JPS62161191A - Crt controller - 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 [Field of Application of the Invention] The present invention relates to a CRT (cathode ray tube) controller for a CRT (cathode ray tube) display.

[Background of the invention]

With the diversification of display system configurations, the recent use of kernel displays has shifted from the traditional use of characters to indicate a certain area on the display screen. However, conventional CR
In the cursor No. 11 output from the T controller, for example, the drawing LS1. HD63484/ACRTC User's Manual (Hitachi June 1980 680-1
-28) As shown in Pb0, the width of the cursor is set in the range of 1 to 8 characters according to the memory address corresponding to the character, so it is suitable for indicating characters and phrases on the display screen. However, since it cannot indicate arbitrary areas in the horizontal direction, the cursor could not be used for purposes other than conventional cursors, such as for creating ruled lines, underlining, and dividing the screen.

[Purpose of the invention]

An object of the present invention is to provide a CRT controller with a half-recessed cursor display that can set a cursor signal corresponding to a memory address to an arbitrary width in the horizontal direction on the display.

[Summary of the invention]

The present invention provides a means for outputting a cursor signal in response to the output of a memory address for display memory according to settings from outside the CRT controller, and a means for outputting a cursor signal at an arbitrary position up to a maximum of one horizontal line in the horizontal direction of the display screen. By using and, the cursor is output horizontally with an arbitrary width, and a border is created.

This allows it to be used for purposes such as underlining and dividing the screen.

[Embodiments of the invention]

FIG. 1 is a configuration diagram showing a single flag array according to the present invention, and FIG. 2 is a timing diagram showing its operation.

The cursor display position register 1 is an externally writable register that sets the position at which the cursor starts outputting in correspondence with the display memory address. Reference numeral 2 denotes a memory address counter, which is incremented every character time by an external character clock 14, and generates a display memory address. 3 is a flip-flop tab, the output of which becomes a cursor width signal 4. 5
is a cursor width register that sets the width of the cursor, and is an externally writable register that can be set to at least the total number of horizontal characters in order to output the dust cursor width with a maximum width of one horizontal line. 6 is a cursor width counter for counting the width of the cursor, and is capable of counting at least the total number of horizontal characters.

Generation of the cursor width signal will be explained below with reference to FIGS. 1 and 2.

It is assumed that the cursor display position register 1 is set in advance as the cursor display position 7 at which cursor output starts, and the contents of the display memory address corresponding thereto.

The memory address counter 2 is incremented every character time by a character clock 14 which is externally applied to the CRT controller and has a period of one character time.
When the display memory address 8 output from the memory address counter matches the cursor display position 7, the comparator 9
Set 1 to set flip-flop 3 by
Outputs word 10. When the cursor width signal 10 is input to the flip-flop 3, the cursor width signal 4 is output. On the other hand, the reset signal 11 of the cursor width counter 6 is set to change from high to low at the same time that the flip-flop 3 is turned on.
As a result, the cursor width counter 6 is reset,
Incrementing is started for each character time based on the input character clock 14.

When the output 12 of the cursor width counter 6 matches the cursor width 13 set in advance in the cursor width register 5, the comparator 15 outputs a reset signal 16 for resetting the flip-flop 3, and the cursor width signal 4
Terminate the output of .

At the same time, the reset signal 11 of the cursor width counter 6
This reset signal 11 puts the cursor width counter 6 into a reset state and waits for the next cursor output.

FIG. 2 is a timing chart when a counter that increments at the rising edge of the character clock 14 is used, an RS flip-flop is used as the flip 70 block 3, and the cursor width is set to 4.

According to the embodiment shown in FIG. 1, as shown in FIG. 3, depending on the setting of the cursor width register 5, the cursor can be moved to a width of several characters like 18, or the cursor can be moved to a horizontal display width like 19. It is possible to output it and use it as a ruled line.

The present invention is not limited to the above embodiments.

For example, the flip-flop 70 may be any type of flip-flop that maintains its output state in order to output a cursor width signal; it is not limited to a flip-flop. In addition, 7th 21 flop 5 reset) (H16 is the cursor width register 5 and cursor width counter 2 in the above disaster example)
We use the signal that is output when the outputs of
Instead of this No. 16, use another hli control No. 16 used inside the CRT controller for 1 horizontal quantitative time circle.
It is also possible to combine several of these signals to use ~・℃(・.

For example, as shown in FIG. 4, a four-rule type decoy flip-flop is used as the flip-flop 5 shown in FIG. 1, a character clock 14 is used as a synchronization signal, and the flip-flop is reset by inputting a reset signal 16. 4B to clear the clip flock. Horizontal run fP as %: C output at the end.
A method may be adopted in which the internal signal 20 of the RT controller is used to clear the clipflock. The internal key is generated, for example, by a comparison signal that is output when the values of the character counter inside the CRT controller and the horizontal total number of characters register match.

In this method, after the input levels of the set signal 10 and the reset signal 160 of the flip-flop 3 are depleted, the reset mfT= of the flip-flop 30 is performed in synchronization with the character clock 14, so that the set color code, Even if a hazard occurs in the reset signal, it is effective to prevent malfunctions.

In addition, 1J No. 20 is output at the end of horizontal scanning.
This clears the fritsuno flop 3, so even if you set a value in the cursor width register 5 that would cause the cursor to be displayed beyond the display width, the cursor will end at the end of the line and will not be displayed next time. p is not shown on the line. Therefore, when using the cursor for purposes such as line confusion, set the value of cursor width register 5 to a value greater than or equal to the display width.
614 is ℃・. In addition, if the screen is divided into two or more vertically, the cursor is output only within one line, so the cursor will not be displayed across two screens, and the cursor width register This has the effect of not imposing any specific restrictions on the settings of 5.

In addition, instead of ★, a horizontal synchronization signal is generated by a comparison signal that is output when the values of the character counter inside the CRT controller and the horizontal total number of characters register match.
Even if No. 11SYNC is used, the same effect as 1r-1 can be obtained. Also, instead of l-IMAX, H8YNC, C
4g No. 1 (DMAX) which specifies the end of the horizontal display period generated by the comparison key signal output when the values of the character counter inside the RT controller and the horizontal display character number register match. May be used.HDM
When AX is used as a clear key for a flip-flop, the cursor is only valid within one line of display axis, so if you change the display range on the screen, such as changing the window size, Even in this case, since the cursor is not output beyond the display range, it has the effect that the cursor can be made effective within the range of the window, etc., by using the display range of the four devices that constitute the window.

〔Effect of the invention〕

As explained above using the embodiments, according to the present invention,
Since the cursor signal can be set to any width in the horizontal direction, the cursor signal is not limited to the conventional use of cursors, but can be applied to a wider range of functions (such as ruled lines and underlines). .

[Brief explanation of drawings]

Fig. 1 shows an embodiment of this invention, and Fig.
5 is a timing diagram for explaining the present invention, FIG. 5 is a reading diagram showing an example of t+ at V on the cursor stroke (3) according to the present invention, and FIG. FIG. 2 is a circuit diagram showing a specific example. 1... Cursor red water position register, 2... Memory address counter, 3... Flip 70 knob, 4... Cursor width 1g, 5... Cursor I fall register, 6... Cursor width counter /ri, 7...Cursor display position, 8...Display memory address, 9...Comparator, 1o...Set signal, 1
1... Reset signal, 12... Cursor width counter output, 13... Cursor width, 14... Character counter, 15... Comparator, 16... Reset signal, 17...
Display screen, 18 river cursor, 19... cursor,
20...HMAX.

Claims (1)

[Claims] 1. In a CRT controller for a CRT (cathode ray tube) display, means for generating and outputting a display memory address by counting a character clock input from the outside, and setting a cursor display position. cursor display position holding means for setting the cursor width within the range of the total number of characters up to one horizontal line on the display and outputting the cursor width signal; A cursor width counter that counts input character clocks and outputs the result compares the display memory address from the display memory address generation means and the cursor display position signal from the cursor display position holding means, and calculates both. The count result output from the cursor width counter and the cursor width signal from the cursor width holding means are compared, and when they match, it is reset, and the cursor width is At the same time as the output of the cursor width signal from the signal output means and the cursor width signal output means is started, the reset state of the cursor width counter is released and character clock counting is started, and the cursor width signal is output. means for resetting the cursor width counter at the same time as the end of character clock counting; and cursor display means capable of displaying a cursor of any length within one line in the horizontal direction on the display. A CRT controller characterized by: 2. The CRT controller according to claim 1, wherein the cursor width signal output means is configured to be reset also by an internal signal output at the end of horizontal scanning. CRT controller.