JPH10268855A - Split screen display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the maximum number of colors to be develapable simultaneously, without reducing the plotting speed even if a general purpose memory, in which only one bus is provided, is used. SOLUTION: When display data color address information for plural planes is read out from a picture memory by a read-out means 7, the quantity of information to be read out is made to be irreducible minimum by referring to a split screen control signal from a split screen control means 6 in addition to a plane read-out control signal from a central control device 1 and a read-out timing control signal from a timing control means 5, and reduction of a plotting speed is suppressed. Also, when superimposing display data color address information from a superimposing means 9 is converted to corresponding display data color information by a color palette 10, the maximum number of colors to be developable simultaneously is secured more without restricting the number of superimposing planes by referring to split screen control signal from a split screen control means 6 in addition to a color information control signal from the central control means 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a screen division display device which can divide a plurality of images by superimposing them on a screen display of a navigation system or a portable information terminal.

[0002]

2. Description of the Related Art FIG. 4 is a functional block diagram showing an example of such a conventional screen division display device. In FIG. 4, 1
7 is an image memory for storing display data color address information for a plurality of planes, 18 is a drawing means for writing display data color address information for a plurality of planes to an image memory 17, and 21 is a display for a plurality of planes from the image memory 17. Reading means for reading data color address information, 2
2 is an image memory 17 of the drawing means 18 and the reading means 21
Arbitration means for arbitrating the right to use the bus at the time of accessing the device; and 23, superimposing means for outputting display data color address information as a result of superimposing display data color address information for a plurality of planes from the reading means 21. , 2
Reference numeral 4 denotes a color pallet for converting the superimposed display data color address information from the superimposing means 23 into corresponding display data color information. Reference numeral 19 denotes display means for displaying the display data color information from the color pallet 24 as a display screen.
Reference numeral 16 denotes a central controller for outputting control signals to the drawing means 18, reading means 21, superimposing means 23, and color pallet 24. Reference numeral 20 denotes reading means 2.
1 and a timing control unit for outputting a control signal to each of the display units 19.

FIG. 5 is a schematic diagram showing the contents of screen division display by superimposing two planes corresponding to the contents of the image memory, and FIG. 6 is a schematic diagram showing the contents of screen division in one plane corresponding to the contents of the image memory. FIG.

Next, the operation will be described. First, the drawing means 18 writes display data color address information for a plurality of planes into the drawing memory 17 in accordance with a drawing control signal from the central control device 16.

In this case, in FIG. 5, two planes of a first plane 25 and a second plane 26 are stored in the drawing memory 1.
7, and in FIG. 6, one plane of only the plane 28 is drawn in the drawing memory 17. Here, in the area on the right side of the screen in the drawing of the first plane 25 in FIG. 5, display data address information that becomes transparent when superimposed on the second plane 26 is written.

Further, display data color information 15 for each color address 14 is previously written in the color pallet 24 according to a color information control signal from the central controller 16 as shown in FIG. The color palette in FIG.
Each of the first plane 25 and the second plane 26 in FIG. 5 represents a color palette that stores 16 color addresses, in other words, 16 display data color information. Number of bits required for color address is 1 for plane designation
There are a total of 5 bits, 4 bits for specifying the color in the same plane. Therefore, the display data color address information in FIGS. 5 and 6 is written with 4 bits per pixel.

In this state, the reading means 21 synchronizes the display data color address information for the required plane from the image memory 17 with the read timing control signal from the timing control means 20 to synchronize the display data color address information from the timing control means 20 with the display means 19 The data is sequentially read out in synchronization with the control signal and sent to the superimposing means 23. It should be noted that the reading means 21 receives a plane read control signal from the central control unit 16 and outputs the image memory 17 for each plane.
In advance, the designation of the read area and the number of planes to be read are specified in advance. In FIG. 5, the designation of the number of planes to be read is two, and in FIG. 6, the designation of the number of planes to be read is one.

[0008] The superimposing means 23 outputs a plurality of planes from the reading means 21 in accordance with a vertical order of superimposition between the plurality of planes and a color address as a transparent color, which is specified in advance by an overlay control signal from the central controller 16. The display data color address information is superimposed, and the resulting display data color address information is stored in the color palette 2
4

In FIG. 5, the first plane 25 is
By performing the superimposition so as to be above the plane 26, the second plane 2 is placed in the transparent color area of the first plane 25.
The display data color address information of the area corresponding to No. 6 is output, and the display data color address information of the first plane 25 is output as it is to the other areas. 27 is the first
The plane 25 shows the display data color address information superimposed on the second plane 26. In FIG. 6, the display data color address information of the plane 28 is output as it is as indicated by reference numeral 29.

In the color palette 24,
The display data color address information as the superimposition result is
The color information is converted into one of a group of color information designated in advance by a color information control signal from the central control unit 16 and is sequentially displayed as display data color information while synchronizing with a synchronization control signal from the timing control unit 20 to the display unit 19. It is sent to the display means 19.

Therefore, as shown in FIG. 5, a transparent color area is provided on the first plane 25 and is superimposed on the second plane 26.
Alternatively, the divided screen can be realized on the display unit 19 by drawing the divided screen on the plane 28 in advance as shown in FIG.

[0012]

However, in the conventional screen split display device as described above, when the screen split display is realized on the display means 19, the first plane 2 shown in FIG.
5 and the second plane 26 are superimposed by the superimposing means 23.
It is necessary to read out the display data color address information from 7 on two planes. Therefore, when an inexpensive general-purpose memory having only one bus is used as the screen memory 17, the bus of the image memory 17 is occupied for a long time in reading the display data color address information. However, there is a problem that the time during which the bus cannot be used to perform the drawing process, that is, the drawable time is shortened, and the drawing speed is reduced.

Conventionally, in order to solve this problem, an image memory having two or more buses is used as the image memory 17, but there is a problem that the cost is increased.

In the case shown in FIG. 6, a divided screen is drawn on one plane in advance, and is converted into display data color information in the color pallet 24 without being superimposed. The maximum number of colors is up to 16 colors, which are the planes of the superposition, in this case, one plane, and 2 colors including the transparent colors in FIG.
There is a problem that the number of colors is reduced in principle compared to 32 colors for the plane.

In order to solve this problem, a method of increasing the number of bits of display data color address information per pixel and increasing the color address of one plane in the color pallet 24 has been adopted. However, this method has a problem that the amount of display data color address information in drawing and reading increases, the required image memory capacity increases, the drawing speed decreases, and the memory cost increases.

Further, in both FIGS. 5 and 6, when, for example, map information is arranged as divided screens and each is to be scroll-displayed on the display means 19,
Each time the user scrolls, it is necessary to redraw the map information by the drawing means 18. If the drawing takes a long time,
There was a problem that the scroll speed was slow.

The present invention solves the above-described problem. Even if a general-purpose memory having only one bus is used as an image memory, the maximum number of colors that can be simultaneously formed without lowering the drawing speed is reduced. It is an object of the present invention to provide a screen division display device that can secure more screens.

[0018]

In order to solve the above-mentioned problems, a screen division display device according to the present invention is arranged such that, when readout means reads out display data color address information for a plurality of planes from an image memory by a readout unit, a readout from a central control unit is performed. In addition to the plane read control signal and the read timing control signal from the timing control means, the read operation is also performed by referring to the screen division control signal from the screen division control means. This makes it possible to minimize the amount of information to be read and suppress a decrease in drawing speed.

When the superimposed display data color address information from the superimposing means is converted into the corresponding display data color information by using a color palette, in addition to the color information control signal from the central control means, the screen division control means The above-described screen division control signal is also referred to.
As a result, the maximum number of colors that can be simultaneously colored can be ensured without being limited to the number of superimposed planes.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 of the present invention provides a central control unit, an image memory for storing display data color address information for a plurality of planes, and a display control signal from the central control unit. Drawing means for drawing on the image memory, display means, timing control means for outputting a synchronization control signal to the display means, division position control signal from the central control device and display from the timing control means. Screen division control means for outputting a screen division control signal in accordance with a position signal, a plane read control signal from the central control device, a read timing control signal from the timing control means, and a screen division control from the screen division control means Reading means for reading display data color address information for a plurality of planes from the image memory in response to a signal; A bus arbitration unit that arbitrates the image memory bus of the drawing unit and the reading unit; and a superposition control signal from the central control unit and a display data color address information for a plurality of planes from the reading unit. Superimposing means for outputting display data color address information; and superimposed display data color address from the superimposing means in response to a color information control signal from the central control means and a screen division control signal from the screen division control means. A color pallet for converting information into corresponding display data color information and outputting the converted data to the display means. When reading out display data color address information for a plurality of planes from the image memory by the reading means, a screen division control means is provided. Also, by referring to the screen division control signal from Information to a minimum, and the bus in the image memory can eliminate the decrease in the drawing speed by using a general-purpose memory only one.

When converting the superimposed display data color address information from the superimposing means into the corresponding display data color information using the color palette, the screen division control signal from the screen division control means is also referred to. The maximum number of colors that can be simultaneously colored on the display means can be ensured without being limited to the number of superimposed planes.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 1 is a functional block diagram showing a configuration of a screen division display device according to an embodiment of the present invention;
FIG. 2 is a schematic diagram showing the contents of the display screen corresponding to the contents of the image memory, and FIG. 3 is a schematic diagram showing the contents of the color palette.

In FIG. 1, 1 is a central control device such as a CPU, 2 is an image memory for storing display data color address information for a plurality of planes, and 3 is an image memory 2 according to a drawing control signal from the central control device 1. A writing means for writing display data color address information for a plurality of planes, a display means, a timing control means for outputting a synchronization control signal to the display means, and a division position control from the central control unit. A screen division control unit that outputs a screen division control signal in accordance with a signal and a display position signal from the timing control unit 5. Reference numeral 7 denotes display data for a plurality of planes from the image memory 2 in accordance with a plane read control signal from the central controller 1, a read timing control signal from the timing control means 5, and a screen division control signal from the screen division control means 6. Reading means for reading color address information,
Reference numeral 8 denotes a bus arbitration unit that arbitrates the right to use the image memory bus of the drawing unit 3 and the reading unit 7. 9 denotes an overlay control signal from the central control unit 1 and display data color address information of a plurality of planes from the reading unit 7. The superimposing means 10 for outputting the superimposed display data color address information in accordance with the color information control signal from the central control means 1 and the superimposing means 9 in response to the screen division control signal from the screen division control means 6 Is a color pallet which converts the superimposed display data color address information into the corresponding display data color information and outputs it to the display means 4.

In FIG. 2, reference numeral 11 denotes display data color address information of the first plane drawn in the image memory 2;
Reference numeral 2 denotes display data color address information of the second plane drawn in the image memory 2, and reference numeral 13 denotes display data color information obtained by dividing the screen displayed on the display means 4, that is, a divided screen. In FIG. 3, reference numeral 14 denotes a color address of the color pallet 10, and 15 denotes display data color information of the color pallet 10.

Next, the operation of the screen division display device configured as described above will be described.

First, the drawing means 3 writes display data color address information for a plurality of planes into the drawing memory 2 in accordance with a drawing control signal from the central control device 1. In this case, in FIG.
Two planes, that is, the plane 11 and the second plane 12 indicated by oblique hatching in the lower right are drawn in the drawing memory 2.

In the color pallet 10, display data color information 15 for each color address 14 is written in advance by a color information control signal from the central control device 1. In the color palette 10 in FIG. 3, both the first plane 11 and the second plane 12 store 16 color addresses 14, in other words, display data color information 15 of 16 colors. Is 1 bit for designating a plane and 4 bits for designating a color in the same plane, for a total of 5 bits. Therefore, the display data color address information in FIG. 1 is “0000” per pixel,
Each of the four bits is drawn like “1111”.

In this state, the reading means 2 receives the readout timing control signal from the timing control means 5 and the screen division control signal from the screen division control means 6 from the image memory 17 to the first plane 11 as shown in FIG. The display data color address information is sequentially read out in a form where the two planes 12 are joined at the screen division position, temporarily stored in an internal buffer, and then superimposed while synchronizing with a synchronization control signal from the timing control means 5 to the display means 4. To the means 23. The screen division control means 6 designates a division position by giving a division position control signal from the central control device 1 in advance so as to perform such a reading, and responds to the display position signal from the timing control means 5. A screen division control unit 6 generates a screen division signal that specifies a plane area to be read.

FIG. 2 shows a case where the display screen is divided into left and right. If the display position is on the left side of the division position, plane 11 is designated as a readout area, and if on the right side, plane 12 is designated as a readout area. I do. Note that the central control unit 1 sends the image memory 2 for each plane to the reading means 7 by a plane read control signal.
In advance, the designation of the read area and the number of planes to be read are specified in advance. In FIG. 2, the designation of the number of planes to be read is two.

Next, in the superimposing means 9, a superimposition control signal specified in advance by the central control device 1
The display data color address information of the plurality of planes is superimposed from the reading means 7 in accordance with the vertical order of superposition between the plurality of planes and the color address as the transparent color, and the resulting display data color address information is stored in the color palette 10. Send out.

In FIG. 2, the display data color address information on the left side of the plane 11 divided position and the right side of the plane 12 divided position are output as they are, as indicated by reference numeral 13, without superposition. In the color pallet 10, the display data color address information is referred to the display data color signal previously designated by the color information control signal from the central control device 1 while referring to the screen division control signal from the screen division control means 6. From the timing control unit 5 to the display unit 4 as display data color information.
Are sequentially sent to the display means 4 in synchronization with the synchronization control signal to

In FIG. 2, the screen division control signal from the screen division control means 6 is assigned to the most significant bit of the color address 14 of the color pallet 10, and the display data color address information from the superposition means 9 is assigned to the remaining 4 bits. By assigning, if the display position is on the left side of the division position, the display data color information 15 for the plane 11 in the color palette 10 is assigned.
Is specified. Therefore, FIG. 2 projected on the display means 4
The maximum number of colors that can be simultaneously colored on each of the left and right sides of the divided screen 13 in which the planes 11 and 12 are joined at the division position as shown in FIG. It is possible to secure 16 or more for one plane.

As described above, according to the screen division display device of the present embodiment, the raster scan display position on the display means 4 is changed to which plane area of the divided screen in accordance with the display position control signal from the timing control means 5. Is generated by the screen division control means 6, and when the display data color address information is read from the image memory 2 by the reading means 7, the screen division control signal is transmitted from the timing control means 5. To be used in conjunction with the read timing control signal. Thus, in order to realize the screen division display, the plane 11 and the plane 12 may be joined at the screen division position. As a result, the read time does not increase and the DRA having only one bus as the image memory 2 is used.
Even when an inexpensive general-purpose memory such as M is used, the drawable time can be made the same as that in the case of a single readout plane, and a decrease in drawing speed can be suppressed.

Also, in the color pallet 10, when the display data color address information from the superimposing means 9 is converted into the display data color information, the screen division control signal from the screen division control means 6 is used. If the raster scan display position is on the left side of the division position, the display data color information 15 for the plane 11 in the color pallet 10 can be specified. If the raster scan display position is on the right side, the display data color information 15 for the plane 11 can be specified. The maximum possible number of colors can be secured up to 32, which is more than the number of superimposed planes, here 16 for one plane.

Furthermore, if each plane in the image memory 2 is drawn in advance in a size larger than the divided display size, the central control unit 1 sends the reading means 7 to each of the planes by a plane read control signal. By simply changing the designation of the readout area in the image memory 2, scrolling can be performed for each divided screen, so that it is not necessary to redraw, and it is possible to prevent a decrease in scroll speed when drawing is slow.

In the above embodiment, the display memory color address information of the planes 11 and 12 shown in FIG.
By arranging the display data color information 15 for the plane 11 and the plane 12 for the plane 12 as shown in (1) and specifying the left and right division positions in advance by the division position control signal from the central control device 1 to the screen division control means 6, The screen split display is realized by dividing the screen into two right and left sides. The display data color address information of a plurality of planes is arranged in the image memory 2 and the display data color information of the plurality of planes is arranged in the color pallet 10, respectively. By specifying an arbitrary division position in advance by the division control signal from the central control device 1 in the division control means 6, it is possible to realize screen division display in an arbitrary shape. Even in this case, the reading means 7 only needs to read out the display data color address information corresponding to one plane in which a plurality of planes are joined at an arbitrary screen division position, and has only one bus as an image memory. Even when an inexpensive general-purpose memory is used, it is possible to make the drawing possible time the same as that for a single read plane. Then, the maximum number of colors that can be simultaneously formed is determined by the color palette 10.
Can be secured up to the display data information for a plurality of planes. For example, if the plurality of numbers is 4, 16 × 4 = 64.

The number of planes arranged in the image memory 2 and the number of planes arranged in the color palette 10 need not always be the same. If necessary, the number of the plurality of planes arranged in the color palette 10 may be smaller than the number of the plurality of planes arranged in the image memory 2.
As a result, the amount of display data color information of the color pallet 10 can be reduced to a value that requires the maximum number of colors that can be displayed simultaneously, thereby eliminating waste.

In the above embodiment, the superimposing means 9 does not perform superimposition, in other words, the number of superimposed planes is 1. However, any number of superimposed planes may be used. In this case, the reading means 7 reads the display data color address information for the number of superimposed planes from the image memory 2, and each plane in the superimposing direction constitutes the same as in the present embodiment. Since the display data color address information corresponding to one plane is obtained by joining a plurality of planes at the screen division position, the reading time can be reduced compared to the conventional screen division display using only superimposition, and the screen memory can be saved. Even when an inexpensive general-purpose memory having only one bus as 2 is used, it is possible to increase the drawing speed.

In the above-described embodiment, the display data color address information per pixel is 4 bits. However, the same operation as described above can be performed with an arbitrary number of bits.

[0040]

As described above, according to the screen division display device of the present invention, when reading out display data color address information for a plurality of planes from the image memory by the reading means, a plane read control signal from the central control unit and By adopting a configuration in which reading is performed with reference to the screen division control signal from the screen division control unit in addition to the read timing control signal from the timing control unit, the amount of display data color address information to be read can be minimized. Even when an inexpensive general-purpose memory having only one bus is used as a memory, a decrease in drawing speed can be suppressed.

According to the present invention, when the superimposed display data color address information from the superimposing means is converted into the corresponding display data color information by the color palette,
In addition to the color information control signal from the central control means, by referring to the screen division control signal from the screen division control means, the maximum number of colors that can be simultaneously colored is limited to the number of superimposed planes. And more can be secured.

Further, according to the present invention, the drawing is performed in advance on the plane in the image memory in a size larger than the divided display size, and the plane is controlled by the plane reading control signal from the central control unit to the reading means. By simply changing the designation of the readout area in the image memory for each
Since scrolling can be performed for each divided screen, it is not necessary to perform redrawing, so that there is an effect that a decrease in scroll speed when drawing is slow can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram showing contents of a display screen corresponding to contents of an image memory according to the embodiment of the present invention.

FIG. 3 is a schematic diagram showing the contents of a color palette according to the embodiment of the present invention.

FIG. 4 is a functional block diagram showing an example of a conventional screen division display device.

FIG. 5 is a schematic diagram showing the contents of a screen division display by superimposing two planes corresponding to the contents of an image memory in the related art.

FIG. 6 is a schematic diagram showing the contents obtained by dividing a screen in one plane corresponding to the contents of a conventional image memory.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Central control device 2 Image memory 3 Drawing means 4 Display means 5 Timing control means 6 Screen division control means 7 Reading means 8 Bus arbitration means 9 Superposition means 10 Color palette 11 Plate 12 Plate

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[Procedure amendment]

[Submission date] May 2, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction contents]

Further, in the above embodiment, although the display data color address information per pixel and 4 bits can be implemented to be similar to the case described above be any number of bits.

Claims (1)

[Claims] A central control device; an image memory for storing display data color address information for a plurality of planes; a drawing means for performing drawing on the image memory in response to a drawing control signal from the central control device; Means, a timing control means for outputting a synchronization control signal to the display means, and a screen division for outputting a screen division control signal in response to a division position control signal from the central control device and a display position signal from the timing control means. Control means; display data for a plurality of planes from the image memory in response to a plane read control signal from the central control device, a read timing control signal from the timing control means, and a screen division control signal from the screen division control means; Reading means for reading color address information, the drawing means and the image memory of the reading means A bus arbitration unit for arbitrating the bus; and a superposition unit for outputting the superimposed display data color address information in accordance with the superimposition control signal from the central control unit and the display data color address information number for a plurality of planes from the readout unit. A superimposing means, and superimposing display data color address information from the superimposing means to corresponding display data color information in accordance with a color information control signal from the central control means and a screen division control signal from the screen dividing control means. A screen division display device comprising a color palette for converting and outputting to a display means.