JPH01179991A - Crt display device - Google Patents

Abstract

PURPOSE:To expand a display image in accordance with the use of a user by providing a character generator ROM in which information fixed in accordance with the use is stored, a RAM in which data is written, a circuit which selects them, and a means which displays an optimum pattern based on the signal from said circuit. CONSTITUTION:A character generator (CG) ROM 3 in which information fixed in accordance with the use of the user is stored, a CG RAM 4 in which data is written, and a data processor 1 which outputs data to be written in the CG RAM 4 are provided. Further, a selecting circuit 5 which selects the ROM 3 and the RAM 4, a CRT code generating circuit 7 which outputs the address and data required for display, a display circuit 6 which displays an optimum pattern in accordance with the use based on the signal from the selected ROM 3 or RAM 4, and a display CRT 2 are provided. Thus, data according with the use of the user is written in the CG RAM to display an image easiest to see (in case of positive/negative) or display different CG.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a CRT display device, and particularly to a display pattern selection method using a character generator (CG).

[Conventional technology]

Conventional CRT display devices normally display the contents of the CG ROM as they are, for example, if they have a CG ROM for positive display, and when displaying negative, they simply invert the bits of one dot. , or by lowering the brightness.

[Problem to be solved by the invention]

In the method described by Jing, since the contents of one type of CG ROM are read and displayed, there is a drawback that in the case of inverted display, thin lines are crushed or parts become dark.

In addition, in order to make the CG ROM more convenient, only the CG written in the ROM can be displayed. For example, if the CG is composed of 16 x 16 dots, only the characters composed of 16 x 16 dots will be displayed, making it difficult for the user to use it. It had the disadvantage that it could not be expanded at all depending on the purpose.

An object of the present invention is to provide a CRT display device that eliminates the above-mentioned problems.

[Means to solve the problem]

The present invention comprises a character generator ROM that stores fixed information according to the purpose of use of the user, and a character generator R that writes data according to the purpose of use of the user.
AM, and a selection circuit that selects the ROM and RAM;
The present invention is a CRT display device characterized by having display means for displaying the most optimal pattern according to the purpose of use based on a signal from a selected ROM or RAM.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

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

The present invention includes a character generator (CCG) ROM3 that stores fixed information according to the user's purpose of use;
A character generator (CG) RAM 4 into which data is written according to the purpose of use by the user, and the CG RAM 4
a data processing device 1 that outputs data to be written in the ROM 3, a selection circuit 5 that selects the ROM 3 and the RAM 4, a CRTC code generation circuit 7 that outputs addresses and data necessary for display, and a selected ROM 3 or It has a display circuit 6 that displays the most appropriate pattern depending on the purpose of use based on the signal from the RAM 4, and a display CRT 2.

In the embodiment, the data processing device 1 writes data according to the user's purpose into the CG RAM 4 using the address bus 104 and the data bus 103. For example, CGROM
If 3 is a positive CG, the content written to the CG RAM 4 may be negative, or the content written in the CG RAM 4 may have the same positive character structure (this refers to a CG character different from the CG RAM 4).

Kanji for ANK, 24 for 16x16 dots
24-dot characters, etc.). On the other hand, the data processing device layer 1 operates the selection circuit 5 using the control signal 11, and the selection circuit 5 selects the CGROM 3 or CG RAM.
4 is selected by using control signal 12 or 13. Furthermore, the data processing device 1 operates the CRTC code generation circuit 7 using the control signal 14. CRTC code generation circuit 7 is connected to address bus 10
2. CG RO selected using data bus 101
Read data from either M3 or CG RAM4, and read data from the selected CGROM3 or CG RAM4.
Either one sends the data at the address shown in the CRTC code generation circuit 7 to the display circuit 6, and the display circuit 6
It will be displayed on RT 2. 15 is a control signal output from the CRTC code generation circuit 7 to the CRT 2.

〔Effect of the invention〕

As explained above, the present invention uses two types of CG ROM, CG
It has a RAM, and by writing data according to the purpose of use by the CG RA old user, it is possible to
) CG In addition to displaying only a single data, which is a disadvantage of the CRT display method, by selecting between CG ROM and CG RAM, you can display the most visible 'l-1 screen (in case of positive/negative), Or a completely different CG
It has the effect of being able to display.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. 1...Data processing device 2...CRT3...CG
ROM 4...CG RAM5...
・Selection circuit 6...Display circuit 7...CRTC
code generation circuit

Claims (1)

[Claims] 1. A character generator ROM that stores fixed information according to the user's purpose of use, and a character generator RAM that writes data according to the user's purpose of use.
A CRT display device comprising: a selection circuit for selecting the ROM or RAM; and display means for displaying the most optimal pattern according to the purpose of use based on a signal from the selected ROM or RAM. .