. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
ST3655 Family:
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
ST3390A, ST3550A, ST3655A
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
AT Interface Drives
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
Product Manual
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
ST3655 Family:
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
ST3390A, ST3550A, ST3655A
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
AT Interface Drives
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
Product Manual
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© 1993 Seagate Technology, Inc. All rights reserved
Publication Number: 36244-003, Rev. A
23 December 1993
Seagate
®
, Seagate Technology® and the Seagate logo are registered
trademarks of Seagate Technology, Inc. Other product names are trademarks or registered trademarks of their owners.
Seagate reserves the right to change, without notice, product offerings
or specifications. No part of this publication may be reproduced in any
form without written permission from Seagate Technology, Inc.
ST3655 Family AT Drives Product Manual, Rev. A iii
Contents
1.0 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Formatted capacity . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 Recommended logical configuration . . . . . . . . . . . 1
1.1.2 Physical organization . . . . . . . . . . . . . . . . . . . 2
1.2 Functional specifications . . . . . . . . . . . . . . . . . . . 2
1.3 Seek time . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3.1 Thermal compensation . . . . . . . . . . . . . . . . . . 3
1.3.2 Multisegmented cache buffer . . . . . . . . . . . . . . . 3
1.4 Start/stop time . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 Typical power-up and power-down sequence . . . . . . . . . 4
1.5.1 Power-up sequence . . . . . . . . . . . . . . . . . . . 4
1.5.2 Power-down sequence . . . . . . . . . . . . . . . . . . 4
1.5.3 Auto-park . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.6 Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.7 Physical dimens ions . . . . . . . . . . . . . . . . . . . . . . 5
1.8 Environmental specifications . . . . . . . . . . . . . . . . . 5
1.8.1 Ambient temperature . . . . . . . . . . . . . . . . . . . 5
1.8.2 Temperature gradient . . . . . . . . . . . . . . . . . . . 5
1.8.3 Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.8.4 Relative humidity . . . . . . . . . . . . . . . . . . . . . 6
1.9 Acoustics . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.10 Shock and vibration . . . . . . . . . . . . . . . . . . . . . 6
1.11 DC power . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.11.1 Input noise . . . . . . . . . . . . . . . . . . . . . . . . 7
1.11.2 Power management . . . . . . . . . . . . . . . . . . . 7
1.11.3 Idle and standby timers . . . . . . . . . . . . . . . . . 7
1.11.4 Power-management modes . . . . . . . . . . . . . . . 8
1.11.5 Power consumption . . . . . . . . . . . . . . . . . . . 9
iv ST3655 Family AT Drives Product Manual, Rev. A
1.12 Agency listings . . . . . . . . . . . . . . . . . . . . . . . 11
1.13 FCC verification . . . . . . . . . . . . . . . . . . . . . . 11
2.0 Configuring and mounting the drive . . . . . . . . . . . . . 13
2.1 Handling and static-discharge precautions . . . . . . . . . 13
2.2 I/O cable and connector . . . . . . . . . . . . . . . . . . 14
2.3 Remote LED connection . . . . . . . . . . . . . . . . . . 15
2.4 Jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.4.1 Jumper sizes . . . . . . . . . . . . . . . . . . . . . . 15
2.4.2 Factory test jumper block (J6) . . . . . . . . . . . . . 15
2.4.3 Master/slave configuration . . . . . . . . . . . . . . . 17
2.5 Cable select option . . . . . . . . . . . . . . . . . . . . . 18
2.6 Spindle synchronization option . . . . . . . . . . . . . . . 20
2.7 Mounting the drive . . . . . . . . . . . . . . . . . . . . . . 22
3.0 AT interface . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.1 Command set . . . . . . . . . . . . . . . . . . . . . . . . 25
3.1.1 Identify Drive command (EC
3.1.2 Set Features command (EF
3.1.3 Sleep command (99
, E6H) . . . . . . . . . . . . . . 29
H
) . . . . . . . . . . . . . 27
H
) . . . . . . . . . . . . . 29
H
3.2 AT Interface connector pin assignments . . . . . . . . . . 29
Appendix. Timing diagrams . . . . . . . . . . . . . . . . . . . . 31
ST3655 Family AT Drives Product Manual, Rev. A v
Figures
Figure 1. Typical startup current profile . . . . . . . . . . . . . . . 10
Figure 2. AT interface connector . . . . . . . . . . . . . . . . . . 14
Figure 3. Configuration jumper s . . . . . . . . . . . . . . . . . . . 16
Figure 4. Connecting cable-selected drives . . . . . . . . . . . . . 19
Figure 5. Connecting synchronized drives . . . . . . . . . . . . . . 21
Figure 6. Spindle synchronization timing . . . . . . . . . . . . . . 21
Figure 7. Recommended mounting orientations . . . . . . . . . . . 23
Figure 8. Mounting dimensions . . . . . . . . . . . . . . . . . . . 24
Figure 9. AT interface connector pin assignments . . . . . . . . . 30
Figure 10. Programmed I/O timing without IORDY . . . . . . . . . 31
Figure 11. Programmed I/O timing with IORDY . . . . . . . . . . . 32
Figure 12. Multiword DMA timing . . . . . . . . . . . . . . . . . . 33
ST3655 Family AT Drives Product Manual, Rev. A 1
1.0 Specifications
1.1 Formatted capacity
The drive is low-level formatted at the factory. You cannot low-level
format the drive.
ST3390A ST3550A ST3655A
Formatted capacity (Mbytes*) 341.311 452.415 528.482
Total sectors 666,624 883,624 1,032,192
* One megabyte equals one million bytes.
1.1.1 Recommended logical configuration
You can operate the drive using many different logical configurations,
provided the number of sectors per track does not exceed 256. However,
in DOS the number of sectors per track must be less than or equal to 63.
When establishing the logical configuration, set the number of sectors
per track and the number of heads to satisfy the following relationship:
16
≤
(sectors per track)(heads) ≤ 4,096
When you configure the drive in CMOS, the total sectors cannot exceed
the physical capacity of the drive. The total sectors is determined by the
following formula:
total sectors = (logical heads) (logical sectors per track) (logical cylinders)
To maximize the capacity of the drive, the following geometry is recom-
mended:
ST3390A ST3550A ST3655A
Cylinders 768 1,018 1,024
Read/write heads 14 14 16
Sectors per track 62 62 63
The drive is configured in translation mode. You can verify the number
of cylinders, sectors per track and heads by using the Identify Drive (EC
command. See Section 3.1.1 for details about the Identify Drive command.
H
)
2 ST3655 Family AT Drives Product Manual, Rev. A
1.1.2 Physical organization
ST3390A ST3550A ST3655A
Read/write heads 3 5 5
Servo heads 1 1 1
Discs 2 3 3
1.2 Functional specifications
Interface AT
Zone Bit Recording method RLL (1,7)
External data burst transfer rate
(Mbytes per sec)
Internal data transfer rate
(Mbits per sec)
Spindle speed (RPM) 4,500 ± 0.5%
Cache size (Kbytes) 256
Bytes per sector 512
Recording density, max (BPI) 53,192**
Track density (TPI) 3,000**
* The drives achieve this external transfer rate when using programmed
I/O with IORDY, as shown in Figure 11 on page 32.
** The ST3550A has a recording density of 52,602 bits per inch and a
track density of 2,400 tracks per inch.
11.1*
21.6 to 36.56
1.3 Seek time
Seek time is a true statistical average of at least 5,000 measurements of
seek time. All measurements are under nominal conditions of temperature and voltage with the drive mounted horizontally. The specifications
in the table below are defined as follows:
• Track-to-track seek time is the average of all possible single-track
seeks in both directions.
• Average seek time is measured by executing seeks in both directions
between random cylinders.
• Full-stroke seek time is half the time needed to seek from track 0 to
the maximum track and back to track 0.
ST3655 Family AT Drives Product Manual, Rev. A 3
Track-to-track
seek time
3.5 msec typ
4.0 msec max
Note. Host overhead varies between systems and cannot be specified.
Drive internal overhead is measured by issuing a no-motion seek.
Overhead is typically less than 0.5 msec.
Average
seek time
12.0 msec typ
14.0 msec max
Full-stroke seek
time
30.0 msec typ
32.0 msec max
Average
latency
6.67 msec
1.3.1 Thermal compensation
The thermal compensation feature compensates for position offset of the
selected head because of variations in temperature. The drive automatically compensates for thermal offset every 30 seconds for the first 30
minutes of operation and every 1.5 minutes thereafter. The drive performs this automatic compensation while executing a command from the
computer.
You can pre-empt the automatic compensation by issuing a Recalibrate
command. The drive performs a thermal compensation, sets a timer and
waits 2 minutes before performing the automatic compensation again.
Thermal compensation increases the execution time of the command
during which it is performed by 100 msec (typ) to 350 msec (max).
1.3.2 Multisegmented cache buffer
The drive uses the cache buffer to improve performance by eliminating
access times under certain conditions. The cache buffer contains four
64-Kbyte segments of RAM (one for writing and three for reading) for a
total capacity of 256 Kbytes.
Read look-ahead. The drive uses the read segments to store additional
logical sectors, after the last requested sector, into a buffer before the
additional sectors are requested by the computer. The cache buffer
stores data from the start of a read until the buffer segment is full, or until
another command is received from the computer.
Write immediate. The drive uses the write segment to store write
commands and data. After the drive receives all the data for the command, it issues a write complete. Then, the drive writes the data to the
disc.
Write merging. The drive accepts contiguous write commands and
executes them as one command.
4 ST3655 Family AT Drives Product Manual, Rev. A
1.4 Start/stop time
Within 20 seconds after DC power is applied, the drive is ready. Within
15 seconds after DC power is removed, the drive spindle stops rotating.
1.5 Typical power-up and power-down sequence
The typical power-up and power-down sequences assist you in evaluating the drive’s performance; they are not performance specifications.
1.5.1 Power-up sequence
1. Power is applied to the drive.
2. When power is applied, the LED is on for about 1 second.
3. The spindle motor reaches operating speed in about 4 seconds.
4. The arm-lock solenoid releases the arm, making an audible sound.
5. The drive performs velocity adjustment seeks.
6. The heads are positioned ov er track 0 and the drive is ready.
1.5.2 Power-down sequence
Caution. Do not move the drive until the motor has come to a complete
stop.
1. The power is turned off.
2. Within 3 seconds, the motor begins to spin down.
3. The read/write heads automatically move to the shipping zone, which
is inside the maximum data cylinder.
4. The arm-lock solenoid locks the arm, making an audible sound. This
completes the power-down sequence.
1.5.3 Auto-park
Upon power-down, the read/write heads automatically move to the
shipping zone. The heads park inside the maximum data cylinder and
the arm-lock solenoid engages, making an audible sound. When power
is applied, the heads recalibrate to track 0.
ST3655 Family AT Drives Product Manual, Rev. A 5
1.6 Reliability
Read error rates are measured with automatic retries and data correction
with ECC enabled and all flaws re-allocated. The mean time between
failures (MTBF) is measured at nominal power at sea level and an
ambient temperature of 40°C.
Nonrecoverable read errors 1 per 10
Seek errors 1 per 10
MTBF 250,000 power-on hours
Service life 5 years
13
bits transferred
7
physical seeks
1.7 Physical dimensions
The mounting dim ensions are shown in Figure 8 on page 24.
Height, max 1.00 inch (25.4 mm)
Width, max 4.02 inches (102.1 mm)
Depth, max 5.77 inches (146.6 mm)
Weight 1.5 lb (0.68 Kg)
1.8 Environmental specifications
1.8.1 Ambient temperature
Operating 5°C to 55°C (41°F to 131°F)
Nonoperating –40°C to 65°C (–40°F to 149°F)
1.8.2 Temperature gradient
Operating 20°C per hour (36°F per hour)
Nonoperating 30°C per hour (54°F per hour)
1.8.3 Altitude
Operating –1,000 ft to 10,000 ft (–305 m to 3,048 m)
Nonoperating –1,000 ft to 40,000 ft (–305 m to 12,192 m)
6 ST3655 Family AT Drives Product Manual, Rev. A
1.8.4 Relative humidity
Operating 8% to 80% noncondensing
Maximum wet bulb 26°C (79°F)
Maximum operating
gradient
Nonoperating 5% to 95% noncondensing
10% per hour
Maximum wet bulb 26°C (79°F)
1.9 Acoustics
Sound pressure is measured from 1 meter above the drive top cover at
idle.
Sound pressure, typ (dBA) 34
Sound pressure, max (dBA) 38
1.10 Shock and vibration
All shock and vibration specifications assume that the drive is mounted
in a recommended orientation (see Figure 7 on page 23) with the input
levels measured at the drive mounting screws. Shock measurements are
based on an 11 msec, half sine wave shock pulse, not to be repeated
more than twice per second.
During normal operating shock and vibration, there is no physical damage to the drive or performance degradation. During nonoperating shock
and vibration, the read/write heads are positioned in the shipping zone.
Operating Nonoperating
Shock 2 Gs 75 Gs
5–22 Hz vibration 0.020-inch
displacement
22–500 Hz vibration 0.50 Gs 4.00 Gs
0.020-inch
displacement
ST3655 Family AT Drives Product Manual, Rev. A 7
1.11 DC power
Except during the write procedure, you can turn off and turn on power to
the drive in any sequence without losing data or damaging the drive. If
you turn off the power during the write procedure, you may lose the data
currently being written.
1.11.1 Input noise
+5V +12V
Voltage tolerance
(including noise)
Input noise frequency
(max)
Input noise
(max, peak-to-peak)
± 5% ± 5%
25 MHz 25 MHz
100 mV 240 mV
1.11.2 Power management
This drive uses power-management modes to reduce its overall power
consumption. The level of drive activity for each power-management
mode is described below.
You can customize the power-management modes using the AT interface commands that control the power modes. These commands are
described in the
number 36111-
Note. If you install one of these power-management drives as a slave to
a master drive that does not support power management (for
example, a Seagate ST1239A drive), do not use power-management commands on either drive.
Seagate ATA Interface Reference Manual
xxx
.
, publication
1.11.3 Idle and standby timers
The drive can enter the Idle or Standby modes by either of two methods:
• The computer can send either the Idle Immediate command or the
Standby Immediate command.
• The idle timer or the standby timer can count down to zero.
At power-on, the drive sets the idle timer to enter the Idle mode after
5 seconds of inactivity; the standby timer is disabled. You can set the
timer delays using the system setup utility. During each read, write or
8 ST3655 Family AT Drives Product Manual, Rev. A
seek, the drive reinitializes the idle timer and begins counting down from
the specified delay to zero.
If the idle timer reaches zero before the drive is commanded to read,
write or seek, the drive switches to the Idle mode. Then, if the standby
timer is enabled, the standby timer begins counting down. After the
standby timer has finished counting down, the drive switches to Standby
mode. To set the idle and standby timers, refer to the Idle command in
the
Seagate ATA Interface Reference Manual
ber 36111In both the Idle and Standby modes, the drive accepts all commands and
returns to the Seeking or Read/write modes any time disc access is
necessary.
xxx
.
, publication num-
1.11.4 Power-management modes
The following power-management modes are supported by the drive:
• Spinup. The drive brings the spindle and discs up to operating speed.
Power in this mode is defined as the average power during the first
10 seconds after starting spinup. The drive enters this mode during
startup and from the Standby mode.
• Seeking. The drive moves the read/write heads to a specific location
on the disc surface in preparation for reading or writing the disc.
Read/write electronics are powered down and servo electronics are
active. The power measure during this mode is the average power
while executing random seeks with a 2-revolution (26.6 msec) dwell
between Seek commands.
• Read/write. The drive reads or writes the disc. Read/write electronics
are active and the servo is on track. The drive enters this mode from
the Idle mode.
• Idle. The spindle is spinning and the cache buffer remains enabled,
and the drive accepts all commands and returns to the Seeking or
Read/write modes when it receives a command that requires disc
access.
• Standby. The spindle is stopped, the heads are parked in the landing
zone, the actuator is latched, and some of the drive electronics are
powered down. The drive reports to the computer that it is ready to
access the disc. When the drive receives a command that does not
require disc access, the drive remains in the Standby mode. When
the drive receives a command that requires disc access, it spins up
and performs the command.
ST3655 Family AT Drives Product Manual, Rev. A 9
1.11.5 Power consumption
In the table below, the values apply at the drive power connector. Current
was measured with an RMS DC ammeter.
Read/
Spinup Seeking
Current at +12V
Amps peak 1.90 — — — —
RMS amps typ — 0.408 0.241 0.208 0.025
Watts typ — 4.90 2.90 2.50 0.30
Current at +5V
RMS amps typ — 0.140 0.500 0.130 0.120
Watts typ — 0.70 2.50 0.65 0.60
Power
Total watts typ 7.00 5.60 5.40 3.15 0.90
write Idle Standby
T1
T2
T3
T5
T4
T6
T7
T8
0
1.0
1.7
2.0
0 21 43 65 87
amps
Seconds
10 ST3655 Family AT Drives Product Manual, Rev. A
The startup current profile of each drive is unique. A typical startup
current profile is shown in Figure 1.
Figure 1. Typical startup current profile
T1 Power is applied to the drive.
T2 After a delay, the startup current is applied and the spindle
begins to turn.
T3 The accelerating current is applied, causing the spindle speed to
increase.
T4 The spindle speed is close to the final correct value. The drive
begins to lock in speed-control circuits.
T5 The arm-lock solenoid releases the arm.
T6 The final speed-control lock is achieved.
T7 The drive performs velocity adjustment seeks.
T8 The heads are positioned over track 0, and the drive is ready.
ST3655 Family AT Drives Product Manual, Rev. A 11
1.12 Agency listings
This drive is listed by agencies as follows:
• Recognized in accordance with UL 478 and UL 1950
• Certified to CSA C22.2 No. 220-M1986 and CSA C22.2 No. 950
• Certified to VDE 0805/05.90 and EN 60950/1.88 as tested by VDE
1.13 FCC verification
ST3655 family AT interface drives are intended to be contained solely
within a personal computer or similar enclosure (not attached to an
external device). As such, a drive is considered to be a subassembly
even when individually marketed to the customer. As a subassembly, no
Federal Communications Commission authorization, verification or certification of the device is required.
Seagate Technology, Inc. has tested these drives in an enclosure 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 of 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 equipment into a different outlet so that the receiver and
computer are on different branch outlets.
12 ST3655 Family AT Drives Product Manual, Rev. A
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, US
Government Printing Office, Washington, DC 20402. Refer to publication
number 004-000-00345-4.
Note. This digital apparatus does not exceed the Class B limits for radio
noise emissions from computer equipment as set out in the radio
interference regulations of the Canadian Department of communications.
Le présent appareil numérique n′émet pas de bruits radioélectriques dépassant les limites applicables aux appareils numériques
de Classe B prescrites dans le règlement sur le brouillage radioélectrique édicté par le Ministère des Communications du
Canada.
Sicherheitsanleitung
1. Das Gerrät ist ein Einbaugerät, das für eine maximale Umegebung-
stemperatur von 55°C vorgesehen ist.
2. Zur Befestigung des Laufwerks werden 3 Schrauben 6-32 UNC-2A
benötigt. Bei seitlicher Befestigung darf die maximale Länge der
Schrauben im Chassis nicht mehr als 3,3 mm und bei Befestigung an
der Unterseite nicht mehr als 5,08 mm betragen.
3. Als Versorgungsspannugen werden benötigt:
+5V ± 5% 0,5A
+12V ± 5% 0,5A (1,9A fur ca. 30 Sek. fur ± 10%)
4. Die Versorgungsspannung muβ SELV entsprechen.
5. Alle Arbeiten dürfen nur von ausgebildetem Servicepersonal durchge-
führt werden.
6. Der Einbaudes Drives muβ den Anforderungen gemäβ DIN IEC 950V
DC 0805/05.90 entsprechen.
ST3655 Family AT Drives Product Manual, Rev. A 13
2.0 Configuring and mounting the drive
This section contains the specifications and instructions for configuring
and mounting the drive.
2.1 Handling and static-discharge precautions
After you unpack the drive, and before you install it in a system, be careful
not to damage it through mishandling. Observe the following standard
handling and static-discharge precautions:
Caution:
• Keep the drive in its static-shielded bag until you are ready to complete
the installation. Do not attach any cables to the drive while it is in its
static-shielded bag.
• Before handling the drive, put on a grounded wrist strap, or ground
yourself frequently by touching the metal chassis of a computer that
is plugged into a grounded outlet. Wear a grounded wrist strap
throughout the entire installation procedure.
• Handle the drive by its edges or frame only.
• The drive is extremely fragile—handle it with care. Do not press down
on the drive top cover.
• Always rest the drive on a padded, antistatic surface until you mount
it in the computer.
• Do not touch the connector pins or the printed circuit board. Do not
touch the printed circuit cable between the circuit board and the
head/disc assembly.
• Avoid wool or synthetic clothing, carpeting, plastics, and Styrofoam;
these items cause static discharge.
• Do not remove the factory-installed labels from the drive or cover them
with additional labels. If you do, you void the warranty. Some factoryinstalled labels contain information needed to service the drive. Others
are used to seal out dirt and contamination.
0.70 ± 0.010
1.90
0.025
± 0.002
0.100 typ
0.230 ± 0.003
2.00
0.235 ± 0.025
0.160
0.070 ± 0.010
0.100 ± 0.010
0.025 ± 0.002
Pin 1
14 ST3655 Family AT Drives Product Manual, Rev. A
2.2 I/O cable and connector
The I/O connector is a 40-pin connector. The even pins are next to the
edge of the printed circuit board; the odd pins are away from the printed
circuit board. Pin 1 is near the 4-pin power connector. The I/O connector
is shown in Figure 2.
There is no pin 20 because that location is used as a key. Make sure the
corresponding pin hole on the cable connector is plugged to prevent the
connector from being installed upside down. The I/O cable cannot be
longer than 18 inches (0.46 meters).
The table below lists recommended parts for the mating connector. You
can use equivalent parts.
Part Description 3M part number
Connector 40-pin 3M-3417-7000
Connector 40-pin 3M-3448-2040
Flat cable AWG28 (stranded) 3M-3365-40
Figure 2. AT interface connector
ST3655 Family AT Drives Product Manual, Rev. A 15
2.3 Remote LED connection
To add an optional remote LED, attach a two-pin, 0.1-inch connector to
pins 13 and 14 of the options jumper block.
2.4 Jumpers
You can connect two drives to a daisy-chain cable if both drives meet
the same interface specifications. In a dual-drive configuration, one drive
is designated as the master (drive 0) and the other as the slave (drive 1).
See Figure 3 on page 16 for jumper settings.
If you intend to use either the cable select option or the spindle synchronization option in a dual-drive system, you should determine which of
these options your system supports before continuing. See your computer documentation for details. These options are described in more
detail in Sections 2.5 and 2.6.
2.4.1 Jumper sizes
The jumper blocks use 0.1-inch configuration jumpers. Use Seagate part
number 10562-001 or an equivalent.
Caution. If you try to install a jumper that is not the correct size, you
could damage the jumper and the jumper block pins.
2.4.2 Factory test jumper block (J6)
The pins on this jumper block are used for testing during the manufacturing process; do not install jumpers on them.
1
J6. Factory test
jumper block
2
3
4
pin 1
pin 1
J7. Optional mini
power connector
+5V
+12V
Ground
pin 1
111291078563
4
13
14
1
2
J8. Options jumper block
J1. Interface
connector
J5. Master/slave jumper block
341
2
Drive is master with
slave present
Drive is slave
One drive only
Cable select. You must
also install a jumper on
pins 6 and 8 of J8.
Spare
Note. All other pins are reserved.
Do not use them.
Remote LED
connection
External spindle synchro-
nization connection. Attach
a two-line cable here.
Spindle synchronization
through I/O pin 28
Cable select
Circuit
board
Circuit
board
Circuit
board
Circuit
board
+5V
+5V return
+12V return
+12V
16 ST3655 Family AT Drives Product Manual, Rev. A
Figure 3. Configuration jumpers
J3. Standard
power connector
ST3655 Family AT Drives Product Manual, Rev. A 17
2.4.3 Master/slave configuration
Your drive is shipped with a jumper installed in a spare location on pins 1
and 3 of the master/slave jumper block. If you are installing only one
drive, you can leave the jumper installed on pins 1 and 3, or you can
remove all jumpers from the jumper block.
You can install up to two drives in a standard AT system. If you are
installing two drives in your system, configure one drive as the master
and the other as the slave according to the following guidelines:
• To configure the drive as a master with a slave present, install a jumper
on pins 3 and 4 only of the master/slave jumper block of the master
drive.
Note. If both the master and the slave are ST3655 family drives, you
do not need to install a jumper on pins 3 and 4. This is because
the master can detect the presence of the slave using the
DASP– signal on the AT interface cable. If the drives in your
application do not implement the DASP– signal, install the
jumper on pins 3 and 4 of the master/slave jumper block on the
master drive only.
• To configure the drive as a slave, install a jumper on pins 1 and 2 only
of the master/slave jumper block on the slave drive.
With the aid of a special interface ribbon cable, the cable select option
allows you to determine the master and slave according to where the
drives are plugged in the cable. Cable select is described in more detail
in Section 2.5.
Note. Early ST3655 family drives do not support the cable select option.
To use cable select on an ST3550A, your circuit board part number
must be 260058-109 or 260100ST3390A or an ST3655A, your circuit board part number must be
260124-
xxx
.
xxx
. To use cable select on an
18 ST3655 Family AT Drives Product Manual, Rev. A
2.5 Cable select option
If your computer and both of your drives support cable select, you can
use the cable select option to determine the master and slave, according
to the following guidelines, which are illustrated in Figure 4.
• The drive plugged into the I/O connector that carries the CSEL signal
is the master.
• The drive plugged into the I/O connector that does not carry the CSEL
signal is the slave.
To configure your drives using cable select, you need to:
• Install jumpers on pins 1 and 2 and pins 3 and 4 of the master/slave
jumper block and pins 6 and 8 of the options jumper block. These
jumper blocks are both shown in Figure 3 on page 16.
• Use a special interface ribbon cable to select master and slave. The
cable and its connectors transmit the CSEL signal (pin 28) to the
master drive, but not to the slave drive, as shown in Figure 4.
Note. You cannot configure the drive for both cable select and spindle
synchronization at the same time because both options use the
same interface signal line (pin 28) and the same jumper block pin
(pin 8 of the options jumper block).
Master
Slave
Pin 28 is open
C
S
E
L
–
s
i
g
n
a
l
l
i
n
e
C
S
E
L
–
s
i
g
n
a
l
l
i
n
e
Master
Slave
Computer Computer
Pin 28 is open
ST3655 Family AT Drives Product Manual, Rev. A 19
Figure 4. Connecting cable-selected drives
Note. Early ST3655 family drives do not support the cable select option.
To use cable select on an ST3550A, your circuit board part number
must be 260058-109 or 260100ST3390A or an ST3655A, your circuit board part number must be
260124-
xxx
.
xxx
. To use cable select on an
20 ST3655 Family AT Drives Product Manual, Rev. A
2.6 Spindle synchronization option
If your computer and all of your drives support the spindle synchronization option, you can use the spindle synchronization to synchronize up
to 12 drive spindles to the spindle clock signal (SPSYNC–).
Note. You cannot configure the drive for both spindle synchronization
and cable select at the same time because both options use the
same interface signal line (pin 28) and the same jumper block pin
(pin 8 of the options jumper block). If you are using cable select,
skip this section.
When two or more drives are connected to the computer, the drives
automatically configure themselves for spindle synchronization in either
of two ways:
• The spindle synchronization clock signal is generated by the computer. The drives configure themselves as slaves and synchronize
their spindles according to the computer signal.
• The spindle synchronization clock signal is generated by one of the
drives. The master configures itself as the originator of the SPSYNC–
signal; the other drives become slaves, or receivers, of the SPSYNC–
signal.
The slave receives the signal to synchronize its spindle with the computer
or master and synchronizes its index with the SPSYNC– signal. Synchronization is achieved, and is indicated by the drive setting DRDY. (If a
drive that was already synchronized loses synchronization, but continues
to function, it does not clear DRDY.)
There are two ways to enable spindle synchronization:
• Enable pin 28 (SPSYNC–) of the AT interface connector by installing
a jumper on pins 8 and 10 of the options jumper block.
• Connect a twisted pair to pins 9 and 10 of the options jumper block to
transmit and receive SPSYNC–.
Use one strand of the twisted pair cable to connect pin 9 of the options
jumper block of each drive. Use the other strand to connect pin 10 of
the options jumper block of each drive. Use a 2-mm connector. The
cable should not be longer than six feet (1.8 meters). Figure 5 shows
you how to connect synchronized drives.
The spindle clock uses a single-ended TTL, active low, 75-Hz signal with
a clock period of 13.34 msec ± 0.5% and a duty cycle of 0.5 µsec
minimum, 500 µsec maximum. The spindle-clock leading edge to index
leading edge is 0 ± 250 µsec. Figure 6 shows the spindle-clock timing.
J8. Options jumper block
pin 9
pin 10
T1
Spindle clock
Internal index
T3
T2
ST3655 Family AT Drives Product Manual, Rev. A 21
Figure 5. Connecting synchronized drives
Figure 6. Spindle synchronization timing
T1 spindle clock period 13.34 msec ± 0.5%
T2 duty cycle
T3 spindle clock leading edge to
0.5 µsec minimum to
500 µsec maximum
0 µsec ± 250 µsec
index leading edge
22 ST3655 Family AT Drives Product Manual, Rev. A
2.7 Mounting the drive
You can mount the drive in any orientation. For optimum performance,
format the drive in the same orientation as you mount it in the computer.
Follow the guidelines below appropriate to the set of mounting holes you
elect to use: either bottom mounting holes or side mounting holes. Refer
to Figure 7 for the recommended mounting orientations. Refer to Figure 8 on page 24 for mounting dimensions.
Bottom mounting holes. Insert three 6-32 UNC screws in the three
available bottom mounting holes as shown in Figure 7.
Caution. Do not insert the bottom mounting screws more than
0.20 inches (6 turns) into the drive frame. If you use a screw
that is too long, you could damage the drive.
Side mounting holes. Use three 6-32 UNC screws in three of the six
available side mounting holes as shown in Figure 7. Use two mounting
holes on each side of the drive.
Caution. Do not insert the bottom mounting screws more than
0.13 inches (4 turns) into the drive frame. If you use a screw
that is too long, you could damage the drive.
ST3655 Family AT Drives Product Manual, Rev. A 23
Figure 7. Recommended mounting orientations
2.362 ± 0.010
(59.944 ± 0.254)
4.02 (102.11) max
5.77 (146.56) max
3.750 ± 0.010 (95.250 ± 0.254)
2.375 ± 0.020
(60.325 ± 0.508)
1.750 ± 0.010
(44.450 ± 0.254)
4.00 ± 0.02 (101.60
± 0.51)
0.63 ± 0.02 (16.00
± 0.51)
0.250 ± 0.010
(6.350 ± 0.254)
0.150 ± 0.010 (3.810
± 0.254)
0.030 ± 0.010 (0.762 ± 0.254)
1.00 (25.40) max
Six 6-32 UNC-2B threaded holes
Max screw insertion depth: 0.13 inch
Four 6-32 UNC-2B threaded holes
Max screw insertion depth: 0.20 inch
24 ST3655 Family AT Drives Product Manual, Rev. A
In the following figure, all dimensions are in inches (mm).
Figure 8. Mounting dimensions
ST3655 Family AT Drives Product Manual, Rev. A 25
3.0 AT interface
The AT interface implemented on these drives is compatible with the
requirements of the IBM AT bus. The AT interface consists of singleended, TTL-compatible receivers and drivers communicating through a
40-conductor flat-ribbon, nonshielded cable with a maximum length of
18 inches (0.46 meters) using an asynchronous interface protocol. The
drivers can sink up to 24 mA and drive a load up to 300 pF.
3.1 Command set
The following table lists all commands implemented on the ST3655 family
AT interface drives. For a complete description of all AT interface
commands, refer to the
publication number 36111tions:
FR Features register
SN Sector number register
DH Drive/head register
SC Sector count register
CY Cylinder register
n This register does not contain a valid parameter for this
command.
y This register contains a valid parameter for this command. In
the drive/head register, both the drive and head parameters are
valid for this command.
D The drive/head register contains a valid drive parameter for this
command. The head parameter is not valid for this command.
Seagate ATA Interface Reference Manual
xxx
. The table uses the following abbrevia-
,
Command name
Active and Set Idle Timer FB n y n n D
Active Immediate F9 n n n n D
Check Idle Mode FD n y n n D
Check Power Mode 98, E5 n y n n D
Execute Drive Diagnostics 90 n n n n D
continued
Command
code (in hex)
Parameters used
FR SC SN CY DH
26 ST3655 Family AT Drives Product Manual, Rev. A
continued from previous page
Command name
Format Track 50 n y n y y
Identify Drive EC n n n n D
Idle 97, E3 n y n n D
Idle and Set Idle Timer FA n y n n D
Idle Immediate 95, F8, E1 n n n n D
Initialize Drive Parameters 91 n y n n y
Read DMA C8, C9 — y y y y
Read Long 22, 23 n y y y y
Read Multiple C4 n y y y y
Read Sector 20, 21 n y y y y
Read Sector Buffer E4 n n n n D
Read Verify Sector 40, 41 n y y y y
Recalibrate 1X n n n n D
Seek 7X n n y y y
Set Features EF y n n n D
Set Multiple Mode C6 n y n n D
Sleep 99, E6 n n n n D
Standby 96, E2 n n n n D
Standby Immediate 94, E0 n n n n D
Write DMA CA, CB — y y y y
Write Long 32, 33 n y y y y
Write Multiple C5 n y y y y
Write Sector 30, 31 n y y y y
Write Sector Buffer E8 n n n n D
Command
code (in hex)
Parameters used
FR SC SN CY DH
ST3655 Family AT Drives Product Manual, Rev. A 27
3.1.1 Identify Drive command (ECH)
The sector buffer parameters for these drives are listed in the table below.
The
Seagate ATA Interface Reference Manual
36111-
xxx
, describes the Identify Drive command in detail.
Word Description Value
Configuration 347A
0
2000H Track offset option
1000
0400
0040
0020
0010
0008
0002
Default cylinders See page 1
1
Reserved 0
2
H
Data strobe offset option
H
Disc transfer rate
H
Fixed drive
H
Spindle motor control
H
Head switch time > 15 µsec
H
Not MFM encoded
H
Hard sectored
H
, publication number
available
available
> 10 Mbytes per second
option implemented
3
4
5
6
7–9
10–19
20
21
22
23–26
27–46
47
48
49
Default heads See page 1
Bytes per track 36540
Bytes per sector 580
Default sectors per track See page 1
Vendor-unique 0
Serial number Drive-unique
Buffer type 3
Buffer size/512 512
ECC bytes (R/W Long) 4
Firmware revision Drive-dependent
Model number Drive-dependent
Sectors per R/W
Multiple command
Double word I/O 0000
Capabilities 0901
8040
R/W Multiple supported;
H
64 sectors/block
H
IORDY, DMA supported
H
28 ST3655 Family AT Drives Product Manual, Rev. A
Word Description Value
50
51
52
53
54
55
56
57–58
59
60–61
62
63
64
65
66
67
68
69–
127
Reserved 0
PIO timing mode 0200
DMA timing mode 0200
Current valid 0003
H
H
, 54–58, 64–70 valid
H
Current cylinders Drive-unique
Current heads Drive-unique
Current sectors per track Drive-unique
Current sectors Drive-unique
Current multiple mode 0000
H
LBA total sectors 0
Single-word DMA 0000
No modes are active;
H
no modes are supported.
Multiword DMA 0103
Mode 0 is active; modes 0
H
and 1 are supported.
Advanced PIO 0001
Minimum multiword
180 nsec
Mode 3 is supported.
H
DMA transfer per word
Recommended
180 nsec
multiword DMA transfer
per word
Minimum PIO transfer
360 nsec
without IORDY
Minimum PIO transfer
180 nsec
with IORDY
Reserved 0
128–
159
Vendor-unique
x
ST3655 Family AT Drives Product Manual, Rev. A 29
Two commands that are described in the
ence Manual
require further elaboration. These commands are de-
Seagate ATA Interface Refer-
scribed below.
3.1.2 Set Features command (EFH)
The Set Features command is used to enable or disable the Read
Look-ahead, write immediate and write merging features. These features
are enabled during startup. The values used in the features register are
listed below:
02
Enable write immediate and write merging
H
55
82
AA
03
Disable cache
H
Disable write immediate and write merging
H
Enable cache
H
Set transfer mode
H
3.1.3 Sleep command (99H, E6H)
This command performs the same function as the Standby command.
3.2 AT Interface connector pin assignments
The signal name and signal direction for each I/O connector pin is
described in Figure 9 on page 30. See the
Reference Manual
, publication number 36111-
Seagate ATA Interface
xxx
, for a complete de-
scription of each pin.
Signal names are in upper case. If the signal name is followed by a minus
sign (–), the signal is active low. Otherwise, the signal is active high.
Drive 0
(master)
Drive 1
(slave)
28
34
39
28
34
39
SPSYNC–:CSEL
PDIAG
–
DASP–
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Host Reset
Ground
Host Data Bus Bit 7
Host Data Bus Bit 8
Host Data Bus Bit 6
Host Data Bus Bit 9
Host Data Bus Bit 5
Host Data Bus Bit 10
Host Data Bus Bit 4
Host Data Bus Bit 11
Host Data Bus Bit 3
Host Data Bus Bit 12
Host Data Bus Bit 2
Host Data Bus Bit 13
Host Data Bus Bit 1
Host Data Bus Bit 14
Host Data Bus Bit 0
Host Data Bus Bit 15
Ground
(No Pin)
DMA Request
Ground
Host I/O Write
Ground
Host I/O Read
Ground
I/O Channel Ready
Spindle sync
or Cable Select
DMA Acknowledge
Ground
Host Interrupt Request
Host 16 Bit I/O
Host Address Bus Bit 1
Passed Diagnostics
Host Address Bus Bit 0
Host Address Bus Bit 2
Host Chip Select 0
Host Chip Select 1
Drive Active/
Drive 1 Present
Ground
Host
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
*28
29
30
31
32
33
*34
35
36
37
38
*39
40
Drive
30 ST3655 Family AT Drives Product Manual, Rev. A
–
Reset
Ground
DD7
DD8
DD6
DD9
DD5
DD10
DD4
DD11
DD3
DD12
DD2
DD13
DD1
DD14
*
Drive-to-drive signals
Figure 9. AT interface connector pin assignments
DD0
DD15
Ground
(removed)
DMARQ
Ground
–
DIOW
Ground
–
DIOR
Ground
IORDY
SPSYNC–:CSEL
DMACK
IOCS16
Ground
INTRQ
DA1
PDIAG
DA0
DA2
CS1FX
CS3FX
DASP
Ground
–
–
–
–
–
–
Host
28
34
39
Address valid
DIOR− and DIOW−
Write data valid
Read data valid
IOCS16−
T7
T1
T2
T3
T5
T6
T4
T0
T9 T8
ST3655 Family AT Drives Product Manual, Rev. A 31
Appendix. Timing diagrams
Without IORDY, the drive operates at mode 3 programmed I/O timing
specifications, as shown below.
Figure 10. Programmed I/O timing without IORDY
Time Description Min Max
T0 Cycle time 360 nsec —
Drive address (CS1FX–, CS3FX–,
T1
30 nsec —
DA0, DA1 and DA2) valid and
DIOR–/DIOW– setup
T2 DIOW– or DIOR– pulse width 80 nsec —
T3 DIOW– data setup 30 nsec —
T4 DIOW– data hold 15 nsec —
T5 DIOR– data setup 20 nsec
T6 DIOR– data hold 5 nsec —
T7 DIOW– or DIOR– to address valid hold — 40 nsec
T8 DIOW– false to write data hold — 30 nsec
T9 DIOR– false to read data hold 10 nsec
Read data valid
IOCS16−
T1
T0
T2
T4
T6
T7
T9
T8
T11
T10
T3
IORDY
T5
32 ST3655 Family AT Drives Product Manual, Rev. A
When using IORDY, the drive operates at mode 3 programmed I/O timing
specifications, as shown below.
Address valid
DIOR− or DIOW−
Write data valid
Figure 11. Programmed I/O timing with IORDY
Time Description Min Max
T0 Cycle time 180 nsec —
T1 Address valid until IOCS16– is asserted — 40 nsec
Drive address (CS1FX–, CS3FX–,
T2
30 nsec —
DA0, DA1 and DA2) valid before DIOR–
or DIOW– setup
T3 IORDY setup time — —
DIOW– or DIOR– pulse width (8-bit) 80 nsec —
T4
DIOW– or DIOR– pulse width (16-bit) 80 nsec —
T5 IORDY pulse width — —
T6 DIOW– data setup 30 nsec —
T7 DIOR– data setup 20 nsec —
T8 DIOR– data hold 5 nsec —
T9 DIOW– data hold 15 nsec —
T10 DIOW– or DIOR– to address valid hold 10 nsec —
T11 Address valid until IOCS16– is negated — 30 nsec
DMACK−
DMARQ
T0
DIOR− or DIOW−
Read data valid
Write data valid
TK
TG
TDTI TJ
TH
TF
TL
TE
ST3655 Family AT Drives Product Manual, Rev. A 33
The drive operates at mode 1 multiword DMA timing specifications, as
shown below.
Figure 12. Multiword DMA timing
Time Description Min Max
T0 Cycle time 180 nsec —
TD DIOW– or DIOR– pulse width (16-bit) 80 nsec —
TE DIOR– data access — 60 nsec
TF DIOW– data hold 5 nsec —
TG DIOR– data setup 30 nsec —
TH DIOW– data hold 15 nsec —
TI DMACK– to DIOR– or DIOW– setup 0 nsec —
TJ DIOR– or DIOW– to DMACK– hold 5 nsec —
TK
DIOR– negated pulse width 60 nsec —
R
TK
DIOW– negated pulse width 60 nsec —
W
DIOR– to DMARQ delay — 120 nsec
TL
R
TL
DIOW– to DMARQ delay — 40 nsec
W
Seagate Technology, Inc.
920 Disc Drive, Scotts Valley, California 95066, USA
Publication Number: 36244-003, Rev. A, Printed in Thailand
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