JPS6333782A - Controller for graphic display - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control device for a graphic display of a laser diagonal type that displays characters, figures, etc. on a display screen;
In particular, it relates to the character drawing method.

[Conventional technology]

FIG. 2 is a diagram showing the configuration of the font control section of a conventional graphic display device. In the figure, (1) is the main control section, (2) is the font address counter, (
3) is a font address register, (4) is a font ROM in which font data is stored, (5) is a selector that selects one predetermined bit from the several bits read from the font ROM (4), (6) is an expanded dot, (7) is an AND of expanded dot (6) and font information.
AND @ path, (8) is the screen memory/X side address,
(9) is the screen memory/X side address; (10) is the screen memory/address control unit that generates a physical address in one-to-one correspondence from the X-side address (8) and the X-side address (9); (N ) is screen memory.

Next, the details of the operation will be explained. For convenience of explanation, the case where the font has a 16×16 dot configuration will be explained as an example. The main control unit (1) outputs the start address where the font data of the character to be drawn is stored to the font/ROM (4), and at the same time instructs dot expansion by setting the expansion dot (6) to 1". The font address register (3) consists of, for example, 8 bits, and the upper 4
Bits are given to the font ROM (4), and from this E 16-bit font data is sent to the selector (5).
) data input. The lower 4 bits of the font address register (6) serve as a select signal for the selector (5), and 1 bit of font data is selected from 16 bits. This is then ANDed with the expanded dot (6) in the IJD circuit (7), and this is the screen memo! This becomes the data to be written to J(11). On the other hand, in the font address counter (2), the font address output from the font address register (3) and 1" of the expansion dot (6) are added, and when the next dot expansion is instructed, Font address register (
3).

That is, the initial value of the address counter (2) is 0''. This is reset for each character. Expanded dots (6) are output one dot at a time. The first 16 bits are the font The upper 4 bits of the address register (3) are ``0000''. The lower 4 bits of the font address register (3) control which dot out of these 16 dots (one line) is selected. Further, only the start address of the character to be drawn is output from the main control unit (1) to the font ROM (4).

These matters are illustrated in FIGS. 6 to 5. In FIG. 3, (&) is the start address, and the address in the vertical direction, that is, the row direction, is determined by the upper 4 bits of the font address register (3). The 16-bit font data (4a) thus determined is sent to the selector (5) as the output of the font ROM (4). In the selector (5), one bit out of 16 bits (for one line) is determined by the lower four bits of the font address register (3).
Here, for example, the address "0110" is selected.The AND circuit (7) then ANDs this and the expanded dot (6), and this is the data to be written to the screen memory (11). FIG. 4 is a timing chart showing an example of these operations.

The rising edge of the output pulse of the expanded dot (6) is the timing for setting the font address register (3), and the falling edge is the timing for setting the font address register (2).
It's time for the count up. and,
Although the two pulses output from the AND circuit (7) have shortened the time axis shown below, they resonate at the 3rd and 4th bits of the 4 bits that correspond to 13". shows an example of 16-dot character font data.

Return to Figure 2 and take a note of the screen! The screen memory address when writing screen memory write data to J (11) is determined by the main control unit (1) every time one dot is developed.
X-side address (8) and screen memory/X-side address (9)
is output, and the screen memory address control unit (10) generates a physical address of the screen memory. Based on this address, a predetermined dot is written in the screen memory (11).

[Problem that the invention seeks to solve]

Since the conventional display control device is configured as described above, the main control section must generate a screen memory address for each dot development, and in order to write one character, it must be executed 16 x 16 times. Since it is necessary to generate an address, there are problems such as a heavy load on the main control section, slow processing, and making circuits after the main control section wait.

This invention was made to solve the above-mentioned problems, and aims to provide a control device with increased processing speed by reducing the load on the main control unit to generate screen memory addresses. do.

[Means for solving problems]

The graphic display control device according to the present invention has a screen memory for controlling the X-side address of the screen memory and the X-side address, which is dedicated to drawing characters on a conventional display.
It has an additional address control circuit.

[Effect]

The X-side address and X-side address of the screen memory are output only once for each character, and the X-side address and・Generated by the address control circuit.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, parts (1) to (11) are the same as or correspond to the conventional control device shown in FIG.

(+00) is the added screen memory address control circuit, ('2) is the first X side address selector of the screen memory, (ta) is the 1" addition circuit, (14) is the 16" subtraction circuit, (15) is the second X-side address selector of the screen memory, (16) is the first X-side address selector of the screen memory, (17) is the "1" addition circuit, and (18) is the second X-side address selector of the screen memory. The X-side address selector, (19) is the X-side address register, and (20) is the X-side address register.

Next, the operation will be explained. Similar to the conventional control device shown in Figures 2 to 5, the main control unit (1) outputs the start address where the font data of the character to be drawn is stored to the font ROM (4). At the same time, dot expansion is instructed by setting the expansion dot (6) to ``1''.The font address register (3) consists of 8 bits, and the upper 4 bits are used for the font ROM.
(4), and the 16-bit font data becomes data input to selector (5). Additionally, the lower 4 bits of the font address register (6) serve as a select signal for the selector (5), which selects 1 out of 16 bits.
Bit font data is selected. And AN
This is ANDed with the developed dot (6) in the D circuit (7), and this becomes the data to be written in the screen memory (11). On the other hand, in the font address counter (2), the font address output from the font address register (3) and II, II of the expansion dot (6) are added, and when the next dot expansion is instructed, Set in font address register (6).

The screen memory address when writing screen memory write data to the screen memo IJ (11) is determined from the main control unit (1) once when the first dot of one character is expanded.
side address (8), screen memory/X side address (9) are output, and at this time the first X side address selector (12)
, and a first X-side address selector (16), the X-side address (8) and the X-side address (9) select the input terminal B side, respectively. The input terminal B side is selected by the first Xll1 right side X side address selectors (12) and (16) only when drawing the first dot, and normally the input terminal A side is selected. The X side edict and X side addresses (8) and (9) selected by the first X side and Y@ address selectors (12) and (16) are stored in the screen memory by the screen memory address control unit (10). Generate a physical address and omit the first dot data. Regarding the drawing after the second dot, the data written to the screen memory is the same as above. On the other hand, to generate the screen memory write address, the second dot has the screen memory X@address (8) stored in the X side address register (19) in advance.
These outputs become data inputs A and B of the second X-side address selector (15) through the "1" addition circuit (16) and the "16" subtraction circuit (14), respectively. In addition, the X-side address (9) is stored in advance in the X-side address register (20), and this output directly becomes the data input of the second X-side address selector (18). Through (17), it becomes data human power B. Second X
side and X side address selectors (15), (113:)
is 16 in font address counter (2)
Control is such that the input terminal B side is selected each time it is counted, and the input terminal A side is normally selected. Therefore, since the A side of the input terminal is selected at the second dot, "1" is added to the X side address (8), and the X side address (9) is sent to the first X side address selector with the same value. (12), the screen memory address control unit (1) via the first X side address selector (16).
0) is input. Then, the physical address of the screen memory for the second dot is generated, and the second dot is written to the screen memory (N). Up to 16 dots are drawn by adding "+, n" to the X side address as described above. When the 16 dot drawing is completed, the second X side and X side address selectors (1S) and (1a) are input. Select the B side of the terminal. Therefore, the X side address (8) of the 17th dot is 1.
It will be the same as the dot, and the X side address (9) will be "
1" is added.

From then on, up to the 62nd dot, the X-side address (8) is again incremented by 1 for each dot, and the X-side address (9) is held. From the 33rd dot onward, the screen address generation operation from the 17th dot to the 32nd dot is repeated 14 times, and all screen memory write data for one 16x16 dot character is written into the screen memory (11).

When one character's worth of data is written, the start address of the next character or figure is determined by directly sending the X side address (8) and X side address (9) from the main control unit (1).
The first X-side address selector (12) and the first X-side address selector (16) are controlled to select the B side of the input terminal.

In the above embodiment, a 16x16 dot font is used, but the number of dots in the font is not limited to this, and any number of dots may be used.

In addition, although we have shown the case where one dot at a time is written to the screen memory, this is possible by reading out several dots at a time from the font/ROM and changing the number of expanded dots and address count in units of several dots to write data in multiple dots. It is possible to do this, and the same effects as in the above embodiment can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, instead of controlling the X-side address of the screen memory and the X-side address by the main control unit, a dedicated screen memory address control circuit is added and the X-side address is controlled by this Since the main control unit is configured to
The side address is generated only once at the beginning of each character, so the load on the main control unit is reduced, and this has the effect of increasing the processing speed of font drawing.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a font control section of a graphic display according to an embodiment of the present invention, FIG. 2 is a block diagram showing a font control section of a conventional graphic display, and FIGS. FIG. 2 is a common operation explanatory diagram for explaining the operation of the control section in FIGS. 1 and 2; In the figure, (1) is the main 11tlJ controller, (2) is the font address counter, (3) is the font address register, (4) is the font ROM, (5) is the selector, and (6) is the Expanded dot, (7) is an AND circuit,
(8) is the screen memory/X side address, (9) is the screen memory/X side address, (10) is the screen memory/address control section, (11) is the screen memory, (12) is the first X side address Selector, (15) is "1" addition circuit, (14)
is ""16' subtraction circuit, (15) is the second X-side address selector, (16)? [X side address selector of 1, (
17) is the 11″ addition circuit, (18) is the second X-side address selector, (19) is the X-side address register, and (20) is the second X-side address selector.
) is the X side address register. In addition, the same reference numerals in the diagram indicate the same or equivalent parts.
Soga Michi Teru, Nopa (: ・18r) Ngō 1 diagram

Claims (1)

[Claims] This is a control device for a graphic display that displays characters, figures, etc. on a display screen, and is connected between the main control unit and the screen memory, and an address is added by 1 for each dot of each displayed character. , an X-side address control unit that generates an X-side address that returns and repeats this when the number of dots for one line of one character is reached, and a Y-side address that is incremented by 1 for each line of one display character. A screen memory/address control circuit dedicated to character drawing is provided, consisting of a Y-side address control section that generates an address, and the main control section controls the X-side address control section and the Y-side address control section to A graphic display control device characterized by supplying an address signal only when dots are developed.