JPH05134799A - Switch scanning system - Google Patents

Abstract

PURPOSE:To easily input switches arranged in the shape of matrix at high speed by making bidirectional the respective input/output direction in X-direction line and Y-direction line of plural switches arranged in the shape of matrix. CONSTITUTION:The output of an IC 1 is set at H-level, an IC 3i is set in an output mode, and its output is set at L-level. The IC 3o is set in an input mode. When no switch 9 is pressed, the input data of the IC 3o is all at H-level. When any one of the switches 9 is pressed, the input data in the Y-direction line corresponding to the switch 9 is at L-level and the output of an IC 7 is also at L-level. When a switch 9K is pressed, for example, the input data of the IC 3o is at L-level only in Y3 and the others are at H-level. Under such condition, the position in X-direction can be specified from the input data of an IC 5o. Thus, by scanning only the line in which the switch 9 is pressed, the input of the switches can be performed at high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switch scan system which enables input of switches arranged in a matrix at high speed and easily.

[0002]

2. Description of the Related Art In recent years, various switch scan systems have been proposed. A circuit based on such a switch scan system is shown in FIG. The circuit shown in FIG. 3 is a circuit for detecting which of the plurality of switches 109 arranged in a matrix is pressed, and the plurality of switch groups are, for example, a computer keyboard and a control. Each switch 109 corresponds to a keyboard switch of a panel or the like, and each switch 109 is each switch of the keyboard.

Each of the switches 109 is composed of a switch and a diode, the anode terminal of the diode is connected to the X direction line of a plurality of switches arranged in a matrix, and the cathode terminal is connected through the switch in the Y direction. Connected with the line. Therefore, since the X-direction line is connected to the power supply via the resistor, the X-direction line is normally set to the “High” level (hereinafter, simply referred to as the H level), the switch is turned on, and the switch is connected. Only when the Y-direction line is set to the L level, the X-direction line is set to the L level.

In the above-described circuit of the switch scan system, the voltage levels of the Y-direction lines Y1 to Yn of a plurality of switches arranged in a matrix are sequentially set to "Lo".
The scan for shifting to the w "level (hereinafter, simply referred to as the L level) is performed at high speed, and the output (High) of the X-direction lines X1 to Xm of the plurality of switches is performed every line scan.
It is possible to determine which key is pressed by detecting each of r Low).

That is, in this conventional detection system, only one of the n Y-direction lines Y1 to Yn is set to the L level, and the data of the return line at that time is input from the input circuit. The state of the switch on the corresponding scan line is input. Therefore, it is necessary to perform this operation for all scan lines and input the states of all switches.

However, in such a conventional method, since the operation of outputting the L level of the scan line and inputting the return line as described above must be repeated for each scan line, the switch is input once. It took quite a while. Further, if the CPU is made to perform this work, the load is heavy, and the overall throughput is reduced.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a switch scan system which can input switches arranged in a matrix at high speed and easily.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is a switch scan system for inputting the state of each switch 9 of a switch group consisting of a plurality of switches 9 arranged in a matrix, and arranged in the matrix. The input / output directions of the X-direction line and the Y-direction line of the plurality of switches 9 are bidirectional.

According to the switch scan method of the present invention, the X-direction line of a plurality of switches arranged in a matrix, Y
Since the input and output directions of the directional lines are bidirectional, it is not necessary to sequentially perform the switch scan for inputting the state of each switch for each of the Y direction lines.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a circuit diagram of a first embodiment of the switch scan system according to the present invention. As shown in FIG. 1, a plurality of switches 9 arranged in a matrix of m in the X direction and n in the Y direction, and Y-direction ICs 3i, 3o, and X connected to lines in the X-direction and the Y-direction of the matrix. It is constituted by the directions IC5i and 5o. The Y direction IC 3i and the X direction IC 5i are input side ICs, and
The direction IC 3o and the X direction IC 5o are output side ICs.

The input-side IC 3i and the output-side IC 3o are connected by n lines in the Y direction, and the input-side IC 5i
And the output side 5o are connected by m X-direction lines. Further, the n Y-direction lines and the m X-direction lines are connected so as to form a matrix of m X-direction and n Y-direction lines, and the intersections thereof are the X-direction m
And m × n switches 9 arranged in a matrix of n pieces in the Y direction.

Each of the switches 9 is composed of a switch and a diode, the cathode terminal of the diode is connected to the X-direction line of a plurality of switches arranged in a matrix, and the anode terminal is connected through the switch in the Y-direction. Connected with the line.

Next, the input procedure according to this embodiment will be described. First, the output of IC1 is set to H level, IC3i is set to the output mode, and all its outputs are set to L level. Further, the IC 3o is in the input mode. In this state, if 1
Unless the three switches are pressed, the input data of IC3o are all H level. However, if even one switch 9 is pressed, the input data of the Y-direction line corresponding to this switch 9 becomes L level, and the output of the IC 7 also becomes L level. For example, assuming that the switch 9K is pressed, the input data of the IC3 is L level only for Y3, and the other is H level. The output of the IC 7 becomes L level if even one of all the switches is pressed, so this signal is used as an interrupt signal to the CPU.

Here, only the line in the Y direction in which the switch 9K is pressed, that is, the Y3 line is set to H level, and the outputs of the other lines are set to L level. By looking at the input data of the IC 5o in this state, the position in the X direction can be specified. That is, only the X3 line becomes the H level, and the other lines become the L level. IC3i for all Y lines of this L level
By changing the output of the switch and inputting the data at that time from the IC 5i, the states of all m × n switches can be input.

According to this method, unlike the conventional method, it is not necessary to scan all the scan lines, and only the line on which the switch is pressed may be scanned. Normally, at most two switches are pressed at the same time. In this case, only two lines need be scanned. As a result, the scan time is shorter than in the conventional method, so that all the switches can be input at high speed. Also, since the processing of the CPU is reduced,
The time to suspend other work is also reduced. As a result CPU
Throughput is improved.

This means that the greater the number of scan lines, the more advantageous the conventional method becomes.

FIG. 2 shows a second embodiment of the switch scan system according to the present invention. As shown in this figure, the IC1 connected to the lines in the X and Y directions of the matrix
3, 15 are PLD (Programmable Log)
ic Device, PAL (Programmable
e Array Logic)) Bidirectional IC.

The input procedure according to this embodiment will be described below.

First, as a procedure 1, the output of IC1 is set to H level and IC15 is set to the output mode. This IC1
The output of No. 5, that is, the output of the Y direction line is all at the L level. Further, the IC 13 is in the input mode. In this state, if no switch is pressed, IC1
The input data of 3 are all at H level. However, if at least one switch is pressed, the input data of the corresponding line of IC13 becomes L level, and the output of IC7 also becomes L level. For example, if the switch 9K shown in FIG. 2 is pressed, the input data of the IC 13 is Y
Only 3 lines are at L level and the other lines are at H level. I
The output of C7 becomes L level if even one of all the switches is pressed. Therefore, if this signal is used as an interrupt signal to the CPU, the process of step 2 can be triggered.

Next, in procedure 2, first, the L level of the output of IC7 is used as a trigger to set the output of IC1 to the L level,
The IC 15 is in the input mode and the IC 13 is in the output mode. Of the lines that were L level of the input data of the IC 13 obtained in the procedure 1, only one line is set to H level and the other lines are set to L level. For example, switch 9K as in step 1
If is pressed, only the Y3 line is set to the H level and the outputs of the other lines are set to the L level. I in this state
The position in the X direction can be specified by looking at the input data of C15. That is, if the switch 9K is pressed, only the X3 line becomes the H level and the other lines become the L level.

Therefore, by changing the output of the IC 13 only for all the L level Y lines obtained in the procedure 1, in other words, for the L level Y line, the data at that time is input from the IC 15 to obtain m × n. You can enter the status of all switches.

Further, the present invention may be modified as follows. That is, without using the IC 7 of FIG. 1, the CPU constantly monitors the input data of the IC 13 in the state of the procedure 1 and
The process of step 2 may be performed only when there is L level input. By doing so, it becomes unnecessary to use the interrupt function.

As described above, according to the switch scan method of this embodiment, the input and output directions of the X direction line and the Y direction line of the plurality of switches arranged in a matrix are bidirectional. The input time of the switch can be shortened and the load on the input processing CPU can be reduced.

[0024]

As described above, according to the switch scan method of the present invention, the input and output directions of the X direction line and the Y direction line of the plurality of switches arranged in a matrix are bidirectional. It is possible to input the states of a large number of switches at high speed with simple processing.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment according to the present invention.

FIG. 3 is a circuit diagram of a conventional example.

[Explanation of symbols]

 1 IC 3 Y-direction line IC 5 X-direction line IC 7 IC 9 switch

Claims (1)

[Claims] 1. A switch scan system for inputting the state of each switch of a switch group composed of a plurality of switches arranged in a matrix, wherein the X-direction line and the Y-direction line of the plurality of switches arranged in a matrix are provided. A switch scan method characterized in that each input / output direction is bidirectional.