; The house dog input end of watchdog reset chip U1 also is the pulse signal incoming end, and promptly the house dog input end of watchdog reset chip U1 also is the incoming end of single-chip processor i/o mouth output continuous impulse signal, and the positive pole of said photoelectrical coupler U2 is electrically connected with resistance R 2; And resistance R 2 is electrically connected with power supply VCC, the base stage of photoelectrical coupler U2 and the reset signal incoming end of launching single-chip microcomputer very or communication interface.

As shown in Figure 1, said watchdog reset chip U1 is the MAX813LCSA integrated chip, and said photoelectrical coupler U2 is the TLP521 integrated chip.

When the utility model uses; External power supply VCC is electrically connected with 1 pin of watchdog reset chip U1 through resistance R 1; And power-on reset signal is provided for watchdog reset chip U1; 6 pin of watchdog reset chip U1 are connected with the negative electricity of photoelectrical coupler U2 through diode D1, D2 respectively with 8 pin simultaneously, and 6 pin (WDI) of said watchdog reset chip U1 also are the incoming end WD of single-chip processor i/o mouth, and external power supply VCC connects light emitting diode positive pole among the optically coupled circuit U2 through resistance R 2; The illuminated triode of photoelectrical coupler U2 is electrically connected with the reset terminal of single-chip microcomputer or communication interface circuit, 3 pin, the 4 pin ground connection of said door dog reset chip U1.

The watchdog reset circuit device of the utility model is when being used for the digital communication system of single-chip microcomputer formation; The program run of monitoring singlechip in real time; In the single-chip microcomputer operational process, receive the influence of outside electromagnetic interference and power-supply fluctuation, and cause the working procedure of single-chip microcomputer to get into the endless loop state, at this moment; The reset terminal output reset signal of single-chip microcomputer or communication interface; And this reset signal is delivered to the reset signal incoming end of the utility model, avoided the interface microcontroller circuit to take system bus for a long time, improved system reliability.

Claims

1. watchdog reset circuit; It is characterized in that: comprise watchdog reset chip U1, photoelectrical coupler U2, resistance R 1, resistance R 2, capacitor C 1 and diode D1, diode D2; The hand-reset end of said watchdog reset chip U1 is electrically connected with an end of resistance R 1; The other end of resistance R 1 is electrically connected with an end of capacitor C 1, power end and the reset circuit power input VCC of watchdog reset chip U1 simultaneously; The other end ground connection of capacitor C 1; The house dog input end of watchdog reset chip U1 is connected with the negative electricity of photoelectrical coupler U2 through diode D1, diode D2 respectively with the house dog output terminal; The positive pole of said photoelectrical coupler U2 is electrically connected with an end of resistance R 2, and the other end of resistance R 2 is electrically connected with reset circuit power input VCC, the base stage of photoelectrical coupler U2 with launch very reset signal incoming end.

2. watchdog reset circuit according to claim 1 is characterized in that: said watchdog reset chip U1 is the MAX813LCSA integrated chip.

3. watchdog reset circuit according to claim 1 is characterized in that: said photoelectrical coupler U2 is the TLP521 integrated chip.