JPH0540553Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a character display device used, for example, when displaying text or the like on a display unit of a copying machine or a facsimile machine.

"Prior Art" For example, copying machines have been equipped with microcomputers, which have enhanced their functions, making it possible to respond more precisely to the various demands of operators. However, on the other hand, a situation may arise in which a person who is unfamiliar with the model to be used is confused about its operation. Therefore, recent efforts have been made in copying machines to display information necessary for operation in the form of text or the like on the display section to assist the operator's operation.
Information is displayed using a combination of symbols such as kanji, katakana, hiragana, alphanumeric characters, numbers, or symbols. For example, when the developing toner runs out, a message such as "Please replenish toner" will be displayed on the display section.

By the way, in such a copying machine, for example, when a certain text needs to be displayed, a text/figure storage means (hereinafter referred to as a ROM (read-only memory) for storing text) is used to store various texts as code strings. (This is called a text ROM.) The code string corresponding to the text is read out. Here, the code string refers to a code that has been assigned in advance to each mark as a constituent element of a text or figure, arranged in the order of the text, etc. to be displayed. When displaying the above-mentioned sentences, a code string includes a code for "g", a code for "na", a code for "-", etc.

Now, each code corresponds to a mark code data table for specifying the pattern of each mark. For example, if this mark code data table is composed of address information of 4 bits vertically and horizontally (total 1 byte) as shown in Figure 5, the number of marks that can be specified by this is 2 ⁴ ×2 ⁴ i.e. maximum
There are 256 ways. In other words, if each code that specifies a mark is made up of one byte, a maximum of 256 types of marks can be displayed. If the end code indicating the end of the sentence is included in the sentence ROM along with these marks,
If the mark is placed within the above range, the number of marks that can be used will be reduced by 1 to 255.

``Problem that the invention attempts to solve'' If we try to display an easy-to-understand sentence by appropriately selecting and using many sentences and kanji, the number of kanji marks, etc. to be prepared will exceed the 255 or 256 types mentioned above. I will cross it. However, if this limit is exceeded, the number of bits that make up the code for identifying the mark must be increased. For example, if this code is made up of 2 bytes, it is possible to specify 2 ⁸ × 2 ⁸ , or more than 65,000 marks. However, identifying such a large number of marks is not necessary with simple character display devices used in copying machines, etc., and this increases the amount of memory required for the text ROM, requiring a large memory capacity. There is also the problem of having to use .

Furthermore, Japanese Patent Application Laid-Open No. 1983-60490 discloses a technique in which a character generator for alphanumeric/kana characters and a character generator for kanji are provided, and the character generators are switched using a special code. . According to this technology, alphanumeric characters and kana characters are represented by a 1-byte display code, and kanji characters are represented by a combination of a special code and a 1-byte display code, so the number of bits in the code that specifies the kanji character increases. , the number of bits for alphanumeric characters and kana characters can be reduced.

However, even when this technique is used, in the case of a device whose display content includes many Chinese characters, there is still a problem that the amount of storage required for the text ROM increases.

Therefore, an object of the present invention is to provide a character display device that can reduce the memory capacity for storing display contents such as various texts and figures.

"Means for Solving Problems" In the present invention, the mark code data table is structured into multiple pages, and frequently used marks are placed on the first page. For marks associated with pages after the second page, a code twice the length of the code for the mark placed on the first page is used. The first code is used to specify the "code for specifying the second and subsequent pages" on the first page, and the second code is used to specify the mark on the corresponding page.

Practically speaking, if approximately 500 types of marks are used, the mark code data table should consist of two pages, and each page should contain 1 byte of code data so that the mark can be searched for.

According to the present invention, codes for frequently used marks can be set substantially shorter, so text/figure storage means such as text ROM can be used efficiently, allowing more texts to be stored. be able to.

"Example" The present invention will be described in detail with reference to Examples below.

FIG. 1 shows a schematic configuration of a character display device according to the present invention. This character display device is equipped with a CPU (Central Processing Unit) 11, and each part is controlled by a bus 12. Among these, the control ROM 13 contains a program to control this character display device.
It is ROM (read only memory). Font ROM14 memorized the font of each character.
It is a ROM. The text ROM 15 is a ROM that stores various texts to be displayed on a display (not shown) connected to the display controller 16. The display controller 16 is a circuit that performs control to display characters and the like on this display. Display RAM1
7 is for writing the character pattern to be displayed.
RAM (Random Access Memory).
The working RAM 18 is for temporarily storing data necessary for operating this character display device.
It is RAM.

FIG. 2 shows a character code data table (emblem code data table) used in this character display device. The character code data table consists of two pages. The first page 1P stores character code data for relatively frequently used characters, and the second page 2P stores characters for other characters. Code data is stored. In both pages 1P and 2P, a search for a corresponding character is performed using address information of 4 bits each in length and width (0 to F in hexadecimal).

On the first page of the character code data table, the second page designation code a is placed as a control code at the FE address expressed in hexadecimal, and the end code b is placed as the control code at the adjacent FF address. ing. Therefore, this first page 1
The total number of character codes arranged in P is 254, which is 256 minus 2. There is no need to arrange such control codes on the second page of the character code data table, and a maximum of 256 character codes can be arranged.

The operation of selecting characters by this character display device will be explained using FIG. First, CPU11 is
When a request to display a predetermined sentence occurs, a series of codes for the corresponding sentence are read out from the sentence ROM 15 (step). Text ROM1
5, various sentences are stored in hexadecimal numbers.

Now, as shown in FIG. 4, it is assumed that a series of codes such as "...30 2E 30 FE 20 50 F0 FF" are read from the text ROM 15 and the contents are stored in the working RAM 18. When the code "30" is read from the working RAM 18, the CPU 11 determines whether this code is the "FE" code corresponding to the second page designation code a on the first page of the character code data table. (step). Since this is not the case, the CPU 11 then determines whether the read code is an "FF" code corresponding to end code b (step). Since this is also not applicable, in this case, a character matching the code "30" is selected from the first page 1P of the character code data table (step). In this case,
From FIG. 2, the character "Z" is selected. The pattern of the selected character “Z” is font ROM1.
4 and stored in the corresponding area of the display RAM 17.

When the above work is completed, the next code "2E" is read out from the work RAM 18 (step). In this case, do the same (step ~
) The character "X" is selected and its pattern is written into the display RAM 17. The same goes for the next code "30".

Thereafter, the code "FE" corresponding to the second page designation code a is read from the working RAM 18. In this case, since the step condition is satisfied, the next code "20" is further read out (step). In this case, the second page 2P of the character code data table is searched for the character corresponding to the code "20" (step). As a result, the character "Q", for example, is selected and its pattern is written into the display RAM 17.

The corresponding characters are searched from the read code in the same way, and the character pattern is displayed.
It will be written to RAM17.

When the code "FF" corresponding to the end code b is read out from the working RAM 18, the condition of the step is satisfied, so the reading operation is completed.

Above, we have explained the case where the character code data table has 2 pages, but if there are 3 pages, for example, by placing a control code to specify the 3rd page on the 1st page, even more characters etc. In contrast, the text ROM can be used efficiently. The same applies when four or more pages of character code data tables are provided.

Furthermore, in the embodiment, a case has been described in which text is displayed by selecting characters, signals, etc., but it is also possible to display a desired figure by combining symbols as various constituent elements, and the present invention is applicable to such cases. It is also effective in cases where

Furthermore, in the example, an end code was used as a control code, but this is used for short sentences.
This is to save the area used in ROM. Therefore, it is natural that there is no need to use this end code if the length of the sentence is set to be constant.

``Effect of the invention'' As described above, according to the invention, even if the types of marks such as characters used increase to a certain extent, the codes for frequently used marks can be set short, so that various types of text can be used. The memory capacity for storing display contents such as graphics and figures can be minimized, and the device can be configured at a correspondingly low cost.

[Brief explanation of the drawing]

Figures 1 to 4 are for explaining one embodiment of the present invention, of which Figure 1 is a block diagram showing the main parts of a character display device, and Figure 2 is an explanatory diagram of a character code data table. , Figure 3 is a flowchart showing the operation of this device, Figure 4 is an explanatory diagram showing the relationship between part of the contents of the text ROM and the character code data table, and Figure 5 is a diagram showing the conventionally used mark code. It is an explanatory diagram of a data table. 13... Control ROM, 14... Font ROM, 15... Text ROM, 1P... First page of character code data table, 2P... Second page of character code data table.

Claims (1)

[Claims for Utility Model Registration] 1. Using a mark code data table that shows the relationship between individual marks such as letters, symbols, etc. and the codes corresponding to each mark, a mark corresponding to the indicated code is selected. a mark pattern generating means for searching and generating the pattern; a text/figure storage means for storing code strings necessary for displaying each display information such as text and figures expressed by the combination of the marks; and a display. A code string corresponding to the content is read from the text/figure storage means, and each code in the code string is given to the mark pattern generation means to generate a mark pattern corresponding to each code and display it on the display section. In the character display device equipped with a display control means, the mark code data table consists of a plurality of pages, and each address of the first page is assigned a frequently used mark, and each address of the second and subsequent pages is assigned a frequently used mark. Another mark is assigned to the street address, and in the code string stored in the text/figure storage means, the code corresponding to the mark assigned to the first page corresponds to that mark on the first page. The code corresponding to the mark assigned to the second page and subsequent pages is represented by the combination of the page instruction code indicating that page and the address corresponding to the mark on that page. If the code read from the text/figure storage means includes a page designation code, the display control means specifies the page designated by the page designation code, to the mark pattern generation means. However, in other cases, the first page is specified. 2. The mark code data table consists of two pages, and the address of each page is represented by one byte, and no mark is assigned to a specific address on the first page, and that address points to the second page. 2. The character display device according to claim 1, wherein the character display device has a page instruction code.