JPH0462643A - Detecting circuit for program runaway - Google Patents
Detecting circuit for program runawayInfo
- Publication number
- JPH0462643A JPH0462643A JP2174823A JP17482390A JPH0462643A JP H0462643 A JPH0462643 A JP H0462643A JP 2174823 A JP2174823 A JP 2174823A JP 17482390 A JP17482390 A JP 17482390A JP H0462643 A JPH0462643 A JP H0462643A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- circuit
- program
- cpu
- output port
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000004069 differentiation Effects 0.000 claims abstract 4
- 238000001514 detection method Methods 0.000 claims description 6
- 238000010586 diagram Methods 0.000 abstract description 6
- 125000004122 cyclic group Chemical group 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 2
- 239000013256 coordination polymer Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
Landscapes
- Debugging And Monitoring (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、マイクロコンピュータを使用した機器におけ
るマイクロコンピュータのプログラム暴走検出回路に関
するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microcomputer program runaway detection circuit in equipment using a microcomputer.
従来、この種のプログラム暴走検出回路は、タイマー回
路をプログラムにより周期的にリセットし、プログラム
暴走時にタイマー回路がリセットされない場合にマイク
ロコンピュータを使用した機器の電源をＯＦＦしていた
。Conventionally, this type of program runaway detection circuit periodically resets a timer circuit according to a program, and if the timer circuit is not reset at the time of program runaway, the power of a device using a microcomputer is turned off.
上述した従来のプログラム暴走検出回路は、プログラム
にてタイマー動作の設定及びコントロールを行なう為、
外部からのノイズによりタイマー動作の設定が正常でな
くなる場合が生じる。このような時は、プログラムが暴
走してもタイマーが正常に動作しないから暴走検出が出
来ないという欠点がある。In the conventional program runaway detection circuit described above, the timer operation is set and controlled by the program.
External noise may cause the timer operation settings to become incorrect. In such a case, there is a drawback that even if the program runs out of control, the timer does not operate normally, so runaway cannot be detected.
本発明のプログラム暴走検出回路は、プログラムにより
周期的に出力電圧を変化する出力ポートと、この出力ポ
ートの出力電圧を微分する微分回路と、この微分回路の
出力電圧が変化しない時は一定時間後に電源を切断する
駆動回路を有している。The program runaway detection circuit of the present invention includes an output port that changes the output voltage periodically according to the program, a differentiator that differentiates the output voltage of this output port, and a differential circuit that differentiates the output voltage of this output port after a certain period of time when the output voltage of the differentiator does not change. It has a drive circuit that cuts off the power.
次に、本発明について図面を参照して説明する。 Next, the present invention will be explained with reference to the drawings.
第１図は本発明の一実施例のブロック図である。ＣＰＵ
（プログラム実行部）１の出力ポートに微分回路３の
入力側を接続し、微分回路３の出力側を駆動回路５の入
力側に接続し駆動回路５の中にあるスイッチ６の一方に
電源入力を接続し、他方に電源出力を接続したものであ
る。FIG. 1 is a block diagram of one embodiment of the present invention. CPU
(Program execution unit) Connect the input side of the differentiating circuit 3 to the output port of 1, connect the output side of the differentiating circuit 3 to the input side of the drive circuit 5, and input power to one side of the switch 6 in the drive circuit 5. and the power output is connected to the other.
本実施例において、ＣＰＵＩは出力ポートを０Ｎ−ＯＦ
Ｆするプログラムを周期的に実行して、ＣＰＵＩからの
出力ポート信号２に第２図に示す周期的なパルス波形を
作り出す。In this embodiment, the CPUI sets the output port to 0N-OF.
The program F is executed periodically to create the periodic pulse waveform shown in FIG. 2 in the output port signal 2 from the CPUI.
微分回路３はＣＰＵＩの出力ポート信号２が第２図に示
す波形のようにＬＯＷレベルからＨＩＧＨレベルへの変
化があれば、第２図に示す波形の信号４を発生するが、
出力ポート信号２にＬＯＷレベルからＨＩＧＨレベルへ
の変化が無ければ微分回路３の出力信号４は、ＬＯＷレ
ベルのまま変化しない。The differentiating circuit 3 generates a signal 4 having the waveform shown in FIG. 2 when the output port signal 2 of the CPU changes from a LOW level to a HIGH level as shown in the waveform shown in FIG.
If the output port signal 2 does not change from the LOW level to the HIGH level, the output signal 4 of the differentiating circuit 3 remains at the LOW level and does not change.
駆動回路５は微分回路３から送られて来る信号４として
第２図に示すように周期的に立ち上がる波形の信号が入
力され続けていれば電源に接続するスイッチ６はＯＮ状
態のままかわらないが、微分回路３からの信号４がＬＯ
Ｗレベルのままであれば、ＬＯＷレベルになってから一
定時間後に駆動回路５のスイッチ６を切断するものであ
る。If the drive circuit 5 continues to receive a signal 4 sent from the differentiating circuit 3 with a waveform that periodically rises as shown in FIG. 2, the switch 6 connected to the power source will remain in the ON state. , signal 4 from differentiator circuit 3 is LO
If it remains at the W level, the switch 6 of the drive circuit 5 is cut off after a certain period of time after it becomes the LOW level.
プログラム暴走時において、ＣＰＵ１は出力ポートをＯ
Ｎ＠ＯＦＦするプログラムを実行しないから、ＣＰＵ１
の出力ポート信号２には第２図に示す波形は出力されな
い。この為、微分回路３に入力される波形はＬＯＷレベ
ルからＨＩＧＨレベルへの変化が無くなり微分回路３の
出力は、ＬＯＷレベルのまま変化しない。よって駆動回
路５に入力される信号４はＬＯＷレベルのままであり、
駆動回路５はスイッチ６により電源を断する。When the program runs out of control, CPU1 turns the output port OFF.
Since the program that turns N@OFF is not executed, CPU1
The waveform shown in FIG. 2 is not output to the output port signal 2 of . Therefore, the waveform input to the differentiating circuit 3 does not change from the LOW level to the HIGH level, and the output of the differentiating circuit 3 remains at the LOW level. Therefore, the signal 4 input to the drive circuit 5 remains at LOW level,
The drive circuit 5 turns off the power by the switch 6.
ＣＰＵＩでプログラムが暴走してなければ、出力ポート
信号２、微分回路３の信号４には第２図に示す波形の信
号が出力されスイッチ６はＯＮ状態で、電源は入力され
続ける。If the program does not run out of control on the CPU, a signal having the waveform shown in FIG. 2 is output to the output port signal 2 and the signal 4 of the differentiating circuit 3, the switch 6 is in the ON state, and the power continues to be input.
以上説明したように本発明は、プログラム暴走検出回路
に微分回路を使用する事により、ノイズによるＣＰＵの
破損、及びプログラムの暴走に対してマイクロコンピュ
ータ機器の安全を保証できる効果がある。As explained above, the present invention has the effect of guaranteeing the safety of microcomputer equipment against CPU damage due to noise and program runaway by using a differentiating circuit in the program runaway detection circuit.
第１図は本発明の一実施例のブロック図、第２図は第１
図の出力ポート信号２と微分回路３からの信号４の波形
を示した波形図である。
１・・・ＣＰＵ （プログラム実行部）、２・・・ＣＰ
Ｕ出力ボート信号、３・・・微分回路、４・・・微分回
路出力信号、５・・・駆動回路、６・・・電源スィッチ
。
第FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
FIG. 2 is a waveform diagram showing the waveforms of the output port signal 2 and the signal 4 from the differentiating circuit 3 shown in the figure. 1...CPU (program execution unit), 2...CP
U output boat signal, 3... Differential circuit, 4... Differential circuit output signal, 5... Drive circuit, 6... Power switch. No.
Claims (1)
トと、この出力ポートの出力電圧を微分する微分回路と
、この微分回路の出力電圧が変化しない時は一定時間後
に電源を切断する駆動回路を有することを特徴とするプ
ログラム暴走検出回路。It has an output port that periodically changes the output voltage according to a program, a differentiation circuit that differentiates the output voltage of this output port, and a drive circuit that turns off the power after a certain period of time when the output voltage of this differentiation circuit does not change. A program runaway detection circuit featuring:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2174823A JPH0462643A (en) | 1990-07-02 | 1990-07-02 | Detecting circuit for program runaway |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2174823A JPH0462643A (en) | 1990-07-02 | 1990-07-02 | Detecting circuit for program runaway |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0462643A true JPH0462643A (en) | 1992-02-27 |
Family
ID=15985290
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2174823A Pending JPH0462643A (en) | 1990-07-02 | 1990-07-02 | Detecting circuit for program runaway |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0462643A (en) |
-
1990
- 1990-07-02 JP JP2174823A patent/JPH0462643A/en active Pending
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