JPH0566745A - Screen display - Google Patents

Abstract

(57) [Summary] [Purpose] A part of the display program can be rewritten to support various screen controllers. [Structure] A display program consisting of a program for executing a first module and a program for executing a second module independent of the first module is stored in a program ROM 5, and display data converted by the first module is stored in a virtual logical screen The display data fetched in the RAM 8 and fetched in the virtual logical screen RAM 8 is further converted by the second module and transferred to the CRT controller 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen display device for displaying characters and the like on a screen.

[0002]

2. Description of the Related Art A conventional screen display device is shown in FIG. In FIG. 3, the display data output from the external device 1 is supplied to the data receiving unit 3 via the serial input / output unit 2. The data receiving unit 3 temporarily stores the display data and outputs the display data according to a certain rule.

When the display mode is selected, the CPU 4 reads the display program data from the program ROM 5 and converts the display data from the data receiving section 3. The display data is displayed by the CRT controller 6 by this display program.
Are converted into display data that can be processed. The converted display data is transferred to the CRT controller 6 and displayed on the CRT 7.

[0004]

However, since the display program needs to be programmed based on the hardware of the CRT controller 6, if the CRT controller 6 is changed to a different type, the display program must be rewritten. did not become. The total rewriting of the display program has drawbacks such as an increase in design man-hours.

Therefore, it is an object of the present invention to provide a screen display device which can cope with various screen controllers without rewriting all of the display program.

[0006]

A screen display device according to the present invention for achieving the above object comprises means for converting display data by a first module, and a virtual logical screen RAM for storing the converted display data. And this virtual logical screen RA
It comprises a means for converting the display data stored in M by a second module that operates independently of the program for executing the first module, and a screen controller for inputting the converted display data.

[0007]

Therefore, when the screen controller is changed, the program for executing the second module may be changed so as to be converted into the display data suitable for the hardware of the screen controller.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show one embodiment of the present invention.

FIG. 1 shows a circuit block diagram of the screen display device. In FIG. 1, the display data output from the external device 1 is the serial input / output unit 2 as in the conventional example.
It is guided through the data receiving unit 3. When the display mode is selected, the CPU 4 reads the program data for executing the first module of the display program from the program ROM 5, and the display data from the data receiving unit 3 is converted by the first module.

The program ROM 5 is, for example, an interrupt routine which is independent of the program for executing the first module as a display program and this program routine,
And a program for executing the second module. The former program does a simple format conversion on the display data,
The latter program uses the format-converted display data for CR
Conversion to a mode suitable for the hardware of the T controller 6.

The display data converted by the first module is written in the virtual logical screen RAM 8. The display data once written in the virtual logical screen RAM 8 is read by a timer interrupt or a vertical period interrupt by a program that executes the second module, and the read display data is converted based on the second module. The converted display data is transferred to the CRT controller 6.

The CRT controller 6 which is a screen controller drives the CRT 7 based on the transferred display data. When a liquid crystal display is used instead of the CRT 7, the screen controller is a liquid crystal controller.

On the other hand, the remote control receiver 9 and the operation key unit 10
Each output of is supplied to the key command analysis unit 11, and the command signal analyzed by the key command analysis unit 11 is the CPU 4
Is taken into. The CPU 4 executes various modes based on this command signal, and controls various circuits to execute the flowchart shown in FIG. 2 when the display mode is selected, for example.

The operation of the above configuration will be described below. For example, when the display mode is selected by the operation key unit 10, the display data from the external device 1 is converted by the first module,
The converted display data is once written in the virtual logical screen RAM 8. The written display data is further converted by the second module, transferred to the CRT controller 6, and displayed on the CRT 7.

Here, when the display data handled by the CRT controller 6 is converted into a different display data, the program for executing the first module is not rewritten and only the program for executing the second module is converted. It may be rewritten so as to be converted into a display data format that can be processed by the CRT controller 6.

Further, if two virtual logical screen RAMs 8 are prepared and each virtual logical screen RAM 8 is configured to capture character data and attribute data separately, fine screen display can be performed.

Furthermore, by adapting the conversion data in the first module to a general-purpose display screen format, a general-purpose CRT can be obtained.
It will be possible to transfer data to and simulate
Useful when debugging. Further, if the display data of the virtual logical screen RAM 8 is configured to be block-transferred, the apparent processing speed is improved.

Furthermore, by providing the CRT controller 6 with a cursor control function and the like, the virtual logical screen RA
The transfer process from the M8 to the CRT controller 6 can be simplified.

[0019]

As described above, according to the present invention, the display program is divided into a program for executing the first module and a program for executing the second module independent of the first module. When the controller is changed, only the program that executes the second module needs to be rewritten, which has the effect of reducing the number of design steps.

Further, since the display program is divided into two, the program is simple and the number of bugs is reduced.
Further, there is an effect that maintenance becomes easy.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a screen display device (embodiment).

FIG. 2 is a flowchart of a display program (embodiment).

FIG. 3 is a circuit block diagram of a screen display device (conventional example).

[Explanation of symbols]

6 ... CRT controller (screen controller), 8 ... Virtual logical screen RAM.

Claims (1)

[Claims] 1. A unit for converting display data by a first module, a virtual logical screen RAM for storing the converted display data, and display data stored in the virtual logical screen RAM for the first module. A screen display device comprising means for converting by a second module that operates independently of a program to be executed, and a screen controller for inputting the converted display data.