JP2000194605A - Refreshing device of flash memory, its refreshing method, and flash memory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the abnormality a flash memory and to repair it without having any effect on system operation by providing a device processing means which detects the abnormality of an active and a standby system flash memory. SOLUTION: When initially activated, a 1st flash memory initial abnormality detecting means 11 of a device processing part 1 checks program information on a ROM program storage part 21, the in-operation lash memory 22, and the standby flash memory 23 of a device storage part (memory) 2. A flash memory active/standby switching means 12 activates the detected normal flash memory 22. A 2nd flash memory periodic abnormality detecting means 13 is periodically activated by a periodic timer in the system operation to check program information on the standby flash memory 23. When the standby flash memory 23 is abnormal, the normal active flash memory 22 is used for writing and the program information on the standby flash memory 23 is repaired.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a flash memory refresh apparatus, a flash memory refresh method, and a flash memory that detect an abnormality in a flash memory during system operation and perform autonomous repair.

[0002]

2. Description of the Related Art A flash memory is a nonvolatile memory in which data can be written and erased by an electric operation.

As a method of refreshing such a flash memory, for example, Japanese Patent Application Laid-Open No. 8-19079
No. 6 is disclosed.

In this method, first, read data from the same address is compared for each address in both the program verify mode and the erase verify mode. Next, the data of the memory cell corresponding to the mismatched data is rewritten. Further, a defective block is searched by comparing the added value of read data in both the program verify mode and the erase verify mode for each block.

The above-described comparison is performed for each address in the defective block, and the data in the memory cell corresponding to the mismatched data is rewritten. This makes it possible to specify the memory cell holding the defective data and repair the defective data separately from the verify operation immediately after writing or erasing data.

As another refreshing method, for example, there is a method disclosed in Japanese Patent Application Laid-Open No. 9-204367.

This is a flash disk card equipped with a flash memory and an ECC (error detection and correction) circuit. For flash disk cards,
When performing initialization processing after power-on, the MPU in the flash disk card reads out all data written in the flash memory as part of the initialization processing.

Next, when an error is detected and corrected for the read data by the ECC circuit, the corrected data is written to the flash memory. Thereby, without lowering the data reading speed,
Data retention characteristics are enhanced.

[0009]

However, since none of the above-mentioned prior arts takes into account abnormality detection and repair during system operation, an abnormality in the flash memory is detected and refreshed during system operation. There is a problem that you can not.

The present invention has been made in view of such a situation, and it is possible to detect and repair an abnormality in a flash memory without affecting system operation even during system operation. An object of the present invention is to provide a flash memory refresh device, a refresh method thereof, and a flash memory.

[0011]

According to the present invention, there is provided a flash memory refresh apparatus for detecting an abnormality in an active flash memory, a standby flash memory, and an active flash memory and a standby flash memory. It is characterized by comprising processing means. Further, the apparatus processing means includes: first flash memory initial abnormality detection means for checking the active and standby flash memories at the time of initial system startup; and Flash memory operation / standby switching means for switching any one to the startup system, second flash memory periodic abnormality detection means periodically started during system operation and checking the flash memory of the standby system, and abnormality is detected as a result of the check In this case, a flash memory refresh unit for rewriting the program information of the standby flash memory with normal program information can be provided. Further, the check by the first flash memory initial abnormality detection means may include an abnormality check of the active and standby flash memories. Further, the check by the second flash memory regular abnormality detection means may include an abnormality check of the standby flash memory. Also, the second flash memory periodic abnormality detecting means 1
3 can calculate a checksum of several bytes of program information at a fixed period, and perform a check by comparing with a checksum already written at the time of writing to the memory. A flash memory refresh method according to claim 6, wherein the flash memory refresh method detects and repairs an abnormality in the active flash memory and the standby flash memory. The method includes a first step of detecting an abnormality. In the first step,
A second step of checking the active and standby flash memories at the time of initial system startup, and a third step of switching one of the active and standby flash memories to the active system based on the check result. A fourth step of periodically starting up during system operation and checking the flash memory of the standby system, and rewriting the program information of the flash memory of the standby system with normal program information when an abnormality is detected as a result of the check. And a fifth step. Further, the second step may include a step of performing an abnormality check on the flash memories of the active system and the standby system. Further, the fourth step may include a sixth step of performing an abnormality check of the standby flash memory. Further, the fourth or sixth step includes a step of calculating a checksum of program information for several bytes at a fixed period and performing a check by comparing with a checksum already written at the time of writing to the memory. You can do so. The flash memory according to the eleventh aspect is characterized in that it has a dual configuration of an active flash memory and a standby flash memory. In the flash memory refresh apparatus, the refresh method, and the flash memory according to the present invention, the flash memory has a dual configuration of an active system and a standby system, and an abnormality check of the standby flash memory is performed even during system operation. At the same time, when checking for abnormalities, program information for several bytes is checked at a fixed cycle.

[0012]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing a flash memory according to the present invention. The flash memory shown in FIG. 1 has a dual configuration of an active flash memory 22 and a standby flash memory 23.

The flash memories 22 and 23 are connected to a bus 25. The bus 25 includes a CPU 20,
The ROM 21 and the RAM 24 are connected.

FIG. 2 is a block diagram showing an embodiment of a flash memory refresh apparatus according to the present invention, and FIG.
3 is a flowchart for explaining the operation of the refresh device of the flash memory of FIG. 2; Note that, in the drawings described below, parts common to FIG. 1 are denoted by the same reference numerals.

A flash memory refresh device (hereinafter simply referred to as a refresh device) shown in FIG. 2 is a device processing unit (computer: computer) that operates under program control.
Central processing unit (CPU) 1 and device storage unit (memory) 2
And

The device processing unit 1 includes a first flash memory initial abnormality detecting unit 11, a flash memory operation / standby switching unit 12, a second flash memory periodic abnormality detecting unit 13, and a flash memory refreshing unit 14.

The first flash memory initial abnormality detecting means 11 detects the RO of the device storage unit (memory) 2 at the time of initial startup.
M program storage unit 21, active flash memory 2
2 and the program information of the flash memory 23 of the standby system is checked. In addition, the first flash memory initial abnormality detecting means 11 also performs hardware initialization, determination of an active system for starting a program, and the like at the time of initial startup.

If the above is detected as a result of the check,
The CPU 1 is notified of the abnormality and waits for forced download of the program.

Flash memory operation / standby switching means 12
Starts the normal flash memory 22 or 23 detected by the first flash memory initial abnormality detecting means 11.

The second flash memory periodic abnormality detecting means 13 is periodically started by a periodic timer during the operation of the system, and checks the program information of the standby flash memory 23 of the device storage unit (memory) 2.

As a result of the check, if the standby flash memory 23 is abnormal, the normal operating flash memory 22 is used for writing and the standby flash memory 2 is used.
3 is restored (refreshed).

The device storage unit (memory) 2 shown in FIG.
An OM program storage unit 21, an active flash memory 2, and a standby flash memory 23 are provided.

The ROM program storage section 21 stores program information necessary for the operation of the first flash memory initial abnormality detecting means 11 and the operation of the flash memory operation / standby switching means 12.

The active flash memory 22 and the standby flash memory 23 store application program information by program download or the like.

Next, the operation of the refresh device having such a configuration will be described with reference to FIG. First, at the time of initial startup, the first flash memory initial abnormality detecting means 11
As a result, the program information in the active flash memory 22 is checked (step A1). In this case, the checksum of all data (all byte data is added to calculate a two's complement) and the checksum already written at the time of writing to the memory are compared at once.

Next, in order to check the program information of the standby flash memory 23, the checksums of all data are calculated (all byte data are added and two's complement is calculated), and the data is already written in the memory. Compare the written checksum at once (step A
2).

Next, the result of the check is determined, and if the checksums match, it is determined to be normal.
If the checksums do not match, it is determined to be abnormal (step A3).

As a result of the judgment, any flash memory 2
If both are normal, the program is started using the flash memory 22 (step A4). If it is determined that only one of them is normal, the program is started using one of the normal flash memories 22 or 23.

The flash memories 22, 23
Is switched by the flash memory operation / standby switching unit 12 in FIG.

As a result of the judgment, if none of them is normal,
The CPU 1 of FIG. 2 is notified of an abnormality and waits for forced download of the program (step A5).

Next, the operation during operation of the system will be described with reference to FIG. First, during system operation, the second
The program information of the standby flash memory 23 is checked by the flash memory periodic abnormality detecting means 13 (step A2). In this case, the checksum of several bytes of program information is calculated at a fixed period and compared with the checksum already written at the time of writing to the memory.

As a result of comparison, if they match, it is determined to be normal, and if they do not match, it is determined to be abnormal (step A3).

If it is determined that the operation is normal, the flash memory abnormality check regular timer is started (step B2). If it is determined to be abnormal, the program information in the normal operating flash memory 22 is copied (written) over the standby flash memory 23 and repaired (refreshed) (step B1).

As described above, in the present embodiment, since the flash memories 22 and 23 have a dual configuration (operation / standby), it is necessary to check the abnormality of the standby flash memory 23 even during system operation. Can be. In addition, at the time of the abnormality check, the program information of several bytes is checked at a constant cycle, so that it is possible to prevent a burden on the functions and processing of the system.

[0035]

As described above, according to the flash memory refresh apparatus, the refresh method, and the flash memory according to the present invention, the flash memory has a dual configuration of an active system and a standby system, and the flash memory is in standby even during system operation. The system flash memory is checked for abnormalities, and at the time of checking for abnormalities, several bytes of program information are checked at regular intervals, thus affecting system operation even during system operation. Without detecting an abnormality in the flash memory, the flash memory can be repaired.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a flash memory of the present invention.

FIG. 2 is a block diagram showing one embodiment of a refresh device for a flash memory according to the present invention;

FIG. 3 is a flowchart for explaining the operation of the flash memory refresh device of FIG. 2;

FIG. 4 is a flowchart illustrating an operation of the flash memory refresh device of FIG. 2 during system operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Device processing unit 2 Device storage unit 11 First flash memory initial abnormality detection unit 12 Flash memory operation / standby switching unit 13 Second flash memory periodic abnormality detection unit 14 Flash memory refresh unit 21 ROM program storage unit 22 Operating system Flash memory 23 Standby flash memory 25 Bus

Claims (11)

[Claims] 1. An apparatus for refreshing a flash memory, comprising: an active flash memory; a standby flash memory; and device processing means for detecting an abnormality in the active and standby flash memories. 2. The apparatus processing means comprises: first flash memory initial abnormality detecting means for checking the active and standby flash memories at the time of initial system startup; and Flash memory operation / standby switching means for switching any of the flash memory of the standby system to the activation system; second flash memory periodic abnormality detection means that is periodically activated during system operation and checks the flash memory of the standby system; 2. The flash memory according to claim 1, further comprising: a flash memory refresh unit that rewrites program information of the standby flash memory to normal program information when an abnormality is detected as a result of the check. Refresh device for flash memory. 3. The refresh of the flash memory according to claim 2, wherein the check by the first flash memory initial abnormality detection unit includes an abnormality check of the flash memories of the active system and the standby system. apparatus. 4. The flash memory refresh device according to claim 2, wherein the check by the second flash memory periodic abnormality detection means includes an abnormality check of the standby flash memory. 5. The second flash memory periodic abnormality detecting means 13 calculates a checksum of several bytes of program information at a fixed period and compares the checksum with a checksum already written at the time of writing to the memory. 5. The flash memory refresh device according to claim 2, wherein a check is performed. 6. A flash memory refresh method for detecting and repairing an abnormality in an active flash memory and a standby flash memory, wherein the first method detects an abnormality in the active and standby flash memories. A method for refreshing a flash memory, comprising the steps of: 7. The first step includes checking a flash memory of the active system and the standby system at the time of initial startup of the system, and the operating system and the standby system based on a result of the check. A third step of switching any one of the flash memories to the activation system, a fourth step of periodically starting the flash memory during system operation and checking the flash memory of the standby system, and as a result of the check, an abnormality is detected. 7. The flash memory refresh method according to claim 6, further comprising: a fifth step of rewriting the program information of the standby flash memory into normal program information. 8. The flash memory refresh method according to claim 7, wherein the second step includes a step of performing an abnormality check on the active and standby flash memories. 9. The flash memory refresh method according to claim 7, wherein the fourth step includes a sixth step of performing an abnormality check on the standby flash memory. 10. The fourth or sixth step includes calculating a checksum of several bytes of program information at a fixed period, and comparing the checksum with a checksum already written at the time of writing to the memory. The method for refreshing a flash memory according to claim 7, further comprising a step of performing. 11. A flash memory having a dual configuration of an active flash memory and a standby flash memory.