JPH04268910A - Keyboard control device - Google Patents

Abstract

PURPOSE:To provide a keyboard control device capable of attaining reliable signal transfer between a keyboard and a device body. CONSTITUTION:In the case of executing signal exchange between the keyboard 6 and a host device 1 through a serial signal line 3a, a status signal instructing a signal transfer direction is sent from the host device 1 to the keyboard side. The status signal is transmitted from a status output circuit 4 through a status signal line 4a. The transmission/reception control of the keyboard 6 or the host device 1 is executed in accordance with the status signal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a keyboard control device for controlling signal transfer between a keyboard used in, for example, a document creation device and the main body of the device.

0002

[Background Art] Conventionally, in document processing devices or personal computers, etc., serial transfer is used to transfer signals between a keyboard and the main body of the device (host device) in order to reduce the number of signal lines and simplify interface connections. method is adopted.

[0003] CPU (Central Processing Unit) on the device main body side
transmits command data, an ACK signal (reception response signal), etc. to the keyboard side through the serial signal line. On the other hand, the keyboard transmits key input data, ACK signals, etc. to the device main body side through the same serial signal line.

[0004] Between the main body of the device and the keyboard,
It is controlled by a fixed sequence, and serial transfer is performed in which an ACK signal is transmitted when data is mutually received.

[0005]

SUMMARY OF THE INVENTION Signals such as data or ACK signals are exchanged between the keyboard and the main body of the device by serial transfer under certain sequence control. Such serial transfer has the problem that failures such as key data dropping from the keyboard or multiple occurrences are likely to occur due to the influence of noise and the occurrence of interrupts.

An object of the present invention is to provide a keyboard control device that can realize reliable signal transfer in serial transfer between the keyboard and the main body of the device.

[0007]

[Means for Solving the Problems] The present invention provides a keyboard control device that transfers serial signals between a keyboard main body and a host device. The apparatus includes an output means and a signal transfer control means for controlling signal transfer by a serial signal transfer means in accordance with a status signal.

[0008]

[Operation] In the present invention, when signals are exchanged between the keyboard body and the host device using the serial signal transfer means,
A status signal indicating the direction of signal transfer is sent from the host device to the keyboard body. Transmission and reception control of the keyboard body or the host device is executed in accordance with this status signal.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the basic configuration of the present invention. FIG. 3 is a block diagram showing the main parts of the document creation device according to the same embodiment.

As shown in FIG. 1, this system uses a host device (such as a document creation device or a personal computer).
The device has a main body (1) and a keyboard 6 which is an input device. The host device 1 includes a CPU 2 that controls the entire system and executes various data processing, a keyboard interface (K-IF) 3, and a status output circuit 4.

The keyboard 6 is controlled by the keyboard controller 5 and inputs various key input data to the host device 1. The keyboard controller 5 is connected to the keyboard interface 3 by a serial signal line 3a. Further, the keyboard controller 5 is connected to the status output circuit 4 by a status signal line 4a. Key input data input from the keyboard 6 is transferred to the host device 1 through the serial signal line 3a, and command data etc. from the host device 1 are transferred to the keyboard controller 5.

The status output circuit 4 outputs a status signal for instructing the transfer direction of data transferred through the serial signal line 3a under the control of the CPU 2.
It is transmitted to the keyboard controller 5 via the status signal line 4a.

[0014] The keyboard controller 5 and the keyboard interface 3 each include a buffer memory for temporarily storing data. The keyboard controller 5, depending on the logic level of the status signal,
Controls transmission and reception of data transferred through the serial signal line 3a.

The host device 1 of the present invention is, for example, the main body of a document creation device, as shown in FIG. C of this device
The PU2 controls the entire device, executes document creation processing, editing processing, and the like. The display control unit (display-CNT) 9 controls the display 11 to display the document data developed in the display RAM 10 and various input screens.

Printer interface (PRT-I)
F) 12 is a printer such as a kanji serial printer (PR
T) Output print data to 13 and print document data, etc. The FDD-IF 14 is an interface for a floppy disk device (FDD) 15, which is an external storage device, and performs data read/write control for the FDD 15.

Furthermore, this device has a ROM 7 and a RAM 8. The ROM 7 stores various programs corresponding to the basic operations of the CPU 2, character patterns for display or printing, and dictionaries. RAM8 is CPU2
Stores programs, document data, and various control data corresponding to specific operations.

Next, the operation of this embodiment will be explained.

As shown in FIG. 2, the status output circuit 4
Under the control of the CPU 2, when the key input data KD is transmitted from the keyboard 6, it outputs a status signal of logic level "H". Also, from the host device 1
When the K signal or command data CMD is transmitted, a status signal of logic level "L" is output.

Basically, the status output circuit 4 outputs a status signal of logic level "H". That is, in the normal state, key input data KD can always be transmitted from the keyboard 6 to the host device 1.

The CPU 2 of the host device 1 detects the level of the status signal of the status output circuit 4, and sets the level of the status signal to logic level "H" in the normal state (steps S1 and S2 in FIG. 4).

When the status signal is at the logic level "H", the keyboard controller 5 transmits the key input data KD input from the keyboard 6 and stored in the buffer memory through the serial signal line 3a (step S3). . The keyboard interface 3 starts receiving the key input data to be transmitted, and when the reception is completed (end of transmission), the keyboard interface 3 starts receiving the key input data to be transmitted.
A K signal will be transmitted (YES in step S4)
.

Here, when the data transmission from the controller 5 is completed, the CPU 2 outputs the status output circuit 4.
The status signal from the controller is set to logic level "L" (steps S5 and S6). This status signal causes
Data transmission from the host device 1 to the keyboard controller 5 side becomes possible. That is, the keyboard interface 3 connects the serial signal line 3a under the control of the CPU 2.
The ACK signal is transmitted through (step S7).

When the transmission of the ACK signal is completed (YES in step S8), the CPU 2 changes the logic level "L" of the status signal to the logic level "H" (step S9). This will return to the normal state and the keyboard 6
From then on, key input data KD can always be transmitted to the host device 1.

Next, the CPU 2 reads the command data CMD.
When transmitting to the keyboard controller 5, the status signal is set to logic level "L" (steps S10 and S11 in FIG. 5). Furthermore, after a certain period of time has elapsed (YES in step S12), the CPU 2 transmits command data CMD through the keyboard interface 3 and the serial signal line 3a (step S12).
13). In this case, if data transmission from the keyboard 6 to the host device 1 is in progress, the controller waits until the transmission is completed, and then transmits the command data CMD.

When the transmission of the command data CMD is completed, the CPU 2 changes the logic level "L" of the status signal to the logic level "H" (steps S14 to S16).
). The keyboard controller 5 is a command data CM
When the reception of D is completed, A is transmitted through the serial signal line 3a.
A CK signal is transmitted (step S17). When the transmission of the ACK signal is completed (YES in step S18), the C
The PU2 changes the logic level "H" of the status signal to the logic level "L" (step S19).

[0027] When transmitting the command data CMD continuously, the CPU 2 uses the keyboard interface 3
and command data CM through the serial signal line 3a.
Continue sending D. When the transmission of the command data CMD is completed, the CPU 2 changes the logic level "L" of the status signal to the logic level "H". Further, if there is no command data CMD to be transmitted continuously, the logic level "L" of the status signal is changed to the logic level "H" after a certain period of time (steps S29, S21
). As a result, the normal state is restored, and the key input data KD can always be transmitted from the keyboard 6 to the host device 1.

In this way, if the direction of data transfer is specified from the keyboard 6 side to the host device 1 side according to the level of the status signal controlled by the host device 1 side, the keyboard is transferred via the serial signal line 3a. Key input data from 6 is transmitted. On the other hand, host device 1
The side sets the level of the status signal, specifies the direction of data transfer from the host device 1 side to the keyboard 6 side, and transmits command data CMD and the like.

In other words, data transmission and reception between the host device 1 side and the keyboard 6 side is controlled according to the level of the status signal transmitted through the status signal line 4a. In the normal state, the host device 1 side receives key input data from the keyboard 6 side, but on the other hand, when transmitting command data CMD or the like, it changes the level of the status signal. Depending on the level of the status signal, the keyboard 6 side stops transmitting key input data when data is transferred from the host device 1 side.

Therefore, since the method is not serial transfer under constant sequence control as in the past, but is controlled by a status signal controlled by the host device 1 side, Failures such as key data falling off from the keyboard or multiple occurrences can be reliably prevented.

[0031]

[Effects of the Invention] As detailed above, according to the present invention, reliable signal transfer is achieved by adopting a control method according to the level of the status signal in serial transfer between the keyboard and the main body of the device. be able to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of an embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the embodiment.

FIG. 3 is a block diagram showing main parts of a document creation device according to the same embodiment.

FIG. 4 is a flowchart for explaining the operation of the embodiment.

FIG. 5 is a flowchart for explaining the operation of the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Host device, 2...CPU, 3...Keyboard interface, 3a...Serial signal line, 4...Status output circuit, 4a...Status signal line, 5...Keyboard controller, 6...Keyboard.

Claims (1)

[Claims] 1. A keyboard body for inputting various input data to a host device, a key input signal from the keyboard body being transmitted to the host device, and various signals from the host device being transmitted to the keyboard body. a serial signal transfer means for transmitting a status signal indicating a signal transfer direction from the host device to the keyboard body when signals are exchanged between the keyboard body and the host device by the serial signal transfer means; 1. A keyboard control device comprising: a status output means; and a signal transfer control means for controlling signal transfer by the serial signal transfer means in accordance with a status signal from the status output means.