JPS63199395A - Color display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color display device, and particularly to a color display device suitable for use in a system that simultaneously displays a system display area and a user display area on a display screen. Regarding.

[Conventional technology]

Conventional color display devices are, for example, r N W X, -
As shown in the instruction manual for ``2251235 Graphic Image System,'' image data recorded as digital signals is read out from the image memory, and the color signals in the image data are used to determine the level of each R2O and B color using a color table. D
/A converter converts the signal into an analog signal and sends it to the display 205.

FIG. 2 shows the configuration of such a color display device. For example, when a straight line is to be displayed, a microprocessor 200 sends the addresses of the start and end points of the straight line to an address generator 201. The address generator 201 is a commonly used DDA (Digital Differential Analyzer), and generates an address for a series of points for displaying a straight line connecting a designated starting point and ending point, and sends it to the image memory 202. The image memory 202 consists of four memory planes and stores 4 bits of color information in the orthogonal direction, so it represents 16 colors represented by 2 to the 4th power, that is, color codes from O to 1.5. These graphic data are sequentially read out in one raster direction (horizontal direction) and sent out as pixel data, and the color code becomes an address signal of the color table 203, and the entry of that address is R, G.
, B signals, which are D/A converted and sent to the display 205. In the entries of the color table 203, R, G, and B signals can be set as necessary from the microprocessor 20'O.

[Problem that the invention seeks to solve]

Generally, in a terminal device having a color display device, display screens are used differently as shown in FIG. That is, there is a system display area 100 used in the system to display terminal status, menus, etc., and the user draws various figures using the display device.

It is divided into a user display area 101 for display.

Considering color display on such a screen, first, the number of colors that can be displayed simultaneously on the display 205 is limited to the number of colors that can be displayed simultaneously on the display 205.
It is determined by the depth bit number of 2, that is, the number of bits that can be used for one pixel, and in the case of 4 bits as shown in FIG. 2, 16 colors can be displayed simultaneously. However, these 16 display colors are the number of colors that can be displayed over the entire display screen area. Therefore, when there are two display areas as described above, if the number of colors used in the system display area is 8, the number of displayable colors that can be freely handled in the kneezer display area, that is, the color table 203, can be adjusted according to your preference. The remaining 8 settings can be
It's a color. Even in the user display area, if you use it while being aware of the colors used by the system in the system display area,
It is possible to express colors, but if the user wants to use a completely different color
Colors cannot be used. In order to make this possible with the conventional device, it is necessary to increase the number of planes of the image memory 202 by one, which poses a problem of increased cost.

An object of the present invention is to provide a safe color display device that allows a user to use all the colors determined by the depth bit number of the image memory, regardless of the number of colors handled by the system.

[Means for solving problems]

The purpose of the above is to provide two sets of color tables, one for the system display area and one for the user display area, which stores color information corresponding to the color code, and also to check whether the data read at a certain point is from the system display area. This is achieved by providing an area determination circuit for determining whether it is a display area, and determining which of the two color tables to use based on the determination result of this circuit.

[Effect]

The graphic data including the color code stored in the image memory is sequentially read out in one raster direction (X-axis direction) of the display in synchronization with the pixel readout frequency. The area determination circuit compares an address (x, y) synchronized with the pixel read frequency of the image memory and a user display area address (x, y) given from the microprocessor in synchronization with the pixel read frequency. This allows you to recognize the boundary between the system display area and the user display area, so
By switching between the two color tables at the timing when the boundary is detected, the colors displayed in the two display areas can be controlled. Therefore, in the user display area, the number of colors corresponding to the depth bit number of the image memory can be arbitrarily set and used.

Moreover, the area determination circuit and color table are extremely simple and safe circuits compared to the memory plane, and the device of the present invention can be realized at a low cost.

〔Example〕

Hereinafter, the present invention will be explained by examples. FIG. 1 shows an embodiment of a color display device according to the present invention.
The same microprocessor 200, address generator 201, image memory 202, DA converter 204, and display 205 are used as in FIG. 2, but two color tables 203 and 207 and an area determination circuit 206 are provided. This is different from before. Here, the color table 203 is a memory that determines the color of the user display area 101 in FIG. 3, and the color table 207 is a memory that determines the color of the system display area 100. Further, the area determination circuit 206 determines the display area on the display screen and generates timing for switching the color tables 203 to 207.

The operation of this embodiment will be explained next. First, as in the case of FIG.
8. Send the start and end point addresses of the figure (here, a line segment) to the address generator 201 via the address signal line 209. Address generator 201 generates a point sequence address signal 210 that approximates a line segment, which is input to image memory 202 .

It is assumed that the image memory 202 is composed of four memory planes as in FIG. 2, and stores a 4-bit color code in the depth direction. This 4-bit information is associated with 16 colors as color code data. Image memory 202
The color-coded graphic data stored in is sequentially read out as pixel data in one raster direction (horizontal axis direction) of the display, and is read out as pixel data in the color table 20 via the signal llA211.
3° 207 as their addresses. Each of the color tables 203 and 207 is a small memory with a capacity of 3 x 16 x 4 bits, and has colors red (R) and green (G) corresponding to 16 color codes.

A color signal representing the size of each component of blue (B) with 4 bits is stored. This is written in advance by the microprocessor 200 via the signal line 212, and is, for example, the address (5) of the color table 203.
) to white, change the address (R, G, B
) components are respectively (F, F, F) (F is 1
15 in hexadecimal). Table 2 set like this
The color signal of 03°207 is output corresponding to the color code read out from the image memory 202, and is output to the traffic light 2.
13, is converted into a video signal (analog signal) 213 by a DA converter 204, and is output to a display 205.

FIG. 4 shows the detailed configuration of the area determination circuit 206. First, the starting address in the X direction of the system display area is sent from the microprocessor 200 via signal lines 215 and 216 to
It is stored in the axis address register 221. The address counter 223 inputs the output of this register 221 to the DIN terminal via the signal line 222 and counts the read clock signal 217 of the image memory 202. The contents of the X address register 221 are set when the signal 227 is input. When the raster reaches the boundary between the user display area and the system display area in FIG. 3, that is, when the count value reaches the previously set value of the P224
is set. This flip-flop is also reset when signal 228 is generated at each raster end (-horizontal end). Therefore, at the beginning of each raster, the Q output of the flip-flop 224 is turned on, and the color table 203 is selected at the output of the gate 225.
The data in this color table 203 is read out as color information, which gives the color of the user area. When the raster moves to the right and enters the system display area, the flip-flop 224 is set by the output of the counter 223, so the color table 207 is selected via the gate 226, the color information of this color table 207 is read out, and the system Gives the color of the display area.

〔Effect of the invention〕

As is clear from the above embodiments, according to the present invention, both the user and the system can use all of the display colors determined by the number of bits of the image memory completely independently, and this can be achieved safely. be.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a conventional color display device, FIG. 3 is an explanatory diagram of a display screen, and FIG. 4 is the area determination circuit of FIG. 1. FIG. 2 is a diagram showing a detailed configuration example. 100... System display area, 101... User display area, 202... Image memory, 203, 207.
...Color table, 205...Display, 20
6... Area determination circuit, 221... X address register, 223... X address counter, 224... Flip-flop.

Claims (1)

[Claims] 1. An image memory that stores a color code and a luminance signal that specify the color of a display figure as digital signals for each pixel; A register that stores first and second color tables stored at each level, a boundary position between the first display area and the second display area on the display, and a luminance signal and color that are being read from the image memory. A counter detects the position of the code on the display by counting the reading signal, and the position detected by the counter is compared with the boundary position, and the detected position is displayed in the first display area. In some cases, the color code read from the image memory is converted into color information by referring to the first color table, and when the detected position is in the second display area, the color code read from the image memory is converted into color information. A color display device comprising a selection means for controlling conversion into color information by referring to the second color table. 2. The color display device according to claim 1, wherein the boundary position can be arbitrarily set in the register from the outside.