Fujitsu MHN2150AT Manual/User Guide - Page 74

Theory of Device Operation

4-22

C141-E120-02EN

d)

If the head is stopped at the reference cylinder from there.

Track following

control starts.

(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. 0.7 A) flows into the

spindle motor.

c)

The SVC generates a phase switching signal by itself, and changes the phase

of the current flowed in the motor 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).

Section	Page
Front Cover	1
FOR SAFE OPERATION	2
Revision History	3
Preface	5
Important Alert Items	9
Manual Organization	11
Contents	13
Figures	18
Tables	19
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	25
1.4 Environmental Specifications	27
1.5 Acoustic Noise	28
1.6 Shock and Vibration	28
1.7 Reliability	29
1.8 Error Rate	30
1.9 Media Defects	30
1.10Load/Unload Function	30
CHAPTER 2 Device Configuration	33
2.1 Device Configuration	34
2.2 System Configuration	36
2.2.1 ATA interface	36
2.2.2 1 drive connection	36
2.2.3 2 drives connection	36
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
CHAPTER 4 Theory of Device Operation	53
4.1 Outline	54
4.2 Subassemblies	54
4.2.1 Disk	54
4.2.2 Head	54
4.2.3 Spindle	55
4.2.4 Actuator	55
4.2.5 Air filter	55
4.3 Circuit Configuration	56
4.4 Power-on Sequence	59
4.5 Self-calibration	60
4.5.1 Self-calibration contents	60
4.5.2 Execution timing of self-calibration	61
4.5.3 Command processing during self-calibration	62
4.6 Read/write Circuit	62
4.6.1 Read/write preamplifier (HDIC)	62
4.6.2 Write circuit	62
4.6.3 Read circuit	65
4.6.4 Digital PLL circuit	66
4.7 Servo Control	67
4.7.1 Servo control circuit	67
4.7.2 Data-surface servo format	70
4.7.3 Servo frame format	72
4.7.4 Actuator motor control	73
4.7.5 Spindle motor control	74
CHAPTER 5 Interface	77
5.1 Physical Interface	78
5.1.1 Interface signals	78
5.1.2 Signal assignment on the connector	79
5.2 Logical Interface	82
5.2.1 I/O registers	83
5.2.2 Command block registers	84
5.2.3 Control block registers	89
5.3 Host Commands	89
5.3.1 Command code and parameters	90
5.3.2 Command descriptions	92
5.3.3 Error posting	164
5.4 Command Protocol	166
5.4.1 PIO Data transferring commands from device to host	166
5.4.2 PIO Data transferring commands from host to device	168
5.4.3 Commands without data transfer	170
5.4.4 Other commands	172
5.4.5 DMA data transfer commands	172
5.5 Ultra DMA Feature Set	175
5.5.1 Overview	175
5.5.2 Phases of operation	176
5.5.3 Ultra DMA data in commands	176
5.5.4 Ultra DMA data out commands	181
5.5.5 Ultra DMA CRC rules	185
5.5.6 Series termination required for Ultra DMA	186
5.6 Timing	187
5.6.1 PIO data transfer	187
5.6.2 Multiword data transfer	188
5.6.3 Ultra DMA data transfer	189
5.6.4 Power-on and reset	202
CHAPTER 6 Operations	203
6.1 Device Response to the Reset	204
6.1.1 Response to power-on	204
6.1.2 Response to hardware reset	205
6.1.3 Response to software reset	207
6.1.4 Response to diagnostic command	208
6.2 Power Save	209
6.2.1 Power save mode	209
6.2.2 Power commands	210
6.3 Defect Management	211
6.3.1 Spare area	211
6.3.2 Alternating defective sectors	211
6.4 Read-Ahead Cache	213
6.4.1 Data buffer configuration	214
6.4.2 Caching operation	214
6.4.3 Usage of read segment	216
6.5 Write Cache	222
Glossary	225
Acronyms and Abbreviations	229
Comment Form	231
Spine	233

Fujitsu MHN2150AT Manual/User Guide - Page 74

Spindle motor control, phase to U-phase, U-phase

Page 74 highlights