JPH01246623A - Switch input device - Google Patents

Abstract

PURPOSE:To reduce the number of ports of a microcomputer which discriminates a switch input by assigning one output port to the whole of switches and assigning one input port to a pair of switches and detecting a signal with each input port. CONSTITUTION:One terminal of each of switches 1a and 1c is connected to an output terminal 5c of a microcomputer 5, and the other terminals are connected to one-side terminals of switches 1b and 1d. The connection part between switches 1a and 1c is connected to an input terminal 5a of the microcomputer 5. The output from the output terminal 5c is set to the high level, and it is judged that the switch 1c is not through and the control is returned from a switch input discriminating routine when the input terminal 5a is in the low level. When the input terminal 5a is in the high level, it is temporarily judged that the switch 1a or 1c is thrown and the device is held for a certain time. Next, the output from the output terminal 5c is set to the low level to discriminate the level of the input terminal 5a. Switches 1b and 1d are discriminated in the same manner.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a small switch input device in an apparatus having a plurality of input switches.

2. Description of the Related Art In recent years, with the development of microcomputers, switch input devices that are capable of complex control and are equipped with a large number of switches have come into use. Conventionally, this type of switch input device has had a configuration as shown in FIG. That is, the terminals of the plurality of switch groups 1o1 are respectively connected to input terminals 102a, 102b and output terminals 1020, 102d of the microcomputer 102, and when any one of the switch groups 1o1 is inputted, the microcomputer 102 outputs After sequentially outputting terminals 102a and 102b, it was configured to detect whether or not there was an input at input terminal 1020.1o2d to determine which switch in switch group 1o1 was input.

For example, when the switch 101a is operated, the output current from the input terminal 102a is transmitted to the input terminal 102c, and is compared and calculated within the microcomputer 102.
This is to recognize that the switch 101a has been input.

Problems to be Solved by the Invention In such a conventional configuration, the relationship between the number of switches required by the switch group 1o1 and the input/output terminals required by the microcomputer at that time is as shown in Table 1 below.

(Table 1) As the number of switches increases, the number of connection terminals gradually increases, but since the number of input/output terminals of the microcomputer 102 is limited, the remaining input/output terminals are used for purposes other than switches. The problem is that even if the number of switch operation inputs increases, the corresponding input/output control will be restricted.

The present invention solves these problems by connecting multiple switches with a smaller number of terminals than in the past, increasing the number of terminals that can be used for other purposes, and expanding the scope of use of microcomputers. The object of the present invention is to provide a switch input device that can perform the following functions.

Means for Solving the Problems To achieve this object, the present invention provides a pair of switches in which a common terminal is provided on the common line of two input switches connected in series, and a switch group in which a plurality of these pairs of switches are connected in parallel. , a set of switch group terminals provided at both ends of the switch group, and a microcomputer connected to the switch group, one of the switch group terminals being connected to one output terminal provided on the microcomputer. the other of the switch group terminals is connected to the high voltage side of the power supply of the microcomputer, the common terminal is connected to one of a plurality of input terminals provided on the microcomputer, and A voltage equal to the power supply voltage of the microcomputer and a voltage lower than the power supply voltage are alternately generated from the output terminal, and one switch in the switch group receives the input from the voltage value input to one of the multiple input terminals. It has a configuration that determines whether it has been done.

Function: According to the above configuration, one output port is provided on the entire switch,
A microcomputer that allocates one input port to a pair of switches and determines the switch input by detecting the signal at each input port when high and low output signals are intermittently applied from the output port. The number of ports can be reduced.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2.

As shown in the figure, one terminal of switches 1a and 1c is
The terminals of the switches 1a and 1a are connected to one side of the switches 1b and 1d, and the input terminal of the microcomputer 5 is It is connected to the terminal.

In the above configuration, a flowchart for actually inputting a switch is shown in FIG. 2, and will be explained below.

However, for the sake of clarity, the input discrimination method for switches 1a and 1c will be explained first.

First, in step 1o, the output t from the output terminal 6o
- Set to high level and switch 1a and 1c in step 20.
is connected to the input terminal 6a, and step 3o
Determine whether the input state is high level or low level with f
Ru. Low level Nara ld', determines that switch 1e is not input and exits from the switch input determination routine.
If the level is NO/I, switch 1a or switch 1C
is assumed to have been input, and the process waits for a certain period of time in step 4o. Next, in step 50, the output from the output terminal 50 is set to low level, and in step 6o, it is input to the input terminal 6a, and in step 7o, the input signal is determined. If the signal is at a low level, a flag is set in step 9o indicating that the switch 1C has been input. If the input signal is at a high level, a flag is set in step 80 indicating that the switch 1a has been input. Further, in step 100, the system waits for a certain period of time, sets the output from the output boat 5o to a high level in step 11o, inputs it from the input terminal 2a in step 12o, and in step 130
If the input signal is at a low level, the switch input determination routine is exited. If the input signal is at a high level in step 130, response processing for that switch is performed in step 140 based on the flags set in steps 8o and 9o. After that, the process exits from this switch input determination routine.

To summarize the above operations, the relationship between the output terminal 5o and the input terminal 6a and the response state of the switch can be summarized in Table 2.

As described above, the input states of the two switches are determined by sequentially applying high-level, low-level, and high-level signals from one output terminal 20 and inputting and determining them at one input terminal 6a. This makes it possible to reduce the number of terminals used for switches of the microcomputer 6.

The above operation explanation is 0N-OF of switches 1a and 1c.
F is determined, but the input terminals of the switches 1b and 1d are 2b, and the other operations are the same.

Table 3 below shows the relationship between the number of switches and the number of input/output terminals.

Effects of the Invention As is clear from the description of the above embodiments, according to the present invention,
By reducing the number of microcomputer terminals connected to the switch, the microcomputer terminals can be used effectively for other purposes, creating an excellent switch input device that fully utilizes the microcomputer's capabilities. This is something that can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a switch input device according to an embodiment of the present invention, FIG. 2 is a flow chart showing an example of a program for determining switch input, and FIG. 3 is a circuit diagram of a conventional switch input device. . 1...Switch group, 1a to 1d...Switch, 2...Switch pair, 3...Common terminal, 4...Switch group Terminal, 6...
・Microcomputer, 5a. 6b...Input terminal, 6o...Output terminal. Name of agent: Patent attorney Toshio Nakao and 1 other person f-
11 Sui Tuna (i to 1st figure 1 word d-・-s4-/+
2-・-su 4 chis dō 3---chi'<kWrrte--sui tuna, humiliation sheeptate eid 5°-my 70 cosopieda 5a, 5b--alone jJiM+ 5o・-de no a+ 2nd figure

Claims (2)

[Claims] (1) A switch pair with a common terminal on the common line of two input switches connected in series, a switch group in which a plurality of these switch pairs are connected in parallel, and a set of switch group terminals provided at both ends of this switch group. and a microcomputer connected to the switch group, one of the switch group terminals is connected to one output port provided on the microcomputer, and the other of the switch group terminals is connected to the power supply of the microcomputer. A switch input device, wherein the common terminal is connected to one of a plurality of input ports provided in the microcomputer. (2) A voltage equal to the power supply voltage of the microcomputer and a voltage lower than the power supply voltage are alternately generated from the output port provided on the microcomputer, and the switch group is Claim 1 for determining whether one switch in the
The switch input device described in section.