JP2008250426A - Read/write processing method, read/write processing apparatus and rfid tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a user to recognize that memory is garbled, and to acquire correct data. <P>SOLUTION: In writing of data in an RFID tag, data and a corresponding check code are written, and in the reading of data, the error of read data is detected by a CRC by using a check code, and when any error is detected, error correction by ECC is made, and the error of the corrected data is detected by CRC, and when the error of the corrected data is detected, a user is notified that the data are abnormal, and when any error is not detected, the user is notified that the error of data has been corrected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an RFID tag having a built-in semiconductor memory, a read / write processing apparatus and a read / write processing method for reading and writing information to and from the semiconductor memory by performing non-contact communication with the RFID tag.

  In recent years, a storage system in which various kinds of information are written is attached to goods to be transported, and a system that reads information in a non-contact manner by wireless communication with the storage medium has been introduced in the baggage management site and factory assembly lines. ing.

  This system is called an RFID system (Radio Frequency Identification System). The storage medium attached to the article contains an IC chip including a semiconductor memory, an antenna coil for communication, and the like, and is called an RFID tag or a non-contact IC tag.

In such an RFID system, when the data written in the memory in the RFID tag becomes abnormal due to some factor, that is, when the data changes to cause a so-called memory corruption, There is known a technique of detecting using (Cyclic Redundancy Check) (see, for example, Patent Document 1).
Japanese Patent No. 3007926

  In the above-mentioned Patent Document 1, when so-called memory corruption occurs, that is, when data in the memory changes, that is, when a data abnormality occurs, it is only detected and recognized by the user.

  Therefore, for example, the user knows that an abnormality has occurred in the read data suddenly one day due to the life of the RFID tag, and suddenly has to replace it with a new RFID tag. It was inconvenient.

  As a user, if correct data is obtained and it is possible to grasp that an abnormality is occurring, it is time to replace the RFID tag, or the memory environment is injured due to the use environment being hot, etc. It is possible to determine that the environment is likely to occur, and it is possible to take measures such as exchanging RFID tags in advance or changing the usage environment.

  The present invention has been made in view of the above-described points, and an object of the present invention is to enable a user to recognize when memory corruption occurs and to obtain correct data.

 (1) A read / write processing method of the present invention is a read / write processing method for reading and writing data to and from a memory of an RFID tag, wherein a write step of writing data and a corresponding check code into the memory, A read step of reading data and a corresponding check code; a first error detection step of detecting an error in the data read from the memory using the check code read from the memory; and the first An error correction step for correcting an error in the data when an error in the data is detected in the error detection step, and a second error detection step for detecting an error in the data after the error correction corrected in the error correction step And an error in the data after error correction is detected in the second error detection step. It is that the data is abnormal, and when an error of the data after the error correction is not detected are those comprising a notifying step for that corrects errors, informs.

  In the writing step, the data and the corresponding check code are written in the memory, and in the reading step, the data and the corresponding check code are read from the memory. This data includes user data stored in the RFID tag by the user. The user data is preferably so-called user data, which is data created by the user such as information meaningful to the user, for example, various information such as identification and work instructions related to the article to which the RFID tag is attached. Is preferred.

  For error detection, techniques such as parity, CRC (Cyclic Redundancy Code), checksum, etc. can be used, for example.

  For error correction, for example, a technique such as ECC (Error Correction Code) or majority decision can be used.

  The notification is preferably sent to a host device that commands reading and writing to the RFID tag.

  According to the read / write processing method of the present invention, when writing data, the data and the corresponding check code are written in the RFID tag memory, and when reading the data, the read check code is used to check for errors in the read data. If an error is detected, error correction is performed, and further, an error in the corrected data is detected. When an error in the corrected data is detected, the fact that the data is abnormal is notified and corrected. When no later data error is detected, the user is notified that the data error has been corrected, so the user can correct the error if the data read from the memory of the RFID tag has an abnormality such as memory corruption. It can be understood that the data was restored to the correct data by the error or that the correct data could not be restored by error correction. It becomes door.

  Therefore, the user can take measures such as exchanging the RFID tag or changing the use environment when abnormality occurs in the data and correct data is restored by error correction.

  As another embodiment of the present invention, in the error correction step, not only data but also check code errors may be corrected.

  (2) In one embodiment of the read / write processing method of the present invention, the check code is a CRC check code and an ECC check code, and in the first and second error detection steps, an error is detected by CRC, In the error correction step, an error of 1-bit data is corrected by ECC.

  In the RFID tag, the memory corruption usually starts with 1-bit data corruption. According to this embodiment, the ECC-corrected 1-bit data can be corrected to restore correct data.

  In addition, since error detection is performed on CRC after error correction by ECC, which has a higher detection rate of error detection than ECC, if there is an error in data after error correction, it is performed with high accuracy. Can be detected, so that the reliability is high.

  Furthermore, since the first error detection step by CRC is performed prior to the error correction step by ECC, it is not necessary to perform error correction by ECC unnecessarily for normal data occupying most of the processing, and the processing speed Can be improved.

  As another embodiment of the present invention, error correction by ECC is not limited to data, and a 1-bit error in a CRC check code may be corrected.

  (3) In the embodiment of (2), the memory has a user area and a plurality of mirror areas, and in the writing step, the same data is written in the user area and the plurality of mirror areas, respectively. The notification step is a first notification step. In the first notification step, when an error in the data after error correction is detected in the second error detection step, the fact that the data is abnormal is notified. Without any error, in the second error detection step, when an error in the data after error correction is detected, the data read from the user area and the mirror data respectively read from the plurality of mirror areas Based on the above, a step of creating new data by the majority match for each bit, and a third error detection for detecting an error of the created new data When the error of the new data is detected in step 3 and the third error detection step, the data is abnormal. If the error of the new data is not detected, the error is corrected. And a second notification step for notifying that the above has been performed.

  According to this embodiment, using the mirror data read from the plurality of mirror areas, the data error is corrected by the majority match for each bit to create new data. It can be corrected, and error detection by CRC is also performed for new data. If there is an error in the created new data, it can be notified, so that it is highly reliable. Become.

  (4) The read / write processing device of the present invention is a read / write processing device that reads and writes data to and from an RFID tag in a contactless manner, and transmits data to be written to the RFID tag and a corresponding check code to the RFID tag. Transmitting unit, receiving unit receiving data read from the RFID tag and corresponding check code, error detecting unit detecting data error, error correcting unit correcting data error, and host device The error detection unit detects an error in the read data using the check code, and after the error correction corrected by the error correction unit. And when the error detecting unit detects an error in the read data, the error correcting unit detects When the error detecting unit detects no error in the read data, the sending unit sends the data to a host device, and the error detecting unit When no error in the corrected data is detected, the fact that the error has been corrected together with the data after error correction is sent to the host device, while the error detection unit detects an error in the data after error correction. If the data is abnormal, the fact that the data is abnormal is sent to the host device.

  The host device is, for example, a personal computer or a PLC that instructs the read / write processing device to read and write data of the RFID tag.

  According to the read / write processing device of the present invention, when data is written, the data and the corresponding check code are written in the RFID tag memory, and when the data is read, the read check code is used to check for errors in the read data. If an error is detected, error correction is performed. Further, an error in the corrected data is detected, and when an error in the corrected data is detected, the fact that the data is abnormal is sent to the host device. However, when no error in the corrected data is detected, the fact that the data error has been corrected is sent to the host device together with the corrected data, so that the user can use the RFID tag through the host device. If there is an abnormality in the read data, the abnormal data was restored to the correct data by error correction, or error correction Therefore it becomes possible to grasp that that could not be restored to the correct data.

  Therefore, the user can take measures such as exchanging the RFID tag or changing the use environment when abnormality occurs in the data and correct data is restored by error correction.

  (5) In one embodiment of the read / write processing device of the present invention, the check code is a CRC check code and an ECC check code, the error detection unit detects an error by CRC, and the error correction unit includes: The error of 1-bit data is corrected by ECC.

  In the RFID tag, the memory corruption usually starts with 1-bit data corruption. According to this embodiment, the ECC-corrected 1-bit data can be corrected to restore correct data.

  In addition, since error detection is performed on CRC after error correction by ECC, which has a higher detection rate of error detection than ECC, if there is an error in data after error correction, it is performed with high accuracy. Can be detected, so that it becomes highly reliable.

  Furthermore, since error detection by CRC is performed before error correction by ECC, it is not necessary to perform error correction by ECC unnecessarily for normal data occupying most of the processing, and the processing speed is improved. Can do.

  (6) In the embodiment of the above (5), the memory of the RFID tag has a user area, a plurality of mirror areas, and a check code area, and the same data to be written from the transmitter is the user And the check code is written to the check code area, and the sending unit detects data error after error correction by the error detection unit. Is not sent to the host device, and when the error detection unit detects an error in the data after error correction, the data read from the user area and the plurality of mirrors A majority decision matching unit that creates new data by majority decision for each bit based on mirror data read from each area is further provided. The error detection unit detects an error in the data created by the majority match unit, and the sending unit, together with the created data, when the error detection unit detects no error in the created data The fact that the error has been corrected is sent to the host device, and when the error detection unit detects an error in the created data, the fact that the data is abnormal is sent to the host device.

  According to this embodiment, using the mirror data read from the plurality of mirror areas, the data error is corrected by the majority match for each bit to create new data. Since the error can be corrected by CRC for new data as well, if there is an error in the created new data, it can be notified to the host device. It will be expensive.

  (7) In the embodiment of the above (6), the sending unit does not send the fact that the data is abnormal to the host device when the error detecting unit detects an error in the created data. The error correction unit corrects an error in the data when the error detection unit detects an error in the created data, and the error detection unit corrects the error after correction corrected by the error correction unit. An error in the created data is detected, and the sending unit corrects the error together with the created data after the correction when the error detecting unit does not detect an error in the created data after the correction. When the error detection unit detects an error in the created data after correction, the fact that the data is abnormal is sent to the host device.

  According to this embodiment, when there is an error in the new data created by the majority match, the error is corrected by the ECC, and the error is also detected by the CRC for the corrected new data. If there is an error in the new data, it can be notified to the host device, so that the reliability is high.

  (8) An RFID tag according to the present invention is an RFID tag that has a memory for storing data, and wirelessly transmits data to and from a read / write processing device. A writing unit for writing a code, a reading unit for reading data and a corresponding check code from the memory, an error detecting unit for detecting an error in the data, an error correcting unit for correcting an error in the data, and the read / write processing device A transmission unit for transmitting data, wherein the error detection unit detects an error in the read data using the check code, while an error in the data after error correction corrected by the error correction unit is detected. The error correction unit corrects the data error when the error detection unit detects an error in the read data. When the error detection unit does not detect an error in the read data, the transmission unit transmits the data to the read / write processing device, and the error detection unit detects an error in the data after error correction. If not, the error correction data is transmitted together with the corrected data to the read / write processing device. On the other hand, when the error detection unit detects an error in the corrected data, the data is abnormal. This is transmitted to the read / write processing device.

  According to the RFID tag of the present invention, when data is written, the data and the corresponding check code are written in the RFID tag memory, and when the data is read, the read check code is used to detect an error in the read data. If an error is detected, error correction is performed, and further, an error in the corrected data is detected. When an error in the corrected data is detected, the fact that the data is abnormal is sent to the read / write processor. However, when no error in the corrected data is detected, the correction of the data error is performed together with the corrected data in the read / write processing device, so that the user can use the RFID tag through the read / write processing device. If there is an error in the read data, correct data was restored by error correction, or error correction Therefore, the correct data will be able to grasp that that could not be restored.

  Therefore, the user can take measures such as exchanging the RFID tag or changing the use environment when abnormality occurs in the data and correct data is restored by error correction.

  (9) In one embodiment of the RFID tag of the present invention, the check code is a CRC check code and an ECC check code, the error detection unit detects an error by CRC, and the error correction unit is an ECC. This corrects an error in 1-bit data.

  In the RFID tag, the memory corruption usually starts with 1-bit data corruption. According to this embodiment, the ECC-corrected 1-bit data can be corrected to restore correct data.

  In addition, since error detection is performed on CRC after error correction by ECC, which has a higher error detection rate than ECC, if there is an error in the data after error correction, the error is detected with high accuracy. Can be detected.

  Furthermore, since error detection by CRC is performed before error correction by ECC, it is not necessary to perform error correction by ECC unnecessarily for normal data occupying most of the processing, and the processing speed is improved. Can do.

 (10) In the embodiment of the above (9), the memory has a user area, a plurality of mirror areas, and a check code area, and the writing unit stores the same data in the user area and the plurality of mirror areas. And the check code is written to the check code area, and when the error detection unit detects an error in the data after error correction, the transmitter detects that the data is abnormal. Data is read from the user area and read from the plurality of mirror areas when an error in the data after error correction is detected by the error detection unit without being transmitted to the read / write processing device. A majority decision matching unit that creates new data based on a majority decision for each bit based on mirror data; and the error detection unit includes: Detecting an error in the data created by the majority decision matching unit, and when the error detection unit detects no error in the created data, the transmitting unit corrects the error together with the created data. The data is transmitted to the read / write processor, and when the error detection unit detects an error in the created data, the fact that the data is abnormal is transmitted to the read / write processor.

  According to this embodiment, using the mirror data read from the plurality of mirror areas, the data error is corrected by the majority match for each bit to create new data. Since the error can be corrected by CRC for new data as well, if there is an error in the created new data, it can be notified to the read / write processing device. Will be expensive.

 (11) In the embodiment of (10), when the error detection unit detects an error in the created data, the transmission unit transmits to the read / write processing device that the data is abnormal. The error correction unit corrects a data error when the error detection unit detects an error in the created data, and the error detection unit corrects the error after the correction is performed by the error correction unit. When the error is not detected in the corrected data by the error detecting unit, the sending unit detects an error together with the generated data after the correction. The correction is transmitted to the read / write processing device, and when the error detection unit detects an error in the created data after correction, the read / write processing device indicates that the data is abnormal. It is intended to be sent.

  According to this embodiment, when there is an error in the new data created by the majority match, the error is corrected by the ECC, and the error is also detected by the CRC for the corrected new data. If there is an error in the new data, it can be notified to the read / write processing device, so that the reliability is high.

  According to the present invention, when an abnormality such as memory corruption occurs in data read from the RFID tag, and the correct data is restored by error correction of the data, the user can grasp that, It becomes possible to take measures such as replacing the RFID tag or changing the use environment, and the usability is improved as compared with the conventional example in which only abnormal data can be obtained suddenly on a certain day.

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

(Embodiment 1)
FIG. 1 is a configuration diagram of an RFID system. This RFID system includes a host device such as a personal computer 1 and a PLC, a read / write processing device (reader / writer) 2 for an RFID tag according to the present invention, and an antenna for transmission and reception. 3 and an RFID tag 4.

  The personal computer 1 which is a host device and the read / write processing device 2 are connected by a serial communication cable 5 or a USB cable. The personal computer 1 transmits a command for reading data of the RFID tag 4 and a command for writing to the read / write processing device 2 and receives a processing result from the read / write processing device 2.

  The read / write processing device 2 and the antenna 3 are connected by a cable 6, and the antenna 3 and the RFID tag 4 are wirelessly connected. The read / write processing device 2 reads and writes data from the RFID tag 4.

  FIG. 2 is a block diagram of the read / write processing device 2 and the RFID tag 4.

  The read / write processing device 2 includes a control unit 7, a transmission unit 8, a reception unit 9, a display unit 10, an interface (I / F) circuit 11, and the like, and is configured to be incorporated in one housing.

  The control unit 7 of the read / write processing device 2 is constituted by a microcomputer, and based on a program incorporated in the internal memory, communication processing with the RFID tag 4, error detection, error correction processing described later, and personal computer 1 Communication processing is executed. In addition, the control unit 7 outputs a high-frequency pulse that is a source of a carrier wave based on a pulse signal from an oscillation circuit (not shown). Further, when communicating with the RFID tag 4, data representing the contents of the command is output as a pulse signal (command signal).

  The transmission unit 8 and the reception unit 9 are each provided with a modulation circuit and a demodulation circuit.

  The interface circuit 11 is used for communication with a host device such as the personal computer 1.

  The read / write processing device 2 receives commands for writing to and reading from the memory of the RFID tag 4 from a host device such as the personal computer 1 and sends the command to the RFID tag 4 via the antenna 3 according to the type of the received command. Write data and read data.

  On the other hand, the RFID tag 4 is of a type that does not have a built-in power supply and operates by induced electromotive force generated by a transmission wave from the read / write processing device 2, and includes an antenna 12, a control circuit 13, and a memory 14. The control circuit 13 includes a control logic circuit or microcomputer, a modulation circuit, a demodulation circuit, and the like.

  In the RFID tag 4, for example, a user stores various types of information at a manufacturing site. Since important data is stored in the memory 14 of the RFID tag 4, there is a possibility that a serious trouble occurs when the data is destroyed.

  In this embodiment, the read / write processing device 2 performs a destructive inspection and error correction of the memory of the RFID tag 4 so that the occurrence of such trouble can be suppressed.

  In other words, the read / write processing device 2 allows the user to recognize when the data of the RFID tag 4 is garbled for some reason and to obtain the restored correct data.

  3 and 4 are flowcharts for explaining the operation of the read / write processing device 2. FIG. 3 shows an operation when data is written to the RFID tag 4, and FIG. 4 shows a time when data is read from the RFID tag 4. The operation of each is shown.

  When writing data to the RFID tag 4, as shown in FIG. 3, a write command for writing user data designated by the user to a designated address in the memory is transmitted to the RFID tag 4 (step n1). Further, user data to be written is transmitted (step n2), and a check code of the user data calculated internally is transmitted (step n3).

  In this embodiment, a calculation result of CRC 2 bytes and ECC 3 bytes is used as a check code for user data of a specified number of bytes.

  The RFID tag 4 receives a write command, user data, and check code from the read / write processing device 2 and writes the user data and check code to a specified address in the memory 14.

  FIG. 5 is a memory map of the RFID tag 4. As shown in FIG. 5, for the user data of the specified number of bytes from the address specified by the user, the check code from the address next to the end address of the data As described above, calculation results of CRC 2 bytes and ECC 3 bytes are written.

  Note that the CRC calculation range in the read / write processing device 2 is only user data, and the ECC calculation range is user data and CRC data.

  Next, when reading data from the RFID tag 4, the read / write processing device 2 sends the user data and the 5-byte check code for the specified number of bytes from the specified address to the RFID tag 4 as shown in FIG. 4. A read command for reading is transmitted (step n1).

  The RFID tag 4 that has received the read command reads the specified user data and check code from the memory 14 and transmits them to the read / write processing device 2.

  As shown in FIG. 4, the read / write processing device 2 receives user data read from the RFID tag 4 and transmitted (step n2) and also receives a corresponding check code (step n3).

  Next, a CRC check is performed on the read user data (step n4). In this CRC check, the read user data is calculated according to a known CRC calculation logic, and the calculation result is compared with the CRC calculation result read from the RFID tag 4. Judge that the data is normal.

  In step n5, it is determined whether or not the CRC test result is normal. If the CRC test result is normal, the user data is sent to the personal computer 1 which is the host device, and the process ends normally.

  If the inspection result is abnormal in step n5, 1-bit error correction of user data and CRC data is performed by a known ECC logic (step n6).

  Next, it is determined whether or not the error correction of the 1-bit data has been performed (step n7). If the error cannot be corrected, the fact that the read user data is abnormal and could not be corrected indicates that the personal device, which is the host device. Send to computer 1 and end abnormally.

The error detection rate of ECC is lower than the error detection rate of CRC, and even if an error cannot be detected by ECC, an error may be detected by CRC. For example,
In ECC, when a 2-bit error occurs, it can be detected that correction is impossible, but if a 3-bit error occurs, it may be erroneously detected that the 1-bit error has been correctly corrected.

  Therefore, when error correction of 1-bit data is completed in step n7, CRC check of user data after error correction is performed again (step n8).

  It is determined whether or not the CRC check result is normal (step n9). When the CRC check result is normal, the fact that the error correction has been performed is sent to the personal computer 1 as the host device together with the user data after the error correction. And terminate normally.

  In step n9, if the inspection result is abnormal, the fact that the read user data is abnormal and cannot be corrected is sent to the personal computer 1 which is the host device to end abnormally.

  The personal computer 1 can display the data from the read / write processing device 2 and can read the data correctly without performing error correction, or can restore the correct data by error correction even though the data could not be read correctly. Alternatively, it is possible to display that data could not be read correctly and error correction could not be performed.

  In general, in the RFID tag 4, since the memory corruption usually starts with 1-bit data corruption, the data can be restored by error correction of 1-bit data by ECC. When correct data is restored by error correction of the data, it can be recognized, so that the RFID tag 4 can be replaced or the use environment can be changed using the period during which the correct data is restored. It is possible to take measures such as changing the memory so that it will not be garbled. Therefore, reliability and usability are improved as compared with the conventional example in which only abnormal data can be obtained suddenly on a certain day.

  In addition, in ECC, there is a risk of erroneous detection as described above. However, since data that has been restored by performing error correction is subjected to error detection again by CRC having a higher error detection rate than ECC, the restored data Whether or not is correct can be determined with high accuracy, and the reliability is high.

  Further, since error detection by CRC is performed before ECC, it is not necessary to perform error correction by ECC unnecessarily for normal data occupying most of the processing, and the processing speed can be improved.

  In addition, since the ECC calculation range includes not only user data but also CRC data, the error detection determination area can be extended.

(Embodiment 2)
In the above-described embodiment, an error in 1-bit data is corrected. However, in this embodiment, an error in 2-bit or more data can be corrected.

  FIG. 6 is a memory map of the RFID tag 4 of this embodiment.

  In this embodiment, the storage area of the memory 14 of the RFID tag 4 is divided into a user area, a first mirror area, a second mirror area, and a check code area. In this example, one page includes It has an 8-byte configuration, and performs writing and reading in page units.

  When writing data to the memory 14 of the RFID tag 4, user data for a specified number of bytes from the address specified by the user is written to the user area, and the same user data is written to the first and second mirror areas. Each is written, and a corresponding check code is written in the check code area.

  In the above-described embodiment, a check code of CRC 2 bytes and ECC 3 bytes is written following the user data. Therefore, the user needs to manage so that user data is not written in the check code area. In this embodiment, since the mirror data and the check code are written in dedicated areas, the user need not consider any data other than the user data.

  In FIG. 6, since one page has an 8-byte configuration, for example, when the user data is used from address 000E to address 0019, the user area is the user area 000E to 0019, the first mirror. The area is 200E to 2019, the second mirror area is 400E to 4019, and the check code area is 6008 to 601F.

  The check code 1-1 is a check code of 0008 to 000F, the check code 1-2 is a check code of 0010 to 0017, and the check code 1-3 is a check code of 0018 to 001F.

  Next, the reading operation of this embodiment will be described with reference to FIG.

  First, a read command for reading the user data and the corresponding check code for the specified number of bytes from the specified address is transmitted to the RFID tag 4 (step n1), and read and transmitted from the RFID tag 4. User data (step n2) and a corresponding check code (step n3).

  Next, in the process of FIG. 4 described above, the inspection process A surrounded by a broken line is executed (steps n4 to n9).

  That is, as shown in FIG. 4, a CRC check is performed on the user data (step n4), and it is determined whether or not the check result is normal (step n5). The data is sent to a personal computer 1 and the process ends normally.

  When the inspection result is abnormal, 1-bit error correction of user data and CRC data is performed (step n6), and it is determined whether or not error correction has been performed (step n7). The CRC check of the corrected user data is performed again (step n8), and it is determined whether or not the CRC check result is normal (step n9). When the CRC check result is normal, the error correction is performed together with the user data after error correction. Is sent to the personal computer 1, which is the host device, and the process ends normally.

  When error correction cannot be performed in step n7, or when the inspection result is abnormal in step n9, that is, when it is determined that the process has ended abnormally, the process proceeds to step n10 in FIG.

  In step n10 in FIG. 7, a read command for reading the first and second mirror data in the first and second mirror areas corresponding to the user data is transmitted to the RFID tag 4 and read from the RFID tag 4. The transmitted mirror data of the first and second mirror areas is received (step n11).

  Next, a majority check is performed in bit units based on the user data that has already been read and the first and second mirror data in the corresponding first and second mirror areas to create new user data (step n12). ). In other words, the data obtained by voting the user data, the first mirror data, and the second mirror data in the corresponding bit unit is used as new user data.

  In this way, the user data and the first and second mirror data are used to correct the error and create new user data by the majority match in bit units, so that the error of data of 2 bits or more is also corrected. can do.

  Next, in order to improve the reliability, the same inspection process A as in FIG. 4 is executed on the new user data.

  That is, as shown in FIG. 4, a CRC check of new user data is performed (step n4), and it is determined whether or not the check result is normal (step n5). The data is sent to the personal computer 1 which is a device, and the fact that error correction has been performed is sent and the process ends normally.

  When the inspection result is abnormal, 1-bit error correction of new user data and CRC data is performed (step n6), it is determined whether or not error correction has been performed (step n7). CRC check of the new user data after error correction is performed again (step n8), and it is determined whether or not the CRC check result is normal (step n9). The fact that the error correction has been performed is sent to the personal computer 1 which is the host device, and the process ends normally.

  When error correction could not be performed in step n7, or when the test result was abnormal in step n9, that is, when it was determined that the process ended abnormally, the read user data was abnormal and could not be corrected. A message to that effect is sent to the personal computer 1, which is the host device, and the process ends abnormally.

  In this embodiment, when a CRC check of new user data is performed and the inspection result is abnormal, 1-bit error correction is performed. However, as another embodiment of the present invention, the inspection result is abnormal. In some cases, the fact that the data is abnormal and could not be corrected without performing 1-bit error correction may be sent to the personal computer 1, which is the host device, to terminate abnormally.

  In the above-described embodiment, writing / reading is performed in units of pages. However, as another embodiment of the present invention, writing / reading may be performed in units of user data as shown in FIG.

(Embodiment 3)
In each of the above-described embodiments, error detection and error correction are performed by the read / write processing device 2, but as another embodiment of the present invention, the read / write processing device 2 does not perform error detection and error correction, and does not perform error detection and error correction. In step 4, error detection and error correction may be performed.

  FIG. 9 and FIG. 10 are flowcharts for explaining the operation when error detection and error correction are performed by the RFID tag 4. FIG. 9 shows the operation at the time of writing to the RFID tag 4, and FIG. FIG. 5 is a diagram corresponding to FIG. 3 and FIG. 4 described above, respectively.

  At the time of data writing, as shown in FIG. 9, user data to be written from the read / write processing device 2 is written to a specified address in the memory 14 (step n1), and the check code of the user data calculated internally is used. A certain CRC2 byte and ECC3 byte are written (step n2).

  Next, at the time of data reading, as shown in FIG. 10, user data and a 5-byte check code for the specified number of bytes are read from the memory 14 (steps n1 and n2), and a CRC check of the user data is performed (step n3 ). In step n4, it is determined whether or not the CRC check result is normal. When the CRC check result is normal, the user data is transmitted to the read / write processing device 2 to complete the normal end.

  If the inspection result is abnormal in step n4, 1-bit error correction of user data and CRC data is performed by ECC (step n5).

  Next, it is determined whether or not the 1-bit data has been corrected (step n6). If the 1-bit data cannot be corrected, the read / write processing device 2 is informed that the read user data is abnormal and cannot be corrected. Send and terminate abnormally.

  If error correction of 1-bit data has been completed in step n6, CRC check of user data after error correction is performed again (step n7).

  It is determined whether or not the CRC check result is normal (step n8). When the CRC check result is normal, the fact that error correction has been performed is transmitted to the read / write processing device 2 together with the user data after error correction, and the processing ends normally. And

  In step n8, when the inspection result is abnormal, the fact that the read user data is abnormal and cannot be corrected is transmitted to the read / write processing device 2 to end abnormally.

  Of course, the RFID tag 4 may perform the same processing as in FIG.

  The present invention is useful for RFID systems and the like.

It is a figure which shows the structure of the RFID system which concerns on one embodiment of this invention. FIG. 2 is a block diagram of the read / write processing device and RFID tag of FIG. 1. It is a flowchart with which it uses for description of operation | movement at the time of writing. It is a flowchart with which it uses for description of operation | movement at the time of read-out. It is a memory map of an RFID tag. It is a memory map of the RFID tag of other embodiment of this invention. It is a flowchart with which it uses for description of operation | movement at the time of read-out. It is a figure which shows the other example of the memory map of a RFID tag. It is a flowchart with which it uses for description of operation | movement at the time of writing of the RFID tag which concerns on this invention. It is a flowchart with which it uses for operation | movement description at the time of reading of the RFID tag which concerns on this invention.

Explanation of symbols

1 Personal Computer 2 Read / Write Processing Device (Reader / Writer)
3 Antenna 4 RFID tag 7 Control unit 8 Transmitting unit 9 Receiving unit

Claims (11)

A read / write processing method for reading and writing data to a memory of an RFID tag,
A writing step of writing data and a corresponding check code into the memory;
A reading step of reading data and corresponding check codes from the memory;
A first error detection step for detecting an error in data read from the memory using a check code read from the memory;
An error correction step for correcting an error in the data when an error in the data is detected in the first error detection step;
A second error detection step of detecting an error in the data after error correction corrected in the error correction step;
When an error in the data after error correction is detected in the second error detection step, the data is abnormal. When no error in the data after error correction is detected, the error is corrected. A notification step for notifying
A read / write processing method comprising: The check code is a CRC check code and an ECC check code,
In the first and second error detection steps, an error is detected by CRC;
The read / write processing method according to claim 1, wherein in the error correction step, an error of 1-bit data is corrected by ECC. The memory has a user area and a plurality of mirror areas,
In the writing step, the same data is written to the user area and the plurality of mirror areas,
The notification step is a first notification step. In the first notification step, when an error in data after error correction is detected in the second error detection step, it is notified that the data is abnormal. Without
Based on the data read from the user area and the mirror data respectively read from the plurality of mirror areas when an error in the data after error correction is detected in the second error detection step. A step of creating new data by the majority match for each bit,
A third error detection step for detecting an error in the created new data;
If an error in the new data is detected in the third error detection step, the data is abnormal. If no error in the new data is detected, the error is corrected. A second notification step to notify;
The read / write processing method according to claim 2, further comprising: A read / write processing device that reads and writes data to and from an RFID tag in a contactless manner,
A transmitter that transmits data to be written to the RFID tag and a corresponding check code to the RFID tag;
A receiving unit for receiving data read from the RFID tag and a corresponding check code;
An error detector for detecting data errors;
An error correction unit for correcting data errors;
A sending unit for sending data to the host device,
The error detection unit detects an error in the read data using the check code, while detecting an error in the data after error correction corrected by the error correction unit,
The error correction unit corrects an error in the data when the error detection unit detects an error in the read data;
The sending unit sends the data to a host device when the error detecting unit does not detect an error in the read data, and the error detecting unit detects an error in the data after error correction. If not, the fact that the error has been corrected together with the data after error correction is sent to the higher-level device. On the other hand, when the error detection unit detects an error in the data after error correction, the data is abnormal. Is sent to the host device. The check code is a CRC check code and an ECC check code,
The error detection unit detects an error by CRC,
The read / write processing device according to claim 4, wherein the error correction unit corrects an error of 1-bit data by ECC. The RFID tag memory has a user area, a plurality of mirror areas and a check code area, and the same data to be written from the transmission unit is written to the user area and the plurality of mirror areas, respectively. The check code is written in the check code area;
When the error detection unit detects an error in the data after error correction, the sending unit does not send the fact that the data is abnormal to the host device,
When an error in data after error correction is detected by the error detection unit, a bit is determined based on the data read from the user area and the mirror data read from the plurality of mirror areas, respectively. It further includes a majority decision matching unit that creates new data by majority match for each.
The error detection unit detects an error in the data created by the majority match unit,
When the error detecting unit does not detect an error in the created data, the sending unit sends out to the host device that the error has been corrected together with the created data, and the error detecting unit 6. The read / write processing device according to claim 5, wherein when a data error is detected, the fact that the data is abnormal is transmitted to the host device. When the error detecting unit detects an error in the created data, the sending unit does not send the fact that the data is abnormal to the host device,
The error correction unit corrects a data error when the error detection unit detects an error in the created data,
The error detection unit detects an error in the created data after correction corrected by the error correction unit,
When the error detection unit does not detect an error in the created data after the correction, the sending unit sends the fact that the error is corrected together with the created data after the correction to the host device, The read / write processing device according to claim 6, wherein when the error detection unit detects an error in the created data after correction, the read / write processing device transmits that the data is abnormal to the host device. An RFID tag having a memory for storing data and wirelessly transmitting data to and from a read / write processing device,
A writing unit for writing data and a corresponding check code in the memory;
A reading unit for reading data and a corresponding check code from the memory;
An error detector for detecting data errors;
An error correction unit for correcting data errors;
A transmission unit for transmitting data to the read / write processing device,
The error detection unit detects an error in the read data using the check code, while detecting an error in the data after error correction corrected by the error correction unit,
The error correction unit corrects a data error when the error detection unit detects an error in the read data;
When the error detection unit does not detect an error in the read data, the transmission unit transmits the data to the read / write processing device, and the error detection unit detects an error in the data after error correction. If not, the error correction data is transmitted to the read / write processing device together with the error corrected data. An RFID tag that transmits a message to the read / write processing device. The check code is a CRC check code and an ECC check code,
The error detection unit detects an error by CRC,
The RFID tag according to claim 8, wherein the error correction unit corrects an error of 1-bit data by ECC. The memory has a user area, a plurality of mirror areas and a check code area,
The writing unit writes the same data to the user area and a plurality of mirror areas, and writes the check code to the check code area.
When the error detection unit detects an error in the data after error correction, the transmission unit does not transmit that the data is abnormal to the read / write processing device,
When an error in data after error correction is detected by the error detection unit, a bit is determined based on the data read from the user area and the mirror data read from the plurality of mirror areas, respectively. It further comprises a majority decision matching unit that creates new data by majority decision for each.
The error detection unit detects an error in the data created by the majority match unit;
When the error detection unit does not detect an error in the created data, the transmission unit transmits an error correction together with the created data to the read / write processing device, and the error detection unit The RFID tag according to claim 9, wherein when an error in the created data is detected, the fact that the data is abnormal is transmitted to the read / write processing device. When the error detection unit detects an error in the created data, the transmission unit does not transmit that the data is abnormal to the read / write processing device,
The error correction unit corrects a data error when the error detection unit detects an error in the created data,
The error detection unit detects an error in the created data after correction corrected by the error correction unit,
When the error detection unit does not detect an error in the created data after the correction, the sending unit transmits to the read / write processing device that the error is corrected together with the created data after the correction. The RFID tag according to claim 10, wherein when the error detection unit detects an error in the created data after correction, the RFID tag transmits to the read / write processing device that the data is abnormal.

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