JP3199805B2 - Key input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a key input device input devices are connected to each of the two pairs of signal line groups constituting the matrix circuit.

[0002]

2. Description of the Related Art In a device such as a keyboard which requires a large number of key switches to be provided, when each of the key switches is connected to an input element, the number of wires increases and the number of key switches increases. Therefore, a configuration in which a key switch is connected to each intersection of the matrix circuit is adopted as shown in FIG. 4, and one of two signal line groups constituting the matrix circuit is used. Output elements 91 to 94 are provided for each of the signal line groups X91 to X94.
And input elements 81 to 84 are connected to the other signal line groups Y91 to Y94, respectively.

Each of the output elements 91 to 94 is sequentially set to L level in the order from the output element 91 to the output element 94 (indicated by L91 to L94 in FIG. 5). Each time the L level moves, a signal transmitted from the input elements 81 to 84 is read (the timing of this reading is indicated by T91 to T94).

In the above operation, the key switches S91, S9
Assuming that 2 is pressed, the signal line Y92 goes low at the timing T92, and the signal line Y93 goes low at the timing T94. In other combinations, the signal lines Y91 to Y94 are all at H level, so that it is identified that the key switches S91 and S92 are pressed.

[0005]

When the above circuit configuration is applied to a device having an extremely large number of key switches, for example, the number of key switches of the device is 160 and the number of input circuits is 1 byte. Assuming that only the eight circuits can be used, the number of output signal lines connected to the matrix circuit is twenty. Therefore, to read the state of all key switches,
Since it is necessary to read the state of the input signal line while sequentially setting the output signal lines of the 20 circuits to the L level for each signal line, it takes time to read the state of the key switch. A problem of cost.

The present invention has been conceived in order to solve the above-mentioned problem, and an object of the present invention is to provide a key input device capable of shortening a reading time of a state of a key switch.

[0007]

A key input device according to the present invention.
Is the X signal line group (X ₁ , X ₂ ... X _j ... X _N : j = 1 ≦ p, q, r,
s, t, u ... ≦ N) and Y signal line group (Y ₁ , Y ₂ ... Y _j ... Y _N )
Matrix circuit with key switch connected at each intersection with
And each pin of the X signal line group and the Y signal line group
Key switch to which a pull-up resistor and input / output element are connected
Switch the input / output state of the matrix circuit and the input / output element
To the X signal line group or the Y signal line group.
A signal is output via a writing output element, and a Y signal line
The signals appearing on each line of the group or the X signal line group are
Input through the key to identify the keyswitch that was pressed.
And an output circuit, wherein the input / output circuit outputs an X signal.
The L signal is output to the line group, and the signal of the Y signal line group at this time is output.
Input, and recognize the signal lines on which the L signal has appeared and the number thereof,
As a result, when the L signal appears on one signal line Yp
Outputs the L signal to the Y signal line group, and outputs the X signal line at this time.
The number of signal lines and the number of signal lines on which L signals appeared when a group signal was input
As a result, an L signal appears on one signal line Xq.
When the signal line Xp corresponds to the intersection of the signal line Xq and the signal line Yp.
And that two or more signal lines
When an L signal appears on Xr, Xs,.
Keith corresponding to each intersection of r, Xs... and signal line Yp
While the switch is identified as being pressed, two or more signal lines Y
When an L signal appears at p, Yq...
Output L signal and input signal of X signal line group at this time
And recognizes the signal lines on which the L signal has appeared and the number thereof, and
As a result, when the L signal appears on one signal line Xr, the signal
Key corresponding to the intersection between the signal line Xr and the signal lines Yp, Yq.
-Switch is pressed and two or more signal lines X
When an L signal appears at r, Xs,.
X signal is sequentially output for each line to Xs.
Signals of the Y signal line group are sequentially input, and an L signal appears.
The signal lines are recognized, and as a result, one or more signal lines Yt, Yt
When the L signal appears at u ···, the signal lines Xr, Xs ·
· And the Keith corresponding to each intersection of the signal lines Yt, Yu
Note that the switch is configured to be identified as pressed.
It is a sign.

[0008]

By driving the input / output elements, all the X signal line groups are set to the L level, and in this state, the Y signal line groups are read by the input / output elements. After that, all of the Y signal line groups are set to the L level using the input / output elements, and in this state, the input / output elements read the X signal line groups.

If the number of simultaneously input key switches is limited to two, as a result of the above operation,
In each signal line group of the X signal line group and the Y signal line group, if an L level appears on only one signal line, a key switch connected to the intersection of the signal lines where the L level appears appears. Is identified.

In one signal line group, two signal lines have L
When a level appears and an L level appears on one signal line in the other signal line group, a key switch connected to two intersections formed by the signal lines on which the L level appears appears. Is identified.

In the case where the L level appears on two signal lines in both signal line groups, four intersections formed by these signal lines are candidates, and two pairs having a diagonal positional relationship with each other are set. Either of the combinations of the intersections is an intersection indicating the pressed key switch. Therefore, the signal line belongs to one signal line group and L
Of the two signal lines in which the level has appeared, one signal line transmits an H level and the other signal line transmits an L level. In this state, the state of the other signal line group is read. , Is identified from the above two combinations.

[0012]

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

FIG. 1 is a circuit diagram showing the electrical connection of one embodiment of the key input device according to the present invention. In the figure, in order to make the description easy to understand, the configuration of the matrix circuit is 4 × 4 and the configuration includes 16 key switches, but the practical device has a configuration including a large number of key switches. Has become.

In FIG. 1, input terminals of buffers Xi11-Xi14 and output terminals of buffers Xo11-Xo14 are connected to four signal lines X11-X14, respectively, and a signal line Y1
Input terminals of buffers Yi11 to Yi14 and output terminals of buffers Yo11 to Yo14 are connected to each of 1 to Y14.

Note that all the buffers Xi11 to Xi14, Xo
11 to Xo14, Yi11 to Yi14, and Yo11 to Yo14 have three outputs, and buffers Xi11 to Xi14 and Xo11 to Xo1
4. The output control terminals of Yi11 to Yi14 and Yo11 to Yo14 are connected to each other for each group.

The output terminals of the buffers Xi11 to Xi14 are connected to the respective input terminals of the buffers Xo11 to Xo14, and the output terminals of the buffers Yi11 to Yi14 are connected to the respective input terminals of the buffers Yo11 to Yo14. Have been. The signal lines X11 to X14 and the signal lines Y11 to Y14 are all pulled up by the resistor R, and the key switches SW11 to X14 are provided at the respective intersections of the signal lines X11 to X14 and the signal lines Y11 to Y14. SW44 is connected.

The signal lines X21 to X24 connected to the respective input terminals of the buffers Xo11 to Xo14 and the buffer Yo11
~ Signal line Y21 connected to each input terminal of Yo14 ~
Y24 is an input / output circuit provided externally for each
(Although not shown, the flow chart shown in FIG. 2 is used here.
Is connected to a microcomputer) for processing over bets, the signal lines output control terminal is connected to the buffer Xi11~Xi14 XiEN, signal line output control terminal is connected to the buffer Xo11~Xo14 XoEN, buffer Yi11~ Signal line YiEN to which output control terminal of Yi14 is connected, buffer Yo
Signal line Yo to which output control terminals of 11 to Yo14 are connected
Each EN is led to the input / output circuit .

In the above configuration, the X signal line group 11 is constituted by four signal lines X11 to X14, and the Y signal line group 12 is similarly constituted by four signal lines Y11 to Y14. Further, the input data of the key switches SW11 to SW44 in the present embodiment are obtained when only one key switch is pressed or when two key switches are pressed simultaneously.
It is configured to output data corresponding to the pressed key switches S11 to S44.

Each of the input / output elements described in claim 1 has a pair of buffers (for example, a combination of Xo11 and Xi11;
Or a combination of Yo11 and Yi11).

FIG. 2 is a flowchart showing the operation of identifying the key switches SW11 to SW44 pressed in the above embodiment.
FIG. 3 is an explanatory diagram for capturing the description of the flowchart shown in FIG. Referring to the same figure as necessary, one embodiment of the present invention whose configuration has been described above,
The operation will be described below.

Buffers Xi11-Xi14, Xo11-Xo14, Yi11-
All of Yi14 and Yo11 to Yo14 use an element whose output becomes active when an H level is applied to its output control terminal and a high impedance when an L level is applied to the output control terminal. By setting the signal lines XoEN and YiEN to H level and setting the signal lines XiEN and YoEN to L level, the X signal line group 11 is output.
The signal line group 12 is set as an input (step S11).

Now that two key switches have been pressed, Y
It is assumed that the L level is detected on two signal lines of the signal line group 12. It is assumed that the signal lines at which the L level is detected are the signal lines 41 and 42 in FIG.

Then, by setting the signal lines XoEN and YiEN to L level and setting the signal lines XiEN and YoEN to H level, the X signal line group 11 is input and the Y signal line group 12 is output.
(Steps S12 and S17). At this time, of the X signal line group 11,
It is assumed that the signal lines at which the L level is detected are 43 and 44 shown in FIG.

As described above, in the present embodiment, the number of key switches to be pressed is limited to two, so that the signal lines 41 to 44 are at the L level because the key switch SW51 and the key switch Either when SW54 is pressed or when SW52 and SW53 are pressed.

Therefore, in order to identify which combination of these two key switches is the combination of the key switches actually pressed, the signal line 41 is set to the H level and the signal line 42 is set to the L level. In the state, the signal lines 43 and 44 are read (steps S18 and S19).

When the read signal line 43 is at the H level and the signal line 44 is at the L level, it means that the key switches SW51 and SW54 are being pressed. Assuming SW54 is pressed,
The corresponding data is transmitted. The signal line 43 is L
Key switch when the signal line 44 is at H level
Since SW52 and SW53 are pressed, data corresponding thereto is output (step S20).

In the operation of step S11, the signal line
When the L level is detected at 41 and 42 and the L level is detected only at the signal line 43 in the operation of step S17,
Since this means that the key switches SW51 and SW52 have been pressed, data is output in accordance with the state (steps S11, S12, S17, S18, S21).

In the operation of step S11, the signal line 41
If the L level is detected on the signal lines 43 and 44 in the operation of step S13, it means that the key switches SW51 and SW53 are being pressed. Output
(Steps S11, S12, S13, S14, S16).

When only one key switch is pressed, the L level is always output to only one signal line in each operation of steps S11 and S17. Since the key switch connected to the intersection of is pressed, the data corresponding to the key switch is output (steps S11, S12, S13, S14, S1
Five).

The above operation described with reference to FIG. 3 will be described again with reference to FIG. 1. In step S11, the signal line
Y11 L level is only detected, when the L level is detected only in the signal line X12 in step S13, this means that the key switch SW 12 is pressed, step S1
When the L level is detected only on the signal line Y12 in 1 and the L level is detected on the signal lines X12 and X13 in step S13, it means that the key switches SW22 and SW23 have been pressed.

In step S11, the signal lines Y12, Y1
4 L level is detected, the signal line in step S17
When the L level is detected only at X14, it means that the key switches SW24 and SW44 are pressed.

In step S11, the signal lines Y13, Y1
4 L level is detected, the signal line in step S17
When the L level is detected at X13 and X14, it means that the combination of the key switches SW33 and SW44 has been pressed or the combination of the key switches SW43 and SW34 has been pressed. The signal line Y13 is set at the L level, and the signal line Y14 is set at the H level. In this state, the levels of the signal lines X13 and X14 are read), and which of the combinations is identified.

The present invention is not limited to the above embodiment. Regarding the number of key switches, the case where the configuration is such that two key switches are identified at the same time has been described. However, as other numbers, for example, three, four, or five key switches are simultaneously pressed. In this case, the present invention can be similarly applied to a configuration in which the pressed key switch is identified.

[0034]

According to the key input device of the present invention ,
A key switch is connected to each intersection of the X signal line group and the Y signal line group.
Having a matrix circuit connected thereto and a group of X signal lines;
Pull-up resistor and I / O element on each line of
A connected key switch matrix circuit and the input / output
Switching the input / output state of the element, the X signal line group or
Outputs a signal to each line of the Y signal line group through the input / output element.
At this time, appearing on each line of the Y signal line group or the X signal line group.
Input signal through the input / output element, and press the pressed key.
-An input / output circuit that identifies the switch
Therefore, the number of times of reading the signal of the signal line group to identify the pressed key switch is constant regardless of the number of signal lines of the signal line group constituting the matrix circuit. Can be shortened. Moreover, multiple key switches can be used simultaneously
Key switch, the key switch is identified.
Key switch
It is possible to input more data at once than the number of
That there is no need to increase the number of key switches
Cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an electrical connection of an embodiment of a key input device according to the present invention.

FIG. 2 is a flowchart showing an operation of identifying a pressed key switch in the embodiment shown in FIG. 1;

FIG. 3 is an explanatory diagram for capturing the description of the flowchart shown in FIG. 2;

FIG. 4 is a circuit diagram showing a conventional electrical connection.

FIG. 5 is a timing chart showing the timing of reading a key switch according to the related art.

[Explanation of symbols]

 11 X signal line group 12 Y signal line group

Claims (1)

(57) [Claims] 1. An X signal line group (X ₁ , X ₂ ... X _j ... X _N : j =
1 ≦ p, q, r, s, t, u ... ≦ N) and the Y signal line group _{(Y 1, Y 2 ·· Y} j
・ ・ A mat with a key switch connected at each intersection with Y _N )
X signal line group and Y signal line group having a risk circuit
Key with pull-up resistor and I / O element connected to each line
-Switch matrix circuit and input / output of the input / output element
The state is switched, and the X signal line group or the Y signal line group
A signal is output to each of the lines via the input / output element, and
Signal appearing on each line of the Y signal line group or the X signal line group
Input via the input / output element and press the pressed key switch.
An input / output circuit for identifying, the input / output circuit outputs an L signal to an X signal line group,
The signal of the Y signal line group at the time
Signal lines and their numbers, and as a result, one signal line Yp
Output the L signal to the Y signal line group when the L signal appears at
Then, the signal of the X signal line group at this time is input, and the L signal is
Recognized signal lines and their number, and as a result,
When the L signal appears on the signal line Xq, the signal line Xq and the signal
It is recognized that the key switch corresponding to the intersection with the line Yp has been pressed.
Separately, an L signal appears on two or more signal lines Xr, Xs.
, The signal lines Xr, Xs,.
One that identifies that the key switch corresponding to the intersection has been pressed
On the other hand, if an L signal appears on two or more signal lines Yp, Yq.
At this time, the L signal is output to the signal line, and the X signal at this time is output.
A signal line in which a signal of a line group is input and an L signal appears and the signal line
As a result, the L signal is present on one signal line Xr.
The signal line Xr and the signal lines Yp, Yq.
Identifies that the key switch corresponding to the intersection has been pressed, and
When the L signal appears on the signal lines Xr, Xs,.
Outputs the L signal sequentially to the signal lines Xr, Xs,.
Then, the signals of the Y signal line group in this process are sequentially input and
Recognize the signal line on which the L signal appeared, and as a result,
When the L signal appears on the signal lines Yt, Yu,.
Intersections between signal lines Xr, Xs,... And signal lines Yt, Yu,.
Is configured to identify that the key switch corresponding to
A key input device characterized in that: