JPH11259217A - Keyboard identifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a keyboard identifying device for correctly detecting the operating state of a key even when two keys are pressed, and for detecting specification setting. SOLUTION: This device is provided with a specification setting part 4 in which one part of the matrix cross points of a keyboard 1 arranged like a matrix is connected through a resistance Rs. At the time of retrieving the key operating state by a keyboard scan part 2, the potential of a connected key data output V2 of the specification setting part 4 is compared with the output voltage of a reference voltage generator 6 by a voltage comparator 5 so that the presence or absence of the resistance Rs of the specification setting part 4 can be detected. Thus, the set specification of the keyboard can be identified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-key roll-over type keyboard having a specification setting section.

[0002]

2. Description of the Related Art Some keyboards have specifications in which the number of key matrices and key tops are different in order to correspond to various languages, and it is necessary to change a keyboard controller program according to the keyboard specifications.

Conventionally, in a keyboard, a matrix intersection not used for key input as in Japanese Patent Application Laid-Open No. Hei 6-326798 is short-circuited or opened for specification setting and specification identification, and device specifications are determined. I was going.

FIG. 2 is a configuration diagram showing specification settings of a conventional keyboard. In FIG. 2, after the outputs of the tristate buffers P1 to Pn in the keyboard scanning unit 2 are all set to high impedance under the control of a microcontroller (not shown), the L level is sequentially set to P1 to Pn one by one. 11, the key data outputs D1 to Dn from the keyboard 11 at that time are input to the microcontroller via the buffers I1 to In of the output unit 3, and the microcontroller reads the key input position and the specification setting state. .

FIG. 2 shows the specification setting section 14 in a specification setting state in which the intersection of the tri-state buffer P2 and the key data D3 is short-circuited.

In this conventional example, for example, a keyboard 11
If the key switches K12 and K13 are pressed,
When the output of the tri-state buffer P2 is set to L level in order to read the state of the specification setting unit 14, both the outputs of the input buffers I2 and I3 of the output unit 3 become L, and it is as if the key switch of K23 is pressed. Is incorrectly determined as follows.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a keyboard identification device which does not cause the above-described erroneous determination and can be used at low cost for setting and identifying specifications.

[0008]

In order to solve the above-mentioned problems, a keyboard identifying apparatus according to the present invention comprises a two-key roll-over keyboard comprising a plurality of movable contacts arranged in a matrix, and the keyboard. A specification setting unit that connects a part of the matrix intersection with a resistor, and a keyboard scanning unit that searches for the operation state of the movable contact,
A comparator that compares the voltage of the key data involved in the specification setting unit with the reference data with the key data output from the keyboard, and when the keyboard scanning unit is searching for the input key position, It is configured to detect the setting state of the specification setting unit according to the output.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a two-key roll-over type keyboard comprising a plurality of movable contacts arranged in a matrix, and a part of a matrix intersection of the keyboard. And a comparator for comparing the output potential of the keyboard with a reference potential, wherein the keyboard scan unit is in a key input state. In the keyboard identification device, the setting state of the specification setting unit is detected by the output of the comparator when the search is performed.Inexpensive, easy, without the possibility of erroneous key operation detection. The effect that the setting state of the specification setting unit can be identified can be obtained.

According to a second aspect of the present invention, in the keyboard identification device according to the first aspect, the resistor for the specification setting section is a printed resistance. Since it can be produced at times, an effect that it can be manufactured at low cost is obtained.

Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. (Embodiment 1) FIG. 1 is a configuration diagram of Embodiment 1 of a keyboard identification device of the present invention.

In FIG. 1, the tristate buffer P2 of the keyboard scan unit and the key data output V of the keyboard are shown.
A resistor Rs is connected to the matrix intersection between the two lines to form a specification setting unit 4, and the key data output V2 is connected to a voltage comparator
To identify the setting state of the specification setting unit 4.

This discriminating operation is performed by the tri-state buffers P1 to P1 of the keyboard scanning unit 2 in the form of the specification setting unit 4.
After all the outputs of Pn are set to high impedance, the L level is output to the tristate buffer P2, and the key data output V2 at that time is compared with the reference voltage generator 6 by the comparator 5.
The comparison is made with the output voltage of

If the specification setting section 4 has a setting resistor Rs, the pull-up resistor to the power supply voltage Vc of the key data output V2 line is Rp2, and the voltage input to the comparator 5 is Rs / (Rs + Rp). × Vc, and becomes Vc when there is no specification setting resistor Rs. Therefore, the output voltage of the reference voltage generator 6 is calculated as the voltage Rs / (Rs + Rp) × V
If it is set between c and Vc, the presence or absence of the set resistor Rs can be detected.

Further, by making the resistance value of Rs sufficiently higher than Rp, even if the key switches K12 and K13 in the keyboard 1 are pressed at the same time, the output unit 3 can output the key data V3 at L level. Since it is not detected that there is, the key input operation state of the keyboard can be correctly detected.

Since the specification setting resistor Rs can be simultaneously manufactured as a printing resistor when the printed wiring of the keyboard 1 is formed, the manufacturing cost can be reduced.

In the first embodiment, two types of specification setting examples are shown depending on whether or not one specification setting resistor is connected to one of the matrix intersections. It is easy for those skilled in the art that two or more types of specifications can be set depending on whether or not the resistor is connected.

[0018]

As is apparent from the above, according to the present invention, a two-key roll-over type keyboard including a plurality of movable contacts arranged in a matrix and a part of the matrix intersection of the keyboard are provided. The keyboard scanning unit includes a specification setting unit connected by a resistor, a keyboard scanning unit that searches for an operation state of the movable contact, and a comparator that compares an output potential of a keyboard matrix with a reference potential. When the search of the position is performed, the setting state of the specification setting unit is detected by the output of the comparator, so that the specification setting state can be detected without erroneous detection of the key operation.

Further, since the specification setting resistor Rs can be simultaneously manufactured as a printing resistor when the printed wiring of the keyboard 1 is created, an inexpensive specification setting section can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of Embodiment 1 of a keyboard identification device of the present invention.

FIG. 2 is a configuration diagram showing specification settings of a conventional keyboard.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Keyboard 2 Keyboard scan part 3 Output part 4 Specification setting part 5 Voltage comparator 6 Reference voltage generator

Claims (2)

[Claims] 1. A two-key roll-over type keyboard comprising a plurality of movable contacts arranged in a matrix, a specification setting unit for connecting a part of a matrix intersection of the keyboard with a resistor, and the movable contact. A keyboard scan unit for searching for the operation state of the keyboard, and a comparator for comparing the output potential of the keyboard with a reference potential.When the keyboard scan unit is searching for a key input state, the output of the comparator indicates A keyboard identification device for detecting a setting state of the specification setting unit. 2. The keyboard identification device according to claim 1, wherein the resistor in the specification setting section is a printing resistor.