S T 3 2 4 3 0 N D H A W K 2 L P SEAGATE
NO MORE PRODUCED Native| Translation
------+-----+-----+-----
Form 3.5"/SLIMLINE Cylinders 3892| | |
Capacity form/unform 2147/ 2600 MB Heads 9| | |
Seek time / track 9.0/ 1.7 ms Sector/track | | |
Controller SCSI2 DI/FAST Precompensation
Cache/Buffer 512 KB SEGMENTED Landing Zone
Data transfer rate 5.000 MB/S int Bytes/Sector 512
10.000 MB/S ext SYNC
Recording method RLL 1/7 operating | non-operating
-------------+--------------
Supply voltage 5/12 V Temperature *C 5 55 | -40 70
Power: sleep W Humidity % |
standby W Altitude km |
idle 6.5 W Shock g |
seek W Rotation RPM 5411
read/write W Acoustic dBA
spin-up W ECC Bit
MTBF h 800000
Warranty Month 60
Lift/Lock/Park YES Certificates CSA,FCC,IEC950,UL1950,VDE
**********************************************************************
L A Y O U T
**********************************************************************
SEAGATE ST32430N INSTALLATION GUIDE 77767499 REV. A, 9/1995
+---------------------------------------------------------+ 1
| +---1 J5 |XXPower
| +---+ |XX
| |
| |XX1
| |XX
| |XXJ1
++ |XX
++LED |XXI/O
| |XX
| |XX
| |XX
|+-+ |XX
|| | |XX
|| | J6 J2 |XX
|+-1 8--------1 |XX
| +--------+ |XX
+---------------------------------------------------------+
**********************************************************************
J U M P E R S
**********************************************************************
SEAGATE ST32430N/ND INSTALLATION GUIDE 77767499 REV. A 9/1995
Jumper Setting
==============
REAR VIEW +------ 5V
| +---- GND
(TOP) | | +-- GND
| | | + 12V
+------------------------1+ +-------+
-+:::::::::::::::::::::::::+-+O O O O+-
+-------------------------+ +-------+
50pin I/O Cable
Connection
RIGHT SIDE VIEW
---------------
Suggested part number for the unusual J2 jumper is Molex 52747-0211
(Seagate P/N 77679052).
+-J1 TOP (HDA)
|X+------------+--------+-----PWA------------------Front of drive
+-+ |12345678|J2
+--------+
TE +Terminator PWR -+||||||+- TE
TE +Terminator PWR --+||||+-- Start Delay (12 secs * ID) DS
| SS ---+||+--- Motor Start ME
PE | Parity Enable ----++---- Write Protect WP
|
|
Terminator Power-source Table
-----------------------------
1 2 1 2 1 2
+---- +---- +----
|X o |o X |o o Position A
|X o |o X |xxx
+------ +------ +-------
Drive Supplies Drive Supplies Bus Supplies
Bus Own Drive
J2 Jumper Setting
-----------------
TE (Applies to "N" models only)
On With the jumper installed, the On-board (non-removable)
terminator circuits are enabled (connected to the I/O lines).
Default is jumper installed.
Off Terminator circuits are disabled.
NOTE
ND models do not have terminators on the drive PCB, so these jumpers
are not applicable.
TP TP
Off Off No terminator power is connected to drive terminators
or SCSI bus I/O pin 26.
On Off Drive supplies its own terminator power only.
Jumper on this position is factory default for "N"
models only.
Off On Drive supplies power to I/O pin 26 of SCSI bus; none to
internal terminators. When drives have differential I/O
circuits, a jumper on the right TP position may be needed
to power external termina-tors (see system documentation).
The "ND" model drives have differential I/O circuits which
have no terminator circuits on the drive.
On On Drive supplies terminator power to itself (internal
connection) and to I/O pin 26 of SCSI bus. This is a
legal jumper setting.
TP Position A ("N" family models only)
--------------------------------------
On This horizontally positioned jumper across the two TP
positions nearest PCB edge, connects terminator power
from SCSI bus I/O pin 26 to the drive's internal terminators.
Off See above explanations for TP jumpers.
DS ME
Off Off Spindle starts immediately after power up - Default setting.
Off On Drive spindle does not start until Start Unit command
received from host.
On Off Spindle Startup is delayed by SCSI ID times 12 seconds
after power is applied, i.e., drive 0 spindle starts
immediately when DC power connected, drive 1 starts
after 12 second delay, drive 2 starts after 24 second
delay, etc.
On On Drive spindle starts when Start Unit command received
from host. Delayed start feature is overridden and does
not apply when ME jumper is installed.
WP
On Entire drive is write protected.
Off Drive is not write protected. Default is no WP jumper installed.
PE
On Parity checking and parity error reporting by the drive is
enabled.
Off Drive does not report result of parity checking to host.
Default is a PE jumper installed.
SS
Off/On Reserved. Default is no jumper installed.
LEFT SIDE VIEW J5
TOP (HDA) +--1+ +-+ Back of
Front-------PWA--------------------------------+:::+---+X|J1 drive
of drive +---+ +-+
ID1--+||
ID2---+| If these jumpers
ID4----+ are used, the ID
jumpers in front
view ARE NOT USED
J5 SCSI ID
-----------
SCSI address selection
----------------------
Make sure that the SCSI bus address jumper(s) are properly set for
the bus address assigned to the drive. Typically the primary boot
device is set to ID 0, and the subsequent SCSI drives are jumpered
in ascending order. Bus addresses 0 through 6 should be used (the
host adapter usually uses address 7). If the drive LED shows no
on/off activity when the host is trying to communicate with it,
an incorrect bus address selection at the drive should be suspected.
+----------+-----------------------+
| SCSI ID | Jumpers |
| | ID4 | ID2 | ID1 |
+----------+-------+-------+-------+
| 0 | OPEN | OPEN | OPEN |
+----------+-------+-------+-------+
| 1 | OPEN | OPEN | CLOSED|
+----------+-------+-------+-------+
| 2 | OPEN | CLOSED| OPEN |
+----------+-------+-------+-------+
| 3 | OPEN | CLOSED| CLOSED|
+----------+-------+-------+-------+
| 4 | CLOSED| OPEN | OPEN |
+----------+-------+-------+-------+
| 5 | CLOSED| OPEN | CLOSED|
+----------+-------+-------+-------+
| 6 | CLOSED| CLOSED| OPEN |
+----------+-------+-------+-------+
| 7 | CLOSED| CLOSED| CLOSED|
+----------+-------+-------+-------+
FRONT VIEW J6
TOP (HDA) +-----1+
---PWA-----------------------------+::::::+-----
+------+
ID4 -+||||+- RESERVED
ID2 --+||+-- Remote LED (pin-3 +5V)
ID1 ---++--- Spindle Sync (pin-6 REF
SIG+)
J6 SCSI ID
-----------
+----------+-----------------------+
| SCSI ID | Jumpers |
| | ID4 | ID2 | ID1 |
+----------+-------+-------+-------+
| 0 | OPEN | OPEN | OPEN |
+----------+-------+-------+-------+
| 1 | OPEN | OPEN | CLOSED|
+----------+-------+-------+-------+
| 2 | OPEN | CLOSED| OPEN |
+----------+-------+-------+-------+
| 3 | OPEN | CLOSED| CLOSED|
+----------+-------+-------+-------+
| 4 | CLOSED| OPEN | OPEN |
+----------+-------+-------+-------+
| 5 | CLOSED| OPEN | CLOSED|
+----------+-------+-------+-------+
| 6 | CLOSED| CLOSED| OPEN |
+----------+-------+-------+-------+
| 7 | CLOSED| CLOSED| CLOSED|
+----------+-------+-------+-------+
If these ID jumpers are used, the ID jumpers shown in left side view
ARE NOT USED.
Bus termination
---------------
Model "N" drives have an active terminator IC that is permanently
installed, but can be enabled or disabled by a jumper plug.
If you are installing a single drive, the terminator IC must
remain enabled. If you are installing multiple hard disc drives,
disable the termination IC on all the drives but the one connected
to the end of the SCSI I/O cable.
Model numbers that end in "ND" have differential I/O circuits.
These drives have no provisions for terminators on the drive PCB.
The system manufacturer must provide some external means of I/O
line termination. The "ND" model drives can provide power for
external terminators if the TP jumper is installed on the last
position on the right end of J2.
Optional parity bit enable
--------------------------
Some systems require parity bit checking. Consult the system
documentation for the specific requirements. Jumper-installed
enables parity reporting by the SCSI bus.
Write precompensation and reduced write current
-----------------------------------------------
Not required on Seagate SCSI Interface drives covered by this manual.
Drive configuration
-------------------
Each disc drive has one or more option select header connectors on
the back, side or front where jumper plugs are installed to select
the way that the drive is to be configured or to select its ID on
the I/O bus.
Hawk 2LP family N/ND models (50 pin SCSI I/O)
---------------------------------------------
On Model N/ND drives either J6 (on the front of the drive) or J5
(on the side behind the DC Power connector) may be used to set the
drive ID. To avoid possible incorrect ID setting, do not use both
J5 and J6 for ID selection.
LED
---
These pins used to connect a cable for a remote LED indicator.
Pin 3 (top, nearest HDA), the anode connection, connects in the
drive to the +5V supply through a pull-up resistor. Pin 4 (bottom),
the cathode connection connects in the drive to signal common through
the emitter-collector junction of a transistor switch that controls
the LED on/off condition.
**********************************************************************
I N S T A L L
**********************************************************************
SEAGATE ST32430/31230N/ND31221N INSTALLATION GUIDE 77767499 REV.A,95
Notes On Installation
=====================
Disc drive mounting
-------------------
Do not touch the connector pins or any PCB components without
observing static-discharge precautions. Always handle the drive
by the frame only.
The drive may be mounted in any orientation.
horizontally vertically
+-----------------+ +--+ +--+
| | | +-----+ +-----+ |
| | | | | | | |
+-+-----------------+-+ | | | | | |
+---------------------+ | | | | | |
| | | | | |
| | | | | |
+---------------------+ | +-----+ +-----+ |
+-+-----------------+-+ +--+ +--+
| |
| |
+-----------------+
The drive will operate in all axis (6 directions).
Mount to host system chassis using four 6-32 UNC screws.
Three mounting holes are in each side and four in the bottom of the
drive. The maximum length that the screws should extend into the side
chassis mounting holes is 0.15 inch (3.81 mm), and 0.20 inch (5.1 mm)
into bottom holes, measured from the outer surface of the chassis.
The minimum thread engagement for all mounting screws is 0.12 inch
(3.0 mm). Tighten the screws evenly to a maximum torque of 6 in-lb
(.675 NM). Do not over tighten or force when screw does not seem
to screw in easily (threads not correctly engaged).
Verify that all connections between the drive and the host system
are correctly installed. Most cables have a contrasting color stripe
indicating pin 1.
Verify option select and drive ID select jumpers and installation
of terminator enable jumper where applicable.
Do not power up the host system until the drive is mounted and the
system cover is replaced.
Connect DC power connector to the drive.
Replace the Host System cover.
Turn on DC power.
Mechanical installation
-----------------------
After setting up the drive configuration the drive must be
mechanically installed into the host system and the power and I/O
cables attached. Previously mentioned precautions should be observed.
SCSI interface cable connection
-------------------------------
Models Hawk 2LP family are SCSI interface drives. System connection
is via a 50 pin SCSI connector. Some cables have a contrasting color
stripe on one edge to indicate pin 1. Strain relief is recommended
at the cable in drives using cables. Do not block system cooling air
flow in routing of cables.
Read/Write head auto-park
-------------------------
Seagate disc drives described herein mentioned in this drive park
the heads automatically at power off. This feature requires no
operator intervention.
Grounding
---------
Signal ground (PCB) and HDA ground are connected together in the
Hawk 2LP family drives and cannot be separated by the user.
The equipment in which the drive is mounted is connected
directly to the HDA and PCB with no electrically isolating
shock mounts. If it is desired for the system chassis to not be
connected to the HDA/PCB ground, the systems integrator or user
must provide a nonconductive (electrically isolating) method of
mounting the drive in the host equipment.
**********************************************************************
F E A T U R E S
**********************************************************************
SEAGATE ST32430/31230N/ND 31231N INSTALLATION GUIDE 77767499, REV.A
General
-------
Safety Instructions
-------------------
The disk drives are to be installed in a cuatomer supplied enclosure
where the surrounding air does not exceed 50*C.
CMOS configuration
------------------
SCSI drives should not be defined in the CMOS. The SCSI host adapter
uses its own BIOS to handle the Input/Output procedures. The CMOS
setting for SCSI drive is either drive type zero, or the no drive
installed option.
Low-Level formatting
--------------------
All Hawk 2LP family drive models are low-level formatted at the
factory and do not require this step during installation. If an
installed drive is low-level formatted, all user data will be lost.
Note: Seagate Technology assumes no liability for lost user data.
Partitioning and high level formatting
--------------------------------------
A drive can be subdivided into "partitions" which behave as
individual drives within the system. Consult the system documentation
for instructions on partitioning and high level formatting.
Information is also available in bookstores and libraries.
SCSI interface drives
---------------------
The SCSI interface handles both drive geometry and defect
management internally. The "no drive installed" option is selected
for systems with SCSI drives.
All SCSI interface drives are low-level formatted at the factory.
You may wish to low-level format the drive to optimize its perform-
ance for your system. Consult the controller documentation for
information on low-level formatting. Partitioning and high-level
formatting can be done through DOS by way of the FDISK utility for
partitioning, and FORMAT for high-level formatting. Consult your
DOS manual for FORMAT and FDISK command options.
**********************************************************************
G E N E R A L
**********************************************************************
SEAGATE SCSI
Interface requirements
----------------------
How to use this interface manual
This specification is designed to provide a universal detailed
description of the SCSI interface for those disc drive products whose
Product Manuals (Volume 1) do not contain the details of how the
SCSI interface is implemented by that drive.
Note: Volume 1 Product Manuals have tables in Section 11 that specify
which SCSI-1 or SCSI-2/SCSI-3 features they implement, what the
default parameters are for the various features they implement and
which parameters are changeable and which are not. No method exists
at present to inform an initiator if a target supports "SCSI-3"
features as opposed to only SCSI-2 features. A few "SCSI-3" features
are supported by Seagate drives, but no attempt has been made herein
to differentiate between SCSI-2 and "SCSI-3" features. Therefore,
when an Inquiry command reports what the ANSI approved version of the
drive is, it reports either SCSI-1 or SCSI-2, where "SCSI-2" means
SCSI-2 features plus some "SCSI-3" features.
No attempt is made in this universal specification to specify which
descriptions or tables apply to SCSI-1 and which to SCSI-2 or SCSI-3.
The combination of this general specification with the details in
the Section 11 tables of the individual drive Product Manual (Volume
1) provides a description of the individual drive implementation of
the SCSI interface. This interface manual is not intended to be
stand-alone text on SCSI-1 or SCSI-2/SCSI-3 features.
Reference must be made back to the individual drive Product Manuals
to find out what are SCSI-1 and what are SCSI-2/SCSI-3 features.
This specification is Volume 2 of a set of manuals that is made up of
separate drive Product Manuals (Volume 1) and this manual. This
Volume 2 Manual is referenced by other Volume 1 Product Manuals
representing the drives listed below.
Product Manuals for the following models reference this volume:
ST11200N/ND/NC, ST1980N/ND/NC, ST1830N, ST1950N, ST3500N, ST3600N,
ST3610N/ND/NC, ST12400N/ND/NC, ST12400 Wide, ST11900N/ ND/NC,
ST31200N/ND/NC, ST31200 Wide, ST11950N/ND, ST11950W/WD,
ST12450W/WD, ST12550N/ND, ST12550W/WD, ST15150N/ND, ST15150W/WD,
ST3655N, ST3550W, ST3390N and ST3285N, ST32430N/ND/NC,
ST32430W/WD/WC, ST15230N/ND/NC, ST31250N/ND, ST31250W/WD/WC,
ST32151N, ST31051N, ST32550N/ND, ST32550W/WD/WC, ST3471N,
ST410800N/ND, ST410800W/WD.
General interface description
-----------------------------
This Product Manual describes the Seagate Technology, Inc. subset of
the SCSI (Small Computer Systems Interface) as implemented on the
Seagate built disc drives listed above. The interface is compatible
with the SCSI Interface Specifications of the ANSI SCSI-1 standard,
the ANSI SCSI-2 Standard and the common command set (CCS) document,
Revision 4.B. The disc drives covered by this Product Manual are
classified as "Intelligent" peripherals.
The Seagate SCSI interface described herein consists of a 9 or 18 bit
bidirectional bus (8 data + 1 parity or 16 data + 2 parity) plus 9
control signals supporting multiple initiators, disconnect/
reconnect, self configuring host software, automatic features that
relieve the host from the necessity of knowing the physical
architecture of the target (logical block addressing is used), and
some other miscellaneous features.
The SCSI physical interface uses either single ended drivers and
receivers or differential drivers and receivers and uses asynchronous
or synchronous communication protocols. The bus interface transfer
rate for asynchronous or synchronous is given in individual disc
drive Volume 1 Product Manuals. The bus protocol supports multiple
initiators, disconnect/reconnect, additional messages plus 6 byte and
10 byte Command Descriptor Blocks. Unless specified otherwise in the
individual drive Product Manuals (Vol. 1), the disc drive is always a
target, and never an initiator. For certain commands, which may or
may not be supported by a particular drive model, the drive must act
as an initiator, but does not otherwise do so. For purposes of this
specification, "disc drive" may be substituted for the word "target"
wherever "target" appears.
GLOSSARY
--------
Arbitration - SCSI bus phase wherein SCSI devices try to gain control
of the SCSI bus to operate as an initiator or target
Byte - This term indicates an 8 bit hexadecimal construction.
Command Descriptor Block (CDB) - The structure used to communicate
requests from an initiator to a target.
Connect - The function that occurs when an initiator selects a target
to start an operation.
Disconnect - The function that occurs when a target releases control
of the SCSI bus, allowing it to go to the Bus Free phase.
FRU (Field Replaceable Unit) - An assembly that is believed faulty
based on test results. A value of 00h indicates an unknown cause or
the end of a list of known possible causes. Nonzero values have
product unique meanings.
Initiator - A SCSI device (usually a host system) that requests an
operation to be performed by another SCSI device.
Intermediate Status - A status code sent from a target to an
initiator upon completion of each command, except the last command,
in a set of linked commands.
I/O Process - An I/O process consists of one initial connection and
zero or more reconnections, all pertaining to a single command or
group of linked commands. More specifically, the connection(s)
pertain to a nexus as defined below in which one or more command
descriptor blocks are usually transferred. An I/O process begins with
the establishment of a nexus. An I/O process normally ends with the
BUS Free phase following successful transfer of a COMMAND COMPLETE,
ABORT, ABORT TAG, or CLEAR QUEUE message. An I/ O process also ends
when a hard RESET condition occurs, an unexpected BUS FREE phase
occurs, or when the BUS FREE phase occurs following a BUS DEVICE
RESET message.
I T nexus - A nexus prior to the successful receipt of an IDENTIFY
message, at which time the nexus is changed to an I T L nexus. (See
glossary word "Nexus").
I T L nexus - A nexus that exists between an initiator and a Logical
Unit. This relationship replaces the prior I T nexus. (See glossary
word "Nexus").
I T L Q nexus - A nexus between an initiator, a Logical Unit, and a
queue tag following the successful receipt of one of the QUEUE
messages. This relationship replaces the prior I T L nexus. (See
glossary word "Nexus").
Logical Unit - A physical device or virtual device addressable
through a target. The disc drive is a target but also a Logical Unit.
Logical Unit Number - An encoded three bit identifier for the logical
unit. The disc drive is considered Logical Unit number zero.
LSB - Least significant byte
MSB - Most significant byte
ms - millisecond
LUN - Logical unit number
mm - Millimetre
SCSI bus
--------
This manual discusses only the "logical" and timing characteristics
of the SCSI system and interface. The SCSI bus physical
characteristics (voltages, connector configurations, pinouts, etc.)
are given in the individual disc drive Product Manuals (Volume 1)
Section "Interface requirements", which covers all of the interface
requirements and SCSI features supported by the drive described in
the particular Product Manual being referenced.
Communication on the SCSI Bus is allowed between only two SCSI
devices at a time. Some Seagate drives support systems with a maximum
of eight SCSI devices including the host computer(s) connected to the
SCSI bus. Some Seagate drives support systems with a maximum of
sixteen SCSI devices on the SCSI bus. Each SCSI device has a SCSI ID
Bit.
The SCSI ID is assigned by installing from 0 to 3 (8 device systems)
jumper plugs or 0-4 (16 device systems) jumper plugs onto a connector
in a binary coded configuration during system configuration. Some
drive models have an interface that includes the SCSI bus ID lines,
so that the host can set the drive ID over the interface. See
individual disc drive Product Manual, Section "Option/configuration
headers".
When two SCSI devices communicate on the SCSI Bus one acts as an
initiator and the other acts as a target. The initiator (typically a
host computer) originates an operation and the target performs the
operation. The disc drive always operates as a target, unless
specified otherwise (i.e., certain commands are supported) in the
individual drive Product Manual.
The Host Adapter/Initiator must be identified by one of the eight
SCSI Device Addresses. Make sure that none of the devices on the SCSI
bus have duplicate addresses. Certain SCSI bus functions are assigned
to the initiator and certain SCSI bus functions are assigned to the
target. The initiator will select a particular target. The target
will request the transfer of Command, Data, Status or other
information on the data bus.
Information transfers on the data bus are interlocked and follow a
defined REQ/ACK Handshake protocol. One byte of information will be
transferred with each handshake. Synchronous data transfers do not
require a one for one interlocking of REQ/ACK signals, but the total
number of REQ pulses in a particular data transfer event must equal
the total number of ACK pulses.
The disc drive supports single initiator, single target; single
initiator, multiple target; multiple initiator, single target; or
multiple initiator, multiple target bus configurations.
SCSI bus signals
----------------
There are ten control and eighteen data signals, as listed below:
- BSY
- C/D
- MSG
- DIFFSENS
- SEL
- I/O
- REQ
- DB(7-0, P); DB(15-8,P1)
- ACK
- ATN
- RST
Some drive models have a single 80 pin I/O connector that contains
additional interface lines that carry drive configuration select
signals. These are peculiar to certain drives and are not SCSI
standard signals. These are described in the drive model's Volume 1
Product manual, but not here. The 28 SCSI standard signals are
described as follows:
BSY (Busy) - An "OR-tied" signal to indicate the bus is being used.
SEL (Select) - A signal used by an initiator to select a target, or
by a target to reselect an initiator.
C/D (Control/Data) - A signal driven by a target to indicate whether
Control or Data information is on the Data Bus. Assertion indicates
Control.
I/O (Input/Output) - A signal driven by a target to control the
direction of data movement on the Data Bus with respect to an
initiator. Assertion indicates input to the initiator. This signal
also distinguishes between Selection and Reselection phases.
MSG (Message) - A signal driven by a target during the Message phase.
REQ (Request) - A signal driven by a target to indicate a request for
REQ/ACK data transfer handshake.
ACK (Acknowledge) - A signal driven by an initiator to indicate an
acknowledgment for a REQ/ACK data transfer handshake.
ATN (Attention) - A signal driven by an initiator to indicate the
Attention condition. It is used to request to send a message out to
the target. If an initiator asserts ATN while asserting SEL it
indicates to the target that the initiator supports messages other
than command complete.
RST (Reset) - An "OR-tied" signal that indicates the Reset condition.
DIFFSENS (Differential Sense) - When the drive has differential SCSI
I/O circuits, the DIFFSENS signal disables the drive s differential
driver/receiver circuits if the SCSI I/O cable is plugged in upside
down, or if a single-ended SCSI I/O cable is plugged into a
differential I/O drive. Disabling the differential I/O drivers/
receivers is necessary to prevent burning them out if a grounded I/O
line is connected to any of the differential circuit outputs, which
are at a positive voltage (+2 V or +3 V) when not disabled.
DB(7-0,P) and DB(15-8,P1)
(Data Bus) - Sixteen data bit signals, plus parity bit signals form a
Data Bus. DB(7) is the most significant bit and has the highest
priority during the Arbitration phase (on both eight and sixteen
device systems). Bit number significance, and priority decrease
downward to DB(0), and then from DB15 down to DB8 (DB0 is higher than
DB15). A data bit is defined as one when the signal is asserted and
is defined as zero when the signal is negated.
Data parity DB(P) and DB(P1) is odd - The use of parity is a system
option. The disc drive always checks parity on the data bits, but has
the capability to enable/disable parity error reporting to the host.
See configuration selection in the applicable Product Manual. Parity
checking is not valid during the Arbitration phase.
Greater detail on each of the SCSI Bus signals is found in the
following sections.
Drive Select
------------
For SCSI ID selection install drive select jumpers as shown in
configuration selection figure in applicable Product Manual. Refer to
section 10 of the individual drive Product Manual for the location
of the drive select header. The disc drive using the eight bit data
interface can have one of eight ID bits selected by installing 0 to 3
jumpers in a binary coded configuration on the drive select header.
Drives using the 16 bit data interface can have one of sixteen ID
bits selected by installing 0 to 4 jumpers in a binary coded
configuration on the drive select header.
Signal Values
-------------
Signals may assume true or false values. There are two methods of
driving these signals. In both cases, the signal shall be actively
driven true, or asserted. In the case of OR-tied drivers, the driver
does not drive the signal to the false state, rather the bias
circuitry of the bus terminators pulls the signal false whenever it
is released by the drivers at every SCSI device. If any driver is
asserted, then the signal is true. In the case of non-OR-tied
drivers, the signal may be negated. Negated means that the signal may
be actively driven false, or may be simply released (in which case
the bias circuitry pulls it false), at the option of the implementor.
OR-Tied signals
---------------
The BSY and RST signals shall be OR-tied only. In the ordinary
operation of the bus, these signals are simultaneously driven true by
several drivers. No signals other than BSY, RST, and DB(P) are
simultaneously driven by two or more drivers, and any signal other
than BSY and RST may employ OR-tied or non-OR-tied drivers. DB(P)
shall not be driven false during the Arbitration phase. There is
no operational problem in mixing OR-tied and non-OR-tied drivers on
signals other than BSY and RST.
Signal sources
--------------
All SCSI device drivers that are not active sources shall be in the
passive state. Note that the RST signal may be sourced by any SCSI
device at any time. The disc drive functions as a target.
Nonarbitrating system
---------------------
In systems with the Arbitration phase not implemented, the initiator
shall first detect the Bus Free phase and then wait a minimum of a
bus clear delay. Then, except in certain single initiator
environments with initiators employing the single initiator option
the initiator shall assert the desired target's SCSI ID and its own
initiator SCSI ID on the Data Bus. After two deskew delays, the
initiator shall assert SEL.
Arbitrating systems
-------------------
In systems with the Arbitration phase implemented, the SCSI device
that won the arbitration has both BSY and SEL asserted and has
delayed at least a bus clear delay plus a bus settle delay before
ending the Arbitration phase. The SCSI device that won the
arbitration becomes an initiator by releasing I/O. Except in certain
single initiator environments with initiators employing the single
initiator option, the initiator shall set the Data Bus to a value
which is the OR of its SCSI ID bit and the target s SCSI ID bit. The
initiator shall then wait at least two deskew delays and release
BSY. The initiator shall then wait at least a bus settle delay before
looking for a response from the target.
All systems
-----------
In all systems, the target shall determine that it is selected when
SEL and its SCSI ID bit are true and the BSY and I/O signals are
false for at least a bus settle delay. The selected target will
examine the Data Bus in order to determine the SCSI ID of the
selecting initiator unless the initiator employed the single
initiator option. The selected target shall then assert BSY within a
selection abort time of its selection; this is required for correct
operation of the timeout procedure. In systems with parity
implemented, the target shall not respond to a selection if bad
parity is detected. Also, if more than two SCSI ID bits are on the
Data Bus, the target shall not respond to selection. At least two
deskew delays after the initiator detects BSY is asserted, it shall
release SEL and may change the Data Bus.
Single initiator option
-----------------------
Initiators that do not implement the Reselection phase, and do not
operate in the multiple initiator environment, are allowed to set
only the target's SCSI ID bit during the Selection phase. This makes
it impossible for the target to determine the initiator s SCSI ID.
Selection time out procedure
----------------------------
A Selection timeout procedure is specified for clearing the SCSI bus.
If the initiator waits a minimum of a selection timeout delay and
there has been no BSY response from the target, the initiator shall
continue asserting SEL and shall release the Data Bus. If the
initiator has not detected BSY to be asserted after at least a
selection abort time plus two deskew delays, the initiator shall
release SEL allowing the SCSI bus to go to the Bus Free phase. SCSI
devices shall ensure when responding to selection that the selection
was still valid within a selection abort time of their assertion of
BSY. Failure to comply with this requirement could result in an
improper selection (two targets connected to the same initiator,
wrong target connected to an initiator, or a target connected to no
initiator). The disc drive supports systems that implement this
procedure.
Asynchronous information transfer
---------------------------------
The target shall control the direction of information transfer by
means of the I/O signal. When I/O is true, information shall be
transferred from the target to the initiator. When I/O is false,
information shall be transferred from the initiator to the target.
If I/O is true (transfer to the initiator), the target shall first
drive DB(7-0,P)* to their desired values, delay at least one deskew
delay plus a cable skew delay, then assert REQ. DB(7-0,P)* shall
remain valid until ACK is true at the target. The initiator shall
read DB(7-0,P)* after REQ is true, then signal its acceptance of the
data by asserting ACK. When ACK becomes true at the target, the
target may change or release DB(7-0, P)* and shall negate REQ. After
REQ is false the initiator shall negate ACK. After ACK is false, the
target may continue the transfer by driving DB(7-0,P)* and asserting
REQ, as described above.
If I/O is false (transfer to the target) the target shall request
information by asserting REQ. The initiator shall drive DB(7-0,P)* to
their desired values, delay at least one deskew delay plus a cable
skew delay and assert ACK. The initiator shall continue to drive the
DB(7-0,P)* until REQ is false.
When ACK becomes true at the target, the target shall read
DB(7-0,P)*, then negate REQ. When REQ becomes false at the initiator,
the initiator may change or release DB(7-0,P)* and shall negate
ACK. The target may continue the transfer by asserting REQ, as
described above.
Synchronous data transfer
-------------------------
Synchronous data transfer may be used only in the data phase if
previously agreed to by the initiator and target through the message
system. The messages determine the use of synchronous mode by both
SCSI devices and establish a REQ/ACK offset and a transfer period.
The REQ/ACK offset specifies the maximum number of REQ pulses that
can be sent by the target in advance of the number of ACK pulses
received from the initiator, establishing a pacing mechanism. If
the number of REQ pulses exceeds the number of ACK pulses by the
REQ/ACK offset, the target shall not assert REQ until the next ACK
pulse is received. A requirement for successful completion of
the data phase is that the number of ACK and REQ pulses be equal.
The target shall assert the REQ signal for a minimum of an assertion
period. The target shall wait at least the greater of a transfer
period from the last transition of REQ to true or a minimum of a
negation period from the last transition of REQ to false before
asserting the REQ signal.
The initiator shall send one pulse on the ACK signal for each REQ
pulse received. The ACK signal may be asserted as soon as the leading
edge of the corresponding REQ pulse has been received. The initiator
shall assert the ACK signal for a minimum of an assertion period. The
initiator shall wait at least the greater of a transfer period from
the last transition of ACK to true or for a minimum of a negation
period from the last transition of ACK to false before asserting the
ACK signal.
Unit attention condition
------------------------
The disc drive sets up the Unit Attention condition when it stores
(within itself) a Unit Attention condition flag for each device on
the SCSI bus having an initiator relationship with the disc drive,
and this Unit Attention condition persists for each initiator until
the condition is cleared (flag negated) by each initiator
individually. The Unit Attention condition results when one of the
following events occur:
1. A power-on sequence occurs.
2. A reset is generated internally by the disc drive (caused by a
power glitch).
3. A Bus Device Reset message causes the disc drive to reset itself.
4. The RESET I/O line resets the disc drive.
5. An initiator changes one or more of the Mode Select parameters in
the disc drive (these changes could affect one or more of the
other initiators).
6. The inquiry data has been changed.
7. The mode parameters in effect for an initiator have been restored
from nonvolatile memory.
8. An event occurs that requires the attention of the initiator.
9. A Clear Queue message received.
10. The Log parameters are changed. Unit Attention Condition is
posted for all initiators in the system other than the one
that changed the Log Parameters.
The Unit Attention Parameters page (page 00h, bit 4 of byte 2) of the
Mode Select Command controls whether or not a Check Condition Status
is to be reported to affected initiators when a Unit Attention
condition exists. The Unit Attention condition for a particular
initiator is cleared when that initiator does one of the following:
1. It sends a Request Sense Command.
2. It sends any other legitimate command, with the exception
of the Inquiry command. The Inquiry command does not clear the
Unit Attention condition.
When a Unit Attention condition flag is stored in the disc drive
for an initiator, the commands that initiator issues to the disc
drive operate as described in the following paragraphs.
If an initiator sends an Inquiry command to the disc drive when the
disc drive has stored a Unit Attention condition flag for that
initiator before or after the disc drive reports Check Condition
status), the disc drive shall perform the Inquiry command and shall
not clear the Unit Attention condition.
If an initiator sends a Request Sense command to the disc drive when
a Unit Attention condition flag is stored for that initiator (before
or after the disc drive reports Check Condition), the disc drive
shall discard any pending sense data, report the Unit Attention Sense
Key, and clear the Unit Attention condition (negate the flag) for
that initiator.
If an initiator issues a command other than Inquiry or Request Sense
while a Unit Attention condition flag is stored for that initiator,
the disc drive may or may not perform the command and report Check
Condition status, depending on whether or not the Unit Attention bit
is zero or one in the Unit Attention Mode Parameters page (Page 00h,
bit 4 of byte 2). If a Request Sense is issued next, the Unit
Attention condition is reported and cleared (flag negated) as noted
in the preceding paragraph. If another command other than Request
Sense or Inquiry is issued instead, the disc drive shall perform the
command and return the appropriate status. The Unit Attention
condition for the subject initiator is cleared (flag negated) and the
sense data and flag indicating there has been a Unit Attention
condition are lost.