JPS6055846B2 - keyboard switch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a keyboard switch device, and more particularly to a keyboard switch device comprising a large number of non-contact switches arranged.

A non-contact key switch generates an output from a magneto-electric conversion semiconductor such as a Hall element in response to a key press operation.

Therefore, a signal processing circuit for processing the output from the magneto-electric conversion semiconductor is generally integrated into an IC together with the magneto-electric conversion semiconductor, and is housed within the case of the key switch. That is, the non-contact key switch has an IC circuit including a magneto-electric conversion semiconductor, and outputs a non-contact digital output in response to a key press operation. A keyboard switch device is formed by arranging a large number of the above-mentioned key switches, and in recent years, as operators have become more skilled, high-speed keystrokes have become more common.

For this reason, it is necessary to ensure that correct output is produced even when a plurality of keys are pressed one after the other. In other words, multiple key switches are turned on in sequence.
When N is selected, coded signals corresponding to each key are sequentially output in the order in which they are turned on, regardless of the order in which they are turned off.
Key rollover functionality is required. Furthermore, recent keyboard switch devices are required to have a so-called repeat function. This repeat function is a function in which by pressing a desired single key and pressing the repeat key, the coded signal and strobe signal corresponding to that key are sequentially and continuously output at a predetermined period. . In view of the above-mentioned requirements, it is an object of the present invention to provide a keyboard switch device using a non-contact key switch, which has both an N-key rollover function and a repeat function.

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

In FIG. 1, an IC circuit 2 is provided in each key switch, and includes a magnetoelectric conversion semiconductor 21 such as a Hall element.
and transistors 22 and 23 forming an output circuit. The collectors of the transistors 22 and 23 are connected to output terminals 24 and 25, respectively, and when an output is generated from the magnetoelectric conversion semiconductor 21, an "L" output is generated from the respective output terminals 24 and 25. This IC circuit 2
The output terminal 24 of the
A differentiating circuit consisting of is attached externally. This differential output is sent through externally connected diodes 14 and 15 as two differential outputs Ql and Q2. Further, a resistor 16 is externally connected to the output terminal 25, and a digital output Q3 is outputted via this resistor 16. That is, in the embodiment shown in FIG. 1, each key switch has a built-in IC circuit 2 that generates two digital outputs (square wave outputs), and it is possible to externally connect a resistor or capacitor to this 1C circuit. I have to. In this way, two differential outputs are obtained from one digital output,
The other digital output is output as is. Of course, the IC including the externally attached circuit parts in Figure 1
It may also be built into each key switch. The pulse outputs Ql and Q2 generated from the circuit 1 of each key switch shown in Fig. 1 are input to the encoder circuit 3 as shown in Fig. 2, and the coded signal corresponding to the pressed key is output to the output line. It is output from 31.

Furthermore, the digital output Q3 generated from the circuit 1 of each key switch is used for one detection. It is input to circuit 4. This detection circuit 4 is composed of two sets of voltage dividing resistors 41, 42; 43, 44, two comparators 45, 46, and a NAND circuit 47. The resistors 41 to 44 are set so that the voltage V1 obtained by the voltage dividing resistors 41 and 42 is smaller than the voltage V2 obtained by the voltage dividing resistors 43 and 44. When one key is pressed, the input voltage VO of the detection circuit 4 becomes a voltage proportional to the voltage division ratio of the resistors 17 and 16.

When two resistors are pressed, two resistors 16 are connected in parallel.
The voltage is determined by the voltage division ratio between the resistor 17 and the resistor 17. In this way, the input voltage VO becomes lower as more keys are pressed. When no key is pressed, input voltage VO becomes equal to power supply voltage Vcc.

This input voltage V. By detecting a change in , it is possible to detect that only one key is being pressed. Therefore, voltage V1 is set to a value lower than the voltage generated when one key is pressed, and higher than the voltage generated when two keys are pressed, and voltage V2 is set to a value lower than the voltage generated when one key is pressed. The voltage is set lower than the voltage when no keys are pressed, and higher than the voltage that would occur if only one key was pressed. Then,
If no keys are pressed (VO>V2>
V1), the output of the comparator 45 is "H", but the output of the comparator 46 is "L". When only one key is pressed (because V2>VO>V1), the outputs of comparators 45 and 46 both become "H". When two or more keys are pressed (because V2>V1>VO), the output of the comparator 45 becomes "H" and the output of the L upper comparator 46 becomes "H". Therefore,
NAND circuit 47 goes "L" only when one key is pressed
produces an output of The output of this detection circuit 4 is the NOR circuit 6
Sent to 1. The output from the repeat key switch 5 is sent to the NOR circuit 61''.The output from the repeat key switch 5 is further sent to the NAND circuit 62.
is being sent to. When the repeat key is pressed, the output from the repeat key switch 5 becomes "L" and an output is generated from the NOR circuit 61. The output of this NOR circuit 61 is sent to a NAND circuit 63, and this NOR circuit 61
The clock pulse is gated by the output of . A clock pulse gated by the output of the NOR circuit 61 is output from the N,AND circuit 63, and the clock pulse gated by the output of the NOR circuit 61 is output.
is sent to one input terminal of The STO output (strobe signal) of the encoder circuit 3 is also sent to the N,AND circuit 62. The output of this NAND circuit 62 is NO
The signal is sent to the other input terminal of the NOR circuit 64 via the T circuit 65. The output of the NOR circuit 64 is used as a strobe signal (trigger signal). In the circuits shown in Figures 1 and 2, the key is pressed at high speed,
When the next key is pressed so that it turns 0N before the previous key turns 0FF, the pulse output signals Ql and Q2 generated at the moment the key starts to be pressed are input to the encoder circuit 3, so they are immediately pressed. A coded signal is output.

That is, each key will be evaluated later than the time it was first pressed, and the coded output will occur immediately in that order.
N-key rollover functionality is implemented. Next, when one key is pressed and the repeat key 5 is pressed, an output is generated from the detection circuit 4, so that the clock pulse becomes NOR
It is input to one input terminal of the circuit 64. Since one key is pressed, encoder circuit 3 outputs STO (
strobe signal) is generated, so that while the repeat key is pressed, the other input terminal of the NOR circuit 64 has an AN
Signals are constantly being sent via the D circuit 62 and NOT circuit 65.

As a result, only one key is pressed and the repeat key 5
While the keys are pressed at the same time, the NOR circuit 64 will produce an output according to the clock pulse. Therefore, if this output is used as a strobe signal, it is possible to continuously output coded signals corresponding to the keys pressed at the cycle of the clock pulse. In this way, the repeat function is realized. Therefore, according to the present invention, it is possible to realize a keyboard switch device having both an N-key rollover function and a repeat function.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a part of the circuit of an embodiment of the present invention;
FIG. 2 is a block diagram showing the overall configuration. 1... Circuit of each key switch, 2...
IC circuit, 21...Magnetoelectric conversion semiconductor circuit, Ql
, Q2...Pulse output, R...Digital output, 3...Encoder circuit, 4...
・Detection circuit, 5...Repeat key switch.

Claims (1)

[Scope of Claims] 1. A plurality of key switches that include a magnetoelectric conversion semiconductor and generate two non-contact digital outputs in response to a pressing operation, and a differential that obtains a differential output from the digital output of one of the key switches. an encoder circuit into which the differential output is input and which produces a coded signal corresponding to the pressed key, and an encoder circuit into which the other digital output of each of said keyswitches is input, and only one key is pressed; a detection circuit that detects this, a repeat key switch that generates a digital output when the repeat key is pressed, and an output of the detection circuit and the repeat key switch that is inputted,
A keyboard switch device comprising a circuit that generates a strobe signal of a predetermined period only when both are input at the same time. 2. The keyboard switch device according to claim 1, wherein the detection circuit comprises two comparators that detect two different levels and an AND circuit that takes an AND condition of the outputs of the comparators.