Abstract:
A data protecting method for a memory, which comprising a volatile memory and a non-volatile memory for storing data and data protection information, comprises the following steps. Firstly, load the data protection information to the volatile memory from the non-volatile memory. Next, protect the data stored in the memory according to the data protection information stored in the volatile memory.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates in general to a data protecting method, and more particularly to a data protecting method for protecting data, stored in a memory array, according to protection information stored in a volatile memory. 
     2. Description of the Related Art 
     In the modern age, in which the technology changes with each passing day, non-volatile memories, such as flash memories, are widely used in various electronic products. Conventionally, a non-volatile memory is provided to store protection information so that modification protection may be performed on data stored in a flash memory. In some special occasions, however, the protection information stored in the non-volatile memory has to be rewritten at the high frequency. Thus, memory cells in the non-volatile memory may be damaged so that they cannot effectively record the protection information. Thus, it is an important direction in the industry to design a method of effectively recording the protection information. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a data protecting method of protecting data, stored in a memory, according to protection information stored in a volatile memory. The protection information stored in the volatile memory is loaded from a non-volatile memory. Compared with the conventional protection method, the data protecting method of the invention has the advantages of effectively recording the protection information and preventing the non-volatile memory from being damaged due to the high frequency rewriting. 
     According to a first aspect of the present invention, a data protecting method of a memory, which includes a volatile memory and a non-volatile memory for storing data and data protection information, is provided. The data protecting method comprising the following steps. Firstly, the data protection information is loaded to the volatile memory. Next, the data stored in the memory is protected according to the data protection information stored in the volatile memory. 
     According to a second aspect of the present invention, a memory is provided. The memory includes a volatile memory, a non-volatile memory, and a control circuit. The non-volatile memory stores data and data protection information. The control circuit loads the data protection information to the volatile memory. The control circuit protects the data stored in the memory according to the data protection information stored in the volatile memory. 
     The invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing a memory according to an embodiment of the invention. 
         FIG. 2  is a detailed schematic illustration of protection sectors in a non-volatile memory NVM of  FIG. 1 . 
         FIG. 3  is a flow chart showing a data protecting method according to the embodiment of the invention. 
         FIG. 4  is a detailed flow chart showing the step (b) of  FIG. 3 . 
         FIG. 5  is a partial flow chart showing the data protecting method according to the embodiment of the invention. 
         FIG. 6  is a partial flow chart showing the data protecting method according to the embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a block diagram showing a memory  1  according to an embodiment of the invention. Referring to  FIG. 1 , the memory  1  includes a non-volatile memory NVM, a control circuit  20  and a volatile memory  30 . The non-volatile memory NVM includes many memory sectors for storing corresponding data. The non-volatile memory NVM further stores data protection information Sp corresponding to the data stored in the non-volatile memory NVM. 
     In one example, the non-volatile memory NVM is implemented by a memory array  10 , for example. The memory  1  further includes, for example, a row decoder (X-decoder)  42 , a column decoder (Y-decoder)  44 , a sense amplifier  46  and an address generator  48 . The address generator  48  generates a row address signal Adr and a column address signal Adc for respectively driving the row decoder  42  and the column decoder  44  to enable the non-volatile memory NVM to provide corresponding current signals. The sense amplifier  46  senses the current signals to correspondingly output the data protection information Sp. 
     The control circuit  20  receives the data protection information Sp provided by the sense amplifier  46  and correspondingly loads the data protection information Sp into the volatile memory  30 . In one example, the volatile memory  30  is implemented by, for example, a register in the memory  1 . 
     The control circuit  20  further protects the data stored in the non-volatile memory NVM according to the data protection information Sp in the volatile memory  30 . In one operation example, the control circuit  20  obtains that one specific memory sector in the non-volatile memory NVM is protected in response to the data protection information Sp. Thus, if the control circuit  20  receives a data change command, which indicates that a data change operation is performed on the specific memory sector being protected, then the control circuit  20  cannot perform the corresponding data change operation. In one example, the control circuit  20  further correspondingly triggers a protection operation event to notify the user that the specific memory sector is in a protected state. 
       FIG. 2  is a detailed schematic illustration of protection sectors in the non-volatile memory NVM of  FIG. 1 . For example, the non-volatile memory NVM has protection information memory sectors BPS, SPS and CLS, and the data protection information Sp includes first protection information, second protection information and protection selecting information respectively stored in the protection information memory sectors BPS, SPS and CLS. 
     In one example, the first and second protection information is respectively block protection information and sector protection information. 
     For example, the non-volatile memory NVM includes 128 memory sectors. The protection information memory sector BPS stores the block protection information with four bits of data. For example, when the block protection information has the values (1000) 2 , (0111) 2 , (0110) 2 , (0101) 2 , (0100) 2 , (0011) 2 , (0010) 2  and (0001) 2 , the control circuit  20  correspondingly regards the whole 128 memory sectors, the former 64 memory sectors, the former 32 memory sectors, the former 16 memory sectors, the former 8 memory sectors, the former 4 memory sectors, the former 2 memory sectors and the first memory sector of the 128 memory sectors as the memory sector being protected. When the block protection information has the value (0000) 2 , the control circuit  20  regards the 128 memory sectors as the memory sectors that are not protected. 
     In another example, the protection information memory sector SPS stores, for example, sector protection information with 128 bits of data respectively corresponding to the 128 memory sectors in the non-volatile memory NVM. When each of the 128 bits of data has the value 0, it represents that the memory sector corresponding to each bit of data is not being protected. When each of the 128 bits of data has the value 1, it represents that the memory sector corresponding to each bit of data is protected. 
     The control circuit  20  reads the protection selecting information to read one of the block protection information stored in the protection information memory sector BPS and the sector protection information stored in the protection information memory sector SPS. The control circuit  20  stores the read block protection information/sector protection information in the volatile memory  30 . Thus, the control circuit  20  can protect the data stored in the non-volatile memory NVM according to the block protection information/the sector protection information stored in the volatile memory  30 . 
     The data stored in the protection information memory sectors BPS, SPS and CLS of the non-volatile memory NVM are programmable. Thus, the user can selectively protect the data stored in the non-volatile memory NVM by way of sector protection or block protection by editing the information stored in the protection information memory sectors BPS, SPS and CLS. 
     The control circuit  20  further performs the data programming and reading operations on the non-volatile memory NVM and the volatile memory  30  in response to an input command Cmd. 
     In one operation example, the control circuit  20  modifies the data protection information stored in the volatile memory  30  in response to a temporary modification command. Thus, the control circuit  20  can protect the data stored in the non-volatile memory NVM according to the modified data protection information stored in the volatile memory  30 . 
     In another operation example, the control circuit  20  performs a permanent modification operation on the data protection information stored in the non-volatile memory NVM in response to a permanent modification command. After the operation of modifying the information stored in the non-volatile memory NVM, the control circuit  20  provides the data protection information Sp, obtained after the permanent modification operation, to the volatile memory  30  through, for example, the circuits, such as the row decoder  42 , the column decoder  44 , the sense amplifier  46  and the address generator  48 , and thus protects the data stored in the non-volatile memory NVM based on the permanent modified data protection information stored in the volatile memory  30 . 
       FIG. 3  is a flow chart showing a data protecting method according to the embodiment of the invention. First, as shown in step (a), the control circuit  20  loads the data protection information Sp stored in the non-volatile memory NVM to the volatile memory  30 . Thereafter, as shown in step (b), the control circuit  20  protects the data stored in the non-volatile memory NVM according to the data protection information stored in the volatile memory  30 . 
       FIG. 4  is a detailed flow chart showing the step (b) of  FIG. 3 . In one example, the step (b) includes steps (b 1 ) to (b 4 ). As shown in the step (b 1 ), the control circuit  20  receives the data change command, which corresponds to one specific memory sector in the non-volatile memory NVM, for example. 
     Next, as shown in the step (b 2 ), the control circuit  20  determines the protection solution currently applied to the non-volatile memory NVM according to the protection selecting information stored in the corresponding volatile memory  30 . If the protection solution currently applied to the non-volatile memory NVM is the sector protection, then the step (b 3 ) is performed, and the control circuit  20  judges whether or not the specific memory sector is being protected according to the data protection information stored in the volatile memory  30  loaded from the data protection information stored in the protection information memory sector SPS of the non-volatile memory NVM. If yes, step (b 5 ) is performed, and the control circuit  20  triggers the protection operation event to notify the user that the specific memory sector is being protected. If not, step (b 6 ) is performed and the control circuit  20  changes the data stored in the specific memory sector in response to the data change command. 
     In another example, if the protection solution currently applied to the non-volatile memory NVM in the step (b 2 ) is the block protection, then the step (b 4 ) is performed, and the control circuit  20  judges whether or not the specific memory block is being protected according to the data protection information stored in the volatile memory  30  loaded from the data protection information stored in the protection information memory sector BPS of the non-volatile memory NVM. If yes, step (b 5 ) is performed, and the control circuit  20  triggers the protection operation event to notify the user that the specific memory block is being protected. If not, step (b 6 ) is performed and the control circuit  20  changes the data stored in the specific memory block in response to the data change command. 
     The data protecting method of this embodiment further includes, for example, the step (c), as shown in  FIG. 5 . In the step (c), the control circuit  20  performs a temporary modification operation on the data protection information stored in the volatile memory  30  in response to the temporary modification command. In an example, the data protection information further includes the protection selecting information. In one example, the step (c) is performed after the step (b) is performed. 
     The data protecting method of this embodiment further includes, for example, steps (c 1 ′) and (c 2 ′), as shown in  FIG. 6 . In the step (c 1 ′), the control circuit  20  performs the permanent modification operation on the data protection information Sp stored in the non-volatile memory NVM in response to the permanent modification command. Next, in the step (c 2 ′), the control circuit  20  loads the data protection information Sp, obtained after the permanent modification operation, into the volatile memory  30 , and thus protects the data stored in the non-volatile memory NVM. In one example, the steps (c 1 ′) and (c 2 ′) are performed after the step (b) is performed. 
     The data protecting method of this embodiment protects the data stored in the non-volatile memory via the protection information stored in the volatile memory. The protection information stored in the volatile memory is loaded from the non-volatile memory. Thus, compared with the conventional protection method, the data protecting method of this embodiment has the advantages of effectively recording the protection information and preventing the non-volatile memory, which should be rewritten at the high frequency, from being damaged. 
     In addition, the data protecting method of this embodiment may further select one of the first and second data protection solutions as the data protection solution for the non-volatile memory by reading the protection selecting information stored in the non-volatile memory. The user may select one of the first and second data protection solutions more flexibly to protect the data stored in the non-volatile memory by programming the protection selecting information or temporarily changes protection selecting information stored in the volatile memory. Thus, compared with the conventional protection method, the data protecting method of this embodiment has the advantages of protecting the data stored in the non-volatile memory using different types of data protection solutions more flexibly. 
     While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.