JPH06101266B2 - ON / OFF key switch malfunction prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is a device for processing inputs from a plurality of key switches by using a microcomputer. The present invention relates to a device that prevents malfunction when pressed.

[Outline of Invention]

When there is a key input from the on / off key switch, the manual chatter timer is activated, and when the same key input is made during that operation, the subsequent key input is disabled and the on / off key switch is continuously pressed. This is to prevent malfunction in the case of doing.

[Conventional technology]

Conventionally, in the case of using a microcomputer to fetch the key of the key switch, as shown in the flowchart of FIG. 3, when there is a key input, it is input again within a fixed time (about 30 ms). Even if there is one, it counts one input to prevent malfunction due to mechanical chattering of the switch.

However, in the chattering of the key switch, in addition to the mechanical chattering that generally occurs at the time of operation, there is manual chattering that occurs due to a bad pressing of the key switch. For example, when the key switch is operated in a disorderly manner or when the key switch is operated in a vibrating traveling vehicle, the operator may have intended to press once but actually pressed twice in succession. Such continuous key presses usually occur after a much longer time than mechanical chattering (occurring within 30 ms).

In the case of the on / off key switch, unlike the shift key, there is no need to press the same key switch twice in succession, but in the above-mentioned conventional device, the on / off key switch is pressed continuously. Even in the case of inputting, there is a drawback that the operation intended by the operator is not performed because the key acquisition is performed twice.

[Problems to be solved by the invention]

An object of the present invention is to improve the drawbacks of the above conventional device, and to provide a malfunction prevention device for an on / off key switch, which prevents malfunction when the on / off key switch is accidentally continuously pressed. .

[Means for solving problems]

In order to achieve the above object, the malfunction prevention device for an on / off key switch according to the present invention includes a plurality of key switches including at least one on / off key switch, and when the key input is made, it is turned on / off. A means for determining whether or not it is by an off key switch, a manual chatter timer that is set and operates for a certain time when the key input is determined to be by an on / off key switch, and during the operation of the manual chatter timer. And a means for invalidating the subsequent key input when the same key input is made.

[Action]

By doing this, even if the same key input is made again within the operation time of the manual chatter timer after the key input is made by the ON / OFF key switch, the subsequent key input will be invalid. Malfunction due to is prevented.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a key matrix circuit diagram connected to a microcomputer, and FIG. 2 is a processing flowchart at the time of key input.

At a first figure of the respective intersections of the output ports O ₁ ~ O ₃ and the input port I ₁ ~I ₃ key switch S ₁ to S ₉ microcomputer 1 is connected, the output port O ₁ ~ O ₃ The key switches S _{1 to} S ₉ depend on the levels of the input ports I _{1 to} I ₃ when they are sequentially set to the H level.
It is designed to detect that any one of the buttons has been pressed.

Each of the key switches S _{1 to} S ₉ corresponds to a selection operation of, for example, a tape, a tuner, a player or the like, and when any one of them is pressed, the key processing as shown in FIG. 2 is performed in the microcomputer 1. Then, the operation signal is output from the control output ports O _{4 to} O ₁₀ .

Microcomputer 1 has a previous key buffer as RAM and a manual chatter timer with an operating time of about 300 ms. If there is a key input, after confirming that mechanical chattering is eliminated and there is no double press, that key input Is determined by the ON / OFF key switch, and when determined as NO, a control signal corresponding to the key input is created and output to the control output ports O _{4 to} O ₁₀ .

Also, when it is determined that it is due to the on / off key switch, after inputting this key input to the key buffer last time and setting the manual chatter timer,
A control signal corresponding to the key input is created and output to control output ports O _{4 to} O ₁₀ .

When there is a key input during the operation of the manual chatter timer, the stored contents of the key buffer are referred to last time, and if the current key input is the same as the previous one, the current key input is invalidated. Since the manual chatter timer operation time is set to 300 ms, which is sufficiently longer than the time when manual chattering occurs, this also eliminates manual chattering that occurs after mechanical chattering. If it is different from the previous key input, a control signal corresponding to the key input is created and output to the control output ports O _{4 to} O ₁₀ .

In the above embodiment, the operation time of the manual chatter timer is set to about 300 ms, but 100 to 400 ms
Within the range, it is sufficiently practical.

〔The invention's effect〕

As described above, the malfunction prevention device for an on / off key switch according to the present invention can surely prevent malfunctions caused by continuous accidental pressing, and if used in an audio device or the like, its operability is significantly improved. It can be done.

[Brief description of drawings]

FIG. 1 ... Key matrix circuit diagram of an embodiment of the present invention FIG. 2 ... Processing flow chart for key input thereof FIG. 3 ... Processing flow chart for key input of conventional device 1 ... Microcomputer I _{1 to} I ₃ ... Input Ports O _{1 to} O ₃ …… Output ports O _{4 to} O ₁₀ …… Control output ports S _{1 to} S ₉ …… Key switch

Claims (1)

[Claims] (A) A plurality of key switches including at least one on / off key switch; and (b) when a key input is made, it is determined whether or not the key switch is an on / off key switch. And (c) a manual chatter timer that has an operating time longer than the time that manual chattering occurs and is set when it is determined that the key input is an on / off key switch, and (d) a manual chatter timer. An on / off key switch malfunction prevention device, comprising means for invalidating a subsequent key input when the same key input is made during the operation of the timer.