KR100273614B1 - Ic card - Google Patents

Abstract

The present invention relates to realizing a ring buffer that can be accessed at high speed in an IC card.

In the present invention, the following column read command is prepared. When a column read command is issued from a reader-writer, the first page of the read destination buffer area designated by the command is set in the PA register in the IC card. Next, an address for reading, for example, the first byte of 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 same. This read operation is repeated while incrementing the value of the PA register, and reading up to the last page of the buffer area transmits all read data to the read write unit. The read write unit reads the status information of all pages of the ring buffer at once by this column read command to detect the latest write page, and reads / writes the ring buffer based on the read write unit.

Description

IC card

The present invention relates to an IC card for receiving data between data read / write devices.

The IC card carries data between the data read / write devices, and can be used, for example, for various transactions. At this time, history information such as transactions is often stored in the 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 becomes full as the area for storing the history information, the oldest data in the memory area is erased and the erased area is deleted. The latest data will be written. Therefore, when the IC card stores historical information such as a transaction, it is necessary to realize a ring buffer in the IC card.

In the IC card, an EEPROM (Electrically Erasable Programmable Read Only Memory) (electrically erasable writable ROM) is usually used as a memory for storing data. EEPROM requires time to write, and writing is often performed in units of a predetermined size (for example, 16 bytes) called a page. On the other hand, the unit of data viewed from the application side of the IC card is called a file, and in general, the file size is often set to be the same as the page size. When such a IC card realizes a ring buffer to store transaction history information, as shown in Fig. 15A, a predetermined area composed of a plurality of pages provided as a ring buffer area in the memory of the IC card is provided. , In order from the first page 1, history information 1, history information 2,... The writing is performed like the history information n. If a write request occurs after writing to the last page n again, the latest history information n + 1 is overwritten on the first page 1 on which the oldest history information 1 is written (Fig. 15 (b)). , (c)).

In the realization of the ring buffer, a reading pointer indicating a position to be read from the ring buffer and a writing pointer indicating a position to be written are usually provided. When the IC card stores historical information such as a transaction, reading is performed. The pointer is supposed to point to the most recently written page. Thus, the write pointer is always intended to point to the next page of the read pointer. As a result, in either of reading and writing to the ring buffer, substantially only a pointer (hereinafter referred to as "latest writing pointer") pointing to the page on which the most recent history information is written (latest writing page) can be obtained. All you need is

As described above, when the data read / write device (hereinafter referred to as "reader") reads or writes history information to an IC card having a memory that uses a predetermined area as a ring buffer, it writes to the IC card. After powering up, we need to get the latest write pointer value in the ring buffer. On the other hand, in the conventional IC card in which the ring buffer is realized, the contents of each page constituting the ring buffer are searched to find the latest written page (hereinafter, the IC card employing this method is referred to as "prior example 1"). Alternatively, an area for storing the latest write pointer was separately provided in a memory (nonvolatile memory such as EEPROM) of the IC card (hereinafter, an IC card employing this method is referred to as "conventional example 2"). Some IC cards have a CPU (Central Processing Unit) or the like and have an information processing function and only a read / write function. An IC card having an information processing function has an external read / write device. When reading or writing the history information from the IC card, the contents of each page constituting the ring buffer are searched inside the IC card to find the latest write page, or a storage area for the latest write pointer (hereinafter referred to as a "pointer area"). The latest write pointer value was obtained by reading the value stored in. On the other hand, in the case of an IC card having only a read / write function, an external read / write device reads the data in the ring buffer area from the IC card to start searching for the latest write page, or the latest write pointer in the pointer area of the IC card. By reading, the latest write pointer value was obtained.

In conventional IC cards, data cannot be read or written only in units of pages (e.g., 16 columns in a row). When the area for the latest write pointer is not provided in the memory, in order to find the latest write page. In addition, all data in the storage area allocated to the ring buffer must be read in units of pages. As a result, access to the ring buffer was very time consuming.

On the other hand, in the case where the pointer area is provided in the memory, each time the history information is written, the pointer area must be written to update the latest write pointer, and this pointer area is stored in the nonvolatile memory (usually EEPROM). Since it is prepared, the writing takes time. As a result, it took a long time to write history information. In addition, when the pointer area is provided in the EEPROM or the like, the deterioration of the EEPROM due to the increased number of rewrites of the pointer area also becomes a problem.

It is therefore an object of the present invention to provide an IC card which realizes a ring buffer which can be accessed at high speed without providing a pointer area in a nonvolatile memory.

1 is a block diagram showing a schematic configuration of an IC card of Embodiment 1 of the present invention;

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

3 is a flowchart showing the overall operation in the first embodiment described above;

4 is a flowchart showing execution of a column read command in the first embodiment described above;

5 is a flowchart showing execution of a write command in the first embodiment described above;

6 is a flowchart showing execution of a read command in the first embodiment described above;

7 is a diagram showing the configuration of a buffer area in a second embodiment of the present invention;

8 is a flowchart showing the setting of the read pointer Rptr and the write pointer Wptr in the second embodiment;

9 is a diagram showing the configuration of a buffer area in a third embodiment of the present invention;

10 is a diagram showing the configuration of a state area in a fourth embodiment of the present invention;

11 is a flowchart showing settings of the read pointer Rptr and the write pointer Wptr in the above-described third embodiment;

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

13 is a flowchart showing execution of a write command in the fourth embodiment;

14 is a flowchart showing execution of a read command in the fourth embodiment;

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

Explanation of symbols for the main parts of the drawings

100: IC card 200: reader

10: antenna 12: modulation and demodulation circuit

14 input / output circuit 16 control circuit

18: Memory (EEPROM)

A first IC card according to the present invention, which is made to solve the above problems, receives an instruction from a data read / write device and sends it to an IC card that receives data between the data read / write devices based on the received command. A receiving means for receiving data including a command from the data reading / writing device, Transmission means for sending data to the data reading / writing device, and Data for storing data received from the data reading / writing device A storage area comprising a plurality of pages including an area and a state area for storing state information indicating writing to the data area, the storage means having a storage area used as a ring buffer, and the data reading / writing When data received from the device is written into the data area, Write control means for writing status information indicating the write in a status area of a page including the data area in which the data is written, and receiving a predetermined command via the receiving means as data from the data reading / writing apparatus; And a read control means for sequentially reading the status information stored in the status area for all the pages in the storage area, and sending the read status information to the data read / write device via the transmission means. .

A second IC card according to the present invention is an IC card that receives a command from a data read / write device and receives data between the data read / write devices based on the received command, wherein the data read / write is performed. Receiving means for receiving data including a command from the apparatus, transmitting means for sending data to the data reading / writing apparatus, a data region for storing data received from the data reading / writing apparatus, and a corresponding data region. A storage area comprising a plurality of pages including a state area for storing state information indicating the writing of a storage device, the storage means having a storage area used as a ring buffer, and the status information of all pages constituting the storage area. Is initialized to the same value in advance, and the data read / write device is When the taken data is written into the data area, write control means for inverting the value of the bits constituting the status information of the page including the data area in which the data is written, and the status information of each page in the storage area sequentially. If the value of the state information read out by the readout is different from the value of the state information read immediately before, the page in which the state information read immediately before is stored is regarded as the latest write page in which the most recently written data has been written. When the value of the read status information is the same across all the pages in the storage area, the page used as the ring buffer based on the latest write page is used as the page on which the last read status information is stored as the latest write page. Ring buffer control means for controlling the reading and writing of data to and from the storage area And that is characterized.

In the third IC card according to the present invention, in the second IC card, the status information is characterized by one bit.

In a fourth IC card according to the present invention, in the second IC card, the state information is made up of odd bits, and the write control means is configured to determine the odd number of bits that constitute the state information. The ring buffer control means generates state information that does not include bits with different values by a majority vote operation on the read state information, and substitutes the read state information for the majority vote operation. By using the status information generated by the above, it is characterized in that the latest written page is detected.

A fifth IC card according to the present invention is an IC card that receives a command from a data read / write device and receives data between the data read / write devices based on the received command. A page including receiving means for receiving data including a command from a writing device, transmitting means for sending data to the data reading / writing device, and an area for storing data received from the data reading / writing device. A storage area constituted in a long manner, comprising: a storage means having a storage area 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; Ring buffer to detect after startup, before receiving commands from the data read / write device It characterized in that it comprises a control means.

The 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 is provided from the data reading / writing apparatus after power supply is started to the IC card. The latest write page is detected before receiving the command.

In the seventh IC card according to the present invention, in the second IC card, the size of the state area of each page in the storage area is an integer byte, and is used for storing state information in the state area. A write confirmation data area is provided as another area, and the write control means includes a page including the data area in which the data is written when data received from the data read / write device is written into the data area. And inverting the value of the bits constituting the state information of the data, and writing data for confirming whether or not the data is correctly written to the data area in the write confirmation data area in the status area of the page. It is done.

In the eighth IC card according to the present invention, in the seventh IC card, the ring buffer control means includes: i) the latest write page when the latest write page is detected by reading status information of each page in the storage area; Judging means for reading the write confirmation data of the write page and judging whether or not the data is correctly written in the data area of the latest write page by the write confirmation data; and ii) in the data area of the latest write page. When it is determined that the correct data has not been written, it is characterized by including the latest writing page changing means for making the immediately previous page of the latest writing page again into the latest writing page.

Embodiment of the Invention

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(Example 1)

〈1.1 Hardware Configuration〉

1 is a block diagram showing a schematic configuration of an IC card according to a first embodiment of the present invention. The IC card 100 is a non-contact type IC card that transmits and receives data between the read and write writers 200 by radio waves, and includes an antenna 10, a modulation / demodulation circuit 12, an input / output circuit 14, and the like. The control circuit 16 and the memory 18 are provided, and the input / output circuit 14, the control circuit 16, and the memory 18 are connected by a bus 20. In addition, the IC card 100 is provided with a power supply circuit (not shown) for supplying power to the respective portions.

In the IC card 100 of the above configuration, the antenna 10, the modulation / demodulation circuit 12, and the input / output circuit 14 function as receiving means for receiving data including a command from the read / write device 200. At the same time, it functions as a transmission means for transferring data from the IC card 100 to the reader / writer 200. The memory 18 is a nonvolatile storage means constituted by an EEPROM and stores data received from the read / write device 200 and the like. The control circuit 16 is configured by using a CPU and a memory for storing a predetermined program. The CPU executes a program to control operations of the input / output circuit 14 and the memory 18 and the like.

The read / write device 200 which transfers data to and from the IC card 100 always transmits radio waves, and the IC card 100 is predetermined to receive radio waves from the read / write device 200. It can operate within a range (this predetermined range is called "operation area").

When entering the operating area, the IC card 100 receives the radio wave from the read / write device 200 by the antenna 10, converts the electric signal into an electric signal, and converts the electric signal into a modulation / demodulation circuit 12 and a power supply circuit ( (Not shown). The power supply circuit supplies power by rectifying the electric signal and supplying the signal to each unit. The read / write unit 200 transmits unmodulated radio waves when the data is not transmitted to the IC card 100, and when the data is transmitted, radio waves in which the data is modulated and included in a carrier wave. To send.

<1.2 Outline of Operation>

When data is transmitted from the reader / writer 200 to the IC card 100, the demodulation circuit 12 demodulates the electrical signal supplied from the antenna 10 to extract data, and this is 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 same to the bus 20. The control circuit 16 operates in accordance with a command included in the data received from the read / write device 200 to control the input / output circuit 14 and the memory 18.

By this operation, the IC card 100 receives data from the read / write device 200 and stores the data in the memory 18, and also transfers the data stored in the memory 18 to the read-write device 200. do. As described above, the memory 18 is constituted by an EEPROM, and writing is executed in units of pages. In this embodiment, one page is 16 bytes. In addition, the reading and writing of data from the read / write device 200 to the memory 18 in the IC card 100 are in units of pages.

That is, when a command for requesting data writing (hereinafter referred to as a &quot; write command &quot;) is received from the read / write device 200, the control circuit 16 is transmitted with the write command in accordance with the write command. One page of data (16 bytes of data) is written into the memory 18. The page address indicating the write position to the memory 18 at this time is specified by the write command.

On the other hand, when a command for requesting data reading (hereinafter, referred to as a "read command") is received from the read / write device 200, the control circuit 16 requests desired one from the memory 18 according to the read command. Read data for pages. The page address indicating the read position from the memory 18 at this time is designated by the read command. The control circuit 16 transmits the read data to the input / output circuit 14 as parallel data via the bus 20, and the input / output circuit 14 converts the parallel data into serial data. The modulation and demodulation circuit 12 generates a signal in which the serial data is modulated into a carrier wave and included therein, and the antenna 10 transmits the signal as a radio wave.

<1.3 ring buffer realization>

In order to store the history information such as a transaction in the IC card 100 by using the above-described IC card 100 for various transactions, a ring buffer must be realized as described above (see Fig. 15). For this reason, in the present embodiment, a memory area composed of a plurality of consecutive pages in the memory 18 is secured as a buffer area, and the buffer area is read and written in units of pages between the read and write writers 200. It is an area for storing data to be performed. Each page in the buffer area consists of a data area a2 for storing history information and a state area a1 for storing state information indicating the writing of the history information to the data area a2, as shown in FIG. Then, the page address which is the value of the most recently written page (latest write page) is used as the read pointer, and the next page of the latest write page is used as the write pointer (provided that the latest write page is the last page in the buffer area. The page address at the head of the area is used as a write pointer), and the buffer area is written and read. Thus, the buffer area is used as the ring buffer.

Specifically, the read / write unit 200 designates a read pointer as the read page address in the read command and the write pointer as the write page address in the write command, so that the buffer area is used as the ring buffer. However, for this purpose, the read / write device 200 needs 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 this embodiment, a column read command is prepared to read status information indicating writing to each page in the buffer area at once. The column read command referred to herein reads data (for example, the first byte value) of the predetermined position of each page in the storage area of the predetermined range designated by the command from the IC card 100 by issuing a single command. Command to request. That is, the conventional read command can read data only by 16 bytes (for one page) in the "horizontal direction", but according to the column read command, a predetermined position (for example, 1 of each page) in a plurality of consecutive pages is read. Byte) data can be read in the "vertical direction (column direction)".

<1.4 Command Execution Process>

As described above, the operation of the IC card 100 of the present embodiment in which the column read command is prepared in addition to the write command and the read command will be described with reference to the flowchart shown in FIG. In the present embodiment, in the column read command, the buffer area to be read is designated by the page value, and the position of the reading target (for example, the first byte of each page) in each page in the buffer area is specified. It is assumed to be specified. In the write command, the value of the page to be written (for example, the write pointer) is designated, and in the read command, the value of the page to be read (for example, the read pointer) is designated.

When the IC card 100 enters the operation area and receives radio waves from the read / write device 200, and power supply to each part of the IC card 100 starts, first, initial setting is performed (step S10). As a result, the IC card 100 enters a state in which the command from the read / write unit 200 can be accepted. After the initial setting, it is in a state of waiting for a command to be transmitted from the read / write device 200 (step S12), and when a command is issued from the read / write device 200 and transmitted as a radio wave, the IC card 100 ) Receives this to the antenna 10 and transmits it to the control circuit 16 via the modulation / demodulation circuit 12 and the input / output circuit 14. The control circuit 16 analyzes the command (step S14), and executes the column read command execution process (step S16), the write command execution process (S18), and the read command execution process (depending on the type of the command). Any one of step S20) is performed.

<1.4.1 Column Read Command>

4 is a flowchart showing the procedure of executing the column read command (step S16 of FIG. 3). When the control circuit 16 recognizes a column read command, it first sets a value of the first page of the buffer area designated by the column read command to a predetermined register provided in the control circuit 16 (hereinafter referred to as a "PA register"). (Step S100), using the value of this PA register, an address (hereinafter referred to as "column address") for accessing the read target position designated by the column read command in the first page of the buffer area is generated (step). S102). For example, when the status area a1 intends to read status information of each page as the first byte of each page, an address of the first byte of the page indicated by the PA register is generated as a column address. When a column address is generated, data is read from the memory 18 (hereinafter referred to as &quot; column read data &quot;) of the first page reading target position using this to temporarily read the read column read data into the control circuit 16. (Step S104). Next, it is determined whether or not the value of the PA register is the last page value of the buffer area designated by the column read command, that is, whether 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 one (step S108), and the flow returns to step S102.

In the same manner, the steps S102? S104? S106? S108 are executed in the same manner so that the column read data of each page of the buffer area designated by the column read command is sequentially read out and stored in the control circuit 16. In the meantime, if it is determined in step S106 that the value of the PA register is the last page value of the buffer area, that is, it is determined that the column read data of the last page has been read, the process proceeds to step S110. At this point in time, the column read data of all the pages of the buffer area, that is, the data obtained by reading the buffer area in the column direction, is stored in the control circuit 16. In step S110, these data are stored for the column read command. As a response, the data is transmitted to the input / output circuit 14 to be sent to the read / write device 200, whereby the processing of the control circuit 16 for the column read command is terminated. In the column read command, for example, the entire buffer area to be used as the ring buffer is designated, and the position (for example, the first byte) of the state area a1 is designated as the read destination position. Information can be obtained.

The response transmitted to the input / output circuit 14 is sent out to the read / write unit 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 executing a write command (step S18 in FIG. 3) for writing history information into the ring buffer. In this case, in the write command, a write pointer for the ring buffer is designated as the page to be written, and history information is transferred from the read / write device 200 together with the write command as the write data. Upon recognizing the write command, the control circuit 16 first sets the write pointer, which is the page value designated by the write command, to the PA register provided in the control circuit 16 (step S120), and uses the value of the PA register. Thus, an address for writing to the memory 18 is generated (step S122). Using this address, the history information transmitted from the read / write unit 200 together with the write command is written into the ring buffer in the memory 18 (step S124). At this time, the writing also updates the status information on the page specified in the PA register, that is, the page indicated by the write pointer. Thereafter, a response to this write command is transmitted toward the read / write device 200 (step S126). As a result, execution of the write command is terminated.

<1.4.3 Read command>

FIG. 6 is a flowchart showing the procedure of the execution process of the read command (step S20 of FIG. 3) for reading the history information from the ring buffer. In this case, the read pointer for the ring buffer is designated as the page to be read in the read command. When the control circuit 16 recognizes a read command, first, it sets the read pointer which is the page value designated by the read command to the PA register provided in the control circuit 16 (step S130), and uses the value of this PA register. Thus, an address for reading data from the memory 18 is generated (step S132). Next, using this address, history information is read from the ring buffer in the memory 18 (step S134). Then, the read history information is transmitted toward the reader / writer 200 (step S136). As a result, execution of the read command is terminated.

<1.5 Other Configuration of Control Circuit>

The control circuit 16 of this embodiment which performs the above-mentioned operation is comprised by the CPU and the memory which stores a predetermined program etc., and includes the above-mentioned operation | movement with respect to a column read command by a CPU executing a program. (18) and control operations for the input / output circuit 14 are realized. However, as can be seen from the above description, the function to be realized by the control circuit 16 is to analyze the command issued from the read / write device 200 and to access the memory 16 in accordance with the command. It is to generate an address or to generate a control signal for executing a desired operation in the memory 16 and the input / output circuit 14, and these functions can be easily realized by hardware. Therefore, the control circuit 16 may be realized by dedicated hardware instead of the CPU by considering the cost, power consumption, and the like required for the current control of the CPU chip.

〈1.6 Effect〉

According to the IC card 100 of the present embodiment described above, the read / write unit 200 can obtain the state information of each page of the buffer area at once by issuing a column read command, and thereby detecting the latest write page. can do. The buffer area in the IC card can be accessed as a ring buffer by obtaining a write pointer and a read pointer for the buffer area from the detected latest write page and using this to issue a write command or a read command. Therefore, compared with the conventional example in which all pages of the buffer area have been read in order to detect the latest write page, or the conventional example in which a pointer indicating the latest write page is stored in the EEPROM (corresponding to the memory 18 in FIG. 1). The reading and writing of history information for the buffer is speeded up.

In the above description, the non-contact type IC card has been described as an example. However, in the contact type IC card, the interface with the read / write device 200, such as the receiving means and the transmitting means, is different. It is possible to achieve the same effect.

<1.7 modification>

The IC card 100 of the first embodiment has only a read / write function, but when the control circuit 16 is realized using a CPU, the CPU detects the latest write page in the buffer area. It is also possible to hold the read pointer and the write pointer in the IC card 100 (in the control circuit 16). In this case, the read / write device 200 can use the buffer area in the IC card 100 as a ring buffer by issuing a read command without specifying a read pointer and issuing a write command without specifying a write command. have. In this case, the IC card 100 detects the latest write page by entering the operation area and starting the power supply until a read command or a write command is issued from the read / write device 200, thereby reading the read pointer and the write. It is desirable to set a pointer. In the case of an IC card including an analog circuit such as a noncontact IC card or the like, such a configuration is particularly effective. The reason is that in the non-contact type IC card, even when the power supply is started and the digital circuit is enabled, the analog circuit must wait until the operation of the analog circuit is stabilized. In this waiting period, the read and write pointers are set by the digital circuit. This is because the time can be used efficiently, and as a result, the read and write to the ring buffer in the IC card is substantially speeded up.

(Example 2)

<2.1 General Configuration and Operation>

Next, the IC card of Embodiment 2 of the present invention will be described. The schematic configuration of this IC card is the same as that of the first embodiment and is shown in FIG. 1, and this embodiment will be described with reference to FIG.

In the IC card 100 of the present embodiment, as shown in Fig. 7, each page constituting the buffer area used as the ring buffer in the memory 18 is 1 bit of status information (hereinafter referred to as "status bit"). A status area a1 for storing the data and a data area a2 for storing the history information. The setting of the status bit is executed 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 the ring buffer is also executed 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 is composed of a CPU and a memory for storing a predetermined program, and the like. The memory 18 or the input / output circuit 14 is executed by the CPU executing the program. The control operation for is realized.

<2.2 Detailed Operations of Main Parts>

In this embodiment, the status bit of each page in the buffer area is initialized to "0" in advance, and when the write command is received from the read / write device 200 and the history information is written to the buffer area, the history information is written. The status bit of the page being reversed is reversed (this corresponds to updating of status information). In other words, when history information is first written to the data area a2 of a page, the status bit of the page is set to &quot; 1 &quot;. Then, writing of history information is continued, and the ring buffer is sequentially ordered again to the page. When the history information is written, the status bit of the page is set to "0". In this embodiment, in the IC card, the control circuit 16 detects the latest write page with reference to the status bits of each page set as described above, and reads out the buffer area based on the detected latest write page. The pointer and the write pointer are set and held in the control circuit 16. As described above, in the case of the non-contact type IC card as in the present embodiment, until the IC card enters the operation area and the supply of power is started until a read command or a write command is issued from the read / write device 200, It is preferable to set the read pointer and the write pointer. Thus, in this embodiment, after the power supply is started to the IC card 100, the control circuit 16 operates as shown in the flowchart of Fig. 8, whereby the read pointer and the write pointer are set.

That is, first, the status bit of page 1, which is the first page of the buffer area to be used as the ring buffer, is read out, and this is STAa (step S30). Next, after setting the variable k representing the page number to 2 (step S32), the status bit of the page k is read out to be STAb. Then, it is determined whether STAa and STAb which are status bits of two consecutive pages are the same (step S36). If STAa and STAb are the same, the flow advances to step S38 to determine 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, as long as STAa and STAb, which are status bits of two consecutive pages, are the same and page k is not the last page of the buffer area, a loop of steps S34-> S36-> S38-> S40-> S42 is repeatedly executed. do.

During the execution of this loop, if STAa and STAb are 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 (see Fig. 7A).

During the execution of the loop, if it is determined in step S38 that page k is the last page, i.e., if the status bits of all pages of the buffer area are the same, step S46 is reached. 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, since the latest write page is detected in the state of 1 bit provided in each page, the memory capacity is reduced. The control circuit 16 for setting the write pointer and the read pointer is composed of a CPU and a memory for storing a program executed by the CPU, but the setting process can be realized by dedicated hardware. Do. In this case, since the latest write page is detected in the state of 1 bit provided in each page, there is an advantage that the configuration of the dedicated hardware is simplified.

〈2.4 Others〉

The execution processing of the write command and the read command in the present embodiment is basically the same as in the case of the first embodiment (see Figs. 5 and 6). In the present embodiment, however, when writing or reading the history information to the ring buffer, the page to be written or read is not designated by the write command or the read command. This is specified by a write pointer or read pointer stored in the control circuit 16. Thus, in this case, the PA register is not used in generating an address for accessing the memory 18, and a write pointer or read pointer is used.

(Example 3)

<3.1 Overall Configuration and Operation>

Next, the IC card of Embodiment 3 of the present invention will be described. In the IC card, the status bit of each page of the buffer area to be used as the ring buffer in the memory 18 is 3 bits, and a majority voting process is performed when detecting the latest write page for setting the write pointer and read pointer. It differs from the said Example 2 and is the same as that of the said Example 2 about another point. Therefore, hereinafter, the operation of the control circuit 16 for setting the write pointer and read pointer in the present embodiment will be described with reference to the flowchart of FIG.

<3.2 Detailed operation of main parts>

The flowchart of FIG. 11 corresponds to the flowchart of FIG. 8 in Example 2. As shown in FIG. As can be seen by comparing the two flowcharts, in setting the STAa and the STAb indicating the status bits of two consecutive pages, in this embodiment, the value after the majority vote process (3 bit value) is set (step S50, S54), the latest write page is detected by comparing the 3-bit status bits STAa and STAb after the majority vote processing (step S56).

In this embodiment, the status bit of each page of the buffer area to be used as the ring buffer is either "000" or "11l", and each time a page is written, the value of the status bit of the page is It is alternated between the two. By the way, there are cases where values other than these two are written as status bits due to an error in writing to the memory 18, for example, as shown in Fig. 9A. According to this embodiment, even in this case, the latest write page is detected using the status bit after the majority vote process. That is, "101" is "111", "001" is "000", and the latest write page is detected, and the write pointer Wptr and the read pointer Rptr are set according to the result (see Fig. 9B). Therefore, even if some memory write error or the like occurs, the write pointer Wptr and the read pointer Rptr are set correctly, thereby improving the reliability of the write or read operation to the ring buffer.

(Example 4)

<4.1 Overall Configuration and Operation>

Next, the IC card of Embodiment 4 of the present invention will be described. In the IC card, the state area a1 in each page of the buffer area to be used as the ring buffer in the memory 18 is composed of 1 byte, and as shown in FIG. As in 3, the status bit is stored, but write confirmation data is stored in the remaining 5 bits. That is, each time a write is made to the ring buffer, predetermined 5-bit data (for example, a fixed bit pattern called "10101") is written into the page to be written as the write confirmation data, and then the latest in the ring buffer is written. At the time of setting a write pointer or read pointer based on detection of a write page, or reading data from the ring buffer, the write confirmation data of each page of the ring buffer or the page to be read is read and based on the read write confirmation data. It is determined whether the data (history information) written on the page is correct.

The hardware configuration of the IC card of the present embodiment, the execution processing of each command, and the like 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 differs slightly from the above characteristics by the introduction of the write confirmation data. The operation of the IC card of the present embodiment will be described below centering on this difference.

<4.2 Detailed operation of main part>

<4.2.1 Pointer setting>

In the processing for setting the write pointer and the read pointer of the ring buffer in the present embodiment, similarly to the third embodiment, the latest write page is detected while using the majority vote process using the 3-bit status bits (Fig. 11). See steps S50 to S62). However, the processing contents for setting the read pointer Rptr and the write pointer Wptr are different based on the detected latest write page. That is, the process shown in FIG. 12A (hereinafter referred to as "pointer setting process A") is performed instead of step S64 in FIG. 11, and in FIG. 12B instead of step S66 in FIG. The processing (hereinafter referred to as "pointer setting processing B") is performed.

The pointer setting processing A in Fig. 12A is processing when the value of the status bit (the value after the majority processing) differs between pages k-1 and k which are two consecutive pages in the ring buffer. In this case, the write confirmation data is read from the state area a1 in 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 it is equal to a predetermined value, the data is correctly written to the page k-1, the page kl is the latest write page, the read pointer Rptr is set to k-1, and the write pointer Wptr is k. (Step S160).

If it is determined in step S152 that the write confirmation data read from the page k-1 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 by assuming that the page preceding the page k-1 is the latest write page. That is, in this case, the flow advances to step S154 to determine whether the page number k is 2 (step S154). If k is not 2, the page k-2 is the latest write page, and the read pointer Rptr is k-2. The write pointer Wptr is set to k-1 (step S162). If k is 2, the last page N of the buffer area is assumed 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 S156).

The pointer setting processing B in FIG. 12B is a process in which the values (values after the majority processing) of the status bits of each page in the ring buffer are all the same. In this case, the write confirmation data is read from the state k of 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 S172). As a result, if it is equal to a predetermined value, it is assumed that data is correctly written to the page k. In this case, assuming that the status bits of all pages of the ring buffer are the same value, and that page k is the latest write page, the read pointer Rptr is set to k (final page N) and the write pointer Wptr is set to 1 ( Step S176).

In step S172, when it is determined that the write confirmation data read in page k is not equal to the predetermined value, it is determined that the data is not correctly written in the page k (final page N). In this case, it is assumed that the previous page k-1 of the page k is the latest write page, the read pointer Rptr is set to k-1, and the write pointer Wptr is set to k (step S174).

<4.2.2 Write command execution processing>

FIG. 13 is a flowchart showing the procedure of executing a write command (step S18 in FIG. 3) for writing history information into the ring buffer in this embodiment. In this case, the control circuit 16 holds in advance the read pointer Rptr and the write pointer Wptr obtained by the above pointer setting process (see FIG. 12, etc.), and the write target page is not specified, and the history information is not specified. Is sent from the read / write unit 200 together with the write command as write data. When the control circuit 16 recognizes the write command, the control circuit 16 uses the read pointer Rptr and the write pointer Wptr held in the control circuit 16 to generate an address for reading and writing to the memory 18 (step) S220). Next, using the generated address, after reading the status bits of the page indicated by the read pointer Rptr (step S222), the history information transferred from the read / write unit 200 with the write command is stored in the memory 18. Is written to the ring buffer (step S224). At this time, one page of data including the history information is written into the memory 18, which is an EEPROM, and the value of the status bit read in step S222 is written as the status bit in the status area a1 of the page. . However, when the status bits of all pages are the same (as shown in Fig. 7B) when the read pointer Rptr points to the last page of the buffer area, the inverted value of the status bits read in step S222 is Is written. This write reverses the value of the status bit of the page indicated by the write pointer Wptr. Furthermore, predetermined data (for example, a fixed bit pattern called "10101") is written as the write confirmation data in the state area a1 of the page indicated by the write pointer Wptr. As described above, the status bit of the page indicated by the write pointer Wptr is updated, and at the same time, it is possible to check whether or not this page has been correctly written. When writing to the page indicated by the write pointer Wptr is completed, a response to this write command is sent toward the read write unit 200 (step S226). As a result, execution of the write command is terminated.

<4.2.3 Read command execution processing>

FIG. 14 is a flowchart showing the procedure of executing a read command (step S20 of FIG. 3) for reading history information from the ring buffer. In this case, the control circuit 16 holds in advance the read pointer Rptr obtained by the pointer setting process (see FIG. 12, etc.), and the page to be read is not designated in the read command. When the control circuit 16 recognizes the read command, the control circuit 16 generates an address for reading data from the memory 18 using the read pointer Rptr held in the control circuit 16 (step S230). Next, using this address, history information is read from the ring buffer in the memory 18 (step S232). Then, the read history information is transmitted toward the reader / writer 200 (step S234). As a result, execution of the read command is terminated.

〈4.3 Effect〉

According to this embodiment, write confirmation data is also written every time history information is written into the ring buffer of the IC card 100 (see step S224 in FIG. 13). Then, when the IC card enters the operation area to set the write pointer Wptr and the read pointer Rptr to read or write the ring buffer, the write confirmation data of the page detected as the latest write page is checked. By this check, it is checked whether or not writing to the page has been executed correctly (see steps S152 and S172 in FIG. 12), and if writing is not done correctly, the page preceding the page is the latest writing page. By doing so, the write pointer Wptr and the read pointer Rptr of the ring buffer are set (steps S156, S162, S174, S176 in Fig. 12). Thus, for example, when the IC card is moved out of the operation area in the middle of writing data, writing of the data will not be executed correctly, but in such a pointer setting process (Fig. 12) using the write confirmation data described above, The write failure page is recognized, and the write pointer Wptr and the read pointer Rptr of the ring buffer are set in such a manner that the data of the write failure is removed. As a result, subsequent accesses to the ring buffer are performed correctly.

In the above embodiment, it is assumed that the pointer buffer setting processing (Fig. 12) of the ring buffer is executed before the execution processing of the read command (Fig. 14). There is no need to check. However, in consideration of the case other than the above, in the execution process of the read command, it may be determined whether or not the history information and the like of the page to be read are correctly written by checking the write confirmation data.

<4.4 modification>

In Embodiment 4 described above, the predetermined fixed bit pattern is used as the write confirmation data, so that the write confirmation data is independent of data other than the status information of the page in which it is stored, but other data than the status information of the page. What is related to (history information, etc.), such as an error detection code, may be used as write confirmation data.

In the fourth embodiment described above, five bits excluding the three bit status bits of the one-byte status area a1 in each page are used as the write confirmation data area (see FIG. 10). By extending the byte or more (it is preferable that the number of extended bytes be an integer byte for the convenience of access to the memory 18), the extended area may also be a storage area for write confirmation data. Increasing the number of bits of the write confirmation data in this way makes it possible to more accurately detect the above-described write failure and to cope with the write failure based on the detection result. Therefore, the write or read operation of the ring buffer in the IC card can be performed. The reliability can be further improved.

According to the first IC card according to the present invention, each page constituting a storage area to be used as a ring buffer stores state information indicating writing of the page to a data area, and is determined from an external data reading / writing device. Is issued, the status information of each page of the storage area is read and transmitted to the data reading / writing apparatus. Therefore, the data reading / writing apparatus only issues a predetermined command once, obtains the state information of all pages of the ring buffer realized in the IC card, detects the latest writing page based on this, A write pointer and a read pointer for the ring buffer can be obtained from the latest write page. Therefore, compared with the conventional example in which all pages of the buffer area have been read in order to detect the latest write page, or the conventional example in which a pointer indicating the latest write page is stored in EEPR0M (nonvolatile memory), the reading or writing to the ring buffer is performed. It is faster. In the conventional example in which the pointer indicating the latest write page is stored in the EEPROM, the deterioration of the EEPROM due to the increase in the number of rewrites of the pointer area becomes a problem. However, such an IC card also eliminates such a problem.

According to the second IC card according to the present invention, the state information stored in the state area of each page constituting the storage area to be used as the ring buffer is initialized to the same value in advance, and when writing is made to the ring buffer, The values of the bits constituting the state information of the write target page are reversed. By reading the status information of each of these pages sequentially and comparing the status information of two consecutive pages, the latest write page in the ring buffer is detected, and the read to the ring buffer is read based on the latest write page. Or writing is performed. Therefore, according to this IC card, it is possible to obtain a write pointer and a read pointer for a ring buffer in a short time in the IC card, and similarly to the first IC card, all pages of the buffer area are detected in order to detect the latest write page. Compared to the conventional example which was read and the conventional example which stored the pointer which shows the latest write page in EEPROM, reading and writing to a ring buffer are speeded up.

According to the third IC card according to the present invention, the same operation as that of the second IC card is performed, but since the state information of each page of the ring buffer is composed of 1 bit, the memory in the IC card is efficiently used, and the memory capacity This is reduced. The amount of hardware for detecting the latest write page in the ring buffer is also reduced from the state information.

According to the fourth IC card according to the present invention, in the configuration of the second IC card, the status information is composed of odd bits, and the odd bits are initialized so that all of the odd bits have the same value, and is usually written in a ring buffer. Even after updating of the state information, the bits constituting the state information become the same value. However, when detecting the latest write page of the ring buffer, the value after the majority vote operation on the state information read from each page is used. Therefore, even if the bits constituting each state information are not the same due to a write error in the memory or the like, if the majority of the number of bits of each state information is the same value, the latest write page is correctly detected. This improves the reliability of reading and writing to the ring buffer.

According to the fifth IC card according to the present invention, a page value (read pointer) indicating a read position to the ring buffer and a write position after receiving power from the IC card and before receiving a command from the data read / write apparatus You can get a page value (write pointer) indicating. Therefore, in the case of an IC card having an analog circuit such as a non-contact type IC card, the read pointer and the write pointer are set by the digital circuit using the waiting time from the start of power supply until the operation of the analog circuit is stabilized. Will be. As a result, time is efficiently used, and as a result, reading or writing to the ring buffer of the IC card becomes substantially faster.

According to the sixth IC card according to the present invention, in any one of the second to fourth IC cards, after the power supply is started, before receiving a command from the data read / write device, the ring buffer is used. The latest write page is detected, and then reading or writing to the ring buffer is performed based on this latest write page. Therefore, similar to the fifth IC card, in the case of an IC card having an analog circuit such as a non-contact type IC card, the digital circuit uses the waiting time from the start of power supply until the operation of the analog circuit is stabilized. The latest write page is detected, thereby substantially speeding up reading or writing to the ring buffer of the IC card.

According to the seventh IC card according to the present invention, an area for storing write confirmation data other than status information is provided in the status area of each page of the ring buffer, and the write confirmation data stored therein at the time of writing to the ring buffer is provided. It is possible to determine whether or not writing to the ring buffer has been correctly performed. Since writing failure can be coped with based on the 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, write confirmation data similar to the seventh IC card is introduced, and when the latest write page is detected by sequentially reading the status information of each page of the ring buffer, the latest When the data of the writing page is not correctly written, the page immediately before the latest writing page is made into the latest writing page again based on the writing confirmation data of the latest writing page. As a result, subsequent access to the ring buffer can be executed accurately in the form of eliminating the write bad page.

Claims (8)

An IC card that receives a command from a data read / write device and receives data between the data read / write devices based on the received command. Receiving means for receiving data including a command from the data reading / writing apparatus; Transmitting means for sending data to the data reading / writing device; A storage area comprising a plurality of pages including a data area for storing data received from the data reading / writing device and a status area for storing state information indicating writing to the data area, which is a ring buffer. Storage means having a storage area used; Write control means for writing state information indicating the write in a state area of a page including the data area in which the data is written, when data received from the data reading / writing apparatus is written into the data area; When a predetermined command is received by the receiving means as data from the data reading / writing apparatus, the status information stored in the status area is sequentially read for all the pages in the storage area, and the read status information is sent to the transmitting means. Reading control means for sending to the data reading / writing device IC card comprising a. An IC card that receives a command from a data read / write device and receives data between the data read / write devices based on the received command. Receiving means for receiving data including a command from the data reading / writing apparatus; Transmitting means for sending data to the data reading / writing device; A storage area comprising a plurality of pages including a data area for storing data received from the data reading / writing device and a status area for storing state information indicating writing to the data area, which is a ring buffer. Storage means having a storage area used; And including the data area in which the state information of all the pages constituting the storage area is initialized to the same value in advance, and when the data received from the data reading / writing apparatus is written into the data area. Write control means for inverting the value of bits constituting the page state information; If the status information of each page in the storage area is read sequentially and the value of the read status information is different from the value of the immediately read status information, the page in which the immediately read status information is stored is stored in the data area. If the most recently written page has been written most recently, and the value of the read status information is the same across all the pages in the storage area, the page where the last read status information has been stored is referred to as the latest write page. Ring buffer control means for controlling reading and writing of data to the storage area used as a ring buffer based on the latest write page IC card comprising a. The method of claim 2, And said status information consists of one bit. The method of claim 2, The state information is composed of odd bits, The write control means initializes the values of the odd bits constituting the state information to be the same, The ring buffer control means generates state information that does not include bits having different values by a majority vote operation on the read state information, and uses the state information generated by the majority vote operation instead of the read state information. To detect the latest registry page IC card, characterized in that. An IC card that receives a command from a data read / write device and receives data between the data read / write devices based on the received command. Receiving means for receiving data including a command from the data reading / writing apparatus; Transmitting means for sending data to the data reading / writing device; A storage area comprising a plurality of pages including areas for storing data received from the data reading / writing device, the storage means having a storage area used as a ring buffer, and Ring buffer control means for detecting a value of a page indicating a read position or a write position for using the storage area as a ring buffer before receiving a command from the data read / write device after power supply to the IC card is started; IC card comprising a. The method according to any one of claims 2 to 4, And the ring buffer control means detects the latest write page after power supply to the IC card is started and before receiving a command from the data read / write device. The method of claim 2, The size of the status area of each page in the storage area is an integer byte, and a write confirmation data area is provided as an area other than the area used for storing state information in the status area, The write control means inverts the value of a bit constituting the state information of a page including the data area in which the data is written, when writing data received from the data reading / writing apparatus into the data area; At the same time, writing data for confirming whether or not the data is correctly written to the data area is written in the write confirmation data area in the status area of the page. IC card, characterized in that. The method of claim 7, wherein The ring buffer control means, i) When the latest write page is detected by reading the status information of each page in the storage area, the write confirmation data of the latest write page is read and the data area of the latest write page is read by the write confirmation data. Judging means for judging whether or not the data has been correctly written into the ii) when it is determined that data is not correctly written in the data area of the latest writing page, the latest writing page changing means for making the page immediately preceding the latest writing page a new writing page again. IC card comprising a.