JPS58123582A - Cursor generator - 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 The present invention relates to a cursor generating device for generating a cursor display on a display surface of a computer system.

The generation and control of cursor display on the display surface of a computer system is normally performed using a cursor control function of an image control device (hereinafter abbreviated as CRTC) having a built-in cursor output circuit.

FIG. 1 is a block diagram showing an example of a conventional cursor generation device including an image control device. In the same figure, 1 is a central performance processing unit (hereinafter abbreviated as CPU), 2 is a CRTC, and 3
is a multiplexer, 4 is a display storage device, 5 is a data parallel-to-serial converter, 6 is a video signal control device, 7 is a display, 8 is an address bus, 9 is a data bus, 10
11 is the memory address line from the CRT C that indicates the position of the displayed character on the screen (refresh memory address line for refreshing the dynamic RAM as the display storage device 4), and 11 is the line number in one line. raster address line from CRT C, 12
is the display timing signal line, 13 is the cursor display Shingetsu line,
14 is a horizontal synchronizing signal line, 15 is a vertical synchronizing signal line, 16 is a character clock signal line representing a character unit, 17 is a display data signal line, and 18 is a video signal line.

As is well known, CILTC2 (for example, Hitachi IC)
The ID46505S) has internal registers for setting the cursor display position, cursor shape, cursor link (blinking of the cursor) and its cycle, etc. These allow you to easily control the cursor on the display surface with the circuit configuration shown in Figure 1. generation can be controlled. Note that the cursor generation control referred to here refers to displaying various cursors such as underline cursors and block cursors on the screen consisting of the display surface, and making the cursor display blink. .

Now, from CRTC2, refresh memory address 1
Since 0 and raster address 11 are output, a certain correspondence is made between these addresses and address 8 from the CPUI, and the desired display data is thereby retrieved from the display storage device 4.

Here, address 10.11 from CRTC2 and CPU
Considering the correspondence with address 8 from I, there are various possible correspondences, one of which is CPU
It is assumed that the raster address 11 corresponds to the lower order of address 8 from I, and the refresh memory address 10 corresponds to the remaining part of address 8. raster address 1
1 specifies the maximum number of rasters set in advance (usually the number of rasters for one line) and then repeats the same address specification as 1 cycle. If you set 4&, the 2-bit raster address will be (o,
oL(o+tL(1toL(1t1)), followed by the same < (otoL(o+1)t(1tO)!(11
Repeat 1) continuously. Therefore, if these raster addresses are made to correspond to the lower two bits of address 8 from CP TJ 1, the addresses given to the display memory device [4 will be continuous.

In other words, when the maximum number of rasters is 2n (where n is a natural number), the memory addresses corresponding to the screen are continuous, but if this maximum number of rasters is not a number corresponding to 2r', the display storage Ato L who can live to 4/
″%A, discontinuous numbers become 0.9. For example, when the maximum number of rasters is 3 (~2″), the raster address is (O
tO) + (Otl)t('tO), and then (
] +1) and returns to (010), resulting in discontinuity. Also, the cursor shape is determined by specifying the number of rasters within this maximum number of rasters, so 1
In order to output a block cursor for characters by CI''LTC2, it is necessary to make the number of rasters for one line the maximum number of rasters.

Therefore, with the method of directly using the cursor display signal 13 from the CRTC 2 as shown in Figure 1, there is no problem when the character structure on the screen is 8 x 2n dots/character (n is a natural number), but the character structure is If it is not 8x2'' dots/character, for example 8x12 dots/character, an inconvenience will occur.This point will be described below.

First, if the character structure is 8 x 21 dots/character,
Considering the case of 8×8 dots/character and 80 characters/line, CI
If the setting values of t and T C2 are the number of horizontally displayed characters 80, the number of rasters for one line 8, and the start address O, then the address of the display storage device 4 corresponding to the screen is G as shown in Figure 2.
This will happen. In this case, the addresses in hexadecimal display are continuous over the entire screen, and the minimum display storage device (no unused addresses in the storage device, that is, the minimum storage window f without waste) is sufficient. Top, CRT C
The second function allows you to freely control the shape of the cursor and the links.

Next, consider the case where the character structure is 8 x 12 dots/character and 80 characters/line, and change the setting value of CTLTC2 to 8 horizontally displayed characters.
Assuming that the number of rasters for 0.1 line is 12 and the start address is O, the memory address corresponding to the screen is as shown in FIG. In this case, of course, the cursor shape and link can be freely set using the functions of C1l and Te3, but as is clear from Figure 3, the addresses in hexadecimal display are discontinuous every 12. , the remaining unused addresses 13 to 16 are generated in the display storage device, which creates an unnecessary memory area, which is not practical. For example, if the character structure is 8 x 12 dots/character and the number of displayed characters is 80 characters x 20 lines, the memory capacity would normally be 19.2 bytes, but due to the generation of unused addresses, it would be 25. This is not practical because it requires a capacity of 6.6 bytes, of which 6.4 bytes are unused.

Therefore, in order to eliminate this address discontinuity,
Considering that the setting value of RTC2 is that the number of horizontal display characters is 80. The number of rasters for one line is 4, the start address is 0, and the character structure of 8 x 12 dots is apparently composed of (8 x 4) x 3 dots. The addresses of the display storage device 4 are as shown in FIG. 4, and it is true that the addresses are continuous over the entire screen. However, one character (
Since it is composed of 8x4)x3 dots, if you try to output a block cursor, the cursor will only appear in a block of 1/3 of one character. I can't.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to make it possible to freely output a 7'o-tsk cursor for one character without discontinuing the addresses of the display storage device corresponding to the screen. An object of the present invention is to provide a cursor generator.

The gist of the present invention is to provide a cursor generation device capable of outputting a cursor display of at least one line on the screen, using a cursor signal for displaying the cursor as a reference, for any N horizontal scanning period thereafter (however, N is a natural number), and is provided with a cursor signal output circuit that outputs a cursor signal every horizontal scanning period, making it possible to display a cursor on any number of lines.

The present invention will now be described in detail with reference to the drawings.

FIG. 5 is a block diagram showing one embodiment of the present invention. In this figure, the same parts as in FIG. 1 are given the same reference numerals, and numerals 21 to 26 indicate the constituent elements of the embodiment of the present invention. That is, 21 includes a counter that measures one horizontal scanning period (hereinafter abbreviated as IH), and the IH
a cursor display circuit that generates a cursor signal for each
1 is a counter that controls the number of lines that make up the block cursor; 23 is a gate circuit that synthesizes and outputs the cursor display signal from C11T C2 and the block cursor signal from the cursor display circuit 21; and 24 is a block cursor. 25 is a block cursor signal, and 26 is a composite block cursor signal.

FIG. 6 is a timing chart of various signals in the circuit of FIG. 5. In FIG. 6, (a) is the character clock signal 16 in FIG. 5, and Φ) is the horizontal synchronization signal 1.
4, (C) shows the cursor display signal 13, (d) shows the block cursor signal 25, and (e) shows the combined block cursor signal 26, respectively.

Now, based on Figure 5 and Figure 6, the character structure is 8 x 12.
The case where a block cursor is output when it is a dot/character will be explained.

First, regarding the CRTC2 settings in this case, as already mentioned, if the maximum number of rasters is set to 12, the memory addresses corresponding to the screen will be discontinuous because this is not a number equivalent to 2n. So, for example, as shown in Figure 4, 8x12 dots/characters are (8x4)x3
Considering it as a dot/character, the maximum number of rasters is 4 or 2rl.
Set it to a number that can be expressed as , so that the memory addresses corresponding to the screen are continuous, and from CR'l' C2, only the topmost line of the desired block cursor appears on the cursor display signal line 13. Set it as follows.

The cursor display signal 13 and character clock signal 16 are then input to the cursor display circuit 21. The counter included in this cursor display circuit 21 is set in advance with the number of character clocks for I1.
After the cursor display signal 13 (FIG. 6C) is input, the character clock signal 16 shown in FIG. A signal (block cursor signal 25) as shown in Figure (d) is output. and,
This block cursor signal 25 and the cursor display signal 13 of only one line (FIG. 6C) are synthesized by the gate circuit 23, and the synthesized block cursor signal 26 shown in FIG. 6(e) is
That is to say.

At this time, the number of block cursor signals 25 is subtracted by 1 from the number of lines forming the block cursor.

The line number designation signal 24 (in the case of 12 lines per block, this value is 11 because it is subtracted by 1)
When the number of cursor signals 25 reaches the set value, the gate circuit 13 is controlled and closed by the output of the counter 22, which generates a block cursor of a desired size. can be displayed. Furthermore, it goes without saying that by changing the set value of the counter 22 using the line number designation signal 24, a block cursor with an arbitrary number of lines can be output.

In the embodiment shown in FIG. 5, the character clock signal 16 is used as a unit signal for measuring IH, but it is not necessarily necessary to use this signal. May be used. Furthermore, in order to output a cursor signal for each IH based on the cursor display signal 13, instead of using the cursor display circuit 21 including a counter as in the embodiment shown in FIG. An IH delay element or the like may also be used. The point is that it is sufficient to output the next signal every 1H for one basic signal.

Next, instead of the cursor display circuit 21 in FIG.
An embodiment using a delay element is shown in FIG.

In FIG. 7, the same parts Q as in FIG. 5 are given the same numbers, and 27 is a gate circuit,
is an I I-1 delay element.

To explain the operation, in the embodiment O shown in FIG.
The settings of TC2 are the same as in Figure 5, and only the topmost line of the block cursor is the cursor display signal line 1.
Appears in 3. This signal is passed through the gate circuit 27 to I
The signal is input to the H delay element 28.

Then, after 1)I, this signal is output and is inputted to the IH delay element 28 again via the gate circuit 27. By repeating this, the cursor display signal 1
Block cursor signal 25 one after another for each IH for 3
is output. The counter 22 counts the number of Kutzl signals 25 to obtain a block cursor of a desired size, as in the embodiment shown in FIG.

According to the present invention, the character structure is 8X2 (n is a natural number)
Even with dots/characters, the desired block cursor can be output on the display surface without making the memory addresses corresponding to the screen discontinuous, and the memory capacity of the display storage device can be minimized. There is an advantage.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a conventional cursor generation device including an image control device, and Fig. 2 is an explanation showing the memory addresses corresponding to the screen when the maximum number of rasters is 8 and the number of horizontally displayed characters is 80. In Figure 3, the maximum number of rasters is 12,
An explanatory diagram showing the memory addresses corresponding to the screen when the number of horizontally displayed characters is 80. Figure 4 shows the maximum number of rasters: 4,
An explanatory diagram showing the memory addresses corresponding to the screen when the number of horizontally displayed characters is 80, FIG. 5 is a block diagram showing one embodiment of the present invention, and FIG. 6 is a timing diagram showing the signal relationship of each part in FIG. 5. , FIG. 7 is a block diagram showing another embodiment of the present invention. Code explanation 1...CPU, 2...Song image control device, 6...
Song video signal control device, 13...Cursor display signal line, 14...Horizontal synchronization signal line, 15...
... Vertical synchronization signal line, 16 ... Character clock signal line, 17 ... Display data signal line, 1
8... Video signal line, 21... Cursor display circuit, 22... Line number control counter,
23...Gate circuit, 24...Line number designation signal, 25 River...Block cursor signal, 26
......Synthetic block cursor signal, 27...Song gate circuit, 28...1) 1 delay element agent
Patent Attorney Akio Nami Ki Figure 1 f Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1) In a cursor generation device capable of outputting a cursor display consisting of at least one line on the screen, an arbitrary N horizontal scanning period (N is a natural number) after the cursor signal for the cursor display is used as a reference. A cursor generator fL is characterized in that it is equipped with a cursor signal output circuit that outputs a cursor signal every horizontal scanning period, and is capable of displaying a cursor of any number of lines.