Fujitsu MHT2030AT Manual/User Guide - Page 72

Theory of Device Operation

4-20

C141-E192-02EN

(2) Seek operation

Upon a data read/write request from the host, the MPU confirms the necessity of

access to the disk.

If a read/write instruction is issued, the MPU seeks the desired

track.

The MPU feeds the VCM current via the D/A converter and power amplifier to

move the head.

The MPU calculates the difference (speed error) between the

specified target position and the current position for each sampling timing during

head moving.

The MPU then feeds the VCM drive current by setting the

calculated result into the D/A converter.

The calculation is digitally executed by

the firmware.

When the head arrives at the target cylinder, the track is followed.

(3) Track following operation

Except during head movement to the reference cylinder and seek operation under

the spindle rotates in steady speed, the MPU does track following control.

To

position the head at the center of a track, the DSP drives the VCM by feeding

micro current.

For each sampling time, the VCM drive current is determined by

filtering the position difference between the target position and the position

clarified by the detected position sense data.

The filtering includes servo

compensation.

These are digitally controlled by the firmware.

4.7.5 Spindle motor control

Hall-less three-phase twelve-pole motor is used for the spindle motor, and the 3-

phase full/half-wave analog current control circuit is used as the spindle motor

driver (called SVC hereafter).

The firmware operates on the MPU manufactured

by Fujitsu.

The spindle motor is controlled by sending several signals from the

MPU to the SVC.

There are three modes for the spindle control; start mode,

acceleration mode, and stable rotation mode.

(1) Start mode

When power is supplied, the spindle motor is started in the following sequence:

a)

After the power is turned on, the MPU sends a signal to the SVC to charge

the charge pump capacitor of the SVC.

The charged amount defines the

current that flows in the spindle motor.

b)

When the charge pump capacitor is charged enough, the MPU sets the SVC

to the motor start mode.

Then, a current (approx. 0.3 A) flows into the

spindle motor.

c)

A phase switching signal is generated and the phase of the current flowed in

the motor is changed in the order of (V-phase to U-phase),

(W-phase to U-

phase), (W-phase to V-phase), (U-phase to V-phase), (U-phase to W-phase),

and (V-phase to W-phase) (after that, repeating this order).

d)

During phase switching, the spindle motor starts rotating in low speed, and

generates a counter electromotive force.

The SVC detects this counter

electromotive force and reports to the MPU using a PHASE signal for speed

detection.

Section	Page
Front Cover	1
FOR SAFE OPERATION	2
Revision History	3
Preface	5
Important Alert Items	9
Manual Organization	11
Contents	13
Illustrations	18
Figures	18
Tables	20
CHAPTER 1 Device Overview	21
1.1 Features	22
1.1.1 Functions and performance	22
1.1.2 Adaptability	22
1.1.3 Interface	23
1.2 Device Specifications	24
1.2.1 Specifications summary	24
1.2.2 Model and product number	25
1.3 Power Requirements	26
1.4 Environmental Specifications	28
1.5 Acoustic Noise	29
1.6 Shock and Vibration	29
1.7 Reliability	30
1.8 Error Rate	31
1.9 Media Defects	31
1.10 Load/Unload Function	31
1.11 Advanced Power Management	32
CHAPTER 2 Device Configuration	35
2.1 Device Configuration	36
2.2 System Configuration	37
2.2.1 ATA interface	37
2.2.2 1 drive connection	37
2.2.3 2 drives connection	38
CHAPTER 3 Installation Conditions	39
3.1 Dimensions	40
3.2 Mounting	41
3.3 Cable Connections	47
3.3.1 Device connector	47
3.3.2 Cable connector specifications	48
3.3.3 Device connection	48
3.3.4 Power supply connector (CN1)	49
3.4 Jumper Settings	49
3.4.1 Location of setting jumpers	49
3.4.2 Factory default setting	50
3.4.3 Master drive-slave drive setting	50
3.4.4 CSEL setting	51
3.4.5 Power Up in Standby setting	52
CHAPTER 4 Theory of Device Operation	53
4.1 Outline	54
4.2 Subassemblies	54
4.2.1 Disk	54
4.2.2 Spindle	54
4.2.3 Actuator	54
4.2.4 Air filter	55
4.3 Circuit Configuration	55
4.4 Power-on Sequence	58
4.5 Self-calibration	59
4.5.1 Self-calibration contents	59
4.5.2 Execution timing of self-calibration	60
4.5.3 Command processing during self-calibration	61
4.6 Read/write Circuit	61
4.6.1 Read/write preamplifier (PreAMP)	61
4.6.2 Write circuit	61
4.6.3 Read circuit	63
4.6.4 Digital PLL circuit	64
4.7 Servo Control	65
4.7.1 Servo control circuit	65
4.7.2 Data-surface servo format	68
4.7.3 Servo frame format	70
4.7.4 Actuator motor control	71
4.7.5 Spindle motor control	72
CHAPTER 5 Interface	75
5.1 Physical Interface	76
5.1.1 Interface signals	76
5.1.2 Signal assignment on the connector	77
5.2 Logical Interface	80
5.2.1 I/O registers	81
5.2.2 Command block registers	82
5.2.3 Control block registers	87
5.3 Host Commands	88
5.3.1 Command code and parameters	88
5.3.2 Command descriptions	92
5.3.3 Error posting	182
5.4 Command Protocol	184
5.4.1 PIO Data transferring commands from device to host	184
5.4.2 PIO Data transferring commands from host to device	187
5.4.3 Commands without data transfer	188
5.4.4 Other commands	190
5.4.5 DMA data transfer commands	190
5.5 Ultra DMA Feature Set	192
5.5.1 Overview	192
5.5.2 Phases of operation	193
5.5.3 Ultra DMA data in commands	193
5.5.4 Ultra DMA data out commands	198
5.5.5 Ultra DMA CRC rules	202
5.5.6 Series termination required for Ultra DMA	203
5.6 Timing	204
5.6.1 PIO data transfer	204
5.6.2 Multiword data transfer	205
5.6.3 Ultra DMA data transfer	206
5.6.4 Power-on and reset	219
CHAPTER 6 Operations	221
6.1 Device Response to the Reset	222
6.1.1 Response to power-on	222
6.1.2 Response to hardware reset	223
6.1.3 Response to software reset	225
6.1.4 Response to diagnostic command	226
6.2 Power Save	227
6.2.1 Power save mode	227
6.2.2 Power commands	229
6.3 Defect Processing	229
6.3.1 Spare area	229
6.3.2 Alternating processing for defective sectors	230
6.4 Read-ahead Cache	232
6.4.1 DATA buffer structure	232
6.4.2 Caching operation	233
6.4.3 Using the read segment buffer	235
6.5 Write Cache	239
6.5.1 Cache operation	239
Glossary	243
Acronyms and Abbreviations	247
Index	249
Comment Form	251

Fujitsu MHT2030AT Manual/User Guide - Page 72

Spindle motor control, phase, W-phase to V-phase

Page 72 highlights