JPS6359624A - Display device - Google Patents

Abstract

PURPOSE:To eliminate the need of generation of a program which performs a complicated display data processing of each bit, by reading and displaying display information stored in a corresponding display information storage means in accordance with read-out information. CONSTITUTION:A host 50 sends display data to be displayed on a CRT 19 to an interface control circuit 1, and the interface control circuit 1 stores this display data in designated one of display memories A...D. The read start position in a display memory 2 of display data to be displayed on the CRT 19 is designated. Designating information of the display memory to be selected on the display screen of the CRT 19 is sent from the host 50. The interface control circuit 1 stores designating in formation of the display screen in an indicated data memory 3. The interface control circuit 1 calculates the read start position of display data in the display memory in accordance with this instructed data and stores it in an Xht register 4 and a Yht register 4, and the display processing is executed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a display device that selects arbitrary screen data from a plurality of display screen data on the same display screen and displays it at an arbitrary position on the display screen. It is something.

[Prior Art] Conventionally, in this type of multi-window display device, in order to select and display multiple screens, a central processing unit, which is installed in front of the display device and performs overall processing of display data, must All complicated display control processing such as screen data management and screen selection was performed, and the display data was output to the display device for display. Particularly in the bitmap type, complicated processing is performed for each display dot.

[Problems to be solved by the invention] Therefore, since the central processing unit needs to process display data for each bit, manage multiple screens, etc., the processing load on the central processing unit increases. However, there was a drawback that the display speed decreased.

Another problem is that a complicated data processing program must be created in order to perform the above-described display data processing. For this reason, a large storage area in the main memory, which is exclusively used by the program, is required.

[Means for Solving the Problems] The present invention has been made for the purpose of eliminating the above-mentioned problems, and includes the following configuration of the present embodiment as a means for solving the above-mentioned problems.

That is, a display means for displaying information, at least two display information storage means having a storage capacity of display information for one screen of the display means, and one display information storage means for each display position in the display means. a storage area storage means for storing information specifying a display information storage area for each display information storage means; The apparatus includes a display area storage means for storing information instructing a display means display area in which instruction information is to be displayed, and a display control means for displaying selected display information on the display means according to the stored contents of each of these storage means.

[Operation] In the above configuration, the display control means reads the specified information from the specified information storage means, reads out the corresponding storage information of the storage area storage means and the display information storage means according to the read information, and responds according to the read information. The display information stored in the display information storage means is read out and displayed on the display means.

This makes it possible to reduce the processing load on the central processing unit and the like, and to provide a display device that eliminates the need to create a program that performs complicated bit-by-bit display data processing.

[Example] Hereinafter, an example according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment according to the present invention. In the figure, 1 is an interface control circuit, and the interface control circuit 1 is an interface between a host 50 that is a display information supply source of a central processing unit, etc. In addition, it stores or sends data to each part of the present embodiment according to a received signal from the host 50.

A display memory 2 stores display information L9 for each display pixel of a display screen of a CRT display device (hereinafter referred to as rcRTJ) 19, and is provided with display memories A to D for four screens. Reference numeral 3 designates an instruction data memory that stores instruction data for instructing from which display memory A to D the display data to be displayed for each display position of the CRT 19 is to be read out; 1og2 (display data screen);
That is, this embodiment has a storage capacity for two screens. 4 is an xht register, and 5 is a Yht register, which instructs which display position on the CRT 19 to select and display one of the display memories A to D.
This is a register that holds direction data. Also 6 is Xut
Register 7 is a Yut register, and display memory A-
This is a register that holds X-direction and Y-direction data that indicates the start address position of the display information storage area to be displayed on the CRT 19 in D.

These register groups (designated register groups) 4 to 7 are provided in groups A to D, each corresponding to four screens of display data A to D.

A clock generating circuit 8 generates a clock signal corresponding to the scanning speed of the CRT 19. 9 is a main scanning counter, and 10 is a sub-scanning counter, which indicates the display scanning position of the CRT 19. 11 detects the display state of the CRT 19 from the contents of the main scanning counter 9 and the sub-scanning counter 1o;
Each display register group of Xu, Yu, Xh, Yh, DTX (
12 to 15) are display position control circuits that select and store the contents held in designated register groups 4 to 7; 12 is an Xu register; and 13 is a Yu register; It holds X-direction and Y-direction data that indicates whether to read from the memory. Further, 14 is an xh register, and 15 is a Yh register, which are located in the X and Y directions at the beginning of the display data storage area in the display memory 2 specified by the Xu register 12 and Yu register 13 while being displayed on the CRT 19. Holds address data. Further, 15 is a DIX register, which holds storage information of an address corresponding to the current display position of the CRT 19 in the instruction data memory 3.

17 refers to the values of the display register groups 12 to 16 according to the contents of the main scanning counter 9 and the sub-scanning counter 10, reads display data to be displayed at the current display position of the CRT 19 in the display memory 2, and displays the display control circuit 18. 18 is a display control circuit that controls display of display data from the readout control circuit 17 at a display position on the CRT 19 specified by the contents of the main scanning counter 9 and the sub-scanning counter 10.

Further, 20 is a control signal line (r/W) for controlling reading/writing of data with respect to the data bus 22, 21 is an address bus (AB), and 22 is a data bus (DB).

The display control of this embodiment having the above configuration will be explained below with reference to the flowcharts of FIGS. 2 and 3.

2 is mainly a control flowchart in the interface control section 1 of this embodiment, and FIG. 3 is a display control flowchart mainly in the display position control circuit 11 and readout control circuit 17.

To display on the CRT 19, first, as shown in step S1 in FIG. is stored in one of the designated display memories A to D. Next, in step S2, the reading start position in the display memory 2 to be displayed on the CRT 19 is designated.In the interface control circuit 1, this data is stored in Xut in step S3. Register 6 and Y
Set in ut register 7. And the next step S
At step 4, the host 50 sends designation information of the display memory to be selected on the display screen of the CRT 19. Therefore, the interface control circuit 1 stores this display screen designation information in the instruction data memory 3 in step S5. When this specification from the host 50 is sent in bit units, this data is stored as is in the instruction data memory 3, and when specifying an area, it is converted into bit map data in bit units by the interface control circuit 1, and then the data is stored in the instruction data memory 3. Store. Then, in step S6, the interface control circuit 1 calculates the reading start position of the display data in the display memory 2 from this instruction data, and in step S7, this calculated position data is
Store in register 4 and Yht register 5. Since the preparation for display is now complete, display processing is executed in step S8, and if there is a request to change the display contents from the host in step S9, the display internal characters are changed from step S1. Note that from now on, among steps 31 to S7, only the processes that need to be changed are changed.

For example, if only a part of the display position on the CRT 19 is to be changed, only steps 54 to S7 are performed, and if only the display data in one display data area of the display memory 2 is to be changed, only steps S2 and S3 are performed. All you have to do is execute.

A simplified diagram of the display data storage state in the display memories A to D at this time is shown in FIGS. 4(A) to 4(D).

4(A) shows display memory A, FIG. 4(B) shows display memory B, FIG. 4(C) shows display memory C1, and FIG. 4(D) shows display memory D. For the sake of simplicity, the memory is shown for a total of 25 pixels, 0 to 4 in the X direction and 0 to 4 in the y direction.

Each screen originally stores the values ``1'' and 0, but
For clarity of explanation, display memory A is written as t0 content: °"A", display memory B is "B", and display memory C is °゛C.
The display memory D is indicated by the value 'D'. Here, the shaded area indicates the display area to be displayed on the CRT 19.

A storage example of the instruction data memory 3 is shown in FIG. 5. In FIG.
indicates that each is specified. The storage contents of the designated register groups 4 to 7 when the instruction data memory 3 has the contents shown in FIG. 5 and the shaded areas of the display memory 2 shown in FIGS. Figure 6 (A)
- Shown in (D). The position indicating the beginning of the display area on the display screen of the CRT 19 specified by the instruction data memory 3 is from the display memory A at ``3°'' in the X direction and 0° in the Y direction.
Display memory B is ``1°'' in the X direction and ``1'' in the Y direction, display memory C is ``O'' in the X direction and 3° in the Y direction, and display memory D is ``0'' in the X direction and ``0'' in the Y direction. from "°0", and the contents of xht register 4 and Yht register 5 are the 6th
The result will be as shown in Figures (A) and (B).

Similarly, if the display data area to be displayed in each display memory 2 is the area shown with diagonal lines in FIGS. "2 Pa, Display memory B is in the X direction "o", Y direction is "1", display memory C is in the X direction "O', Y direction is "1", display memory D is in the X direction "2", Y direction “2”, and the contents of Xut register 6 and Yut register 7 are 6th (C) and (D).
It will look like this.

Next, control of the display processing in step S8 will be explained with reference to the flowchart of FIG.

First, in step S20, the display position control circuit 11
reads the counter values of the main scanning counter 9 and the sub-scanning counter 10, that is, the current (or future) display position on the display screen of the CRT 19.

Then, in the next step S21, data is read from the address corresponding to the display position in the instruction data memory 3. now,
Main scanning counter 9 is "3", sub-scanning counter is "2"
For example, the contents of the instruction data memory 3 are the fifth
This is the position indicated by a circle in the figure, and "1" is stored here, which means that display memory B is selected.

In the next step S22, it is checked whether the display memory data is the same as the contents of the instruction data memory 3 read last time. Here, if it is the same as the previous time, the process advances to step S25.

If the data is different from the previous data, the contents of the instruction data memory 3 are written to the DIX register 16. Then, in the following step S24, the values of the position instruction registers 4 to 7 corresponding to the indicated display memory are set in the display register group.

Here, (3, 2) of the instruction data memory 2 shown in FIG.
When is selected, display memory B is specified,
Position specification registers Xht4, Yht5. Xut6. Yu
The corresponding value of each register in t7 is (1, i, o, i).

Therefore, the display position control circuit 11 controls this (1, 1, 0
, 1) are displayed in the register group xh14, Yh15, Xu1
2. Set in each register of Yu13. Then, in the subsequent step 325, the first-first-out control circuit 17 calculates the read address position in the display memory 2 from the values of the display register group 12-15.

This is (current display position) - (display start position) + (readout start position), that is, (value of main scanning counter 9 or sub-scanning counter 10) - (value of xh register 14 or Yh register 15)
+(value of Xu register 12 or Yu register 13).

In the above example, X direction = (main scanning counter value) - (xh register value)
+Xu register value) =3-1+0=2 Y direction・(Sub-scanning counter value)-(yh register value)
+Yu register value) = 2 - 1 + 1 = 2, and (X, Y) = (2, 2) of display memory B, that is, the address of the position indicated by ◯ in Fig. 4 (B) is calculated.

Then, the process proceeds to step S26, where the display data is read from the address of the display memory 2 calculated in step S25,
In the next step S26, this is displayed on the CRT 19 and the process returns.

Then, when the contents of the main scanning counter 9 and the sub-scanning counter 10 change, the process returns to step S20, and the next display data is read and displayed.

An example displayed on the CRT 19 in this manner is shown in FIG.

As explained above, according to this embodiment, the host 50 simply outputs the display data and display position to the display grid once, and then divides the display screen of the display device by controlling the display device. Multiple display data can be displayed.

In the above description, a CRT display is used as the display 19, but it is of course possible to use another display such as an LCD display instead.

Furthermore, in this embodiment, display memory for four screens is provided to enable split display of four screens. Display control can be performed on as many screens as possible.

For example, in the case of two-screen control, the above configuration can be expanded.

As is clear from the above description, according to this embodiment, when performing a process generally called mouse wint,
On the host side, just set a simple value on the display device,
Since the rest of the display control can be automatically performed on the display device side, a special effect can be obtained in that complex multi-window display control can be performed extremely easily.

[Effects of the Invention] As described above, according to the present invention, so-called multi-window display control can be automatically performed in a display device by only having N configurations.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment according to the present invention, FIG.
FIG. 3 is a display control flowchart of this embodiment. FIGS. 4(A) to (D) are diagrams showing storage examples of the display memory of this embodiment. FIG. 5 is a storage example of the instruction data memory of this embodiment. FIGS. 6A to 6D are diagrams showing examples of the contents of the position designation register of this embodiment, and FIG. 7 is a diagram showing an example of display on a CRT. In the figure, 1...interface, 2...display memory,
3... Instruction data memory, 4... xht register,
5...yht register, 6...Xut register, 7
...Yut register, 9...Main scanning counter, 10
. . . Sub-scanning counter, 11 . . . Display position control circuit,
12...Xu register, 13...Yu register, 1
4Xh register, 15...Yu register, 16...
DIX register, 17...read control circuit, 18...
Display control circuit, 19...CRT. Patent applicant: Canon Co., Ltd. Figure 4 ``DE=]=IE]

Claims (3)

[Claims] (1) A display means for displaying information, at least two display information storage means having a storage capacity of display information for one screen of the display means, and a display information storage means for each display position in the display means. designation information storage means for storing information specifying one of the display information storage means; storage area storage means for storing information indicating a display information storage area for the display means for each of the display information storage means; display area storage means for storing information instructing a display means display area in which instruction information instructed by the means should be displayed; and display control for displaying selected display information on the display means according to the storage contents of each of these storage means. A display device comprising: means. (2) The display control means reads the specified information from the specified information storage means, reads out the corresponding storage information of the storage area storage means and the display area storage means according to the read information, and stores the corresponding storage information in the display information storage means according to the read information. 2. The display device according to claim 1, wherein stored display information is read out and displayed on a display means. (3) The display device according to claim 1 or 2, wherein the storage area storage means and the display area storage means store readout start position information of each area.