S T 3 3 2 2 1 A M E D A L I S T SEAGATE Native| Translation ------+-----+-----+----- Form 3.5"/SLIMLINE Cylinders | 6253| 781| 1024 Capacity form/unform 3227/ MB Heads 4| 16| | 16 Seek time / track 11.0/ 1.7 ms Sector/track | 63| 63| 63 Controller ULTRA ATA Precompensation Cache/Buffer 128 KB MULTI-SEGMEN Landing Zone Data transfer rate 16.000 MB/S int Bytes/Sector 512 33.300 MB/S ext UDMA Recording method PRML 16/17,ZBR operating | non-operating -------------+-------------- Supply voltage 5/12 V Temperature *C 5 55 | -40 60 Power: sleep W Humidity % | standby 0.9 W Altitude km | idle 4.9 W Shock g 10 | 75 seek 9.1 W Rotation RPM 5400 read/write W Acoustic dBA 30 spin-up W ECC Bit MTBF h 300000 Warranty Month 36 Lift/Lock/Park YES Certificates ********************************************************************** L A Y O U T ********************************************************************** SEAGATE ST38641A INSTALLATION GUIDE J2 40 pin I/O Cable Connection | pin-20 removed | +--------- |---------+-------1-/---------\ TOP (HDA) -+::::::::::*::::::::1| : : : : | 0 0 0 0 |-- +--------------------+8|-|-|-|-+-5-G-G-12+ BOTTOM | | | | Master ON, Slave OFF --+ | | | Slave Present (when Master ON) ----+ | | Cable Select (when Slave OFF) ----+ | | Reserved ------+ | Limit capacity --------+ Limit Capacity jumper sets the default cylinder translation to 4092 to solve issues with certain BIOS that only auto-detect. Total available sectors are still at full capacity as reported via Identify Drive data words 52 - 61. Third party partitioning software may be needed to achieve full capacity if this option jumper is used. ********************************************************************** J U M P E R S ********************************************************************** SEAGATE ST38641A INSTALLATION GUIDE Jumper settings =============== Master/slave configuration -------------------------- You must establish a master/slave relationship between two drives that are attached to a single AT bus. You can configure a drive to be a master or slave by setting the master/slave jumpers. These drives support master/slave configuration using the cable select option. This requires a special daisy-chain cable that grounds pin 28 (CSEL) on one of its two drive connectors. If you attach the drive to the grounded CSEL connector, it becomes a master. If you attach the drive to the ungrounded CSEL connector, it becomes a slave. To use this option, the host system and both drives must support cable select, and both drives must be configured for cable select. To configure this drive for cable select, install a jumper. For the master drive to recognize the slave drive using the DASP- signal, the slave drive must assert the DASP- signal at power up, and the master drive must monitor DASP- at power up. Alternate capacity jumper ------------------------- Some older computers may "hang" if their BIOS detects a hard drive that has more than 4,092 cylinders at startup. To allow these computers to recognize the ST38641A, the ST36531A, the ST34321 or the ST33221A, these drives include a capacity-limiting jumper, which sets the drive's default translation geometry to 4,092 cylinders. This limits the drive's capacity to 2.1 Gbytes, unless third-party software is used. Identify Drive command ---------------------- The Identify Drive command (command code ECH) transfers information about the drive to the host following power up. The data is organized as a single 512-byte block of data. All reserved bits or words should be set to zero. Parameters listed with an "x" are drive-specific or vary with the state of the drive. Note. If the alternate capacity jumper is installed on these drives, the drive capacity is reduced in word 1 to 4,092 cylinders. J2 40 pin I/O Cable Connection | pin-20 removed | +--------- |---------+-------1-/---------\ TOP (HDA) -+::::::::::*::::::::1| : : : : | 0 0 0 0 |-- +--------------------+8|-|-|-|-+-5-G-G-12+ BOTTOM | | | | Master ON, Slave OFF --+ | | | Slave Present (when Master ON) ----+ | | Cable Select (when Slave OFF) ----+ | | Reserved ------+ | Limit capacity --------+ Limit Capacity jumper sets the default cylinder translation to 4092 to solve issues with certain BIOS that only auto-detect. Total available sectors are still at full capacity as reported via Identify Drive data words 52 - 61. Third party partitioning software may be needed to achieve full capacity if this option jumper is used. ********************************************************************** I N S T A L L ********************************************************************** SEAGATE ST38641A MEDALIST INSTALLATION GUIDE Notes on installation ===================== Installation direction ---------------------- horizontally vertically +-----------------+ +--+ +--+ | | | +-----+ +-----+ | | | | | | | | | +-+-----------------+-+ | | | | | | +---------------------+ | | | | | | | | | | | | | | | | | | +---------------------+ | +-----+ +-----+ | +-+-----------------+-+ +--+ +--+ | | | | +-----------------+ The drive will operate in all axis (6 directions). Drive mounting -------------- You can mount the drive in any orientation using four screws in the side-mounting holes or four screws in the bottom-mounting holes. Important mounting precautions: ------------------------------- - Allow a minimum clearance of 0.030 inches (0.76 mm) around the entire perimeter of the drive for cooling. - Use only 6 -32 UNC mounting screws. - Do not insert the mounting screws more than 0.25 inches (6.25 mm) into the mounting holes. - Do not overtighten the mounting screws (maximum torque: 3 inch-lb). - Do not use a drive interface cable that is more than 18 inches long. ATA interface ------------- These drives use the industry-standard ATA task file interface that supports 16-bit data transfers. It supports ATA programmed input/output (PIO) modes 0, 1, 2, 3 and 4; multiword DMA modes 0, 1 and 2; and Ultra DMA modes 0, 1 and 2. The drive also supports the use of the IORDY signal to provide reliable high-speed data transfers. You can use a daisy-chain cable to connect two drives to a single AT host bus. For detailed information regarding the ATA interface, refer to the draft of AT Attachment with Packet Interface Extension (ATA/ ATAPI-4), NCITS T13 1153D, subsequently referred to as the Draft ATA-4 Standard. ********************************************************************** F E A T U R E S ********************************************************************** SEAGATE ST38641A MEDALIST INSTALLATION GUIDE Introduction ------------ The Medalist 8641 (ST38641A), Medalist 6531 (ST36531A), Medalist 4321 (ST34321A), Medalist 3221 (ST33221A) and Medalist 2110 (ST32110A) provide the following key features: - Low power consumption - Quiet operation - Support for S.M.A.R.T. drive monitoring and reporting - High instantaneous (burst) data-transfer rates (up to 33.3 Mbytes per second) using Ultra DMA mode 2 - Full-track multiple-sector transfer capability without local processor intervention - 128-Kbytes cache - State-of-the-art caching and on-the-fly error-correction algorithms - Support for Read Multiple and Write Multiple commands - Support for autodetection of master/slave drives that use cable select (CSEL) - These drives use MR recording heads and PRML technology, which provides the drives with increased areal density. Drive specifications -------------------- Unless otherwise noted, all specifications are measured under ambient conditions, at 25*C, and nominal power. For convenience, the phrases the drive and this drive are used throughout this manual to indicate the ST38641A, ST36531A, ST34321A, ST33221A and the ST32110A. Note. DOS systems cannot access more than 528 Mbytes on a drive unless 1) the host system supports and is configured for LBA addressing or for extended CHS addressing, 2) the host system contains a specialized drive controller, or 3) the host system runs BIOS translation software. Contact your Seagate (r) repre-sentative for details. LBA Mode -------- When addressing either drive in LBA mode, all blocks (sectors) are consecutively numbered from 0 to n - 1, where n is the number of guaranteed sectors as defined above. Supported CHS translation geometries ------------------------------------ These drives support any translation geometry that satisfies all of the following conditions: - Sectors per track - 63 - Heads - 16 The ST38641A logical cylinders are: Logical cylinders=16,809,660 The ST36531A logical cylinders are: Logical cylinders=12,706,470 The ST34321A logical cylinders are: Logical cylinders=8,404,830 The ST33221A logical cylinders are: Logical cylinders=6,303,024 The ST32110A logical cylinders are: Logical cylinders= 4,124,736 Internal data-transfer rate (Mbits per second max) 140 I/O data-transfer rate (Mbytes per second max) 16.6 (PIO mode 4 with IORDY) 16.6 (multiword DMA mode 2) 33.3 (Ultra DMA mode 2) Interleave 1:1 Cache buffer (Kbytes) 128 Seek time --------- All seek times are measured using a 486 AT computer (or faster) with a 8.3 MHz I/O bus. The measurements are taken with nominal power at 25*C ambient temperature. All times are measured using drive diagnostics. Power Specifications -------------------- The drive receives DC power (+5V or +12V) through a four-pin standard drive power connector. Power consumption ----------------- Power requirements for the drives are listed in the table on page 9. Typical power measurements are based on an average of drives tested under nominal conditions, using 5.0V input voltage at 25*C ambient temperature. Spinup power is measured from the time of power-on to the time that the drive spindle reaches operating speed. During seek mode, the read/write actuator arm moves toward a specific position on the disc surface and does not execute a read or write operation. Servo electronics are active. Seek mode power represents the worst case power consumption, using only random seeks with read or write latency time. This mode is not typical and is provided for worst-case information. Read/Write power and current are measured with the heads on track, based on a 16-sector write followed by a 32-msec delay, then a 16-sector read followed by a 32-msec delay. Operating power and current are measured using 40 percent random seeks, 40 percent read/write mode (1 write for each 10 reads), and 20 percent drive inactive. Idle mode power is measured with the drive up to speed, with servo electronics active, and with the heads in a random track location. During Standby mode, the drive accepts commands, but the drive is not spinning, and the servo and read/write electronics are in power-down mode. Conducted noise --------------- Input noise ripple is measured at the host system power supply across an equivalent 80-ohm resistive load on the +12 volt line or an equivalent 15-ohm resistive load on the +5 volt line. - Using 12-volt power, the drive is expected to operate with a maximum of 120 mV peak-to-peak square-wave injected noise at up to 10 MHz. - Using 5-volt power, the drive is expected to operate with a maximum of 100 mV peak-to-peak square-wave injected noise at up to 10 MHz. Note. Equivalent resistance is calculated by dividing the nominal voltage by the typical RMS read/write current. Voltage tolerance ----------------- Voltage tolerance (including noise): 5V 5% and 12V 10% Active mode. The drive is in Active mode during the read/write and seek operations. Idle mode. The buffer remains enabled, and the drive accepts all commands and returns to Active mode any time disc access is necessary. Standby mode. The drive enters Standby mode when the host sends a Standby Immediate command. If the host has set the standby timer, the drive can also enter Standby mode automatically after the drive has been inactive for a specifiable length of time. The standby timer delay is established using a Standby or Idle command. In Standby mode, the heads are parked and the spindle is at rest. The drive accepts all commands and returns to Active mode any time disc access is necessary. Sleep mode. The drive enters Sleep mode after receiving a Sleep command from the host. The heads are parked and the spindle is at rest. The drive leaves Sleep mode after it receives a Hard Reset or Soft Reset from the host. After receiving a reset, the drive exits Sleep mode and enters Active mode with all current translation parameters intact. Standby timers. Each time the drive performs an Active function (read, write or seek), the standby timer is reinitialized and begins counting down from its specified delay times to zero. If the standby timer reaches zero before any drive activity is required, the drive makes a transition to Standby mode. In both Idle and Standby mode, the drive accepts all commands and returns to Active mode when disc access is necessary. Shock ------ All shock specifications assume that the drive is mounted securely with the input shock applied at the drive mounting screws. Shock may be applied in the X, Y or Z axis. Operating shock --------------- These drives comply with the performance levels specified in this document when subjected to a maximum operating shock of 10.0 Gs (based on half-sine shock pulses of 11 msec, as specified in MIL-STD-202F). Shocks are not to be repeated more than two times per second. Nonoperating shock ------------------ The nonoperating shock level that the drive can experience without incurring physical damage or degradation in performance when sub-sequently put into operation is 75 Gs (based on nonrepetitive halfsine shock pulses of 11 msec duration) or 200 Gs (based on nonrepetitive halfsine shock pulses of 2 msec duration). Shock pulses are defined by MIL-STD-202F. Vibration --------- All vibration specifications assume that the drive is mounted securely with the input vibration applied at the drive mounting screws. Vibration may be applied in the X, Y or Z axis. Operating vibration ------------------- The following table lists the maximum vibration levels that the drive may experience while meeting the performance standards specified in this document. 5-22 Hz 0.20-inch displacement (peak to peak) 22-350 Hz 0.50 Gs acceleration (zero to peak) Nonoperating vibration ---------------------- The following table lists the maximum nonoperating vibration that the drive may experience without incurring physical damage or degradation in performance when put into operation. 5-22 Hz 0.10-inch displacement (peak to peak) 22-350 Hz 5.0 Gs acceleration (zero to peak) Drive acoustics --------------- Drive acoustics are measured as overall A-weighted acoustic sound power levels (no pure tones). All measurements are generally consistent with ISO document 7779. Sound power measurements are taken under essentially free-field conditions over a reflecting plane. For all tests, the drive is oriented with the cover facing upward. For the seeking mode, the drive is placed in seek only. The number of seeks per second is defined by the following equation: Number of seeks per second=0.4/(average latency+average access time) Safety certification -------------------- The drives are recognized in accordance with UL 1950 and CSA C22.2 (950) and meet all applicable sections of IEC950 and EN 60950 as tested by TUV North America. Electromagnetic Compatibility ----------------------------- Hard drives that display the CE marking comply with European Union requirements specified in Electromagnetic Compatibility Directives. Testing is performed to standards EN50082-1 and EN55022-B. Seagate uses an independent laboratory to confirm compliance with the EC directives specified in the previous paragraph. Drives are tested in representative end-user systems. Although CE-marked Seagate drives comply with the directives when used in the test systems, we cannot guarantee that all systems will comply with the directives. The drive is designed for operation inside a properly designed enclosure, with properly shielded I/O cable (if necessary) and terminators on all unused I/O ports. Computer manufacturers and system integrators should confirm EMC compliance and provide CE marking for their products. Australian C-Tick If this model has the C-Tick marking, it complies with the Australia/New Zealand Standard AS/NZS3548 1995 and meets the Electromagnetic Compatibility (EMC) Framework requirements of Australia's Spectrum Management Agency (SMA). FCC verification ---------------- These drives are intended to be contained solely within a personal computer or similar enclosure (not attached as an external device). As such, each drive is considered to be a subassembly even when it is individually marketed to the customer. As a subassembly, no Federal Communications Commission verification or certification of the device is required. Seagate Technology, Inc. has tested this device in enclosures as described above to ensure that the total assembly (enclosure, disc drive, motherboard, power supply, etc.) does comply with the limits for a Class B computing device, pursuant to Subpart J, Part 15 of the FCC rules. Operation with noncertified assemblies is likely to result in interference to radio and television reception. Radio and Television Interference. This equipment generates and uses radio frequency energy and if not installed and used in strict accordance with the manufacturer's instructions, may cause interference to radio and television reception. This equipment is designed to provide reasonable protection against such interference in a residential installation. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause interference to radio or television, which can be determined by turning the equipment on and off, you are encouraged to try one or more of the following corrective measures: - Reorient the receiving antenna. - Move the device to one side or the other of the radio or TV. - Move the device farther away from the radio or TV. - Plug the computer into a different outlet so that the receiver and computer are on different branch outlets. If necessary, you should consult your dealer or an experienced radio/television technician for additional suggestions. You may find helpful the following booklet prepared by the Federal Communications Commission: How to Identify and Resolve Radio-Television Interference Problems. This booklet is available from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402. Refer to publication number 004-000-00345-4. Handling and static-discharge precautions ----------------------------------------- After unpacking, and before installation, the drive may be exposed to potential handling and electrostatic discharge (ESD) hazards. Observe standard static-discharge precautions. A grounded wrist-strap is preferred. Handle the drive only by the sides of the head/disc assembly. Avoid contact with the printed circuit board, all electronic components and the interface connector. Do not apply pressure to the top cover of the drive. Always rest the drive on a padded antistatic surface until you mount it in the host system. S.M.A.R.T. ---------- S.M.A.R.T. provides nearterm failure prediction for disc drives. When S.M.A.R.T. is enabled, the drive monitors predetermined drive attributes that are susceptible to degradation over time. If selfmonitoring determines that a failure is likely, S.M.A.R.T. makes a status report available to the host. Not all failures are predictable. S.M.A.R.T. predictability is limited to the attributes the drive can monitor. For more information on S.M.A.R.T. commands and implementation, see the Draft ATA-4 Standard. These drives are shipped with S.M.A.R.T. features disabled. You must have a recent BIOS or software package that supports S.M.A.R.T. to enable the feature. The table below shows the S.M.A.R.T. command codes that these drives use. ********************************************************************** G E N E R A L ********************************************************************** SEAGATE ATA-INTERFACE ATA Interface Reference Manual 36111-001, Rev. C 21 May 1993 1993 Seagate Technology, Inc. All rights reserved Publication Number: 36111-001, Rev. C Introduction ------------ This manual describes Seagate Technology s implementation of the AT Attachment (ATA) interface, an intelligent hard disc drive interface for use in personal computer systems. This manual includes supported ATA interface commands, command execution, translation methodology, caching, power management, signal conventions, line specifications, and interpretations of error conditions. These interface descriptions are based on the draft proposed American National Standard (dpANS) ATA Interface Revision 4.0. For information on a particular Seagate ATA interface drive (including any drive-unique features not listed in this document), refer to the product manual for the specific drive. Advantages of the ATA interface ------------------------------- The ATA interface is a natural extension of the ISA system bus. Most of the signals and circuitry necessary for the interface are already present in the host system. The interface is easily implemented into the design of an ISA or EISA system with little or no extension required in the system software. It is for this reason that the ATA interface standard has gained such wide acceptance in the personal computer industry. The ATA interface is designated as a logic-level interface, and responds to high-level commands from the host. The drive itself is an intelligent device with an embedded controller that interprets and executes the commands sent from the host. After command execution, the drive reports information on successful command completion, any error conditions and all parameters appropriate to drive status queries. Origins and implementation history ---------------------------------- The ATA interface has evolved rapidly since its initial design by Compaq Corporation. After refining the basic ATA interface concepts and circuitry, Compaq Corporation worked with Imprimis (now a part of Seagate) to build the first ATA interface drive. At this stage, the interface was far from being an accepted standard. However, it was a natural extension of the ATA I/O bus, and gained industry-wide acceptance because most of the necessary framework needed for the implementation was already present in the host machine. Initially, there were no industry-wide standards for implementing the ATA interface, leaving manufacturers free to extend and improve upon it. In the latter part of 1988, a Common Access Method (CAM) committee was established to develop such standards. Their results were adopted by the American National Standards Institute (ANSI) with the intent of creating a common ATA command specification. The ANSI standard for the ATA interface now provides specifications for mandatory commands, signal conventions, register descriptions and other information necessary for basic compatibility across manufacturers and platforms. The current ANSI specification includes provisions for extended features such as caching and power management, while also providing options for vendor-specific enhancements. Nomenclature and conventions ---------------------------- Throughout this manual, the term master refers to Drive 0 in a two-drive system; the term slave refers to Drive 1, if present. Signals may be asserted or negated. A signal that is asserted as a higher positive voltage is referred to as active high. A signal that is asserted as a lower (positive) voltage is referred to as active low, and is indicated by a minus sign (-) following the signal name. ATA cables and connectors ------------------------- The standard ATA interface cable is a 40-conductor nonshielded cable. The cable should be no more than 18 inches (457 mm) long, with connectors that provide strain relief and are keyed at pin 20. Two types of connectors are used on Seagate s ATA-capable drives: a 40-pin connector for 5.25-and 3.5-inch drives, and a 50-pin connector for 2.5- and 1.8-inch drives. Connector used on 5.25- and 3.5-inch drives ------------------------------------------- The standard connector used on 5.25- and 3.5-inch drives has 40 pin positions in 2 rows of 20 pins each, on 100 mil (0.1 inch) centers. Pin 20 is removed for keying. The mating cable connector is a keyed, 40-pin-position nonshielded female connector with 2 rows of 20 contacts on 100 mil centers. For 5.25- and 3.5-inch drives, power is supplied to the drive through a separate 4-conductor cable. Seagate recommends using 40-pin connectors such as AMP part number 1-499496-0, Du Pont part number 66900-040, or equivalent. Connector used on 2.5-inch drives --------------------------------- The ATA connector on 2.5-inch drives has 50 pin positions. In addition to the key pin, one pair of pins is removed, and the four end pins are used as jumpers for master/slave configurations. This leaves 44 pins to supply power and conduct signals to and from the drive. The signal pins (1 through 40) are assigned the same signals as in the 40-pin connector used for 5.25- and 3.5-inch drives. Power is supplied through pins 41, 42 and 43. The mating cable connector is a 44-conductor nonshielded connector with 2 rows of 22 female contacts on 0.079-inch (2 mm) centers. We recommend using a connector such as Molex part number 87259- 4413 or equivalent for 2.5-inch drives attached to flexible cables or printed circuit cables. Some Seagate 2.5-inch drives are designed to support the industry-standard MCC direct-mounting specifications (see drive product manual for details). MCC-compatible connectors (such as Molex part number 87368-442 x or equivalent) and mounting hardware must be used with these drives in fixed-mounting applications. System configurations --------------------- Seagate recommends using the ATA interface in one of the following configurations: - If the system motherboard has its own ATA connector, then you can connect the drive interface cable directly to the system motherboard. - If the system does not have a built-in ATA connector, then attach the interface cable to a Seagate ST07A or ST08A host adapter installed in a system expansion slot. Signal / Pin descriptions ------------------------- Note. Not all Seagate drives support the full complement of ATA signals listed below. To determine the complete set of signals that are supported by a particular Seagate drive, see the product manual for that drive. Data lines to and from host. These comprise the 16-bit tristate, bidirectional data bus between host and drive. The lower 8-bits of host data (0 7) are used for register and ECC access. All 16 bits are used for data transfers. 19 Ground Grounding pin 20 Key An unused pin, which is clipped off at the drive to allow keyed cable attachment. 21 DMARQ DMA Request (optional) 22 Ground Grounding pin 23 DIOW Drive I/O write strobe. Rising edge clocks data from the host data bus to a drive register or data port. 24 Ground Grounding pin 25 DIOR Drive I/O read strobe. Falling edge enables data from a drive register or data port to host data bus. 26 Ground Grounding pin 27 IORDY I/O Channel Ready (optional) - a tristate signal. 28 SPSYNC or CSEL (optional) SPSYNC is an interdrive clock signal sent from the master drive to the slave drive to allow the slave to synchronize its spindle motor to the master drive's spindle motor. CSEL is used to differentiate master from slave in a two-drive system. 29 DMACK DMA Acknowledge (optional) 30 Ground Grounding pin 31 INTRQ A tristate signal used to interrupt the host system. Asserted only when the drive has a pending interrupt, the drive is selected, and the host has cleared nIEN in the Device Control register. 32 IOCS16 A tristate signal that, when active, indicates to the host system that the 16-bit data port has been addressed and that the drive is prepared to send or receive a 16-bit data word. 33 DA1 Drive I/O address line 1: a 3-bit binary coded address asserted by the host to access a register or data port in the drive. 34 PDIAG Passed diagnostics. Used by slave to signal to master drive that slave has passed its internal diagnostics. 35 DA0 Drive I/O address line 0 (see DA1 above). 36 DA2 Drive I/O address line 2 (see DA1 above). 37 CS1FX Drive I/O chip select decoded from host address lines. When active, one of the registers in the Command Block is selected. 38 CS3FX Drive I/O chip select decoded from host address lines. When active, one of the registers in the Control Block is selected. 39 DASP Dual purpose pin: 1) When drive is slave (SLV), this pin is used during power up to signal to the master that a slave is present. 2) At all other times, the signal is active when the drive is executing a command, and can be used by the host I/O adapter to send an activity signal to an LED. 40 Ground Grounding pin Interface handshaking --------------------- The main handshaking signals between the drive and the host are the busy bit (BSY) and the data request bit (DRQ) (in the status register) and the interrupt (INTRQ) signal. They can be set in one of the following ways: - Any reset will cause BSY to be set. - Writing a command to the command register will also set BSY. The BSY bit is used to indicate that the controller is busy and should not be accessed. The DRQ bit is used to control the data transfer to and from the controller. The host can read/write the data register only when the DRQ bit is set to 1. The INTRQ signal is generated by the drive to interrupt the host. For example, during a Read Sector command, the drive generates an INTRQ to the host whenever a sector is ready for the host to read. No INTRQ is generated immediately after completion of a Read command. The number of interrupts equals the number of sectors read. During a Write Sector command, the drive generates an INTRQ whenever the drive requests data from the host (except for the first sector). The drive also generates an interrupt immediately after completion of a Write command. The number of interrupts equals the number of sectors written. ATA interface I/O registers --------------------------- The drive communicates with the host system through an I/O register that routes the input and output data between registers. These registers are selected by codes on the CS1FX, CS3FX, DA2, DA1, DA0, DIOR (read) and DIOW (write) lines from the host. The I/O register routes data between 14 registers. Ten registers are used for commands to the drive or status reports from the drive, one register is used for data, and three registers are used for control and alternate status. These registers can be divided into two groups: Command Block registers and Control Block registers. PC-AT I/O port address: 3F6H This register contains the same information as the Status register in the command block. The only difference is that reading this register does not imply interrupt acknowledge or reset a pending interrupt. This register can be read at any time. PC-AT I/O port address: 1F7H This eight-bit register contains the host command. When this register is written, the drive immediately begins executing the command. The host must ensure that the BSY bit in the Status register is set to 0. All other setup registers must be written to (with appropriate values) before the command register can be written. PC-AT I/O port address: 1F5H This register contains the most significant bits of the starting cylinder address for any disc access. At the completion of a command, this register is updated to reflect the current cylinder address. With logical block addressing, this register contains bits 23 through 16 of the LBA. Cylinder Low register PC-AT I/O port address: 1F4H This register contains the eight least significant bits of the starting cylinder address for any disc access. At the completion of a command, this register is updated to reflect the current cylinder address. With logical block addressing, this register contains bits 15 through 8 of the LBA. Data register PC-AT I/O port address: 1F0H This is the register through which: - All data is passed during Read and Write commands. - The sector table is transferred during format commands. The host can only access this register when the DRQ bit in the status register is set to 1. All transfers use 16-bit words, except the ECC bytes transferred during Read Long and Write Long commands, which use 8 bit bytes. Drive/Head register The host selects between the master and slave drives based on the DRV bit in the drive/head register. When the DRV bit is not set, the master drive is selected, and when the DRV bit is set to 1, the slave drive is selected. Seagate drives are designated as master and slave by setting the appropriate jumpers. Error register PC-AT I/O port address: 1F1H This register contains the status from the last command executed by the drive, or it may contain a diagnostic code. At the completion of any command except Execute Drive Diagnostic, the contents of this register are valid when ERR=1 in the Status register. Following a power on, reset, or completion of an Execute Drive Diagnostic command, this register contains a diagnostic code. PC-AT I/O port address: 1F2H This register specifies the number of sectors of data to be transferred during read/write sector commands. The value contained in the register is decremented every time a sector is transferred. A value of zero specifies 256 sectors. When executing the Initialize Drive Parameters or Format commands, this register defines the number of sectors per track. This register is used by the power mode commands to set timers. Sector Number register PC-AT I/O port address: 1F3H This register contains the starting sector number for any disc access. At the completion of a command, this register is updated to reflect the last sector transferred correctly, or the sector on which an error occurred. The sectors are numbered sequentially, starting with 1. With logical block addressing, this register contains bits 7 through 0 of the logical block address (LBA).