JPS6142291B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a plurality of vertical lines and horizontal lines are respectively connected via key switches to form a group of key matrix switches, and for example, a vertical line is scanned by a key scan signal and turned on. The key switch that is currently on is determined, and a key input signal corresponding to the key scan signal is obtained from the horizontal line to which the key switch that is turned on is connected.This key input signal is supplied to the receiving circuit, and from there, The present invention relates to a key device capable of obtaining key output signals having a one-to-one correspondence.

By the way, this key device generally provides an output corresponding to each key switch, and if two key switches are pressed at the same time, the output corresponding to the double press by these two key switches cannot be obtained, and the key The device is about to be reset. In other words, double pressing of the key switch is prohibited.

Therefore, operations such as pressing the record switch and play switch at the same time, such as when recording with a video tape recorder, cannot be realized using a key device.

In view of this point, the present invention seeks to provide a novel key device that is capable of double pressing.

Hereinafter, an example of a key device according to the present invention will be explained with reference to the drawings.

In FIG. 1, 1 is a key matrix, which in this example is composed of two horizontal lines and two vertical lines, and therefore has 2×2=4 key switches S ₁ , S ₂ , S ₃ ,
S ₄ is provided.

2 is a receiving circuit, 3 is a signal generating circuit, and the signal generating circuit 3 generates a pulse signal φ whose pulse width sections τ, which are “1”, are shifted so that they do not overlap with each other.
₁ and φ ₂ (FIGS. 2A and B) are obtained. These pulse signals φ ₁ and φ ₂ are supplied to the vertical lines of the key matrix 1 as key scan signals, and are also supplied to the receiving circuit 2 as timing discrimination signals.

T _i1 and T _i2 are key input signal output terminals, and the key input signal K _i1 obtained at these output terminals T _i1 and T _i2
and K _i2 are both in the state of "0" unless the key switch is turned on. and,
For example, when the key switch _S1 is turned on, a signal _φ1 appears on the key input signal K _i1 , which is transmitted to the receiving circuit 2.
The key output signal Ko ₁ is determined to be "1" at the output terminal T ₁ . Also, the key switch
When S ₂ is turned on, a signal φ is applied to the key input signal K _i2.
1 appears, which is determined by the receiving circuit 2,
A key output signal Ko ₂ of "1" is obtained at the output terminal T ₂ . Similarly, when the key switch _S3 is turned on, the signal _φ2 appears in the key input signal K _i1 , and when the key switch _S4 is turned on, the signal _φ2 appears in the key input signal K _i2 , Respectively, when it is detected and the key switch S ₃ is turned on, a key output signal Ko ₃ is sent to the output terminal T ₃ .
However, when the key switch _S4 is turned on, an output signal _Ko4 is obtained at the output terminal _T4 .

In this case, no output is obtained even if two or more of the key switches _S1 to _S4 are pressed at the same time.

That is, for example, when key switches S ₁ and S ₃ are turned on at the same time, the key input signal K _i1 repeats twice as much as the signal φ 1, which is the combination of the signals φ ₁ and φ ₂ , as shown in _FIG . 2C. This becomes a periodic signal, which is detected by the receiving circuit 2. For example, the output circuit of this receiving circuit 2 is reset, and the output terminals T ₁ ,
Output signals _{Ko 1 ,} Ko ₂ , Ko ₃ , and Ko 4 are not obtained at T ₂ , T ₃ , and T ₄ .

Furthermore, when the key switches _S1 and _S2 are turned _on at _the same time, as shown in _FIG . The output circuit of the receiving circuit 2 is reset so that no output signal is obtained at the output terminals T ₁ , T ₂ , T ₃ , and T ₄ .

The above is exactly the same as a conventional key device.

In this invention, key matrix switches S ₁ to _{S 4}
In addition, a switch that can be pressed twice is provided.

That is, in the example shown, the key input signal output terminal T
_i1 and T _i2 are respectively connected via key switches S ₅ and S ₆ to terminal 4 from which a positive DC voltage +E _B is obtained. And each output terminal T _i1 and T _i
The key input signals K _i1 and K _i2 obtained in _{step 2} are supplied to duration detection circuits 5 and 6 which detect the duration of time that the key input signals are "1".

In this case, the duration detection circuits 5 and 6
As shown in Figure C, the key input signals K _i1 and K _i2 are "1" for a time longer than one period t _s of a signal with twice the period of the signal φ ₂₁ which is a composite signal of the signals φ ₁ and φ ₂ . When this is detected, an output signal of "1" is obtained as the output.

Therefore, the key switch of key matrix 1
When S ₁ to _{S 4} are operated, the signal φ ₁ or the signal φ ₂ or a composite signal of both appears in the key input signals K _i 1 and K _{i 2} , so the signal period that becomes “1” is always shorter than t _s Therefore, an output of "1" cannot be obtained from the duration detection circuits 5 and 6.

For example, when the key switch _S5 is turned on, the key input signal K _i1 remains at "1" due to the DC voltage +E _B while the switch _S5 is pressed (Fig. 2 E). The pressing time is usually longer than t _s because t _s is a very short time.

In this case, in the receiving circuit 1, the timing discrimination signals φ ₁ and φ ₂ are used to detect almost the same double pressing of the key switches S ₁ and S ₃ as shown in FIG. It is determined that the pressure is heavy. Therefore, no output signal appears at the output terminals T ₁ , T ₂ , T ₃ , and T ₄ .

On the other hand, the duration detection circuit 5 detects that the time during which the signal K _i1 is "1" is longer than t _s , and its output signal D ₁ becomes "1". At this time, if the key switch _S6 is not pressed, the output signal _D2 of the duration detection circuit 6 is "0", so the output ₂ of the inverter 9 is "1". Therefore, the output of the AND circuit 7 that takes the logical product of the output signal D ₁ and the signal ₂ becomes "1", and the output signal Ko ₅ is sent to the output terminal T ₅ corresponding to the key switch S ₅ .
is obtained.

When only the key switch _S6 is on and the key switch _S5 is off, the output _D2 of the duration detection circuit 6 becomes "1" in the same manner as described above, and at this time the output ₁ of the inverter 10 becomes "1". Therefore, the output of the AND circuit 8 becomes "1", and the output signal Ko ₆ is obtained at the output terminal T ₆ corresponding to the key switch S ₆ .

When both key switches _S5 and _S6 are turned on, the receiving circuit 2 determines that it is a double press and outputs an output signal to the output terminals _T1 , _T2 , _T3 , and _T4.
Ko ₁ , Ko ₂ , Ko ₃ , and Ko ₄ cannot be obtained. At this time, the output signals of the duration detection circuits 5 and 6 are
Since D ₁ and D ₂ both become "1", the outputs of inverters 9 and 10 become "0", and the output terminal
Although the output signals Ko ₅ and Ko ₆ of "1" are not obtained at T ₅ and T ₆ , the output of the AND circuit 11 becomes "1", and the output signal K ₀₅₆ is obtained at the output terminal T ₅₆ .
That is, an output signal _K056 corresponding to a key input when both key switches _S5 and _S6 are turned on is obtained.

As described above, according to the present invention, a key switch can be pressed twice by simply adding a simple circuit to the key device.

Further, the present invention has the advantage that the number of key inputs can be increased without increasing the number of key input signal output terminals or the number of key scan signals.

In the example shown in the figure, the duration detection circuits 5 and 6 detect when the "1" signal persists for a time longer than _ts , but this is because the key scan signals φ ₁ and φ ₂ When the repetition period is short, this is to prevent malfunctions in which the operation is determined to be the operation of switches _S5 and _S6 even though it is an operation of matrix key switches _S1 to _S4.The detection duration is the minimum, It only needs to be larger than the pulse width τ of the signals φ ₁ and φ ₂ .

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an example of a key device according to the present invention, and FIG. 2 is a waveform diagram for explaining the key device. 1 is a key matrix, S ₁ to _{S 4} are its key switches, 2 is a receiving circuit, 3 is a signal generation circuit, 4 is a terminal from which a positive DC voltage can be obtained, 5 and 6 are duration detection circuits, S ₅ and S ₆ is another switch.

Claims (1)

[Claims] 1. The key input signal output terminal is connected to a terminal from which DC voltage is obtained via a key switch different from the key matrix switch to which the pulse-shaped key scan signal is supplied, and the key input signal output terminal is connected to the key input signal output terminal for a predetermined period or more. A key device equipped with a detection circuit that detects a DC signal that maintains one state and obtains an output signal.