JPH07282537A - Data recording/reproducing device and parameter setting method - Google Patents

Abstract

PURPOSE:To realize sure read operation by making various kinds of parameters for deciding a read operation characteristic of a read/write circuit revisable even after a product is manufactured and always setting the optimum value. CONSTITUTION:Before the read operation of a read circuit system, a CPU 4 sets initial values of the parameters stored in an EEPROM 7. When a read error occurs at the time of read operation, the CPU 4 revises the parameters to reset them to the read circuit system. The read operation is re-executed by a read retry means based on the reset parameters. When no read error occurs by re-executing the read operation, the CPU 4 stores the revised parameters in the EEPROM 7 as the optimum values.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device, and more particularly to a read / write circuit for reproducing data from a disk or recording data, wherein a parameter for determining a read operation characteristic is externally set. The present invention relates to a data reproducing / recording device having a read / write circuit capable of performing the above.

[0002]

2. Description of the Related Art Conventionally, for example, a hard disk device (HDD), which is a magnetic disk device, reproduces read data from a read signal read from a disk by a head,
Alternatively, it is provided with a read / write circuit for converting recording data to be recorded on the disk into a write signal (write current). The read / write circuit is roughly classified into a data reproducing system of an amplifier circuit, a filter circuit, a read pulse generating circuit, and a data recording system for converting recorded data into a write current.

In the HDD, data is recorded on a disc at a predetermined recording frequency, and the data transfer rate at the time of data reproduction is determined based on this recording frequency. The read / write circuit is required to set various parameters that determine read operation characteristics to optimum values in order to accurately reproduce data recorded at a predetermined recording frequency. For example, a low pass filter (LPF) is used in the filter circuit, but the cutoff frequency and the boost amount (d) are used as parameters.
It is necessary to set B) to the optimum value.

Recently, as the read / write circuit, a read / write IC (integrated circuit) in which the above circuits are integrated is used. Such read / write ICs are HD
Various parameters can be set from the outside by the CPU (control microprocessor) of D. As a specific product, for example, Analog Device
There is a read / write IC (model AD899) manufactured by s company.

Normally, various parameters of a read / write IC are determined at the time of designing an HDD, and a ROM (read only memory) controlled by the CPU
Stored in. Various parameters stored in the ROM are set in the read / write IC. Then, after the HDD is manufactured as a product, various parameters are fixed without being changed.

However, when the magnetic disk device manufactured as a product is driven, various parameters of the read / write IC set at the time of design are not always optimal values due to variations in characteristics of various components during manufacturing. Also, C
DR (constant density recorder)
In the (ding) type HDD, since the data transfer rate is different for each zone, the read operation characteristics are different for each zone and each head.

In the CDR system, the track on the disc is divided into a plurality of zones in the radial direction so that the recording density is relatively constant over the entire recording surface of the disc. In other words, the number of sectors is different for each zone, and the number of sectors is larger in the outer zone,
The number of sectors becomes smaller toward the inner circumference side. Therefore, the data transfer rate differs for each zone.

[0008]

Conventionally, various parameters that determine the read operation characteristics of the read / write IC are determined at the time of designing the HDD and are fixed without being changed after the product is manufactured. However, due to variations in the characteristics of various parts during manufacturing, the read operation characteristics are
Different for each. Further, in the HDD adopting the CDR method, since the data transfer rate is different for each zone, the read operation characteristics are different for each zone and each head. Therefore, if various parameters that determine the read operation characteristics are fixed, the read margin decreases during the actual read operation,
This will cause a read error to occur.

An object of the present invention is to realize a reliable read operation by making it possible to change various parameters that determine the read operation characteristics of the read / write circuit and always set an optimum value even after the product is manufactured. It is to provide a data recording / reproducing device capable of performing the same.

[0010]

The present invention uses, as a read circuit for reproducing read data from a read signal read by a head, a read circuit means path capable of externally setting a parameter for determining a read operation characteristic. HDD
Etc. is a data recording / reproducing device. The present apparatus includes memory means for storing parameters, parameter setting means for setting parameters in the read circuit means, read error determining means for determining a read error when a read operation is executed, and changing and resetting parameters. There is provided a parameter changing means, a read retry means for re-executing the read operation, and a memory control means for storing the changed parameter in the memory means.

[0011]

In the present invention, the initial values of the parameters are stored in the memory means after manufacturing or before shipping. Before the read operation of the read circuit means, the parameter setting means sets the initial value of the parameter stored in the memory means in the read circuit means. The read error determination means determines whether or not a read error has occurred during the read operation executed based on the set parameters. When a read error occurs, the parameter changing means changes the parameter and resets it by the parameter setting means. The read retry unit re-executes the read operation based on the reset parameter. If the read error does not occur due to the re-execution of the read operation, the memory control means stores the changed parameter in the memory means. Therefore, the optimum parameter is stored in the memory means and set in the read circuit means during the read operation.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the main part of the HDD of the embodiment,
2 is a block diagram for explaining the configurations of the read / write circuit and the EEPROM of the same embodiment, FIG. 3 is a flow chart for explaining the operation of the same embodiment, and FIG. 4 is a parameter changing process of the same embodiment. It is a conceptual diagram for doing.

As shown in FIG. 1, the HDD of the embodiment is
It has a read / write circuit 12 for recording data on the disk 2 by the head 1 or reproducing the data read by the head 1 in accordance with a command from the host computer. One or a plurality of disks 2 are provided, and in the same embodiment, there is one disk 2 for convenience. Also,
A plurality of heads 1 are provided corresponding to both sides of one disk 2.

The head 1 is held by a head actuator 15a, as shown in FIG. The head actuator 15 a is rotationally driven by a voice coil motor (VCM) 15 to move the head 1 in the radial direction of the disk 2. The VCM 15 is a VCM under the control of the CPU 4.
A drive current is supplied from the driver 14 to control the drive. The disk 2 is rotationally driven by the spindle motor 3 when the HDD is activated, and rotates at high speed. Control circuit 13
Includes a VCM driver 14 and a driver for the spindle motor 3, and controls the drive of the drive mechanism such as the head 1 and the disk 2.

The read / write circuit 12 is, for example, Ana.
This circuit is composed of a read / write IC (model AD899) manufactured by Log Devices, and is a circuit capable of externally setting various parameters for determining read operation characteristics. The read / write circuit 12 is roughly divided into a write circuit system and a read circuit system that convert the write data (NRZ encoded data) transferred from the host computer into a write signal (write current) current and supply it to the head 1. . In the embodiment, the description of the write circuit system is omitted, and only the read circuit system will be described.

The read circuit system of the read / write circuit 12 is made up of various circuit elements shown in FIG. 2, as will be described later. The read signal (analog signal) read by the head 1 is converted into digital read data (NRZ encoding). Play back the data) and interface controller (HD
C) Output to 8. The read signal read by the head 1 is amplified by the head amplifier 11 and input to the read circuit system.

The HDC 8 constitutes an interface between the HDD and the host computer, and exchanges read / write data and various interface signals (including read / write commands from the host computer) through the interface port 9. Buffer memory 10
Is controlled by the HDC 8 to temporarily store read / write data in a DRAM (dynamic RA).
M).

The CPU 4 is a control microprocessor (microcontroller) for executing various control processes such as servo control. In this embodiment, the CPU 4 executes the read circuit system parameter setting processing of the read / write circuit 12. The CPU 4 operates according to a program stored in the ROM 5. The CPU 4 sets parameters that are externally input through the EEPROM port 6 to the EEPROM.
Save in ROM7. The CPU 4 executes a parameter setting process for setting the parameters read from the EEPROM 7 in the read circuit system of the read / write circuit 12.

EEPROM (electrically)
erasable programmable re
As shown in FIG. 2, the ad only memory) 7 is a non-volatile memory that stores a parameter table including various parameters C, B, S, W (described later) of the read circuit system.

As shown in FIG. 2, the read circuit system of the read / write circuit 12 has an AGC (automatic)
gain control) amplifier 12a, low-pass filter circuit (LPF) 12b, binarization circuit 12c, PL
It has an L (phase-locked loop) 12d, a decoder 12e, and a servo circuit 12f.

The AGC amplifier 12a is the head amplifier 11
This is an amplifier circuit for maintaining the read signal from the device at a predetermined level. The LPF 12b is a filter for removing a predetermined high-band noise, and in the embodiment, a parameter C of a cutoff value (cutoff frequency) and a parameter B of a boost amount (dB) are set by the CPU 4.
The binarization circuit 12c is a circuit for generating a read pulse from the read signal output from the LPF 12b,
In this embodiment, the slice level value parameter S is set to the CPU.
4 is set.

The PLL 12d is a circuit for detecting a data pulse from the read pulse generated by the binarization circuit 12c, and in this embodiment, the window center value parameter W is set by the CPU 4. Decoder 12
e is a circuit for decoding the detected read data into NRZ encoded data. The interface controller 8 stores the read data reproduced by the decoder 12e in the buffer memory 10 and transfers the read data to the host computer through the interface port 9.

The servo circuit 12f samples the servo signal from the read signal from the LPF 12b, and the head 1
To the CPU 4 as the positioning control data. Here, the servo signal is a reproduction signal of burst data for positioning the head 1 at the center of the track among the servo data recorded on the disk 2. The servo data includes a cylinder address (track address) for controlling the movement of the head 1 to a target track, in addition to the burst data.

As shown in FIG. 2, the CPU 4 controls the VCM based on the servo signal output from the servo circuit 12f.
A position control for driving the head 15 to position the head 1 at the center of the target track is executed. At this time, the VCM driver 14 supplies a drive current according to the control amount from the CPU 4 to the VCM 15 to drive the VCM 15.

Next, the operation of the embodiment will be described. In this embodiment, when the HDD is manufactured (before shipment as a product), E
Initial values of parameters C, B, S, and W that determine the read operation characteristics of the read circuit system are input through the EPROM port 6. CPU 4 is an EEPROM port 6
EEP the parameters C, B, S, W, T input from
Save in ROM7.

In the EEPROM 7, as shown in FIG.
The parameters C, B, S, W, T are stored for each predetermined address. Each of the parameters C, B, S and W is a table composed of the zone value of the disk 2 and the parameter value set for each head number of the head 1. In this embodiment, it is assumed that the present invention is applied to a CDR type HDD. In the CDR method, all tracks on the disc 2 are divided into a plurality of zones. The number of sectors of each track included in the same zone is the same, but the number of sectors is different for each zone. That is, the number of sectors in zone 0 on the outer peripheral side is relatively large, and the number of sectors in zone 4 on the inner peripheral side is relatively small. In other words, in the CDR system, the data recording densities of the zones 0 to 4 are the same, but the data transfer rates are different in the zones 0 to 4. Parameters C, B, S, W
Is set for each zone value (number) and head number to which the track to be accessed belongs in the read operation in which the head 1 reads data from the disk 2.

Next, referring to the flow chart of FIG. 3, the parameter setting process for setting the parameters C, B, S and W in the read circuit system of the read / write circuit 12 when the HDD is shipped as a product and driven is described. explain.

First, when a read command is issued from the host computer, it is received by the interface controller 8 through the interface port 9 (step S1). The CPU 4 calculates physical address information to be accessed from the logical address information included in the read command received by the controller 8 (step S).
2). Here, the physical address information includes a zone value on the disk 2, a cylinder number (track number), and a head number (meaning the data surface of the disk) in order to specify the data to be read from the disk 2.

The CPU 4 sets the head 1 having the designated head number to the disk 2 according to the calculated physical address information.
Positioning is performed on the track having the track number belonging to the above designated zone value, and the read operation is executed.

Before executing this read operation, the CPU 4
Initial values of various parameters C, B, S, W are read from the EEPROM 7 and set in the read circuit system of the read / write circuit 12 (steps S3, S4). Specifically, when the zone value 0 and the head number 0 are designated by the calculated physical address information, as shown in FIG.
The cutoff frequency parameter C is read from the address A0 of the PROM 7, and the boost amount parameter B is read from the address D0. The parameters C and B are set in the LPF 12b of the read circuit system. Here, the read / write IC constituting the read circuit system is provided with an input terminal for parameter setting. The CPU 4 converts the read parameter value into an input voltage or an input current by a D / A conversion circuit (not shown) and inputs it to an input terminal to set a specified parameter.

Similarly, the CPU 4 reads the parameter S of the slice level value from the address C0 of the EEPROM 7 and sets it in the binarization circuit 12c. Also, EEPRO
The window center value parameter W is read from the address B0 of M7 and set in the PLL 12d. Furthermore, EE
The parameter T of the track offset value is read from the address E0 of the PROM7. The CPU 4 adjusts the track offset at the time of positioning using the parameter T of the track offset value at the time of controlling the positioning of the head 1.

After such parameter setting processing, the read operation is executed by the head (head number 0) 1 positioned on the track to be accessed (here, included in the zone value 0) (step S5). The read signal output from the head 1 is amplified by the head amplifier 11 and input to the read circuit system shown in FIG. In the read circuit system, as described above, the AGC amplifier 12a, LP
The F12b, the binarization circuit 12c, the PLL 12d, and the decoder 12e reproduce the NRZ encoded data and output it to the interface controller 8. At this time, the LPF 12b, the binarization circuit 12c, and the PLL 12d respectively receive the parameters C and C set by the CPU 4.
It operates with the characteristics of B, S, and W.

Normally, the interface controller 8 stores the read data reproduced by the read circuit system in the buffer memory 10, and the interface port 9
To the host computer. In this embodiment, the interface controller 8 executes a read data check process to determine whether a read error has occurred (step S6). If no read error occurs, the reproduced read data is transferred to the host computer, and the read operation ends. Therefore, with the zone value 0 and the head number 0 according to the access target, various parameters C, B, S, and
Each initial value of W and T is determined to be the optimum value.

On the other hand, if a read error occurs,
The initial values of the various parameters C, B, S, W, and T are determined to be inappropriate, and the CPU 4 shifts to the parameter changing process (YES in step S6, S7). That is, CPU
4 changes each initial value of various parameters C, B, S, W, T based on the parameter changing processing routine stored in the ROM 5, and resets them in the corresponding circuit of the read circuit system (step S8). .

After resetting the changed parameters, the CP
The U4 executes a read retry that is a re-execution of the read operation for the same access target (step S9).
That is, the head (head number 0) 1 reads a read signal from the track to be accessed (included in the zone value 0) and outputs it to the read circuit system. The lead circuit system is A
GC amplifier 12a, LPF 12b, binarization circuit 12c,
The PLL 12d and the decoder 12e reproduce the NRZ encoded data from the read signal and output it to the interface controller 8. At this time, the LPF 12b,
The binarization circuit 12c and the PLL 12d are respectively the CPU 4
It operates with the characteristics by the change parameters C, B, S, W reset by.

The interface controller 8 executes read data check processing by read retry,
It is determined whether a read error has occurred (step S10). If no read error occurs, CP
U4 is the changed various parameters C, B, S, W, T
To the corresponding address (here, A0
To E0) and updates the parameter table (step S11).

On the other hand, if a read error occurs,
The CPU 4 executes the parameter changing process again, and repeats resetting, read retry, and read error check (YES in step S10).

A specific example of the parameter changing process (step S7) will be briefly described with reference to FIG. The retry count in FIG. 4 means the number of read retry operations. The center value means a reference value (initial value) of each parameter (W, T, B, S).

In the process of changing the parameter W of the window center value, as shown in FIG. 4A, 0, ± 2, ± with respect to the center value for each count of the retry count.
An offset of 4 is added. In the process of changing the parameter T of the track offset value, as shown in FIG. 4 (B), offsets of 0, ± 2, and ± 4 are added to the center value every 5 counts of the retry count. In the process of changing the boost amount parameter B, FIG.
As shown in, every 25 counts of retry count,
Offsets of 0, +1, +2 are added to the center value. Furthermore, in the process of changing the parameter S of the slice level value, as shown in FIG. 4D, 0 and +1 offsets are added to the center value every 75 counts of the retry count.

In this way, various parameters C, B, S, W of the read circuit system are stored in the EEPROM 7 as initial values (reference values) when the HDD is manufactured. When the HDD is driven after being shipped as a product, various parameters C, B, S, W read from the EEPROM 7 are set in the read circuit system of the read / write circuit 12.

In response to the read access (command issuance) from the host computer, the read circuit system executes the read operation according to the set various parameters C, B, S and W. At this time, if a read error occurs, it is determined that the set various parameters C, B, S, W are incorrect, and the parameter changing process is executed. After this change processing, the read retry operation is executed, and when the read error does not occur, the changed various parameters C, B, S, W are determined as optimum values, and EEPRO is set.
The parameter table of M7 is updated. EEPROM
Since 7 is a non-volatile memory, it retains the stored various parameters C, B, S, W even when the HDD is powered off. At the time of driving the next HDD, the changed various parameters C, B, S, W are set from the EEPROM 7 to the read circuit system.

Therefore, in the CDR type HDD, the optimum value parameter corresponding to the access target (physical address of zone and head number) can be stored in the EEPROM 7. As a result, at the next read operation of the same access target, it becomes possible to set the optimum value parameter from the EEPROM 7 to the read circuit system.

In this embodiment, the CDR type HDD is used.
Although it was applied to the
It can also be applied to HDDs other than the system. That is, various parameters may be set for each cylinder divided into a head number and a region on the disk 2 which is larger than the zone (for example, an outer peripheral region, an intermediate region, an inner peripheral region).

[0044]

As described above in detail, according to the present invention, various parameters for determining the read operation characteristic of the read / write circuit set at the time of designing the device can be used for the inspection or the HDD read retry operation. Can be changed to the optimum value. Therefore, it is possible to reduce a situation in which a read margin is reduced and a read error occurs during an actual read operation due to factors such as variations in characteristics of various components during manufacturing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of an HDD according to an embodiment of the present invention.

FIG. 2 is a read / write circuit and EEP according to the embodiment.
FIG. 3 is a block diagram for explaining the configuration of a ROM.

FIG. 3 is a flowchart for explaining the operation of the embodiment.

FIG. 4 is a conceptual diagram for explaining a parameter changing process of the embodiment.

[Explanation of symbols]

1 ... Head, 2 ... Disk, 4 ... CPU, 6 ... EEPR
OM port, 7 ... EEPROM, 8 ... Interface controller, 12 ... Read / write circuit, 12b ...
LPF, 12c ... Binarization circuit, 12d ... PLL, 12e
…decoder.

Claims (7)

[Claims] 1. A data recording / reproducing apparatus for recording / reproducing data on / from a disk by a head, wherein a read operation for reproducing read data from a read signal read from the disk by the head is executed to determine the read operation characteristic. Read circuit means capable of externally setting a parameter to be stored, memory means for storing the parameter, parameter setting means for setting the parameter stored in the memory means in the read circuit means, and read circuit means Read error determination means for determining a read error when a read operation is performed, and when the determination result of the read error determination means is a read error, the parameter is changed and the read circuit is set by the parameter setting means. Parameter changing means to reset the means, When the read retry means for re-executing the read operation of the read circuit means based on the parameter reset by the parameter changing means, and the judgment result of the read error judging means accompanying the re-execution of the read operation are normal. And a memory control unit for storing the parameter changed by the parameter changing unit in the memory unit. 2. The read circuit means includes a low-pass filter circuit, a binarization circuit, and a PLL circuit, and the parameter setting means includes cut-off frequency and boost amount parameters of the low-pass filter circuit, and the binarization. 2. The data recording / reproducing apparatus according to claim 1, wherein a slice level parameter of a circuit and a window center parameter of the PLL circuit are set. 3. The memory means comprises a non-volatile memory that retains the memory even after the power is turned off, and the parameter setting means reads out an initial parameter stored in the memory means or a parameter changed by the parameter changing means. The data recording / reproducing apparatus according to claim 1, wherein the data is set in the read circuit means before the read operation. 4. A CDR (constant d) having a disk having a plurality of tracks, the track being divided into a plurality of zones, and recording and reproducing data having a different frequency on the disk by the head.
In a data recording / reproducing apparatus of an energy recording type, a read circuit means for executing a read operation for reproducing read data from a read signal read from the disk by the head and externally setting a parameter for determining the read operation characteristic. A memory means for storing the parameters; a parameter setting means for setting the parameters for each of the zones and heads stored in the memory means in the read circuit means; and a read operation by the read circuit means. And a read error judging means for judging a read error when executing the above, and when the judgment result of the read error judging means is a read error, the parameters corresponding to the zone and head from which the data is read are changed to The lead is read by the parameter setting means. And a read retry to re-execute the read operation of the read circuit means for the same zone and head in which the read error has occurred, based on the parameter changing means for resetting to the path means and the parameter reset by this parameter changing means. And a memory control means for storing the parameter changed by the parameter changing means in the memory means when the result of judgment by the read error judging means due to re-execution of the read operation is normal. A data recording / reproducing apparatus characterized in that 5. The read circuit means includes a low-pass filter circuit, a binarization circuit, and a PLL circuit, and the parameter setting means includes cut-off frequency and boost amount parameters of the low-pass filter circuit, and the binarization. 5. The data recording / reproducing apparatus according to claim 4, wherein a slice level parameter of the circuit and a window center parameter of the PLL circuit are set for each zone. 6. The memory means comprises a non-volatile memory that retains memory even after power-off, and the parameter setting means is changed by the initial parameter for each zone stored in the memory means or the parameter changing means. 5. The data recording / reproducing apparatus according to claim 4, wherein the read parameter is read and set in the read circuit means before the read operation. 7. A data recording / reproducing apparatus having a read circuit means for executing a read operation for reproducing read data from a read signal read from a disk by a head and externally setting a parameter for determining this read operation characteristic. A step of storing the initial value of the parameter in the memory means for storing the parameter, a step of setting the parameter stored in the memory means in the read circuit means, and a step of setting the read circuit means to perform a read operation, A step of determining a read error; a step of changing the parameter and resetting the read circuit means when the result of the read error determination is a read error; and a step of resetting the read parameter based on the reset parameter. A step of re-executing the read operation of the read circuit means; And a step of storing the changed parameter in the memory means when the result of determination by the read error determination means accompanying the re-execution of the read operation is normal.