JP2589707B2 - Keyboard device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a keyboard device used as an input device in various OA devices such as a word processor and a personal computer.

2. Description of the Related Art A configuration of a conventional keyboard device will be described below.

FIG. 3 is a configuration diagram of a conventional keyboard device, wherein 1 is a control unit disposed in the device main body, 2 is a cable connecting the control unit 1 of the device main body and the keyboard device, and A is a keyboard device and is shifted. A key switch 4a corresponding to each key (not shown) on the keyboard is disposed at each intersection of the key matrix 4 and a register 3 and a key matrix 4. (However, not shown except for three key switches in FIG. 3) The operation of the keyboard device configured as described above will be described below with reference to a time chart shown in FIG.

First, the control unit 1 on the main unit side transmits a strobe signal (hereinafter, STB
) Is set to “L”, and a read operation is performed once. This read operation activates the read strobe signal RD, and the shift register 3 performs a shift operation at the fall of the read strobe signal RD. The control unit 1 reads the data D0 to D7 at the rise of the read strobe signal RD. As a result, at the time of the first read operation, the output Q1 of the shift register 3 becomes “L”, and the input data of the control unit becomes Q1.
If any one of the key switches connected to is pressed, the bit becomes "L". Next, at the time of the second read operation, the read operation is performed by setting the strobe signal STB to “H”. Therefore, at the time of the second read operation, the output Q2 of the shift register 3 becomes "L", and the bit of the control unit input data becomes "L" when the key switch connected to Q2 is pressed. Thereafter, similarly, the control unit 1 performs the read operation for all the key switches constituting the key matrix 4.

Problems to be Solved by the Invention However, the above-mentioned conventional configuration uses a key matrix composed of 8N key switches (N is an integer) and an N-stage shift register, and the signal lines are D0 to D0.
D7, read strobe signal RD, strobe signal STB
A total of 10 are required. Therefore, the number of input / output terminals of the control unit 1 is occupied by the number corresponding to the number, that is, 10 terminals.
There is a problem that the number of terminals for controlling other circuits is reduced. In addition, since the number of signal lines is large, a connector having a large number of terminals is required, which leads to an increase in cost. Still further, when the number of signal lines is simply reduced in the above-described conventional keyboard device, there is a problem that the number of stages of the shift register increases and the circuit scale increases as shown in FIG. That is, if the number of data lines is reduced to 1 / N, 4N shift registers are required.

Means for Solving the Problems In order to solve the above problems, the present invention provides a frequency dividing circuit which receives a clock signal from a control unit and divides the frequency, and receives a frequency division output from the frequency dividing circuit. A shift register for selectively turning on a plurality of output lines in accordance with the input clock in accordance with the input clock; the plurality of input terminals are divided into two groups; and data input to the first group of input terminals are output. A second output terminal for outputting data to be input to a first output terminal and a second group of input terminals, and the data of each input terminal in both groups are simultaneously converted into a serial format in accordance with the frequency division output from the frequency division circuit. A data selector for converting and outputting the data from the first and second output terminals, respectively.

Operation According to the above configuration, the read operation is performed by dividing the data of an example of the key matrix by the same number of times as the frequency division ratio of the frequency divider circuit, so that the signal for connection with the control unit of the main body without increasing the number of shift register stages. Can reduce the number of lines,
In addition, the data selector has two output terminals, and each output terminal simultaneously outputs the data of the input terminal of the corresponding group according to the output of the frequency dividing circuit, so that the time for one cycle of key reading can be shortened. The ON / OFF information of the two contacts can be output at the same time.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of a keyboard device according to one embodiment of the present invention.

In FIG. 1, reference numeral 11 denotes a control unit arranged in the device body,
Reference numeral 12 denotes a cable for connecting the control unit 11 in the device body to the keyboard device, and B denotes a keyboard device, which is a shift register.
13, a key matrix 14, a frequency dividing circuit 15 for performing frequency division, and a data selector 16 are incorporated.

Reference numeral 14a denotes a key switch connected to each intersection of the key matrix 14 (however, not shown in FIG. 1 except for three key switches).

The operation of the keyboard device of this embodiment configured as described above will be described below with reference to the time chart shown in FIG.

First, the frequency dividing circuit 15 divides the clock CK input by four,
As shown in the figure, outputs 01 to 04 having different phases are generated. The shift resist 13 clocks one of the plurality of outputs from the frequency divider circuit output 01 (output 01 in this embodiment).
CK is input, and the shift operation is performed at this falling edge. In addition, the data selector 16 sets any one of A1 to A4 as the output Aout and Bout by the control inputs S1 to S4,
Any one of 1 to B4 is output. First, the controller 11 sets the strobe signal STB to "L" and performs the first read operation. This read operation causes the read strobe signal
RD becomes active, the frequency divider 15 operates at the falling edge of the read strobe signal RD, and the output 01 becomes "L". At this time, 02, 03, and 04 of the outputs of the frequency dividing circuit 15 remain "H". Due to this operation, the output of the shift register 13 becomes "L" for only Q1, and the outputs SD0 to SD7 output the 1 of the key matrix.
The pressing status of the key switch in the column is output. Since only S1 of the control inputs S1 to S4 is "L", the data selector 16 outputs Al, that is, SD7 to the output Aout, and outputs the output Bout
B6, that is, SD6. Therefore, the control unit 11 reads these data from the D7 and D6 terminals at the rise of the read strobe signal RD. Next, after the second read operation, the operation is performed with the strobe signal STB set to "H". At the time of the second read operation, the output of the frequency divider circuit becomes "L" only at 02 at the fall of the read strobe signal RD, and the state of the shift register 3 is the same as the first time.
A2 output, that is, SD5 is output to Aout, and B2, that is, SD4 is output to Bout, and the control unit 11 reads these data from the D7 and D6 terminals. Similarly, the control unit 11 reads SD1 and SD0 in the third read operation. The reading of the data in the first column of the key matrix 14 is completed by these four reading operations. And 5-8
In the second read operation, the output of the frequency divider 15 returns to the same state as in the first to fourth read operations.
Is output from the key matrix 14 because only the output Q2 becomes "L" since the output 01 of the frequency divider 15 is used as the clock CK.
The state of depression of the key switch in the second column is output to SD7 to SD0. Therefore, the read data of the control unit 11 is SD7, SD6 in the fifth read operation, SD5, SD4 in the sixth read operation, SD3, SD2 in the seventh read operation, and SD1, SD0 in the eighth read operation. As described above, the data of each column of the key matrix 14 is read by four read operations, and the pressed states of all the key switches constituting the key matrix are read by 4N read operations.

As described above, according to the present embodiment, the data of one column of the key matrix is divided into the same number of times as the frequency division ratio of the frequency dividing circuit and the read operation is performed via the data selector, thereby reducing the number of stages of the shift register. The signal between the main body controller and the keyboard device can be reduced without increasing the number of signals.

According to the present invention, a shift circuit is provided by providing a frequency dividing circuit for inputting and dividing a read strobe signal from the main body side control unit and a data selector for selecting a data output by an output of the frequency dividing circuit. The number of signal lines of the connection cable between the main body control unit and the keyboard device can be reduced without increasing the number of register stages, and the data selector has two output terminals, each output terminal of each corresponding group. Since the data of the input terminal is output simultaneously from both groups according to the output of the frequency dividing circuit, the time for one cycle of key reading can be shortened, and the detection of ON / OFF information is delayed even if a person having quick key input capability uses the data. Without any discomfort, and at the same time turning on two contacts,
Since the OFF information is output, there is an effect that the detection delay hardly occurs even when characters are input by simultaneously pressing two keys.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a connection state between a keyboard device and a control unit on the main body side in one embodiment of the present invention, FIG. 2 is a time chart showing operation of the keyboard device in the embodiment, FIGS. FIG. 5 is a circuit diagram showing a connection state between a conventional keyboard device and a control unit on the main body side, and FIG. 4 is a time chart showing an operation of the keyboard of the conventional example. 11 Control unit on main unit 12 Cable 13 Shift register 14 Key matrix 14a Key switch 15 Frequency divider 16 Data selector

Claims (1)

(57) [Claims] A frequency dividing circuit for dividing a frequency by inputting a clock signal from a control unit; a frequency divided output from the frequency dividing circuit being used as an input clock; A shift register to be turned on; a plurality of input terminals divided into two groups; a first output terminal for outputting data to be input to an input terminal of a first group; and a data to be input to an input terminal of a second group. A data output selector for converting data of each input terminal into a serial format simultaneously for both groups according to the frequency division output from the frequency division circuit, and outputting the data from the first and second output terminals, respectively. And a key switch connected in a matrix between a plurality of output lines of the shift register and a plurality of input lines of the data selector. Board device.