TWI490870B - Data storage device and data maintenance method thereof - Google Patents

Description

Data storage device and data maintenance method thereof

The invention relates to a data maintenance method for a memory device; in particular, to a data maintenance method for automatically monitoring parameters of a flash memory.

Flash memory is a popular non-volatile data storage device that is electrically erased and programmed. For example, NAND FLASH, which is not a gate type, is often used as a memory card, a universal flash memory device, a solid state drive (SSD), and an embedded flash. Memory module (eMMC)...etc.

A flash memory (eg, NAND FLASH) storage array includes a plurality of blocks, wherein a floating gate transistor can be used to form a flash memory. A floating gate in a floating gate transistor that captures charge to store data. However, the charge stored in the floating gate can be lost from the floating gate due to the operation of the flash memory and various environmental parameters, resulting in Dara retention problems.

The invention provides a data storage device. The data storage device includes a flash memory, a temperature sensing device, and a controller. The flash memory has a plurality of blocks, each block having a plurality of pages. The temperature sensing device is configured to detect ambient temperature in the surroundings to generate temperature parameters that vary with ambient temperature. control The controller is configured to perform a first maintenance procedure after the data storage device is powered on for a predetermined time. In the first maintenance procedure, the controller reads the temperature sensing device to obtain a first temperature parameter, and according to a first The predetermined condition determines a first time length to perform a second maintenance procedure, wherein the first predetermined condition includes a first temperature parameter, and the controller is further configured to perform the second maintenance after the first time length of the end of the first maintenance program program. In the first maintenance procedure, the controller is further configured to perform a first block scan on the block to obtain a plurality of first error bit numbers respectively corresponding to the block, and corresponding to a threshold value exceeding a predetermined error bit. The block of the first error bit number is updated.

In the second maintenance procedure, the controller reads the temperature sensing device to obtain a second temperature parameter, and determines a second time length according to a second predetermined condition and a first history to perform a third maintenance procedure, wherein The second predetermined condition includes a second temperature parameter, and the first history record includes the first number of error bits and the number of blocks that were updated in the first maintenance program. In addition, in the second maintenance procedure, the controller is further configured to determine a first error bit threshold according to the first history record, perform a second block scan on the block to obtain a complex second corresponding to the block respectively. The number of error bits is updated and the block corresponding to the second number of error bits exceeding the threshold of the first error bit is updated.

It should be noted that the first predetermined condition and the second condition further include the time when the data storage device was last accessed by a host, the time when the data storage device is powered on, and/or the number of times the block is erased. In another preset time of the embodiment, the controller is further configured to read the temperature sensing device to obtain the current temperature parameter every predetermined cycle, and adjust the start execution according to the current temperature parameter read. A time to maintain the program.

The invention also provides a data maintenance method, which is suitable for a data storage device having a flash memory, wherein the flash memory has a plurality of blocks, each block having a plurality of pages. The data maintenance method includes: after the data storage device is powered on for a preset time, executing a first maintenance program; in the first maintenance program, reading a temperature sensing device to obtain a first corresponding to ambient temperature a temperature parameter; in the first maintenance procedure, determining a first time length according to a first predetermined condition to perform a second maintenance procedure, wherein the first predetermined condition includes a first temperature parameter; and the first block is performed on the block Scanning to obtain a plurality of first error bit numbers respectively corresponding to the block; updating the block corresponding to the first error bit number exceeding a predetermined error bit threshold; and ending at the first maintenance program After the first length of time, the second maintenance procedure is performed.

The second maintenance program further includes: reading the temperature sensing device to obtain a second temperature parameter corresponding to the ambient temperature; determining a second time length according to a second predetermined condition and a first historical record to perform a first a maintenance program; determining a first error bit threshold according to the first history; performing a second block scan on the block to obtain a plurality of second error bits respectively corresponding to the block; and corresponding to exceeding The block of the second error bit number of the first error bit threshold is updated, wherein the second predetermined condition includes the second temperature parameter, and the first history record includes the first error bit number and the first maintenance procedure The number of blocks that have been updated.

In another embodiment, the data maintenance method further includes: in the preset time, the controller is further configured to read the temperature sensing device to obtain the current temperature parameter every predetermined period; and according to the current reading The temperature parameter adjusts the time to start the first maintenance program.

100‧‧‧Electronic system

120‧‧‧Host

140‧‧‧Data storage device

160‧‧‧ Controller

162‧‧‧ arithmetic unit

164‧‧‧Permanent memory

165‧‧‧ random access memory

166‧‧‧Timer

180‧‧‧Flash memory

190‧‧‧Temperature sensing device

S202~S206, S300~S306‧‧‧ steps

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of an electronic system in accordance with one embodiment of the present invention.

2 is a flow chart of a data maintenance method of an embodiment of the present invention.

Figure 3 is a flow chart of a data maintenance method of another embodiment of the present invention.

The apparatus and method of use of various embodiments of the present invention are discussed in detail below. However, it is to be noted that many of the possible inventive concepts provided by the present invention can be implemented in various specific ranges. These specific examples are only intended to illustrate the apparatus and methods of use of the present invention, but are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of an electronic system in accordance with one embodiment of the present invention. The electronic system 100 includes a host 120 and a data storage device 140. The data storage device 140 includes a controller 160, a flash memory 180, and a temperature sensing device 190, and is operable according to commands issued by the host 120. The controller 160 includes an arithmetic unit 162, a permanent memory (e.g., read only memory ROM) 164, a random access memory 165, and a timing device 166. The permanent memory 164 and the stored code and data constitute a firmware, which is executed by the operation unit 162, so that the controller 160 controls the flash memory 180 based on the firmware. For example, the controller 160 can perform access to the flash memory 180 according to the command of the host 120, and automatically execute the maintenance program. It is to be noted that, in one embodiment of the present invention, the maintenance program is repeatedly executed in the background, but the present invention is not limited thereto. For example, the controller 160 executes the maintenance program when it is idle, and interrupts the maintenance performed when receiving the action command from the host 120. program. Flash memory 180 has a plurality of blocks, each block having a plurality of pages. The timing device 166 is used to record the time when the data storage device 180 is powered on, the time between the program and the program, and the like. The temperature sensing device 190 is configured to detect an ambient temperature around the data storage device 140 to generate a temperature parameter that varies with ambient temperature. In the present embodiment, the temperature sensing device 190 is disposed adjacent to the flash memory 180 in the data storage device 140 for detecting the ambient temperature around the flash memory 180, but the invention is not limited thereto. In another embodiment, the temperature sensing device 190 can also be disposed outside the data storage device 140 for detecting the ambient temperature around the data storage device 140.

In addition, the flash memory 180 is further configured to store at least one parameter comparison table and a scan condition table. In an embodiment, the parameter comparison table is used to store the time interval between the execution of the next maintenance program at different ambient temperatures, but the invention is not limited thereto. In other embodiments, the parameter comparison table also includes different environments, different number of error bits, different numbers of updated blocks, different times when the data storage device 140 is last accessed by a host 120, and a data storage device. The time between the execution of the next maintenance procedure at 140 different times of power-up and/or the number of times the block is erased. The scan condition table is used to store different number of scan conditions corresponding to different error bit numbers and/or updated blocks. For example, the scan condition may be an error bit threshold, but the invention is not limited thereto. In other embodiments, the scanning conditions may also be different error correction codes and the like. In another embodiment, the flash memory 180 is configured to store a parameter function and a scan condition function. In this embodiment, the time interval between execution of the next maintenance program is determined by the parameter function. For example, depending on the ambient temperature, the parameter function can be calculated to obtain different executions for the next maintenance process. The time interval between the sequences, but the invention is not limited thereto. In other embodiments, the parameter function may also be based on different ambient temperatures, different number of error bits, different numbers of updated blocks, different times when the data storage device 140 was last accessed by a host 120, and a data storage device. The different times of power-on of 140 and/or the number of times the block is erased determines the time interval between the execution of the next maintenance procedure. In addition, the scanning condition function is used to determine different scanning conditions according to different number of error bits and/or different numbers of updated blocks. It is worth noting that the higher the ambient temperature, the number of error bits, the number of update blocks, the time when the data storage device 140 is powered on, and the number of times the block is erased, corresponding to the shorter interval between the maintenance procedures. time. The higher the number of error bits and the number of update blocks, the lower the error bit threshold.

In an embodiment, the controller 160 is configured to perform a first maintenance procedure after the data storage device 140 is powered on for a predetermined time. In the present embodiment, the preset time is a predetermined time, but the present invention is not limited thereto. For example, the preset time may be 4 minutes or 5 minutes, and the present invention is not limited thereto. In the first maintenance procedure, the controller 160 reads the temperature sensing device 190 to obtain a first temperature parameter, determines a first time length according to a first predetermined condition, and performs a first block scan on the block. The number of first error bits corresponding to the plurality of blocks respectively is obtained. In an embodiment, the first predetermined condition includes the first temperature parameter, but the invention is not limited thereto. In other embodiments, the first predetermined condition may also include the time when the data storage device 140 was last accessed by a host 120, the time when the data storage device 140 was powered on, and/or the number of times the block was erased. The controller 160 may determine the first time length according to the parameter comparison table or the parameter function in the first maintenance program to execute the second maintenance process after the first maintenance program ends the first time length sequence. It is worth noting that the parameters in the first established condition are the current data. Therefore, the parameters in the first maintenance program may be different from the parameters in the second maintenance program, and the parameters in the second maintenance program may be different from the parameters in the third maintenance program. In some cases, the parameters in different maintenance procedures may be the same. For example, when the host 120 does not erase the flash memory 180 between the second maintenance program and the third maintenance program, the "block" in the second maintenance program and the third maintenance program is erased. The number of times is the same. On the other hand, when the host 120 erases the flash memory 180 between the second maintenance program and the third maintenance program, the "number of times the block is erased" in the second maintenance program and the third maintenance program is not the same. It should be noted that the controller 160 is further configured to update the block corresponding to the first error bit number exceeding a predetermined error bit threshold. In the present embodiment, the threshold value of the predetermined error bit is a predetermined threshold value, but the present invention is not limited thereto.

In another embodiment, in a preset time, the controller 160 is further configured to read the temperature sensing device 190 every other predetermined period to obtain the current temperature parameter, and according to the current temperature parameter read, Adjust the time to start the first maintenance program. In other words, starting from the power-on of the data storage device 140, the controller 160 is further configured to read the temperature sensing device 190 every other predetermined period to obtain the current temperature parameter, and according to the current temperature parameter read by The parameter comparison table or the parameter function determines the time when the first maintenance program is started, wherein the predetermined period is less than the preset time. For example, the preset time may be 1 second or 2 seconds, etc., and the present invention is not limited thereto. When it is determined that the time to start executing the first maintenance program is less than the original preset time, the controller 160 is further configured to modify the preset time according to the determined time. For example, the preset time is 5 minutes and the established period is 2 second. Within 5 minutes from the start of powering up the data storage device 140, the controller 160 reads the temperature sensing device 190 every 2 seconds to obtain the current temperature parameter, and decides to start according to the current temperature parameter read. The time to execute the first maintenance program. For example, when the controller 160 determines that the first maintenance program should be executed after the data storage device 140 is powered on for 6 minutes (greater than the preset time) according to the current temperature parameter read, the controller 160 ignores the determined time. And repeat the above steps again after 2 seconds until the preset time is over. When the controller 160 determines that the first maintenance program should be executed after the data storage device 140 is powered on for 3 minutes (less than the original preset time) according to the current temperature parameter read, the controller 160 modifies the preset time to 3 minutes. And the above steps are repeated again after 2 seconds until the preset time is over. In other words, the controller 160 changes the first maintenance program to be performed after the data storage device 140 is powered on for 3 minutes, and so on.

The controller 160 is further configured to execute the second maintenance procedure after the first length of time of the end of the first maintenance program. In the second maintenance procedure, the controller 160 reads the temperature sensing device 190 to obtain a second temperature parameter, determines a second time length according to a second predetermined condition, and a first history to perform a third maintenance procedure. And determining a first error bit threshold based on the first history record and thereby performing a second block scan on the block. In an embodiment, the second predetermined condition includes the second temperature parameter, and the first history record includes the first number of error bits and the number of blocks updated in the first maintenance program, but the invention is not limited thereto. In other embodiments, the second predetermined condition may also include the time when the data storage device 140 was last accessed by a host 120, the time when the data storage device 140 was powered on, and/or the number of times the block was erased. The controller 160 may determine the second time length according to the parameter comparison table or the parameter function in the second maintenance program to After the second maintenance program ends the second length of time, the third maintenance procedure is executed. It is worth noting that the parameters in the first predetermined condition are the current data, and the third maintenance procedure is the same as the operation of the second maintenance program. Similarly, the third maintenance program also determines a third time length to determine when to start executing the fourth maintenance procedure, and determines a second error bit threshold to perform a third block scan on the block, fourth. The maintenance procedure is also the same as the second maintenance procedure, and so on. It should be noted that the controller 160 is further configured to update a block corresponding to the second error bit number exceeding a first error bit threshold.

It should be noted that when the controller 160 can store the result of the block scan (for example, the number of error bits or the number of blocks updated) or the erased number of the block, etc., to the flash memory. The specific block in the body 180 is operated to provide a maintenance program, but the present invention is not limited thereto. During the block scan process, the controller 160 sequentially scans each block in the flash memory 180 to obtain the number of error bits corresponding to each block, respectively. In detail, the controller 160 sequentially reads each block in the flash memory 180, and obtains error correction corresponding to the read block in the process of reading the block (Error Correction; ECC) The number of error bits. Then, the controller 160 is further configured to update a block corresponding to the number of error bits exceeding the threshold, such as a predetermined error bit threshold and a first error bit threshold, a second error bit threshold, and the like. The action of "update", for example, the controller reads out the data in the block, and after the data is verified, it is restored to a block of the flash memory. It is worth noting that the error bit threshold is less than or equal to the maximum value of the error bits allowed by error verification (ECC). For example, when error verification can only correct error bits less than 43 bits, the error threshold can be 35bit or 38bit, but this The invention is not limited to this. Those skilled in the art will be able to design the error threshold to be less than or equal to the maximum value of the error bits allowed by error verification (ECC), depending on the error verification (ECC) used, by the teachings of the present invention.

2 is a flow chart of a data maintenance method of an embodiment of the present invention. The data maintenance method is applied to the data storage device 140 shown in FIG. The flow begins in step S202.

In step S202, the controller 160 is configured to start performing the first maintenance procedure, such as the first maintenance procedure described above, after the data storage device 140 is powered on for a predetermined time. In the present embodiment, the preset time is a predetermined time, but the present invention is not limited thereto. For example, the preset time may be 4 minutes or 5 minutes, and the present invention is not limited thereto. In the first maintenance procedure, the controller 160 reads the temperature sensing device 190 to obtain a current temperature parameter, determines a time length according to a first predetermined condition, and performs a block scan on the block to obtain respectively corresponding to The number of complex error bits in the block. In an embodiment, the first predetermined condition includes a current temperature parameter, but the invention is not limited thereto. In other embodiments, the first predetermined condition may also include the time when the data storage device 140 was last accessed by a host 120, the time when the data storage device 140 was powered on, and/or the number of times the block was erased. The controller 160 may determine the length of time according to the parameter comparison table or the parameter function in the first maintenance program to execute the periodic maintenance program after the first maintenance program ends the length of time, for example, the first maintenance program, the second Maintenance procedures, third maintenance procedures, and more. It is worth noting that the parameters in the first established condition are the current data. It should be noted that the controller 160 is further configured to update the block corresponding to the first error bit number exceeding a predetermined error bit threshold. In this embodiment, the threshold value of the predetermined error bit is a predetermined threshold. However, the invention is not limited thereto.

Then, after a length of time, the controller 160 begins executing the subsequent periodic maintenance procedure. For example, after the first maintenance program ends one of the lengths of time determined in step S202, the controller 160 executes the second maintenance program. First, in step S204, the controller 160 reads the temperature sensing device 190 to obtain the current temperature parameter, determines a further time length according to the current established condition and a historical record to perform a next cycle maintenance procedure, and determines according to the historical record. An error bit threshold. In an embodiment, the current established condition includes the current temperature parameter, and the history record includes the number of error bits of the last block scan and the number of blocks that were updated in the last maintenance procedure, but the invention is not limited thereto. In other embodiments, the current established conditions may also include the time when the data storage device 140 was last accessed by a host 120, the time at which the data storage device 140 was powered on, and/or the number of times the block was erased. The controller 160 may determine the length of time in the maintenance program according to the parameter comparison table or the parameter function to execute the next maintenance procedure after the current maintenance program ends the length of time.

Next, in step S206, the controller 160 performs a block scan on the block according to the error bit threshold, wherein the controller 160 performs block scan on the block to obtain the number of complex error bits respectively corresponding to the block. And update the block corresponding to the number of error bits exceeding the critical bit threshold. Next, the flow returns to step S204.

Figure 3 is a flow chart of a data maintenance method of an embodiment of the present invention. The data maintenance method is applied to the data storage device 140 shown in FIG. The flow begins in step S300. It is to be noted that the data maintenance method shown in FIG. 3 is similar to the data maintenance method shown in FIG. 2 except for step S300. therefore, For the steps S302-S306, refer to the description of steps S202-S206, and details are not described herein again.

In step S300, the controller 160 is configured to read the temperature sensing device 190 to obtain the current temperature parameter every other predetermined period from the power-on of the data storage device 140 for a predetermined period of time, and according to the read The current temperature parameter adjusts the preset time for the first maintenance program to be executed. In other words, starting from the power-on of the data storage device 140, the controller 160 is further configured to read the temperature sensing device 190 every other predetermined period to obtain the current temperature parameter, and according to the current temperature parameter read by The parameter correspondence table or parameter interpretation formula determines the time when the first maintenance program is started, wherein the predetermined period is less than the preset time. For example, the preset time may be 1 second or 2 seconds, etc., and the present invention is not limited thereto. When it is determined that the time for starting the execution of the first maintenance program is less than the original preset time, the controller 160 is further configured to modify the preset time according to the determined time. For example, the preset time is 5 minutes and the established period is 2 seconds. Within 5 minutes from the start of powering up the data storage device 140, the controller 160 reads the temperature sensing device 190 every 2 seconds to obtain the current temperature parameter, and decides to start according to the current temperature parameter read. The time to perform the first maintenance procedure. For example, when the controller 160 determines that the first maintenance procedure should be performed after the data storage device 140 is powered on for 6 minutes (greater than the preset time) according to the current temperature parameter read, the controller 160 ignores the determined decision. Time, and repeat the above steps again after 2 seconds until the preset time is over. When the controller 160 determines that the first maintenance procedure should be performed after the data storage device 140 is powered on for 3 minutes (less than the original preset time) according to the current temperature parameter read, the controller 160 modifies the preset time to 3 The above steps are repeated again after 2 seconds and until the preset time is over. In other words, the controller 160 changes the first maintenance program to the data storage device. 140 is powered on after 3 minutes, and so on.

As can be seen from the above, the data storage device 140 and the data maintenance method can automatically scan the block according to the current temperature and update the block.

The method of the invention, or a particular type or portion thereof, may exist in the form of a code. The code can be stored in a physical medium such as a floppy disk, a CD, a hard disk, or any other machine readable (such as computer readable) storage medium, or is not limited to an external form of computer program product, wherein When the code is loaded and executed by a machine, such as a computer, the machine becomes a device for participating in the present invention. The code can also be transmitted via some transmission medium, such as a wire or cable, fiber optics, or any transmission type, where the machine becomes part of the program when it is received, loaded, and executed by a machine, such as a computer. Invented device. When implemented in a general purpose processing unit, the code combination processing unit provides a unique means of operation similar to application specific logic.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention.

100‧‧‧Electronic system

120‧‧‧Host

140‧‧‧Data storage device

160‧‧‧ Controller

162‧‧‧ arithmetic unit

164‧‧‧Permanent memory

165‧‧‧ random access memory

166‧‧‧Timer

180‧‧‧Flash memory

190‧‧‧Temperature sensing device

Claims (14)

A data storage device includes: a flash memory having a plurality of blocks, each of the blocks having a plurality of pages; and a controller for performing a first time after the data storage device is powered on for a predetermined time a maintenance program, in the first maintenance program, the controller is further configured to perform a first block scan on the block to obtain a plurality of first error bit numbers respectively corresponding to the block, and corresponding to exceeding Determining the block of the first error bit number of a predetermined error bit threshold and updating the time according to the first number of error bits and the number of the blocks updated in the first maintenance procedure Length to determine when other maintenance procedures begin. According to the data storage device of claim 1, further comprising a temperature sensing device for detecting ambient temperature to generate a temperature parameter that varies with ambient temperature, wherein in the first maintenance program, the above The controller reads the temperature sensing device to obtain a temperature parameter, and the controller is further configured to determine the length of time according to the temperature parameter. According to the data storage device of claim 2, wherein in the preset time, the controller is further configured to read the temperature sensing device to obtain the current temperature parameter every other predetermined period, and according to the read Take the current temperature parameter and adjust the time to start the above first maintenance procedure. The data storage device of claim 1, wherein the controller is further configured to determine a first error bit according to the first number of error bits and the number of the blocks updated in the first maintenance program. Threshold value, Performing a second block scan on the block to obtain a plurality of second error bit numbers respectively corresponding to the block, and corresponding to the second error bit number exceeding the threshold value of the first error bit The above blocks are updated. The data storage device of claim 1, wherein the controller is further configured to determine the length of time according to a time when the data storage device is last accessed by a host. According to the data storage device of claim 1, wherein the controller is further configured to determine the length of time according to the time when the data storage device is powered on. The data storage device of claim 1, wherein the controller is further configured to determine the length of time according to the number of times the block is erased. A data maintenance method is applicable to a data storage device having a flash memory, wherein the flash memory has a plurality of blocks, each of the blocks has a plurality of pages, and the data maintenance method comprises: the data storage device After the power-on for a preset time, performing a first maintenance procedure, where the first maintenance procedure includes: performing, in the first maintenance procedure, a first block scan on the block to obtain respectively corresponding to the block a plurality of first error bit numbers; in the first maintenance procedure, updating the block corresponding to the first error bit number exceeding a predetermined error bit threshold; and Based on the first number of error bits and the number of the blocks updated in the first maintenance program, a length of time is determined to determine the time at which a second maintenance program begins. According to the data maintenance method of claim 8, the method further comprises: reading a temperature sensing device to obtain a temperature parameter corresponding to the surrounding ambient temperature, wherein the step of determining the length of time further comprises determining the time according to the temperature parameter. length. According to the data maintenance method of claim 9 of the patent application scope, the method further includes: reading the temperature sensing device to obtain the current temperature parameter every other predetermined period in the preset time; and reading according to the The current temperature parameter adjusts the time at which the first maintenance procedure described above is executed. According to the data maintenance method of claim 8, wherein the second maintenance program further includes: determining a first according to the first error bit number and the number of the blocks updated in the first maintenance program. An error bit threshold value; performing a second block scan on the block to obtain a plurality of second error bit numbers respectively corresponding to the block; and the foregoing corresponding to the threshold value exceeding the first error bit The above blocks of the second error bit number are updated. According to the data maintenance method of claim 8, wherein the step of determining the length of time further comprises determining the length of time according to the time when the data storage device is last accessed by a host. According to the data maintenance method of Article 8 of the patent application scope, the above time is determined The step of length further includes determining the length of time according to the time when the data storage device is powered on. According to the data maintenance method of claim 8, wherein the step of determining the length of time further comprises determining the length of time according to the number of times the block is erased.