JP4661086B2 - Nonvolatile memory device and nonvolatile memory erasing and writing method - Google Patents

Description

  The present invention relates to a nonvolatile memory device using a nonvolatile memory such as a flash memory, and a method for erasing and writing to the nonvolatile memory.

  In recent years, a memory card equipped with a non-volatile memory has expanded its market as a recording medium for digital cameras and mobile phones. With the increase in memory card capacity, the use is expanding from recording a small capacity of data files, still images, etc. to moving picture recording that requires a larger capacity.

  However, NAND-type flash memory, which is mainly used as a non-volatile memory for memory cards, has a physical block capacity of 16 kB as a data erasing unit as its capacity increases (mainly flash memory of 128 MB or less). Memory) to 128 kB (mainly flash memory of 128 MB or more). Nevertheless, in the file system for writing data to the memory card, the cluster serving as a data writing unit remains 16 kB and has not changed.

  Therefore, in the former small capacity memory card (mainly capacity up to 128MB), the capacity of the cluster when data is written to the memory card and the erase unit of the NAND type flash memory mounted in the memory card The physical blocks to be equal. However, as the capacity increases, more specifically, from a nonvolatile memory having a capacity value exceeding 128 MB, a cluster capacity of 16 kB, which is a unit for writing data to the memory card, and a NAND mounted in the memory card Degradation of write performance when the size of the physical block, which is the erase unit of the flash memory of the type, is different from 128 kB, and the file written to the memory card has fragmented. Was invited.

  FIG. 1 to FIG. 4, FIG. 9 to FIG. 13, and FIG. 17 to FIG. 23 show how data is written to a non-volatile memory inside the memory card in a state where fragmentation occurs in a conventional memory card. It explains using.

  FIG. 1 is a block diagram showing a nonvolatile memory device and a host that controls the nonvolatile memory device. In FIG. 1, 101 is a memory card which is a non-volatile storage device, 102 is a host for controlling the memory card 101 to write and read data to and from the memory card 101, and 103 is a non-volatile memory inside the memory card. Is a flash memory. Here, the flash memory 103 will be described using a 128 MB flash memory. A controller 104 is provided inside the memory card 101 and stores data in the flash memory 103 in response to write and read commands from the host 102 or reads data from the flash memory 103. Reference numeral 105 denotes an erased table indicating information on whether each physical block in the flash memory 103 has been erased or written. Reference numeral 106 denotes a logical / physical conversion table for converting an address designated by the host 102 (hereinafter referred to as a logical address) and an address of the flash memory 103 (hereinafter referred to as a physical address).

  FIG. 2 is an internal block diagram of the flash memory 103. The flash memory 103 includes a plurality of physical blocks 201 (PB0 to PB1023). The physical block 201 is an erasing unit that can erase data collectively, and has a capacity of 128 kB.

  FIG. 3 is a block diagram inside the physical block 201. The physical block 201 is composed of a plurality of physical pages 301 (PP0 to PP63). The physical page 301 is a writing unit for writing data, and each has a capacity of 2 kB. The cluster, which is a unit in which the host 102 logically writes data, is 16 kB, but this value does not match the capacity 128 kB of the physical block 201 and the capacity 2 kB of the physical page 301. Therefore, a partial physical block 302 having a capacity of 16 kB is configured in units of 8 consecutive physical pages. The partial physical block 302 is a unit of data logically handled by the controller 103 assuming data writing from the host. The physical block 201 is logically divided into eight partial physical blocks 302 and the host 102 Write data from.

  FIG. 4 is a diagram showing logical data management inside the memory card 101. The memory capacity of the flash memory 103 mounted on the memory card 101 is 128 MB. Generally, however, the flash memory 103 may have an initial defective block or a defective block due to repeated rewriting. Is the capacity of the memory card 101. Here, 125 MB is a capacity visible to the host 102.

  The logical block 402 is allocated from 0 to 7999 in order of 16 kB for writing 125 MB from the host 102. This logical block forms a logical group in units of 128 kB, which is equal to the physical block that is the erase unit of the cluster flash memory 103.

  Next, erasing of logical block data from the host 102 will be described.

  FIGS. 17 and 18 are a diagram and a flowchart showing the internal operation of the memory card 101 when the host 102 logically erases data in one logical block 402 of the memory card 101. FIG. “Logically erasing” means that when the host 102 reads data from the memory card 101, all 0xFF data can be read. The flash memory 103 of the memory card 101, specifically, the host 102 This represents a case where data in logical block 2 of logical group 0 is erased.

  First, at the writing start time of the flowchart, the data of the logical blocks 0 to 7 belonging to the logical group 0 has been written in the physical block A of the flash memory 103 in the memory card 101, and the physical data that has been erased as a block for rewriting. There is a block B, which corresponds to the state of FIG.

  Next, in state 1201, logical block 0 is read from read source physical block A and written to write destination physical block B. In state 1202, logical block 1 is read from read source physical block A and written to write destination physical block B.

  In the state 1203, the logical block 2 to be erased by the host 102 is written to the write destination physical block B with all data 0xFF.

  Thereafter, the processes of reading logical blocks 3 to 7 from the read source physical block A to the states 1204 to 1208 and writing to the write destination physical block B are sequentially performed. FIG. 17B shows a state when the state 1208 is finished.

  Finally, in the state 1209, the read source physical block A is physically erased, and the process is terminated. The state at this time is shown in FIG.

  As described above, in the conventional erasure processing from the host 102, it is necessary to perform writing on all physical pages of the write destination physical block.

  The time required for this data erasing process is that the time required for reading one page is 265 μs (the busy time 25 μs until reading is possible + the data transfer time 240 μs for reading), and the time required for writing one page is 360 μs (writing Data transfer time 160 μs + time required for writing 200 μs) From the condition of 1 ms for erasing one block, it becomes 265 μs × 8 × 7 + 360 μs × 8 × 8 + 2 ms = 39880 μs, and it takes 39880 μs.

  Next, data writing from the host 102 to the previously erased logical block will be described.

  FIGS. 19 and 20 are a diagram and a flowchart showing the internal operation of the memory card 101 when the host 102 writes data to the logical block 402 that was previously erased from the memory card 101.

  First, at the writing start time of the flowchart, the data of logical blocks 0 to 7 belonging to the logical group 0 has been written to the physical block B of the flash memory 103 in the memory card 101, and the data of the logical block 2 is logically erased. All are filled with 0xFF data. There is an erased physical block C as a block for rewriting, which corresponds to the state of FIG.

  Next, in state 1401, logical block 0 is read from read source physical block B and written to write destination physical block C.

  Thereafter, the processes of reading logical blocks 1 to 7 from the read source physical block B to the states 1402 to 1408 and writing to the write destination physical block C are sequentially performed. FIG. 19B shows a state when the state 1408 is finished.

  Finally, in the state 1309, the read source physical block B is physically erased, and the process is terminated. The state at this time is shown in FIG.

  As described above, in the writing process to the logically erased logical block from the conventional host 102, since the data is already written at 0xFF, a new physical block (physical block C in this case) is required. It is necessary to write to all physical pages of the physical block.

  The time required for this writing process is the same as the erasing time, which is 265 μs × 8 × 7 + 360 μs × 8 × 8 + 2 ms = 39880 μs, and it takes 39880 μs. That is, since it takes 39880 μs to write 16 kB, the writing speed is about 0.4 MB / sec.

  Based on the above erasure / write processing, a description will be given of processing in the case where a plurality of files are written from the host 102 as an actual use example, after which some files are erased and new files are written.

  9 to 13 are diagrams showing a process of writing and erasing from the host 102 to the memory card 101. FIG. First, in FIG. 9, the file 1 is written in the last logical block of the logical group 9, but the logical groups 10 to 12 are in an erased state.

  FIG. 10 shows a state in which the file 1 having a capacity of 48 kB is first written to the logical blocks 80 to 82 of the logical group 10 from this state.

  Thereafter, file 2 having a capacity of 16 kB, file 3 having a capacity of 64 kB, file 4 having a capacity of 96 kB, file 5 having a capacity of 16 kB, file 6 having a capacity of 64 kB, file 7 having a capacity of 64 kB, and file 8 having a capacity of 16 kB are written. FIG. 11 shows the state after the insertion.

  When the files 2, 5, and 8 are erased from this state, the logical blocks 83, 94, and 103 are logically erased.

  Next, when the file 9 having a capacity of 48 kB is written, the vacant logical block is generally filled from the front, so the data of the file 9 is written into the logical blocks 83, 94, 103.

  In the actual usage example shown in FIGS. 9 to 13, how the flash memory 103 is physically processed in the conventional write / erase process will be described with reference to FIGS.

  FIG. 21 corresponds to the state of FIG. Data of the logical group 10 is written to the physical block A1, data of the logical group 11 is written to the physical block A2, and data of the logical group 12 is written to the physical block A3. Physical blocks B1, B2, B3, C1, C2, and C3 exist as erased blocks.

  FIG. 22 shows the physical state in the flash memory 103 when the files 2, 5, and 8 are deleted and the state shown in FIG. 12 is obtained. By performing the same processing as described in FIG. 17, the data of physical blocks A1, A2, and A3 are replaced with data 0xFF in which only files 2, 5, and 8 are logically erased, and moved to physical blocks B1, B2, and B3. To do.

  Further, FIG. 23 shows a physical state in the flash memory 103 when the state shown in FIG. 13 after the file 9 is written is obtained. The file 9 enters the position where logical erase has been performed in the physical blocks B1, B2, B3, and has moved to the physical blocks C1, C2, C3.

  As described above, in the actual use examples shown in FIGS. 9 to 13, the conventional erasing / writing method writes data to six physical blocks (physical blocks B1, B2, B3, C1, C2, C3), It is necessary to physically erase the physical blocks (physical blocks A1, A2, A3, B1, B2, B3).

There exists patent document 1 as what discloses the same concept. This includes a description of a method for organizing data in a block related to data rewriting.
JP 2001-154909 A

  As described above, the conventional nonvolatile memory erasing / writing method requires erasing / writing more than the capacity of the logical block to be erased or written, the processing time is long, and the number of physical blocks required There were many issues.

  In order to solve the above-described problems, a nonvolatile memory device erasing method of the present invention includes a nonvolatile memory and a controller, and the nonvolatile memory includes a plurality of independently erasable physical blocks, and is erased from the outside. On the other hand, the remaining data excluding the data to be erased among the data of the physical block including the data to be erased is transferred to a new erased physical block.

  The non-volatile memory device writing method of the present invention includes a non-volatile memory and a controller, and the non-volatile memory includes a plurality of independently erasable physical blocks, and the physical block includes a plurality of independently writable multiple blocks. The controller consists of pages, and the controller manages the data in the nonvolatile memory by dividing it into logical groups with the same capacity unit as the physical block and logical blocks that include multiple logical groups. Is written to a physical page that has not been written to the physical block in which the data of the logical block including the data is written.

  The processing time for erasing data from the host can be shortened, the processing time for writing data from the host can be shortened, and the number of physical blocks in the flash memory required for writing processing is small As a result, the number of times of writing can be expected to be improved.

This onset Ming has a non-volatile memory, and a controller, in the non-volatile memory based on the logical address given from the outside, a non-volatile memory device which performs data writing, erasing and reading, the non The volatile memory is composed of a plurality of independently erasable physical blocks, each physical block is composed of a plurality of independently writable pages, and the controller erases data for a logical address given from the outside. The data to be erased is the data to be erased, the physical block of the non-volatile memory in which the data to be erased is written is determined as an old data block, and the data from the old data block is erased Only the remaining data excluding the target data is copied to a new erased physical block, and the newly erased data The erasing target data block which is a nonvolatile storage device is characterized in that leave the unwritten region of the same capacity.

In addition, the present invention is a nonvolatile memory device that includes a nonvolatile memory and a controller, and writes, erases, and reads data in and from the nonvolatile memory based on a logical address given from the outside, The non-volatile memory is composed of a plurality of independently erasable physical blocks, each physical block is composed of a plurality of independently writable pages, and the controller uses a logical address given from the outside as the physical block. A logical group having the same capacity and a plurality of logical blocks included in the logical group are managed, and when writing data to a logical address given from the outside, the data to be written is set as data to be written, Write the logical group containing the data to be written from the logical address of the data to be written The write target physical block is the physical block in which the data of the write target logical group is written as the target logical group, and the write target data is written to the unwritten physical page of the write target physical block. A nonvolatile memory device.

Further, the present invention comprises a plurality of independently erasable physical blocks, each physical block comprising a plurality of independently writable pages, and data writing based on a logical address given from the outside, A method for erasing a nonvolatile memory in which erasing and reading are performed. When erasing data for a logical address given from the outside, the erasing data is set as erasing target data, and the erasing target data is written The physical block of the non-volatile memory is determined as an old data block, and only the remaining data excluding the data to be erased from the data of the old data block is copied to a new erased physical block, and the new data block Non-volatile, characterized in that the data to be erased is left in an unwritten area of the same capacity in an erased physical block It is a method of erasing a memory.

Further, the present invention comprises a plurality of independently erasable physical blocks, each physical block comprising a plurality of independently writable pages, and data writing based on a logical address given from the outside, A non-volatile memory writing method in which erasure and reading are performed, and a logical address given from outside is divided into a logical group having the same capacity as the physical block and a plurality of logical blocks included in the logical group for management When writing data to a logical address given from the outside, the data to be written is set as the write target data, and the logical group including the write target data from the logical address of the write target data is set as the write target logical group. , The physical block in which the data of the write target logical group is written A write target physical block, the physical page is not written out of the write target physical block, which is the write target data and wherein the writing of the nonvolatile memory writing method.

  Hereinafter, a nonvolatile memory device and a nonvolatile memory erasing method and writing method according to embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
1 to 4 are a block diagram and a conceptual diagram showing configurations of a nonvolatile memory device and a flash memory according to the present embodiment, which are the same as those described in the conventional example, and a description thereof will be omitted.

  First, erasing of logical block data from the host 102 will be described.

  FIGS. 5 and 6 are explanatory diagrams and flowcharts showing the internal operation of the memory card 101 when the host 102 logically erases the data in the logical block 402 in which the memory card 101 is located. “Logically erasing” means that when the host 102 reads data from the memory card 101, all 0xFF data can be read. The flash memory 103 of the memory card 101, specifically, the host 102 is logically This represents a case where data in logical block 2 of group 0 is erased.

  First, at the writing start time of the flowchart, the data of the logical blocks 0 to 7 belonging to the logical group 0 has been written in the physical block A of the flash memory 103 in the memory card 101, and the physical block has been erased as a block for rewriting. B corresponds to the state of FIG.

  Next, in state 601, logical block 0 is read from read source physical block A and written to write destination physical block B. In state 602, logical block 1 is read from read source physical block A and written to write destination physical block B.

  The logical block 2 to be erased by the host 102 is not written into the write destination physical block B.

  Thereafter, the logical blocks 3 to 7 are read from the read source physical block A to the states 603 to 607 and written to the write destination physical block B sequentially. The state when the state 607 is completed is shown in FIG.

  Finally, in the state 608, the read source physical block A is physically erased and the process is terminated. The state at this time is shown in FIG.

  In this way, in the erasure process from the host 102, it is only necessary to write to all the physical pages except the page to be erased among the physical blocks to be written.

  The time required for this data erasing process is that the time required for reading one page is 265 μs (the busy time 25 μs until reading is possible + the data transfer time 240 μs for reading), and the time required for writing one page is 360 μs (writing Data transfer time 160 μs + time required for writing 200 μs). From 2 ms to erase one block, it takes 265 μs × 8 × 7 + 360 μs × 8 × 7 + 2 ms = 37000 μs, and takes 37000 μs.

  Next, data writing from the host 102 to the previously erased logical block will be described.

  FIGS. 7 and 8 are a diagram and a flowchart showing the internal operation of the memory card 101 when the host 102 writes data to the logical block 402 erased from the memory card 101 earlier.

  First, at the writing start time of the flowchart, 0, 1, 3 to 7 data which have been logically erased among the logical blocks 0 to 7 belonging to the logical group 0 are already written in the physical block B of the flash memory 103 in the memory card 101. Yes, an erased area having the same capacity as the logical block 2 remains. This corresponds to the state of FIG.

  Write processing for the write data corresponding to the logical block 2 sent from the host in the first state 801 is finished in the unwritten area of the write destination logical block B. The state at this time is shown in FIG.

  The time required for the writing process is 360 μs × 8 = 2880 μs, which is the same as the erasing time. That is, since it takes 2880 μs to write 16 KB, the writing speed is about 5.4 MB / sec.

  Based on the above erasure / write processing, as an actual use example as shown in FIGS. 9 to 13, there are writing of a plurality of files from the host 102, and then erasing some files and further writing new files. A process in the case of performing will be described.

  The details of FIGS. 9 to 13 are the same as those described in the conventional example, and thus the description thereof is omitted.

  In the actual use example shown in FIG. 9, how the flash memory 103 is physically processed in the conventional write / erase process will be described with reference to FIGS. 14 to 16.

  FIG. 14 corresponds to the state of FIG. Data of the logical group 10 is written to the physical block A1, data of the logical group 11 is written to the physical block A2, and data of the logical group 12 is written to the physical block A3. In addition, physical blocks B1, B2, and B3 exist as erased blocks.

  FIG. 15 shows the physical state in the flash memory 103 when the files 2, 5, and 8 are deleted and the state shown in FIG. 12 is obtained. By performing processing similar to the processing described with reference to FIG. 5, areas of the physical blocks A1, A2, and A3 having the same capacity as the files 2, 5, and 8 are left in the physical blocks B1, B2, and B3, respectively.

  FIG. 16 shows the physical state inside the flash memory 103 when the state shown in FIG. 13 after the file 9 is further written. The file 9 is written in the physical position that has not been written in the physical blocks B1, B2, and B3.

  As described above, in the actual use examples shown in FIGS. 9 to 13, in the conventional erasing and writing method, data is written in three physical blocks (physical blocks B1, B2, and B3), and three physical blocks (physical block A1). , A2, A3) need to be physically erased.

  As described above, according to the erase method of the nonvolatile storage device of the present invention, in response to a logical erase command from the host having a size smaller than the erase size of the flash memory mounted therein, the data to be logically erased from the host Data other than the logical erase target in the written physical block is moved to another physical block, and the data part to be logically erased is left in an unwritten erase state, and 0xFF data is written. Therefore, the time required for logical erasure can be increased at a higher speed than in the prior art.

  Further, according to the nonvolatile memory device writing method of the present invention, when data is written from the host, a new erased physical block is not written as in the prior art, but an unwritten area after logical erase is performed. By writing new write data, the write process can be performed much faster than before and the number of physical blocks of flash memory required for the write process can be reduced. .

  The nonvolatile memory device and nonvolatile memory erasing method and writing method according to the present invention can shorten the processing time for erasing data from the host, and shorten the processing time for writing data from the host. A nonvolatile memory device using a non-volatile memory such as a flash memory, which can reduce the number of physical blocks of the flash memory required for the writing process and can improve the rewrite life. It is useful as a method for erasing and writing a nonvolatile memory, a memory card using this method, an electronic device, and the like.

The block diagram which shows the structure of the memory card and host by embodiment of this invention The block diagram which shows the structure inside the flash memory used in the same embodiment The block diagram which shows the structure of the physical block of the flash memory used by the embodiment The block diagram which shows the structure of the logical map of the memory card by the embodiment Conceptual diagram showing logical erasure processing of the memory card according to the embodiment Flowchart showing logical erasure processing of the memory card according to the embodiment The conceptual diagram which shows the write-in process of the memory card by the embodiment Flowchart showing memory card write processing according to the embodiment Schematic diagram showing an example of erasing / writing data from a host to a memory card in the present invention Schematic diagram showing an example of erasing / writing data from a host to a memory card in the present invention Conceptual diagram showing an example of erasing and writing data from the host to a memory card Conceptual diagram showing an example of erasing and writing data from the host to a memory card Conceptual diagram showing an example of erasing and writing data from the host to a memory card Conceptual diagram showing processing for erasing / writing data from a host to a memory card according to the present invention. Conceptual diagram showing the process of erasing and writing data from the host to the memory card Conceptual diagram showing the process of erasing and writing data from the host to the memory card Conceptual diagram showing the logical erase process of a conventional memory card A flowchart showing the logical erase process of a conventional memory card Conceptual diagram showing the process of writing to a conventional memory card Flowchart showing conventional memory card writing process Conceptual diagram showing the process of erasing and writing data from the host to the memory card in the past Conceptual diagram showing the process of erasing and writing data from the host to the memory card Conceptual diagram showing the process of erasing and writing data from the host to the memory card

Explanation of symbols

101 memory card 102 host 103 flash memory 104 controller 105 erased table 106 logical-physical conversion table 201 physical block 301 physical page 302 partial physical block 401 logical group 402 logical block

Claims (4)

A non-volatile memory device having a non-volatile memory and a controller, and writing, erasing and reading data to and from the non-volatile memory based on a logical address given from outside,
Wherein the nonvolatile memory comprises a plurality of independently erasable physical block, before Symbol physics blocks Ri consists independently writable plurality of physical pages, the physical page is part physical block at a predetermined number of units Consisting of
When erasing data for a logical address given from the outside, the controller determines data to be erased as data to be erased and determines the physical block of the nonvolatile memory in which the data to be erased is written. As an old data block, only the remaining data excluding the data to be erased from the data of the old data block is copied in order from the top to the partial physical block of the new erased physical block, and the new erased physical block is copied. A non-volatile memory device, wherein an unwritten area having the same capacity as the data to be erased is left. Before SL controller includes a logical group is the same volume a logical address given from outside and the physical block, the managed by being divided into a plurality of logical blocks in the logical group, the data for the logical address given from the outside When writing, the data to be written is set as write target data, the logical group including the write target data is set as the write target logical group from the logical address of the write target data, and the data of the write target logical group is written. 2. The non-volatile storage device according to claim 1 , wherein the physical block that is stored is a write target physical block, and the write target data is written to an unwritten physical page of the write target physical block. . It is composed of a plurality of independently erasable physical blocks, each physical block is composed of a plurality of independently writable physical pages, the physical page is composed of partial physical blocks in a predetermined number of units, and is given from outside A nonvolatile memory writing / erasing method in which data is written, erased and read based on an address,
When erasing data for a logical address given from the outside, the data to be erased is the data to be erased, and the physical block of the nonvolatile memory in which the data to be erased is written is determined as the old data block Only the remaining data excluding the data to be erased from the data in the old data block is copied in order from the top to the partial physical block of the new erased physical block, and the data to be erased is written in the new erased physical block. A method for writing / erasing a non-volatile memory, wherein an unwritten area having the same capacity as that is left is left. A logical group of a logical address given from outside is the same capacity as the physical block, the managed by being divided into a plurality of logical blocks included in the logical group, when writing data to a logical address given from the outside The data to be written is set as the write target data, the logical group including the write target data is set as the write target logical group from the logical address of the write target data, and the physical data in which the data of the write target logical group is written 4. The non-volatile memory write / erase method according to claim 3 , wherein the write target physical block is a write target physical block, and the write target data is written to an unwritten physical page of the write target physical block. .

Images