JPH0554158B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a card in which a memory and a microcomputer for controlling the memory are embedded in order to hold various data such as identification, and in particular, as a memory card.
It relates to cards using EEPROM (abbreviation for Electrically Erasable and Programmable Read Only Memory).

BACKGROUND ART Conventionally, data cards that hold data using a magnetic recording method have been mainly used as identification cards (referred to as ID cards) such as identification cards, credit cards, or bank cards.

This magnetic recording type card is advantageous in certain applications, such as when bank cards are used to record deposit balances, as data can be rewritten relatively easily, but data tampering is not sufficiently prevented. However, there are problems in that it is difficult to protect data from magnetic contamination, which is likely to occur when the device is not portable, and that it may not be sufficiently reliable.

Therefore, in consideration of these points, a memory consisting of an integrated circuit (IC) element and a microcomputer (hereinafter referred to as microcomputer) for controlling this memory are embedded in the card, data is stored in this memory, and data is stored as needed. Accordingly, data cards that read out the data and use it for identification, etc., have been proposed and have come into practical use.

In this way, a data card with a built-in IC is
For example, the front view in Figure 1 and the front view in Figure 2 are called cards.
As shown in the cross-sectional view of the figure, a recess 3 is formed in a part of a card base 2 made of a suitable plastic, and an IC module 4 is housed in the recess 3.
This IC module 4 is provided with a contact terminal (electrode) 5, so that an electrical connection can be made between an external circuit and an electronic circuit included in the IC module 4.

Further, the surface of the card base 2 is often provided with a pattern 6 made of predetermined characters or figures drawn with ink or the like, and to protect these, a protective layer 7 made of a suitable transparent plastic or the like is applied. are provided, and together form the IC card 1.

Note that 8 is a striped layer of magnetic material, which is provided so that it can be used as a magnetic recording data card, and is not particularly necessary for an IC card.

The IC module 4 is equipped with various types of memory based on LSI (Large Scale Integrated Circuit) and a microcomputer to control it. An electrical connection with an external data processing circuit is formed via the contact terminal 5, and the memory in the IC card 1 is accessed from the external circuit, allowing data writing and reading, and identification, etc. functions are now being fulfilled.

Conventionally, the configuration of the IC module 4 in such an IC card has been, for example, the third
As shown in the figure, PROM (Programmable Read Only) is used as memory for storing information data.
(memory) is known. This third
In the figure, 40 is a microcomputer, 41 is a PROM, and the microcomputer 40 is a CPU (central
processing unit) 401, ROM (read-only memory) 4 for program storage
02, and RAK which is memory for data calculation
(Random access memory) 403, and each terminal piece 5 ₁ to 5 ₆ of these contact terminals 5
The PROM 40 is connected to an external device through the PROM 40, and data can be written to and read from the PROM 40.

Therefore, this IC card is difficult to tamper with data, has high reliability, is resistant to changes in the magnetic environment, and can easily increase the amount of data that can be stored, so it can be used not only for ID purposes. It has come to be expected that it will have a wide range of uses, including for general data storage.

By the way, as mentioned above, the memory for storing information built into this IC card is PROM.
is often used. And this PROM
In addition to regular non-erasable PROM, which uses a destructive recording method, there are also EPROMs (Erasable and Programmable Read Only), which are read-only memories whose data can be erased by ultraviolet irradiation. memory) and EEPROM, which is a read-only memory that can electrically erase the written data.In either case, the manner in which data is written to it is determined by Known methods include a method in which all data is written at once, and an add-on method in which necessary data is sequentially written at any time while the card is in use.

However, with IC cards, the above
Not only when PROM is used, but even when using the EPROM mentioned above, once information is written there, it cannot be erased, so there is no room for writing information in the memory. When the IC card ran out or the stored information was no longer needed, the card had to be thrown away and a new IC card used.

On the other hand, as a memory that should be built into an IC card,
When an EEPROM is used, the information stored therein can be erased, so the data in the memory can be erased as needed and the IC card can be reused.

By the way, in the field of normal data processing, in order to facilitate handling when storing and updating data and to ensure reliable data management, they are called by names such as page, sector, or record. A method is generally used in which a certain amount of data is managed as one unit.

However, in a normal EEPROM, erasing data written in the memory area is limited to batch erasing of the entire memory area or byte erasing of one byte at a time. With conventional IC cards that use EEPROM, it is not possible to directly erase easily manageable units such as the above-mentioned pages, so in order to do this, it is necessary to specify erase advice in bytes and issue erase commands to the IC card. This method has disadvantages in that data management becomes troublesome because input must be repeated, and deletion processing is complicated and requires a long processing time.

The purpose of the present invention is to eliminate the drawbacks of the prior art described above, and to write and read data in IC cards using byte-erasing EEPROM in units of pages consisting of multiple bytes of memory area. To provide an IC card that can be easily erased.

To achieve this objective, the present invention
A memory area group consisting of multiple bytes of memory area, such as a page unit, is set in the EEPROM memory area, each is assigned an identification code, and this code configures the memory area group to which it is attached. A means for generating addresses for each multi-byte memory area is provided in the IC card, and a predetermined memory area can be erased simply by commanding code data such as a page number, without specifying addresses in byte units. It is characterized by the following points.

Embodiments of the IC card according to the present invention will be described below with reference to the drawings.

The structure of the IC card according to an embodiment of the present invention is the same as the IC card shown in FIGS. 1 and 2,
The built-in IC module 4, as shown in Figure 4, is almost the same as the one in Figure 3.
EEPROM42 is provided instead of PROM41,
The present invention differs from the above-described conventional IC card in that the program stored in the ROM 402 is different from the above-mentioned conventional IC card in that it is configured to execute control operations according to the flowchart shown in FIG.

In the IC card according to the embodiment of the present invention shown in FIG. 4, as shown in FIG. 6, in the memory area M of the built-in EEPROM 42,
A unit representing a set of the appropriate amount of data mentioned above,
For example, n memory areas M ₁ , M ₂ , . . . M _o are set in which data corresponding to a page can be written. Note that since each of these memory areas M ₁ to _{M o} is formed of a memory area for a plurality of bytes, these M ₁ , M ₂ , . . . M _o are hereinafter referred to as a memory area group.

Next, the functions and effects of this IC card will be explained.

This IC card is used for writing data, and each memory area group M ₁ ,
M ₂ ... New data is stored one after another in M _o in page units, and eventually there is no memory area group to store new page unit data, or the page unit data has already been stored. Suppose that the data stored in the memory area group in which the data has been written becomes no longer needed, or that the contents need to be changed or updated.

Then, data erasure processing is performed at this time. First, the IC card is set in a predetermined processing device, and this external processing device issues a data deletion command to the microcomputer 40 in the IC card.
The page number of the data to be erased is input, and the microcomputer 40 starts the process shown in FIG.

When entering the process shown in FIG. 5, the first step is to calculate the address of the first byte in the memory area group M ₁ to _{M o} that corresponds to the page number specified by the external processing device. Ru. At this time, if the memory area groups M ₁ to _{M o} corresponding to each page all have the same number of bytes, the address can be easily determined by calculation, but if they are different, then In this case, it is difficult to determine the above addresses by calculation alone, so in this case, the memory area group M ₁ to M _o corresponding to the page number is
The first address of each of the addresses may be written in advance as address data in a part of the memory area of the ROM 402 or EEPROM 42, and the address may be determined by searching the table.

After completing the processing in this step, proceed to the next step, read data from the EEPROM 42 using the address obtained in the step, check whether any data has been read in the next step, and match it to the specified page number. It is determined whether data to be erased has already been written in the memory area group of the EEPROM 42 that has been erased.

This is currently the available EEPROM
This is because the lifespan of the erase circuit is not so long that it can be practically ignored, and therefore, this is to avoid needlessly shortening the lifespan due to unnecessary erasure processing on the unwritten area, and there is no need for practical consideration. If you can use EEPROM with a reasonably long life, these steps can be omitted.

If the result in this step becomes NO, the processing according to this flow ends here, but if the result in this step becomes YES, then at this time the page number corresponding to the specified page number of the EEPROM 42 will be terminated. Memory area group M ₁ ~ _{M o}
Since some data is stored in one of the pages, we proceed to step 11 and erase each byte belonging to the memory area group corresponding to the specified page number in order from the lowest address. It can be repeated for each byte by making decisions in steps.

If the result in this step is YES, it means that all bytes belonging to the memory area group of the specified page number have been erased, so proceed to step The data is read out, it is confirmed whether the erasure has been completed completely, and the result is judged in steps.

If the result in this step is YES, it means that the data deletion process corresponding to the specified page number has been completed correctly, so the process according to this flow will now be completed. If the result is NO, it means that some kind of error has occurred, so in this case the step is passed, the external processing device is notified of the occurrence of the error, and the process is terminated.

Therefore, according to this embodiment, even when data is to be erased from an IC card, it is possible to process the aggregated data suitable for data management, such as page by page, and the external processing device can issue an erase command and erase the data. Simply enter the desired page number into your IC card, and the EEPROM42 corresponding to the specified page will be displayed.
Erasing processing for each byte belonging to the memory area group is automatically obtained, and necessary data can be erased to prepare for rewriting.

Therefore, in response to the data erase input given in page units, the external processing device inputs the data to the corresponding byte address of the EEPROM 42.
There is no need to convert and specify each byte or perform calculations, greatly simplifying processing and making data management extremely easy.

In the embodiment shown in FIG. 4, an EEPROM 42 that requires a program voltage V _pp is used, but EEPROMs that do not require such a program voltage are also known. If such an EEPROM is applied to the present invention, it becomes unnecessary to supply or control a program voltage by an external processing device, and control processing can be performed more easily.

As explained above, according to the present invention,
In IC cards using EEPROM,
Erasing EEPROM can be easily performed on any set of data, such as page by page, and eliminates the drawbacks of conventional technology.
The controls required for erasing EEPROM data are simple, the time required for processing is short, and data management is easy and systematic.
IC cards can be provided.

[Brief explanation of drawings]

Figure 1 is a front view showing an example of an IC card, Figure 2 is a front view showing an example of an IC card.
The figure is a cross-sectional view taken along line A-A, and Figure 3 is the same.
The block diagram of the IC module, Fig. 4, is a diagram of the present invention.
FIG. 5 is a block diagram showing an embodiment of an IC module in an IC card, FIG. 5 is a flowchart showing an embodiment of data erasing processing by an IC card according to the present invention, and FIG. 6 is a conceptual diagram of a memory area. 1...IC card, 2...card base, 3...
Recess, 4...IC module, 5...Contact terminal,
40...Microcomputer, 42...
EEPROM, 401...CPU, 402...ROM,
403...RAM.

Claims (1)

[Claims] 1 EEPROM, which erases data in predetermined unit memory areas, is a built-in microcomputer used as data storage memory.
In the IC card, a plurality of memory area groups are set in the memory area of the EEPROM, each of which is formed of a plurality of the unit memory areas and each is assigned a predetermined identification code, and the microcomputer is provided with the identification code. The present invention is characterized in that means is provided for generating addresses for each of a plurality of unit memory areas forming the memory area group, and the erase operation can be performed for each predetermined memory area group by designation of the identification code. IC card.