JPS594708B2 - Display screen movement control device - Google Patents

Description

[Detailed Description of the Invention] The present invention sets modification information on a display counter.
The present invention relates to a screen movement control device that allows the display location of the screen of a display device to be moved arbitrarily.

The display age of a conventional display device is controlled by transferring the contents 35 of the refresh memory of the CRT display.

This method has the disadvantage that it takes time to read and write all of the screen data, and it also requires a lot of hardware to transfer the screen data.

Furthermore, there is another conventional display position FbI leg as shown in FIG.

Column designation counter 1 and row designation display counter 2 are provided with modification circuits 3 and 4, respectively, and these modification circuits convert the output information of column designation display counter 1 and row designation display counter 2 into the contents of modification registers 5 and 6. It is modified accordingly to obtain the actual line specification information.

According to this method, since the modification circuits 3 and 4 are further provided on the output side of the display counters 1 and 2, the delay time from the input timing of the count clock signals 7 and 8 becomes large. . In addition, the actual column designation information or row designation information is sometimes missing because the time point at which the information is counted is uncertain due to variations in delay time including modification circuit elements. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned conventional drawbacks, and to provide a screen movement control device that allows a display screen to be moved to any position and direction by simply changing the contents of a modification register. .

The screen movement control device according to the present invention includes, in addition to a horizontal counter and a vertical counter synchronized with screen display repetition, a display counter configured as a repetition counter up to the maximum number of characters required for display in terms of rows or columns,
The contents of this display counter are set from other modification registers at the starting point where the screen scanning beam enters the displayable area. By doing so, the addressing of the screen display and the refresh memory is of a relative addressing type, that is, for movement in any direction, the row and column counters can be modified to manage the address relative to the current position. FIG. 2 is a block diagram showing an embodiment of the present invention. In FIG.
01 clock signal.

Then, this count up signal is sent to the character string counter 10.
This becomes the clock signal line 103 of No. 2. string counter 10
The count-up signal No. 2 serves as a horizontal synchronizing signal line and also serves as a clock signal for the character dot row counter 104. The count-up signal line 105 of the character dot row counter 104 is also used as a clock signal for the character row counter 106. The count-up signal line of the character line counter 106 becomes a vertical synchronization signal line. These output respective count signals, which are not shown in FIG. 2, but are used as basic signals for various signals for display. FIG. 3 shows an example of a display screen. Is the display movement control according to the present invention not performed here?
Alternatively, a case will be explained in which the contents of the modification register are zero. On the display screen 200, a character string number 201 indicates the horizontal coordinate of each character, and a character line number 202 indicates the vertical coordinate of each character.

Further, each character is composed of a dot matrix, and the respective numbers of the character dot column 203 and the character dot row 204 are shown. For example, in the example shown in FIG. 3, one character is composed of 7 dots horizontally and 8 dots vertically. In this case, the raster scan starts from the 0th dot, 0th bit row of the character in the 0th column and 0th row, and scans to the right, and when this row is completed, the scan moves to the row below it and is sequentially scanned. Raster scan will be further explained based on drawings. FIG. 4 is an explanatory diagram for explaining raster scanning.

As shown in the figure, there is a raster-scanned scanning line 207 on the display screen 200, and this scanning line 207 has a sawtooth waveform as shown in FIG. It is.

The time t1 of the horizontal deflection signal 208 indicates a scanning period in the horizontal display direction, and the next time T3 is a horizontal retrace period. The range that can be displayed on the display screen 200 is a section L, which is a period of time T2 as indicated by the horizontal deflection signal 208. In the figure, J is the starting point of horizontal scanning, and K is the ending point of scanning. Similarly, vertical deflection signal 2
09 uses a sawtooth waveform as shown in FIG. 4 with a relationship between vertical deflection displacement V2 and time t, time Tll is a vertical scanning period, and time T33 is a vertical retrace time. The displayable range in the vertical direction is a period of time T22 from P to Q in the figure, where P indicates the starting point and Q indicates the ending point. The timing of the start point J of the horizontal scan shown in FIG. 4 corresponds to the signal generated on the count output line 107 of the character string counter 102 in FIG. 2, and the signal line indicates the start point of the screen display range of the horizontal scan. becomes. Similarly, the count output line 108 becomes a signal line corresponding to the end point K. In addition, the count output line 10 of the character line counter 106
Reference numeral 9 indicates the timing of the starting point P in the vertical direction, and indicates a count output line 110 & tower point, which are signal lines indicating the starting point and ending point of the vertical scanning surface display range, respectively. As shown in FIG. 2, the column designation display counter 111 is counted by the same clock signal line 103 that is input to the character string counter 102, and is set by the start point signal line 107.
It is. Further, the modification register 112 stores the data set by the set signal line 107. Here, if the number of displayed characters in the horizontal direction is n characters as shown in FIG. 3, then n characters are displayed during the period of time T2 shown in FIG. 4.

The display counter 111 is controlled by the clock signal line 103.
This is a repetition of O to (n-1) with a period of n. That is, the display counter output is returned to zero by the clear signal line 114 at the same time as the number n of characters is detected by the coincidence detection circuit 113. The horizontal display position is automatically controlled by setting the contents of the modification register 112 every time the display counter 111 performs such an operation at the starting point J, that is, at the time of a modification command. On the other hand, a display counter 115 for specifying a line is counted by the same clock signal 105 that is input to the character line counter 106, and a set signal is manually input via a starting point signal line 109.

Further, a modification register 116 is provided in which data to be set in the display counter 115 via the set signal line 105 is placed. If the number of displayed characters in the vertical direction is m characters as shown in FIG. 3, the display is performed during a period of time T22 from the starting point P to the ending point Q in FIG.

The display counter 115 is controlled by the clock signal line 105.
The number of characters from 0 to (m-1) is counted and output. This display count is repeated with a period of 0 to (m-1). That is, the counter output of the display counter 115 enters the coincidence detection circuit 117, and at the same time when the number m of characters is counted, the display counter 115 is cleared to zero by the clear signal line 118 which outputs a clear signal. As a result, counting starts again from zero. The vertical display position is automatically controlled by setting the contents of the modification register 116 through the signal line 109 each time the display counter 115 that performs such an operation is at the starting point P, that is, at the time of a modification command. Ru. The above-mentioned display counter 11
The output signals of 1 and display counter 115 are the actual column designation report and the actual row designation information, respectively, and are sent to, for example, a refresh memory or the like. Next, a means for outputting a signal for validating the display (indicating the displayable range) will be described below.

Flip-flop 119 is set by start point signal line 107 and reset by end point signal line 108. The output line 120 to which the signal from the flip-flop 119 is output outputs a signal between the starting point J and the ending point K shown in FIG. Further, the flip-flop 121 is set by the start point signal line 109 and is reset by the end point signal line 110. An output line 122 to which the signal from the flip-flop 121 is output is a signal between a starting point p and an ending point Q shown in FIG. When the above-mentioned output lines 120 and 122 are ANDed by an AND gate 123, the resulting signal becomes a signal indicating the displayable range of the display.

This signal is used to switch the display output line and becomes a display on signal. With the above configuration, no matter what value the display counters 111 and 115 have, they cannot be displayed outside the displayable range shown in FIG. 4 (horizontal direction between J and K and vertical direction between P and Q). It will never be done.

This results in a display screen with n characters in the horizontal direction and m characters in the vertical direction, and the display screen can be moved according to the contents set in the modification registers 112 and 116, respectively. Third
In explaining the figures and FIG. 4, the case where the horizontal direction scan is performed in the vertical direction has been described, but conversely, the case where the vertical direction scan is performed in the horizontal direction can be performed in exactly the same way.

Furthermore, even if the raster scan is performed in units of character dots as shown in Figures 3 and 4, or if the inside of the characters is completed and displayed character by character using another display method, , if the scanning direction of each character unit is the same as in the embodiment of the present invention, the same effect can be obtained with a similar device.

As is clear from the above, according to the present invention, not only can the actual row and column designation information be obtained as is with the count timing without including a delay element in the output of the display counter, but it can also be configured with a minimum amount of hardware. There are advantages that can be achieved.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional screen transfer platen control device, Figure 2
FIG. 3 is a block diagram showing an embodiment of the present invention, FIG. 3 is an explanatory diagram showing a screen display method, and FIG. 4 is an explanatory diagram explaining the setting and counting timing of a display counter according to the present invention. Explanation of symbols, 100... Vibrating circuit, 102...
...Character string counter, 106...Character line counter, 112,116...Modification register, 1
11,115...Display counter, 119,12
1...Flip-flop, 123...゜AND circuit.

Claims (1)

[Claims] 1. A character string counter that obtains a horizontal synchronization signal and a signal indicating a valid period of the horizontal synchronization signal based on a clock signal, and a vertical synchronization signal and a signal indicating a valid period of the vertical synchronization signal based on the horizontal synchronization signal. In a screen movement control device for a display that performs display using a raster scan method, the device is equipped with a character line counter that obtains a signal indicating the number of columns; a modification register that stores modification information for modifying columns or rows, and a maximum number of columns displayed on the screen The contents of the above-mentioned modification register are set at the time of a modification command in each cycle, and the output signals obtained from the above-mentioned string or character line counter are sequentially output using the contents of the set register as the initial value. A display counter configured to perform addition counting, and detecting the maximum number of columns and rows displayed on the screen from the output of the display counter and clearing the display counter in order to obtain modified row designation information and column designation information. A screen movement control device for a display, comprising: a detection means for detecting; 2. A character string counter that obtains a horizontal synchronization signal and a signal indicating a valid period of the horizontal synchronization signal based on a clock signal, and a character string counter that obtains a signal indicating a vertical synchronization signal and a valid period of the vertical synchronization signal based on the horizontal synchronization signal. In a screen movement control device for a display that performs display using a raster scan method, it is equipped with a row counter; a modification register that stores modification information for modifying columns or rows, and a counter that counts the maximum number of columns and rows displayed on the screen. The contents of the modification register are set at the time of a modification command in each cycle, and the output signals obtained from the character string or character line counter are sequentially added and counted using the contents of the set register as an initial value. a display counter, a detection means for detecting the maximum number of columns and maximum rows displayed on the screen from the output of the display counter and clearing the display counter in order to obtain modified row designation information and column designation information; The above-mentioned column designation information and row designation information are used only during a time period determined based on a signal indicating the valid period of the horizontal synchronization signal from the character string counter and a signal indicating the valid period of the vertical synchronization signal from the character line counter. A display screen movement control device comprising: means for enabling display; and a display screen movement control device.