JPS61273584A - Display unit - 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 [Technical Field of the Invention] The present invention relates to a display device that can output predetermined display information to a non-display area of a display device.

(Technical Background of the Invention and Problems thereof) A CRT display device is usually provided with a refresh memory to output necessary display information to a display area for displaying characters and figures. That is, by inputting predetermined information into the refresh memory and outputting it to the display while sequentially scanning it, predetermined characters and figures can be displayed in the display area.

Conventional CRT display devices have no memory for displaying images other than this refresh memory, so areas other than the display area (hereinafter referred to as non-display areas) are
The problem is that the screen remains the same as the background color of the screen, or emit light unconditionally at a constant brightness using an overscan method, making it difficult to see and tiring.

On the other hand, in recent years, in order to make the screen display easy to read, it has become possible to thin out the dots using a certain method and make the CRT tube surface emit light to display the background, and then display information on top of this. Since such a background cannot be displayed in the area, there is a drawback that the screen display becomes unnatural. In order to eliminate these drawbacks, it may be possible to expand the display area to the full screen, but in this case, the corresponding amount of refresh memory would be required, which would increase the price of the entire device. There is a drawback.

(Object of the Invention) The present invention has been made in order to improve the above-mentioned drawbacks, and it is an object of the present invention to provide a display device that can display a background in an arbitrary pattern in a non-display area without providing an extra refresh memory. With the goal.

[Summary of the invention]

In order to achieve the above object, the display device according to the present invention includes a refresh memory that stores first display information to be output to the display area of the display device, and a refresh memory that stores second display information to be output to the non-display area. A pattern memory, a reading means for reading out second display information in the pattern memory by using a raster number that changes in accordance with the display timing as an address input, and a raster number that corresponds to whether it is a display area or a non-display area. and a selector that selects either the refresh memory or the pattern memory and outputs the selected one to the display, and outputs the second display information to the non-display area. This allows a background display of an arbitrary pattern to be displayed in the non-display area, improving visibility.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a block diagram of a display device showing one embodiment of the present invention. The pass line 101 includes a CPU 1 which controls the entire device, a character pattern memory 2 which stores characters and figures to be displayed in the display area, a refresh memory 3 which stores contents to be displayed corresponding to the display area,
A pattern memory 4 for storing a background display corresponding to a non-display area and a control section 5 for controlling display timing, which are newly added according to the present invention, are connected. .

The refresh memory 3 and the pattern memory 4 operate to output their stored information to the selector 6, and the contents of either memory are selected in response to control signals 107 and 108 from the display timing control section 5 and are arranged in parallel and serially. It is transmitted via signal line 104 to converter 7 .

The image information converted into a raster scan signal by the parallel-to-serial converter 7 is transmitted to the display 8 via the signal line 105 and displayed as an image.

Next, the operation of the apparatus shown in FIG. 1 will be explained. Figure 2 shows display 8
This figure shows the structure of the tube surface, which is composed of a display area 30 and a non-display area 40.

First, the operation when displaying normal characters in the display area 30 will be explained. The display information in the refresh memory 3 is controlled by the display timing control unit 5 according to the display timing.
The signals are sequentially read out via control lines (not shown) and read out to the selector 6 through the signal line 102.

Next, the display information is transferred to the parallel-to-serial converter 7 via the signal line 10 in accordance with control signals 107 and 108 from the display timing control section 5.
4, is converted into a dot serial signal, and is sent to the display 8 via the signal line 105 for display.

Note that between the refresh memory 3 and the display 8, the addresses and their display positions are corresponded in advance. Therefore, if the CPU 1 accesses the character pattern memory 2 and writes the read pattern data to a desired address in the refresh memory 3, the character will be displayed at the corresponding position on the display 8.

In general, the start address of the refresh memory 3 is configured to correspond to the upper left corner of the display area 30 of the display 8, so for example, characters stored in the character pattern memory 2 are read from the start of the refresh memory 3 and read out in ABCD.
When written, ABCD is displayed in order from the upper left corner of the display area 3o as shown in FIG.

Next, the operation for outputting display information to the non-display area 40 will be explained. All display information displayed in the non-display area 40 is stored in the pattern memory 4. The display information in the pattern memory 4 is configured so that a raster number that changes in accordance with the display timing is read out as an address input.

3A and 3B are memory maps showing the memory contents of the pattern memory 4, respectively. In this embodiment, the pattern memory is composed of an 8-bit x 8-entry RAM. The RAM has eight entries numbered 0 to 7. Furthermore, the contents of the memory map can be rewritten by sequential access by the CPU 1.

Note that when the memory map shown in FIG. 3(A) is used, a zigzag pattern is displayed in the non-display area 40, and when the memory map shown in FIG. 3(B) is used, a check pattern is displayed.

A 3-bit address signal 106 is input to the pattern memory 4 from the display timing control unit 5, and when the CPU 1 updates the contents of the memory map, the address value specified by CPLJl is input, and at other times, the address signal 106 is input to the display timing. A raster number that changes accordingly is given as an address signal 106.

Note that the arbitration between update and display is well known in this type of memory access conflict processing, so its explanation will be omitted. The raster number of the display timing is given to the pattern memory 4 as an address input, and the pattern data read out as a result enters the selector 6 through the signal line 103. Control signals 107 and 108 are inputted to the selector 6 from the display timing control section 5, display information from the refresh memory 3 is selected in response to the control signal 107, and display information is selected from the pattern memory 4 in response to the control signal 10c8. The display information within is selected and input to the parallel-to-serial converter 7 through the signal line 104.

FIG. 4 shows a timing chart for explaining the operation of the selector 6, in which display information stored in the refresh memory 3 and pattern memory 4 is output to the signal line 104 in response to control signals 107 and 108. It shows how it is done.

Note that the relationship between the display information signal output to the non-display area 40 and the vertical synchronization signal of the display device 8 is also shown in the timing chart, and the vertical synchronization signal is output during the period when the control signal 108 is at a high level.ノ] to be done.

In this way, the display information output to the display area 30 and the display information output to the non-display area 40 by the selector 6 are selectively entered into the display 8, and the display is performed in the same way as in normal character display. be exposed.

(Effects of the Invention) As described above in detail based on the embodiments, according to the present invention, a pattern memory is provided for storing display information to be output to a non-display area, and selection is made between the pattern memory and the refresh memory contents. Therefore, any pattern of background display can be made into a hidden area.

This makes it possible to diversify screen displays without using a large capacity refresh memory, resulting in a screen that is easy to view and that does not cause fatigue even when viewed for a long time.

Furthermore, if the pattern memory is configured with RAM, the CPU
Since it can be rewritten, a variety of screens can be configured.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a display device according to an embodiment of the present invention, FIG. 2 is a diagram showing a snow surface display configuration of the display device used in this invention, and FIG. 3 is a pattern used in the present invention. A memory map showing the contents of the memory, and FIG. 4 is an operation timing chart for explaining the operation of FIG. 1. 2...Character pattern memory, 3...Refresh memory, 4...Pattern memory, 5...Display timing control section, 6...Selector, 8...Display device, 30.
...Display area, 40...Non-display area, 106...
-Address signal, 107.108...control signal. Figure 1 Figure 2 Address l06m Pattern memory contents 3rd
Figure 4

Claims (1)

[Claims] 1. A refresh memory that stores first display information to be output to the display area of the display device, a pattern memory that stores second display information to be output to the non-display area, and a display reading means for reading out the second display information in the pattern memory using a raster number that changes in accordance with timing as an address input; and refreshing the raster number according to whether the raster number is in a display area or a non-display area. A display device comprising a memory and a selector for selecting one of the pattern memories and outputting it to the display device, and outputting the second display information to the non-display area. 2. The display device according to claim 1, wherein the pattern memory is constituted by a memory whose contents can be updated.