JPH1139450A - IC card - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To realize a ring buffer that can be accessed at high speed in an IC card. SOLUTION: The following column read command is prepared. When a column read command is issued from the reader / writer, the first page of the buffer area to be read specified by the command is set in the PA register in the IC card. Next, an address for reading, for example, 1-byte data at a predetermined position of the page indicated by the PA register from the memory (EEPROM) in the IC card is generated, and the data is read using the generated address. When such a read operation is repeated while incrementing the value of the PA register and reading is performed up to the last page of the buffer area, all the read data is transmitted to the reader / writer. The reader / writer reads out the status information of all pages of the ring buffer at once by this column read command, detects the latest write page, and reads / writes the ring buffer based on the page.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an IC card for exchanging data with a data reading / writing device.

[0002]

2. Description of the Related Art An IC card exchanges data with a data reading / writing device, and can be used for various transactions, for example. In this case, history information of transactions and the like is often stored in an IC card. In the process of storing such history information in the IC card, if the storage area prepared in the memory of the IC card as the area for storing the history information becomes full, the oldest data in the storage area is erased. Then, the latest data is written in the erased area. Therefore, when history information such as transactions is stored in the IC card, it is necessary to realize a ring buffer in the IC card.

In an IC card, an EEPROM (Electrically Eras) is usually used as a memory for storing data.
A programmable programmable read only memory (electrically erasable and writable ROM) is used. EEPROM is
Writing takes time, and writing is often performed in units of a predetermined size called a page (for example, 16 bytes). On the other hand, the data unit viewed from the application of the IC card is called a file, and the file size is usually set to be equal to the page size in many cases. When a ring buffer is realized in such an IC card to store transaction history information, FIG.
As shown in (1), history information 1, history information 2,..., History information n are written in order from the first page 1 into a predetermined area composed of a plurality of pages prepared as a ring buffer area in the memory of the IC card. Is going on. Then, when a write request is further generated after writing to the last page n is performed, the latest history information n + is added to the first page 1 where the oldest history information 1 is written.
1 is overwritten (see FIGS. 15B and 15C).

In realizing a ring buffer, usually,
A read pointer indicating a position to be read in the ring buffer and a write pointer indicating a position to be written are prepared. When storing history information such as a transaction in an IC card, the read pointer indicates a page that has been written most recently. It has become. Therefore, the write point always points to the page next to the read pointer. As a result, in both reading and writing with respect to the ring buffer, substantially, only a pointer (hereinafter, referred to as a “latest write pointer”) that points to a page (latest write page) in which history information is written most recently may be obtained. Will be.

As described above, when a data reading / writing device (hereinafter referred to as a "reader / writer") reads or writes history information for an IC card having a built-in memory that uses a predetermined area as a ring buffer. It is necessary to obtain the value of the latest write pointer in the ring buffer after the power supply to the IC card is started. In contrast,
In a conventional IC card in which a ring buffer is realized, the contents of each page constituting the ring buffer are checked to find the latest write page (hereinafter, an IC card employing this method is referred to as "conventional example 1"). Alternatively, an area for storing the latest write pointer is separately provided in a memory (a non-volatile memory such as an EEPROM) of the IC card (hereinafter, an IC card employing this method is referred to as “conventional example 2”). The IC card has a CPU (Central Processing Uniform).
t) Some have a built-in (central processing unit) etc. and have an information processing function, while others have only a read / write function. In the case of an IC card having an information processing function, history information is obtained from an external reader / writer. When reading or writing data, the contents of each page constituting the ring buffer are searched inside the IC card to search for the latest write page, or the latest write pointer storage area (hereinafter referred to as “pointer area”). The value of the latest write pointer has been obtained by reading the value stored in the On the other hand, in the case of an IC card having only a read / write function, an external reader / writer reads data in the area of the ring buffer from the IC card and searches for the latest write page, or from a pointer area in the IC card. The value of the latest write pointer has been obtained by reading the latest write pointer.

[0006]

A conventional IC card is:
If data can be read or written only in page units (for example, 16 bytes in a horizontal row) and an area for the latest write pointer is not provided in the memory, a ring is searched for the latest write page. All data in the storage area allocated to the buffer had to be read in page units. As a result, it took a lot of time to access the ring buffer.

On the other hand, when the pointer area is provided in the memory, every time the history information is written, it is necessary to perform writing to the pointer area in order to update the latest write pointer. Memory (usually,
Since it is provided in an EEPROM, it takes time to write the data. As a result, it took a long time to write the history information. When a pointer area is provided in an EEPROM or the like, deterioration of the EEPROM due to a large number of rewrites of the pointer area also poses a problem. Accordingly, an object of the present invention is to provide an IC card that realizes a ring buffer that can be accessed at high speed without providing a pointer area in a nonvolatile memory.

[0008]

According to a first aspect of the present invention, there is provided a first IC card for receiving a command from a data read / write device, and executing the data read / write based on the received command. In an IC card for exchanging data with a writing device, receiving means for receiving data including a command from the data reading / writing device, transmitting means for sending data to the data reading / writing device, A storage area configured by collecting a plurality of pages including a data area for storing data received from the data read / write device and a status area for storing status information indicating writing to the data area. A storage unit having a storage area used as a ring buffer, and storing data received from the data reading / writing device. Writing control means for writing status information indicating the writing to a status area of a page including the data area where the data has been written, and receiving means as data from the data reading / writing device When a predetermined command is received, status information stored in the status area is sequentially read for all pages in the storage area, and the read status information is transmitted to the data reading / writing device by the transmission means. And, it is characterized by having.

A second IC card according to the present invention is an IC card for receiving a command from a data reading / writing device and transmitting / receiving data to / from the data reading / writing device based on the received command. Data read /
Receiving means for receiving data including a command from a writing device; transmitting means for sending data to the data reading / writing device; a data area for storing data received from the data reading / writing device; A storage unit having a storage area configured by collecting a plurality of pages including a status area for storing status information indicating writing to the area and being used as a ring buffer; and configuring the storage area. The status information of all pages to be written is initialized to the same value in advance, and when data received from the data read / write device is written to the data area, the page including the data area to which the data is written is written. Write control means for inverting the value of a bit constituting status information of each page, and the status of each page in the storage area. Status information is sequentially read out, and when the value of the status information read out is different from the value of the status information read out immediately before, the page in which the status information read out immediately before was stored was written to the data area latest. If the value of the read status information is the same as the latest write page and the value of the read status information is the same over all pages in the storage area, the page in which the status information read last is stored is the latest write page, and Ring buffer control means for controlling the reading and writing of data from and to the storage area used as a ring buffer based on the above.

A third IC card according to the present invention is characterized in that, in the second IC card, the status information comprises one bit.

In a fourth IC card according to the present invention, in the second IC card, the status information is composed of an odd number of bits, and the writing control means is configured to control the odd number of bits constituting the status information. Initializing the bit values so that they are all the same, the ring buffer control means:
Detecting the latest written page by generating status information that does not include a bit having a different value by a majority operation on the read status information and using the status information generated by the majority operation in place of the read status information. It is characterized by.

A fifth IC card according to the present invention is an IC card which receives a command from a data reading / writing device and transmits / receives data to / from the data reading / writing device based on the received command. Data read /
Receiving means for receiving data including a command from the writing device; transmitting means for sending data to the data reading / writing device; and a page including an area for storing the data received from the data reading / writing device. A storage unit having a storage area configured as a plurality of storage areas and used as a ring buffer; and a value of a page indicating a read position or a write position for using the storage area as a ring buffer. And ring buffer control means for detecting after the power supply to the card is started and before receiving a command from the data read / write device.

A sixth IC card according to the present invention is the IC card according to any one of the second to fourth IC cards, wherein the ring buffer control means comprises: Before receiving a command from the data read / write device, the latest write page is detected.

In a seventh IC card according to the present invention, in the second IC card, the size of the status area of each page in the storage area is an integer byte, and the status information is stored in the status area. A write confirmation data area is provided as an area other than an area used, and the write control means writes the data received from the data read / write device when writing the data in the data area. Invert the values of the bits constituting the status information of the page including the data area, and check whether or not the data has been correctly written to the data area in the write confirmation data area in the status area of the page. For writing data to be performed.

In an eighth IC card according to the present invention, in the above-mentioned seventh IC card, the ring buffer control means includes: i) detecting a latest write page by reading status information of each page in the storage area; Determining means for reading the write confirmation data of the latest write page and determining whether data has been correctly written in the data area of the latest write page based on the write confirmation data. And ii) a latest write page changing means for renewing a page immediately before the latest write page as a latest write page when it is determined that data is not correctly written in the data area of the latest write page. And is characterized by including.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Embodiment 1 FIG. <1.1 Hardware Configuration> FIG. 1 is a block diagram showing a schematic configuration of an IC card according to the first embodiment of the present invention. The IC card 100 is a non-contact type IC card that transmits and receives data to and from a reader / writer 200 by radio waves, and includes an antenna 10, a modulation / demodulation circuit 12, an input / output circuit 14, a control circuit 16, The input / output circuit 14, the control circuit 16, and the memory 18 are connected by a bus 20. In addition, IC card 100
Is provided with a power supply circuit (not shown) for supplying power to the above-described units.

In the IC card 100 having the above configuration, the antenna 10, the modulation / demodulation circuit 12, and the input / output circuit 14
In addition to functioning as a receiving unit for receiving data including a command from the reader / writer 200, it functions as a transmitting unit for transferring data from the IC card 100 to the reader / writer 200. The memory 18 is a non-volatile storage unit composed of an EEPROM, and stores data and the like received from the reader / writer 200. The control circuit 16 is configured using a CPU and a memory for storing a predetermined program and the like, and controls operations of the input / output circuit 14 and the memory 18 and the like by the CPU executing the program.

The reader / writer 200 that exchanges data with the IC card 100 constantly transmits radio waves.
The IC card 100 can operate within a predetermined range in which radio waves from the reader / writer 200 can be received (this predetermined range is called an “operation area”).

When the IC card 100 enters the operation area, the radio wave from the reader / writer 200 is received by the antenna 10 and converted into an electric signal, and the electric signal is transmitted to the modulation / demodulation circuit 12 and the power supply circuit (not shown). Supply. The power supply circuit supplies power by rectifying the electric signal and supplying it to each unit. The reader / writer 200 is an IC
When data is not transmitted to the card 100, an unmodulated radio wave is transmitted. When data is transmitted, a radio wave in which the data is modulated and included in a carrier is transmitted.

<1.2 Outline of Operation> Reader / Writer 20
When data is transmitted from 0 to the IC card 100, the modulation and demodulation circuit 12 extracts the data by demodulating the electric signal supplied from the antenna 10 and inputs the data to the input / output circuit 14 as serial data. The input / output circuit 14 converts serial data input from the modulation / demodulation circuit 12 into parallel data and outputs the parallel data to the bus 20. The control circuit 16
It operates according to commands included in the data received from the reader / writer 200, and controls the input / output circuit 14 and the memory 18.

By such an operation, the IC card 100
Receives the data from the reader / writer 200 and stores it in the memory 18, and sends the data stored in the memory 18 to the reader / writer 200. Memory 1 as described above
Reference numeral 8 denotes an EEPROM, and writing is performed in page units. In the present embodiment, one page corresponds to one page.
6 bytes. In accordance with this, reader / writer 200
Reading and writing of data from and to the memory 18 in the IC card 100 are performed in page units.

That is, a command requesting data writing from the reader / writer 200 (hereinafter, a “write command”)
Is received, the control circuit 16 writes one page of data (16-byte data) sent together with the write command into the memory 18 in accordance with the write command. The page address indicating the writing position to the memory 18 at this time is specified by the write command.

On the other hand, when a command requesting data reading (hereinafter referred to as a “read command”) is received from the reader / writer 200, the control circuit 16 transmits a desired page of data from the memory 18 in accordance with the read command. read out. The page address indicating the read position from the memory 18 at this time is specified by the read command. The control circuit 16 transmits the read data to the bus 2
The input / output circuit 14 transfers the parallel data to the input / output circuit 14 as serial data. The modulation and demodulation circuit 12 generates a signal in which the serial data is modulated and included in a carrier wave, and the antenna 10 transmits the signal as a radio wave.

<1.3 Realization of Ring Buffer> In order to use the above-described IC card 100 for various transactions and to store history information of transactions and the like in the IC card 100,
As described above, it is necessary to realize a ring buffer (see FIG. 15). For this reason, in the present embodiment, a storage area consisting of a plurality of continuous pages in the memory 18 is secured as a buffer area, and this buffer area is used to store data to be read and written with the reader / writer 200 in page units. It is an area for storing. As shown in FIG. 2, each page in the buffer area includes a data area a2 for storing history information, and a status area a1 for storing status information indicating writing of history information to the data area a2. Then, the page address which is the value of the page on which the latest writing was performed (the latest writing page) is used as a read pointer, and the page next to the latest writing page is used as a write pointer (where the latest writing page is the buffer area). If it is the last page, the first page address of the buffer area is used as a write pointer), and writing and reading to and from the buffer area are performed. As a result, the buffer area is used as a ring buffer.

More specifically, when the reader / writer 200 designates a read pointer as a read page address in a read command and designates a write pointer as a write page address in a write command, the buffer area is used as a ring buffer. . However, for this purpose, it is necessary for the reader / writer 200 to detect the latest write page in the buffer area before issuing a read command or a write command, and obtain a read pointer and a write pointer based on this. Therefore, in the present embodiment, a column read command is prepared to read out status information indicating writing to each page in the buffer area at once.
The column read command mentioned here means that data (for example, the value of the first byte) at a predetermined position of each page in a storage area of a predetermined range specified by the command is read from the IC card 100 by issuing a single command. The command to request. That is, the conventional read command can read only 16 bytes (one page) of data in the "horizontal direction", but according to the column read command, a predetermined position in a plurality of continuous pages (for example, The data of the (first byte) can be read in the “vertical direction (column direction)”.

<1.4 Command Execution Processing> As described above, the operation of the IC card 100 of the present embodiment in which a column read command is prepared in addition to a write command and a read command will be described with reference to a flowchart shown in FIG. I will explain it. In the present embodiment, in the column read command, the buffer area to be subjected to the column read is specified by the page value, and the position of the read target in each page in the buffer area (for example, 1 of each page)
Byte) is specified. It is also assumed that the value of the page to be written (for example, a write pointer) is specified in the write command, and the value of the page to be read (for example, the read pointer) is specified in the read command.

When the IC card 100 enters the operation area and receives radio waves from the reader / writer 200, the IC card 10
When the power supply to each unit of “0” is started, first, an initial setting is performed (step S10), and thereby the IC card 100 is ready to receive a command from the reader / writer 200. After the initial setting, the system waits for a command to be sent from the reader / writer 200 (step S12). When the command is issued from the reader / writer 200 and transmitted as a radio wave, the IC card 100 Is received by the antenna 10 and transferred to the control circuit 16 via the modulation / demodulation circuit 12 and the input / output circuit 14. The control circuit 16 interprets the command (step S14), and executes a column read command execution process (step S1) according to the type of the command.
6), one of the write command execution processing (S18) and the read command execution processing (Step S20).

<1.4.1 Column Read Command> FIG.
9 is a flowchart showing a procedure of a column read command execution process (step S16 in FIG. 3). When recognizing the column read command, the control circuit 16 first sets the value of the first page of the buffer area specified by the column read command in a predetermined register (hereinafter, referred to as a “PA register”) provided in the control circuit 16. (Step S
100), by using the value of the PA register, an address (hereinafter referred to as a “column address”) for accessing a read target position designated by a column read command in the first page of the buffer area is generated (step S1).
02). For example, when the status area a1 is the first byte of each page and it is desired to read the status information of each page, the address of the first byte of the page indicated by the PA register is generated as a column address. When the column address is generated, the data of the read target position of the first page (hereinafter referred to as “column read data”) is read from the memory 18 using the generated column address, and the read column read data is temporarily stored in the control circuit 16. It is stored (step S104). Next, it is determined whether the value of the PA register is the last page value of the buffer area specified by the column read command, that is, whether or not the column read data of the last page of the buffer area has been read (step S106). ). If the value of the PA register is not the last page value of the buffer area, the value of the PA register is incremented by 1 (step S108), and the process returns to step S102.

Thereafter, in the same manner, steps S102 → S
By repeatedly executing 104 → S106 → S108, the column read data of each page in the buffer area designated by the column read command is sequentially read and stored in the control circuit 16. During this time, step S106
If it is determined that the value of the PA register is the last page value of the buffer area, that is, if it is determined that the column read data of the last page has been read, the process proceeds to step S110. At this point, column read data of all pages in the buffer area, that is, data obtained by reading the buffer area in the column direction is stored in the control circuit 16. At step S22, these data are stored in a column read command. Is transferred to the input / output circuit 14 for transmission to the reader / writer 200 as a response to the command, thereby ending the processing of the control circuit 16 for the column read command. When the entire buffer area used as the ring buffer is specified by the column read command, and the position (for example, the first byte) of the status area a1 is specified as the read target position, the status information of each page constituting the ring buffer is obtained by the above processing. Is obtained.

The response transferred to the input / output circuit 14 is transmitted to the reader / writer 200 as a radio wave via the modulation / demodulation circuit 12 and the antenna 10.

<1.4.2 Write Command> FIG. 5 is a flowchart showing a procedure of a write command execution process (step S18 in FIG. 3) for writing history information in the ring buffer. In this case, the write command
A write pointer to the ring buffer is specified as a page to be written, and history information is sent from the reader / writer 200 as write data together with a write command. When recognizing the write command, the control circuit 16 first sets a write pointer, which is a page value specified by the write command, in a PA register provided in the control circuit 16 (step S120), and stores the value of the PA register in the PA register. Then, an address for writing to the memory 18 is generated (step S122). Using this address, the history information sent from the reader / writer 200 together with the write command is written to the ring buffer in the memory 18 (step S124). At this time, the status information in the page specified by the PA register, that is, the page indicated by the write pointer is also updated by the writing. After that, a response to the write command is transmitted to the reader / writer 200 (step S
126). Thus, the execution of the write command ends.

<1.4.3 Read Command> FIG. 6 is a flowchart showing the procedure of a read command execution process (step S20 in FIG. 3) for reading history information from the ring buffer. In this case, a read pointer to the ring buffer is specified as a page to be read in the read command. When recognizing the read command, the control circuit 16 first sets a read pointer, which is a page value specified by the read command, in a PA register provided in the control circuit 16 (step S13).
0), an address for reading data from the memory 18 is generated using the value of the PA register (step S132). Next, using this address, the memory 18
The history information is read from the ring buffer in (step S134). Then, the read history information is transmitted to the reader / writer 200 (step S136).
Thus, the execution of the read command ends.

<1.5 Other Configurations of Control Circuit> The control circuit 16 of the present embodiment for performing the above-described operation is constituted by a CPU and a memory for storing a predetermined program and the like.
When the PU executes the program, a control operation for the memory 18 and the input / output circuit 14 including the above-described operation for the column read command is realized. However, as can be seen from the above description, the functions to be realized by the control circuit 16 are to interpret a command issued from the reader / writer 200 and generate an address for accessing the memory 16 in accordance with the command, It is to generate a control signal for causing the memory 16 and the input / output circuit 14 to perform a desired operation, and these functions can be easily realized by hardware. Therefore, by comparing the cost and power consumption of the currently available CPU chip with the functions and performance required for the control circuit 16,
The control circuit 16 may be realized by dedicated hardware instead of the CPU.

<1.6 Effects> According to the IC card 100 of the present embodiment described above, the reader / writer 200 issues the column read command, and thereby, once, obtains the status information of each page in the buffer area once. The latest written page can be detected from this. Then, a write pointer and a read pointer to the buffer area are obtained from the detected latest write page, and a write command or a read command is issued using the obtained pointer, so that the buffer area in the IC card can be accessed as a ring buffer. it can. Therefore, in the conventional example in which all pages in the buffer area are read in order to detect the latest write page, and in the conventional example in which a pointer indicating the latest write page is stored in an EEPROM (corresponding to the memory 18 in FIG. 1). In comparison, reading and writing of history information to and from the ring buffer is speeded up.

Although the non-contact type IC card has been described above as an example, the contact type IC card also has a different interface with the reader / writer 200 such as a receiving unit and a transmitting unit. A read command can be realized, and a similar effect can be obtained.

<1.7 Modified Example> I of the First Embodiment
The C card 100 has only a read / write function, but when the control circuit 16 is realized by using a CPU, the CPU detects the latest write page in the buffer area, and reads the read pointer and the read pointer. The write pointer can be held in the IC card 100 (in the control circuit 16). In this case, the reader / writer 200 issues a read command without designating a read pointer and issues a write command without designating a write command, thereby using the buffer area in the IC card 100 as a ring buffer. can do. Further, in this case, the IC card 100 detects the latest write page and reads the read pointer and the read pointer from when the power supply is started and the read command or the write command is issued from the reader / writer 200 after entering the operation area. It is desirable to set a write pointer. In the case of an IC card including an analog circuit such as a non-contact type IC card,
In particular, such a configuration is effective. In the non-contact type IC card, it is necessary to wait until the operation of the analog circuit becomes stable even when the power supply is started and the digital circuit becomes operable. During this waiting period, the digital circuit sets the read pointer and the write pointer. Is performed, time can be used effectively, and as a result, reading and writing to and from the ring buffer in the IC card can be substantially speeded up.

Embodiment 2 <2.1 Overall Configuration and Operation> Next, an IC card according to a second embodiment of the present invention will be described. This IC
The schematic configuration of the card is the same as that of the first embodiment and is as shown in FIG. 1, and this embodiment will also be described with reference to FIG.

In the IC card 100 of the present embodiment, as shown in FIG. 7, each page constituting a buffer area used as a ring buffer in the memory 18 has 1-bit status information (hereinafter referred to as "status bits"). )
And a data area a2 for storing history information. The setting of the status bit is performed by the control circuit 16 in the IC card 100, and the setting of the read pointer and the write pointer for using this buffer area as a ring buffer is also performed by the control circuit 16. The configuration of the control circuit 16 of the present embodiment is also the same as that of the first embodiment, and includes a CPU and a memory for storing a predetermined program, and the like. The control operation for the output circuit 14 is realized.

<2.2 Detailed Operation of Main Part> In this embodiment, the status bit of each page in the buffer area is initialized to “0” in advance, and the reader / writer 200
When the history information is written to the buffer area upon receiving a write command from the CPU, the status bit of the page to which the history information is written is inverted (this corresponds to the update of the status information). That is, when the history information is first written into the data area a2 of a certain page, the status bit of the page is set to "1", and thereafter, the writing of the history information continues, the loop goes around the ring buffer, and the page is returned to the page again. When the history information is written, the status bit of the page is set to “0”. In the present embodiment, the control circuit 16 in the IC card detects the latest written page by referring to the status bits of each page set as described above, and based on the detected latest written page, The read pointer and the write pointer are set and held in the control circuit 16. As described above, in the case of a non-contact IC card as in the present embodiment, a read command or a write command is issued from the reader / writer 200 after the IC card enters the operation area and power supply is started. By the time, it is desirable to set the read pointer and the write pointer. Therefore, in the present embodiment, after the supply of power to the IC card 100 is started, the control circuit 16 operates as shown in the flowchart of FIG. 8 to set the read pointer and the write pointer.

That is, first, the status bit of page 1, which is the first page of the buffer area used as the ring buffer, is read and set as STAa (step S30). Next, after setting the variable k indicating the page number to 2 (step S32), the status bit of the page k is read out and set as STAb. Then, STAa and STAb, which are the status bits of two consecutive pages,
It is determined whether or not are equal (step S36). STA
If a and STAb are equal, the process proceeds to step S38, and it is determined whether page k is the last page of the buffer area used as the ring buffer. As a result, if it is not the last page, the value of k is incremented by 1 (step S40), the value of STAa is replaced with the value of STAb (step S42), and the process returns to step S34. Thereafter, S, which is the status bit of two consecutive pages,
Unless TAa and STAb are equal and page k is not the last page of the buffer area, steps S34 → S
The loop of 36 → S38 → S40 → S42 is repeatedly executed.

During the execution of this loop, STAa and STA
If b is different, the process proceeds to step S44. In this case, since the page k-1 including the status bit STAa is the latest write page, the read pointer Rptr is set to k-1 and the write pointer Wptr is set to k (FIG. 7A).
reference).

If it is determined in step S38 that page k is the last page during the execution of the above loop, that is, if the status bits of all pages in the buffer area are the same, the process proceeds to step S46.
In this case, the read pointer Rptr is set to k, and the write pointer Wptr is set to 1 (see FIG. 7B).

<2.3 Effects> As described above, according to the present embodiment, the latest write page is detected by the 1-bit status provided for each page, so that the memory capacity can be reduced. The control circuit 16 for setting the write pointer and the read pointer includes a CPU and a memory for storing a program to be executed by the CPU. The setting process is realized by dedicated hardware. You can also. In this case, since the latest write page is detected based on the 1-bit status provided for each page, there is an advantage that the configuration of the dedicated hardware is simplified.

<2.4 Others> The write command and the read command in the present embodiment are executed in the following manner.
This is basically the same as the case of the first embodiment (see FIGS. 5 and 6). However, in this embodiment, when writing or reading history information to or from the ring buffer,
The page to be written or read is not specified by a write command or a read command, but is specified by a write pointer or a read pointer stored in the control circuit 16 of the IC card 100. Therefore, in this case, the PA register is not used for generating an address for accessing the memory 18, and the write pointer or the read pointer is used.

Embodiment 3 <3.1 Overall Configuration and Operation> Next, an IC card according to a third embodiment of the present invention will be described. This IC
In the card, the status bit of each page of the buffer area used as a ring buffer in the memory 18 is composed of three bits, and a majority decision process is performed when the latest written page is detected for setting the write pointer and the read pointer. Is different from the second embodiment.
This is the same as in the second embodiment. Therefore, hereinafter, only the operation of the control circuit 16 for setting the write pointer and the read pointer in the present embodiment will be described with reference to FIG.
This will be described with reference to the flowchart of FIG.

<3.2 Detailed Operation of Principal Part> The flowchart of FIG. 11 corresponds to the flowchart of FIG. 8 in the second embodiment. As can be seen by comparing the two flowcharts, when setting STAa and STAb indicating the status bits of two consecutive pages, in the present embodiment, the value after the majority processing (3-bit value) is set (step S50). , S54), the latest written page is detected by comparing the three-bit status bits STAa and STAb after the majority processing (step S).
36).

The status bit of each page of the buffer area used as the ring buffer in this embodiment is either "000" or "111", and each time a page is written, the status bit of the page is changed. The value alternates between the two. However, memory 1
In some cases, values other than these two types are written as status bits due to a write error to 8 or the like, for example, as shown in FIG. 9A. According to the present embodiment, even in such a case, the most recently written page is detected using the status bits after the majority processing. That is, “101” becomes “111” and “00”
"1" is detected as "000", the latest write page is detected, and a write pointer Wptr and a read pointer Rptr are set in accordance with the result (see FIG. 9B). Therefore, even if a certain degree of memory write error or the like occurs, the write pointer Wptr and the read pointer Rptr are set correctly, and the reliability of the writing and reading operations for the ring buffer is improved.

Embodiment 4 <4.1 Overall Configuration and Operation> Next, an IC card according to a fourth embodiment of the present invention will be described. This IC
The card has a status area a1 in each page of a buffer area used as a ring buffer in the memory 18.
Is composed of 1 byte. As shown in FIG. 10, the status bits are stored in the 3-bit area as in the third embodiment, but the write confirmation data is stored in the remaining 5-bit area. Is stored. That is, every time data is written to the ring buffer, predetermined 5-bit data (for example, “10101”) is stored in the page to be written.
Fixed bit pattern) is written as write confirmation data, and then, when setting the write pointer or read pointer based on the detection of the latest write page in the ring buffer, or when reading data from the ring buffer, etc. Then, the write confirmation data of each page of the ring buffer and the page to be read is read, and it is determined whether the data (history information) written to the page is correct based on the read write confirmation data.

The hardware configuration of the IC card of this embodiment and the execution processing of each command are basically the same as those of the third embodiment (see FIGS. 1, 9 and 11). However, in the present embodiment, the operation of the control circuit 16 for setting the write pointer and the read pointer of the ring buffer and the like are slightly different due to the above-described characteristics due to the introduction of the write confirmation data. Hereinafter, the operation of the IC card of the present embodiment will be described focusing on this difference.

<4.2 Detailed Operation of Main Part><4.2.1 Setting of Pointer> The processing for setting the write pointer and the read pointer of the ring buffer in this embodiment is the same as that of the third embodiment. The latest written page is detected using the majority decision processing using the three status bits (steps S50 to S50 in FIG. 11).
See S62). However, the read pointer Rptr and the write pointer Wptr are determined based on the detected latest write page.
Are different in the contents of the processing for setting. That is, FIG.
12 is performed instead of step S64 in FIG. 1 (hereinafter, referred to as “pointer setting process A”), and FIG. 12 is replaced with step S66 in FIG.
The processing shown in (b) (hereinafter referred to as “pointer setting processing B”) is performed.

The pointer setting process A in FIG. 12A is a process performed when the status bit values (values after majority processing) are different between pages k-1 and k, which are two consecutive pages in the ring buffer. It is. In this case, the write confirmation data is read from the status area a1 in the page k-1 (step S150), and it is determined whether the read write confirmation data is equal to a predetermined value (step S152). As a result, if the value is equal to a predetermined value, it is determined that the data has been correctly written to the page k-1, the page k-1 is determined to be the latest write page, and the read pointer Rptr is set to k-1. Then, the write pointer Wptr is set to k (step S16).
0).

In step S152, page k-1
When it is determined that the write confirmation data read from the page is not equal to the predetermined value, it is determined that the data is not correctly written in the page k-1. In this case, the pointer is set assuming that the page immediately before the page k-1 is the latest write page. That is, in this case, the process proceeds to step S154 to determine whether the page number k is 2 (step S154). If k is not 2, it is determined that page k-2 is the latest write page and the read pointer Rptr is set. set to k-2 and set the write pointer Wptr to k
It is set to -1 (step S162). If k is 2, the last page N of the buffer area is determined to be the latest write page, the read pointer Rptr is set to the last page N, and the write pointer Wptr is set to 1 (step S).
156).

The pointer setting process B shown in FIG. 12B is a process in the case where the status bit values (values after the majority decision process) of each page in the ring buffer are all the same. In this case, the write confirmation data is read from the status area a1 in the page k, that is, the last page N (step S170), and it is determined whether the read write confirmation data is equal to a predetermined value (step S17).
2). As a result, if the value is equal to the predetermined value, it is determined that the data is correctly written in the page k.
In this case, assuming that the status bits of all pages in the ring buffer are the same value and that page k is the latest write page, the read pointer Rptr is set to k (the last page N), and the write pointer Wptr is set to It is set to 1 (step S176).

If it is determined in step S172 that the write confirmation data read from page k is not equal to the predetermined value, it is determined that the data is not correctly written on page k (the last page N). I do.
In this case, assuming that the page k-1 immediately before the page k is the latest write page, the read pointer Rptr is set to k-1.
Is set, and the write pointer Wptr is set to k (step S174).

<4.2.2 Write Command Execution Process> FIG. 13 is a flowchart showing the procedure of a write command execution process (step S18 in FIG. 3) for writing history information to the ring buffer in the present embodiment. is there.
In this case, the read pointer Rptr and the write pointer Wp obtained by the above-described pointer setting process (FIG. 12, etc.)
The control circuit 16 holds tr in advance, and the page to be written is not specified by the write command, and the history information is sent from the reader / writer 200 together with the write command as write data. When recognizing the write command, the control circuit 16 uses the read pointer Rptr and the write pointer Wptr held in the control circuit 16 to store the data in the memory 18.
Then, an address for performing reading and writing for is generated (step S220). Next, after reading the status bit of the page indicated by the read pointer Rptr using the generated address (step S22).
2) Write the history information sent from the reader / writer 200 together with the write command to the ring buffer in the memory 18 (step S224). At this time, EEPR
For the memory 18 which is an OM, 1
The data for the page is written, and the status area a1 of the page is set as a status bit in step S2.
The value of the status bit read at 22 is written. However, when the status bits of all pages are the same (when the read pointer Rptr points to the last page of the buffer area as shown in FIG. 7B), the inverted value of the status bits read in step S222 is Written. By such writing, the value of the status bit of the page indicated by the write pointer Wptr is inverted. Further, predetermined data (for example, a fixed bit pattern “10101”) is written as write confirmation data in the status area a1 of the page pointed to by the write pointer Wptr. As described above, the status bit of the page indicated by the write pointer Wptr is updated, and it is possible to check later whether or not the current writing of this page has been correctly performed. When writing to the page indicated by the write pointer Wptr is completed, a response to the write command is transmitted to the reader / writer 200 (step S22).
6). Thus, the execution of the write command ends.

<4.2.3 Read Command Execution Processing> FIG. 14 is a flowchart showing the procedure of a read command execution processing (step S20 in FIG. 3) for reading history information from the ring buffer. In this case, the control circuit 16 previously holds the read pointer Rptr obtained by the above-described pointer setting process (FIG. 12, etc.), and the read command does not specify the page to be read. When the control circuit 16 recognizes the read command, the control circuit 16
An address for reading data from the memory 18 is generated using the read pointer Rptr stored in the memory (step S230). Next, using this address,
The history information is read from the ring buffer in the memory 18 (Step S232). Then, the read history information is transmitted to the reader / writer 200 (step S
234). Thus, the execution of the read command ends.

<4.3 Effect> According to the present embodiment, I
Each time the history information is written to the ring buffer of the C card 100, the write confirmation data is also written (see step S224 in FIG. 13). Thereafter, when the IC card enters the operation area and sets the write pointer Wptr and the read pointer Rptr for reading or writing to the ring buffer, the write confirmation data of the page detected as the latest write page is checked. You. By this check, it is checked whether or not writing to the page has been performed correctly (steps S152 and S152 in FIG. 12).
172), if the writing has not been correctly performed, the page immediately before that page is determined to be the latest written page, and the write pointer Wptr of the ring buffer is determined.
And the read pointer Rptr are set (steps S156, S162, S174, S176 in FIG. 12). Therefore, for example, if the IC card in the middle of writing data comes out of the operation area, the writing of the data will not be performed correctly. However, the pointer setting process using the write confirmation data (FIG. 12) )), Such an I
The page of the write failure to the C card is recognized, and the write pointer Wptr and read pointer Rptr of the ring buffer are set in a form in which the data of the write failure is removed. As a result, subsequent access to the ring buffer is performed correctly.

In the above embodiment, it is assumed that the ring buffer pointer setting process (FIG. 12) is always executed before the read command execution process (FIG. 14). Need not check the write confirmation data. However, in consideration of cases other than the above, even in the execution process of the read command, it may be determined whether or not the history information of the page to be read has been correctly written by checking the write confirmation data. Good.

<4.4 Modification> In the fourth embodiment, it is assumed that a predetermined fixed bit pattern is used as write confirmation data, and the write confirmation data is status information of a page in which it is stored. Although it is irrelevant to other data, the data associated with other data (such as history information) other than the status information of the page, for example, an error detection code or the like may be used as the write confirmation data.

In the fourth embodiment, five bits excluding the three status bits in the one-byte status area a1 in each page are used as areas for write confirmation data (see FIG. 10). The status area a1 may be extended by one or more bytes (the number of extended bytes is preferably an integer for convenience of access to the memory 18), and the extended area may be used as a storage area for the write confirmation data. When the number of bits of the write confirmation data is increased in this manner, the above-described write failure can be more accurately detected, and the write failure can be dealt with based on the detection result. The reliability of the writing and reading operations can be further improved.

[0061]

According to the first IC card of the present invention, each page constituting a storage area used as a ring buffer stores status information indicating writing to a data area on the page. When a predetermined command is issued from an external data read / write device, status information of each page in the storage area is read and sent to the data read / write device. Therefore, the data read / write device obtains status information of all pages of the ring buffer realized in the IC card by issuing a predetermined command only once, and detects the latest write page based on the status information. The write pointer and the read pointer for the ring buffer can be obtained from the latest write page. Therefore, in comparison with the conventional example in which all pages in the buffer area are read in order to detect the latest write page and the conventional example in which a pointer indicating the latest write page is stored in an EEPROM (nonvolatile memory), The reading and writing of the data are speeded up. In the conventional example in which the pointer indicating the latest write page is stored in the EEPROM, the problem of deterioration of the EEPROM due to a large number of rewrites of the pointer area is a problem. Will be resolved.

According to the second IC card of the present invention,
The status information stored in the status area of each page constituting the storage area used as the ring buffer is initialized to the same value in advance, and when writing is performed on the ring buffer, the page to be written is Are inverted.
Then, the status information of each such page is sequentially read, and the status information of two consecutive pages is compared to detect the latest write page in the ring buffer. Reading and writing are performed. Therefore, according to the present IC card, the write pointer and the read pointer for the ring buffer can be acquired in the IC card in a short time, and the buffer for detecting the latest write page can be obtained similarly to the first IC card. Compared to the conventional example in which all pages in the area are read, or the conventional example in which a pointer indicating the latest write page is stored in the EEPROM, reading and writing to the ring buffer are speeded up.

According to the third IC card of the present invention,
The same operation as that of the second IC card is performed, but since the status information of each page of the ring buffer is composed of one bit, the memory in the IC card is efficiently used, and the memory capacity is reduced. . Further, the amount of hardware for detecting the latest written page in the ring buffer from the status information is reduced.

According to the fourth IC card of the present invention,
In the configuration of the second IC card, the status information is composed of an odd number of bits, the odd number of bits are initialized so as to have the same value, and usually, the status information is updated along with writing to the ring buffer. All bits constituting the status information will have the same value later, but when detecting the latest write page of the ring buffer, the value after majority operation on the status information read from each page is used. You. Therefore, even if all bits constituting each status information are not the same due to a write error to the memory or the like, if the majority of the number of bits of each status information is the same value, the latest written page is correctly detected. As a result, the reliability of reading from and writing to the ring buffer is improved.

According to the fifth IC card of the present invention,
After the power supply to the IC card is started and before a command is received from the data reading / writing device, a page value (read pointer) indicating a reading position with respect to the ring buffer and a page value (write pointer) indicating a writing position are set. can get. Therefore, in the case of an IC card having an analog circuit such as a non-contact IC card, the read pointer and the write operation are performed by the digital circuit by utilizing the standby time from the start of power supply until the operation of the analog circuit is stabilized. The pointer will be set. As a result, time is effectively used, and as a result, reading and writing to and from the ring buffer of the IC card is substantially speeded up.

According to the sixth IC card of the present invention,
In any one of the second to fourth IC cards, after power supply is started and before a command is received from the data read / write device, the latest write page in the ring buffer is detected. Then, reading or writing to the ring buffer is performed based on the latest write page. Therefore, the fifth I
Like the C card, in the case of an IC card having an analog circuit such as a non-contact IC card, the digital circuit uses the latest wait time until the operation of the analog circuit is stabilized after the power supply is started. A write page is detected, thereby substantially speeding up reading and writing to the ring buffer of the IC card.

According to the seventh IC card of the present invention,
An area for storing write confirmation data in addition to the status information is provided in the status area of each page of the ring buffer, and the write buffer stores the write confirmation data when writing to the ring buffer. It can be determined whether or not the writing to has been performed correctly. Since a write failure can be dealt with based on this determination result, the reliability of reading and writing to the ring buffer can be improved.

According to the eighth IC card of the present invention,
The same write confirmation data as that of the seventh IC card is introduced. When the latest write page is detected by sequentially reading the status information of each page of the ring buffer, the data of the latest write page is deleted. If the data has not been correctly written, the page immediately before the latest written page is set as the latest written page again based on the write confirmation data of the latest written page. As a result, the subsequent access to the ring buffer can be correctly performed in a form in which the page with the write failure has been removed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an IC card according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a buffer area used as a ring buffer.

FIG. 3 is a flowchart showing an overall operation in the first embodiment.

FIG. 4 is a flowchart showing execution of a column read command according to the first embodiment.

FIG. 5 is a flowchart showing execution of a write command according to the first embodiment.

FIG. 6 is a flowchart showing execution of a read command according to the first embodiment.

FIG. 7 is a diagram showing a configuration of a buffer area according to the second embodiment of the present invention.

FIG. 8 shows a read pointer R according to the second embodiment.
9 is a flowchart showing the setting of a ptr and a write pointer Wptr.

FIG. 9 is a diagram showing a configuration of a buffer area according to a third embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a status area according to a fourth embodiment of the present invention.

FIG. 11 is a flowchart showing setting of a read pointer Rptr and a write pointer Wptr in the third embodiment.

FIG. 12 is a flowchart showing a main part of setting a read pointer Rptr and a write pointer Wptr in the fourth embodiment.

FIG. 13 is a flowchart showing execution of a write command according to the fourth embodiment.

FIG. 14 is a flowchart showing execution of a read command according to the fourth embodiment.

FIG. 15 is a view for explaining the realization of a ring buffer in an IC card.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 IC card 200 Reader / writer 10 Antenna 12 Modulation / demodulation circuit 14 Input / output circuit 16 Control circuit 18 Memory (EEPROM)

Claims (8)

[Claims] A command is received from a data read / write device, and the data read / write is performed based on the received command.
An IC card for exchanging data with a writing device, a receiving unit for receiving data including a command from the data reading / writing device, a transmitting unit for sending data to the data reading / writing device, A storage area configured by collecting a plurality of pages including a data area for storing data received from the data read / write device and a status area for storing status information indicating writing to the data area. Storage means having a storage area used as a ring buffer, and when data received from the data read / write device is written to the data area, a status area of a page including the data area to which the data is written Writing control means for writing status information indicating the writing to the data read / write device; When a predetermined command is received by the receiving means as the data, the status information stored in the status area is sequentially read for all pages in the storage area, and the read status information is transmitted to the data reading / writing device by the transmitting means. An IC card comprising: 2. A data read / write device receives a command from a data read / write device, and receives the data read / write device based on the received command.
An IC card for exchanging data with a writing device, a receiving unit for receiving data including a command from the data reading / writing device, a transmitting unit for sending data to the data reading / writing device, A storage area configured by collecting a plurality of pages including a data area for storing data received from the data read / write device and a status area for storing status information indicating writing to the data area. Storage means having a storage area used as a ring buffer, and status information of all pages constituting the storage area are initialized to the same value in advance, and data received from the data read / write device is stored in the storage means. When writing to the data area, status information of a page including the data area to which the data is written is configured. Writing control means for inverting the value of the bit to be read, and sequentially reading status information of each page in the storage area, and when the value of the read status information is different from the value of the status information read immediately before, The page in which the read status information is stored is the latest write page in which the latest write has been performed in the data area. If the read status information value is the same for all pages in the storage area, the page is read last. And a ring buffer control unit that controls reading and writing of data to and from the storage area used as a ring buffer on the basis of the page in which the status information is stored as a latest written page based on the latest written page. An IC card, characterized in that: 3. The IC card according to claim 2, wherein said status information comprises one bit. 4. The IC card according to claim 2, wherein the status information includes an odd number of bits, and the write control unit determines that all of the values of the odd number of bits forming the status information are the same. The ring buffer control unit generates status information not including bits having different values by majority operation on the read status information, and replaces the read status information with status information generated by the majority operation. An IC card for detecting a latest write page by using the IC card. 5. A data read / write device receives a command from a data read / write device, and reads the data read / write device based on the received command.
An IC card for exchanging data with a writing device, a receiving unit for receiving data including a command from the data reading / writing device, a transmitting unit for sending data to the data reading / writing device, Storage means having a storage area configured by collecting a plurality of pages including an area for storing data received from the data read / write device and being used as a ring buffer; A ring buffer control means for detecting a page value indicating a read position or a write position for use as a buffer after power supply to the IC card is started and before receiving a command from the data read / write device; IC comprising:
card. 6. The IC card according to claim 2, wherein said ring buffer control means issues a command from said data read / write device after power supply to said IC card is started. Detecting the latest write page before receiving the IC card. 7. The IC card according to claim 2, wherein a size of a status area of each page in the storage area is an integer byte, and an area other than an area used for storing status information in the status area. A write confirmation data area, wherein the write control means writes data received from the data read / write device into the data area,
The value of the bit forming the status information of the page including the data area in which the data is written is inverted, and the data is correctly written in the data area in the write confirmation data area in the status area of the page. An IC card for writing data for confirming whether or not the IC card has been activated. 8. The IC card according to claim 7, wherein said ring buffer control means: i) when a latest write page is detected by reading status information of each page in said storage area, Determining means for reading the write confirmation data of the write page and determining whether or not data has been correctly written in the data area of the latest write page based on the write confirmation data; ii) the latest book And a latest write page changing unit that, when it is determined that data is not correctly written in the data area of the new write page, sets a page immediately before the latest write page as a new write page. IC card.