JPS5931714B2 - display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display device that can easily move information displayed on a screen.

Recently, cathode ray tubes (hereinafter referred to as CRTs) have become popular.

) communication between computers and operators has become smoother. Recently, the displayed content is not just letters and numbers, but also a system diagram showing the entire process, and the process is operated and controlled while looking at it. In this case, in order to be able to see the entire process, the screen must be displayed on a screen far larger than the display capacity of one CRT. Conventionally, the solution to this problem was to display the information on multiple CRTs, or to store the entire information as a virtual screen in an external storage device, and then extract and display the part the operator wanted to see. If you wanted to look around, you could move the display on the CRT up, down, left, and right. The former method has many problems such as being very expensive and the program is complicated, so the latter method is currently being used more often. The following method is used to move the latter screen vertically and horizontally. First, according to the movement command from the computer, move smoothly in dots or raster units in the specified direction. During this time, data for one newly displayed row or column at the edge is received from the computer, and the above series of steps is performed. This method reports the completion to the computer when the movement in units of dots or raster units is completed, and then shifts the base point address register for reading the refresh memory from the computer by one row or column. Here, the timing at which the end of movement was reported to the computer was at the beginning of the vertical blanking interval. When the computer system was not so large as in the past, the response from the computer to rewrite the base address register was immediate and in most cases occurred during the same vertical retrace interval that reported the end, which caused problems. Screen movement was smooth and smooth.
However, with the recent rapid increase in the amount of information, the load on computers has increased, and CRTs that can move screens on a single computer have also increased.
There are many cases where multiple units are hanging, and as a result, the response of rewriting the base address register of the computer is often delayed, and because this is done while the screen is displayed past the vertical retrace interval, the screen may move up, down, left, or right in the middle of the screen. Problems have started to appear where the robot is misaligned and cannot move smoothly. An object of the present invention was conceived to solve the above-mentioned problems, and it is an object of the present invention to provide a display device that realizes smooth screen movement without being affected by computer load.

The feature of this device is that a one-stage buffer register for receiving data from the computer is provided before the base address register, and the data in this buffer register is transferred to the base address register during the vertical retrace interval.

This prevents the base point address register from being rewritten during display, allowing smooth screen movement. FIG. 1 is a drawing showing one embodiment of the present invention.

First, the operation of each part of the embodiment will be explained. Reference numerals 1 and 10 indicate registers in which base point address data 2 from an external computer 500 is stored in one role by a set signal 3.

20 is a flip-flop which remembers that the base address data set signal has become ``1'' (that is, the designation of rewrite 3 has come) and is set by writing to the base address; , as the signal 21 indicating the vertical retrace interval becomes "1", the output becomes 81" and the base point address register 40,
50 is a two-input AND gate that generates a data set signal to 50.

40 and 50 are base point X address registers and Y base point address registers that determine the reading start address of the refresh memory, and can be rewritten only by the computer.

Reference numeral 60 denotes an X address counter that counts up sequentially using a clock signal 61 with a one-character period starting from the base point be.

80, 90 are display address signals 62, 72 for repeatedly giving information to the CRT14O, and address signals 81, 8 for exchanging data between the CPU and the display device.
2 to perform the switching. This is a Y address changeover switch.

100 is a refresh memory that stores display information, display color, etc. for one screen;
An address signal from 0 is used to read the contents of that address or write new data to that address.

Reference numeral 110 denotes a character generator, which generates a corresponding character pattern signal based on data read out from the refresh memory 100.

120 is a parallel-to-serial converter that converts the character pattern signal from the character generator 110 into a serial video signal; 13;
0 is a video signal support circuit, and refresh memory 1
The above video signal is converted to a CRTl by the color signal from 00.
This is a video output circuit that controls which of the 4O electron guns is output to, and also mixes horizontal and vertical synchronizing signals.
It is sent to RTl4O.

140 outputs an electron beam from an electron gun energized by a video signal in accordance with horizontal and vertical synchronization signals.
This is a cathode ray tube (CRT) that scans and displays information on its fluorescent surface.

Next, the operation will be explained. When the base address set signal 3 from the external computer 500 becomes "1", the base address data 2 is set in the registers 1 and 10, and the flip-flop 20 is set.

Then, when the vertical blanking interval signal 21 becomes "1", the output of the gate 30 becomes "1" and the base point data is transferred to the register 1.
, 10 to the base address X, Y registers 40, 50, and screen movement has been performed. Since this operation is in the vertical retrace section, smooth movement is performed without screen disturbance. Unless the base address data set signal 3 becomes "1", the base address does not change and the screen remains fixed. It should be noted that any display device other than a CRT may be used as long as it is of a raster format.

Furthermore, the rewriting command can be applied even if it is issued from within. For example, this is the case when a microcomputer is used in a display device. As explained above, by providing a buffer register and rewriting the base address in the vertical retrace section, smooth screen movement can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS The figure shows an embodiment of the present invention. 500...external computer, 1,10...
Registers, 40, 50... Base address register, 100... Refresh memory.

Claims (1)

[Scope of Claims] 1. A refresh memory that stores information for a display screen, a base address register that outputs a read start address of the refresh memory, and a base address register that outputs the read start address of the refresh memory, and a system that reads information in the refresh memory starting from the address of the base address register. A means for sequentially reading the information, a means for forming display information based on the read information to obtain a video signal, and displaying the video signal on a display section using horizontal and vertical synchronization signals, and the base point A buffer register is provided in the preceding stage of the address register, and when the base point address is rewritten by a rewrite command, the base address to be rewritten is stored in the buffer register, and the base point is stored in the buffer register during the vertical retrace interval. A display device in which an address is written in the base address register, and information is read and displayed from a refresh memory using the base address of the base address register as the first address for subsequent display on the display section. 2. The display device according to claim 1, wherein the rewriting command is a command from an external computer. 3. The display device according to claim 1, wherein the display section is formed of a CRT.