Samsung spinpoint v40 manual Servo System, Read and Write Operations, Read Channel

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DISK DRIVE OPERATION

5.3 Servo System

The Servo System controls the position of the read/write heads and holds them on track during read/write operations. The Servo System also compensates for MR write/read offsets and thermal offsets between heads on different surfaces and for vibration and shock applied to the drive.

The SpinPoint V40 is an Embedded Sector Servo System. Positioning information is radially located in 192 evenly spaced servo sectors on each track.

Radial position information can be provided from these sectors for each data head, 192 times per revolution. Because the drive incorporates multiple data zones and each zone has a different bit density, split data fields are necessary for optimal use of the non-servo area of the disk. The servo area remains phase-coherent across the surface of the disk, even though the disk has various data zones. The main advantage of the Embedded Sector Servo System is that it eliminates the problems of static and dynamic offsets between heads on different surfaces. The SpinPoint V40 Servo System is classified as a digital servo system because track- following and seek control, bias cancellation, and other typical tasks are done in a Digital Signal Processor (DSP).

The Servo system has three modes of operation: track-following mode, settle mode, and velocity control mode.

1.Track-following mode is used when heads are “on-track.” This is a position loop with an integrator in the compensation.

2.Settle mode is used for all accesses; head switches, short-track seeks and long-track seeks. Settle mode is a position loop with velocity damping. Settle mode does not use feed forward.

3.Velocity control mode is used for acceleration and deceleration of the actuator for a seek of two or more tracks. A seek operation of this length is accomplished with a velocity control loop. The drive’s ROM stores the velocity profile in a look-up table.

The feed forward compensation is used while the bandwidth of the control loop is kept low.

5.4 Read and Write Operations

The following two sections describe the read and write channels.

5.4.1The Read Channel

The drive has one read/write head for each of the data surfaces. The signal path for the Read Channel starts at the read/write heads. When the magnetic flux transitions recorded on a disk pass under the head, they generate low-amplitude, differential output voltages. The read/write head transfers these signals to the flexible circuit’s amplifier, which amplifies the signal.

The flexible circuit transmits the pre-amplified signal from the HDA to the PCBA. The EPRML channel on the PCBA shapes, filters, detects, synchronizes, and decodes the data from the disk. The Read/Write IC then sends the resynchronized data output to the SID2001 DSP & Interface/Disk Controller.

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SpinPoint V40 Product Manual

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Contents Spinpoint SpinPoint V40 Product Manual Table of Contents Ervo S Ystem EAD and W Rite O Perations Irmware F EaturesSmart Programming Requirements Protocol OverviewTiming 107 Maintenance PrecautionsService and Repair General InformationTable of Figures Page User Definition Manual OrganizationScope Computer Message Commands and MessagesTerminology and Conventions Format C/SReference Key Features IntroductionDescription Standards and Regulations Hardware RequirementsSpecification Summary SpecificationsPhysical Specifications Logical ConfigurationsPerformance Specifications Power Requirements 28.71Environmental Specifications SV6003H SV6014H SV8004HReliability Specifications Mtbf POHInstallation Space RequirementsUnpacking Instructions MountingOrientation 2Mounting Dimensions in Millimeters Clearance 3Mounting-Screw ClearanceAT-Bus Interface Connector Cable ConnectorsDC Power Connector VentilationSpinPoint V40 Product Manual Jumper Block Configurations Options for Jumper Block Configuration Drive Installation 7DC Power Connector and AT-Bus Interface Cable ConnectionsSystem Startup Procedure ParameterSystem Setup DC Spindle Motor Assembly Head / Disk Assembly HDABase Casting Assembly Disk Drive OperationExploded Mechanical View Voice Coil Motor and Actuator Latch Assemblies Disk Stack AssemblyHead Stack Assembly Air Filtration SystemDigital Signal Process and Interface Controller Drive ElectronicsAT Disk Controller 2SID2001 AT Controller Block Diagram Host Interface Control Block Buffer Control Block Disk Control BlockSpinPoint V40 Product Manual Disk ECC Control Block Power ManagementRead/Write IC Frequency SynthesizerAsymmetry Correction Circuitry ASC Time Base GeneratorAutomatic Gain Control Analog Anti-Aliasing Low Pass Filter3Read/Write 88C5200 Servo System Read and Write OperationsRead Channel Firmware Features Write ChannelRead Caching Write Caching Multi-burst ECC Correction Defect ManagementAutomatic Defect Allocation SmartBlank Signal Conventions Signal SummaryPhysical Interface Signal Descriptions Intrq Drive Interrupt DMACK- DMA AcknowledgeDmarq DMA Request IOCS16- Drive 16-bit I/OPDIAG- Passed Diagnostics RESET- Drive ResetIordy I/O Channel Ready SD3 SD8 SD6 SD9 SD5SD4 SD2Drive Drive HostDIR Bit Conventions Logical InterfaceGeneral EnvironmentSpinPoint V40 Product Manual Control Block Registers Command Block Registers2 I/O Register Address N N N A a aDrive Address Register 3F7h Control Block Register DescriptionsAlternate Status Register 3F6h Device Control Register 3F6hError Register 1F1h Command Block Register DescriptionsFeatures Register 1F1h Data Register 1F0hCylinder High Register 1F5h Command Register 1F7hSector Count Register 1F2h Cylinder Low Register 1F4hStatus Register 1F7h BSY Drdy DWF DSC DRQ Corr IDX ERRAt Command Register Descriptions Command Parameter Used SpinPoint V40 Product Manual Check Power Mode 98h, E5h Execute Device Diagnostics 90hDownload Micro Code 92h Flush Cache E7h Format Track 50hIdentify Device ECh Word Content Description XxxxCapabilities Command set supported 95-128 0000h Reserved 129-159 Vendor specific 160-255 Idle 97h,E3h Idle Immediate 95h,E1hInitialize Device Parameters 91h Read Buffer E4h Read Long 22hwith retry, 23h without retryRead Multiple Command C4h Read Native Max Address F8h Read Sectors 20hwith retry, 21hwithout retryRead Verify Sectors 40hwith retry, 41hwithout retry Recalibrate 1xhSeek 7xh Set Features EFh ModeNormal outputs InputsLBA BSY Drdy DRQ ERRDescription Set Multiple Mode C6h Sleep 99h, E6hSmart disable operation D9h Standby 96h,E2hSmart B0h Smart enable/disable attribute autosave D2h Smart enable operations D8hSmart execute off-line immediate D4h Smart read data D0h Byte DescriptionsValue Definition Off-line data collection capabilitySmart return status DAh Smart capabilitySmart read log sector D5h Smart save attribution value D3hWrite Buffer E8h Standby 96h, E2hStandby Immediate 94h, E0h Write DMA CAhWrite Multiple Command C5h Write Sectors 30hwith retry, 31hwithout retrySpinPoint V40 Product Manual Reset Response Error PostingProgramming Requirements Command Error Register Status Register BBKStandby mode Power ConditionsSleep mode Idle modeNormal mode PIO Data in Commands Protocol OverviewPIO Data Out Commands PIO Read CommandPIO Read Aborted Command BSY=0 DRDY=1 BSY=1 PIO Write CommandPIO Write Aborted Command BSY=0 DRQ=1 BSY=1 DRQ=0Non-Data Commands DMA Data Transfer Commands Aborted DMA Command Initialize DMA Reset DMA Status BSY=0 BSY=1BSY=1 BSY=0 Timing Register transfersDIOR-/DIOW Write PIO timing parameters Mode PIO data transfersAddr valid See note T1 t2 DIOR-/DIOW Multiword DMA data transfer DIOR-/DIOWMultiword DMA timing parameters Mode Ultra DMA data transfer Initiating an Ultra DMA data in burstUltra DMA data burst timing requirements 19Ultra DMA data burst timing requirementsSustained Ultra DMA data in burst 5Sustained Ultra DMA data in burstHost pausing an Ultra DMA data in burst 6Host pausing an Ultra DMA data in burstDevice terminating an Ultra DMA data in burst 7Device terminating an Ultra DMA data in burst 100Host terminating an Ultra DMA data in burst 8Host terminating an Ultra DMA data in burstInitiating an Ultra DMA data out burst 9Initiating an Ultra DMA data out burst 102Sustained Ultra DMA data out burst 10Sustained Ultra DMA data out burstDevice pausing an Ultra DMA data out burst 11Device pausing an Ultra DMA data out burst 104Host terminating an Ultra DMA data out burst 12Host terminating an Ultra DMA data out burstDevice terminating an Ultra DMA data out burst 13Device terminating an Ultra DMA data out burst 106Maintenance Precautions Service And RepairGeneral Information
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