JPS607293B2 - How to create a code table - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has an efficient configuration of code conversion tables for the interface code system and the internal code system, and utilizes the empty area of random access memory (RAM) to store data in fixed memory (ROM).
) The present invention relates to a method for creating a code table for code conversion that reduces the capacity of the code table.

Conventionally, devices have been widely used that convert input character codes through a standard interface code system into an internal code system, generate a corresponding character pattern, and operate a printer or the like.

In this case, the codes used for devices for each country differ depending on the country, and the character patterns corresponding to the different codes are different. Therefore, as shown in Fig. 1, for example, RO
8-bit standard interface code tables IA, IB, and IC for countries A, B, and C and corresponding 8-bit internal code tables 2A, 2B, and 2C are provided in M. In this configuration, the standard interface code tables IA, IB, and IC are, for example, the same 8-bit code system in each country, but the contents, that is, the areas used and the characters used are different. On the other hand, internal code tables 2A, 2B, and 2C contain all the codes that can be processed by the device, and the same table is the standard interface code table IA.
, IB, and IC, and one pair is used for each country. In such a case, the division is clear, but the ROM capacity is enormous and the utilization rate is poor.
On the other hand, in recent years, the mass production of large-capacity RAM chips has progressed, and the price of a large-capacity unit may be cheaper than that of a required-capacity one.

Therefore, large-capacity devices are increasingly being used instead of the required capacity.

For example, even if a large byte is required, a chip of one thigh is used to form one byte. The inventor of the present invention has considered reducing the ROM capacity for storing the code conversion table by effectively utilizing the empty area generated in this case.

An object of the present invention is to provide a code conversion code table creation method that efficiently configures the code conversion tables for the interface system and the internal code system, and reduces the capacity of the ROM by using the free area of the RAM. be.

In order to achieve the above object, the code table creation method of the present invention operates on two types of code systems, an interface code system and an internal code system, and processes an input interface code by converting the internal code as well.
The device has a fixed memory (ROM) in which a set of internal code tables serving as a reference and a plurality of internal codes corresponding to specific codes among the interface code system are stored; A set of internal code tables stored in the fixed memory is transferred to a random access memory (
RAM), one of the plurality of internal codes is selected based on the code system designated by the code system designation means, and the corresponding code is selected from the internal code table developed in the RAM. It is characterized by replacing it with internal code.

The principle and embodiments of the present invention will be explained in detail below.

FIGS. 2a to 2c are diagrams explaining the principle of the present invention. In the present invention, the ROM stores only an internal code table 3 as a reference shown in FIG. Among these, country conversion table 4 is the standard internal code table A and B, as shown in Figure b.
, corresponds to country-specific interface codes 4-1 such as country C,
This is a table for converting internal codes 4-2 for countries A, B, and C. By specifying the country of use in the country specification register that specifies the country, and using the standard internal code table 3 and country conversion table 4 in the ROM, and roughly combining them, the same figure can be stored in the empty area of the RAM mentioned above. Country-specific internal code table 5 shown in c, that is, a table for converting the country-specific interface code to that country's internal code, and interface code table 6, that is, the code in which undefined codes are defined for each country. Expand both tables that store information indicating , and use them for code conversion. The standard internal code table 3 in the ROM is, for example, 8.
It is stored in a 25-bit area, and the country conversion table 4 is the number of codes that require conversion for each country multiplied by the national religion, so for example, if the number of codes is 10 bytes and the number of countries is 4. Then it is only about 40 bytes, so the total is 29
6 bits, which is 256 bits per country in the conventional example shown in Figure 1.
× 2 bytes, compared to 2048 gui in 4 countries, RO
M capacity can be significantly reduced.

The RAM stores 256 x 2 bytes for the internal code table of the country of use and the interface code table, but because this uses empty space for the reason mentioned above, it is not a substantial expansion and is instead used. improve the rate.
FIG. 3 is an explanatory diagram of the configuration of the present invention for realizing the above method, and FIGS. 4a to 4c are flowcharts showing the operation of FIG. 3.

In FIG. 3, microprocessor (MPU) 1 1
A ROM 12 that stores a conversion program for creating an external code table for the standard internal code table 3 and the country-specific conversion table 4, and the country-specific internal code table 5 and interface code table 6 are expanded and written to the data bus 7. RAM 13 is connected.

Further, a country specification register 15 is provided, and each country is coded and specified as described later, and the code in the country conversion table 4 in the ROM 12 is selected. Based on the contents of the standard internal code table 3 and the selected country conversion table 4, a country internal code table 5 and an interface code table 6 in the RAM 13 are created. When the input character code of the country of use is input via the interface 14, the code is converted by both tables 5 and 6 in the RAM 13, and the character code corresponding to a predetermined character pattern is sent to the printer 6.

FIG. 4a shows the procedure for creating a code table.

First, the MPU II converts the reference internal code table 3 in the ROM 12 to the RAM 1 according to the conversion program in the ROM 12.
3 and store it. Next, the country specification register 15 shown in FIG. Next, as shown in FIG.
For a specific memory address XXYZ in the address area of 25 bits (XX00 to XXFF) of By converting, a country-specific internal code table 5 can be created. In addition, each country code usually includes a number of unique invalid codes, that is, undefined codes.

Therefore, invalid codes in the country-specific internal code table 5 are determined, and invalid codes of the corresponding interface code system are imported and converted to create an interface code table 6, and the process ends. In this way, using the country-specific internal code table 5 created in the RAM 13 and the corresponding interface code table 6, code conversion can be performed for the input character code of the country of use, and a predetermined character pattern can be printed. As explained above, according to the present invention, only the reference internal code table and the country conversion table are stored in the ROM, the country of use is specified by means for specifying the country, and both tables in the ROM are used. A national internal code table and an interface code table for the country of use are created in an empty area in the RAM, and these are used to convert the input character code of the country of use.

As a result, the ROM only needs to have an area for one type of standard internal code table and some country-specific conversion tables.
The capacity of OM can be significantly reduced. Instead, it is necessary to provide a country-specific internal code table and an interface code table for each country of use in the RAM, but since this uses empty space, it is not a substantial addition. Therefore, a highly usable and inexpensive method for creating code tables for each country can be obtained. Although the above explanation has been made for each country, it can also be applied to conversion table creation methods for kana code systems and kana code system systems used in Japan, for example.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional example, FIGS. 2 a to c are explanatory diagrams of the principle of the present invention, and FIG. 3 is an explanatory diagram showing the configuration of an embodiment of the present invention.
4a to 4c are explanatory diagrams showing the operation of the embodiment of FIG. 3, in which 3 is a standard internal code table, 4 is a country conversion table, 5 is a country internal code table, and 6 is a Interface code table, 7 is data bus, 1 1 is MPU
, 12 is a ROM, 13 is a RAM, 14 is an interface, 15 is a country designation register, and 16 is a printer. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a device that operates with two types of code systems, an interface code system and an internal code system, and converts input interface codes into internal codes for processing,
The device has a fixed memory (ROM) in which a set of reference internal code tables and a plurality of internal codes for specific codes among the interface code system are stored. 1 stored in memory
The set of internal code tables are stored in random access memory (R
AM) and one of the plurality of internal codes based on the code system designated by the code system designation means.
A method for creating a code table, comprising: selecting one of the internal codes, and replacing a corresponding code in an internal code table developed in a RAM with the selected internal code.