JPS61240286A - Monitor display control system - 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] [Summary] In a display device which is equipped with an external monitor device and whose display contents can be changed by an input means, when display data is changed by the input means, only the screen memory for the display device is changed first. However, when the change is completed, the contents of the screen memory are transferred to the screen memory for the monitor device, and the contents that are being changed are not displayed on the monitor device.

[Industrial application field]

The present invention relates to a display device that is equipped with an external monitor device and whose display contents can be changed using an input means such as a keyboard, and in particular, the present invention relates to a display device that is equipped with an external monitor device and whose display contents can be changed using input means such as a keyboard, and in particular, it is possible to quickly change the display contents of a monitor device that displays the same as or a part of the display device. This invention relates to a possible monitor display control method.

2. Description of the Related Art With the development of an information society, various display devices have been developed and put into practical use, and display devices are used, for example, to provide departure and arrival guidance for aircraft, trains, and the like. These display devices are connected online to a computer system and display various information processed by the computer system.

In this case, multiple monitor devices installed outside the display device are generally connected to the display device and display the same content or part of it as the display device, and the general passenger can see the content displayed on the monitor device. There is.

Therefore, when there is a change in the content displayed on the monitor device, it is necessary that the content in the process of being changed is not displayed.

[Conventional technology]

FIG. 2 is a block diagram showing an example of a display device equipped with a conventional monitor device.

A keyboard 2 and a monitor device 3 are connected to a display device 1 . The processor 4 then reads the program stored in the ROM 6 and operates. After passing through the interface circuit 7,
Display data is sent from a host device such as a computer system.

The processor 4 stores this display data in the RAM 5 and transfers one screen worth of display data to the screen memory 8. The video circuit 9 scans and reads the screen memory 8, converts it into a video signal, sends it to the display unit 10 for display, and
It is also sent to the monitor device 3 and displayed.

A working display device connected to a computer system online! ! ! .

However, due to a failure etc., the display device 1 was switched offline and
When changing the display contents by inputting changes from the keyboard 2 connected to the operator, the operator inputs the contents to be changed by operating the keyboard 2 while looking at the display on the display unit 10.

The processor 4 sequentially updates the contents of the RAM 5 based on input from the keyboard 2, and also sequentially changes the display data of the screen memory 8. Therefore, the contents of this change in progress are also displayed on the monitor device 3.

[Problem that the invention seeks to solve]

As described above, in the conventional display device, the contents that are being changed are also displayed on the monitor device at the same time, so there is a problem that passengers may see the changed contents and misrecognize the information.

In view of these problems, the present invention displays the display contents before correction on the monitor device until the display data of the display device is corrected, and when the display data of the display device is corrected, the display contents are displayed on the monitor device. The purpose is to display the displayed content.

[Means for solving problems]

FIG. 1 is a block diagram of a circuit showing one embodiment of the present invention.

FIG. 1 shows that the display device 1 of FIG. 2 is provided with means for transferring at least part of the contents of the screen memory 8 to the screen memory 12, such as a DMA (direct memory access) circuit 11.
, a screen memory 12 and a video circuit 13 are added, and a monitor device 3 is connected to the output side of the video circuit 13.

The processor 4 changes the contents of the screen memory 8 based on the input from the keyboard 2, but does not change the contents of the screen memory 12, and when the contents change is completed and there is an instruction from the keyboard 2, the DMA circuit 11 The screen memory 8 is activated to transfer the contents of the screen memory 8 to the screen memory 12 at high speed, and display data is updated at high speed.

[Effect]

By configuring as above, the operator can
0 is displayed, and when the modification of the displayed data is completed, the contents of the screen memory 8 are transferred to the screen memory 12 by pressing the send key used online, for example, and the contents of the screen memory 8 are transferred to the screen memory 12, and Update the display contents of 3.

Therefore, since the contents that are being changed are not displayed on the screen memory 12, passengers do not see the contents that are being changed, and normal display data is always displayed.

〔Example〕

In FIG. 1, since the processor 4 has shifted to offline operation, it validates the data input from the keyboard 2, changes the data in the RAM 5, and also changes the display data in the screen memory 8.

However, the information input period from keyboard 2 is screen memory 1.
The display data of No. 2 is not changed, and the display data before modification is displayed on the monitor device 3 by a video signal sent from a video circuit 13 that scans and reads out the contents of the screen memory 12.

When, for example, a send key used when online is pressed to indicate completion of modification from the keyboard 2, the processor 4 determines this as an activation signal for the DMA circuit 11 since the processor 4 is offline, and activates the DMA circuit 11.

Under the control of the processor 4, the DMA circuit 11 transfers the entire contents of the screen memory 8 to the screen memory 12 when the monitor device 3 is displaying the same content as the display section 10, and the monitor device 3 transfers the entire contents of the display section 10. When only the part necessary for the passenger is displayed, only that part is transferred to the screen memory 12 and the display data is rewritten.

In general, the speed of DMA is that it is possible to transfer one character in approximately the same time as the access time of the memory being used, and if a memory with an access time of several hundred n3 is used, it would be necessary to transfer the display contents of about 2000 characters. Completed in less than 2 ma.

Generally, monitor devices are refreshed at a frequency of several tens of Hz, so the time required to rewrite the screen memory 12 can be almost ignored. Therefore, the display contents of the monitor device 3 always appear to be displaying normal information.

It goes without saying that the transfer from the screen memory 8 to the screen memory 12 may be performed through the processor 4.

〔Effect of the invention〕

As described above, the present invention can prevent the content being changed from being displayed on the monitor device when display data is modified using the keyboard on the display device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a circuit showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a conventional display device. In the figure, 1 is a display device, 2 is a keyboard, 3 is a monitor device, 4 is a processor, 5 is a RAM,
6 is ROM. 7 is an interface circuit, 8.12 is a screen memory, 9 and 13 are video circuits, 1
0 is a display section, and 11 is a DMA circuit. 1M-

Claims (1)

[Scope of Claims] In a display device (1) which is provided with an external monitor device (3) and whose display contents can be changed by an input means (2), a first screen memory (12) dedicated to the monitor device (3) is provided. and means (11) for transferring the contents of a second screen memory (8) dedicated to the display device (1) to the first screen memory (12).
), and when the display contents are changed by the input means (2), after changing the contents of the second screen memory (8), the transfer means (11) is activated and the second screen memory ( 8) A monitor display control method characterized in that all or part of the above is transferred to a first screen memory (12).