JPH03251891A - Display controller - Google Patents

Abstract

PURPOSE:To prevent gradations from deviating from a set color code when a gradational display is made on a monochromatic display device by providing a color conversion table, a multi-bit memory which can be set from outside, and a gradation level selecting means. CONSTITUTION:A display control part 2A includes a timing generator 20 - a gradation processing part 24 which are similar to conventional constitution and a memory 25 for gradation selection which is added to the color conversion table 22, and the processing part 24 is connected to the memory 25. When color codes of the conversion table 22 are as shown in a figure (a), the content of the memory 25 which can be arbitrarily designated from outside is set as shown in a figure (b). Therefore, when 1st - 4th and 5th - 8th colors can be classified by four gradations, the gradations are set as shown in a figure (c) according to their use frequencies and the four expected colors can be discriminated. When there is data which can not be discriminated on the screen of a monochromatic liquid crystal display device 5, the gradations can free be adjusted. Namely, the memory for two-gradation selection is provided in accordance with the color codes and set optionally from outside.

Description

[Detailed description of the invention] [Industrial application field] This invention is a monochrome (hereinafter referred to as monochrome).

) The present invention relates to a display control device for displaying a displayed image, which is the output of a computer system, in gradations on a monochrome display device such as a liquid crystal display (LCD).

[Prior Art] The configuration of a conventional example will be explained with reference to FIGS. 3 and 4.

FIG. 3 is a block diagram showing a conventional display control device, and FIG. 4 is a circuit diagram showing a gradation processing section of the conventional display control device.

In FIG. 3, the conventional display control device includes a frame memory (]) which is a memory for display data, a display control section (2) connected to this frame memory (1), and a display control section (2) connected to this frame memory (1). a memory access control unit (3) whose input side is connected to the frame memory (1) and whose output side is connected to the frame memory (1);
It is composed of. Incidentally, a color CRT (4) which is a color display device and a monochrome liquid crystal display (LCD) (5) are connected to the display control section (2).

The display control unit (2) also includes a timing generator (20).
and a parallel/serial converter (21) connected to this timing generator (20) and frame memory (1).
, a color conversion table (22) connected to this parallel/serial converter (21), and a timing generator (20).
), a timing generator (20), a color conversion table (22) and a gradation processing unit (24) connected to the synchronization signal generator 23). ing.

The memory access control unit (3) includes a timing generator (20
), and the color CRT (4) is connected to the color conversion table (
22) and a synchronizing signal generating section (23), and the monochrome liquid crystal display (5) is connected to a gradation processing section (24) and a synchronizing signal generating section (23).

In FIG. 4, the gradation processing section (24) includes a ternary counter (240) connected to the synchronizing signal generating section (23), and an N counter connected to the ternary counter (240).

T gate (241), color conversion table (22), 3
It consists of a forward counter (240) and a selector (242) connected to a NOT gate (241).

Next, the operation of the above-mentioned conventional example will be explained with reference to FIG.

FIG. 5 is a timing chart showing the operation of a conventional display control device.

The frame memory (1) stores the display data for each of red (R), green (G), and blue (B>) representing the displayed image. Each color data is successively outputted in 8-bit order. Let MR, MG, MB be memory access control unit (3
) is given to the frame memory (1), display data MR, MG, MB are sent to the display control unit (2).
) is read out.

Display data MR output from frame memory (1),
MG and MB are respectively given to parallel and serial converters (21), where serial data SR-SG
, is converted to SB.

The color conversion table (22) is composed of eight 6-bit registers, each register storing 6-bit color data. One display data VD is selected from these eight registers by three bits of serial data SR-SG and SB and is applied to the color CRT (4 lines).

The color CRT (4) receives the synchronization signal SCI from the synchronization signal generation section (23) in the display control section (2), and displays the displayed image in color in synchronization with this.

Note that the timing generator (20) in the display control unit (2)
is a memory access control section (3), a parallel/serial converter (21), an l@key processing section (24), and a synchronization signal generation section based on externally applied clock signals C1, -K. (23) A basic timing signal TM is generated and supplied, and the entire display control device operates according to this basic timing signal TM.

In order to give display data for a color image to the monochrome liquid crystal display (5) and display it, a color conversion table (22
The display data VD converted by ) is further supplied to a gradation processing section (24) and converted into gradation data PD that can change the gray level. This gradation data PD
The tone processing section (24) is generated in synchronization with the synchronization signal SC2 given from the synchronization signal generation section (23) to the tone processing section (24).
4) is applied to the monochrome liquid crystal display (5).The monochrome liquid crystal display (5) displays the image to be displayed in accordance with the synchronization signal SC3 provided from the synchronization signal generator (23).

Here, the operation in the gradation processing section (24) will be explained.

The ternary counter (240) receives the vertical clock signal V CL K from the synchronizing signal generator (23) at its input terminal T, and generates an output signal from its output terminal QA.

The vertical clock signals VCL, K are one of the synchronizing signals SC2 generated by the synchronizing chair signal generator (23), and are signals having the same period as the vertical synchronizing signal applied to the monochrome liquid crystal display (5).

The output signal from the ternary counter (240) is input to the input terminal D1 of the selector (242) for selecting a gradation. Further, the output signal is inverted by the NOT gate (241), and the inverted signal is applied to the input terminal D2 of the selector (242). Furthermore, the selector (242)
The input terminal DO is grounded, and the input terminal D3 is connected to the power supply. The signals input to these input terminals DO to D3 are gradation level signals that include four gradations, and one of them is selected and output as gradation data PD. .

Fifth (2I is a timing chart diagram showing signals input to four input terminals DO to D3, hereinafter, signal DO
~ Referred to as D3.

The signal DI is at a high level "°H" once every three cycles of the vertical clock signal VCLK, and the signal D2 is at a high level "H".
is a signal obtained by inverting the signal D1.

Further, the signal DO is always at a low level "L", and the signal D3 is always at a high level "H".

If, for example, the signal Do is selected as the R1 tone data PD, the tone data PD will always be at a low level and the display will be turned off.
(For example, it will appear white on a black and white display). Furthermore, if the signal D3 is selected, the gradation data PD is always at a high level, and the display is turned on (the display is displayed in black on a monochrome display).

On the other hand, the signal D1 turns on the display once every three frames (a frame refers to the display cycle of one screen on the display), and the signal D2 turns on the display twice every three frames. Become. Usually the frame period is about 15m
Because it is very short at 5ec, for example, if you display ○N only once every three cycles like signal D1, to the human eye it will be 1/3 as dark as when all frame display is ON (signal D3). appear.

Therefore, four gradations of light and shade can be expressed by the signals DO to D3.

Two bits out of six hits of the output VD from the color conversion table (22) are input to select input terminals A and B of the selector (242). These 2 bits allow the signal DO
~D3 is selected and displayed on the monochrome liquid crystal display (5) as gradation data PD.

[Problems to be Solved by the Invention] In the conventional display control device as described above, eight types of commonly used color codes (6 bits) are preset in the color conversion table (22), and can be freely changed. cannot be changed. FIG. 2(a) shows an example of data stored in the color conversion table (22). In FIG. 2(a), for example, D3 and D2 are selenium l of the selector (242).
- If you input to input terminals A and B, all 4 gradations will be selected, or if you input D5 and D4, 2 gradations, Dl,
D.

If , only one gradation is selected, that is, only two colors or one color (in this case, the screen disappears) can be displayed for the display data in the frame memory (1). Therefore, if the select/input 2 bits of the selector (< 242) are fixed in hardware, the 6-bit color code will change depending on the software, making it impossible to distinguish between colors (gradations). There was a problem with it disappearing.

The present invention was made to solve the above-mentioned problems, and the present invention provides display control that ensures that the gradation does not vary with respect to a set color code when displaying gradation on a monochrome display device such as a monochrome liquid crystal display. The purpose is to obtain equipment.

[Means for Solving the Problems] A display control device according to the present invention includes the following means.

(i>, color conversion table storing multiple color codes for color display;

(ii) A multi-bit memory in which data corresponding to the color code stored in the J2 color conversion table can be externally set.

<iii> A gradation level selection means for selecting one of a plurality of gradation levels using the output of the memory as a selection input and outputting the selected gradation level to the monochrome display device.

[Operation] In this invention, data corresponding to the color code stored in the color conversion table is arbitrarily set in the memory of a plurality of tone selection pixels from the outside, and it is possible to determine what kind of color code change. The gradation can also be effectively selected.

[Embodiment] The configuration of an embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a block diagram showing one embodiment of the present invention, in which a frame memory (1), a memory access control section (3
) ~ The monochrome liquid crystal display (5) is completely the same as that of the above-mentioned conventional device.

In FIG. 1, an embodiment of the present invention includes: - exactly the same as that of the conventional device described above, and a display control section (2^);
It is composed of.

The display control unit (2^) includes a timing generator (20) to a gradation processing unit (24) of the display control unit (2) of the conventional device described above.
), and a gradation selection memory (25) added to a color conversion table (22). Note that the gradation processing section (24) has a gradation selection memory (25).
)It is connected to the.

By the way, the gradation level selection means of the present invention is comprised of the gradation processing section (24) in the above-described embodiment of the invention.

Next, the operation of the above embodiment will be explained with reference to FIG.

FIGS. 2(a) to 2(c) are reference diagrams showing the contents of the color conversion table (22) and tone selection memory (25) of one embodiment of the present invention.

Color conversion table (22) set in some software
Assume that the color code of is shown in FIG. 2(a). On the other hand, the contents of the gradation selection memory (25), which can be specified arbitrarily from the outside, are set as shown in FIG. 2(b). In this way, from the first color to the fourth color, Alternatively, it is possible to distinguish colors from the fifth color to the eighth color or by using four gradations. Depending on the content of the display data, for example, the first, second, seventh, and eighth colors may be mainly used, and the remaining colors may be used less frequently. In that case, by making settings as shown in FIG. 2(c), the expected four colors can be distinguished.

As described above, in one embodiment of the present invention, data for tone selection can be arbitrarily set externally in accordance with the frequency of use of colors used by the software, so that the data on the screen of the monochrome liquid crystal display toy (5) If there is data that cannot be distinguished, you can freely adjust it.
In other words, in order to change the gradation for displaying a color image on a monochrome display device in accordance with the specified color, a memory for selecting two gradations is provided corresponding to the color coat, and an external This has the effect that it can be set arbitrarily.

1. Effects of the Invention] As explained below, the present invention provides a color conversion table storing a plurality of color codes for color display, and data corresponding to the color codes stored in this color conversion table. The present invention is equipped with a multi-bit memory that can be set from a plurality of bits, and a gradation level selection means that uses the output of the memory as an input for selection and selects one of a plurality of gradation levels and outputs it to the monochrome display device. When performing gradation display on a display device, there is an effect that the gradation does not vary with respect to the set color code.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a reference diagram showing the contents of a color conversion table and gradation selection memory in an embodiment of the invention, and Fig. 3 is a conventional display control diagram. FIG. 4 is a block diagram showing the device, FIG. 4 is a circuit diagram showing a gradation processing section of a conventional display control device, and FIG. 5 is a timing chart showing the operation of the conventional display control device. In the figure, (1) frame memory, (2A) display control section, (3) memory access control section, (4) color CRT (5) monochrome liquid crystal display, (20)
... Timing generator, (21) ... Parallel/:/real converter, (22) ... Color conversion table (23) - Synchronization signal generation section, (24) - Gradation processing section, (25) - - Memory for tone selection. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a display control device that displays a displayed image in gradation on a monochrome display device, a color conversion table in which multiple color codes for color display are stored, and data corresponding to the color codes stored in this color conversion table are externally transferred. and a gradation level selection means for selecting one of a plurality of gradation levels using the output of the memory as an input for selection and outputting the selected gradation level to the monochrome display device. display control device.