JPH0760559B2 - Magnetic disk unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention synchronizes when a plurality of magnetic disk devices are connected so that the servo heads pass the index of each magnetic disk device at the same time. The present invention relates to a magnetic disk device controlled to operate.

[Conventional technology]

Conventionally, the spindle motor control system of this type of magnetic disk device counts the output signal of the crystal oscillator, decodes the count value by a decoder that detects the upper and lower limits of the rotation speed, and controls the rotation speed of the spindle motor. . Also, the index pulse and the external controller sync signal are matched by performing phase control by accelerating or decelerating the spindle motor according to the phase relationship between the pulse generated in the center of the sector counter and the sync signal input from the external controller. It turned out (Sho 59-2
(See Japanese Patent No. 18673).

[Problems to be solved by the invention]

In the conventional magnetic disk device spindle motor control method described above, the speed control is performed within the upper and lower limits of the number of revolutions, and then the synchronous control is performed, so the number of revolutions varies depending on the load on the spindle motor. There is a drawback that it is difficult to make the rotational speeds and phases of a plurality of spindle motors coincide with each other for a long time.

[Means for solving problems]

The magnetic disk device of the present invention includes a rotation signal output circuit that is output based on the rotation of a spindle motor, a frequency generation circuit that generates a constant frequency signal, and a signal output from this frequency generation circuit into a signal for one rotation and one rotation. A counter that counts down, a first pulse width conversion circuit and a second pulse width conversion circuit that convert a signal output from this counter into a desired pulse width, an output of the second pulse width conversion circuit, and a magnetic disk. Flip-flop for discriminating timing relationship with device index pulse, and gate circuit group having inputs of output of this flip-flop, output of first pulse width conversion circuit and output of frequency generation circuit for generating constant frequency signal And a counter that counts down the output of this gate circuit group.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a multi-spindle synchronization control circuit of the present invention.

A plurality of magnetic disks 2 attached to the spindle 1 are rotated by a spindle motor 3. The rotation of the spindle motor 3 is controlled by the power amplifier 4 for driving the spindle motor.
The rotation state is detected by the rotation detector 5. The rotation detector 5 outputs a plurality of pulse trains synchronized with the rotation of the spindle motor 3. The spindle motor driving power amplifier 4 is controlled by the spindle motor rotation speed control PLL circuit 6.

A servo pattern (not shown) is written on the servo surface of the magnetic disk 2, the servo head 7 reads the servo pattern, and the read signal is input to the servo circuit 8 and the pattern detection circuit 9 to output an index pulse. To do. The index pulse (# 1 disk index) is input to the multi-spindle synchronization control circuit 10. Similarly, index pulses output from other magnetic disk devices # 2, # 3, ..., #N are also input to the multi-spindle synchronization control circuit 10. In the conventional magnetic disk device, when a plurality of magnetic disk devices # 2, # 3, ..., #N are used, the phases of the magnetic disk devices are not synchronized even if the rotational speeds match. Therefore, the output times of the index pulses do not match.

An output pulse signal (referred to as a master clock pulse) of the crystal oscillator 11 is input to the counter 12 and the multi-spindle synchronization control circuit 10. The counter 12 counts down the output pulse signal of the crystal oscillator 11 (generally speaking, its frequency is higher than the rotation frequency of the spindle motor by 5 digits or more) and outputs a master index pulse which is a pulse once per revolution. This master index becomes the reference time of the index pulse of each magnetic disk device. The master index pulse is input to the pulse width conversion circuit 13 and the pulse width conversion circuit 14, converted into a predetermined pulse width, and input to the multi-pindle synchronization control circuit 10. The multi-spindle synchronization control circuit 10 has a set of a flip-flop (hereinafter referred to as F / F) 15, a gate circuit 16, a gate circuit 17, and a counter 18 for counting down for each magnetic disk device.

Next, referring to FIG. 2, the multi-spindle synchronization control circuit 10
The operation of will be described. Output of pulse width conversion circuit 14 is F / F15
Input to the data terminal of. The disk index pulse from the magnetic disk device is input to the clock terminal of F / F15. The output of F / F15 is input to one terminal of the gate circuit 16. The output of the F / F16 is the output of the pulse width conversion circuit 14,
In other words, if there is no rising edge of the disc index pulse when a certain pulse with one rotation is HIGH,
Becomes GH and opens the gate circuit 16.

The pulse width of the output of the pulse width conversion circuit 13 corresponds to the desired continuous number of master clock pulses.
The output of the pulse width conversion circuit 13 is input to the other terminal of the gate circuit 16. The output of the gate circuit 16 and the master clock pulse are input to the gate circuit 17. The output of the gate circuit 17 is input to the counter 18, counted down, and output. If the output of the pulse width conversion circuit 14 is HIGH and there is no rising edge of the disk index pulse, the output of the gate circuit 17 is a master clock pulse which is inhibited by a desired continuous number. When the master clock pulse train that has been inhibited in the middle is counted down, the output of the counter 18, that is, the phase of the reference clock of the PLL circuit 16 is delayed at the inhibited portion. Therefore, the phase of rotation of the spindle motor 3 is shifted by the delay. That is, the time at which the index pulse of the magnetic disk device is generated changes, and by continuing this operation, the timing of the master index pulse and the timing of the disk index pulse match. Similarly, if this operation is performed for other magnetic disk devices # 2, # 3, ..., #N, the index timings of all the magnetic disk devices match.

〔The invention's effect〕

As described above, the present invention delays the phase of the reference clock pulse by delaying the phase of the reference clock pulse by performing an operation of inhibiting an arbitrary number of clock pulses in a frequency region higher than the reference clock pulse of the spindle motor rotation control PLL circuit.
There is an effect that it is possible to perform a synchronous operation in which the index timings of a plurality of magnetic disk devices are matched.

[Brief description of drawings]

FIG. 1 is a block diagram showing a magnetic disk device of an embodiment of the present invention, FIG. 2 is a block diagram showing a multi-spindle synchronous control circuit of an embodiment of the present invention, and FIG. 3 is an operation of this embodiment. 2 is a timing chart showing 1 ... Spindle, 2 ... Magnetic disk, 3 ... Spindle motor, 4 ... Spindle motor drive power amplifier, 5 ... Rotation detector, 6 ... Spindle motor rotation control PLL circuit, 7 ... Servo head, 8 ... Servo circuit, 9 ... Pattern detection circuit, 10 ... Multi-spindle synchronous control circuit, 11 ... Crystal oscillator, 12 ... Counter, 1
3,14 …… Pulse width conversion circuit, 15 …… Flip-flop, 16,17 …… Gate circuit, 18 …… Counter.

Claims (1)

[Claims] 1. A magnetic disk device comprising a drive spindle motor for driving a magnetic disk and a control circuit for controlling the drive spindle motor, and a rotation signal output circuit for outputting based on rotation of the spindle motor. A frequency generating circuit for generating a pulse signal having a constant frequency, and a counter for counting down the pulse signal output from the frequency generating circuit to a pulse signal having a frequency corresponding to the frequency of the signal generated once per one rotation of the magnetic disk. And first and second pulse width conversion circuits for converting the signals output from the counter into first and second pulse width signals, respectively, and the output of the second pulse width conversion circuit and the magnetic disk The flip-flop that determines the timing relationship with the index pulse and the output of the flip-flop. And a gate circuit group that receives the output of the first pulse width conversion circuit and a pulse signal of a constant frequency generated from the frequency generation circuit, and a counter that counts down the output of the gate circuit group. Magnetic disk drive.