JP2903565B2 - Character display device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a character display device, and more particularly to a character display device for enlarging and displaying a displayed character font pattern on a display.

(Prior Art) Some conventional character display devices generally use a character system or a bitmap system.

FIG. 8A is a block diagram showing a configuration of a character display device using the character system. In FIG.
1 is a central processing unit (hereinafter abbreviated as CPU) for controlling the entire apparatus, 2 is a refresh memory (hereinafter abbreviated as RM) for storing character codes, 3 is a CRT controller (hereinafter abbreviated as CRTC) for controlling CRT display, 4 is a character generator (hereinafter abbreviated as CG) that outputs a character pattern by a character code, 5 is a parallel-to-serial conversion circuit (hereinafter abbreviated as PS) that sequentially sends out a character pattern of one line of one character sentence by 1 bit, and 6 is a character. CRT to display, 7 is CRTC3 and PS
5 is an oscillation circuit that operates.

 Next, the operation will be described.

The character code written to RM2 by CPU1 is read by CRTC3 and sent to CG4. CG4 outputs a character pattern from this character code. This character pattern is converted into a 1-bit output by the PS 5 and output to the CRT 6 by the oscillator circuit 7 bit by bit. CRT6 displays this data on the display screen.

When changing the display character, the CPU 1 may access the RM 2 and rewrite the character code.

In the character display device using the character method as described above, the CRT 6 displays RM2 within the time for displaying one character sentence in one line.
The operation of CG4 and PS5 must be completed, but when using this device for a high-definition CRT6, since the display time of one dot of CRT6 is extremely short, these circuits must be operated within the display time of one character. It was difficult. Further, scrolling for enlarging a character or for viewing a non-standard area which is displayed in standard characters generated when the character is enlarged and does not enter the screen when the character is enlarged cannot be performed.

As described above, the applicant has found that the operation time of the CG is slow, so that a high-definition CRT cannot be accessed in a display time of one character.
In Japanese Patent Application No. 61-276668, a character display device having a plurality of standard and enlarged CGs and capable of scrolling display by designating a display address was proposed. FIG. 9 shows the configuration of the character display device.

In FIG. 9, the same reference numerals as those in FIG. 8 indicate the same components. In the embodiment shown in FIG. 9, two standard CGs 4-1 and 4-2 and four enlarged CGs 4-3 to 4-6 are provided for RM2.
Is used. Reference numerals 9-1 to 9-8 denote latch circuits for latching inputs at the rise of the clock from the oscillation circuit 7.
Reference numerals 10-1 to 10-3 denote multiplexers (hereinafter abbreviated as MPX) for switching input signals. Reference numeral 11 denotes a bus buffer for connecting the data bus only when the CPU 1 reads and writes RM2. 12 is a flip-flop (hereinafter abbreviated as F / F), 13 is a read-only memory (hereinafter abbreviated as ROM), and 14 is an adder (hereinafter abbreviated as ADD) for instructing an address.

Latch circuits 9-1 to 9-3 are provided between CRTC3 and PS5, and latch display ON / OFF signals of CRT6 output by CRTC3, and display control signals such as high brightness, inversion, and blinking modes. The latch circuits 9-4 to 9-8 latch data. Latch circuit 9-4 is connected between CRTC3 and MPX10-3, and latches address data from CRTC3. Latch circuits 9-5 and 9-6 are connected between RM2 and CG4-1 and 4-2, respectively, and latch even and odd addresses from RM2, respectively. Latch circuits 9-7, 9-8
Latches the character patterns from the CGs 4-1 and 4-2, respectively, and outputs them from the MPX 10-2. The latch circuits 9-1 and 9-4, the latch circuits 9-2 and the latch circuits 9-5 and 9-5
9-6, the latch circuit 9-3 and the latch circuits 9-7 to 9-8 latch the input signals at the same phase.

MPX10-1 is composed of “CRTC3 address data” + “CRTC clock inverted data” (CRTC3 side) and “CPU1 address (C
This switching is performed by the display ON / OFF signal of the CRTC3. When the signal is turned on (“1”), the signal is switched to the CRTC3 side, and when the signal is turned off, the CPU1 is switched. The MPX10-2 is connected to the latch circuits 9-7, 9 −
The character pattern data of CG4-1 and 4-2 input via the switch 8 is switched and output to the PS5. This switching becomes the output of CG4-1 when the CRTC clock is "0" and the output of CG4-2 when it is "1".

When the display on / off signal latched by the latch circuit 9-1 is off ("0"), the CPU 1
▼ When signal “0” is issued (RM2 is in write mode)
Open the buffer and RM the data (character code) from CPU1
2 Transfer.

When the display ON / OFF signal is ON ("1"), the buffer is closed, and there is no data exchange between CPU1 and RM2.

Next, the operation will be described with reference to the timing chart of FIG.

First, a character code is written into RM2 by CPU1. That is, when the display on / off signal latched by the latch circuit 9-1 is off, the CPU 1 outputs the signal "0"
Is set to the write mode via the OR gate, and the character code input from the CPU 1 via the bus buffer 11 is written to the address of the RM 2 input from the CPU 1 via the MPX 10-1.

Next, a CRTC clock as shown in FIG. CRTC3 starts operation at the rising edge of the CRTC clock, but outputs an address after a predetermined time (time required for access). The data is latched by the latch circuit 9-4 for synchronization. This latched data is sent to RM2 via MPX10-1 together with the inverted version of the CRTC clock. This CRTC
The inverted data of the clock is used as the lowest address of RM2.

For example, as shown in FIG. 11, when the address of RM2 is 0 to n in binary, the CPU 1 can write / read to / from RM2 at the address of 0 to n as it is.
To display two characters during one cycle of the TC clock,
The address of n-1 is input to MPX10-1, that is, the address of 1 to n of RM2, and inverted data of the CRTC clock, that is, "0" and "1" are applied to the address (lowest) of 0 of RM2. You are typing.

Thus, at the rising edge of the CRTC clock, an even address is input to RM2, and at the falling edge, an odd address (+1 is added to the previous address) is input.

As a result, RM2 outputs the character code of the two-character sentence in the address of one character of CRTC3 (one cycle of the CRTC clock). The even-addressed character code (a2, b2,...) Is latched by the latch circuit 9-5 at the rising edge of the CRTC clock.
1, b1...) Are latched by the latch circuit 9-6 at the falling edge of the CRTC clock. The output of the character code of the latch circuit 9-5 is output as a character pattern (A2, B2...) By the CG4-1, and is further latched by the latch circuit 9-7. Similarly, the output of the character code of the latch circuit 9-5 is CG4
Are output as a character pattern (A1, B1,...) By -2 and are latched by the latch circuit 9-8. The character pattern latched by these two latch circuits 9-7 and 9-8 is MPX
Output to 10-2. The MPX 10-2 outputs the character pattern data (A2, B2...) Of the latch circuit 9-7 to the PS5 when the CRT clock is at a high level, and outputs the character pattern data (A1, B1...) Of the latch circuit 9-8 to the PS5 when the CRT clock is at a low level. .

Thereby, the character patterns of the two CGs 4-1 and 4-2 are continuously output to the PS5. Thereby, the PS 5 can output the character pattern to the CRT 6 continuously by the clock of the oscillation circuit 7.

The display control signal of the CRT 6 output from the CRTC 3 is synchronized with the character pattern data by the latch circuits 9-1 to 9-3, so that no shift occurs. When rewriting characters, it is only necessary to rewrite the character code of RM2 by CPU1.

 Next, an operation in the case of enlarged character display will be described.

Here, the conditions of the standard character, the enlarged character, and the display character in the present embodiment are set as shown in FIG. That is, if the enlarged character is doubled vertically and horizontally, standard characters: horizontal x dot, vertical y dot (Fig. 12 (a)) Expanded characters: horizontal 2x dot, vertical 2y dot (Fig. 12 (b)) Display character ( Standard): Horizontal 2m characters, vertical 2n characters (No. 12
(Fig. (C)) Display characters (enlarged): horizontal m characters, vertical n characters (twelfth
(C) of FIG.

This condition is because all character fonts are displayed even if the character is enlarged from the standard character, and a part of the character is not lost.

When an enlarged character display signal is written from the CPU 1 to the F / F 12, the ROM 13 converts the address signal of the CRTC 3 and the raster signal under the signal control of the F / F 12.

FIGS. 13A to 13C show the address of each character when displaying standard characters, the address of CRTC, and the address of each character when displaying enlarged characters.

That is, the standard character display on the screen is 2m wide and 2n long, so the character address is 4mn from 0 to 4mn-1 (FIG. 13 (a)). Also, CRTC3 counts addresses with two horizontal characters as one character, so m horizontal characters, 2n vertical characters
It becomes a character, and the character address is 2mn of 0 to 2 nm-1 (FIG. 13 (b)).

Next is the enlarged character display on the screen (Fig. 13 (c)).
In this case, since both the vertical and horizontal directions are enlarged twice, m horizontal characters and n vertical characters are obtained. However, the address of the character is 2m-3m-1 (in the case without scrolling). In this case, since the number of rasters at the same address is doubled (standard y raster → enlarged 2y raster), raster conversion is also required. This conversion is shown in FIG.

In FIG. 14, the output address of CRTC3 is 0-2mn-1.
The output raster is 0 to y-1, but the address in the enlargement mode is 0 to m-1, 2m to 3m-1,... 2m (n-
1) to (2n-1) m-1, and the raster becomes 0 to 2y-1.

The address and raster are determined as described above, and CG4-3
4-6 operate. In this case, when the CGs 4-3 to 4-6 are accessed, the rasters 0 to y-1 when the standard CG 4-1 operates are CG 4-3 and the rasters y to 2y-1 are CG 4-5. Here, the access method of the CG is shown in FIGS. 15 (a) to (d).
This will be described below. In FIG. 15, (a) shows the operation order of CG4-1 and 4-2 in the case of the standard character display.
CG4-1 indicates CG4-2. Also in this case CG4
Assuming that each of -1 and CG4-2 can display one character, the font content is as shown in FIG. Next, the case of the enlarged display is shown in (b). In this case, CG4-3
Each of ~ CG4-6 requires the operation order of ~, and the font contents must also be as shown in (d).
Note that in (b), ~ indicates CG4-3 to 4-6.

Next, the scroll address is also written into the F / F 12 from the CPU 1. This output is added to the expanded address by ADD14 and output. FIG. 16 is an explanatory view of scrolling at the time of enlarged display. When it is desired to enlarge the portion shown in FIG. (A), write 0 in F / F12 to display the enlarged display of the portion when enlarged display is performed. (FIG. 16 (b)). Also, if you want to enlarge the part, the value of (2n-1) m is changed to F /
If you write to F12, it will be added to the expanded address by ADD14,
It is displayed (FIG. 16 (c)). Similarly, if it is desired to enlarge the portion, it is sufficient to write m and 2 nm respectively to the F / F 12 (FIGS. 16 (d) and (e)). In this manner, all of the standard characters can be displayed even in the enlarged display. Similarly, it can be used for vertical and horizontal enlargement.

To scroll up one line at a time, press F /
2m, 4m, 6m, ... 2m (n-1) should be written in order to F12, and when you want to scroll horizontally one character at a time, 1,2,3, ... m
Should be written sequentially. Furthermore, if you want the scrolling to be in the opposite direction, it is possible to reduce the value written to each F / F12.

On the other hand, FIG. 8 (b) is a block diagram showing a configuration of a character display device using a bitmap system. In FIG. 2B, the same reference numerals as those in FIG. 1A indicate identical components. Reference numeral 8 denotes a bitmap memory (hereinafter abbreviated as BMM) having a capacity corresponding to all bits of the CRT 6 and storing a character pattern of CG4.

 Next, the operation will be described.

The character code written into RM2 by CPU1 is output as a character pattern by CG4. The data is written to BMM8. The data of BMM8 read by CRTC3 is converted to 1-bit output by PS5, and
Output to T6. CRT6 displays this data on the display screen.

 When changing the display character, the following processing is performed.

 CPU1 rewrites the character code of RM2.

CPU1 accesses RM2 and outputs the character pattern of CG4.

 CPU1 reads the character pattern of CG4.

 CPU1 writes a character pattern to BMM8.

(Problems to be Solved by the Invention) However, the character display device having the above configuration has the following problems when used in a high-definition CRT or the like.

In the character type character display device shown in FIG.
As described above, there is a problem that the operation time is slow and the size of the character cannot be changed. This is solved by the character display device of FIG. 9 proposed by the present applicant. However, in the case of using a plurality of different fonts using these character methods, a plurality of character generators are required for each type of character, and a high-definition CRT is required to access a plurality of the same font CG at the same time. Since (species) × (plurality)｝ CGs are required, when displaying characters of other types, there is a disadvantage that a large capacity is required only by the character generator and the cost is increased.

On the other hand, in the case of using the bitmap method shown in FIG.
However, it was necessary to read RM2 and write the character pattern of CG4 to BMM8, which had a disadvantage that the load on CPU1 became large.

Further, in rewriting characters, when the CPU 1 has a 16-bit data bus, the following processing is performed for characters of 24 dots × 24 dots.

CPU1 writes the character code and the line number of the character to RM2.

CPU1 changes character pattern of RM2 character code from CG4 to 16
Read twice bit by bit.

Further, it is necessary to write the character pattern data into the BMM 8 corresponding to the screen of the CRT 6 2 × 24 = 48 times. As described above, there is a problem that it takes a lot of time and effort to rewrite the display in the bitmap method.

In addition, a character generator was required for each type of character.

An object of the present invention is that a plurality of types of character generators described above are required in plurality (character method).
And a character display device capable of instantly rewriting, enlarging, and scrolling a screen by eliminating a drawback (bitmap method) that takes too much rewriting time or requires a plurality of types of character generators. It is in.

(Means for Solving the Problems) In order to solve the above problems, a character display device according to the present invention includes a refresh memory for storing a character code, and a plurality of character generators for generating a character pattern corresponding to the character code of the refresh memory. Switching means for switching output signals of the plurality of character generators,
First conversion means for converting the signal of the character generator into a bit width at the time of horizontal enlargement and outputting the signal; the plurality of character generator signals from the first conversion means; A second method for changing the vertical and horizontal double widths of a character according to a control signal for instructing double-width magnification
A third converting means for directly outputting the character address to the refresh memory and the raster address to the character generator in the case of the standard character display, and converting and outputting the enlarged character display in the case of the enlarged character display. Means, timing control means for changing the operation timing of the refresh memory by changing the display clock in accordance with each of standard character display and enlarged character display, and specifying the address of the display screen and outputting it to the third conversion means. At the same time, in the case of an enlarged character, the address of the refresh memory is converted and output according to the enlargement, so that an area to be displayed at the time of enlarged display is designated by the display area designating means, the switching means or the second converting means. And a display means for displaying the character pattern on the display screen.

(Operation) The character display device configured as described above operates as follows. The refresh memory reads out the written character code and supplies it to a plurality of character generators. The character generator outputs a character pattern corresponding to the input character code to a switching unit, for example, a multiplexer, and also outputs to a first conversion unit, for example, a shift register. This first conversion means includes:
At the time of horizontal expansion, the signal of the character generator is converted into a bit width corresponding to the horizontal expansion, and second conversion means, for example, RO for expansion
Output to M. The second conversion means can convert the character pattern of the character generator from the first conversion means into a plurality of character patterns and display the enlarged character pattern on the display means. The switching means sequentially selects the output of the character generator other than at the time of horizontal enlargement, and continuously outputs the character pattern to the display means. On the other hand, the third conversion means outputs the character address to the refresh memory and the raster address to the character generator as they are in the case of the standard character display, and converts and outputs the character address and the raster address in the case of the enlarged character display. I do. Therefore, the screen can be rewritten and enlarged instantaneously without using a bitmap memory. Further, the display area designating means enables enlargement of the area to be enlarged and displayed simply by designating a specific address on the display screen, for example, the minimum address, so that scrolling at the time of enlargement can be easily performed.

(Example) Hereinafter, an example of the character display device according to the present invention will be described in detail.

FIGS. 1A and 1B are block diagrams showing the configuration of the character display device of the present embodiment. In FIG. 1, the same reference numerals as those in FIG. 9 denote components having the same structure. In the apparatus of this embodiment, CG4-3 to CG4-6 in FIG. 9 are removed, and instead, shift registers (SR) 15-1, 15-2 and ROM 13- are used.
2 and counters 16-1 and 16-2.
SR15-1 and 15-2 are provided as first conversion means for converting the outputs of CG4-1 and CG4-2 into bit widths at the time of horizontal enlargement, respectively. The output is input, and 3 bits of SR15-1 and 15-2 are output to the ROM 13-2 as the second conversion means. ROM13−
Reference numeral 2 inputs the SRs 15-1 and 15-2, and further receives an enlargement mode, a vertical enlargement, a triple magnification signal and an enlargement raster as control signals, and changes and outputs a character's vertical and horizontal double angles. That is, this ROM 13-2 operates in the horizontal enlargement mode,
Otherwise, it always outputs "0". The output of the ROM 13-2 is logically ORed with the output of the PS5 by an OR circuit and output to the CRT6. On the other hand, the MPX10-2 has a CS input added, and always outputs "0" in the horizontal enlargement mode. Otherwise, the inputs from the latch circuits 9-7 and 9-8 are the same as in the case of FIG. Output. Thus, in the horizontal enlargement mode (ie, 2x horizontal enlargement, 2x vertical / horizontal enlargement, 3x horizontal enlargement, 3x vertical / horizontal enlargement), the output of the ROM 13-2 remains unchanged, and in other modes (ie, standard, PS5 for 2x vertical and 3x vertical)
Is output to CRT6. Then, counters 16-1 and 16-2 are provided for 3 times horizontal enlargement, and are operated by 1 / 2CRTC clock and 1 dot clock, respectively.

On the other hand, the latch timing of the SRs 15-1 and 15-2 is the same as that of the latch circuit 9-7, but this signal is different from that in the horizontal enlargement mode and in other cases. CR from the oscillation circuit 7 in FIG.
An EOR (exclusive logical division) circuit is provided in place of the inverter circuit which inputs the TC clock and outputs it to the MPX10-3 and the latch circuits 9-5 and 9-7, and inputs the F / F12 and the clock. Except in the horizontal enlargement mode, the input becomes “1” from the F / F12 and acts as an inverter circuit for the clock. The same operation as in FIG. 9 is performed. In the horizontal enlargement mode, the F / F12 outputs “0”. Input,
The input clock is output as it is. That is, at the time of the horizontal enlargement, the counter 16-1 operating with the 1 / 2CRTC clock outputs a CRTC clock twice as large as the counter 16-1. As a result, the latch circuits 9-5, 9-
6 operates at the same timing in the horizontal enlargement mode. At the time of the three-fold horizontal enlargement, the counter 16-1 is 1 /
Generates a clock three times the 2CRTC clock.

2 (a) and 2 (b) show the address and raster conversion of the ROM 13-1 in the enlargement mode. The ROM 13-1 outputs a character address (hereinafter, referred to as an MA address) and a raster address (hereinafter, referred to as an RA address) as they are or after conversion, according to whether standard character display or enlarged character display is performed.

In FIG. 2, the output addresses of CRTC3 are 0-2mn-1,
The output raster is from 0 to y-1.
The MA address in the 2x horizontal enlargement mode is 0 to m-1,2m to 3m-
1,... 2m (2n-1) to (4n-1) m-1, and the RA address is repeated from 0 to y-1.

The MA address in the 2x vertical magnification mode is 0 to nm.
-1 and the same raster as the RA address from 0,0 to y-1 is output twice in succession and is repeated.

And, in the vertical and horizontal enlargement mode, the MA address is 0 to m−1,
0 ~ m-1,2m ~ 3m-1,2m ~ 3m-1, ... (2n-2) m ~ (2n
-1) The same row address as m-1, (2n-2) m to (2n-1) m-1 is output twice successively, and the RA address is also 0,0, to y-
The same raster as 1 is output twice, and this is repeated.

On the other hand, in the 3 × mode, in the case of the horizontal enlargement, the MA address is set to 0, 0, 0, to m / 3-1, m / 3-1, m / 3-1, m, m, m to 4 / 3m−
The output is repeated three times, such as 1. In the case of vertical enlargement, the addresses are 0 to m-1,0 to m-1,0 to m-1, m to 2m-
1 ... 2 (n-1) m / 3-2nm / 3-1 The same row address is output three times in a row, and the raster is also the same as 0,0,0-y-1, y-1, y-1 Output the raster three times and repeat.

Then, at the time of vertical and horizontal expansion, the MA address is 0,0,0 to m / 3−1,
The same address as m / 3-1, m / 3-1, m, m, m to 4 / 3m-1, ... is output three times in succession, and the RA address is 0,0,0 to y-1, y−1, y
The same raster as -1 is output three times, and the process is repeated. The two outputs of the enlarged raster (output from the ROM 13-1 in FIG. 1 and input to the ROM 13-2) always output "00" in the standard mode and the vertical enlargement mode, and are twice as wide and vertically and horizontally. At the time of double, 0 or 1 of “00” or “01” is output. This is the same as the even and odd raster addresses. Then, at the time of triple and vertical / horizontal enlargement, 1 to 3, such as "01", "10", and "11", are output. This is the RA address divided by 3 plus one.

The operation in the standard mode is the same as in the case of FIG.

FIGS. 3A to 3H show the address of each character when displaying standard characters, the address of CRTC, and the address of each character when displaying enlarged characters. FIG. 3 (a),
(B) and (e) are similar to FIGS. 13 (a), (b) and (c) respectively, and FIGS. 3 (c), (d),
In (f) to (h), the number of horizontal characters and the number of vertical characters are determined according to each enlargement mode.

Next, the display character pattern at the time of enlargement is shown in FIG.
(B). In this case, one character of CG4-1 is 20 dots wide and 24 dots high, and the display area of CRT6 is 640 dots wide and
480 dots vertically. Note that only the composite pattern (i) in FIG. 4 (b) has a signal between the display ON signals “1” and “1” as “0” in the space display as shown in FIG. It was done.

FIG. 5 shows the output of the ROM 13-1 in the standard, horizontal enlargement, vertical enlargement, and double-width (vertical and horizontal enlargement) modes.
In this case, 640 ÷ 20 = 32 characters horizontally and 480 ÷ 24 = 20 lines vertically. That is, the display characters are 32 × 20 = 640 characters.
Therefore, address MA is 0-639, raster is 0-23,
Or, if the non-display area is a 5-character sentence, the characters of one line sentence by CRTC3 are 37 characters and the display area is 32 characters.
Among them, the display ON signal becomes “1” in the display area and CR
Character display becomes possible on T6. The output of the CRTC3 is converted by the ROM 13-1 into a standard, double or triple horizontal enlargement, double or triple vertical enlargement, double or triple vertical and horizontal enlargement. RO
CGON signal output of M13-1 output is "0" when space
CG4-1 and CG4-2 are set to output all “0”.

The power of the ROM 13-1 includes MA, raster addresses, and signals from the F / F 12 that are vertically enlarged, horizontally enlarged, and tripled. The F / F 12 further outputs an address and double-width mode signals 1 and 0. In the enlargement mode (horizontal enlargement and vertical enlargement), the MPX 10-3 selects the ADD 14-1 side in which the address data of the F / F 12 is added to the address of the ROM 13-1, and accesses the RM2 from the MPX 10-1. RM2 outputs the character code of the given address. The CGs 4-1 and 4-2 output a character pattern from the code and the raster address of the ROM 13-1. On the other hand, CG4-
2 outputs a character pattern in which the raster is shifted by one line by ADD14-2 during horizontal enlargement.

The character patterns of the CGs 4-1 and 4-2 are output to the SR15- at the same timing by the latch circuits 9-5 and 9-6 by the clocks having the same phase at the above-mentioned EOR by the horizontal enlargement signal "0".
1, 15-2. The SRs 15-1 and 15-2 are latched by a clock having the same phase as that of the latch circuit 9-5 and shifted by a two-dot clock output from the oscillation circuit 7. Here, CG4-1 and CG4-2 have a 16-bit pattern width, but are input as 20-bit patterns by SRs 15-1 and 15-2. The details are shown in the input / output explanatory diagram of FIG. 6 (a) and the operation explanatory diagram of FIG. 6 (b). As shown in FIGS. 6 (a) and 6 (b), the SR has 22 inputs I0 to I21 and three outputs O0 to O2. SR is I0 to I21 when CP input becomes "1"
And outputs the data of I0 to I2 to O0 to O2. This data corresponds to N-1, N, N + 1 of the ROM 13-2,
They are XN-1, XN, XN + 1 and YN-1, YN, YN + 1, respectively. RO
In addition to these inputs, M13-2 receives the two outputs of the counter 16-2 and three times the mode signal. The counter 16-2 operates as a quaternary counter except in the triple mode, and operates as a ternary counter in the triple mode. RO
The contents of the code conversion of M13-2 are shown in FIGS.

Thus, double-width characters having different character fonts can be displayed only by changing the power of the enlargement circuit.

(Effect of the Invention) As described in detail above, according to the present invention, a character can be enlarged twice or three times using a standard character generator without using a bitmap memory, It is also possible to make characters easier to see by changing the dot arrangement that forms. From the above, enlarged characters of 4 times and 5 times can be obtained. Thus, a display character conversion device that is inexpensive and does not impose a burden on the CPU can be provided.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) show a single figure as a unit, and are block diagrams showing the configuration of an embodiment of the character display device according to the present invention, and FIGS. 2 (a) and 2 (a). 2) and FIG. 2 (b) show one figure as a whole. FIG. 3 (a) to (h) show the addresses of the ROM 13-1 and the raster conversion in the enlargement mode. FIG. 4 (a) and FIG. 4 (b) show a character address, a CRTC address, an enlarged character address, and FIG. Figure 5 shows the standard,
ROM1 in horizontal, vertical and double-width (vertical and horizontal) modes
FIG. 6 (a) shows the output of 3-1.
FIG. 6 (b) is an operation explanatory view of FIG. 6 (a), and FIGS. 7 (a) and 7 (b) show one figure in an integrated manner. FIGS. 8 (a) and 8 (b) are diagrams showing a configuration example of a conventional character display device, and FIGS. 9 (a) and 9 (b) are diagrams showing a configuration example of a conventional character display device. Improved character type character display device,
FIG. 10 is a timing chart of the apparatus shown in FIG. 9, FIG. 11 is an explanatory diagram of the operation of the apparatus shown in FIG. 9, and FIG. 12 shows conditions of standard characters and enlarged characters used in the description of the apparatus shown in FIG. Fig. 13
The figure shows the standard character address, CRTC address,
FIG. 14 is a diagram showing an enlarged character address, FIG. 14 is a diagram showing character address and raster address conversion of the device of FIG. 9, FIG. 15 is an explanatory diagram of a CG access method of the device of FIG. 9, and FIG. 9
It is explanatory drawing of the scroll of the enlarged display of the apparatus of a figure. 1 Central processing unit (CPU), 2 Refresh memory (RM), 3 CRT controller (CRTC), 4-1, 4-
2 ... Character generator (CG), 5 ... Parallel-serial conversion circuit (PS), 6 ... CRT, 7 ... Oscillation circuit, 8 ... Bitmap memory (BMM), 9-1 to 9-
8 Latch circuit, 10-1 to 10-3 Multiplexer (MPX), 11 Bus buffer, 12 Flip flop (F / F), 13-1 to 13-2 Read-only memory (R
OM), 14-1 to 14-2 ... Adder (ADD), 15-1 to 15
-2: Shift register (SR), 16-1 to 16-2 ... Counter.

Claims (1)

(57) [Claims] (A) a refresh memory for storing a character code; (b) a plurality of character generators for generating a character pattern corresponding to the character code of the refresh memory; and (c) switching output signals of the plurality of character generators. Switching means; (d) first converting means for converting the signal of the character generator into a bit width at the time of horizontal enlargement and outputting; and (e) signals of the plurality of character generators from the first converting means and characters. Second conversion means for changing and outputting the character's vertical and horizontal magnification by a control signal for instructing double-width magnification such as standardization, enlargement, and vertical / horizontal magnification; (f) character address to refresh memory and raster address to character generator Is output as it is for standard character display, and is converted to (G) timing control means for changing the operation timing of the refresh memory by changing a display clock according to each of standard character display and enlarged character display, and (h) display screen. A display area for designating an area to be displayed at the time of enlarged display by designating an address and outputting it to the third converting means, and in the case of an enlarged character, converting and outputting the address of the refresh memory according to the enlargement and outputting the address. (I) display means for displaying a character pattern from the switching means or the second conversion means on a display screen.