JPS5844258B2 - Interrupt control method for electronic control equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A phenomenon such as a power outage occurs in an electronic arithmetic and control unit that is composed of a central arithmetic and control unit (hereinafter abbreviated as CPU), a random access memory (hereinafter abbreviated as RAM), human power equipment, etc. (This is referred to as a power failure interrupt phenomenon for normal operation control, and the control function performed by the control unit in this case is referred to as interrupt control). It is necessary to protect the data stored in the CPU, RAM, etc. by blocking invalid signals from being input to the control unit.

The present invention attempts to effectively control interrupt phenomena such as power outages to the above-mentioned normal operation control device with an extremely simple circuit configuration.

Examples thereof will be described below.

Here, as shown in Fig. 1, there is a control unit S composed of a CPU, ROM, and RAM, and a keyboard KB as an input device.
, an electronic cash register equipped with a printer PR as an output device will be explained in detail.

In Figure 1, Tn is the scanning signal of the keyboard KB, Kn is the output signal of the keyboard KB, and ADl is the ROM
address signal, AD2 is the address signal of RAM, lN
5T is a processing command signal output from the ROM to the CPU;
D is data, and Pc is a signal that controls the printer PR.

FIG. 2 shows a circuit diagram of the mode changeover switch MSW provided on the keyboard KB. As is clear from the flowchart showing the operation of the cash register in FIG. If it is determined that the terminal REG is connected, sales registration processing is performed. If it is determined that the mode changeover switch MSW is connected to terminal In each case, sales settlement processing is performed.

Also, the mode selector switch MSW is REG, X.

If it is determined that it is not connected to any terminal of Z, the third
All of the determination processing of the mode changeover switch MSW in the figure is N.
Since the determination is O, it is not possible to proceed to each processing routine, and loop 1 is repeated.

In this case, the cash register stops all processing, so it will not malfunction due to invalid input signals.

FIG. 4 is a block diagram showing power supply to the control unit S and printer PR.

AC input is connected to constant voltage circuits PI and P via power transformer T.
2.

As a result, the AC input to the printer PR is the constant voltage circuit P1.
The voltage VFR is supplied as a constant voltage VFR.

Therefore, at the time of power outage, VFR output is stopped.

Further, the constant voltage circuit P2 supplies a stabilized output to the control section S, and also performs floating charging on the battery B.

Therefore, in the event of a power outage, battery B immediately starts discharging and continues to supply power to control unit S.
The control unit S can continue operating even during a power outage.

FIG. 5 shows the scanning signal Tφ of the mode changeover switch MSW, the rectified voltage VFR1 of the AC power source, and the output Tφ·■PR of the AND gate G1 of the scanning signal Tφ and the rectified AC power voltage VFR.

That is, as is clear from the connection diagram of the mode changeover switch MSW in FIG. 2, the scanning signal Tφ is processed by the AND gate G1 using the output VFR of the AC power supply.
When the AC power is on, the scanning signal Tφ is output from the gate G1, but during a power outage, the scanning signal Tφ is output from the gate G1.
Output from is stopped.

Therefore, the mode changeover switch MSW is connected to the terminals REG, X, and Z.
The scanning signal Tφ is connected to the input line 1 to the control unit S regardless of where it is connected. 2. I can't get through to.

Therefore, the control unit S determines that the mode selector switch MSW is not connected to any of the terminals RBG, X, and Z, and as is clear from the flowchart in FIG.
Repeat loop 1.

In this case, the control section S cannot proceed to each processing routine and all of the processing is stopped, so that malfunctions due to invalid input signals will not occur.

As explained above, according to the present invention, in the case of an interrupt during a power outage, data in the control unit is prevented from disappearing by supplying power from a rechargeable battery, and the scanning signal of the mode changeover switch of the control unit is blocked by gate processing. By doing so, it is possible to stop all the processes of the control section and prevent changes in data due to input of an invalid input signal to the control section.

In addition, in the above explanation, the behavior f when the AC power supply is interrupted is
'F= is explained here, but it can be used in the same way when there are other interrupts.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a device to which an interrupt control method for an electronic control device according to an embodiment of the present invention is applied, FIG. 2 is a detailed configuration diagram of its main parts, FIG. 3 is a flowchart of the above device, and FIG. The figure is a configuration diagram of the power supply circuit of the above device, and FIG. 5 is an operating waveform diagram of the above device. CPU...Central processing control unit, ROM...
...Read-only memory, RAM...Random access memory, MSW...Mode changeover switch, G1...AND gate.

Claims (1)

[Claims] 1. A battery is connected to a control unit consisting of a central processing unit, a random access memory, etc., and configured so that the data stored in the memory does not disappear even in the event of an AC power outage, and the processing operation of the central processing unit is switched. The scanning signal for detecting the switching position of the change-over switch is gated on the input side of the mode change-over switch for use by an interrupt signal such as power outage information of the AC power supply, and the scanning signal is not input to the change-over switch when the AC power supply is stopped. an interrupt of an electronic control unit configured such that a gate circuit is provided, and when the scanning signal is not output from the gate circuit, the central processing unit does not proceed with any processing operations regardless of the switching position of the changeover switch; control method.