JPS61210417A - Key input device - Google Patents

Abstract

PURPOSE:To make unnecessary the back flow preventing diode and to execute the correct initial setting by deciding that the read data are made invalid when the input of the mechanical switch is detected and the read data are made valid when the input is not detected. CONSTITUTION:First, the condition of I N0-I N3 is read, the contents are checked and it is decided whether or not mechanical switches 8-11 are on. When an on condition of either of the switches 8-11 is detected, the read initial setting data are made invalid. When any on condition is not detected, the read initial setting data are made valid and the initial setting by the reading contents is executed. The time necessary to such a decision is very short, and short compared with the response speed of a human being and the return time of the mechanical switch, and therefore, without providing the back flow preventing diode, the interference of the diode switch and the mechanical switch can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a key input device having a structure in which a diode switch for initial setting is connected to a reading circuit of a mechanical switch.

2. Description of the Related Art Conventionally, this type of key input device has been used in devices to which a microcomputer is applied, such as a synthesizer tuner.

FIG. 3 shows a conventional key holding device. 1 is a microcomputer, for example, M N manufactured by Matsushita Electronics Co., Ltd.
1400 etc. are used. 2 and 3 are diode switches, 4 to 7 are backflow prevention diodes, and 8 to 11 are mechanical switches.

FIG. 4 shows a flowchart of the key input device of FIG. The microcomputer 1 first sets outl to "H" level (a-i), sets out2 to "L" (L/bevel a-2), and inputs from lN0 to lN3 (a-3).
It can be determined that the diode switch 2.3 connected to i, INO, and IN2 is ONL, and that the diode switch is inserted in INO and IN2 (a-4). or,
Similarly, it is possible to insert diode switches in outl, INl, and IN3, so outl and IN
A predetermined operation can be performed by a combination of diode switches inserted between O and IN3, and is usually used as an initial setting. In addition, as shown in Fig. 1 (when outl is at the "H" level and mechanical switches 8 and 9 are pressed, if there is no backflow prevention diode 4.5, then the diode switch 2 will pass through the mechanical switch 8.9). ,INl
A current flows through the circuit, which is equivalent to when a diode switch is inserted between outl and INl, resulting in malfunction. To prevent this, backflow prevention diodes 4 to 7 are inserted. Also, key input is outl “L” (a-5)
and set out2 to H″T (a-6) L, te,■
The state of the mechanical switch input from NO to IN3 is read (a-7), and a predetermined operation is performed according to the read state (a-8).

Problems to be Solved by the Invention As described above, in the conventional configuration, the backflow prevention diode 2.3 was required to prevent interference between the initial setting diode switch 2.3 and the mechanical switch 8.9.

An object of the present invention is to provide a key input device that can eliminate the need for a backflow prevention diode.

Means for Solving the Problems The key input device of the present invention is configured to perform initial setting by connecting an initial setting diode to a reading circuit of a mechanical switch, and immediately after reading the initial setting input, input of the mechanical switch is performed. Checks for the presence of , disables the read initial setting input when a mechanical switch input is detected, and executes initial setting based on the read initial setting input when a mechanical switch input is not detected. The feature is that a determination means is provided.

Effect: With this configuration, a determination means is provided to determine whether the read initial setting data is valid or invalid between reading the initial setting and executing the initial setting using the read data. You can perform initial settings.

EXAMPLE Hereinafter, an example of the present invention will be explained based on FIGS. 1 and 2. Components having the same functions as those in FIGS. 3 and 4 are designated by the same reference numerals, and their explanations will be omitted.

12 is a microcomputer (for example, M N 1400 manufactured by Matsushita Electronics Co., Ltd.) in which software is fixed in a ROM (read only memory). Second
The figure shows the contents of the ROM, and the initial setting operation will be explained below based on the operation.

First, set outl to “H” level (a-1), and set out2 to “H” level (a-1).
Set it to L” level (a-2) and input from NO to INS to confirm that diode switches 2 and 3 are connected (a-3), but at this time mechanical switch 8
．． If 9 is pressed, it will be mistakenly recognized that a diode switch is connected to outl and INl. Therefore,
Here, the next ICoutlf “L” level [b-1], o
Set ut2 to “HII level (b-2)” and
Mechanical switch input is checked from N3. This check first reads the status of INO to INS (b-3), then checks the contents of (b-3) to determine whether mechanical switches 8 to 11 are turned on (b-4) L/INS. , (b-4) when any of the mechanical switches 8 to 11 is detected to be on, (a-1
) and invalidate the initial setting data read in [a-3]. If the ON state of any of the mechanical switches 8 to 11 is not detected in (b-4), (a −,
Validate the initial setting data read in 3) (
Perform initial settings based on the read contents in a-3) [b-5]. The time required to implement (a-1) to (b-4) is
For example, for M N 14GG, it is about 40 μs, which is extremely short compared to the human response speed and the recovery time of a mechanical switch, so the above operation prevents interference between the diode switch and the mechanical switch without providing a backflow prevention diode as in the past. can.

In the above embodiment, interference between the diode switch and the mechanical switch is prevented by inputting them in a short period of time. Even if input is performed in a relatively long period, interference between the two sides can be prevented.

DETAILED DESCRIPTION OF THE INVENTION As described above, the key input device of the present invention is configured to perform initial setting by connecting an initial setting diode to a reading circuit of a mechanical switch, and to perform initial setting immediately after reading the initial setting input. Determining whether to check for the presence of the mechanical switch, invalidate the read initial setting input when the input of the mechanical switch is detected, and execute the initial setting based on the read initial setting input when the mechanical switch input is not detected. Since the means is provided, it is possible to eliminate the backflow prevention diode required in the conventional key input device. In addition, when the key input device is configured with a microcomputer, the determination means only needs to partially change the software of the microcomputer, and high productivity and cost reduction can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the key input device of the present invention, FIG. 2 is a 70-card diagram of FIG. 1, FIG. 3 is a block diagram of a conventional key input device, and FIG. is a flowchart diagram of FIG. 3; 2.3...Diode switch, 8.9, 10.11
...Mechanical switch, 12...Microcomputer agent Yoshihiro MorimotoFigure 2

Claims (1)

[Claims] 1. Connect an initial setting diode to the reading circuit of the mechanical switch to perform initial setting, and
Immediately after reading the initial setting input, the presence or absence of the mechanical switch input is checked, and when the mechanical switch input is detected, the read initial setting input is invalidated, and when the mechanical switch input is not detected, the read initial setting input is invalidated. A key input device further comprising a determining means for performing initial setting based on the initial setting input.