JPH10162503A - Data recording and reproducing apparatus having rewritable non-volatile memory, and method for changing setting data in rewritable non-volatile memory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To store various setting information which are inherent to an apparatus, in addition to a control program, into a rewritable non-volatile memory which requires batch erasure for rewriting, and further allow the setting information to be changed without employing the batch erasure. SOLUTION: On an FROM 11, in addition to a control program unit 113, data area groups 110-0 to 110-n and table areas 112-0 to 112-n are provided. The total number of each of them corresponds to the number of setting data which are inherent to an apparatus. For example, when the setting data in the data area group 110-0 is required to be changed, the least significant bit among bits indicating '1' in the table area 112-0 is changed so as to indicate '0', thereby switching an effective data area. Then, a new setting data is written into the single effective data area corresponding to the bit which has been newly changed to '0'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording / reproducing apparatus having a rewritable nonvolatile memory and a method of changing setting data in the rewritable nonvolatile memory.

[0002]

2. Description of the Related Art A magnetic disk drive is one of typical data recording / reproducing apparatuses for recording / reproducing information. The operation of the magnetic disk device is generally controlled by a CPU (microprocessor) executing a control program. This control program is a printed circuit board (PC #) of a magnetic disk device (magnetic disk drive).
A non-volatile memory, such as RO @ (Read O
nly Memory).

In a magnetic disk drive, parameters such as a gain value of an amplifier and a constant of a filter in accordance with characteristics of a head medium or the like inherent to the drive (drive), or
It has various setting information such as an operation mode according to a shipping destination, for example, power-on spin-up, cache EN (enable) / DIS (disable), master / slave, and the like. These setting information have different values depending on the individual drives, and need to be rewritten for changing the setting value. Therefore, a rewritable nonvolatile memory such as EEP
ROM (Electrically Erasable and Programmable Rea)
d Only Memory).

[0004] From the above, in the conventional magnetic disk drive, a CPU (microprocessor), a ROM (for storing control programs), which is a basic configuration of a computer, and a RAΜ (Random Acceses) as a rewritable volatile memory.
s Memory), an EEPROM or the like as a rewritable nonvolatile memory is required.

[0005]

By the way, in recent magnetic disk devices, in order to make it possible to change a control program, a flash ROM which can rewrite the program is used.
It tends to be stored on OM (FROM). Therefore, if the flash ROM can store setting information such as the above-described various parameters specific to the drive and the operation mode (mode information indicating the operation mode), the EEPROM which has been conventionally used for storing the setting information is unnecessary. Cost can be reduced.

However, since the flash ROM requires an erasing operation of the entire contents once to change the contents, it is impossible to locally rewrite only a few bytes.
Therefore, such a flash ROM is not suitable for storing drive-specific setting information, that is, for storing drive-specific setting information that needs to be rewritten in order to change the setting value for each drive and change the setting value. .

The present invention has been made in consideration of the above circumstances, and has as its object to provide not only a control program but also a rewritable nonvolatile memory which requires batch erasing for rewriting.
An object of the present invention is to provide a data recording / reproducing apparatus and a method for changing setting data in a rewritable nonvolatile memory, which can store various setting information unique to the apparatus and can change the setting information without batch erasing.

[0008]

According to the present invention, there is provided a control program area in which a control program for controlling a device is stored, and a setting data unique to each device used for controlling the device. A data area group including a plurality of sets of data areas provided for setting of setting data, and a clear state is provided for each of the above data area groups, which data area in the corresponding data area group is valid. A rewritable nonvolatile memory that requires batch erasure for rewriting, with a table area reserved for setting a table value to indicate at a certain bit position, and the device-specific settings that are enabled by device control When data needs to be changed, the bit in the clear state of the table value of the corresponding table area is increased by one bit in a certain direction. Newly characterized by providing the setting data changing means for writing new configuration data to the data area of the data area group corresponding to the bit position became clear state.

Further, according to the present invention, when it is necessary to read out effective setting data from the data area group (for example, in the case of initialization processing at power-on), a table area corresponding to the data area group is referred to. Further, there is further provided an effective data area selecting means for selecting a data area in a data area group corresponding to a bit position which has been cleared most recently as a read target.

In such a configuration, a control program required for controlling the apparatus and various setting data unique to the apparatus can be stored in the same rewritable nonvolatile memory (for example, flash ROM). As described above, a rewritable nonvolatile memory (for example, flash memory
OM) and a device using both rewritable non-volatile memory (for example, EEPROM) ROM which does not require batch erasing for rewriting provided for setting of various kinds of setting data unique to the device. Cost can be reduced.

[0011] Further, for each type of device-specific setting data,
It is a rewritable nonvolatile memory that requires batch erasing for rewriting because it prepares multiple sets of data areas for setting the corresponding type of setting data and switches between data areas each time the setting data is changed. The setting data can be changed.

In addition, a table area is provided to indicate which data area in the data area group is valid by a bit position in a clear state. When setting data is changed, the table value in the table area is cleared. Is increased by one bit in a certain direction (predetermined direction of the upper bit side or the lower bit side) (if the number of bits in the clear state is increased to the upper bit side, If the least significant bit is cleared and more bits in the clear state are added to the lower bits, the most significant bit among the bits in the set state is cleared), and the newly cleared bit Since new setting data is written to the data area corresponding to the position, any of the data The bit position where the latest setting data is written to the rear, that is, which data area is valid is the bit position where the clear state was most recently cleared (if the number of bits in the clear state is increased to the upper bit side, the clear If you want to increase the number of cleared bits to the position of the most significant bit in the bits in the state and the lower bits,
The position can be easily determined from the position of the least significant bit among the bits in the clear state. Here, the change of the setting contents (table value) of the table area on the rewritable non-volatile memory which requires batch erasing for rewriting does not require batch erasing if the change is in the direction in which the bit is cleared as described above. Can be done.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a magnetic disk drive according to one embodiment of the present invention.

In FIG. 1, 1 is a disk (magnetic disk) which is a medium on which data is recorded, and 2 is a disk for writing data to the disk 1 (data recording) and reading data from the disk 1 (data reproduction). This is the head (magnetic head) used. Here, disk 1
Are provided in layers (three in the figure), and the heads 2 are provided corresponding to the respective data surfaces of the respective disks 1.

A large number of concentric tracks are formed on both surfaces of the disk 1, and each track is used for positioning control and the like (cylinder data indicating a cylinder number and a positional error in the cylinder indicated by the cylinder data indicating a waveform error). A plurality of servo areas on which servo data (including burst data for indicating amplitude) are recorded are arranged at equal intervals.
These servo areas are radially arranged on the disk 1 over the respective tracks from the center. The area between the servo areas is a user area. A plurality of data sectors are set in the user area between the servo areas.

The disk 1 is a spindle motor (SPM)
3. High speed rotation. The head 2 is attached to a head moving mechanism called a carriage 4, and moves in the radial direction of the disk 1 by the movement of the carriage 4. The carriage 4 is driven by a voice coil motor (VCM) 5.

The spindle motor 3 and the voice coil motor 5 are connected to a motor driver 6. The motor driver 6 drives the motor 3 by supplying a control current to the spindle motor 3 and drives the motor 5 by supplying a control current to the voice coil motor 5. The value of the control current (control amount) is determined by calculation processing of the CPU (microprocessor) 10, and is given, for example, as a digital value.

Each head 2 is connected to a head IC 7 mounted on a flexible printed circuit (FPC). The head IC 7 controls switching of the head 2 and inputs and outputs read / write signals to and from the head 2, and has a head amplifier (preamble) 71 for amplifying an analog output read by the head 2.

The read / write IC 8 receives an analog output (read signal of the head 2) read from the disk 1 by the head 2 and amplified by the head amplifier 71 in the head IC 7, and receives a signal necessary for a data reproducing operation. It has a decoding function for performing processing. This decoding function is realized by, for example, a read circuit (read channel) (not shown) of a PRML (Partial Response Maximum Likelihood) system. The read circuit (read channel) is an AGC amplifier (automatic gain control amplifier) for maintaining the level of the read signal output from the head amplifier 71 in the head IC 7 at a constant level. A filter for removing noise, a binarization circuit for binarizing the output of the filter, and a waveform equalization process for performing an equalization process on the output of the binarization circuit in accordance with a PR (Partial Response) characteristic PR equalizer, maximum likelihood (ML) for detecting a maximum likelihood data sequence (most likely sequence) from digital data (code data sequence) PR equalized by the PR equalizer based on the Viterbi algorithm A Viterbi decoder that performs estimation decoding, and a data sequence detected by the Viterbi decoder is, for example, NR
A decoder that converts the data into Z data and outputs the data to the HDC 14;
And a well-known circuit such as a PLL circuit (not shown) for generating a read synchronization clock (sampling clock) required for executing digital signal processing of the above-mentioned binarization circuit and Viterbi decoder by a phase locked loop. It has a circuit configuration.

In addition to the decoding function, the read / write IC 8 has an encoding function for performing signal processing necessary for recording data on the disk 1, and a reproducing process (servo data) for servo processing such as head positioning control. (Including a process of extracting burst data from servo data).

The servo processing circuit 9 includes a read / write IC
In step 8, signal processing necessary for servo processing is executed upon receiving the reproduced servo data. That is, the servo processing circuit 9 has a decoding function for extracting and decoding cylinder data (cylinder number) and the like in the servo data, and a timing generation function such as a write gate. The servo processing circuit 9 performs A / D (analog / digital) conversion of the burst data (analog signal) extracted by the read / write IC 8 and performs C / D conversion.
It also has an A / D conversion function for outputting to the PU 10.

The CPU 10 is, for example, a one-chip microprocessor. The CPU 10 executes a control program (F) stored in a flash ROM 11 described later.
Each part in the magnetic disk drive is controlled according to W). That is, the CPU 10 controls the servo data (cylinder data and burst data therein) extracted by the servo processing circuit 9.
In accordance with the above, known control such as positioning control for moving the head 2 to a target position (by controlling the driving of the voice coil motor 5 via the motor driver 6) and transfer control of read / write data by controlling the HDC 14 are performed. Do.

In the initialization process when the power is turned on, the CPU 10 stores various parameters and operation modes (mode information representing the device (drive) that are stored in the flash ROM 11 and are currently valid, which are unique to the device (drive). In addition to performing control to develop setting data such as data on the RAM 12, control is also performed to write setting data such as parameters or operation modes on the flash ROM 11 in response to a FROM data setting command from the host device.

The CPU 10 has a flash ROM (hereinafter referred to as a FROM ROM) as a rewritable nonvolatile memory (rewritable ROM) in which a control program (FW) for controlling each unit in the magnetic disk device is stored.
11), a work area of the CPU 10, a CPU 1
RA as a rewritable volatile memory that provides control parameters used by the C.O.
M12 is connected.

As shown in FIG. 2, the FROM 11 has a control program unit 113 for storing a control program common to magnetic disk devices (drives) of the same type.
Data area groups 110-0 (# 0) to 110-n (#n) and table areas 112-0 (# 0) to 112-n (#n)
Is secured.

Each data area group 110-0 to 110-n is
Each of them is used for setting various parameters unique to the device (drive), an operation mode (mode information indicating), and the like. Various parameters specific to the device (drive) applied in the present embodiment include a gain value of an AGC amplifier in a read circuit of the read / write IC 8, a cutoff filter constant of a filter, a filter boost constant, and a binarization circuit. Data threshold level, track offset value for controlling the positioning of the head 2, defect position information on the disk 1, and the like.

The operation mode unique to the device (drive) includes a motor spin-up (power-on spin-up) at power-on (designating whether or not to rotate the drive motor at power-on of the host device). Operation mode, (in a system in which, for example, two drives are connected to one connector, a method of recognizing the drives and specifying which is to be a master or a slave)
Slave operation mode, operation mode after software reset (to specify how much the drive is initialized when reset by a command from the host device), ON / OFF of cache function using buffer memory 15 OF
F, etc.) (for specifying a cache control method).

For example, the data area group 110-0 of the data area groups 110-0 to 110-n includes a plurality of sets, for example, eight sets of data areas 111-0 (# 0) to 111-7.
(# 7). Each of these data areas 111-0 to 1
11-7 are used for storing setting data specific to the same type of device (drive), but only one area of them is used (the latest setting data specific to the device actually used is stored). Designated as a valid area. In the present embodiment, the data size of each of the data areas 111-0 to 111-7 is 4 bytes. The same applies to the other data area groups 110-1 to 110-n.

The table areas 112-0 to 112-n are provided in one-to-one correspondence with the data area groups 110-0 to 110-n, respectively. Table area 112-i (i = 0 to
n) is used for setting information (table value) indicating which of the data areas in the corresponding data area group 110-i is valid.

Taking the table area 112-0 as an example, the data size of the table area 112-0 is 1 byte, and its bits 0 (least significant bit) to 7 (most significant bit) are the data areas 111-0 to 111-0. This corresponds to 111-7.

The 1-byte table value of the table area 112-0 is represented by FFh in hexadecimal notation in a state where the setting data unique to the device (drive) is not written in any of the data areas 111-0 to 111-7. (The h at the end indicates hexadecimal representation), that is, 111111 in binary representation
11d (d at the end indicates binary representation).

The table value of the table area 112-0 is
Each time the setting data unique to the device (drive) is written to a new data area in the data area group 110-0, the bit 7 is set to "1" (set state) continuously from bit 7.
The CPU 10 sets the least significant bit i of the i bits (i is any of 0 to 7) to “0” (clear state).
Will be changed by Therefore, data area group 110
In the state where the (i + 1) th writing of the device-specific setting data for the data area in −0 is performed, that is, the latest device-specific setting data is written to the data area 111-i, In the state where i is valid, all the (i + 1) -th consecutive bits from bit 0 of the table value in the table area 112-0 are "0" (clear state).

From the above, the data area group 110-0
In order to detect the currently valid data area 111-i, the most significant bit position having the bit value “0” is detected from the table area 112-0 corresponding to the data area group 110-0. Often, the data area corresponding to the detected bit position is the target data area. Similarly, to detect the write destination data area of the latest device-specific setting data from the data area group 110-0, the bit value “1” is read from the table area 112-0 corresponding to the data area group 110-0. , The least significant bit position may be detected, and the data area corresponding to the detected bit position becomes the target data area. To instruct the host device to set the latest device-specific data in the data area on the FROM 11, the FRO
A dedicated command called an M data setting command is used.

The above is a description of the other table areas 112-1 to 112-1.
The same applies to the relationship between 12-n and the data areas in the data area groups 110-1 to 110-n. The storage area (physical area) of the FROM 11 is allocated to a part of the memory area of the CPU 10 (memory address space managed by the CPU 10). For example, the table area 112-0 on the FROM 11 has an address (CPU address) 02
The table area 112 is stored in the 1-byte area of 00C02h.
-1 is assigned to the 1-byte area at the next address 0200C03h. The data area group 110-0 is allocated to a 32-byte area of addresses 0200DD2h to 0200DF1h.
For example, the first data area 111-0 in 0-0 is a 4-byte area of addresses 0200DD2h to 0200DD5h, and the next data area 111-1 is an address 0200DD.
6h to 0200DD9h in a 4-byte area, and the last data area 111-7 has addresses 0200DEEh to 0200DEEh.
0200DF1h is allocated to the 4-byte area.

Referring again to FIG. 1, the CPU 10 includes:
A disk controller (HDC) 14 is connected in addition to the FROM 11 and the RAM 12. The disk controller (HDC) 14 controls communication of commands and data with a host device (not shown), and controls data communication with the read / write IC 8 (disk 1). . The HDC 14 stores read / write data in a cache system, for example, RA
Buffer memory (buffer RAM) 1 composed of M, etc.
5 and the host interface 16 are connected.
The host interface 16 serves as an interface between the HDC 14 and the host device. The HDC 14 communicates commands and data with the host device via the host interface 16.

Next, the operation of the magnetic disk drive having the configuration shown in FIG.
(2) Taking the FROM data setting command receiving process as an example
This will be described with reference to the flowcharts of FIGS. (1) Power-on processing First, it is assumed that the power of the magnetic disk device of FIG. 1 is turned on. At this time, the data area group 11 of the FROM 11
It is assumed that the contents of the area including 0-0 and the table area 112-0 are as shown in FIG.

When the power of the apparatus is turned on, the CPU 10 executes an initialization process according to the initialization routine in the control program stored in the control program unit 113 of the FROM 11 as follows according to the flowchart of FIG.

First, the CPU 10 sets the first table area on the FROM 11 (here, address 0200C02h).
, The bit position of the most significant bit that is "0" (clear state) in the table value (1 byte) is detected (step S1). In the example of FIG. 5A, the table area 11
Since the table value of 2-0 is FEh, that is, 11111110d, bit 0 is detected. The data area in the data area group 110-0 corresponding to the bit position (bit 0) detected from the table area 112-0 (here, the first data area 1 in the data area group 110-0)
11-0) is the only valid data area in the data area 111-0.

Therefore, the CPU 10 determines the bit position detected in step S1, that is, the data area 111-0 corresponding to bit 0, from the data area group 110-0 on the FROM 11 corresponding to the referenced table area 112-0. Select (Step S2). Then, the CPU 10 stores the data stored in the selected data area 111-0 (here, the 4-byte data from the address 0200DD2h).
Is read as the latest (valid) device (drive) -specific setting data, and expanded in the corresponding area of the RAM 12 (step S4). In the example of FIG. 5A, since data 80018032h is set in the data area 111-0, the data 80018032h is developed on the RAM 12 as valid data.

The CPU 10 repeatedly executes the above operation while switching the table area to be referred to (step S4).
When all the valid device (drive) -specific setting data set in -0 to 110-n have been expanded in the RAM 12 so that the setting data can be used, another initialization routine is executed ( Step S5) Then, the process proceeds to an idle routine for waiting for a command from the host device. (2) Processing when receiving FROM data setting command Next, processing when receiving a FROM data setting command will be described.

First, the host device sends the data area group 110-0 of the FROM 11 to the magnetic disk device of FIG.
(A data area inside), a new device (drive)
It is assumed that a command (FROM data setting command) instructing to set unique data 80028132h has been issued. At this time, it is assumed that the contents of the area including the data area group 110-0 and the table area 112-0 of the FROM 11 are as shown in FIG.

The FROM data setting command issued from the host device is transmitted to the host interface 16 and the HDC.
14 to the CPU 10. Upon receiving the FROM data setting command from the host device, the CPU 10 performs a FROM data setting command receiving process according to the FROM data setting routine in the control program stored in the control program unit 113 of the FROM 11 according to the flowchart of FIG. Run as

First, the CPU 10 receives the FR from the host device.
Data area group 11 specified by OM data setting command
The 1-byte table value of the table area 112-0 on the FROM 11 corresponding to 0-0 (designated by the address 0200C02h) is read, and the bit position of the least significant bit which is "1" (that is, the bit position of the table area 112-0) is read out. , "0" (bit position one bit higher than the most significant bit), and changes the read table value so that the bit becomes "0" (clear state). Write back to 112-0 (step S11).

In the example of FIG. 5A, the table area 11
The table value of 2-0 is FEh, that is, 11111110d.
Therefore, bit 1 is detected as the bit position of the least significant bit that is "1", and the table value is changed to FCh, that is, 11111100d.
As is apparent, in this table value change processing, "1"
Is changed to "0", but no bit is changed from "0" to "1".

Now, in order to change the contents of the FROM 11, it is necessary to erase the contents of the FROM 11 once. For this reason, local change on the FROM 11 is generally impossible. However, it is possible to change the data bit only if the direction is cleared (from "1" to "0"). On the other hand, in the above-described table value change processing in the present embodiment, there is a bit for changing “1” to “0”, but no bit for changing “0” to “1”.

As described above, by performing write access for writing back the changed table value FCh (11111100d) to the original table area (here, table area 112-0) on the FROM 11, the relevant table area is read. (Here, table area 112-0) the previous table value FEh (11111110d)
To FCh (11111100) as shown in FIG.
d), that is, the state of the detected bit 1 is changed from the original state “1” (set state) to “0”.
(Clear state) can be realized.

As described above, the table value of the table area 112-0 is changed from FEh (11111110d) to FCh.
(11111100d), that is, by changing the bit 1 of the table value of the table area 112-0 from "1" to "0", the valid data area in the data area group 110-0 is changed. Is switched from the first data area 111-0 to the second data area 111-1.

Therefore, the CPU 10 sets the bit position on the table area 112-0 whose bit value has been changed to "0", that is, the data area group 110-0 corresponding to the bit 1.
Data area 111-1 in the FRO from the host device.
It is selected as the write destination of the setting data specified by the M data setting command (step S12), and the selected data area 111-1, that is, the data area 111-1 next to the data area 111-0 that has been valid up to that point ( Here, new setting data 80028132 specified by the command is stored in the area of 4 bytes from address 0200DD6h.
h is written (step S13). The values of the data areas not yet set are all FFh. FIG. 5 (b)
Is the data area group 110-0 of the FROM 11 at this time.
And the contents of the area including the table area 112-0.

Therefore, in this state, the power is shut off,
Thereafter, when the power is turned on again, the data area group 11
The valid data area in 0-0 is the table area 112
By the table value FCh (11111100d) of -0,
Since the data area 111-1 corresponding to bit 1 is indicated, unlike the above-described power-on,
The data in the data area 111-1 is expanded on the RAM 12 as setting data to be actually used.

In this embodiment, the number of setting changes is limited to the number of data areas forming the corresponding data area group. However, since the setting change such as the operation mode change is not frequently performed, this limitation does not substantially cause a problem. Even if all the table areas in the data area group have been used, if, for example, batch erasing of the FROM 11 is performed to rewrite the control program, all the table areas in the data area group are reset. Can be secured as possible.

In the above-described embodiment, the magnetic disk device has been described. However, the present invention requires a control program and various kinds of setting information unique to the device for controlling the device. Not only magnetic disk devices but also data recording / reproducing devices in general, such as magneto-optical disk devices, as long as they use a rewritable nonvolatile memory that requires batch erasure for rewriting for storing various unique setting information, Further, the present invention is applicable to general information equipment.

[0052]

As described above in detail, according to the present invention, not only the control program but also various kinds of setting information unique to the device are stored in the rewritable nonvolatile memory which requires batch erasing for rewriting. The setting information can be changed without batch erasing. This eliminates the need for a rewritable nonvolatile memory that does not require batch erasing, in addition to the nonvolatile memory in which the control program is stored, and can reduce the cost of the device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of area allocation in a FROM 11 in FIG. 1;

FIG. 3 is an exemplary flowchart for explaining processing at the time of power-on in the embodiment.

FIG. 4 is an exemplary flowchart for explaining processing when a FROM data setting command is received in the embodiment.

FIG. 5 shows a data area group 110 of the FROM 11 in FIG.
-0 and the example of the contents of the area including the table area 112-0,
FIG. 4 is a diagram showing before and after execution of a FROM data setting command.

[Explanation of symbols]

10 CPU (setting data changing means, valid data area selecting means), 11 FROM (flash ROM, rewritable nonvolatile memory), 110-0 to 110-n ... data area group, 111-0 to 111-7 ... Data area, 112-0 to 112-n: table area, 113: control program section (control program area).

Claims (4)

[Claims] 1. A data recording / reproducing apparatus in which an apparatus is controlled in accordance with a control program, wherein a control program area in which the control program is stored and a type of setting data unique to each apparatus used for controlling the apparatus are provided. A data area group comprising a plurality of sets of data areas provided for setting of the corresponding type of the setting data, and any of the data areas in the corresponding data area group provided for each of the data area groups A rewritable nonvolatile memory that requires batch erasing for rewriting, and a table area used for setting a table value for indicating a valid bit position in a clear state is reserved; If it is necessary to change the device-specific setting data that is enabled by control, the corresponding table area is required. Setting data changing means for increasing the number of bits in the clear state of the table value by one bit in a certain direction, and writing new setting data in the data area in the data area group corresponding to the bit position newly cleared; A data recording / reproducing apparatus comprising: 2. A data recording / reproducing apparatus in which an apparatus is controlled in accordance with a control program, wherein a control program area in which the control program is stored and a type of setting data unique to each apparatus used for controlling the apparatus are provided. A data area group comprising a plurality of sets of data areas provided for setting of the corresponding type of the setting data, and any of the data areas in the corresponding data area group provided for each of the data area groups A rewritable nonvolatile memory that requires batch erasing for rewriting, and a table area used for setting a table value for indicating a valid bit position in a clear state is reserved; If it is necessary to change the device-specific setting data that is enabled by control, the corresponding table area is required. Setting data changing means for increasing the number of bits in the clear state of the table value by one bit in a certain direction, and writing new setting data in the data area in the data area group corresponding to the bit position newly cleared; When it is necessary to read out valid setting data from the data area group, refer to the table area corresponding to the data area group and read the data area group corresponding to the bit position that has been cleared most recently. And a valid data area selecting means for selecting the data area in the data area as a read target. 3. A method of changing setting data in a rewritable nonvolatile memory applied to an apparatus in which control of the apparatus is performed according to a control program stored in a rewritable nonvolatile memory that requires batch erasing for rewriting. As the rewritable nonvolatile memory, a control program area in which the control program is stored, provided for each type of device-specific setting data used for controlling the device, and a corresponding type of setting data A data area group including a plurality of sets of data areas provided for setting, and a data area group is provided for each of the data area groups, and it is in a clear state which of the data areas in the corresponding data area group is valid. Rewrite enabled with reserved table area for setting table values to indicate bit positions When it is necessary to change the device-specific setting data that is enabled by the control of the device by using a non-volatile memory, the bit in the clear state of the table value of the corresponding table area is changed by one bit in a certain direction. A method of changing setting data in a rewritable nonvolatile memory, wherein setting data is newly written in the data area in the data area group corresponding to a bit position that has been newly cleared. 4. A method for changing setting data in a rewritable nonvolatile memory applied to a device in which control of the device is performed according to a control program stored in a rewritable nonvolatile memory that requires batch erasing for rewriting. As the rewritable nonvolatile memory, a control program area in which the control program is stored, provided for each type of device-specific setting data used for controlling the device, and a corresponding type of setting data A data area group including a plurality of sets of data areas provided for setting, and a data area group provided for each of the data area groups, and which of the data areas in the corresponding data area group is valid, is set to a clear state. Rewrite with reserved table area for setting table values to indicate at certain bit positions When it is necessary to change the device-specific setting data that is valid under the control of the device using a non-volatile memory, the bit in the clear state of the table value of the corresponding table area is set to 1 in a certain direction. When the number of bits is increased, new setting data is written to the data area in the data area group corresponding to the newly cleared bit position, and valid setting data needs to be read from the data area group, Referring to the table area corresponding to the data area group, the data area in the data area group corresponding to the most recently cleared bit position is selected as a read target. How to change setting data in rewritable nonvolatile memory.