JPH03172910A - Keyboard device - Google Patents

Abstract

PURPOSE:To prevent the malfunction of a system main body by not outputting the on-codes of the last key which causes a phantom state and the a phantom key erroneously detected by the phantom state but outputting the off-code. CONSTITUTION:A control means 11 selects a decoder 12 to output a scan signal to only one of Y lines and simultaneously reads in the states of X lines at this time to read information corresponding to one line and compares this information with preceding read information to detect the change of the key information. When the number of keys whose turning-on is detected in one line is two or more, the phantom state is decided. That is, key information is compared with present key information of the other Y lines, and the occurrence of the phantom state is decided when coinciding key information is found. The on-codes of the last key which causes the phantom state and the key erroneously detected by the phantom state are not outputted, but only the off-code is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a keyboard device used in computer terminals, etc., and in particular to a keyboard device that can prevent malfunctions caused by current leakage that occurs when a key switch is pressed multiple times. It is related to.

Conventional technology When a key is pressed multiple times on a keyboard device in which key switches are arranged in a matrix.

The problem is the current loop.

FIG. 5 is a diagram illustrating a wrap-around state in a conventional key switch section. In the fifth cause, when keys 1, 2, and 3 are pressed and key 4 is in the open state, when the Yl line is selected, current wraps around as shown by the broken line, and it appears as if key 4 was pressed. Detected. This is a so-called phantom state, and this key 4 is called a phantom key. Skilled operators perform key operations at high speed, so when three or more keys are pressed at the same time, so-called multiple presses often occur.If the multiple pressed keys are in the positional relationship indicated by L, a phantom state occurs. This phantom key is a key that is not actually pressed, and if the on code of this key is output to the main body of the system, problems such as malfunctions will occur.

For this reason, conventionally, a sixth
As shown in the figure, each key is equipped with a diode to prevent backflow, and a diode method is used to achieve N-key rollover. 2) A microcontroller counts the number of keys pressed and does not allow more than 3 keys to be pressed at the same time. Key lock out method,
■If a key is pressed multiple times as described in U.S. Patent No. 4,420,744, it is determined whether the state is a phantom state or not, and only the keys that are not involved in the phantom state are output (in the fifth cause, key 1, If key 2 is pressed and then key 3 is pressed.

Keyboard devices are known that employ a pseudo N-key rollover method that prevents malfunctions by not outputting the key codes of key 3 and key 4, which is a phantom key.

Problems that the invention aims to solve However, in the diode method of Okiki■.

A diode is required for each key, resulting in an increase in cost due to an increase in the number of parts and an increase in manufacturing man-hours. The two-key lockout method (2) requires no diode and is low cost, but it has the problem of not being able to follow high-speed key operations. In addition, when the pseudo N-key rollover method described in This is time-consuming and obstructs the operator's rhythmic keystrokes. Alternatively, there are problems such as input errors being difficult to detect.

The present invention solves these conventional problems,
It is an object of the present invention to provide an excellent keyboard device capable of realizing pseudo N-key rollover with high productivity, low cost, and good operability without using a diode for preventing IE current leakage.

Means for Solving the Problems In order to solve the problem in item t, the present invention provides a phantom state detection means that detects wraparound by comparing the currently detected key information with the previous key information, and when a phantom state is detected. , the last key that caused the phantom state and the on code of the phantom key that is erroneously detected due to the phantom state are not output, but the off code is output. Further, by providing an alarm means in the keyboard device or the system main body, the operator can be made aware of the phantom state.

action When a phantom state is detected due to the configuration described above.

Since the off code is output without outputting the on code of the last key that caused the phantom state or the phantom key that is erroneously detected due to the phantom state, it is possible to reliably prevent malfunction of the system main body, and still This eliminates the need for a diode for preventing current leakage, and therefore it is possible to realize a pseudo N-key rollover with high productivity, low cost, and good operability. Furthermore, by using a warning means such as emitting a warning sound on the keyboard device or the system main body side, it is possible to take countermeasures such as notifying the operator of the phantom status, making it easier to correct mistakes, etc. Since all keys can be processed as long as the state does not occur, pseudo N-key rollover can be realized.

Example An embodiment of the present invention will be described below based on the drawings.

FIG. 1 (a l (bl) is a block and key switch diagram showing the configuration of a keyboard device according to an embodiment of the present invention. In FIG. 1, 11 is a key matrix scanning means, a key code output means, a phantom state detection means,
12 is a decoder for scanning the key matrix; 13 is a key matrix composed of a plurality of row lines and column lines; and 14 is provided at the intersection of the row lines and column lines. A key switch 15 is an interface with the system main body.

According to the structure, the control means 11 has a storage section therein for storing on/off information of the key switch 14 corresponding to the key matrix 13, and the key matrix 13 is stored in the decoder 1.
2, and the obtained information on the key switch 14 is written into this storage section as needed. For example, when key switch 1°4 is turned on, the corresponding bit is set to 1.
and set it to 0 when off is detected. Then, the obtained information is converted into a key code and the keyboard interface 15
Output to the system main unit through.

Next, the operation of the embodiment will be explained in detail using the flowchart shown in FIG. The control means 11 first performs initial settings of the internal storage necessary for scanning (step 1).
. Next, select the decoder 12 and select the Y line (YO~Y
A scanning signal is output to only one line among the lines (N, N is an arbitrary integer) (step 2). X line at this time (XO~X
By reading the states of M and M are arbitrary integers at once, information on the key group for one line is obtained (step 3). The information on this read line is compared with the previous information on the same line (step 4), and a check is made to see if there is a key whose state has changed (step 5). If there is no change key, scan the next line.

If there is a change key, it is checked whether the key changed from off to on or from on to off (step 6). If the key has been turned off, the off code for that key is output (step 11). If the key has turned on, count the number of keys that are turned on in that line (step 7), and if there is only one key, output the on code for that key (step 8), and store the current state in the memory. Store (step 9). If there are two or more keys detected as being on in one line, a phantom state may be occurring, so a phantom state determination is performed. The procedure for this determination will be described below. When the X line is read and 2 or more keys are turned on, this information is temporarily saved in a register in the storage unit, and this saved data is compared with the current key information of the remaining Y lines (step 1
2). If the data match at this time, it is determined that a phantom state has occurred. Compare all remaining Y lines, and if there is no matching line, it is determined that a phantom state has not occurred, and using the same processing method as when only one key is on as described in section L, each key is Code processing is performed (step 13). If the key is judged to be in a phantom state and was off last time, but has changed from off to on this time, it outputs an off hood instead of the on code for the key to notify the system that it is a phantom key (step 14). Further, if it is determined that the state is a phantom state, the matrix in the storage unit is not updated, and only information on keys that are confirmed to be turned on is written in the matrix in the storage unit. When the phantom status has been determined, check whether all lines have been scanned in step 10.
), if it is not completed yet, return to step 2 and scan the first line. Once all lines have been scanned.

Return to step 1 to perform initial settings and start scanning from the beginning.

As described above, according to embodiment t, when a phantom state occurs due to wraparound, the on code of the last key that caused the phantom state and the phantom key that is erroneously detected due to the phantom state is not output, and the off code is output. This prevents system malfunctions and notifies the system of the presence of the phantom key. Also.

Since all keys can be processed as long as they do not enter the phantom state, it has the effect of realizing a pseudo N-key rollover.

In addition, in the embodiment described in section h, when a phantom state occurs due to wraparound, the on code of the last key that caused the phantom state and the phantom key that is erroneously detected due to the phantom state is not output, but an off code is output. However, if this key is a key such as a shift key or a control key that changes the mode without leaving the system, sending the off code will change the mode and subsequent input will be disabled. There may be a problem that the process is not performed properly. So if the key in the phantom state is a special key like this, instead of the off code for that key.

It is also possible to output an off code for any key that is unrelated to other mode changes. This can prevent malfunctions such as mode changes in the system main body. Further, a dedicated phantom code may be determined in advance and output instead of the off code.

In addition, in the embodiment described above, an on code is output for keys that are pressed in a state other than the phantom state, but in consideration of operability, the phantom state continues after the phantom state is entered and an off code is output. If the phantom state is canceled, a method may be used in which key input is not accepted and the code is not output until the phantom state is released. In this case for the operator.

This has the effect that key input omissions can be immediately recognized and keys can be re-entered each time, making correction work easier. Further, although the key matrix 13 is scanned through the decoder 12, the control means 11 may scan it directly. In this case, it has the effect of reducing the number of parts.

FIG. 3 (altb) shows a block diagram and a key switch diagram of a keyboard device according to a second embodiment of the present invention.

The present invention is characterized in that a phantom state alarm means is provided inside the keyboard device. In FIG. 3, numeral 16 indicates an alarm means for notifying the occurrence of a phantom state, and is controlled by the control means 11. The alarm means 16 is equipped with a buzzer or the like, and by emitting a warning sound or the like when a phantom state occurs, the operator can be made to recognize the phantom state audibly. It is also possible to provide visual recognition by providing an LED or the like instead of a buzzer.

FIG. 4 shows a third embodiment of the present invention, in which when an off code due to the occurrence of a phantom state is input from the keyboard device, the system body uses a built-in alarm means to notify the operator of the phantom state. It is characterized by the fact that it is designed to be In FIG. 4, a system main body 22 connected to a keyboard device 21 includes a main body interface 23 connected to the keyboard device 8, an I10 control means 24 that processes data from the keyboard group @21, and an internal control unit that controls the entire system. It is provided with means 25 and means 26 for alarming the occurrence of a phantom state. Therefore, by providing the system main body 22 with the phantom state occurrence warning means 26, it is possible to prevent the system main body from malfunctioning due to the phantom key, and also to make the operator aware of the presence or absence of the phantom state. If a buzzer or the like is provided as the warning means, the operator can be audibly recognized by emitting a warning sound or the like when a phantom state occurs. Install an LED, etc. instead of a buzzer. Alternatively, the occurrence of the phantom state can be visually recognized by indicating the occurrence of the phantom state on the display.

Effects of the Invention According to the present invention, the on code of the last key that caused the phantom state and the phantom key that is erroneously detected due to the phantom state is not output, but the off code is output. It is possible to prevent malfunction of the phantom key, and to notify the system body of the existence of the phantom key. Furthermore, by using a warning means such as emitting a warning sound at this time, the keyboard device or the system main body side can take countermeasures such as informing the operator of the phantom state.

This has the effect that mistakes can be easily corrected.

In addition, all keys can be processed as long as they do not enter the phantom state, so a pseudo N-key rollover can be achieved.
Furthermore, since conventional methods do not require diodes for the number of keys required to implement N-key rollover, it is possible to provide an inexpensive keyboard device with high productivity.

[Brief explanation of the drawing]

FIG. 1 (aHbl is a schematic block diagram and keypad border diagram of a keyboard device according to an embodiment of the present invention, FIG. 2 is a flowchart showing key code processing of a control means in the same keyboard device, and FIG. ) is a schematic block diagram and a key switch diagram of a keyboard device showing another embodiment of the present invention which is provided with an alarm means for the occurrence of a phantom state, and FIG. A block diagram showing still another embodiment of the invention, FIG. 5 is a diagram illustrating a wrap-around state in a key switch section of a conventional keyboard device, and FIG. 6 is a switch of a conventional keyboard device provided with a diode for preventing wrap-around. It is a block diagram of parts. 11... Control means, 12... Decoder, 13...
Key matrix, 14...Key switch, 15...
Keyboard interface, 16...Alarm means, 2
1...Keyboard device. 22... System main body, 23... Main body interface. 24... I10 control means, 25... Internal control means,
26...Warning means.

Claims (1)

[Scope of Claims] 1. A key switch group composed of a plurality of row lines and column lines arranged in a matrix, and means for detecting the pressed state of each key by scanning the key switch group; When a new state change key is detected by the above scan, means for outputting an on code from the pressed key when pressed and an off code from the key when released from being pressed, and comparing the currently detected key information and the previous key information. and a phantom state detection means for detecting wraparound, and when a wraparound is detected, an off code is output without outputting the on code of the last key that caused the wraparound and the phantom key that is erroneously detected due to the wraparound. Keyboard device configured in . 2. The keyboard device according to claim 1, wherein the off-code to be output when the wraparound is detected is not the off-code of the last key or the phantom key but the off-code of any key. 3. The keyboard device according to claim 1 or 2, further comprising means for making an operator recognize the occurrence of the wraparound audiovisually when the wraparound is detected. 4. The keyboard according to claim 1 or 2, wherein the keyboard is connected to a system main body having means for making an operator recognize the occurrence of the wraparound audio-visually in response to off-code output due to wraparound detection, so as to make the operator recognize the occurrence of the phantom state. Device.