JPH06282702A - Information recording medium with built-in cpu - Google Patents

Abstract

PURPOSE:To provide an IC card which can more efficiently deal with error generation. CONSTITUTION:Inside an EEPROM 15 of the IC card, files A and B and directories (a) and (b) for accessing these files are recorded, and an allocation pointer AP showing an address to record the new file and a directory pointer DP showing an address to record the new directory are recorded. When any error is generated at the DP, the DP is recovered by searching a first non-recorded area by executing a first recovery command (1). When any error is generated at the AP, the AP is recovered based on the contents of the final directory (b) by executing a second recovery command (2). When any error is generated at the directory (a), invalid information is written (3).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium having a built-in CPU, and in particular, a plurality of file recording areas are defined in an EEPROM so that data is classified and recorded for each file and each file is accessed. The present invention relates to an information recording medium that prepares a directory having address information necessary for each file for each file.

[0002]

2. Description of the Related Art IC cards have attracted attention as a new information recording medium replacing magnetic cards. Especially CPU
Since the IC card having a built-in card has a high degree of security, it is expected to be used in various fields. Generally I
C card has 3 such as RAM, ROM, EEPROM
It has built-in types of memory, both of which are accessed by the built-in CPU. The reader / writer device exchanges data with the IC card. When a given command is given from the reader / writer device to the IC card, this command is executed by the CPU in the IC card. For example, in the case of a data write command, the data given to the IC card from the reader / writer device is written in the memory in the IC card, and in the case of a data read command, the data read from the memory in the IC card. Is transferred to the reader / writer device.

The user data to be recorded in the IC card is
Written in EEPROM. Usually EEPROM
A plurality of file recording areas are defined in the file, and data is classified and recorded for each file. In this case, a directory having the address information necessary for accessing each file is created for each file, and this directory is also recorded in the EEPROM. When accessing a specific data file, first, a directory having information necessary for accessing this file is read, and the data file is accessed based on the contents of this directory.

As described above, a plurality of data files and a plurality of directories are written in the EEPROM. For this reason, when additionally writing a new data file and a new directory, it is necessary to sequentially write at a predetermined address. Therefore, normally, an allocation pointer indicating an address at which new file data should be recorded and a directory pointer at an address at which a new directory should be recorded are prepared, and new writing is performed while these pointers are sequentially updated. It manages processing.

[0005]

The above-mentioned allocation pointer and directory pointer play an important role when writing a new data file or directory. If the contents of these pointers are incorrect, an accident will occur in which a new data file or directory is overwritten in the area where the existing data file or directory has been written. However, a portable information recording medium such as an IC card is often used in a rough environment as compared with a general stationary information recording medium, and an error may occur in the contents recorded in the memory. high. Therefore, conventionally, when the error occurs, it is dealt with by a method of recording the contents of the pointer at a plurality of places to provide redundancy. However, in such a method, the more the redundancy increases, the less the memory usage efficiency decreases.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an information recording medium having a built-in CPU capable of more efficiently coping with the occurrence of an error.

[0007]

[Means for Solving the Problems]

(1) At least a RAM, a ROM,
The EEPROM has three built-in memories and a CPU having a function of accessing this memory.
Multiple file recording areas are defined in the file so that the data can be classified and recorded for each file, and a directory with the address information required to access each file is prepared for each file. EE
In the information recording medium recorded in the PROM, a directory pointer indicating an address for recording a new directory is written in a control information area provided in the EEPROM together with a predetermined error check code, and this error check is performed. When the abnormality is recognized by the check using the code and a predetermined recovery command is given from the outside, the directory recording areas in the EEPROM are searched in order from the beginning, and the address of the first unwritten area is set to the correct directory. The writing process is performed as a pointer.

(2) The second invention of the present application is at least RA.
Incorporates three types of memory, M, ROM, and EEPROM, and a CPU having a function of accessing this memory,
A plurality of file recording areas are defined in the EEPROM so that data is classified and recorded for each file, and a directory having address information necessary for accessing each file is prepared for each file. In an information recording medium in which is recorded in the EEPROM, an allocation pointer indicating an address at which new file data should be recorded is written in a control information area provided in the EEPROM together with a predetermined error check code. When the abnormality is recognized by the check using the error check code and a predetermined recovery command is given from the outside, EEPRO
This is a process for rewriting the allocation pointer to a correct one based on the address information described in the final directory recorded in M.

(3) The third invention of the present application is at least RA
Incorporates three types of memory, M, ROM, and EEPROM, and a CPU having a function of accessing this memory,
A plurality of file recording areas are defined in the EEPROM so that data is classified and recorded for each file, and a directory having address information necessary for accessing each file is prepared for each file. Is recorded in the EEPROM, each directory is written together with a predetermined error check code, and an abnormality is recognized by the check using this error check code, and
When a predetermined recovery command is given from the outside,
The process is performed such that the directory in which the abnormality is recognized is rewritten to the directory containing the information indicating that the directory is invalid.

[0010]

[Operation] In the information recording medium according to the present invention, a directory pointer, an allocation pointer, and a directory are recorded together with an error check code, and an abnormality can be recognized when an error occurs by checking using this error check code. . When an abnormality is recognized, it is possible to deal with the error by giving a predetermined recovery command. That is, when a recovery command is given to the directory pointer, the directory recording area in the EEPROM is searched in order from the beginning, and the address of the first unwritten area is recognized as the correct directory pointer, and the error is corrected. Further, when a recovery command is given to the allocation pointer, the error is corrected based on the address information written in the final directory recorded in the EEPROM. Furthermore, when a recovery command is given to the directory in which the error has occurred, information indicating that the directory is invalid is written, and thereafter, access to the data file by the directory can be invalidated.

[0011]

The present invention will be described below based on illustrated embodiments. FIG. 1 is a block diagram showing a state in which a general IC card 10 is connected to a reader / writer device 20. IC
In the card 10, an I / O device 11 for connecting to the reader / writer device 20, a CPU 12, a RAM 13,
The ROM 14 and the EEPROM 15 are built in. The CPU 12 receives an instruction given from the reader / writer device 20 via the I / O device 11 and executes it. Of the three types of memories, the RAM 13 is a volatile memory and is used as a work area for the CPU 12. The ROM 14 and the EEPROM 15 are both non-volatile memories, but the ROM 14 is read-only, whereas the EEPROM can be rewritten at any time. Therefore, a program to be executed by the CPU 12 is prepared in the ROM 14, and user data is recorded in the EEPROM 15 for each file. Figure 2
FIG. 3 is a diagram showing two areas defined in the EEPROM 15. The allocation pointer AP, the directory pointer DP and other control information are written in the control information area 15a, and the user data is written in file units in the file / directory area 15b.

FIG. 3 is a memory map of the EEPROM 15 in the IC card according to the embodiment of the present invention. In the example shown here, in the file / directory area 15b, there are two sets of user data, file A and file B, and two sets of directory a and directory b, which have information necessary to access these files. The directories and have already been written. The directory a has information necessary to access the file A, and the directory b has information necessary to access the file B. Specifically, in each directory, the file name of the corresponding file, the start address, the total data length, information regarding the key required for access, and the like are recorded. As described above, both the data file and the directory are written in the file / directory area 15b. In this embodiment, the data files are sequentially written from the upper end to the bottom of the figure, and the directory With respect to, the writing is performed in order from the lower end to the upper part of the drawing.

On the other hand, an allocation pointer AP and a directory pointer DP are recorded in the control information area 15a. Here, the allocation pointer AP is a pointer indicating an address at which a new file should be recorded, and in the example shown here, indicates an address next to the final address of the file B (the bottommost part of the file B in the figure). .
Therefore, for example, when additionally writing a new data file C, the writing is performed from the address pointed to by the allocation pointer AP toward the lower address in the figure. On the other hand, the directory pointer DP is a pointer indicating the address at which a new directory should be recorded. In the example shown here, the final address of the directory b (the directory b in the figure).
Point to the next address). Therefore,
When additionally writing a new directory c, the writing is performed from the address pointed to by the directory pointer DP toward the upper address in the figure.

As shown in FIG. 3, the directories a and b are recorded with the error check code CRC added. The allocation pointer AP and the directory pointer DP are also recorded with the error check code CRC added. Further, although not shown in the figure, the data in each of the files A and B also has an error check code CRC for each fixed data length.
Is recorded in the state where is added. By checking based on these error check code CRC,
It is possible to recognize whether or not an error has occurred in each recorded content.

The allocation pointer AP and the directory pointer DP play an important role in additionally writing a new data file or directory, and if an error occurs in the contents of these pointers, it causes a serious trouble. . FIG. 4 shows a situation where an error has occurred in the contents of these pointers and the pointers point to the wrong address. In this example, the allocation pointer AP points to an address in the file A, and if additional writing of a new data file C is performed in this state, data will be recorded over the file A. , The contents of file A will be lost. Further, the directory pointer DP points to an address in the file B, and if additional writing of a new directory C is performed in this state, the directory is recorded over the file B. Will be lost.

Therefore, the IC card of this embodiment is provided with a self-diagnosis routine so as to be able to cope with an error in various information recorded in the EEPROM 15. That is, a diagnostic program for performing diagnosis according to the procedure shown in the flowchart of FIG. 5 is described in the ROM 14, and the CPU 12 executes this diagnostic program each time reset is applied. First, in step S1, a CRC check of the allocation pointer AP and the directory pointer DP is performed. That is, the pointers AP and DP are read out from the control information area 15a together with their respective error check codes CRC, and it is recognized whether the error check codes are normal. If an abnormality is found, the process branches from step S2 to step S3,
Set the abnormal status of control information. Then, in step S4, the CRC check of each directory is performed. That is, the file / directory area 15
The directories a and b are read from b together with their respective error check codes CRC to recognize whether the error check codes are normal. If an abnormality is found,
The process branches from step S5 to step S6 to set the abnormal status of the directory. Further, step S7
At, the CRC check of each data file is performed. That is, each file data A and B is read from the file / directory area 15b together with the respective error check code CRC, and it is recognized whether the error check code is normal. If an abnormality is found, the process branches from step S8 to step S9 to set the abnormality status of the data in the file. When the error check is completed in this way, finally in step S10,
Status notification processing is performed. This is a process of notifying the reader / writer device 20 whether or not each abnormal status is set. After all, the status is notified each time the CPU 12 is reset. Specifically, the error message format is displayed on the screen of a display device or the like connected to the reader / writer device 20. The self-diagnosis routine can be executed not only when the CPU 12 is reset, but also by giving a predetermined diagnosis command from the reader / writer device 20.

The feature of the present invention resides in that a recovery command is provided for taking appropriate measures against the error when the occurrence of the error is recognized as a result of such self-diagnosis. In other words, when this recovery command is given from the reader / writer device 20, a recovery processing program for performing the processing described later is prepared in the ROM 14. The IC card of this embodiment includes
There are three types of recovery commands described below.

The first recovery command is a command for recovering the directory pointer DP. As a result of the above self-diagnosis, if an error message indicating that an error has occurred in the directory pointer DP is displayed,
The operator inputs a character string (for example, RECOVERY DP) indicating the first recovery command from the reader / writer device 20. Upon receiving the first recovery command, the CPU 12 performs the following processing. First, as shown by the arrows in FIG. 6, the contents of the data recorded at the respective addresses are sequentially (from the top in the drawing) to the top address (the bottom in the drawing) of the directory recording area in the file / directory area 15b. After reading, the first unwritten area is searched.
When the first unwritten area is found, the address is written in the control information area 15a as the correct value of the directory pointer DP. By this processing, the directory pointer DP is restored.

The judgment as to whether or not the area is an unwritten area can be made, for example, by the following method. That is, at the time of issuing this IC card, the EEPR
All bytes of OM15 are set to "FF".
Then, as the data to be written as the directory or file data, it is decided to use data other than "FF". In this way, the byte in the written area always shows a value other than "FF". Therefore, when the byte having the value of "FF" is first discovered, that is the "first unwritten area". More preferably, when the byte with the value of "FF" is found first, the search is advanced for several bytes beyond that, and it is confirmed whether or not the byte has the value of "FF". Good to do. By making such a confirmation, even if it happens that only one byte is changed to "FF", the unwritten area can be surely recognized.

The second recovery command is a command for recovering the allocation pointer AP. As a result of the self-diagnosis described above, when an error message indicating that an error has occurred in the allocation pointer AP is displayed, the operator sends a character string (for example, RECOVERY AP) indicating the second recovery command to the reader / writer device 2.
Enter from 0. Upon receiving the second recovery command, the CPU 12 performs the following processing. First,
The final directory (directory b in the example of FIG. 6) recorded in the directory recording area in the file / directory area 15b is read. Then, the start address and the total data length L of the file B recorded in the directory b are read, and based on the sum of these,
The address next to the final address of the file B (address indicated by the arrow in FIG. 6) is obtained, and this address is set as the correct value of the allocation pointer AP, and the control information area 1
Write in 5a. By this processing, the allocation pointer DP is restored.

The third recovery command is a command for dealing with a case where an error occurs in a specific directory. As a result of the self-diagnosis described above, for example, when an error message indicating that an error has occurred in the directory a is displayed, the operator uses a character string () that indicates that the third recovery command is executed for the directory a. For example, RECOVERY DIR: a) is input from the reader / writer device 20. Upon receiving the third recovery command, the CPU 12 performs the following processing. That is, as shown by the arrow in FIG. 6, invalid information is written in the directory a recorded in the file / directory area 15b. This invalid information is, for example, "if the value of the n-th byte of the directory is" 00 ", the directory is invalid", and the invalid information is "n-th byte of the directory a". All that is necessary is to write "00". After that, the directory a will be treated as invalid. This third recovery command does not have a function of recovering an error. Therefore, as in the above example, when an error occurs in the directory a, the file A can no longer be accessed. However, by invalidating the directory a, it is possible to prevent erroneous file access using the wrong directory.

Although three types of recovery commands have been described above, the feature of the present invention resides in that the input of these recovery commands causes the IC card to take measures against the error. In other words, even if a message notifying that an error has occurred appears on the screen of the display device connected to the reader / writer device 20, unless the operator inputs a recovery command for the message, the CPU 12 It does not process the error. Of course, if an error is recognized by executing the self-diagnosis routine shown in FIG. 5, it is possible to program the processing for this error automatically without waiting for the input of the recovery command from the reader / writer device 20. it can. However, generally, the main cause of destroying the data in the EEPROM incorporated in the IC card is the disturbance such as electromagnetic noise. Therefore, in an environment where such noise still remains, it is dangerous to automatically perform error recovery processing. In the present invention, an error recovery process is first executed by inputting a recovery command. The operator may confirm the environment where no disturbance such as noise exists and then input the recovery command.

The present invention has been described above based on the illustrated embodiment, but the present invention is not limited to this embodiment and can be implemented in various modes other than this. For example, the above-described embodiment is an example in which the present invention is applied to an IC card, but the present invention can be widely applied to an information recording medium having a built-in CPU.

[0024]

As described above, according to the information recording medium of the present invention, when an error occurs in the data in the built-in EEPROM, a predetermined recovery command can be input to execute the process for the error. As a result, it becomes possible to deal with the error occurrence more efficiently. For example, it is not preferable to automatically perform recovery inside the card immediately after the accident because the disturbance causing the accident may still remain. According to the present invention, it is possible to input a recovery command after a certain amount of time from the occurrence of an accident in anticipation of the time when the disturbance is reduced, and it is highly possible to realize error processing that is not affected by the disturbance. .

[Brief description of drawings]

FIG. 1 illustrates a general IC card 10 and a reader / writer device 2
It is a block diagram which shows the state connected to 0.

FIG. 2 is an EEP incorporated in the IC card 10 shown in FIG.
It is a figure which shows the area | region defined in ROM15.

FIG. 3 is an E of an IC card according to an embodiment of the present invention.
3 is a memory map of EPROM 15.

4 is a diagram showing a state where an error occurs in an allocation pointer AP and a directory pointer DP in the EEPROM 15 shown in FIG.

FIG. 5 is a flowchart showing a processing procedure of a self-diagnosis routine prepared in the IC card according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating recovery processing by three types of recovery commands performed for the error shown in FIG.

[Explanation of symbols]

 10 ... IC card 11 ... I / O device 12 ... CPU 13 ... RAM 14 ... ROM 15 ... EEPROM 15a ... Control information area 15b ... File / directory area 20 ... Reader / writer device

Claims (3)

[Claims] 1. At least RAM, ROM, EEPRO
Incorporating three types of memory M, and a CPU having a function of accessing this memory, a plurality of file recording areas are defined in the EEPROM so that data is classified and recorded for each file. A directory having address information required to access each file is prepared for each file, and this directory is used as the EEP.
In the information recording medium recorded in the ROM, a directory pointer indicating an address for recording a new directory is written in a control information area provided in the EEPROM together with a predetermined error check code, and the error is recorded. When the abnormality is recognized by the check using the check code and a predetermined recovery command is given from the outside, the directory recording area in the EEPROM is searched in order from the beginning, and the address of the first unwritten area is searched. An information recording medium having a built-in CPU, which is characterized by performing a writing process as a correct directory pointer. 2. At least RAM, ROM, EEPRO
Incorporating three types of memory M, and a CPU having a function of accessing this memory, a plurality of file recording areas are defined in the EEPROM so that data is classified and recorded for each file. A directory having address information required to access each file is prepared for each file, and this directory is used as the EEP.
In an information recording medium adapted to be recorded in a ROM, an allocation pointer indicating an address at which new file data should be recorded is written in a control information area provided in the EEPROM together with a predetermined error check code, When an abnormality is recognized by the check using the error check code and a predetermined recovery command is given from the outside, the allocation pointer is based on the address information described in the final directory recorded in the EEPROM. An information recording medium having a built-in CPU, which is characterized by performing the process of rewriting 3. At least RAM, ROM, EEPRO
Incorporating three types of memory M, and a CPU having a function of accessing this memory, a plurality of file recording areas are defined in the EEPROM so that data is classified and recorded for each file. A directory having address information required to access each file is prepared for each file, and this directory is used as the EEP.
In the information recording medium recorded in the ROM, each directory is written together with a predetermined error check code, an abnormality is recognized by the check using this error check code, and a predetermined recovery command is given from the outside. An information recording medium having a built-in CPU, which performs a process of rewriting a directory in which an abnormality is recognized to a directory containing information indicating that the directory is invalid when the information is recorded.