JP2002175219A - Data memory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To write and read data without damaging high correlation as to the data of the high correlation. SOLUTION: A CPU 1 writes the data A, B, C, D, E in respective areas within the first memory area 11 provided in a data storage part 3, and writes the data in order also in the second memory area 12 and the third memory area 13. When the data are read out, the CPU selects anyone of the first-third memory areas 11, 12, 13 applied with no electric shock, and reads out the data from the selected memory area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a data storage device, and more particularly to a data storage device suitable for use in a nonvolatile memory such as a flash memory.

[0002]

2. Description of the Related Art When data is written in a nonvolatile memory, an electrical shock may be generated on the nonvolatile memory, the microcomputer, or a signal line connecting the nonvolatile memory and the microcomputer for some reason. As a result, data that was originally not intended to be written may be written to the nonvolatile memory, or the data writing may be stopped.

[0005] However, various data reading methods have been conventionally proposed so that accurate data can be read from the nonvolatile memory even when such an electric shock occurs.

For example, by writing the same data to three areas on a memory, and taking a majority decision in each area when reading, accurate data can be obtained even when the power is turned off during data writing. A technology that can be read has been proposed.

More specifically, as shown in FIG. 3, a conventional non-volatile memory 50 includes a first memory area 51, a second memory area 52, and a third memory area 53. Further, the first memory area 51 includes A1, B1.
・ ・, E1 area is provided. The second memory area 52 includes areas A2, B2,..., E2. The third memory area 53 includes A3, B3,.
It has three areas.

The data A,
When writing B, C, D, and E, data A
1, A2, A3 and write data B in areas B1, B
2, B3, and write data C in areas C1, C2, C
3, data D is written to areas D1, D2, D3, and data E is written to areas E1, E2, E3.

When reading data A, areas A1,
Take the majority decision of the data written in A2 and A3,
A large number of data are read as data A. When reading the data B, the majority of the data written in the areas B1, B2, and B3 is determined, and the increased data is read as the data B. The same applies to data C, D, and E.

[0008]

When the above-described data writing method is adopted, no particular problem occurs when the data A, B, C, D, and E have no correlation with each other. Occurs.

For example, it is assumed that data A indicates the total number of prints, data B indicates the number of prints of only A4 landscape paper, and data C indicates the number of double-sided prints. At this time, data A,
B and C each have a correlation.

In the data writing method described above, if the power is turned off when the data A is written to the area A3, only the data A is updated. Therefore, the relationship between the data A and the data B and the relationship between the data A and the data C is broken, and even if the data is read by the above-described method, the data indicating the exact number of prints cannot be read.

The present invention has been proposed in order to solve the above-mentioned problems, and has been proposed for highly correlated data.
It is an object of the present invention to provide a data storage device capable of writing and reading data without breaking the correlation.

[0012]

According to the first aspect of the present invention,
A storage unit having a plurality of memory areas for storing data for each predetermined unit, and for each memory area of the storage unit, data having high correlation is written into one memory area while maintaining the correlation. Writing means for repeatedly performing a process of writing to another memory area while maintaining the correlation.

[0013] The storage means is provided with a plurality of memory areas for storing input data for each predetermined unit. When writing highly correlated data to the storage means, the writing means writes the data to a plurality of memory areas provided in the storage means a plurality of times while maintaining the data correlation.

According to a second aspect of the present invention, a memory area which has not been subjected to an electric shock when data is written is selected from each memory area of the storage means, and the data written in the selected memory area is stored. The apparatus further comprises reading means for reading.

In a memory area that has been subjected to an electric shock due to a power-off or the like at the time of writing data, erroneous data has been written due to the electric shock or data has been written only halfway. On the other hand, in a memory area that has not been subjected to an electric shock, data having a high correlation is stored while maintaining the correlation. Therefore, the reading means selects a memory area other than the memory area subjected to the electric shock at the time of data writing, and reads out the data of the selected memory area, thereby obtaining data in a state where the correlation is maintained. .

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, a data storage device according to a first embodiment of the present invention comprises a central processing unit (CPU) 1 for writing and reading data, and a CP.
A read-only memory (ROM) 2 storing a control program of U1 and a data storage unit 3 composed of a nonvolatile memory are provided. These are connected to each other via the data bus 4.

The data storage unit 3 stores the first memory area 1
1, a second memory area 12, and a third memory area 13. Further, the first memory area 11
Has areas A1, B1,..., E1. The second memory area 12 includes A2, B2,.
Each area of E2 is provided. Third memory area 13
Has areas A3, B3,..., E3.

The first to third memory areas 11, 12,
13 stores data A, B, C, D, and E. Here, the data A, B, C, D, and E have high correlation, and are not limited to, for example, a case where all are correlated with each other, and may include independent data in part.

Although the first memory area 11 has five areas, the present invention is not limited to this. That is, a desired number of areas can be provided in the first memory area 11 according to the correlation of the data to be written. Similarly, in the second and third memory areas, a desired number of areas can be provided according to the correlation of data to be written.

Then, data A, B,
When C, D, and E flow, the CPU 1 writes these data into the data storage unit 3 as follows.

The CPU 1 collectively writes the data A, B, C, D, and E into the first memory area 11. That is,
Data A is written to area A1, data B is written to area B1, data C is written to area C1, data D is written to area D1, and data E is written to area E1.

Next, the CPU 1 stores data A, B, C,
D and E are written together in the second memory area 12.
That is, data A is stored in area A2, data B is stored in area B
2, data C in area C2, and data D in area D2.
Then, the data E is written to the area E2.

Finally, the CPU 1 stores the data A, B, C,
D and E are collectively written to the third memory area 13.
That is, data A is stored in area A3, data B is stored in area B
3, data C in area C3, and data D in area D3.
Then, the data E is written to the area E3.

As described above, the CPU 1 outputs the data A,
A process of writing all of B, C, D, and E into the first memory area 11, then writing all of them into the second memory area 12, and finally writing all of them into the third memory area 13 is performed.

On the other hand, when reading data, the CPU
1 is a first memory area 1 according to a writing situation.
1, second memory area 12, third memory area 13
Is selected.

If there is no electric shock such as power-off at the time of writing data, the CPU 1 may select any of the first to third memory areas 11, 12, and 13. It is preferable to select the stored third memory area 13.

If there is an electric shock when data is written to the first memory area 11, the CPU 1
The memory area 12 or the third memory area 13 can be selected, but it is preferable to select the third memory area 13 in which the latest data is stored.

If there is an electric shock at the time of writing data to the second memory area 12, the CPU 1
Memory area 11 or the third memory area 13 can be selected. Note that the third memory area 13 stores data before update, and the first memory area 11 stores the latest data after update.
Preferably, 1 selects the first memory area 11.

If there is an electric shock when data is written to the third memory area 13, the CPU 1
Can be selected, but it is preferable to select the second memory area 12 in which the latest data is stored.

Then, the CPU 1 reads the data A, B, C, D, and E from the selected area and supplies the data to a predetermined circuit via the data bus 4.

As described above, the data storage device according to the first embodiment collectively writes highly correlated data to each memory area, and collectively reads data from a memory area where there is no electrical shock. Thus, it is possible to prevent a situation in which only a part of the data is updated and the relationship between the data is not broken. In other words, even if there is an electric shock such as turning off the power at the time of writing data, highly correlated data before or after updating can be read, so that the correlation state of the data must always be maintained. Can be. Further, since the data storage device divides the memory area of the data storage unit 3 into three large areas, it can be controlled relatively easily.

Next, a second embodiment of the present invention will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted. The data storage device according to the second embodiment is suitable for use when data A, B, C and data D, E have high correlation.

As shown in FIG. 2, the data storage device according to the present embodiment has a C
PU1 and ROM storing a control program for CPU1
2 and a data storage unit 3 composed of a nonvolatile memory. These are connected to each other via the data bus 4.

The data storage section 3 includes first to third memory areas 21, 22, 23 for storing data A, B, and C.
And fourth to sixth memory areas 24, 25 and 26 for storing data D and E.

The first memory area 21 includes A1, B1,
Each area of C1 is provided. Second memory area 22
Has areas A2, B2, and C2. The third memory area 23 includes areas A3, B3, and C3.

The fourth memory area 24 has areas D1 and E1. The fifth memory area 25 stores D
2 and E2. The sixth memory area 26 has areas D3 and E3.

Then, data A, B,
When C, D, and E flow, the CPU 1 writes these data into the data storage unit 3 as follows.

The CPU 1 collectively writes the data A, B, and C into the first memory area 21. That is, data A
In the area A1, the data B in the area B1, and the data C in the area C1. Next, the CPU 1 outputs data A,
B and C are written together in the second memory area 22.
Finally, the CPU 1 collects the data A, B, and C into a third
Is written to the memory area 23.

Further, the CPU 1 writes the data D and E together in the fourth memory area 24. That is, data D is written in area D1, and data E is written in area E1. Next, the CPU 1 collectively writes the data D and E into the fifth memory area 25. Finally, the CPU 1 collectively writes the data D and E into the sixth memory area 26.

As described above, the CPU 1 sets the data A,
B and C are written in the first memory area 21, and then the second
Then, a process of writing to the third memory area 23 is performed. Then, data D and E
Is written to the fourth memory area 24, then to the fifth memory area 25, and finally to the sixth memory area 2
6 is performed.

On the other hand, when reading data, the CPU
1 selects one of the first to third memory areas 21, 22, 23 according to the writing situation, and further selects one of the fourth to sixth memory areas 24, 25, 26. Select one.

If there is no electric shock such as power-off at the time of writing data, the CPU 1 may select any one of the first to third memory areas 21, 22, 23. Fourth to sixth memory areas 24, 2
Any of 5 and 26 may be selected. However, it is preferable to select the third memory area 23 and the sixth memory area 26 in which the latest data is stored.

The first to third memory areas 21, 22, 22
If there is an electric shock while writing data to any one of the memory areas 23, the CPU 11 executes the first to third steps in the same manner as the selection of the memory area in the first embodiment.
Of the memory areas 21, 22, and 23 except for the memory area subjected to the electric shock, and selects one of them. At this time, the fourth to sixth memory areas 24, 2
Any one of the fifth and 26 may be selected, but it is preferable to select the sixth memory area 26 in which the latest data is stored.

The fourth to sixth memory areas 24,
If there is an electric shock while writing data to any of the memory areas 25 and 26, the CPU 11 proceeds to the fourth to sixth memory areas 24 in the same manner as the selection of the memory area in the first embodiment. , 25, and 26 except for the memory area subjected to the electric shock, and selects one of them. At this time, the first to third memory areas 21,
Any one of 22, 22 can be selected, but it is preferable to select the third memory area 23 in which the latest data is stored.

Then, the CPU 1 selects data A, B, C and data D, E from the selected memory area, respectively.
And supplies it to a predetermined circuit via the data bus 4.

As described above, the data storage device according to the second embodiment collectively writes highly correlated data in each memory area, and stores data from a memory area which has not been subjected to an electric shock such as power-off. By reading them all together, it is possible to prevent a situation in which only a part of the data is updated and the relationship between the data is broken.

The data storage device has a data storage unit 3
By dividing the memory area into smaller areas according to the correlation of data, it is possible to read as much updated data as possible even if the power is turned off.

In this embodiment, data A, B,
Although the case where C and data D and E are correlated has been described, the present invention can be applied even when only one of data A, B and C and data D and E are correlated. it can.

[0050]

According to the first aspect of the present invention, after writing highly correlated data to one memory area in each memory area of the storage means while maintaining the correlation, the correlation is further increased. By performing a process of writing to another memory area a predetermined number of times while maintaining the state, the data can be stored while maintaining the correlation state.

According to a second aspect of the present invention, a memory area which has not been subjected to an electric shock when data is written is selected from each memory area of the storage means, and the data written in the selected memory area is read. As a result, the data maintaining the state of the correlation can be read as it is.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a data storage device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a data storage device according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a schematic operation of a conventional data storage device.

[Explanation of symbols]

 1 CPU 2 ROM 3 Data storage unit

Claims (2)

[Claims] 1. A storage unit having a plurality of memory areas for storing data in predetermined units, and a memory having high correlation with one memory in each memory area of the storage unit while maintaining the correlation. And a writing unit for performing a predetermined number of times of writing to another memory area while maintaining the correlation after writing to the area. 2. A reading means for selecting a memory area which has not been subjected to an electric shock at the time of writing data from each memory area of said storage means, and reading data written in the selected memory area. The data storage device according to claim 1.