JP2004213695A - Nonvolatile memory, memory card using it, information processor and software write protection control method for nonvolatile memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonvolatile memory exhibiting nonvolatile software write protection and to provide a system technique using it in a memory card and an information processor using the nonvolatile memory without a write protection function. <P>SOLUTION: A flash memory card 1 uses the rewritable nonvolatile memory without a nonvolatile software write protection function. This memory card comprises a batch electrical erasure and a writable flash memory 2, a reset IC 3 issuing a power-on reset signal when applying power, and a card controller 4 controlling the devices and the nonvolatile memory and a memory card interface. The flash memory 2 is so formed that a write protection storage register 5 writing an address of an area intended to perform the write protection is set in an attribute region and a protection range is set from the system. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a non-volatile memory and a system technology using the same, and in particular, to a system using a rewritable non-volatile memory without a non-volatile software write protect function, for example, a general information processing device and a general memory card, and a non-volatile memory. The present invention relates to a non-volatile memory capable of performing non-volatile software write protection in a memory device, a memory card using the same, an information processing apparatus, and a technique effective when applied to a non-volatile memory software write protection control method.

  For example, as a Flash memory card using a Flash memory (flash EEPROM) as a non-volatile memory and having a non-volatile software write protection function, Series 2+ of Intel Corporation has been commercialized. This uses a Flash memory manufactured by Intel Corporation, and the Flash memory itself has a write protection function for each erase block.

  The software write protect function is a word for a hardware write protect function using a write protect switch or the like, and is software that means that the user (system) can arbitrarily set a write protect area in the Flash memory area. Performing write protection by this software can be defined as software write protection.

  By the way, in the above-mentioned Flash memory card, since the Flash memory itself has a write protect function, software write protection is possible. For example, a Flash memory without a write protect function in an arbitrary area is used. In the memory card used, rewritable nonvolatile software write protection of the write protection area is not possible.

  Therefore, an object of the present invention is to provide a memory card and an information processing device using a non-volatile memory such as a flash memory without a write protection function by setting a non-volatile memory write protection storage register in the non-volatile memory. And a memory card using the same, an information processing apparatus, and a method for controlling software write protection of the nonvolatile memory.

  The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  The following is a brief description of an outline of typical inventions disclosed in the present application.

  That is, the non-volatile memory of the present invention is applied to a rewritable non-volatile memory having no non-volatile software write protection function. This is to set a write protection storage register for writing an address of an arbitrary write protection area in units of erasing.

  In this case, the setting of the write protection area can be changed from the beginning to the end of the nonvolatile memory, from the end to the end, from the end to the end, or from the arbitrary to the arbitrary erase unit. Can be changed in block units, and is applied to, for example, a flash memory.

  Further, a memory card of the present invention uses the nonvolatile memory, and comprises the nonvolatile memory and a card controller which controls at least between the nonvolatile memory and the memory card interface.

  Further, an information processing apparatus according to the present invention uses the nonvolatile memory, and includes the nonvolatile memory, and at least a central processing unit and its peripheral devices.

  Also, the software write protection control method for a nonvolatile memory according to the present invention writes an address of an arbitrary write protection area to a write protection storage register in the nonvolatile memory, and writes an address accessed by a user using the address. It is determined whether or not the data is within the protection area, and nonvolatile software write protection control is performed.

(Action)
According to the above-described nonvolatile memory, the memory card using the same, the information processing apparatus, and the software write protection control method for the nonvolatile memory, for example, the last address of the flash memory that can be collectively electrically erased and written can be write-protected and stored. It is set in the attribute area as a register, and the address of the area where write protection is to be performed is written to this write protection storage register.

  In this case, the write protect area corresponds to 512 bytes (4096 bits) of a data unit such as a 1-sector unit or a 2-sector unit from the first sector, the last sector, or an arbitrary sector of the Flash memory according to the functional specification of the Flash memory. ) Can be set by the area variable protection method in the first block, the last block, or a block from an arbitrary block to an arbitrary block in units of a sector which represents a group of data of a number of sectors defined by the above or a plurality of sectors. .

  In addition, the write data written to the write protection storage register is transferred to the card controller by hardware reset by input from the system, software reset by register write from the system, or power-on reset by power-on. Transfer to the write protect register in the controller.

  Thereafter, the card controller determines whether or not the address accessed by the user is within the write protection area. As a result, if the address is within the write protection area, write protection is enabled. By disabling write protection, software write protection control can be performed in units of erase.

  As a result, the write protect information is non-volatile, and write protection can be performed in an arbitrary area, and a memory card using a rewritable non-volatile memory such as a Flash memory without a software write protect function, an information processing device, and the like. In this system, the maintainability of the write protect information and the data in the write protect area can be improved.

  In addition, since write protection can be performed in an arbitrary area, the work area of the area where writing is prohibited by software write protection of the memory and the work area of the area where writing is not prohibited other than this area are matched to the system. Can be set, and the effective use of the nonvolatile memory can be enabled.

  The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.

  (1) By setting a write protection storage register for writing an address of an arbitrary write protection area in a predetermined erasing unit in the nonvolatile memory, it is determined whether or not the address accessed by the user is in the write protection area. Since write protection can be performed when the area is within the write protection area, while write protection can be disabled when the area is outside the write protection area, software write protection control can be performed in erase units.

  (2) In the above (1), the setting of the write protection area can be changed from the beginning of the nonvolatile memory to any, from the end to any, or from any to any erasing unit, and the setting of the erasing unit can be changed. By making it possible to change in units of sectors or blocks of devices, good software write protection control corresponding to the functional specifications of the nonvolatile memory becomes possible.

  (3) In the above (1), by applying the present invention to a flash memory, batch electrical erasing and writing can be performed.

  (4) According to the above (1) to (3), the write protect information is made non-volatile, and write protection in an arbitrary area becomes possible. Therefore, a rewritable non-volatile memory having no software write protect function is used. In a system such as a memory card and an information processing device, it is possible to improve the maintainability of write protect information and data in a write protect area.

  (5) According to the above (1) to (3), write protection can be performed in an arbitrary area, and the protection area and work area of the nonvolatile memory can be set according to the system. It can be used.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a memory card using a nonvolatile memory according to an embodiment of the present invention. FIG. 2 is a flowchart of software write protection setting in the embodiment. FIG. 3 is a time chart of transfer of write protection information. 4, FIG. 4 is a block diagram for explaining write protect information transfer, FIG. 5 is an explanatory diagram showing an address map of a memory card, FIG. 6 is a flowchart of write protect control, FIG. 7 is a configuration diagram showing a write protect judging circuit, and FIG. FIG. 9 is a time chart of the write protect control, FIG. 9 is a block diagram illustrating the write protect control, and FIG. 10 is a system configuration diagram using the memory card of the present embodiment.

  First, the configuration of a memory card using the nonvolatile memory according to the present embodiment will be described with reference to FIG.

  The memory card according to the present embodiment is, for example, a flash memory card 1 using a rewritable non-volatile memory without a non-volatile software write protection function, and a flash memory (non-volatile memory) capable of collectively electrically erasing and writing. 2, a reset IC 3 for generating a power-on reset signal when the power is turned on, and a card controller 4 for controlling between these devices and controlling between the memory card interface.

  In the present embodiment, the flash memory 2 mounted on the flash memory card 1 includes, for example, the last chip of a common flash area meaning the memory space of the flash memory 2 and the last sector which is a data unit (512 bytes). A write protection storage register (WP storage Reg) 5 for writing an address of an area where write protection is to be performed is set in an attribute area, and a protection range (protect end sector) can be set from the system.

  The attribute area represents a memory area for storing identification information of the flash memory card 1 and configuration information indicating a hardware configuration and where to allocate the flash memory card 1 in the address space of the system.

  Then, the write protection range by the write protection storage register 5 is set by the variable protection method as an arbitrary sector from the first (0) sector to the (last -1) sector of the common flash area, for example. Is a sector unit (512 bytes). This erasing unit is set according to the functional specifications of the flash memory 2.

  In the card controller 4, a power-on reset performed at the time of power-on, a hardware reset by a reset signal from the system using the Flash memory card 1, and the system writes in a soft reset register set in the card controller 4. As a result, the write protection register (WPReg) 6 for storing the write data transferred from the write protection storage register 5 of the flash memory 2 is set.

  Next, the operation of the present embodiment will be described first with reference to FIG. 2 based on FIG. 2 and with reference to FIG. The control of the write protection setting, and the control of the transfer of the write protection information and the write protection control, which will be described later, are performed by a logic circuit including logic elements constituting the card controller 4.

  First, the last chip and last sector of the flash memory 2 mounted on the flash memory card 1 are set as the write protection storage register 5. The register 5 belongs to the attribute area, and a write protect end address is written in the register 5 to set a write protect range (step 201).

  Since the write protection storage register 5 of the last chip and the last sector of the flash memory 2 is in the flash memory 2, this information is rewritten or held as non-volatile information except that the flash memory 2 is destroyed. be able to.

  Further, in order to transfer the information written in the write protection storage register 5, a power-on reset at power-on, a hardware reset by an input from the system, or a software reset by a register write from the system is performed (step). 202-204).

  As a result, the written information is transferred to the write protect register 6 set in the card controller 4, and the software write protect setting can be completed (steps 205 and 206).

  After the write protect information is transferred to the write protect register 6, the address accessed from the system side is compared with the write protect end address written in the write protect register 6, and the write protect control is performed according to the comparison result. It can be performed.

  Next, transfer of the write protection information will be described with reference to FIG. 4 based on the time chart of FIG.

  First, as shown in FIG. 4, in addition to the write protect register 6, the card controller 4 has a write protect information transfer function that uses a reset pulse generated by a power-on reset, a hardware reset, or a software reset. A reset unit 7 for generating a signal; an address control unit 8 for generating an address when writing to and reading from the flash memory 2; a flash memory control signal generating unit 9 for generating a chip enable signal and an output enable signal; 4 are provided with a software reset register 10 for initializing a register to be set in the memory 4 and generating a reset pulse by software reset, and a register control unit 11 for controlling the register.

  After writing the write protection end address to the write protection storage register 5 in the flash memory 2, for example, at the time of hardware reset, the card controller 4 uses the reset pulse input to the reset unit 7 from the system side. Generates the following transfer signal.

  That is, in the card controller 4, the address control unit 8 generates an address signal (Adr) of the write protection storage register 5 based on a signal from the reset unit 7. Further, the flash memory control signal generator 9 generates a chip enable signal (/ CE) and an output enable signal (/ OE) (low level) based on the signal from the reset unit 7.

  A latch signal for latching the read write protection information in the write protection register 6 in the card controller 4 is generated by the generated address signal, chip enable signal, and output enable signal of the write protection storage register. generate.

  Thus, at the time of hardware reset, the write protection information read from the write protection storage register 5 of the flash memory 2 can be transferred to the write protection register 6 in the card controller 4 and latched.

  At the time of software reset, a write signal generated from the register control unit 11 in the card controller 4 is input to the software reset register 10 using an address control signal in register write from the system side, and "1" is written. Then, "0" is written to generate a software reset pulse.

  Then, the software reset pulse is input to the reset unit 7, and a transfer signal is generated in the card controller 4 in the same manner as at the time of the hardware reset, and the write protection register 6 writes the write protection signal to the write protection register 6. Information can be transferred.

  Further, at the time of power-on reset, when the power of the flash memory card 1 is turned on, a power-on reset pulse is generated by the reset IC 3 and is input to the reset unit 7. Similarly, a transfer signal can be generated to enable transfer of the write protection information from the write protection storage register 5 to the write protection register 6.

  Next, the write protection control will be described based on the flow of FIG. 6 with reference to FIGS. 5 and 7 to 9.

  First, the flash memory card 1 has an address mapping as shown in FIG. 5, and the write protection storage register 5 is set in the last chip and the last sector of the common flash area. , And therefore cannot be accessed as a common flash area.

  As shown in FIG. 9, the card controller 4 has a write protect area determining unit 12 for determining whether or not the address at which the system has accessed the flash memory card 1 is within the write protect area, as shown in FIG. A data control unit 13 for controlling data to be written to the flash memory 2 is provided. The write protection area determination unit 12 compares a sector address with a protect end sector address, and performs write protection control on the data control unit 13. The protection signal is transmitted.

  That is, as shown in FIG. 7, the write protect area determining unit 12 stores a sector address, a write protect upper register (WPUReg) for storing the upper 8 bits of the sector address, and a write protect low register (WPLReg) for storing the lower 8 bits. A size discriminating circuit 14 for comparing the address with the protect end sector address stored in the write protect register 6) is provided, and a protect signal is generated.

  Then, first, after setting the software write protection, when a write access (/ CE, / WE) to the flash memory card 1 is issued from the system side to the common flash area, the write protection area determination unit in the card controller 4 At 12, the protect end address of the write protect register 6 is compared with the sector address accessed from the system side (steps 601 and 602).

  As a result, if, for example, (sector address at the time of writing of the flash memory 2) ≦ (protect end sector address of the write protect register 6), it is determined that the data is within the write protect range, and the write protect signal is sent from the write protect area determination unit 12 to the write protect signal. The flash memory 2 is generated and input to the data control unit 13. The data control unit 13 converts the write data to the flash memory 2 into a reset command or an invalid command and writes the data into the flash memory 2 (steps 603 and 604).

  The reset command is a command for resetting the write setup state, and the invalid command represents a command other than a preset command, and these commands are used at the time of write protection.

  On the other hand, if (sector address at the time of writing of the flash memory 2)> (protect end sector address of the write protect register 6), it is determined that the write protection is out of the write protection range, and the write data is written to the flash memory 2 as normal write as it is. (Steps 603 and 605).

  As a result, it is determined whether or not the address accessed at the time of writing is within the write protection range.If the address is within the write protection range, the write protection is enabled.If the address is outside the write protection range, the write protection is disabled. Normal light can be enabled.

  The Flash memory card 1 configured as described above is applied to, for example, a system such as an information processing apparatus as shown in FIG. 10 and is used in addition to the Flash memory card 1 having the Flash memory 2 and the Flash memory card 1. It comprises a CPU 16, a RAM 17, a ROM 18, a printer 19, a hard disk 20, a floppy (R) disk 21 and the like connected via a card interface 15.

  In this system, the RAM 17, the ROM 18, and the Flash memory card 1 belong to a memory area, and the printer 19, the hard disk 20, and the floppy (R) disk 21 belong to an I / O area. By determining whether the address is within the write protection range, software write protection control as a system can be performed.

  Therefore, according to the flash memory card 1 of the present embodiment, the write protection storage register 5 is set in the flash memory 2 and the end sector address of the write protection range is stored in the write protection storage register 5, thereby enabling the user to store the data. Determines whether the address accessed from the side is within the write-protected range.If the address is within the write-protected range, write-protect is enabled.If the address is out of the write-protected range, write-protect is disabled. Write protection control can be performed in any area.

  In particular, the present invention can be favorably applied to a flash memory card 1 using a flash memory 2 without a software write protect function and a system such as an information processing device, and maintainability of write protect information and data in a write protect area can be improved. Further, the write protection range can be set to an arbitrary area, and the protection area of the write prohibition area and the work area of the other area can be set according to the system in order to use the flash memory 2 effectively.

(Embodiment 2)
FIG. 11 is a configuration diagram showing a memory card using a nonvolatile memory according to another embodiment of the present invention.

  The memory card of the present embodiment is a Flash memory card 1a using a rewritable Flash memory (non-volatile memory) 2a having no nonvolatile software write protection function as in the first embodiment. The difference from this is that the write protection range of the flash memory 2a is defined from the (last -1) sector.

  That is, the write protection range (protect start sector) set in the write protection storage register 5a of the flash memory 2a can be set from the (last -1) sector of the common flash area to an arbitrary sector.

  Therefore, also in the present embodiment, under the control of the card controller 4a in which the write protect register (WPReg) 6a is set, the nonvolatile software write protection of the flash memory card 1a using the flash memory 2a without the software write protect function is performed. Control can be enabled in any area from the (last-1) sector.

(Embodiment 3)
FIG. 12 is a configuration diagram showing a memory card using a nonvolatile memory according to still another embodiment of the present invention.

  The memory card according to the present embodiment is a Flash memory card 1b using a rewritable Flash memory (non-volatile memory) 2b having no nonvolatile software write protection function as in the first and second embodiments. The difference from the first and second embodiments is that the write protection range of the flash memory 2b is defined by a variable method using a start address and an end address.

  That is, the write protection range (protect start and end sectors) set in the write protection storage register 5b of the flash memory 2b can be set from any sector to any sector in the common flash area.

  Therefore, also in the present embodiment, the flash memory 2b without the software write protection function is controlled by the card controller 4b in which the write protection register 6b of the write protection start register (WPSReg) and the write protection end register (WPEReg) are set. Non-volatile software write protection control of the used Flash memory card 1b can be performed in any area from any area.

(Embodiment 4)
FIG. 13 is a configuration diagram showing a memory card using a nonvolatile memory according to still another embodiment of the present invention.

  The memory card according to the present embodiment is a Flash memory card 1c using a rewritable Flash memory (non-volatile memory) 2c having no nonvolatile software write protection function as in the first to third embodiments. The difference from the first to third embodiments is that the write protect unit of the flash memory 2c is a two-sector unit.

  That is, the write protection range (protect end sector) of the write protection storage register 5c set in the (final-1) and last sector of the flash memory 2c can be set in units of two sectors in the common flash area.

  Therefore, also in the present embodiment, under the control of the card controller 4c in which the write protect register (WPReg) 6c is set, the nonvolatile software write protection of the Flash memory card 1c using the Flash memory 2c without the software write protection function is performed. Control can be performed in an area of two sectors.

(Embodiment 5)
FIG. 14 is a configuration diagram showing a memory card using a nonvolatile memory according to still another embodiment of the present invention.

  The memory card according to the present embodiment is a Flash memory card 1d using a rewritable Flash memory (non-volatile memory) 2d having no nonvolatile software write protection function as in the first to fourth embodiments. The difference from the first to fourth embodiments is that the write protect unit of the flash memory 2d is not limited to the sector unit, and the device erase unit is a block unit representing a group of a plurality of data such as several sectors.

  That is, the write protection range (protect end block) of the write protection storage register 5d set in the last block of the flash memory 2d can be set in the common flash area in units of device blocks.

  Therefore, also in the present embodiment, under the control of the card controller 4d in which the write protect register (WPReg) 6d is set, the nonvolatile software write protection of the Flash memory card 1d using the Flash memory 2d without the software write protection function is performed. Control can be enabled in a block-by-block area of the device.

(Embodiment 6)
FIG. 15 is a flowchart of write protection control in a memory card using a nonvolatile memory according to still another embodiment of the present invention, and FIG. 16 is a time chart of the write protection control.

  The memory card according to the present embodiment has the same configuration as that of the first embodiment (2 to 5), and uses a rewritable flash memory (non-volatile memory) 2 without a non-volatile software write-protect function. The card 1 is different from the first to fifth embodiments in that write protection is controlled not by write data but by a control signal to the flash memory 2.

  That is, in the present embodiment, first, after software write protection is set, when a write access to the common flash area is issued to the flash memory card 1 from the system side, the protection end address of the write protection register 6 and the system The address is compared with the sector address accessed from the side (steps 1501 and 1502).

  As a result, if, for example, (sector address at the time of writing of the flash memory 2) ≦ (protect end sector address of the write protect register 6), it is determined that the data is within the write protect range, and the write enable signal (/ WE) for writing or Write protection is performed while the control signal of the chip enable signal (/ CE) is negated (high level) (steps 1503 and 1504).

  On the other hand, if (sector address at the time of writing of the flash memory 2)> (protect end sector address of the write protect register 6), it is determined that the write protection is out of the write protection range, and the write data is written to the flash memory 2 as normal write as it is. (Steps 1503 and 1505).

  Therefore, also in the present embodiment, it is determined whether or not the address accessed from the user side is within the write protection range. If the address is within the write protection range, the write control signal is negated to enable the write protection. On the other hand, if it is out of the write protection range, the write protection cannot be performed, and the nonvolatile software write protection control can be performed in an arbitrary area.

(Embodiment 7)
FIG. 17 is a configuration diagram showing a semiconductor memory using a nonvolatile memory according to still another embodiment of the present invention.

  This embodiment is different from the first to sixth embodiments in that the nonvolatile memory 22 itself has a write protect register 23, and furthermore, a write protect area determining unit 24 which determines whether or not the address accessed by the system is in the write protect area. , And a semiconductor memory 26 provided with a write control unit 25 for controlling a write signal and write data to the nonvolatile memory 22. Write data or a write signal is written using a protect signal from a write protect area determination unit 24. Thus, the write protection of the nonvolatile memory 22 can be controlled.

  That is, in the present embodiment, for example, the semiconductor memory 26 such as a flash memory realizes a write protect function as a single unit. As a result of the write protect area determining unit 24, if the write protect area is within the write protect area, the write protect area determining unit 24 A write protect signal is generated and input to the write control unit 25, and the write signal (/ CE, / WE) to the nonvolatile memory 22 is set to a high level, or the write data is set to a reset command or an invalid command. .

  Therefore, in the present embodiment, the protection address set in the write protection register 23 of the nonvolatile memory 22 is compared with the address of access to the nonvolatile memory 22, and if the address is within the write protection range, the write protection is enabled. On the other hand, when the write protection is out of the write protection range, the write protection cannot be performed, and the nonvolatile software write protection control can be performed when the nonvolatile memory 22 itself has the write protection register 23.

  As described above, the invention made by the inventor has been specifically described based on the first to seventh embodiments. However, the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist thereof. Needless to say,

  For example, with regard to the flash memory in the above embodiment, the case where the write protection storage register is set in the last chip and the last sector of the common flash area has been described, but the present invention is not limited to the above embodiment. Alternatively, the present invention can be applied to a case where the information is set in the first chip and the first sector of the common flash area.

  Further, it goes without saying that the write protection range and the erasing unit are appropriately set in accordance with the function specifications of the flash memory along with the setting of the write protection storage register.

  The nonvolatile memory according to the present embodiment can be applied not only to a flash memory but also to other nonvolatile memories such as an EEPROM capable of electrically erasing and writing data on a bit-by-bit basis. For example, the present invention is widely applicable to information processing apparatuses and memory cards in general, as well as nonvolatile memory devices.

1 is a configuration diagram illustrating a memory card using a nonvolatile memory according to a first embodiment of the present invention. 5 is a flowchart of software write protection setting according to the first embodiment. 6 is a time chart of write protection information transfer in the first embodiment. FIG. 4 is a block diagram illustrating write protect information transfer according to the first embodiment. FIG. 4 is an explanatory diagram showing an address map of the memory card according to the first embodiment. 5 is a flowchart of write protection control according to the first embodiment. FIG. 2 is a configuration diagram illustrating a write protection determination circuit according to the first embodiment. 6 is a time chart of write protection control in the first embodiment. FIG. 3 is a block diagram illustrating write protection control according to the first embodiment. FIG. 2 is a system configuration diagram using a memory card according to the first embodiment. FIG. 9 is a configuration diagram illustrating a memory card using a nonvolatile memory according to a second embodiment of the present invention. FIG. 9 is a configuration diagram illustrating a memory card using a nonvolatile memory according to a third embodiment of the present invention. FIG. 9 is a configuration diagram illustrating a memory card using a nonvolatile memory according to a fourth embodiment of the present invention. FIG. 14 is a configuration diagram illustrating a memory card using a nonvolatile memory according to a fifth embodiment of the present invention. 15 is a flowchart of write protection control in a memory card using a nonvolatile memory according to Embodiment 6 of the present invention. 33 is a time chart of the write protect control in the sixth embodiment. FIG. 19 is a configuration diagram illustrating a semiconductor memory using a nonvolatile memory according to a seventh embodiment of the present invention.

Explanation of reference numerals

1,1a-1d Flash memory card 2,2a-2d Flash memory (non-volatile memory)
3 Reset IC
4, 4a to 4d Card controller 5, 5a to 5d Write protect save register 6, 6a to 6d Write protect register 7 Reset unit 8 Address control unit 9 Flash memory control signal generation unit 10 Software reset register 11 Register control unit 12 Write protect area Judgment unit 13 Data control unit 14 Size discrimination circuit 15 Card interface 16 CPU
17 RAM
18 ROM
19 Printer 20 Hard Disk 21 Floppy (R) Disk 22 Nonvolatile Memory 23 Write Protect Register 24 Write Protect Area Judgment Unit 25 Write Control Unit 26 Semiconductor Memory

Claims (7)

  A rewritable nonvolatile memory having no nonvolatile software write protection function, wherein a predetermined erasing unit is provided in the nonvolatile memory to perform nonvolatile software write protection control on an address accessed from a user side. A write protection storage register for writing an address of an arbitrary write protection area in the nonvolatile memory.   2. The nonvolatile memory according to claim 1, wherein the write protect area is set so as to be changeable from the beginning to the end of the nonvolatile memory, from the end to the end, or from an arbitrary to an arbitrary erase unit.   3. The nonvolatile memory according to claim 1, wherein the erasing unit is set so as to be changeable in a sector unit or a device block unit.   4. The nonvolatile memory according to claim 1, wherein the nonvolatile memory is a Flash memory.   5. A memory card using the non-volatile memory according to claim 1, 2, 3 or 4, comprising: the non-volatile memory; and a card controller that controls at least between the non-volatile memory and a memory card interface. A memory card characterized by being performed.   5. An information processing apparatus using the nonvolatile memory according to claim 1, 2, 3, or 4, wherein the information comprises the nonvolatile memory, and at least a central processing unit and its peripheral devices. Processing equipment.   A software write protection control method for a rewritable nonvolatile memory having no nonvolatile software write protection function, wherein a write protection storage register is set in the nonvolatile memory, and a protection area is written to the write protection storage register. After performing a reset or power-on reset, this write data is transferred to the write protect register in the card controller, and it is determined whether or not the subsequent address accessed by the user is in the write protect area. The non-volatile memo is characterized in that write protection is enabled when the data is within the area, while write protection is disabled when the area is outside the write protection area, and software write protection is controlled in a predetermined erase unit. Software write protection control method of.

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