JPH0433122A - Keyboard display controller - Google Patents

Abstract

PURPOSE:To increase the number of circuits controlled by means of a central processing unit by installing a programmable controller to use as the external device of the central processing unit and connecting a keyboard and a display. CONSTITUTION:The programmable controller 4 is installed as the external device of CPU 1 and the keyboard 2 and the display 3 are connected to the controller 4. The time division function of dynamic lighting and the scan function of a key matrix are previously given to the controller 4. Only data and a command are issued from CPU 1 to the controller 4 and the controller 4 reads input from a switch input circuit in the keyboard 2 by itself and outputs data to the LED driving circuit of the display 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a keyboard/display controller.

(Prior art and its secrets) In a conventional keyboard/display controller, the switch input circuit of the keyboard and the LED drive circuit of the display were each connected to a central processing unit, that is, a CPU board, and were directly controlled by this CPU. However, there is a limit to the number of switch input circuits and LED drive circuits that can be controlled by the CPU. Furthermore, when there are a large number of these circuits, dynamic lighting of LEDs and scan signals based on time division of switches are used, which poses a problem of heavy software burden and complexity.

(Means for Solving the Problems) The present invention was invented to solve the above problems, and its gist consists of a keyboard comprising a switch input circuit, a display comprising an LED drive circuit, and a keyboard comprising a switch input circuit; A keyboard/display controller comprising a central processing unit for controlling the keyboard/display controller, characterized in that a programmable controller is installed as an external device of the central processing unit, and the keyboard and display are connected to the programmable controller.

(Function) Since the present invention has the above configuration, when the central processing unit issues a necessary instruction to the programmable controller, the programmable controller itself reads input from the switch input circuit of the keyboard, and Output to the LHDI%li dynamic circuit of the display.

(Example) One embodiment of the invention is shown in FIG.

In FIG. 1, l is a central processing unit, i.e., CPU, 2
3 is a keyboard consisting of a switch input circuit, 3 is a display consisting of an LED drive, 4 is a programmable controller, and 5 is a decoder.

This programmable controller 4 is installed as an external device of the CPU 1, and a keyboard 2 and a display 3 are connected to this programmable controller 4.The programmable controller 4 has a dynamic lighting time division function, a key matrix function, etc. If a scanning function is provided, data and commands are simply given to the programmable controller 4 from the CPU 1, and the programmable controller 4 then reads input from the switch input circuit of the keyboard 2 by itself.
Moreover, it is output to the LED drive circuit of the display 3.

(Effect of the invention) In the present invention, the programmable controller is installed as an external device of the central processing unit, and the keyboard and display are connected to this programmable controller. Therefore, when the central processing unit issues the necessary instructions to the programmable controller, the programmable controller It reads the input from the keyboard's switch input circuit and outputs it to the display's LED drive circuit.

In this way, the number of switch input circuits and LED drive circuits that can be controlled by the central processing unit can be increased without increasing the load on the central processing unit. Furthermore, the central processing unit can perform other tasks after outputting the necessary instructions to the programmable controller.

Additionally, if the programmable controller is provided with a dynamic lighting time division function and a key matrix scanning function, the burden on the software will be reduced and this can be simplified using Luno.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

Claims (1)

[Claims] In a keyboard/display controller consisting of a keyboard comprising a switch input circuit, a display comprising an LED driving circuit, and a central processing unit that controls these, a programmable controller is installed as an external device of the central processing unit, and the programmable controller is equipped with the keyboard and the display unit. A keyboard/display controller characterized by a display connected.