JP2005063195A - Keyboard - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a keyboard in which a processor reads input data at a moment a key cell is pressed and at a moment it is released in order to solve various problems in traditional arts. <P>SOLUTION: The keyboard comprises a key module having at least one key cell having an output end electrically connectable to a first voltage or a second voltage; a detection circuit electrically connected to the output terminal of the key cell, which generates a control signal CS every time the voltage at the output end of the key cell is switched from the first voltage to the second voltage or from the second voltage to the first voltage; a parallel/serial register electrically connected to the output terminal of the key cell; and the processor electrically connected to the parallel/serial register, which controls the operation of the parallel/serial register according to the control signal CS. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a keyboard, and more particularly to a keyboard that allows a processor to read input data when a key cell is pressed and released.

Please refer to FIG. FIG. 1 is a block diagram of a conventional keyboard 10. The keyboard 10 includes a matrix key module 12 and a processor 14 connected to the matrix key module 12. The matrix key module 12 includes a plurality of key cells arranged in a matrix manner, and the processor 14 reads input signals from the output terminals B _{0 to} B ₇ of the key cells in the matrix key module 12 in a polling manner.

The disadvantage of the prior art is that whenever any key cell of the matrix key module 12 is pressed, the processor 14 continuously receives the input signals at the key cell outputs B ₀ -B _{7 in} the matrix key module 12 as keys. Polling until the cell is removed to reduce the functionality of the processor 14;

  In order to solve the above-described problems, an object of the present invention is to provide a keyboard that allows a processor to read input data when a key cell is pressed and when it is released.

  The present invention provides a keyboard. The keyboard includes a key module having at least one key cell whose output end can be selectively electrically connected to the first voltage or the second voltage, and electrically connected to the output end of the key cell. A sensing circuit for generating a control signal each time the voltage at the output of the key cell is switched from the first voltage to the second voltage or from the second voltage to the first voltage; and electrically connected to the output of the key cell A parallel / serial register connected; and a processor electrically connected to the parallel / serial register and controlling the operation of the parallel / serial register by a control signal.

The keyboard according to the present invention includes a key module, a detection circuit, a parallel / serial register, and a processor. The detection circuit detects a change between a current input signal input by the key module and a previous input signal. In other words, the detection circuit can detect which key cell of the key module is pressed or removed. The processor inputs the current input signal only when there is a change in the input signal. Thus, the keyboard according to the present invention can improve the function of the processor by improving the disadvantage of the prior art that it has to be continuously polled every time any key cell is pressed.
In order to describe the characteristics of such a keyboard in detail, a specific example will be given and described below with reference to the drawings.

  The keyboard according to the present invention controls the processor to output the key cell of the key module from the parallel / serial register through a control signal generated by the voltage generated in the capacitor at the moment when the key cell in the key module is pressed or released. The input signal at the end is input.

Please refer to FIG. FIG. 2 is a block diagram of a keyboard 50 according to the present invention. The keyboard 50 includes a key module 52 including at least one key cell (for example, the key cells 60 and 61 in FIG. 2), and the output terminals OUT ₆₀ and OUT ₆₁ of the key cells 60 and 61 of the key module 52 and the electrical circuit. Detection circuit 54 electrically connected, parallel / serial register 56 electrically connected to output terminals OUT ₆₀ and OUT _{61 of} key cells 60 and _61, and parallel / serial register 56 and detection circuit 54 are electrically connected. The parallel / serial register 56 includes a processor 58 for controlling the reading of the input signal of the output terminals OUT ₆₀ and OUT ₆₁ of the key cells 60 and 61 through the control signal CS from the detection circuit 54.

The key cells 60 and 61 of the key module 52 include switches SW ₆₀ and SW ₆₁ , respectively. Output terminal _{OUT 60} of the key cell 60 (or the output terminal _{OUT 61} of the key cell 61) the switch _{SW 60} (or the switch _{SW 61)} electrically connected to the first voltage _{V CC} or second voltage GND, respectively by opening and closing the Is done. In other words, when the key cell 60 is pressed, the switch SW ₆₀ is turned off, and the output terminal OUT ₆₀ is electrically connected to the second voltage GND to output the logic low voltage _VL . Conversely, if the key cell 60 is disconnected, the switch _{SW 60} is turned on, the output terminal _{OUT 60} outputs a logic high voltage _{V H} is electrically connected to the first voltage _{V CC.} A logic high signal or a logic low signal at the output terminals OUT ₆₀ and OUT ₆₁ corresponds to an input signal.

The detection circuit 54 includes at least one capacitor corresponding to the key cell of the key module 52 (for example, the capacitors 64 and 65 respectively corresponding to the key cells 60 and 61 of the key module 52 in FIG. 2), the capacitor 64, An amplifier 66 that is electrically connected to 65 and amplifies the voltage in the capacitors 64 and 65, and a voltage that is electrically connected to the amplifier 66 and is output from the output terminal OUT _amp of the amplifier 66 is within a predetermined range. Two comparators 68 and 70 for outputting control signals respectively, and an OR gate 72 electrically connected to the output terminals of the comparators 68 and 70.

At the moment when the key cell 60 (or key cell 61) of the key module 52 is pressed or removed, the switch SW ₆₀ of the key cell ₆₀ is turned off or turned on accordingly, or the output OUT ₆₀ It is switched accordingly to the second voltage GND or a first voltage V _CC. At that moment, the sensing circuit 54 senses a transient voltage V _{ts of} 100-150 mV occurring at the capacitor 64 (or capacitor 65). Please refer to FIG. FIG. 3 is a waveform diagram of the transient voltage V _ts and the control signal CS at the capacitors 64 and 65 detected by the detection circuit 54 at the moment when the key cells 60 and 61 of the keyboard 50 according to the present invention are pressed or removed. According to FIG. 3, at the moment when the key cell 60 (or key cell 61) is pressed at time t ₁ (or time t ₂ ), the switch SW ₆₀ of the key cell ₆₀ is turned off and the output terminal OUT ₆₀ is It is switched to the second voltage GND (that is, the input signal at the output terminal OUT ₆₀ of the key cell 60 becomes the logic low voltage V _L ). In this case, the detection circuit 54 detects the negative transient voltage V _ts− generated in the capacitor 64. Conversely, at the moment when the key cell 60 (or key cell 61) is removed at time t ₃ (or time t ₄ ), the switch SW ₆₀ of the key cell ₆₀ is turned on, and the output terminal OUT ₆₀ is the first. The voltage is switched to _VCC (ie, the input signal at the output terminal OUT ₆₀ of the key cell 60 becomes the logic high voltage V _H ). In this case, the detection circuit 54 detects the positive transient voltage V _{ts +} generated in the capacitor 64. The amplifier 66 amplifies the positive transient voltage V _{ts +} and the negative transient voltage V _ts− in the capacitors 64 and 65, and the amplified positive transient voltage V _{ts ++} and the negative transient voltage V _ts− are input to the comparators 68 and 70, respectively. To enter. In the present invention, the comparators 68 and 70 are divided into a positive comparator 68 and a negative comparator 70. The detection circuit 54 is configured such that the amplified positive transient voltage V _{ts +} exceeds the positive reference voltage V _{ref ++} at the other input terminal of the positive comparator 68, or the amplified negative transient voltage V _ts− is the other of the negative comparator 70. A control signal is output from the output terminal OUT _or of the OR gate 72 when the negative reference voltage V _ref− at the input terminal is lower than the negative reference voltage V _ref− .

After receiving the control signal CS, the processor 58 controls the parallel / serial register 56 to input the input signals at the output terminals of all the key cells of the key module 52 in parallel, and then inputs the input signals in serial. Let them input one by one. For example, at time t ₁ when the control signal CS is received, the processor 58 controls the parallel / serial register 56 to input data (01) at the output terminals OUT ₆₀ and OUT ₆₁ of the key cells 60 and 61 in parallel. After inputting, the input signal (01) is read in a serial manner. Further, for example, at time t ₂ , t ₃ , t ₄ , the processor 58 controls the parallel / serial register 56 to input the input data (00), (10), (11) in parallel, and then serially The input signals (00), (10), and (11) are read by the method. The processor 58 operates on input signals or changes in input signals. The operation is based on the conventional technique, and the description thereof is omitted here.

  The above is a preferred embodiment of the present invention and does not limit the scope of the present invention. Therefore, any modifications or changes that can be made by those skilled in the art, which are made within the spirit of the present invention and have an equivalent effect on the present invention, shall belong to the scope of the claims of the present invention. To do.

  The keyboard according to the invention reads the input signal at the output of the key cell only at the moment when any key cell of the key module is pressed or removed. Thus, the present invention saves time for the processor to read the input signal input to the key module and improves the function of the processor.

It is a block diagram of the conventional keyboard. It is a block diagram of the keyboard by this invention. FIG. 6 is a waveform diagram of a transient voltage and a control signal in a capacitor detected by a detection circuit at the moment when a key cell of the keyboard according to the present invention is pressed or removed.

Explanation of symbols

10, 50 Keyboard 12, 52 Key module 14, 58 Processor 54 Detection circuit 56 Parallel / serial register 60, 61 Key cell 64, 65 Capacitor 66 Amplifier 68 Positive comparator 70 Negative comparator 72 OR gate

Claims (6)

A keyboard, the keyboard
A key module comprising at least one key cell whose output can be selectively electrically connected to the first voltage or the second voltage;
A detection that is electrically connected to the output of the key cell and produces a control signal whenever the voltage at the output of the key cell is switched from the first voltage to the second voltage or from the second voltage to the first voltage. Circuit,
A parallel / serial register electrically connected to the output of the key cell;
A keyboard comprising a processor electrically connected to the parallel / serial register and controlling the operation of the parallel / serial register by a control signal.   2. The keyboard according to claim 1, wherein the detection circuit includes at least one capacitor corresponding to a key cell in the key module.   3. The keyboard according to claim 2, wherein the detection circuit further includes an amplification circuit for amplifying a voltage in the capacitor.   The detection circuit further includes a pair of comparators for comparing and detecting whether a voltage output from an output terminal of the amplifier circuit is within a predetermined range, and generating a control signal according to the comparison result. Item 3. The keyboard according to item 3.   The pair of comparators includes a positive comparator that generates a control signal when the voltage output from the output terminal of the amplifier circuit exceeds the positive reference voltage, and the voltage output from the output terminal of the amplifier circuit is a negative reference voltage. 5. The keyboard of claim 4, further comprising a negative comparator that produces a control signal when below.   5. The keyboard according to claim 4, wherein the detection circuit further includes an OR gate having an input terminal electrically connected to an output terminal of the pair of comparators and an output terminal outputting a control signal.

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