JPH01293389A - Cursor data control circuit - Google Patents

Abstract

PURPOSE:To enable cursor movement by simple software by providing a cursor data storage means, a display address generating means, a cursor position storage means, and a cursor size storage means. CONSTITUTION:A read means 500 which reads cursor data out reads cursor data out of the cursor size storage means 300 in response to a coincidence pulse from an address coincidence detecting means 400 and generates addresses corresponding to the size data. Then cursor data is read out of the cursor data storage means 20 and while this cursor data is read out, the cursor data is supplied to a display device instead of the output of an image memory. For the purpose, respective data are written in the cursor data storage means 20, cursor position storage means 200, and cursor size storage means 300 to enable the cursor movement automatically and also reduce the processing load by the software greatly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a cursor data control circuit used in display devices such as personal computers and word processors.

(Prior Art) When data is input to a display device of a personal computer, a word processor, etc., a graphic character, etc. corresponding to the input data is displayed on a display device using a cathode ray tube or a light emitting element. At this time, it is common to display a cursor as well to clearly indicate the position of the input data.

Furthermore, when correcting input data, a cursor is displayed at the corrected location to clearly indicate the corrected position. This cursor is used for cathode ray tubes (CRTs) and light emitting devices (L).
The generation timing of the cursor is controlled by the cursor data control means so that the cursor can be freely moved within the effective display area of the display device using the cursor ED. Normally, the displayed cursor is displayed in a size that matches the size of the character, etc. at that position. The size of letters, etc. is lower case.

There are standards such as medium-sized characters, standard characters, double-width characters, double-height characters, and double-height and double-width characters. Therefore, the size of the cursor is also selected in accordance with the size of the characters, etc.

As mentioned above, there are various cursor sizes, and it is necessary to appropriately select and display the cursor. Next, a control method for displaying a cursor will be explained.

For example, the case where the cursor is moved one character to the right on the display area will be explained as follows.

(2) In the image memory having an address corresponding to the display area, data (characters, etc.) at the destination (address) to which the cursor is to be moved is first temporarily saved to the work RAM.

■Next, cursor pattern data (cursor data)
is written to the destination address of this image memory. ■Then, data such as characters that should originally exist here is stored in the working RAM at the address that existed before the cursor data moved.
Read from and fill in the blanks.

The above processing is usually performed by a control means such as a microprocessor through software processing.

According to such cursor control, data saving and restoring processing is performed by software every time a cursor movement command is input, so that the software processing of the microprocessor is complicated. Also, the size of the cursor is
It must be managed according to the character size, and the software itself for writing and saving data becomes complicated.

Furthermore, if it becomes necessary to perform other processing in parallel while the cursor is moving, a problem may arise in that the processing speed, that is, the moving speed of the cursor becomes slow.

(Problems to be Solved by the Invention) According to the conventional cursor control means, the saving and restoring of data in the 9-image memory, the generation and movement of the cursor, etc. are all performed by software, which makes the software complex. Furthermore, when it becomes necessary to perform other processing in parallel, there is a problem in that the moving speed of the cursor becomes slow.

Therefore, an object of the present invention is to provide a cursor data control circuit that can realize cursor movement with simple software.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a cursor data storage means that can write cursor data of any display size, and a display that generates an address corresponding to a display area of a display device. address generation means; cursor position storage means in which an initial address for displaying the cursor within the display area is written; and size data indicating the size of the cursor written in the cursor data storage means. and address coincidence detection means for comparing the display address generated by the display address generation means and the initial address of the cursor position storage means and outputting a coincidence pulse when the two addresses match. do. A reading means for reading cursor data takes in the size data stored in the cursor size storage means in response to a coincidence pulse from the address coincidence detection means, generates an address for this size data, and generates an address corresponding to the size data. The cursor data stored in the storage means is read out, and while the cursor data is being read out, the cursor data is supplied to the display device instead of being output from the one-picture-one-image memory. It is.

(Function) With the above means, there is no need to perform processing such as saving and restoring data in the image memory as in the past, and each data is stored in the cursor data storage means, cursor position storage means, and cursor size storage means in advance. If you write, the cursor can be moved automatically, greatly reducing the processing burden on the software. Even if the cursor size is different, this process only increases the number of write clocks to the cursor data storage means, and saves data as usual.
In each process of writing cursor data and restoring data, the processing time does not differ depending on the size.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, and FIG. 2 is a diagram shown for explaining an example of cursor size. The cursor size is small font size (height 12 bits, width 8 bits).
character size (48 bits high, 32 bits wide)
bit (4 bytes)]. Therefore, as a RAM that can store cursor data of any display size,
4×48−192)<items are required, and if it is configured by a register group, 192 8-bit registers are required. Figure 2 shows data storage when a cursor with a crosshair-shaped main body is displayed in small character size (Figure 2 (a)) and when it is displayed in double height and width character size (Figure 2 (b)). 3 shows an example of data location in the means.

The cursor data storage section 20 shown in FIG. 1 can store cursor data of any size as described above. The cursor data is processed by a microprocessor (hereinafter referred to as C).
PU) is supplied to the cursor data storage section 20 via the data bus DB and the three-state buffer circuit 19. The write address at this time is given to the cursor data storage section 20 from the CPU via the address bus AB and the switch section 18. When writing cursor data, the switch signal SWI from the CPU becomes, for example, a high level, and the switch section 18 is connected to the address bus A.
B side is selected, and the three-state buffer circuit 19 transfers the input data from the data bus DB to the cursor data storage section 2.
It is switched to lead to 0.

Furthermore, the CPU also performs the processing described below.

(2) The CPU can set the initial address of the display area to the display address generation section 100 via the data bus DB. The display address generation unit 100 has an X address counter 1 and a Y address counter 2, and sequentially generates addresses for the entire effective display area of the display device.
X address counter 1 is driven by byte clock BCK, and Y address counter 2 is driven by line clock L.
Driven by CK. This display address generation section 1
The output address 00 is originally used as a read address of an image memory (not shown).

In a video text system, for example, the X direction address is 0 to 30 and the clock BCK is a pulse of 8 bits, and the Y direction address is 0 to 203 and the clock LCK is
is a pulse of one horizontal period.

(2) The CPU can set an initial address, which is the display start position of the cursor to be displayed, in the cursor position storage unit 200 via the data bus DB. The cursor position storage unit 200 has cursor position registers 3 and 4 that store addresses in the X direction and addresses in the Y direction.

(2) The CPU can store size data of a value corresponding to the size of the cursor to be displayed in the cursor size storage section 300 via the data bus DB. The cursor size storage unit 300 has cursor size registers 5 and 6 that store data about the size of the cursor in the X direction and the size in the Y direction.

(2) The CPU can store flag data for determining whether or not to display a cursor in the flag register 7. If the cursor is to be displayed, a flag of "0#" is stored if the m 1 s1 line is not displayed.

The match detection unit 400 compares the address generated by the display address generation unit 100 and the address stored in the cursor position storage unit 200 (indicating the display start position of the cursor), and when the two addresses match, outputs a load pulse. LX
and LY are output. The coincidence detection unit 400 includes a coincidence detection circuit 8 that detects a coincidence or mismatch of addresses in the X direction, and a coincidence detection circuit 9 that detects a coincidence or mismatch of addresses in the Y direction.
and has.

Load pulses LX and LY are read address generator 5
00 down counters 10 and 11, respectively. The read address generation section 500 generates a read address for the cursor data stored in the cursor data storage section 20 when the cursor starts displaying, and outputs the read address according to the size of the cursor.

That is, when load pulses LX and LY are applied, down counters 10 and 11 take in values indicating the cursor size from size registers 5 and 6 (preset), respectively. Normally, the values of the down counters 10 and 11 are all "0", and in this case, "0" determination circuits 14 and 15 provided corresponding to each counter detect this fact. The contents of down counters 10 and 11 are all “0”
At this time, the outputs of the "0" determination circuits 14, 15 are at a low level, and the AND circuits 12, 13 are non-conductive, so that the driving clock is not supplied to each down counter 10, 11. However, as described above, when the size data is loaded, the "0" determination circuits 14 and 15 switch the AND circuits 12 and 13 to conductive states, so that the down counters 10 and 11 are supplied with a driving clock. Become so.

The clock supplied to the down counter 10 is a byte clock BCK in the X direction, and the clock supplied to the down counter 1
The clock supplied to No. 1 is the line clock LCK in the Y direction. The outputs of the down counters 10 and 11 are respectively supplied to address converters 16 and 17, converted into read addresses of the cursor data storage section 20, and supplied to the address input section via the switch section 18. When all the address spaces corresponding to the size of the cursor are sequentially addressed in the display area of the display device in this way, the contents of the down counters 10 and 11 become all "0", and the down counters 10 and 11 become all "0". ,1
Clock input to 1 is stopped.

Cursor data (pattern data) read from the cursor data storage register 20 is supplied to the shift register 21 via the data bus DBI. In the shift register 21, serial-to-parallel conversion of the cursor data is performed using the shift clock SFC, and the data is output in dot units and supplied to the control section of the switch section 24.

The switch section 24, the foreground (FG) color register 22, and the background (BG) color register 23 are connected to the cursor coloring section 6.
00. The cursor pattern data controls the switch section 24 in dot units, and within the cursor size area, the color data of the FG color register 22 is selected in the main body, and the color data of the 80 color register 23 is selected in the part other than the main body. It is selected and supplied to the switch section 26.

The switch section 26 selects data from the switch section 24 and supplies it to the display device during the cursor display period, and selects R, G, B, and Y data from the image memory and supplies it to the display device outside the cursor display period. supply The switch 26 is
Switching is controlled by the output of the AND circuit 25.
The AND circuit 25 determines that the output of the flag register 7 is “1”.
” and the outputs of the “0” determination circuits 14 and 15 are at a high level (data exists in the down counters 10 and 11), the output becomes a high level and the switch section 26
Controls the cursor data selection state. As coloring data for the FG color register 22 and 80 color register 23, various color data can be stored from the CPU through the data bus DB.

According to this embodiment, data for cursors of various sizes is stored in the cursor data storage means, and cursor display position data is transferred to the cursor position storage section 200 and size data is transferred to the cursor size storage section 300. A cursor display can be obtained, and there is no need for the conventional process of saving and restoring data in the image memory.

If there is no need to color the cursor, the output of the shift register 21 can be used as is. When changing the display position of the cursor, that is, moving the cursor, the cursor can be easily moved by simply changing the data in the cursor position storage section 200. Furthermore, this circuit allows the cursor pattern to be changed freely. If you want to make the cursor pattern unique to the user rather than a fixed pattern, use the cursor data storage section 20.
For example, it is easy to make changes so that data from a character generation ROM can be transferred.

[Effects of the Invention] As described above, according to the present invention, cursor display processing and cursor movement processing can be realized with simple software. In addition, because the software is simple, the processing time for cursor display and movement can be significantly reduced.
Even when the CPU performs other processing in parallel, the cursor can be moved at high speed.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram for explaining cursor size, and FIG. 3 is an explanatory diagram showing an example of cursor display. 100...Display address generation section, 200...Cursor storage section, 300...Cursor size storage section, 40
0... Match detection section, 500... Read address generation section, 20... Cursor data storage section, 21... Register, 25... AND circuit, 26... Switch section. Applicant's representative Patent attorney Takehiko Suzue No. 2 (b) Disaster double letter buoy map

Claims (1)

[Scope of Claims] A cursor data control circuit capable of displaying a cursor moved to an arbitrary position in a display area of a display device, comprising: a cursor data storage means capable of writing cursor data of an arbitrary display size; , display address generation means for generating an address corresponding to a display area of the display device; cursor position storage means for writing an initial address for displaying the cursor in the display area; and cursor data storage means. A cursor size storage means is set with size data indicating the size of the cursor written in the cursor, and a display address generated by the display address generation means is compared with an initial address of the cursor position storage means, and both addresses match. address coincidence detection means that outputs a coincidence pulse when the address coincidence detection means is supplied with the coincidence pulse from the address coincidence detection means; and means for reading out the cursor data stored in the cursor data storage means; and during a period when the cursor data is being read out from the cursor data storage means, the data supplied to the display device is stored in an image memory. 1. A cursor data control circuit comprising: switching means for switching from the output of the cursor data to cursor data.