JPS6065344A - Runaway preventing circuit of microcomputer - Google Patents

Abstract

PURPOSE:To detect the runaway of a microcomputer and to stop a system at the safety side and to prevent the runaway, by providing a pulse generating circuit and an N-notation counter as the peripheral circuits of the microcomputer to transfer a signal. CONSTITUTION:When a microcomputer 1 runs away, the clear pulses are not outputted orderly within TX(N-1)sec from a clear pulse output terminal 4. Therefore, an N-notation counter 3 outputs a carry pulse with the N-th pulse sent from a pulse generating circuit 2. Thus the computer 1 is reset by the carry pulse since the carry terminal of the counter 3 is connected to a reset terminal 7 of the computer 1. In other words, the computer 1 is reset forcibly to its initial state and executes a normal program again.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to an abnormal light prevention circuit for a microcomputer, which is intended to detect unexpected 10-gram execution, that is, % run, of a microcomputer and prevent malfunction of the W-unit. It is a gate.

In recent years, microcomputers have been used in many fields, and the number of devices using microcomputers is increasing, but on the other hand, equipment malfunctions due to noise and runaway microcomputers have become a problem.

This strange light of the microcomputer is generated by the power supply fins and noise propagating in the air, so it is conventionally t', m, and 7. Izufui IV,
5t-f input terminal I), a method has been taken to block the noise propagating in the air by surrounding the microphone with a shield cane. Although it has the effect of increasing p.

The present invention provides a runaway prevention circuit for a microcomputer that can immediately detect any abnormal light in the microcomputer 1 and safely stop the system.

The present invention will be explained with reference to FIGS. 1, 2, and 3.

In the present invention, as a peripheral circuit of the microcomputer (i), a pulse generating circuit (■) that generates a series of pulses with a period of T seconds and an N-ary counter (Kikun) are used as a peripheral circuit of the microcomputer (i). The pulse generated by the pulse generation circuit (phantom) is counted by the N-ary counter (while the counter is connected, the clear pulse of the microcomputer ■ is used to make the counter value 0 before the counter reaches N). A groove is formed to output from the output terminal ■ to the I=I base counter (IT's clear bias input terminal ■.Here, the time required for the counter value to reach S and 7) is the period of the pulse generation circuit. If is T seconds, it is TXN seconds, so if you create a microcomputer program to output a clear pulse from the microcomputer ■ at least every Tx (N-1) seconds, the input pulse will be output from the N-ary counter. Carry pulse (carry pulse) emitted at the N side entrance,
-J- Since the reset voltage that sets the operation of the microcomputer (2) to its initial state is not generated, the microcomputer 0)I'' continues to operate normally.

By the way, for some reason the microcomputer is now 0)
Assuming that the pigeon ran t7, the movement of the pigeon coop is ff1l.
This will be explained using Figure T2.

When the microcomputer ■ lights up, clear/(A/
Since the clear pulse from the bus output terminal ■ is no longer output regularly within Tx (N-1) seconds, the N-ary counter (machi is reset to 1 digit by the fourth pulse of t7 from the pulse generator circuit ■). Then,
Since the carry terminal (■) of the N-adic counter (j) and the reset terminal (■) of the microcomputer (D) are connected, the microcomputer (D) is powered up by this galley bus. Nawara, -7, (ri11 combo (i) t) is forcibly returned to the initial state, and executes the 100th regular b(+gwano).

Next, a case in which the pulse generating circuit (C) and the N-ary counter (2) fail will be explained in the third M. This tlld
Even if the microcomputer (T) is running and clear pulses are not issued regularly, it is not possible to stop the runaway of the N-ary counter (microcomputer 0 because no carry pulse is issued from ■).

In order to prevent this, in the present invention, the -tl base counter (gradient pulse output) T'1M child (help (this) is outputted as it is or divided into % etc. Configuration 1-' is used to connect the input terminal (2) of the microcomputer (terminal) to the input terminal (2) of the microcomputer, and to monitor whether or not the N-adic counter (2) consistently outputs l'il response at a constant period.

If this pulse is not normal, the macro communication (i) cannot prevent - early > t2, so a message to that effect is displayed (in the present invention, (1) In order to stop the operation of the microcomputer ('i) itself, I will create a blog '7. Well, the present invention has a total of 17 yen.

By the explanation in ``2'', it is easy to understand l! As you can see, the Kinoi tjjj dekema f black computer (with a pulse generation circuit ■ and a ti-adic count (ko) as peripheral circuits,
This Rerato microcomputer (j+) checks mutual operation by exchanging signals with J+, and in any case it operates safely without stopping the equipment. is extremely large.

[Brief explanation of the drawing]

Part 1, Fig. 2, and Fig. 3 show the J7 misrun prevention circuit of the microcomputer of the present invention. Status: FIG. 8 shows the status of the pulse generation circuit and N-ary counter circuit at the time of failure. (■)=Microphone 11 Computer (Kai:Pulse 5F=
Main circuit ■ = N7t counter ■ = Clear pulse output terminal ■ = Il rear pulse manual power? rM Ryo・(Mountain=Gari terminal(';)=U set I-MiAko<n, +-=Haru y,
Out)), r<71.7-(Jun=Input terminal 11 de J:''Output one person Ohira 汀上了('(; Shiki company whistle 30

Claims (1)

[Claims] In an electronic circuit using a microcomputer, a pulse generation circuit that continuously emits pulses with a period of 1' seconds.
Then, the pulse generation circuit counts the pulses and outputs all pulses for every N pulses to the carry terminal ■ and the clear pulse input terminal ■ sets the counter value to 0. Pulse output terminal (
'll'X
(N-1) Send counter clear pulse to microcomputer (i) clear pulse output terminal σ)
(L) N'jlf3 Output to the clear pulse input terminal (g) of the counter (3'l), microcomputer (
If the correct counter clear pulse for regular work is no longer output due to abnormality of 0, the carry terminal of the N-ary counter ■
The microcomputer ■ is set to 17" by the caliper pulse, and the pulse output from the pulse output terminal of the Ni counter (■) is inputted from the input terminal (■) of the microcomputer ■, and a close pulse is generated. To the circuit ■ and Jf, the counter (the phantom 8 constant is 1-[computer σ)!, 79, C.7 was turned off, the micro: 1 B1-overnight display prevention circuit.