JPS6147428B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling character patterns, and more particularly to a method for controlling character patterns in a kanji output device connected to a terminal control device (hereinafter referred to as TCE).

Kanji patterns are output to known CRT display devices, non-impact printers, and the like. The generation of kanji patterns in such a kanji output device is more complicated to control than the generation of other character patterns, such as alphanumeric patterns. This is due to the fact that there are far more types of kanji than alphanumeric characters, and the patterns of kanji are more complex.

As conventional kanji pattern control methods, there are several types of control as follows.

The first control method is the simplest one, and uses the character pattern generator (hereinafter simply CG) in the kanji output device.
) stores all character patterns including kanji. This method has the advantage that it takes less time to output character patterns than the method described below, but the memory capacity increases dramatically due to an increase in the number of characters to be handled or an increase in the pattern structure of one character. There is a drawback.

The second method is to use commonly used character patterns (for example, JiS 1st level kanji 3455
There is a method in which character patterns (types) are permanently resident in the CG of a kanji output device, and infrequently used character patterns are replaced and stored each time in a specific area within the CG or in a separate CG.

Although this method does not require a large increase in memory due to an increase in the number of characters or fonts compared to the first method, it has the disadvantage that it has a considerable amount of unnecessary CG for the characters being displayed.

As the third method, as shown in Figure 1,
External buffer 1 serves as an interface interface with TCE, and display data is registered in kanji code, and internal buffer 1 of the kanji output device
An internal code buffer 2 is provided in which codes converted to CG addresses are registered, and a CG memory 3 corresponding to the maximum number of display characters and kanji codes are stored in the internal CG.
CG by managing table 4 to convert to address
There are ways to save memory.

In the management table 4 of this system, addresses corresponding to the maximum number of display characters are assigned, and each address becomes a CG address for a display character. Furthermore, the contents of table 4 are set with the kanji code of the CG font registered in the CG address.
As a normal processing operation, it is checked whether the kanji code a read from the external buffer 1 is registered in the CG memory 3. That is, set the kanji code a in the check circuit 5, repeat the check to see if the same code exists from the first address to the last address in the table 4, and if the same code exists, the address SAj with the matching code is set to the kanji code a. Register the CG address for the internal buffer at the same location as the external buffer.

If there is no matching code after searching up to the final address, it means that the corresponding character pattern has not been registered in the CG memory 3, and in this case, the corresponding character pattern is loaded from the TCE.

In this case, when registering the character pattern in the CG memory, the next address of the kanji code registered at the end of table 4 is assigned. However, when Table 4 is completely filled, it is necessary to detect character patterns that are not currently required for display in this method. This is done through the check circuit 5, and the check is repeated from the start point to the end point to detect unnecessary CG addresses.

Therefore, in this method, the check circuit 5 becomes complicated and requires many logic elements.

SUMMARY OF THE INVENTION An object of the present invention is to provide a character pattern control system that eliminates the need for the above-mentioned check circuit and its complicated logic circuit, and that does not reduce the character pattern processing ability.

Therefore, the present invention improves the conversion process from kanji code to internal CG address by using a microprocessor and changing the table processing method. This is to prevent a decrease. To this end, the present invention has an external buffer that stores display data as a character code (for example, a kanji code), and an internal computer buffer that stores the character code.
An internal buffer that converts the code into an address and stores the converted code as an internal code, manages whether a character pattern corresponding to the character code is registered in the CG memory, and reads the character code as an address. a first table for storing CG addresses to be displayed, a CG memory for registering character patterns for the maximum number of characters to be displayed on one screen, and whether or not the character patterns registered in the CG memory are currently being used for display. and a microprocessor for converting character codes into internal codes and managing the first and second tables.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. FIG. 2 shows the generation of character patterns in a kanji display device.

Referring to FIG. 2, display data is registered in the external buffer 1 in Kanji code. When registering, a write command is issued from the kanji display device to the TCE (not shown), and the kanji code is received from the TCE and stored. The kanji code registered in external buffer 1 is the internal kanji code in the kanji display device.
It is converted into a CG address, and this converted internal code is registered in the internal buffer 2. Conversion from external code to internal code is performed by microprocessor 15. The CG memory 3 stores character patterns and has a storage capacity corresponding to the maximum number of characters displayed on one screen of the display device. CG memory 3 stores character patterns corresponding to the maximum number of characters that can be displayed on one screen.
Although the capacity of the CG memory itself can be saved, since the display contents change sequentially, it is necessary to replace the character patterns in the CG memory 3. This operation is performed by the microprocessor 15, and the details will be described later.

Table 6 is a table that manages whether or not a character pattern corresponding to a kanji code is registered in the CG memory 3. Address KAa corresponding to kanji code a in table 6 is referenced for the character pattern of kanji code α. However, if a character pattern exists in CG memory 3, it will be used as a CG address.
SAj is output. On the other hand, if the character pattern does not exist in the CG memory 3, specific information that cannot be assigned as a CG address is output. In this embodiment, this specific information is expressed as (FFFF) ₁₆ .

Table 7 is a table that manages CG addresses currently being used for display, and a certain CG address
When SAi is in use, "1" is stored, and when SAi is not in use, "0" is stored. Therefore, when registering a new character pattern in an empty area of the CG memory 3, the address SAi of the table 7 corresponding to the area is set to "1" to indicate that the area is in use.

A register 8 is provided for managing the addresses of the table 7. That is, the register 8 sets the address of the CG memory 3 where a character pattern corresponding to a certain Kanji code is stored. Normally, this register 8 is used when registering one screen worth of character patterns required for display in the CG memory 3.
If table 7 is used up to SAi, the next address SAi+1 is set in register 8.

Character patterns for one screen necessary for display are registered in the CG memory 3, and the necessary character patterns are sequentially read out from the CG memory 3 for display.
However, if new information is to be displayed after all character patterns have been registered in the CG memory 3, the character pattern to be displayed next must be stored in the CG memory 3. In this case, an unnecessary CG address is detected and a new character pattern is stored in the area corresponding to that address. unnecessary
In order to detect the CG address, it is sufficient to search the table 7, and a register 9 is provided for this purpose. In other words, register 9 is the unnecessary CG of table 7.
This register stores an address for detecting an address, and if it is detected in the previous detection process that the unnecessary CG address is SAi, the contents of register 9 are set to SAi+1. Therefore, from next time onwards, detection of unnecessary addresses will start from address SAi+1. Note that when the contents of register 9 reach the final address, they are returned to the starting address SAo.

Next, the operation will be explained with reference to FIGS. 3 to 6. The procedure for loading character patterns between the TCE and the Kanji display device is particularly shown in FIG. 6, so this will be explained first.

TCE regularly issues polling POL to Kanji display devices (terminals). When the terminal detects an unregistered pattern, it issues a CG request to TCE. When TCE detects a CG request in response to POL, it issues a read command (RD) and receives the Kanji code. Character patterns corresponding to all Kanji codes are prepared in advance in the TCE, and from among these character patterns, a character pattern corresponding to the received Kanji code is searched and prepared. Before transmitting the character pattern to the terminal, TCE sends a write command (WT) to the terminal to inform it that the character pattern is to be transmitted to the terminal. The terminal is
The WT sends an ACK to the TCE, informing it that the terminal is ready to receive data. TCE is this ACK
When received, the character pattern is transferred to the terminal, and the terminal issues an ACK to the TCE to notify that it has successfully received the character pattern. Through this procedure, character patterns are transferred from the TCE to the terminal.

Next, the operation of the embodiment shown in FIG. 2 will be explained using FIGS. 3 to 5.

The kanji display device receives display data as a kanji code from the TCE and stores it in an external buffer 1. When the reception is completed, the microprocessor 5 reads the kanji code a from the starting point of the external buffer 1. Next, the corresponding address KAa in table 6 is referred to using the kanji code a as an address.

If the content of KAa is other than (FFFF) ₁₆ , the content SAj is assumed to be the character pattern for kanji code a that has been registered in CG memory 3, and the CG is
SAj is set to address IAo of the internal buffer corresponding to address EAo of external buffer 1.

On the other hand, in Table 6, if the content of KAa is (FFFF) ₁₆ , it is assumed that the character pattern corresponding to kanji code a is not registered in CG memory 3, and the kanji code is transferred to TCE. However, it is necessary to load the corresponding character pattern from TCE. In this case,
The register 8 is checked to find the CG address of the unregistered character pattern. and register 8
When the contents of register 8 do not indicate the final CG address, the value of this register 8 is used as the CG address,
The address corresponding to external buffer 1 is registered in internal buffer 2. After that, update the address of register 8 and external buffer 1 and send it to TCE.
A request is made to load an unregistered character pattern into the CG memory 3. The procedure for loading a character pattern from TCE will be understood from the explanation with reference to FIG. 6 above.

On the other hand, if the contents of the register 8 have been updated to the final address, the CG memory 3 indicates that all character patterns have been registered, so that unnecessary character patterns are detected.

Detection of this unnecessary character pattern is performed as follows. For example, if the display device in this embodiment displays 40 characters x 24 lines = 960 characters on one screen, the CG memory 3 has a memory that can store character patterns for a maximum of 960 characters. Has capacity.
However, the characters actually displayed are these 960 characters.
It is impossible for all characters to be used at the same time; in reality, it is known that at most 10% of them are used. The CG addresses of the character patterns currently used for display are managed by Table 7, so the above-mentioned unnecessary
To detect the CG address, refer to Table 7. Therefore, the microprocessor 15
controls to search table 7 and detect unnecessary CG addresses. That is, the microprocessor 15 sets the value indicated by the register 9 indicating the detection start address of an unnecessary character pattern as an address.
The contents of table 7 are searched and the contents of register 9 are updated until the output value 〓0〓 indicating an unnecessary CG address is obtained. When register 9 is updated to the final CG address, return to the start address SAo and process. continue.

When such table 7 is searched and an unnecessary CG address is detected, the contents of register 9 at that time are
Register it in internal buffer 2 as a CG address.
Then, the addresses of register 9 and external buffer 1 are updated. If an unnecessary address in the CG memory 3 is detected, this indicates that the character pattern is ready to be stored in the area indicated by that address, so a request is made to the TCE to load the unregistered character pattern. The procedure for loading kanji patterns from TCE is as described above. The character pattern transferred from TCE is the searched CG
Stored in the CG area indicated by the address.

Note that when new display data is received by the external buffer 1 from the TCE, the data currently being displayed becomes unnecessary and the entire screen is once erased. At the same time, the contents of table 7 are all set to 0''.
Therefore, when searching the table 7, unnecessary addresses can always be detected.

Although one embodiment of character pattern control has been described above, the present invention can be implemented with various modifications.
For example, although the above embodiment has been described on the premise that the TCE has a memory for storing all character patterns, this memory may be provided within a known central processing unit, or may be provided in a terminal device such as a kanji display device. You can also keep it inside.

As another modification, it is understood that the storage capacity of the CG memory does not necessarily have to be exactly the same as the capacity to store the maximum number of display characters displayed on one screen. In reality, it is impossible for all the character patterns registered in the CG memory to be used simultaneously for one screen display, so if you are trying to achieve this at a low cost, it is necessary to reduce the storage capacity of the CG memory to one screen. It may be a good idea to make it slightly less than the number of characters in minutes. Of course, the storage capacity may be slightly larger than the storage capacity for storing the increased number of characters displayed on one screen.

Note that the present invention is applicable not only to kanji output devices but also to general character output devices.

As described above, according to the present invention, the storage capacity of the CG memory is limited so that character patterns for the maximum number of characters required for displaying one screen are registered, so it is less expensive than the conventional technology, and it is easier to control character patterns. By providing first and second tables for this purpose, character codes or character patterns can be efficiently managed with reference to these tables. Also,
Since the operation of converting character codes into internal CG addresses and the table management are performed by a microprocessor, complicated logic circuits and the like as in the prior art are not required.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating a character pattern control method according to the prior art, FIG. 2 is a block diagram illustrating a character pattern control method according to an embodiment of the present invention, and FIGS. 3 to 5 are operation diagrams. FIG. 6 is an explanatory flowchart showing a procedure for loading character patterns. 1 is external buffer, 2 is internal buffer, 3 is
CG memory, 4 is a table, 15 is a microprocessor, 6 is a table, 7 is a table.

Claims (1)

[Scope of Claims] 1. In a device that sequentially reads and visually outputs character patterns corresponding to a certain character code from a character pattern generator that stores a large number of character patterns, the storage capacity of the character pattern generator is approximately equal to
An external buffer configured to register character patterns for the maximum number of characters to be output in a predetermined range and storing output data as character codes, and an address on the character pattern generator to store the character codes stored in the external buffer. an internal buffer that stores the converted code as an internal code, and a character pattern generator that manages whether or not a character pattern corresponding to the character code is stored in the character pattern generator, and uses the character code as an address. a first table storing addresses on the character pattern generator that can be read; and information managing whether character patterns stored in the character pattern generator are currently provided for output. a second table storing said first table;
When it is detected that the character pattern corresponding to a certain character code is not stored in the character pattern generator based on the presence or absence of an address stored in the table of , in order to search for a character pattern that is not currently provided for output among the character patterns stored in the character pattern generator, and replace it with the character pattern at the address on the character pattern generator corresponding to the searched position. A character pattern control method characterized in that a character pattern corresponding to the character code is loaded into a character pattern generator. 2. In the character pattern control method as set forth in claim 1, a register is provided that holds an address on the character pattern generator where a character pattern to be replaced next is stored, and the contents of the register are the same as the character pattern. A character pattern control method, characterized in that the second table is searched when indicating the last address on the generator.