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Fujitsu MHT2030AT Manual/User Guide - Page 55

Air filter, 4.3 Circuit Configuration

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4.3 Circuit Configuration 4.2.4 Air filter There are two types of air filters: a breather filter and a circulation filter. The breather filter makes an air in and out of the DE to prevent unnecessary pressure around the spindle when the disk starts or stops rotating. When disk drives are transported under conditions where the air pressure changes a lot, filtered air is circulated in the DE. The circulation filter cleans out dust and dirt from inside the DE. The disk drive cycles air continuously through the circulation filter through an enclosed loop air cycle system operated by a blower on the rotating disk. 4.3 Circuit Configuration Figure 4.1 shows the power supply configuration of the disk drive, and Figure 4.2 shows the disk drive circuit configuration. (1) Read/write circuit The read/write circuit consists of two circuits; read/write preamplifier (PreAMP) and read channel (RDC). The PreAMP consists of the write current switch circuit, that flows the write current to the head coil, and the voltage amplifier circuit, that amplitudes the read output from the head. The RDC is the read demodulation circuit using the Modified Extended Partial Response (MEEPR), and contains the Viterbi detector, programmable filter, adaptable transversal filter, times base generator, data separator circuits, RLL (Run Length Limited) encoder and servo demodulation circuit. (2) Servo circuit The position and speed of the voice coil motor are controlled by 2 closed-loop servo using the servo information recorded on the data surface. The servo information is an analog signal converted to digital for processing by a MPU and then reconverted to an analog signal for control of the voice coil motor. The MPU precisely sets each head on the track according on the servo information on the media surface. (3) Spindle motor driver circuit The circuit measures the interval of a PHASE signal generated by counterelectromotive voltage of a motor and controls the motor speed comparing target speed. C141-E192-02EN 4-3

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

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4.3

Circuit Configuration

C141-E192-02EN

4-3

4.2.4 Air filter

There are two types of air filters:

a breather filter and a circulation filter.

The breather filter makes an air in and out of the DE to prevent unnecessary

pressure around the spindle when the disk starts or stops rotating.

When disk

drives are transported under conditions where the air pressure changes a lot,

filtered air is circulated in the DE.

The circulation filter cleans out dust and dirt from inside the DE.

The disk drive

cycles air continuously through the circulation filter through an enclosed loop air

cycle system operated by a blower on the rotating disk.

4.3 Circuit Configuration

Figure 4.1 shows the power supply configuration of the disk drive, and Figure 4.2

shows the disk drive circuit configuration.

(1) Read/write circuit

The read/write circuit consists of two circuits; read/write preamplifier (PreAMP)

and read channel (RDC).

The PreAMP consists of the write current switch circuit, that flows the write

current to the head coil, and the voltage amplifier circuit, that amplitudes the read

output from the head.

The RDC is the read demodulation circuit using the Modified Extended Partial

Response (MEEPR), and contains the Viterbi detector, programmable filter,

adaptable transversal filter, times base generator, data separator circuits,

RLL (Run Length Limited) encoder and servo demodulation circuit.

(2) Servo circuit

The position and speed of the voice coil motor are controlled by 2 closed-loop

servo using the servo information recorded on the data surface.

The servo

information is an analog signal converted to digital for processing by a MPU and

then reconverted to an analog signal for control of the voice coil motor.

The MPU precisely sets each head on the track according on the servo

information on the media surface.

(3) Spindle motor driver circuit

The circuit measures the interval of a PHASE signal generated by counter-

electromotive voltage of a motor and controls the motor speed comparing target

speed.