JP2956774B2 - Character display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a character display device for displaying characters, symbols, simple figures, and the like (in this specification, these are simply referred to as characters), and more particularly to reading out bit string data corresponding to character codes.

[Prior art]

A raster scan type character display device generally used as this type of character display device is configured as shown in FIG. In FIG. 4, reference numeral 20 denotes a control circuit including a microprocessor for controlling the entire apparatus. Reference numeral 21 denotes a storage circuit in which a character code is stored, which is a so-called video RAM. In this case, as shown in FIG. 5, a storage device corresponding to the display position on the display screen
A character code (for example, 8 bits) corresponding to a character (for example, A, B, C, D) is written in each of the addresses 21 (for example, addresses n to n + 3). Reference numeral 22 denotes a character generator that stores a bit string for displaying a character corresponding to a character code on a display screen. In this case, for example, in the case of FIG. 6, one character is composed of 8 lines × 8 pixels on the display screen, and the character generator 22 assumes that one pixel corresponds to one bit. Is, for example, as shown in FIG.
For example, 8-bit data is written for each line of one character. Reference numeral 23 denotes a display circuit having a display having a display screen as shown in FIG. The control circuit 20 can read and write the contents of the character code storage circuit 21 via the data bus 1 and the address bus 2. The timing generation circuit 24 gives an address 3 in units of characters to the storage circuit 21, an address 4 in units of one line on the display screen (hereinafter referred to as a raster address) to the character generator 22, and a display unit 23. Gives a clock 8 in bit units. The character codes are sequentially read out from the storage circuit 21 by the addresses 3 and 4 and the clock 8 from the timing generation circuit 24, and the bit sequence 7 is output from the character generator 22 in accordance with the read character code output 5. Is generated, and the display circuit 23 displays it one bit at a time in the line direction. As a result, characters are displayed on the display screen in accordance with the contents of the storage circuit 21. By the way, in this character display device, when the data displayed on the display of the display circuit 23 is read and the hard copy is obtained by a hard copy device such as a graphic printer, the hard copy is obtained from the control circuit 20. The address (address) of the character code unit of the area on the screen to be output is output to the storage circuit 21, and the character code is read from the storage circuit 21. Then, the control circuit 20
Send the character code to the printer. And
In the printer, the character code is supplied to a character generator provided in the printer, and bit string data is read out from the character generator and printed on recording paper. However, in this method, the character code of the character generator provided in the printer must correspond completely to the character code of the character generator of the character display device. There is a problem that a copy cannot be taken. Therefore, a character display device as shown in FIG. 8 has been proposed. In this example, another character generator 25 having the same contents as the character generator 22 is provided and connected to the control circuit 20. Character display on the display screen of the display circuit 23 in this example can be performed using the character generator 22 in exactly the same manner as in the example of FIG. Further, even when the character codes of the printer correspond one-to-one with the character codes of the character display device, it is possible to take a hard copy in exactly the same manner as in the example of FIG. However, in this example, considering the case where the character code of the character generator of the character display device does not correspond to the character code of the character generator of the printer, as shown in the flowchart of FIG.
Gives an address of a character code unit of an area on the screen where a hard copy is to be taken to the storage circuit 21, thereby reading the character code from the storage circuit 21. Then, the control circuit 20
Applies data 9 including the read character code and an address for reading the bit string data corresponding to the character code to the character generator 25, and obtains the corresponding bit string data 10 from the character generator 25. Then, the control circuit 20 sends the bit string data to the printer to obtain a hard copy of the character. In this case, a printer capable of graphic printing is used as the printer. By the way, in the example of FIG. 8, the character generator 22 and the character generator 25 have the same contents, so that one character generator can also be used. FIG. 10 shows an example of such a case. That is, in the case of this example, the code switching circuit 26
, An address switching circuit 27 is provided at a stage preceding the code input terminal and the address input terminal of the shared character generator 22. And a character code output 5 from the storage circuit 21;
The character code of the data 9 from the control circuit 20 is switched by the code switching circuit 26 according to the switching signal from the control circuit 20. Further, the raster address 4 from the timing generation circuit 24 and the address for reading the bit string data corresponding to the character code of the data 9 from the control circuit 20 are changed by the switching signal from the control circuit 20 to the address switching circuit. Switch with 27. That is, in the case of this example, when the character code of the character display device does not correspond to the character code of the printer, the control circuit 20 determines the character code of the character on the screen for which a hard copy is to be obtained from the storage circuit 21. Is read. Then, the switching circuits 26 and 27 are switched to the character code and the raster address from the control circuit 20, respectively, and the character code and the raster address are applied to the character generator 22, and the corresponding bit string data 10 is obtained from the character generator 22. Then, the control circuit 20 sends the bit string data to the printer to obtain a hard copy of the character. In the example of FIG. 10, the display operation on the display circuit 23 is the same as that of FIG.

[Problems to be solved by the invention]

However, in the case of the example shown in FIG. 8, two character generators must be provided, and the control circuit 20
Temporarily reads the character code stored in the storage circuit 21 and sets an address for reading out the character code and the bit string data corresponding to the character code, whereby the bit string corresponding to the character code is read from the character generator 25. There is a problem that reading must be performed, processing becomes complicated, and software (program) of the control circuit 20 becomes complicated. Further, in the case of the example of FIG. 10, only one character generator is required. However, as in the example of FIG.
It is necessary to read the character code stored in the storage circuit 21 once, set the character code and the raster address for the character generator 22 from this character code, and switch the switching circuits 26 and 27. For this reason, there is a problem that the processing procedure on the software is also complicated. The present invention has been made in view of the above-described drawbacks, and has as its object to provide a character display device that can read character pattern data to be transferred to a printer with a simple configuration.

[Means for Solving the Problems]

In the character display device according to the present invention, for example, when correspondence is given to FIG. 1 (corresponding block numbers are shown in parentheses), the characters are displayed on the display screen at respective addresses corresponding to the display positions on the display screen. Storage means (21) for storing one or more character codes corresponding to one or more characters, and storing bit string data of a character pattern corresponding to each of the plurality of displayable character codes, Character pattern data generating means for receiving a character code from the storage means, determining a character pattern to be output, and outputting bit string data of a character pattern corresponding to the determined character code in accordance with a read address signal of the character pattern (22) Switching means (28) for switching a read address signal of the character pattern supplied to the character pattern data generating means; Display means (23) having the display screen for displaying a bit string; and sequentially reading out one or more character codes corresponding to one or more characters displayed on the display screen stored in the storage means. For this purpose, while sequentially supplying an address in character code units to the storage means, and for display on the display means, the character pattern data generation means transmits the character pattern read address signal through the switching means to the character pattern data generation means. A timing signal generating means (24) for supplying, and an address in a character code unit of an area on the display screen where a hard copy is obtained by a printer to the storage means. The code is output to the character pattern data generating means, and is used for reading data to be transferred to the printer. A read address signal of the character pattern is supplied to the character pattern data generating means through the switching means. At this time, bit string data output from the character pattern data generating means is obtained, and the bit string data is sent to a printer. Control means (20) for transferring, and the switching means (28) is provided with the control means (2
It is characterized by being able to switch based on the signal from 0).

[Action]

In the present invention having the above-described configuration, the address of the character code unit of the area on the screen where the hard copy is desired to be obtained by the printer from the control means (20) is given to the storage means (21). Then, the character codes of the characters displayed in the above-mentioned area on the screen are sequentially read from the storage means (21). This character code is supplied to character pattern data generating means (22). Further, at this time, a character pattern read address signal is supplied from the control means (20) to the character pattern data generating means (22) through the switching means (28), so that the character pattern data generating means is provided. From (22), the bit string data of the character pattern of the display character in the area is read. The control means (20) receives this bit string data,
Transfer to printer. That is, the character pattern data to be transferred to the printer can be obtained by simply setting the corresponding address of the storage means in the same manner as a general procedure for reading data on a so-called bitmap display. Therefore, there is a feature that software for reading character pattern data to be transferred to the printer can be simplified.

【Example】

FIG. 1 is a block diagram of one embodiment of a character display device according to the present invention. In FIG. 1, the fourth
The same reference numerals are given to portions corresponding to those in the example of the drawing, and detailed description thereof will be omitted. In this example, an address switching circuit 28 is provided. In this example, the bit string data 7 from the character generator 22 is also supplied to the control circuit 20. Others are the same as the example of FIG. The address switching circuit 28 converts the raster address 4 for display from the timing generation circuit 24 and the address from the control circuit 20 for reading out bit string data corresponding to the character code as data to be transferred to the printer. The address is switched to be supplied to the character generator 22 as the address 11. The switching of the address switching circuit 28 may be performed by the control circuit 20, or may be switched by the address switching circuit 28 detecting that the value of the address is an address for reading bit string data. During a normal display operation, the address switching circuit 28 is switched to supply the raster address from the timing generation circuit 24 as the address 11 to the character generator 22. When reading the bit string data, switching is performed so that the address from the control circuit 20 is supplied to the character generator 22 as the address 11. In this case, specifically, on the display screen, as described above,
In the case where the data is composed of 8 lines per character, of the 16-bit addresses A0 to A15 from the control circuit 20, the address 2 connected to the storage circuit 21 is A0 to A9, and is connected to the address switching circuit 28. Address 2 is A10 to A12. Each line address of a character pattern for eight lines is specified by the 3-bit addresses A10 to A12. Also,
When the address switching circuit 28 detects reading of bit string data, A13 to A15 are also connected. Then, when A15, A14, and A13 of the address 2 are “100”, the control circuit 20 can read and write the storage circuit 21 through the data bus 1, and
When A15, A14, and A13 are "101", bit string data can be read. Control circuit 20 in this case
FIG. 3 shows the relationship between the address and the screen as viewed from the side. In this example, the normal read operation is the same as in the example of FIG.
4 and the clock 8, the character code is sequentially read from the storage circuit 21 from, for example, the upper left corner of the screen, the bit string data corresponding to the display character pattern on the screen is read from the character generator 22, and the display circuit 23 A character pattern image corresponding to the storage content of the storage circuit 21 is obtained on the display screen of FIG. Further, the operation of writing and reading the character code from the control circuit 20 to the storage circuit 21 is the same as the conventional operation. Next, when obtaining a hard copy of a character pattern at an arbitrary position on the screen, the following is performed. That is, the operation in this case will be described with reference to the flowchart of FIG. 2. First, the control circuit 20 sets the character code corresponding to the display character position in an arbitrary area on the screen where it is desired to obtain a hard copy. The unit address is supplied to the storage circuit 21, and an address for reading out the bit string data corresponding to the character code from the character generator 22 is output to the address switching circuit 28. Next, the address switching circuit 28 is connected to the control circuit 20.
Is switched to the output address 11 side. It should be noted that the address switching circuit 28
When switching is performed upon detecting that 5, A14 and A13 are "101", this switching process is unnecessary. Then, a character code is read from the corresponding address from the storage circuit 21, and the read character code is given to the character generator 22. At this time, the character generator 22 sends the address 11 as the control circuit 20
, The bit string data corresponding to the character code is obtained from the character generator 22 and is taken into the control circuit 20. Then, the control circuit 20 transfers the bit string data to the printer. A printer capable of graphic printing is used. Then, the printer transmits the bit string data (for example, eight lines for one character) to 1
By embossing eight lines in correspondence with bit-1 pixel, a hard copy of a character pattern corresponding to the character code can be obtained. As described above, the control circuit 20 merely supplies the address of the character code unit of an arbitrary area on the screen on which a hard copy is desired to be taken to the storage circuit 21, and the arbitrary circuit on the screen is provided. The bit string data of the character pattern at the position can be read. That is, the character display screen can be read as bitmap data. In the above example, the display circuit uses a raster-scan type display. However, the present invention is not limited to this, and a matrix display device such as an LCD can be used.

【The invention's effect】

As described above, according to the present invention, when obtaining the bit string data of the character pattern on the display screen, the control circuit 20 once reads out the character code from the storage circuit 21 and supplies the character code to the character generator. Instead of just setting the address at any position on the screen where you want to make a hard copy, you can read the bit string data of the character pattern at any position on that screen. Can be read as bitmap data. Therefore, the bit string data of the character pattern at an arbitrary position on the screen can be read by a simple processing procedure. For this reason, even when a special character generator that does not have a one-to-one correspondence with a printer is used as a character generator, a printer capable of graphic printing can easily print the display screen as it is.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a character display device according to the present invention, FIG. 2 is a flowchart for explaining the operation, FIG. 3 is a diagram showing the relationship between the address and the screen, FIG. FIG. 5 is a block diagram of an example of a conventional character display device, FIGS. 5 and 6 are diagrams for explaining the same, FIG. 7 is a diagram for explaining a display screen, and FIG. FIG. 9 is a block diagram of another example of the character display device, FIG. 9 is a flowchart for explaining the operation thereof, and FIG. 10 is a block diagram of still another example of the conventional character display device. 20; control circuit 21; storage circuit 22; character generator 23; display circuit 25; timing generation circuit 28; address switching circuit

Continuation of front page (56) References JP-A-56-124944 (JP, A) JP-A-58-208836 (JP, A) JP-A-55-150065 (JP, A) JP-A-59-135540 (JP) , A) Japanese Utility Model Showa 63-43256 (JP, U)

Claims (1)

(57) [Claims] 1. A storage means for storing, at each address corresponding to a display position on a display screen, one to a plurality of character codes corresponding to one to a plurality of characters displayed on the display screen, The data of the bit string of the character pattern corresponding to each of the plurality of character codes is stored, the character code from the storage unit is received, the character pattern to be output is determined, and the character pattern read address signal is used. A character pattern data generating means for outputting bit string data of a character pattern corresponding to the determined character code; a switching means for switching a read address signal of the character pattern to be supplied to the character pattern data generating means; and displaying the bit string. A display unit having the display screen, and a display unit displayed on the display screen stored in the storage unit. In order to sequentially read out one or a plurality of character codes corresponding to one or a plurality of characters, an address in a character code unit is sequentially supplied to the storage means, and for displaying on the display means, A timing signal generating means for supplying a read address signal of the character pattern to the character pattern data generating means through the switching means; and a character code of an area on the display screen on which a hard copy is obtained by a printer for the storage means. By giving a unit address, the character code of the area is output from the storage means to the character pattern data generating means, and the character pattern data generating means is read to the character pattern data generating means for reading data to be transferred to a printer. A pattern read address signal is supplied through the switching means, Control means for obtaining bit string data output from the character pattern data generating means and transferring the bit string data to a printer, wherein the switching means switches based on a signal from the control means. Character display device.