JP2001331382A - Method and device for managing nonvolatile memory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for managing a nonvolatile memory, which can be used continuously by reading out normal stored data and recovering a write error, even if error occurs because power source is turned off when updating data or the like. SOLUTION: User data are written in a user data area (702) and in the case of a write success (703), a user data array shown by user data array reference information is read out (704). Then, the written data are collated with the read data by executing validity confirmation information arithmetic write processing (705). When these data are agree (706), it is decided whether write of user data to the user data array by the number of array reference information (708) is completed. If the answer is a 'No', '1' is added to (i) and processing is executed again from user data area write processing (702). When the data do not agree in the validity decision (706) of the user data, error recovery is performed by changing the data to a new user data array, and the nonvolatile memory is continuously used by re-executing processing from the write (702) into the user data area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method and an apparatus for managing a nonvolatile memory which improve the reliability against data errors when writing to the nonvolatile memory.

[0002]

2. Description of the Related Art Conventionally, in a system equipped with a microprocessor, when the power is turned off and the system is restarted, the previously used data must be continuously used. A RAM to which a memory backup circuit has been added has been widely used as a nonvolatile memory.

A method of realizing a nonvolatile memory using such a memory backup circuit using a battery and a volatile RAM can be realized relatively easily. A non-volatile memory using the above-mentioned RAM is used as a main memory of the system, and an address of the RAM is divided into a volatile memory area and a non-volatile memory area and managed, so that one device can be used as a volatile memory and a non-volatile memory. It can be said that this is an excellent use method in terms of cost performance. However, if the battery voltage drops, the stored data is lost, so it was necessary to pay close attention to the drop in the battery voltage used for backup.

On the other hand, there is a method of realizing a nonvolatile memory using a nonvolatile memory device which does not require a memory backup circuit using a battery. This is mainly FLASH-RO
By using the M or EEPROM, data can be stored for a long period of time without data backup by a battery. However, compared to a volatile memory such as a static RAM, a certain amount of time is required for the writing process. When a power failure or the like occurs, a write error may occur. In addition, there is a lifetime in the number of times of writing of a memory device, and in a system that performs frequent writing, an error may occur when writing data.

Conventionally, as a memory control method of this kind, a memory control method described in Japanese Patent Application Laid-Open No. Hei 8-138039 and FIG. 9 has been known. That is, in the method of reproducing data from the memory card shown in FIG.
Select one of the recorded storage units 901
Then, the order information of the start storage area of the storage unit selected by referring to the storage unit attribute table is read out 902, and the use information corresponding to the read order is read out by referring to the storage area table, and the next storage is performed. According to a method of reading out the order of the areas, processes 903 to 905 of continuing reading until the reading end information of the selected storage unit is read out are executed.
A data reading process 906 from the corresponding storage area of the data area is executed according to the read order of the read storage area order information. According to this memory control method, a reading check is performed for a writing error during a recording process of a memory card using a nonvolatile memory.

With this memory control method, when an error is detected during recording, another block is allocated and rewriting is performed, so that data is not lost during recording. However, this method cannot detect an error at the time of reproduction and cannot repair the error.

[0007]

However, in the above-mentioned conventional memory technology, a method of detecting data errors by adding checksum data of the write data together with data to be written to the nonvolatile memory has been put to practical use. ,
In this case, the user is notified that an error has been detected to prompt the user to repair the system, or the operation of the system is continued using the initial setting value prepared in advance. In other words, there is a system that checks the presence or absence of an error and notifies the user by recording the data for error detection such as a checksum together with the write data, but the error is corrected and repaired and the system is continued. There was a problem that it could not be used.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. In a system using a nonvolatile memory such as an EEPROM, a writing failure due to a power supply cutoff at the time of updating data, a device failure, or a writing error occurs. Even if a write error occurs due to a cause such as a service life, a normal storage data can be read out, and further, the error can be recovered and the nonvolatile memory management method and the management device can be used so that the nonvolatile memory can be used continuously. To provide.

[0009]

According to the present invention, there is provided a nonvolatile memory management method comprising the steps of dividing an entire data area of a nonvolatile memory for storing user data into a rewrite-permitted data area and a rewrite-inhibited data area; The rewrite-permitted data area stores data whose contents are to be changed, and the rewrite-prohibited data area stores data whose contents are not to be changed. With this configuration, when storing data in a non-volatile memory such as an EEPROM mounted on hardware of a system using a microprocessor, the type of additional data necessary for error recovery depends on the nature of the stored data. By providing a data array structure for error recovery only for data to be divided and rewritten, the amount of use of the nonvolatile memory can be reduced and data management can be facilitated.

In the method of managing a nonvolatile memory according to the present invention, the rewrite permission data area is constituted by a plurality of user data arrays each having an array element, and the user data array includes a user data area and validity check information storage. An area and a management information area having a write error occurrence count storage area, wherein the user data area stores data to be used arbitrarily, and the validity check information storage area stores the validity of the contents of the user data area. , And the write error occurrence count storage area stores the number of write error occurrences for the same data area. With this configuration, the user data to be rewritten, which is stored in the non-volatile memory, the checksum data for confirming the validity of the contents, and the number of times the write error has been detected are grouped into one set, and this data group is By storing a plurality of array elements in the user data array, it is possible to easily detect data causing a data error in the user data array and provide a data rescue means of reading data of another user data array when a data error is detected. In addition, by improving the reliability of user data stored in the non-volatile memory, detecting the area of the user data array where data errors frequently occur, and replacing the area of the user data array, data loss due to the data error can be prevented. Possibility can be reduced.

In the nonvolatile memory management method according to the present invention, a plurality of user data array reference information are provided in the rewrite permission data area, and designation information indicating each user data array in the user data array area is not overlapped. Is recorded in the user data array reference information corresponding to. With this configuration, the user data array that is currently in use by using a plurality of pointers that store user data array reference information such as addresses or numbers pointing to each user data array to refer to a plurality of user data arrays that store array elements , And the user data array disabled by the error detection can be managed so as not to be reused.

In the method of managing a nonvolatile memory according to the present invention, the validity of the contents of the user data array pointed to by the user data array reference information is determined, and if the validity cannot be confirmed, another user data array is determined. The configuration is such that the validity of the contents of the array element of the user data array indicated by the reference information is determined, and control is performed to output the data of the user data array for which the validity has been confirmed. With this configuration, the validity of the data of the currently used user data array is verified, and a control method when a data error is detected is provided. The error is detected for one of the plurality of user data arrays. Even in this case, when the validity of the data of the other user data array can be confirmed, by outputting the data, even if an error is detected, normal user data can be obtained and the device can be returned to the normal state. Can be operated continuously.

According to the nonvolatile memory management method of the present invention, the validity of the user data array indicated by the user data array reference information is determined, and if the validity cannot be confirmed, writing to the user data array is performed. Or, when the read function is verified and the write or read function for the verified user data array is determined to be normal, the user data array is continuously used, and the write or read function is determined to be defective. Has a configuration in which the user data array reference information indicating the user data array is updated, and error recovery processing is performed so as to use the user data array indicated by the updated user data array reference information. With this configuration, in a recovery process when an error is detected in the data of the user data array, a test pattern write and read test is performed on the corresponding user data array to determine whether the data can be reused. If so, the control is shifted to the next available user data array, and the necessary user data array can be secured.

In the nonvolatile memory management method according to the present invention, the user data array reference information is completely initialized or initialized to ascending or descending user data array designation information which does not overlap at the time of factory shipment, respectively. At the time of recovery after detecting an error that cannot be rewritten, in the case of ascending order, update the specified information next to the largest specified information among the currently used specified information, and in the case of descending order, use the currently used information. It is configured to update the specified information next to the smallest specified information among the plurality of specified information. According to this configuration, when an error is detected in the user data array, an algorithm for determining the next usable user data array can be determined by a simple method without adding excessive additional information to each user data array. Can be determined and managed.

In the method of managing a nonvolatile memory according to the present invention, when the designation information of the user data array reference information is initialized in accordance with the order of the corresponding user data array, and the power supply is restored after the power is turned off during the write operation, By determining the content of the user data array indicated by the user data array reference information and the corresponding validity check information, the user data array that was being updated at the moment when the power was turned off during the write operation was specified, It has a configuration to perform error recovery processing. According to this configuration, it is possible to identify the user data array that was being written when the power supply was lost after the power supply was restored after the power supply was restored after the power supply was restored during the write update of the nonvolatile memory. It is possible to determine whether to make the update valid or to restore the previous state, and at the same time, to restore the user data array in the state of being written.

In the method of managing a nonvolatile memory according to the present invention, the function verification of the nonvolatile memory is performed every time the validity of the currently used user data array indicated by the user data array reference information is not obtained. In the case where the error occurrence detection number information of the user data array is updated and the function verification for the same user data array is performed a predetermined number of times or more, the user data array reference information indicating the currently used user data array is changed. Then, a new user data array corresponding thereto is used. With this configuration, when an error is detected in a specific user data array, an algorithm for determining whether or not to reuse the user data array is implemented. When the number of times of execution of the read test exceeds a predetermined number, it is determined that the reliability of the user data array is degraded, the use of the user data array is stopped, and the user data is transferred to another user data array. By storing, the reliability of the data content can be improved.

A nonvolatile memory management device according to the present invention comprises: a nonvolatile memory for storing user data; and control means for controlling reading and writing of data to and from the nonvolatile memory. Executing the method of managing a nonvolatile memory according to any one of claims 1 to 8 for a non-volatile memory, and, when a data error is detected during operation, avoids the data error and continues normal operation. It has a configuration. With this configuration, even when a data error is detected in the non-volatile memory, the operation can be continued as in the normal state, and the reliability of the data stored in the non-volatile memory can be improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
The first to seventh embodiments of the present invention will be described in detail. (First Embodiment) First, a management method and a management device for a nonvolatile memory according to a first embodiment of the present invention will be described with reference to FIG. A non-volatile memory management device (information processing device) illustrated in FIG. 1 includes a microprocessor (CPU) 101 that controls the entire device, a RAM 102 that stores data necessary for executing a program, a ROM 103 that stores a program and the like, A non-volatile memory 104 for storing data requiring non-volatility, an input interface 105 for interfacing input data,
Information input means 106 for inputting data, output interface 107 for interfacing output data, information output means 108 for outputting data, data bus 109
It is composed of

Next, the overall operation of the nonvolatile memory management device as an information processing device according to the first embodiment of the present invention will be described with reference to FIG. This nonvolatile memory management device is performed under the control of the microprocessor 101. That is, when the power is turned on, the reset of the microprocessor 101 is released, and the microprocessor 101 executes an application program stored in the ROM 103 connected via the data bus 109. The data area required for execution is
M102, and a non-volatile memory 104 such as an EEPROM is used for recording and reproducing user data required when executing the application program. When the application program is executed, information input from the information input unit 106 connected via the input interface 105 is processed, and a processing result is output from the information output unit 108 connected via the output interface 107.

Next, referring to FIG.
The memory map No. 04 will be described. Non-volatile memory 104
Is divided into two areas on the memory map, and the data to be stored is stored in each area according to its use. Data that is set at the time of shipment from the factory and is not changed by the user after shipment, such as a system-specific number, system adjustment data, and initial values of information set by the user, are stored in the rewrite-inhibited data area 201, and information set by the user. And date, record data that is generated during the operation of the system and needs to be saved at the time of system shutdown or accidental power off,
The data is stored in the rewrite permission data area 202.

As described above, the nonvolatile memory management device according to the first embodiment of the present invention divides the nonvolatile memory into a data area for rewriting and a data area for non-rewriting. Management to reduce the number of data areas that require large-scale data error countermeasures,
The amount of non-volatile memory used can be reduced and data management can be facilitated without taking measures against data errors up to data for which error measures are unnecessary.

(Second Embodiment) Next, with reference to FIG. 3, a memory map of a rewrite-permitted area of the nonvolatile memory 104 according to a second embodiment of the present invention will be described.
3 includes a user data array area 301 and a user data array reference information area 302 that refers to the user data array. User data array area 301
Has a plurality of user data arrays 303 as its array elements.

[0] to [n] have the same structure. Further, the user data array reference information area 302 has pointers for storing a plurality of user data array reference information 304 as array elements thereof.

[0] to [2] have the same structure.

Next, with reference to FIG. 3, an operation of the rewrite permitted area of the nonvolatile memory 104 according to the second embodiment of the present invention will be described. The user data array 303 used by the user at the time of complete initialization or factory shipment is
Using designation information such as the address or the number of each user data array 303, it is initialized to a value that uniquely points without duplication. For example, when the user data array is designated by a number and the numbers are managed in ascending order, each user data array reference information 304

[0] =
0, user data array reference information [1] = 1, and user data array reference information [2] = 2.

Further, by changing the value of the user data array reference information and changing the number of the user data array 303 to be used, the arrangement address in the user data array area 301 is changed, and the address at which writing becomes impossible Can be changed to a new location address. In the case of changing or updating, the number is changed to a number one greater than the highest number assigned to all the user data array reference information 304, thereby completing the change of the value of the user data array reference information 304. .

A user data array having a value smaller than the highest value of the user data array reference information 304 and corresponding to a number not used in any user data array reference information is managed as an unusable user data array due to a write error. Is done.

As described above, the rewrite permitted area of the nonvolatile memory according to the second embodiment of the present invention
By arraying areas for storing user data to be rewritten and providing a large number of user data arrays, and specifying the user data array in use by a number or an address,
Even if the user data array in use becomes unwritable, by changing to a new user data array avoiding the user data array, a write error can be recovered and the management of the unwritable area can be facilitated. .

(Third Embodiment) Next, a memory map of a user data array (303 in FIG. 3) of the nonvolatile memory 104 according to a third embodiment of the present invention will be described with reference to FIG. I do. A user data array 401 (30 in FIG. 3) which is one of the array elements of the user data array area 301
3) the user data area 402 and the management information area 40
The management information area 403 further includes a validity check information storage area 404 for storing checksum data of the user data area 402, and a write error occurrence detection number storage area 405.

Next, the operation of the user data array of the nonvolatile memory 104 according to the third embodiment of the present invention will be described with reference to FIG. In the user data area 402,
Stores data used arbitrarily by the user. At the time of storing the data, checksum data for checking the validity of the write data is calculated, and the checksum data is stored in a validity check information storage area 404 which is a component of the management information area 403.

Also, when an error is detected during data writing,
A memory check is performed on the area in which the error is detected, and when a data write error is also detected in the memory check, the error occurrence count storage area 405 is stored each time.
A write error occurrence count adding means (not shown) for increasing and storing the value of “1” is provided, and when the number of write error occurrences exceeds a predetermined value, writing to another user data area 402 is performed. (Details will be described later).

As described above, the user data array of the nonvolatile memory according to the third embodiment of the present invention is:
The checksum data for confirming the validity of the user data is stored, and the validity of the contents of the user data is confirmed by comparing the checksum data with the checksum data calculated from the user data area at the time of data reading. It is possible to provide a user data validity checking means and a write error occurrence detection number adding means for improving the reliability of the user data area by adding and storing the number of write error detection times and managing the storage.

(Fourth Embodiment) Next, a method for initializing a nonvolatile memory 104 according to a fourth embodiment of the present invention will be described with reference to FIG. The fourth shown in FIG.
The initialization procedure of the non-volatile memory 104 according to the embodiment includes a write-protected area memory check / initialization process 50.
1, write-inhibited data area memory check processing result determination processing 502, and write-inhibited data area write processing 50
3, user data array reference information memory check / initialization processing 504, user data array reference information memory check result determination processing 505, user data array reference information initial value setting processing 506, user data array area initialization Process 507 and user data array management process 508
It is composed of

Next, an initialization operation of the nonvolatile memory according to the fourth embodiment of the present invention will be described with reference to FIG. First, a test pattern is written in all the areas of the non-rewriteable data area 201 of the non-volatile memory 104 by the memory check / initialization processing 501 of the non-rewriteable data area 201, and then the read operation is performed to write the read data and the read data. Collate. Next, all the recorded contents of the rewrite prohibition data area 201 are cleared, and the result of the data collation is notified. In the result determination process 502 of the memory check process of the rewrite prohibition data area 201, the previous data collation result is determined, and when a data error is detected, a system error is notified and the operation of the system is stopped. If the data collation result is a normal end, write processing 503 of the write-protected data area 201 is executed, and data that is not rewritten after product shipment, such as an ID number unique to the system, is written to the rewrite-protected data area.

Next, the user data array reference information area 30
2 performs a memory check / initialization process 504, writes a test pattern in an area for storing user data array reference information 304 that refers to the user data array 303, and then performs a read operation to compare the write data with the read data. I do. Next, the user data array reference information 304 is cleared, and the result of the data collation is notified.

Next, the user data array reference information area 30
In the determination process 505 of the result of the memory check process of No. 2,
The data collation result is determined, and if a data error is detected, a system error is notified and the operation of the system is stopped. If the data collation result is a normal end, an initial value setting process 506 of the user data array reference information 304 for writing a non-overlapping initial value to the user data array reference information 304 is executed.

Next, a user data array area initialization process 507 for initializing the user data array area 301 is executed, and an initial value is written in the user data array area 301. Subsequently, a user data array initial value setting process 508 is executed,
An initial value is set in each user data array 303.

As described above, in the method for initializing a nonvolatile memory according to the fourth embodiment of the present invention, the nonvolatile memory can be initialized and an initial value can be written.
Also, an initial value is set in the user data array reference information, and a user data array for performing data reading is specified,
The initial values needed to specify a new user data array to recover from a write error can be provided.

(Fifth Embodiment) Next, with reference to FIG. 6, a description will be given of a recovery process when an error is detected in the nonvolatile memory 104 according to a fifth embodiment of the present invention. The user data array management processing procedure according to the fifth embodiment includes an error checking flag resetting processing 601, an error occurrence detection number determination processing 602, a user data array head address calculation processing 603, a test data writing processing 604, Non-volatile memory state determination processing 605, user data array data verification processing 606, verification result determination processing 607, error check flag determination processing 608, and write error occurrence detection number addition processing 6
09, error check flag set 610 processing,
It comprises a user data array area capacity check process 611 and a user data array reference information update process 612.

Next, with reference to FIG. 6, the operation of a recovery process when an error is detected in the nonvolatile memory 104 according to the fifth embodiment of the present invention will be described. First, an error checking flag reset process 601 is executed to reset the error checking flag. Subsequently, an error occurrence detection number determination process 602 is executed to determine whether the number of write error occurrence detections of the currently specified user data array 303 does not exceed a specified value. If it does not exceed the specified value, the user data array head address calculation processing 603
To calculate the start address of the designated user data array 303.

Next, test data write processing 604 is executed to write test data to the specified user data array 303, and then, the non-volatile memory state determination processing 605
To determine the result of writing data in the control register (not shown) of the nonvolatile memory 104. If writing is successful, user data array data verification (verification)
Step 606 is executed to verify whether the write data matches the read data. Next, verify result determination processing 6
07 is executed, and if the coincidence between the write data and the read data can be confirmed, the user data array management processing ends. However, if the match between the write data and the read data cannot be confirmed, an error check flag determination process 608 is executed. Also, as a result of the execution of the above-described nonvolatile memory state determination processing 605, the nonvolatile memory 1
Also, when it is determined that the data write to the data 04 has failed, the error checking flag determination processing 608 is executed in the same manner.

The value of the error check flag is determined by the error check flag determination process 608. If this flag is set, it means that write error detection has occurred two or more times in succession. The detection count addition processing 609 is executed to add one to the number of write error occurrence detections of the specified user data array 303.
In other cases, only one write error detection is performed, and the number of write error occurrences is not added. in this case,
There may be an error caused not by an abnormality of the nonvolatile memory 104 but by a power supply interruption during writing.

Next, an error checking flag setting process 610 is executed to store that a write error has been detected once. Returning again to the beginning of the processing procedure, the error occurrence detection number determination processing 602 is executed, and the processing is repeatedly executed until the error disappears. However, if the number of write error occurrences detected in the currently specified user data array 303 exceeds the specified value, it is determined that the reliability of the currently used user data array 303 is low, and a new user data array 303 is stored. Assign.

To allocate a new user data array 303, first, a user data array area capacity check processing 61
1 to check whether there is an unused user data array 303. If there is an unused user data array 303, the user data array reference information update processing 612 is executed, and among the set values of the currently used user data array reference information, a value one larger than the largest set value is set as a new value. It is assigned to the corresponding new user data array 303 as a setting value. When the initial setting value of the user data array reference information is in the ascending order, the user data array 303 next to the currently highest address or number is allocated, and in the descending order, the user data array 303 next to the currently lowest address or number is allocated. Update to assign If there is no unused user data array 303, a new user data array cannot be allocated, so a system error is notified and the operation of the system is stopped.

As described above, the recovery processing method when detecting an error in the nonvolatile memory according to the fifth embodiment of the present invention is a method for recovering data from a nonvolatile memory when a data write error to a specified user data array is detected. The function of the memory is checked, and if there is no abnormality in the operation of the array, the array is used again. If an abnormality is detected, a memory management function capable of allocating a new array can be executed.

(Sixth Embodiment) Next, with reference to FIG. 7, a description will be given of a process of writing user data in the nonvolatile memory 104 according to a sixth embodiment of the present invention. The user data writing processing procedure in the sixth embodiment includes an initial value setting processing 701 of a user data array reference information index i, and a user data area writing processing 702.
A state determination process 703 of the nonvolatile memory 104, a user data area read process 704, a validity check information calculation write process 705, a validity determination process 706, a user data array management process 707, and a user data array reference. It is composed of a judgment processing 708 of the information index i and an addition processing 709 of the user data array reference information index i.

Next, with reference to FIG. 7, the operation of the process of writing user data in the nonvolatile memory 104 according to the sixth embodiment of the present invention will be described. First, in an initial value setting process 701 of the user data array reference information index i, an initial value 0 is set to the user data array reference information index i. In the next user data area writing process 702, the user data is written to the user data area 402 constituting the user data array 303 indicated by the user data array reference information 304 specified by the user data array reference information index i. Here, i is the number of user data arrays 303 to be written.

Subsequent nonvolatile memory state determination processing 7
At 03, the data write result of the control register (not shown) of the non-volatile memory 104 is determined, and if the write is successful, the user data area 402 for reading the user data area 402 indicated by the user data array reference information index i is read. Read processing 704 and validity check information calculation write processing 7
Step 05 is performed to check whether the write data and the read data match. Next, in the validity determination processing 706, when it is determined that the contents of the write data and the read data match, in the user data array reference information index i determination processing 708, the user data array reference information 304 indicates the number of the index i. It is determined whether writing to the user data array 303 has been completed, and if completed, this processing ends. When the user data array 303 to be written still remains, 1 is added to the index i in the user data array reference information index i addition processing 709, and the processing is executed again from the user data area writing processing 702.

When the validity determination processing 706 detects that the contents of the write data and the contents of the read data do not match,
As described in the fifth embodiment of the present invention, the user data array 303 is replaced with the new user data array 303.
The user data array management process 707 is performed, for example, the error is recovered, and after the error recovery, the process is executed again from the user data area writing process 702.

As described above, the user data write processing method of the nonvolatile memory according to the sixth embodiment of the present invention writes arbitrary data to the user data area,
It is possible to confirm that the data has been written, and if a write error is detected, perform error recovery to provide a reliable data write operation.

(Seventh Embodiment) Next, with reference to FIG. 8, a process of reading user data from the nonvolatile memory 104 according to a seventh embodiment of the present invention will be described. The user data read processing procedure in the seventh embodiment includes an initial value setting processing 801 of the user data array reference information index i and a user data array read processing 802.
Validity determination processing 803, user data array reference information index i addition processing 804, user data array read count determination processing 805, user data area initial value setting processing 806, read error notification processing 807, user data Recovery end determination processing 808, user data array management processing 809, user data recovery processing 8
10 and a user data array reference information index i subtraction process 811.

Next, with reference to FIG. 8, the operation of the process of reading user data from the nonvolatile memory 104 according to the seventh embodiment of the present invention will be described. First, in an initial value setting process 801 of the user data array reference information index i, an initial value 0 is set to the user data array reference information index i. In the user data array read processing 802, the user data array information constituting the user data array 303 indicated by the user data array reference information 304 specified by the user data array reference information index i is read, and the validity of the user data array information is also determined. Calculate gender confirmation information. Here, i is the number of times of reading.

In the subsequent validity determination processing 803, it is checked whether the validity check information calculated from the read data matches the value of the validity check information in the user data array 303. In the case of (1), 1 is added to the index value in the user data array reference information index i addition processing 804, and in the user data array read number determination processing 805, if the number of the user data array reference information 304 is not exceeded, the user data array Read processing 8
02 is executed again, and data is read from the user data array 303 to be read next. However, if the index i exceeds the number of the user data array reference information 304, it is determined that there is no user data array 303 storing the correct user data array 303, and the user data area initial value setting processing 806 determines The user sets the default data string previously stored in the non-rewriteable area of the nonvolatile memory 104 in the user data array 303 and executes the read error notification processing 807 to read the user data array 303, Notify outside that the default value was set in the provisional action. Subsequently, the user data recovery end determination processing 808 is executed as described later.

When the validity check information calculated from the read data and the value of the validity check information in the user data array match in the validity judgment processing 803, the user data recovery end judgment processing is similarly performed. Execute 808. That is, if the user data array reference information index i is 0, the user data array in which the error is detected is 1
If it is determined that there is no data, the process is terminated without recovering the user data array. However, if the user data array reference information index i is 1, it is determined that there is one or more user data arrays in which an error has been detected, and the user data array management processing 80 similar to that in the fifth embodiment is performed.
After executing the step 9 and performing error recovery, the user data recovery processing 810 writes the user data string normally read or the default data string.

After executing these processes, the user data array reference information index i is subtracted in a user data array reference information index i subtraction process 811, and the process is executed again from the user data recovery end determination process 808, and an error occurs. After the data recovery of all the user data arrays 303 is completed, this processing ends.

As described above, the user data read processing method of the nonvolatile memory according to the seventh embodiment of the present invention determines the validity of user data information, and performs the other processing even if a data error is detected. , And a normal user data string can be read. Also, if an error occurs in writing to the non-volatile memory due to power failure during data writing, etc., read the already written data or read the data before updating, and recover the user data array that detected the error in writing And a reliable data reading operation can be provided.

[0055]

The method and apparatus for managing a nonvolatile memory according to the present invention are configured as described above, and detect an error due to a write failure due to a power failure at the time of updating data, a device failure, a write life, or the like. Even in this case, the stored data can be read, the error can be recovered, and the nonvolatile memory can be continuously used.

[Brief description of the drawings]

FIG. 1 is a block diagram of a management device of a nonvolatile memory according to a first embodiment of the present invention;

FIG. 2 is a view showing a memory map of the nonvolatile memory shown in FIG. 1;

FIG. 3 is a diagram showing a memory map of a rewrite permission area of a nonvolatile memory according to a second embodiment of the present invention;

FIG. 4 is a diagram showing a memory map of a user data array in a nonvolatile memory according to a third embodiment of the present invention;

FIG. 5 is a flowchart showing a method for initializing a nonvolatile memory 104 according to a fourth embodiment of the present invention;

FIG. 6 is a flowchart showing user data array management processing of a nonvolatile memory according to a fifth embodiment of the present invention;

FIG. 7 is a flowchart showing a process of writing user data in a nonvolatile memory according to a sixth embodiment of the present invention;

FIG. 8 is a flowchart showing a process of reading user data from a nonvolatile memory according to a seventh embodiment of the present invention;

FIG. 9 is a flowchart showing a data reading process of a nonvolatile memory according to the related art.

[Explanation of symbols]

 Reference Signs List 101 Microprocessor (CPU) 102 RAM 103 ROM 104 Nonvolatile memory 105 Input interface 106 Information input means 107 Output interface 108 Information output means 109 Data bus 201 Rewrite prohibited data area 202 Rewrite permitted data area 301 User data array area 302 User Data array reference information area 303 User data array (array element)

[0] to [n] 304 User data array reference information

[0] to [2] 401 User data array 402 User data area 403 Management information area 404 Validation information storage area 405 Write error occurrence detection number storage area

Claims (9)

[Claims] An entire data area of a nonvolatile memory for storing user data is divided into a rewrite-permitted data area and a rewrite-inhibited data area, and data for changing contents is stored in the rewrite-permitted data area. A method for managing a non-volatile memory, characterized in that data whose contents are not changed is stored in the rewrite-inhibited data area. 2. The rewrite permission data area is composed of a plurality of user data arrays each having an array element.
The user data array is provided with a user data area and a management information area having a validity check information storage area and a write error occurrence count storage area, and the user data area stores data to be used arbitrarily. The sex check information storage area stores validity check information for checking the validity of the contents of the user data area, and the write error occurrence count storage area stores the write error occurrence count for the same data area. Claim 1.
The management method of the nonvolatile memory described in the above. 3. A plurality of user data array reference information is provided in said rewrite permission data area, and said user data array reference information corresponding to designation information indicating each user data array of said user data array area without overlapping each other. 3. The method for managing a nonvolatile memory according to claim 2, wherein the information is recorded in a non-volatile memory. 4. A validity of the contents of the user data array indicated by the user data array reference information is determined, and if the validity cannot be confirmed, an array of the user data array indicated by another user data array reference information. 4. The method according to claim 3, wherein the validity of the contents of the element is determined, and control is performed so as to output the data of the user data array for which the validity has been confirmed. 5. A method for determining the validity of the user data array indicated by the user data array reference information, and verifying the function of writing or reading the user data array if the validity cannot be confirmed. If it is determined that the write or read function for the user data array is normal, the user data array is continuously used,
If it is determined that the write or read function is defective, the user data array reference information indicating the user data array is updated, and an error recovery is performed so that the user data array indicated by the updated user data array reference information is used. The method according to claim 3, wherein the processing is performed. 6. The user data array reference information is completely initialized or initialized to non-overlapping ascending or descending order user data array designation information at the time of factory shipment, and an error that cannot be rewritten in the user data array is detected. At the time of later recovery, in the case of ascending order, update to the next specified information after the largest specified information among the currently used specified information, and in the case of descending order, the smallest specified among the currently used specified information 6. The method according to claim 3, wherein the specified information is updated to the next specified information. 7. The specified information of the user data array reference information is initialized in accordance with the order of the corresponding user data array, and when the power supply is restored after power-off during write operation, the user indicated by the user data array reference information is indicated. By determining the contents of the data array and the corresponding validity check information, the user data array that was being updated at the moment when the power was turned off during the write operation is specified, and error recovery processing is performed. The method for managing a nonvolatile memory according to claim 3. 8. An error occurrence detection of the user data array every time the function verification of the non-volatile memory is performed without confirming the validity of the currently used user data array indicated by the user data array reference information. When the frequency information is updated and the function verification is performed more than a predetermined number of times for the same user data array, the user data array reference information indicating the currently used user data array is changed, and a new user data array corresponding thereto is changed. 6. The method for managing a nonvolatile memory according to claim 5, wherein: 9. A nonvolatile memory for storing user data, and control means for controlling reading and writing of data to and from said nonvolatile memory, wherein said control means controls said nonvolatile memory for said nonvolatile memory. Wherein when a data error is detected during operation, the data error is avoided and normal operation is continued. Memory management device.