JP2606622B2 - Disk device seek method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seek method for a disk drive, and more particularly to a seek method for a disk drive in which rotation of a disk is controlled at a constant linear velocity.

[0002]

2. Description of the Related Art Conventionally, in a disk device such as a CD (Compact Disc) player, a laser beam is applied to a desired track of a disk by controlling the driving of an optical pickup as follows. First, a seek operation of moving the optical pickup by an amount corresponding to the difference between the target track and the track after tracking and tracking is performed. Then, the address is read again at the place where the landing is made, and the track jump or the step jump is further performed according to the difference from the target seek destination address to reach the target track.

When a seek operation is performed, the number of tracks from the current position of the optical pickup to a target seek destination is determined by the following equation, wherein the relative speed between the disk and the optical pickup (hereinafter, linear velocity) is a fixed value. Was calculated.

The track pitch is ρ (constant), the innermost radius of the track on the disk is r ₀ (constant), the linear velocity is v, and two points at radii r ₁ and r ₂ on the disk are A and B. Then, the number of tracks between AB is

[0005]

(Equation 1)

Accordingly, the area of a circle (radius r) that includes an arbitrary point on the disk on the circumference with the center of the disk as the center of the circle is the innermost circumference of the disk with the center of the disk as the center of the circle. It is equal to the sum of the area of a circle (radius r ₀ ) and the area of a track having a track pitch ρ from the innermost track on the disk when the track is moved for a time t at a linear velocity v, and πr ² = πr ₀ ² + ρvt ( 2) Therefore, the radius r at any point on the disk is: r ² = r ₀ ² + (ρvt) / π (3)

[0007]

(Equation 2)

By the way, the disk is provided with a total of eight channels of SUB codes for recording auxiliary data.
The SUB-Q code includes a control code including a flag indicating the disc type and a flag indicating whether copying is prohibited and address data. As the address data, a song number, an index of one song, information on the number of minutes, seconds, and frame of the song, and information on minutes, seconds, and frame of one disc are recorded. ing.

In the equation (4), the time t is obtained from the address data of the SUB-Q code. Therefore, the radii of the points A and B can be obtained from the equation (4). When the times at the points A and B are t ₁ and t ₂ ,

[0010]

(Equation 3)

Conventionally, in the equation (7), for example, it is assumed that v = 1.3 [m / s] which is the center value of the linear velocity standard (1.2 to 1.4 [m / s]) of a compact disk. The track jump was performed by calculating the number N.

[0012]

However, since the linear velocity of the compact disk is set to a constant value for each disk within the above-mentioned standard, the linear velocity of the driven disk is 1.3 [m / s]. ], The error (overshoot amount) from the target track when a track jump is performed increases. In addition, the overshoot amount increases as the track jump distance increases.

When such an overshoot occurs, a track jump processing routine of the microcomputer is performed to move the optical pickup to the target track by performing a track jump from the overshoot position to the target track several times. There is a problem that it becomes complicated, error processing becomes difficult, and seek time becomes uneven.

In view of the above, it is an object of the present invention to provide a seek method for a disk drive capable of performing a seek operation by measuring the linear velocity of each disk and accurately obtaining the number of tracks up to a seek target track. And

[0015]

SUMMARY OF THE INVENTION The above-mentioned problem can be solved by the structure shown in FIG.

That is, a first step of reading out and storing address information recorded at a first predetermined position on a disk, and a second step in a direction opposite to a normal reproduction direction by a predetermined distance from the first predetermined position. A second step of moving the pickup to a predetermined position; and a second step of moving the pickup from the second predetermined position in a normal reproduction direction at a predetermined linear velocity and measuring a moving time for the pickup to move to the first predetermined position. Step 3, a fourth step of obtaining a predetermined linear velocity of the pickup by referring to the moving time and the address information recorded at the first predetermined position, and first address information of the disk at the current position of the pickup Calculating the number of tracks from the pickup to the desired seek destination based on the predetermined linear velocity of the pickup and the second address information of the desired seek destination of the pickup. Pickup by moving controls the pickup is provided a fifth step of moving to a desired seek destination according to.

[0017]

According to the present invention having the above-described structure, the linear velocity of the pickup according to the actual rotation speed of each disk is obtained by the first to fourth steps. And in the fifth step,
The number of tracks to the desired seek destination is calculated from the linear velocity, the first address information of the disk at the current position of the pickup and the second address information of the desired seek destination of the pickup, and pickup is performed based on the number of tracks. Is operated to control the movement to the desired seek destination.

[0018]

2 and 3 are flowcharts of the main part of an embodiment of the present invention. 2 and 3 are continuous flowcharts at points a and b in both figures. In the present embodiment, the seek method shown in the flowchart of FIG. 5 is performed after the processing shown in both figures.

In FIG. 2, first, it is determined whether 15 seconds have elapsed after setting the 15-second timer (step 11) (step 12). If 15 seconds have not elapsed, the TOC (Table Of Content; Information (time code recorded in the lead-in area, indicating the start time and end time of the recorded contents of the program area) is read (step 13). The TOC information can be read usually in 3 to 4 seconds, and if it takes a long time to finish reading, it is considered that there is some abnormality on the disk side.

Then, step 14 is executed, and if the TOC information of the disk has not been read, step 12 is executed.
The process ends when 15 seconds have elapsed. In general, the apparatus is configured to prompt the user to confirm the abnormality of the disk. The timer does not have to be a 15 second timer, but it is desirable that the reading time is sufficiently longer than a necessary reading time and not long enough to irritate the user.

When the TOC information has been read within a predetermined time in the above processing up to step 14, the optical pickup is moved in the normal reproducing direction, that is, from the inner circumferential direction to the outer circumferential direction (from the inner circumferential direction of the disc) in order to quickly escape from the lead-in area. Hereinafter, this direction is referred to as the forward direction, and the outer circumferential direction, which is the reverse direction to the normal reproduction direction, from the outer circumferential direction to the inner circumferential direction. It is determined whether it is in the data area of the disk (step 16). If the optical pickup is not in the data area, steps 15 and 16
Is repeated, and if it is determined in step 16 that the optical pickup has escaped from the lead-in area and is in the data area of the disk, the first step, step 17 and subsequent steps, is executed.

That is, the SUB-Q code of the data area, which is the address information of the disk, is read, and the absolute time (minute, second, frame number) of the disk at the current position (first predetermined position) of the optical pickup is stored ( After step 17), the second step, step 18 ₁ ,..., 1
8 ₄ In a predetermined distance is performed 4 times in succession one track jump in the reverse direction of the optical pickup moves in the opposite direction.

Since the current one-track jump causes an error once every ten times, the probability of erroneous moving distance in the reverse direction by performing this four times consecutively is (1/10) ⁴ = 0.
The measurement accuracy is increased to 01%.

The value of the counter CNT0 is reset (step 19). After step 19, the disk and the optical pickup are controlled so that the linear velocity becomes constant in the forward direction. At this time, the counter CNT0 counts by a constant value at a constant cycle and functions as a timer. , E, D, C, B, A (where F <E <D
<C <B <A).

Subsequently, in FIG. 3, it is determined whether the value of the counter CNT0 has reached the upper limit (step 20). This upper limit is set to the lower limit of the standard of the linear velocity of the compact disc, 1.2 [m, from the reset of the value of the counter CNT0 in step 19 to the return of the optical pickup to the first predetermined position. / s], for example, a value corresponding to a case of 1.15 [m / s] or less.

If the value of the counter CNT0 has not reached the upper limit, it is determined whether the optical pickup has passed the address position (first predetermined position) stored in step 17 (step 21). If the optical pickup has not passed this position, steps 20 and 21 are repeatedly executed,
If the value of the counter CNT0 reaches the upper limit in step 20 before the optical pickup has passed this position, the linear velocity is smaller than a predetermined value (for example, 1.15 [m / s]), so that the linear velocity v = 1. .20 [m / s] is set (step 22).

If it is determined in step 21 that the optical pickup has passed the first predetermined position, the value of the counter CNT0 is read (step 23).
The number of linear velocities is measured from the value of the counter CNT0 at this time by executing steps 24 to 41. The processing of steps 24 to 41 is performed from the point b in FIG.
The process is repeated by returning to step 17 of FIG. 3 and performing four one-track jumps in the reverse direction.

By the way, in the processing after step 24, the values of the counter CNT0 are sequentially changed to constants F, E, D, C, and C corresponding to linear velocities from 1.425 [m / s] to 1.175 [m / s].
B, A (F <E <D <C <B <A) and the linear velocity is set. In the processing after step 24, if the value of the counter CNT0 is small, the linear velocity is high, and if it is large, the linear velocity is low. Here, when the value of the counter CNT0 is F, it corresponds to v = 1.425 [m / s], and when it is E, v = 1.
375 [m / s], in the case of D, v = 1.325 [m / s], C
In the case of B, v = 1.275 [m / s], and in the case of B, v = 1.22
5 [m / s], and the case of A corresponds to v = 1.175 [m / s].

That is, in step 24, the counter
Compare whether the value of CNT0 is CNT0 ≦ A, CNT0 ≦ A
If so, step 25 is executed, and if CNT0> A, step 40 is executed. Step 40 and other Step 2
6, 29, 32, 35, 38 are steps 24, 25,
In the comparison process of the values of the counters CNT0 of 28, 31, 34, and 37, the immediately preceding step (steps 24 and 37 immediately before step 40, step 25 immediately before step 26, step 28 immediately before step 29, respectively). This is processing for checking whether or not the comparison processing of step 31 immediately before step 32, step 34 immediately before step 35, and step 37 immediately before step 38) has been performed three consecutive times. According to these processes, the linear velocity is set only when the same comparison result is repeated three times to increase the measurement accuracy.

FIG. 4 is a flow chart showing the steps 26 (29, 32, 35, 38, and 29) in the main part of the embodiment of the present invention shown in FIG.
It is a detailed flowchart of 40).

That is, in step 25, CNT0 <
B is compared, and if CNT0 <B, step 26
Step 42 is executed. Here, it is determined whether the flag 1 is set. However, since the flag is not set at first, all the flags are cleared (step 4).
3). The flags are set in steps 26, 29, 32, 35, 3
A total of 12 pieces are prepared, each set at 8 and 40, and all of them are cleared at step 43.

Subsequently, the flag 1 is set (step 4).
4) Return to step 17. Next, steps 17 to 25 are executed.
In the case of <B, since the flag 1 is set, the process proceeds to the step 45 as a result of the execution of the step 42. Here, since the previous step 43 has been executed and the flag 2 has not been set, the process returns to the step 17 after setting the flag 12 in the step 46.

Next, from step 17 to step 25
When CNT0 <B in step 25, since flags 1 and 2 are set, steps 42 and 43 are executed in that order, and the process proceeds to step 27. It is determined whether or not CNT0 <B is satisfied three consecutive times by the processing of step 26. In step 26, if CNT0 <B three times in a row,
Since 1.175 ≦ v <1.225, in step 27, the linear velocity v is set to 1.20 [m / s]. In steps 29, 32, 35, 38, and 40, the same processing as in step 26 is performed.

If it is determined in step 25 that CNT0 ≧ B, step 28 is executed. In the same manner as described above, the value of the counter CNT0 is set to CNT0 continuously three times.
It is determined whether <C has been reached. And step 2
If CNT0 <C for 3 consecutive times in 9
Since 5 ≦ v <1.275, the linear velocity v is set to 1.25 [m / s] in step 30.

If it is determined in step 28 that CNT0 ≧ C, step 31 is executed. In the same manner as described above, the value of the counter CNT0 is continuously changed three times.
It is determined whether <D has been reached. And step 3
2. If CNT0 <D for 3 times in a row, 1.27
Since 5 ≦ v <1.325, the linear velocity v is set to 1.30 [m / s] in step 33.

Then, in step 31, CNT0 ≧ D
If the value of the counter CNT0 is reached, step 34 is executed.
It is determined whether 0 <E. Then, in step 35, when CNT0 <E three times in succession, 1.3
Since 25 ≦ v <1.375, the linear velocity v is set to 1.35 [m / s] in step 36.

Further, in step 34, CNT0 ≧ E
If the value of CNT0 is reached, step 37 is executed. In the same manner as above, the value of the counter CNT0 becomes three consecutive times.
It is determined whether 0 <F. Then, if CNT0 <F for three consecutive times in step 38, 1.3
Since 75 ≦ v <1.425, the linear velocity v is set to 1.40 [m / s] in step 39.

Further, in step 37, CNT0
If ≧ F, step 40 is subsequently executed,
In the same manner as above, the value of the counter CNT0 becomes three consecutive times.
It is determined whether CNT0 <F or CNT0 ≧ A. And three consecutive CNT0 <F or
If any of CNT0 ≧ A, v <1.425
<V or 1.175 ≧ v, which means that correct measurement could not be performed, but in step 41, the linear velocity v is set to 1.20 [m / s].

As described above, when the optical pickup is in the data area, the address information is read from the SUB-Q code at the current position, and then the optical pickup is moved in the reverse direction by a predetermined distance (four tracks). The linear velocity is obtained from a value indicated by a counter that operates at a constant cycle while the optical pickup moves in the forward direction and reaches the current position.

FIG. 5 is a flowchart showing a seek method of the disk drive. Step 5 of this flowchart
At steps 1 and 56, the number of tracks to a desired seek destination is calculated using the linear velocity obtained by the above method.

In FIG. 5, it is first determined whether or not the optical pickup is in the lead-in area of the disk (step 51). If the optical pickup is in the lead-in area, a track jump is performed in the outer peripheral direction of the disk, that is, in the data area direction. (Step 52). If the optical pickup is in the lead-in area, the processing of steps 51 and 52 is performed until the optical pickup exits the lead-in area. If it is determined in step 52 that the optical pickup has left the lead-in area, step 53 is executed.

That is, the linear velocity v obtained by the above method
And constants π, ρ, r ₀ and S at the current position of the optical pickup.
By substituting the time t ₁ obtained from the UB-Q code and the time t ₂ from the innermost circumference of the disc to the desired seek destination into the above equation (7), the desired value is calculated from the current position of the optical pickup. The number of tracks N up to the seek destination is obtained.

Subsequently, step 54 is executed. If the number of tracks N is N> +800 or N <-800, the feed kick (step 55) is executed, and the process returns to step 53. The feed kick, for example, drives the drive mechanism of the lead screw type with a feed motor to move the entire optical pickup in the radial direction of the disk, and cannot follow the mechanical eccentricity of the disk and cannot perform detailed control. is there.

Therefore, in step 54, -800 ≦
A series of processes of steps 53, 54 and 55 is repeated until N ≦ 800 and the error from the seek destination is within 1.28 [mm] (track pitch ρ = 1.6 [μm]). . If the error from the seek destination is within 1.28 [mm], the position of the optical pickup can be more finely controlled by the track jump in which the optical pickup is driven by the actuator.

Therefore, in step 54, -800 ≦
When N ≦ 800, the number N of tracks from the current position of the optical pickup to the desired seek destination is set, as in step 53.
Is calculated (step 56), a track jump is performed based on the number N of tracks (step 57), and more detailed control of the optical pickup is performed.

In step 58, it is compared whether the current position of the optical pickup after the track jump is located on the inner circumference of one track from the desired seek destination. This process is performed by comparing the time t ₁ from the innermost circumference of the disc to the current position of the optical pickup with the time t ₂ to the desired seek destination.

If the current position of the optical pickup is not on the inner circumference of one track from the desired seek destination, step 56 is executed.
Returns to step 58 until the current position of the optical pickup becomes one track inner circumference from the desired seek destination.
A series of processing of steps 56, 57, 58 is repeatedly performed.

When the current position of the optical pickup is one track inward from the desired seek destination, the seek operation itself is terminated, and the optical pickup is moved forward at a predetermined speed. First, the current position of the optical pickup is compared with the seek destination, and when the optical pickup reaches the target seek destination, the optical pickup reproduces data recorded on the disc and transfers this data. Enter the operation.

According to the above-described seek method of the disk drive, the linear velocity value obtained by rotating each disk, the address information of the disk at the current position of the optical pickup, the address information of the desired seek destination of the optical pickup, and The track jump from the track number to the seek destination is calculated and the seek is performed. As a result, the amount of overshoot when performing a track jump can be made smaller than before regardless of the distance of the track jump, so that the track jump processing routine can be simplified, and there is no need for error processing. In addition, there is an excellent feature that the seek time becomes uniform.

[0050]

As described above, according to the present invention, the linear velocity of the pickup determined by the first to fourth steps according to the actual rotation of the disk and the first address of the disk at the current position of the pickup. Since the movement of the pickup is controlled by calculating the number of tracks to the desired seek destination from the information and the second address information of the desired seek destination of the pickup, an error between the seek operation and the desired seek destination is performed. There is a feature that can reduce.

[Brief description of the drawings]

FIG. 1 is a principle process chart of the present invention.

FIG. 2 is a flowchart of a main part of one embodiment of the present invention.

FIG. 3 is a flowchart of a main part of one embodiment of the present invention.

FIG. 4 is a detailed flowchart of a main part of one embodiment of the present invention.

FIG. 5 is a flowchart illustrating a seek method of the disk device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st process 2 2nd process 3 3rd process 4 4th process 5 5th process 21 ... 46,51, ... 58 step

Claims (1)

(57) [Claims] 1. A first step of reading out and storing address information recorded at a first predetermined position on a disk, and a second step in a direction opposite to a normal reproduction direction by a predetermined distance from the first predetermined position. To move the pickup to a predetermined position
Moving the pickup from the second predetermined position in a normal reproduction direction at a predetermined linear velocity, and
A third step of measuring a moving time required to move to a predetermined position, and obtaining the predetermined linear velocity of the pickup by referring to the moving time and the address information recorded at the first predetermined position. Step 4; The first of the discs at the current position of the pickup
Calculating the number of tracks to the desired seek destination from the address information, the predetermined linear velocity of the pickup, and the second address information of the desired seek destination of the pickup. A step of moving the pickup to the desired seek destination by controlling the movement of the pickup in response thereto.