JP3593818B2 - Non-contact IC card - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technology for data reliability and protection of a contactless IC card.
[0002]
[Prior art]
As an IC card, a non-contact IC card which receives a signal and transmits / receives a signal without a contact terminal by magnetic coupling or capacitive coupling is known. However, in a non-contact IC card, since the state of contact between the card and the reader / writer is not fixed, transmission and reception of data and supply of power may be unstable. Therefore, for example, if the distance between the card and the reader / writer increases while data is being written to the card and power supply is interrupted, data stored in the memory becomes incomplete. As a countermeasure against this, Japanese Patent Laid-Open No. 4-344993 discloses a method in which a memory is divided into two or more blocks and writing is performed alternately in order to cope with data corruption due to interruption during data rewriting.
[0003]
[Problems to be solved by the invention]
In this method, since a plurality of pieces of data of the same part are provided, a memory having a memory capacity twice or more as large as a memory capacity necessary for storing original data is required, and thus costs are increased.
[0004]
[Means for Solving the Problems]
The EEPROM rewrites the memory in block units. Therefore, in the present invention, a plurality of memory blocks are provided as buffer memory blocks for saving data when rewriting data. (A memory area for storing data is called a data memory block), means for designating a buffer memory block, means for checking a memory block, and means for correction are provided.
[0005]
In the buffer memory block, the address of the data memory block is also stored when the data of the data memory block is saved. As a result, when the data memory block to be rewritten is damaged, it can be recovered by the data saved in the alternative block in advance, and the failure of the data area of the card can be corrected at the time of startup.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0007]
FIG. 1 is a configuration diagram of a contactless card. This card has a memory 40 such as an EEPROM that stores data so that data is not lost even when the power is turned off, and is internally divided into a data area 41 and a buffer area 45. The EEPROM rewrites data in the memory in block units, and the buffer area 45 is configured as a plurality of memory blocks in the memory 40 specified by the buffer specifying unit 50. In the buffer area 45, the data in the memory block of the data area 41 to be rewritten is written in the buffer area 45 before the data is rewritten, and the processing is interrupted while the data is being written in the data area 41, and the contents of the data memory block are destroyed. In such a case, the contents of the buffer memory block are returned to the data memory block to prevent the processing from being stopped due to data loss.
[0008]
The memory control unit 30 reads and writes data from and to the memory 40 in accordance with a command from a reader / writer transmitted from the coil 10 using the modulation / demodulation unit 20 or the like. The buffer designating section 50 designates a buffer memory block in which data is to be buffered, and the memory control section 30 reads and writes the buffer memory block based on the designated buffer memory block. The power supply circuit 60 supplies power to the circuit of the IC card by induced electromotive force from the coil 70 due to electromagnetic induction from the outside.
[0009]
FIG. 2 is a configuration diagram of data in a memory block in the data area 41, and FIG. 3 is a configuration diagram of a memory block in the buffer area 45.
[0010]
The data area 41 is configured in units of memory blocks, and includes a data section in which data is stored, a number storage section for storing the number of times of data rewriting, and a check code section for checking a write error. In this embodiment, 410, 411, 412, 413,. . . n.
[0011]
The buffer area 45 is configured in units of memory blocks, and includes a data part in which data is stored, a number storage part storing the number of times of data rewriting of the saved area, and an area number part indicating an address of the saved data area. I have. In the present embodiment, the buffer memory block 451, 452, 453, and 454 constitute the buffer area 45 with four memory blocks.
[0012]
With such a configuration, for each buffer memory block in the buffer 45 area, whether or not a write error has occurred can be determined by checking the saved data memory block indicated by the area number area of the buffer memory block with a check code. If there is an error, the data in the buffer memory block is copied to the corresponding data block, a check code is created and written to the check code area, the number of times of writing is updated, and the data is written to the data memory block. Data loss can be prevented.
[0013]
For example, by looking at the area of the buffer 451, it can be seen that the buffer 451 is used as the data buffer of the memory block 410. Subsequently, the quality of the data in the data section of the memory block 410 can be determined by the code in the check code section. At this time, if the data is correct, the data can be used as it is. If the data is defective, an error code is generated from the data of 451, the number of times of writing is updated, and the data of 451 is written to 410, so that the data before the writing failure Normal data can be restored. On the other hand, when the data in the buffer is abnormal, it can be known from the value of the area number that is not in the normal range. In this case, an error has occurred while writing data to the 451, Since there is no data, there should be no abnormality in the data of 410, and reading of the data area can be processed without any problem.
[0014]
FIGS. 4, 5, 6, 7, and 8 are flowcharts showing the flow of processing of the IC card. The processing flow will be described below with reference to a flowchart.
[0015]
First, in the post-startup processing 800, the area number area is read from the buffer memory block 451 to which the address is notified from the buffer specifying unit 50, and the data in the data memory block in which the data is saved is checked. If the area number is out of the set range of the data memory area, the process proceeds to a subroutine 801. In the subroutine 801, the data in the buffer is initialized in a process 811, and it is determined in a process 812 whether the buffer is correctly initialized. Return to subroutine if initialized properly. If the initialization is not successful, in step 813, a failure in the buffer memory block is transmitted and the process returns.
[0016]
If the process 800 indicates the data memory block in which the area number of the buffer exists, the process proceeds to a subroutine 802.
[0017]
In the subroutine 802, the data area of the data memory block indicated by the area number of the buffer is checked by an error check code in a process 821. If the data area is normal, the process returns from the subroutine. If the error check code is incorrect, a check code is created in step 822 from the contents of the data area of the buffer memory block and the data in the data area, and the number of times of writing is updated to the data memory block indicated by the area of the buffer memory block. In a write operation 823, it is checked whether the data has been normally written in the data memory block. If it is written normally, the program returns from the subroutine. If the data could not be written normally, a message indicating that the data could not be written to the corresponding data memory block was sent in step 824, and the process returns from the subroutine.
[0018]
Hereinafter, in the same manner as the check for the buffer memory block 451 in the process 800, the checks and restoration of the memories are performed on the buffer memory blocks 452, 453, and 454 in the processes 803, 804, and 805, respectively.
[0019]
After the above processing is completed, the fact that the buffer check has been completed is transmitted to the reader / writer in processing 808, and the flow proceeds to processing 806. In the process 806, a command from the reader / writer side is waited, and when a command comes, the process proceeds to a process 087.
[0020]
In the process 807, the process branches to a process corresponding to the command. In the case of reading, the process shifts to process 831 to read and transmit data of the data memory block specified by the command. Thereafter, the flow shifts to step 806 to wait for the next command.
[0021]
In the case of a write command, the contents of the data memory block specified in the command in process 841 are copied to the buffer memory block specified by the buffer specifying unit 50. At this time, a code specifying a data memory block is written instead of the error check code. By looking at this code, it is possible to know which data memory block of the data memory block was saved, and if the contents of the data memory block are damaged, it can be restored. In this embodiment, the specification of the buffer area for saving the contents of the data memory block is performed by the remainder of the sum of the number of times of writing and the area number divided by the number of buffers. This is to prevent the specification of a buffer depending on the data memory block from increasing the number of times of writing in a specific buffer and shortening the rewrite life of the memory block. In step 823, it is determined whether the data has been correctly saved in the buffer memory block. If the data can be saved correctly, in a step 843, the number of write updates is updated, the received data is written to the data memory block, and an error check code is written. Thereafter, the flow shifts to step 806 to wait for the next command.
[0022]
Although the processing 809 is not described this time, it means the existence of a group of subroutines for processing commands other than data read / write. For example, in order to know the life of the card, a memory that determines the number of rewrites or designates a memory as a buffer In the present embodiment, the processing for changing the block is shown as a unit of data for switching the buffer, but the processing is performed for each memory block. You may make it.
[0023]
Further, in the present embodiment, the data to be rewritten is stored in the buffer area in advance. However, even if the data to be written is written in the buffer area in advance and then written in the data area, the data write error similarly occurs. Can respond and improve data reliability.
[0024]
【The invention's effect】
According to the contactless IC card of the present invention, the memory is divided into the data area and the buffer area, and the data to be rewritten is saved in the buffer area of the memory before the data sent from the outside is written into the data area. In addition, even if the written data is defective, the data in the data area can be restored by the data saved in the buffer, so that even if there is more than the writing of the data, the reading of the data is not disabled. Therefore, even when writing defective data or missing data, data can be read and predetermined processing can be performed. Furthermore, since the data area can be rewritten in units of a buffer, the required buffer area can be implemented by securing a sufficiently small area as compared with the data area. A contact IC card device can be provided.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an apparatus.
FIG. 2 is a diagram showing a data configuration of a memory block in a data area.
FIG. 3 is a diagram showing a configuration of a buffer of a memory block in a buffer area.
FIG. 4 is a flowchart showing the operation of the non-contact IC card.
FIG. 5 is a flowchart showing the operation of the non-contact IC card.
FIG. 6 is a flowchart showing the operation of the non-contact IC card.
FIG. 7 is a flowchart showing the operation of the non-contact IC card.
FIG. 8 is a flowchart showing the operation of the non-contact IC card.
FIG. 9 is a flowchart showing the operation of the non-contact IC card.
[Explanation of symbols]
10 data transmission coil 20 data modulation / demodulation unit 30 memory control unit 40 memory 41 data area 45 buffer area 411, 412, 413, 414 data memory block 451, 452, 453, 454 buffer memory block.

Claims (2)

It has transmitting and receiving means for transmitting and receiving signals to and from the outside in a non-contact manner, has means for receiving power of the internal device from the outside in a non-contact manner, a memory for storing data from the outside, and a control means for controlling the memory, At the time of data rewriting, a data area and a buffer area are provided in the memory to cope with failure of rewriting, and a function of writing data sent from the outside to the buffer area and then writing the data to the data area is provided. An IC card device having a function of checking data in a block and, if an abnormality is found, a function of restoring data with data of a substitute block. In claim 1 Symbol placement of cards, contactless IC card system is characterized by providing a function of storing the number of times of rewriting of the storage process.

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