JPH02252014A - Switch input circuit - Google Patents

Abstract

PURPOSE:To make connection of mXn switches without increasing input or output terminals possible and to detect multiple depression by providing the switch input circuit with a switch circuit for connecting one or more output terminals of a microcomputer to two or more input terminals only by turning on a switch. CONSTITUTION:The signal lines of terminals P1 to P4 of the microcomputer 1 intersect with the signal lines of terminals P5 to P7 like a matrix and switches 01 to 12 are connected to the intersecting points. In addition, three signal lines are allowed to intersect with the signal lines of the terminals P1 to P4, switches 13 to 24 are connected to the intersecting points and diodes 2a to 2f are connected to the signal lines by a prescribed method so that each signal line is connected to two diodes or less. When a switch 19 is depressed, the microcomputer 1 generates pulses to the terminals P1 to P4 at time t1 to t4, and at the time t2 pulses are inputted to the terminals P6, P8 and the microcomputer 1 decides the depression of the SW 19. Since pulses are successively inputted to the P5 to P7 at the time t5 to t7, but no pulse is inputted to the P1 to P4, no depression of other switches is decided. The depression of two switches also is approximately similarly decided. In said constitution, mXn switches can be inputted without increasing I/O terminals and multiple depression can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a switch input circuit using a microcomputer when the number of switches is large.

[Conventional technology]

A conventional switch input circuit is, for example, disclosed in Japanese Utility Model Application No. 54-172.
As described in Japanese Patent No. 622, as a keyboard for a microcomputer, one output terminal and one input terminal to the microcomputer were connected to the switches (keyboard) of switches arranged in a matrix.

[Problem to be solved by the invention]

In the above conventional technology, in a microcomputer consisting of a group of 1 m output terminals and a group of n input terminals, m
Only n switches can be connected, and if more switches are required, it is necessary to increase the number of input terminals or output terminals of the switch input circuit.

The present invention allows inputting more switches than mXn without increasing the number of input terminals 6 or output terminals of the switch input port a, even in the above-mentioned microcomputer, and further prevents malfunctions due to multiple presses of switches. An object of the present invention is to provide a switch input circuit that can detect multiple presses.

[Cenari to solve problems]

The above object is to provide a switch circuit that connects one or more output terminals and two or more input terminals, or two or more output terminals and one or more input terminals when one or more switches are pressed;
This is accomplished by adding this to a conventional switch input circuit.

In addition, in order to prevent malfunctions that occur when the added switch is pressed multiple times by adding the switch circuit described above, it is necessary for the microcomputer to
Switch the unit from input operation to output operation and output a signal.
This is performed by detecting whether or not the above-mentioned signal is input to this terminal group in an output terminal detailed input operation.

[Operation] Conducting the added switch using the newly installed switch circuit 1. Therefore, a signal output from one output terminal is input to two or more input terminals.

Microcompico, -Yu checks which input terminal of the input terminal group the signal is input to, and by detecting that the signal is input to two or more input terminals, the added switch and one A microcomputer that can distinguish between two output terminals and a conventional switch that conducts one input terminal sequentially switches one of the input terminals from input operation to /J5 force operation and outputs a signal. do,
At this time, if the output terminal group is set to input operation and the above-mentioned signal is input to any of the terminal group, the microcomputer can detect that two or more switches are conductive, thereby preventing malfunction.

(Example〕 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the switch input circuit according to the present invention. FIG. 2 is a circuit diagram of each switch shown in FIG. Of the 8 input/output terminals above, signal lines connected to terminals P1 to P4, terminals 15 to P7
The signal lines connected to each other intersect in a matrix, and at each intersection there are switches O1 to O1 consisting of the circuit shown in Figure 2.
Connect 12.

Further, three signal lines are made to intersect with the signal lines connected to the terminals P1 to P4, and switches 13 to 24 made of the circuit shown in FIG. 2 are connected to each intersection point.

A total of six diodes 2a to 2f, two for each signal line, are connected to the three signal lines so that the key switch side becomes the anode. The cathodes of diodes 2a to 2c are all connected to terminal P8. Diodes 2d-2f are connected to terminals P7-P8, respectively.

FIG. 3 is a timing diagram of each input/output terminal when the switch 19 in FIG. 14 is pressed, and the microcomputer sequentially generates pulses at terminals P1 to P4 from time 1-1 to t4.

If switch 19 is pressed, terminal P is activated at time t2.
6 and terminal P8, and the microcomputer 1 determines that the switch 19 is pressed.

Further, the micro combi coater 1 sequentially generates pulses at the terminals P5 to P7 from time t5 to time t7. At this time,
Since no pulse is input to the terminal PI-P4, it is determined that no other switch is pressed.

FIG. 4 is a timing diagram of each input/output terminal when both switch 19 and switch 07 are pressed.

If switch 19 and switch 07 are pressed,
The period from time t1 to t4 is the same as when only the switch 19 is pressed, but from time t5 to t7, the terminal P
When pulses are sequentially output from 5 to P7, at times 1 and 6
A pulse is input to terminal P2. As a result, the microcomputer 1 determines that a switch other than switch 19 has been pressed.

In the circuit of FIG. 1, the diode 28 of the switch circuit
Even if the polarity of ~2f is reversed and the input/output terminal group of the microcomputer is operated in the opposite direction, the output terminals of two or more switches and the input terminals of the microcomputers J and above are electrically connected. good.

In a conventional switch input circuit, a microcomputer with 8 input/output terminals can only connect 4×4=16 key switches, but in this embodiment, 4×6 key switches can be connected.
= 24 key switches can be connected, which means 8 extra key switches can be connected compared to the conventional one.

In addition, if there are 16 input/output terminals, 8×8=64
In this example, 8×14=112
It is possible to connect 48 additional key switches compared to the conventional type.

(Effects of the Invention) As explained above, according to the present invention, many key switches can be connected to a microcomputer, so a multifunctional switch input circuit can be provided, and multiple key switch presses can be detected. This makes it possible to prevent malfunctions caused by multiple presses, thus solving the problems of the prior art described above.

A switch input circuit with excellent functionality can be provided.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the switch input circuit according to the present invention, FIG. 2 is a circuit diagram of each switch shown in FIG. 1, and FIG. 3 is a case where switch 19 in FIG. 1 is pressed. FIG. 4 is a timing diagram of each input/output terminal when both switch 19 and switch 07 are pressed. 1... Microcomputer, 2a-2f... Diode (switch circuit), 01-24... Matrix switch, PI-P8... Input/output terminal (PI-
P4...output terminal, P5-P8...input terminal). 1. Figure 32. 2. Figure 1: Microcomputer 2 to 2: Diodes O1 to 2+: Matrix connection diagram

Claims (1)

[Claims] 1. In a switch input circuit consisting of a microcomputer equipped with switches arranged in a matrix and a group of input/output terminals, the output of one or more microcomputers can be controlled by making one of the switches conductive. A switch input circuit comprising a switch circuit that connects a terminal to input terminals (or two or more output terminals and one or more input terminals) of two or more microcomputers. 2. In claim 1, one input terminal of the input terminal group is sequentially switched from an input operation to an output operation to output a signal, and it is detected whether or not the signal is input to the output terminal group. A switch input circuit characterized in that it detects that two or more switches are turned on at the same time.