JPH117272A - Display controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display controller simultaneously displaying the number of colors of the number of bits or above per one dot of the display data stored in a ROM with less ROM capacity. SOLUTION: A color data transformation part 6 divides the color transformation data to two sets by making 16 colors one set of color palette to store them, and further, a display code stored on a RAM 3 is constituted of a palette selection bit for selecting either one set between two sets of color palettes. Then, a ROM address generation part 4 decodes the display code from the RAM 3, and outputs a palette selection signal for selecting either one set between the color palettes in the color data transformation part 6 based on the palette selection bit to the color data transformation part 6 to select the displaying color palette to be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a display control device for displaying data on a display device such as a CRT.

[0002]

2. Description of the Related Art In recent years, in order to display various information such as channels and volume on a display device such as a CRT, display data stored in a ROM is read out in the order of display codes stored in a RAM, and RGB display data is read out. A display control device for converting into a TV set is used in a TV set or the like.

FIG. 2 is a block diagram of a conventional display control device, 101 is a display control device, 102 is a CPU, 103
Is a RAM, 104 is a ROM address generator, 105 is R
OM, 106 is a color data conversion unit for storing RGB display data for 32 colors, and 107 is a display device. The display device 107 shows a display example when a character string “ABCD” is displayed.

[0004] The operation of the conventional display control device configured as described above will be described below. In the RAM 103,
The display code is read based on the display code address input from the CPU 102, and the display code is output to the ROM address generation unit 104. The RAM 103 has a CPU
The display code has been stored in advance by 102.

In the ROM address generation unit 104, a RAM
The display code input from the terminal 103 is decoded, and a display data address corresponding to the display code is generated.
Output to

In the ROM 105, display data is read based on the display data address from the ROM address generation unit 104, and the display data is transferred to the color data conversion unit 106 by one.
Output for each dot.

The color data converter 106 converts the display data into RGB display data so that it can be displayed on the display device 107, and outputs the RGB display data to the display device 107. As a result, the display data is displayed on the display device 107 in the order of the display codes stored in the RAM 103.

The display code stored in the RAM 103 has a bit indicating the end of display. When the decoder of the ROM address generation unit 104 detects the bit indicating the end of display, the CPU 102 is notified of the end of display and the display is completed. I do.

Further, the display control device 101 has a color data conversion unit 106 composed of 32 colors.
To simultaneously display 32 colors on 7, the display data stored in the ROM 105 is composed of 5 bits per dot.

[0010]

However, in the above-described conventional display control device, even if 16 colors are sufficient to be displayed in units of characters, one display is stored in the ROM 105.
Since display data has to be stored as data of 5 bits per dot, there is a disadvantage that ROM resources are wasted.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem in the conventional configuration and to provide a display control device capable of simultaneously displaying multiple colors with a small ROM capacity.

[0012]

According to the present invention, there is provided a RAM for outputting a display code based on a display code address input from a CPU, and a ROM for generating and outputting a display data address based on the display code. In a display control device comprising: an address generation unit; a ROM that outputs display data according to the display data address; and a color data conversion unit that converts the display data into RGB display data, the color data conversion unit converts the color conversion data. A plurality of color palettes for storing separately; a display code stored in the RAM having a palette selection bit for selecting a display color palette from the plurality of color palettes; A generating unit that decodes the display code having a palette selection bit, It is characterized in that selecting a color palette for display from among the plurality of color palette by outputting Tsu bets selection signal to said color data converting unit.

With this configuration, 16 colors can be displayed in units of characters and 32 colors can be simultaneously displayed on the entire display device screen, and the ROM only needs to store display data composed of 4 bits per dot. Therefore, the capacity of the ROM for storing the display data can be saved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a display control device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a display control device according to the present embodiment. In FIG. 1, 1 is a display control device, 2 is a CPU, 3 is a RAM, 4 is a ROM address generation unit, 5 is a ROM, and 6 is a color palette of 16 colors, which is divided into two sets of color conversion data and stored. The color data conversion unit 7 configured to perform the operation is a display device. In addition,
The display device 7 shows a display example when a character string “ABCD” is displayed.

An example of the operation of the display control device of the present embodiment configured as described above will be described below.
In the RAM 3, the display code is read by the display code address input from the CPU 2, and the display code is read from the ROM 3.
Output to the address generation unit 4. This RAM 3 has a CP
The display codes are stored in advance in the display order by U2, and the display codes are stored in the color data converter 6.
Has a palette selection bit for selecting one of the two color palettes.

The ROM address generator 4 decodes the display code input from the RAM 3, generates a display data address corresponding to the display code, and outputs the display data address to the ROM 5.

In the ROM 5, display data is read out by the display data address from the ROM address generation unit 4,
The display data is output to the color data converter 6.

The decoder of the ROM address generator 4 outputs a palette selection signal to the color data converter 6 based on a palette selection bit provided in the display code input from the RAM 3. According to the palette selection signal, one of the two color palettes in the color data converter 6 is selected as a display color palette.

The color data converter 6 converts the display data into RGB display data based on the display data and the pallet selection signal so that the display device 7 can display the data, and outputs the RGB display data to the display device 7. Thereby, RAM3
The display data is displayed on the display device 7 in the order of the display codes stored in the display device.

The display code stored in the RAM 3 is provided with a bit indicating the end of display. When the decoder of the ROM address generation unit 4 detects the bit indicating the end of display, the CPU 2 is notified of the end of display and the display is completed. I do.

As described above, according to the embodiment of the present invention, the color data conversion unit 6 stores the color conversion data separately into two sets as 16 sets of color palettes as one set of color pallets, and also stores the color conversion data in the RAM 3. The display code includes a pallet selection bit for selecting one of the two sets of color pallets of the color data conversion unit 6. The ROM address generation unit 4 decodes the display code, A palette selection signal for selecting one of the two sets of color palettes of the color data conversion unit 6;
, The display color palette is selected, and 32 colors can be simultaneously displayed on the entire display screen.

In the above embodiment, 16 colors are simultaneously displayed in units of characters, and 3 colors are displayed in the entire display screen.
Although the embodiment in which two colors are desired to be displayed at the same time has been described, the color data conversion unit is provided with a plurality of color palettes, and a display color palette can be selected from the plurality of color palettes by a palette selection signal. Thus, the number of display colors can be increased more than 32 colors.
Further, in the present embodiment, R is used for storing display data.
Although OM is used, it goes without saying that RAM may be used.

[0024]

As described above, according to the present invention, the color conversion data is stored in a plurality of color pallets, and the display color pallet to be used is selected from the plurality of color pallets by the pallet selection signal. It is possible to realize an excellent display control device capable of performing multi-color display even if the capacity of the ROM storing the data is small.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a display control device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional display control device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 display control device 2 CPU 3 RAM 4 ROM address generation unit 5 ROM 6 color data conversion unit 7 display device

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Makoto Hirano 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Hisao Kamiya 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Shin Kawamura 1006 Odaka Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co.

Claims (1)

[Claims] 1. A RAM for outputting a display code based on a display code address input from a CPU, a ROM address generating unit for generating and outputting a display data address based on the display code, and outputting display data based on the display data address. A display control device comprising: a ROM; and a color data conversion unit that converts the display data into RGB display data, wherein the color data conversion unit includes a plurality of color palettes for separately storing the color conversion data, The display code stored in the RAM has a palette selection bit for selecting a display color palette from the plurality of color palettes, and the ROM address generator decodes the display code having the palette selection bit. And outputting a palette selection signal to the color data conversion unit. Thus the display control device and selects the display color palette from said plurality of color palettes.