CN204288206U - A kind of watchdog circuit with defencive function - Google Patents
A kind of watchdog circuit with defencive function Download PDFInfo
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- CN204288206U CN204288206U CN201420674067.9U CN201420674067U CN204288206U CN 204288206 U CN204288206 U CN 204288206U CN 201420674067 U CN201420674067 U CN 201420674067U CN 204288206 U CN204288206 U CN 204288206U
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- microprocessor
- watchdog circuit
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Abstract
The utility model provides a kind of watchdog circuit with defencive function, and its output terminal is connected with power remove module by a triode, and when circuit continuous reset, power remove module can make switch close, thus reaches to the object of microprocessor power-off.In addition, the utility model watchdog circuit also has that structure is simple, the advantage of low cost of manufacture.
Description
Technical field
The utility model relates to field of microprocessors, particularly relates to a kind of watchdog circuit with defencive function.
Background technology
Computer network is related to the stable sustainable development of national economy, therefore requires higher to its stability and reliability.And system often occurs that in real work program runs dead situation, the generation of this situation often brings unnecessary trouble.If microprocessor short circuit or other reasons cause feeding dog, so house dog will give microprocessor reset signal always, may cause the damage of microprocessor like this.
Current watchdog circuit design, mainly comprises the control realizing house dog by trigger.
Chinese patent (201320025347.2) discloses and a kind ofly realizes the method that controls house dog and done certain filtering process reducing extraneous interference by trigger.But in fact do not do protection circuit.Such device is just likely destroyed thus leads to system abnormity.
In addition, mainly through making a filtering circuit at input end to improve the antijamming capability of system in prior art, but often because the feeding-dog signal of microprocessor is by external environmental interference, thus cause house dog to can not receive feeding-dog signal, and then cause resetting system again.
Utility model content
In view of the above problems, the utility model provides a kind of watchdog circuit with defencive function.
The technical scheme that the utility model technical solution problem adopts is:
A kind of house dog electricity with defencive function, wherein, comprising: watchdog chip, microprocessor, power remove module, switch module and power module;
Wherein, described switch module is connected with described microprocessor module, described power remove module and described power module respectively; Described power remove module is also connected with described microprocessor; Described watchdog chip is connected with described microprocessor chip.
Described watchdog circuit, wherein, described power remove module comprises two d type flip flops, and each described d type flip flop comprises a Clock Signal pin.
Described watchdog circuit, wherein,
Described watchdog chip comprises WDO pin and WDI pin;
Described microprocessor comprises RST pin and GPIO port;
Described power remove module comprises 1CLK pin, 2CLK pin, CLR pin and PRE pin;
Described power module comprises a VCC;
Wherein, described WDO pin is connected with described RST pin, and described WDI pin is connected with described GPIO port, and described WDO is connected with described 2CLK pin with described 1CLK pin respectively; Described CLR pin is all connected with described VCC with described PRE pin.
Described watchdog circuit, wherein, described watchdog circuit also comprises a triode;
Described WDO pin is connected with described 1CLK pin and 2CLK pin by described triode.
Described watchdog circuit, wherein, described watchdog chip is SGM-760 chip.
Described watchdog circuit, wherein, described power remove module is SN74AHC74DR chip.Technique scheme tool has the following advantages or beneficial effect:
The output terminal with the watchdog circuit of defencive function of the present utility model is connected with power remove module by a triode, and when circuit continuous reset, power remove module can make switch close, thus reaches to the object of microprocessor power-off.
Accompanying drawing explanation
With reference to appended accompanying drawing, to describe embodiment of the present utility model more fully.But, appended accompanying drawing only for illustration of and elaboration, do not form the restriction to the utility model scope.
Fig. 1 is the structural representation of the utility model watchdog circuit;
Fig. 2 is the circuit diagram of watchdog circuit in the utility model embodiment.
Embodiment
The utility model provides a kind of watchdog circuit with defencive function, mainly comprises watchdog chip, power remove module, switch module and power module.
As shown in Figure 1, watchdog chip is connected with microprocessor, and power remove module was both connected with microprocessor, and be also connected with switch module, switch module is also connected with a power module with microprocessor respectively simultaneously.
Below in conjunction with a specific embodiment, watchdog circuit of the present utility model is described in detail.
Watchdog chip in the watchdog circuit of the present embodiment adopts SGM-760 chip.When microprocessor normally works, the GPIO pin in watchdog chip " feeds dog " can ceaselessly to it, if exceed certain hour not feed dog, so its WDO pin can output low level reset to microprocessor.
Power remove module in the watchdog circuit of the present embodiment selects SN74AHC74DR chip, and this SN74AHC74DR chip comprises two d type flip flops.After its CLK pin detects two rising edges, 2Q pin will export high level and be closed by switching tube, and the power supply of such microprocessor will cut off thus shutdown system.
Switch module in the watchdog circuit of the present embodiment is made up of PMOS, and when the 2Q pin of SN74AHC74DR exports high level, PMOS is ended, when 2Q pin output low level time, and PMOS conducting.
Fig. 2 depicts the watchdog circuit circuit diagram in the present embodiment, as shown in the figure, WDO pin in watchdog chip (SGM-760) is connected with the RST pin in microprocessor (CPU), and the WDI pin in watchdog chip (SGM-760) is connected with the GPIO port in microprocessor (CPU); In addition, this WDO pin is connected with 1CLK with 2CLK in power remove module (SN74AHC74DR) by triode Q1; CLR pin in power remove module (SN74AHC74DR) is all connected VCC with PRE pin; 1D and 2/Q in power remove module (SN74AHC74DR) is connected directly between together, and 2Q is as output, and the grid of itself and PMOS links together.
The principle of the utility model watchdog circuit is as follows:
When watchdog chip (SGM-760) first time exports reset signal time, WDO pin jumps to low level by high level, thus produces a negative edge.When obtaining a rising edge after the effect of Q1 phase inverter.According to the truth table of power remove module (SN74AHC74DR), when its CLK pin is when rising edge, output terminal Q1 just can change.
When second reset signal arrives time, Q2 holds level change, and power remove module is actually a binary skill counter, and when counting reaches two rising edges time, Q2 will export high level, thus PMOS is ended.
In this way, the power supply of microprocessor is just disconnected, system stalls, thus plays a protective role.
Visible, when microprocessor is in program race death situation state, then watchdog chip will export a reset signal, will work on after microprocessor reset.When microprocessor does not feed dog to house dog due to reasons such as internal short-circuit, open circuit or loose contacts; then watchdog chip ceaselessly will export reset signal; by watchdog circuit of the present utility model; when watchdog chip is double or more export reset signal time, then power remove module can turn off the power supply of microprocessor thus protection microprocessor.
In sum; microprocessor power supply source when watchdog chip can not get feeding-dog signal, can not only cut off, to protect microprocessor by watchdog circuit of the present utility model; also because its structure is simple, the cost in actual application is reduced greatly.
For a person skilled in the art, after reading above-mentioned explanation, various changes and modifications undoubtedly will be apparent.Therefore, appending claims should regard the whole change and correction of containing true intention of the present utility model and scope as.In Claims scope, the scope of any and all equivalences and content, all should think and still belong in intention of the present utility model and scope.
Claims (6)
1. there is a watchdog circuit for defencive function, it is characterized in that, comprising: watchdog chip, microprocessor, power remove module, switch module and power module;
Wherein, described switch module is connected with described microprocessor module, described power remove module and described power module respectively; Described power remove module is also connected with described microprocessor; Described watchdog chip is connected with described microprocessor chip.
2. watchdog circuit as claimed in claim 1, it is characterized in that, described power remove module comprises two d type flip flops, and each described d type flip flop comprises a Clock Signal pin.
3. watchdog circuit as claimed in claim 2, is characterized in that,
Described watchdog chip comprises WDO pin and WDI pin;
Described microprocessor comprises RST pin and GPIO port;
Described power remove module comprises 1CLK pin, 2CLK pin, CLR pin and PRE pin;
Described power module comprises a VCC;
Wherein, described WDO pin is connected with described RST pin, and described WDI pin is connected with described GPIO port, and described WDO is connected with described 2CLK pin with described 1CLK pin respectively; Described CLR pin is all connected with described VCC with described PRE pin.
4. watchdog circuit as claimed in claim 3, it is characterized in that, described watchdog circuit also comprises a triode;
Described WDO pin is connected with described 1CLK pin and 2CLK pin by described triode.
5. watchdog circuit as claimed in claim 1, it is characterized in that, described watchdog chip is SGM-760 chip.
6. watchdog circuit as claimed in claim 1, it is characterized in that, described power remove module is SN74AHC74DR chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420674067.9U CN204288206U (en) | 2014-11-12 | 2014-11-12 | A kind of watchdog circuit with defencive function |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420674067.9U CN204288206U (en) | 2014-11-12 | 2014-11-12 | A kind of watchdog circuit with defencive function |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204288206U true CN204288206U (en) | 2015-04-22 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420674067.9U Expired - Fee Related CN204288206U (en) | 2014-11-12 | 2014-11-12 | A kind of watchdog circuit with defencive function |
Country Status (1)
| Country | Link |
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| CN (1) | CN204288206U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110380873A (en) * | 2019-08-26 | 2019-10-25 | 深圳市三旺通信股份有限公司 | A kind of device and method for avoiding the crash of POE control system from still powering |
-
2014
- 2014-11-12 CN CN201420674067.9U patent/CN204288206U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110380873A (en) * | 2019-08-26 | 2019-10-25 | 深圳市三旺通信股份有限公司 | A kind of device and method for avoiding the crash of POE control system from still powering |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150422 Termination date: 20181112 |