seagate ST9100A User manual

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ST9100A

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AT Interface Drive

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Product Manual

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ST9100A

AT Interface Drive

Product Manual

36211-001, Rev. A

27 April 1993

© 1993 Seagate Technology, Inc. All rights reserved
Publication Number: 36211-001, Rev. A

®

Seagate

, Seagate Technology®, and the Seagate logo are registered
trademarks of Seagate Technology, Inc. Other product names are reg­istered trademarks or 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.

ST9100A Product Manual, Rev. A iii

Contents

1.0 Specification summary . . . . . . . . . . . . . . . . . . . . 1

1.1 Formatted capacity . . . . . . . . . . . . . . . . . . . . . 1

1.2 Physical organizat ion . . . . . . . . . . . . . . . . . . . . 1

1.3 Logical organization . . . . . . . . . . . . . . . . . . . . . 1

1.4 Default logical geometry . . . . . . . . . . . . . . . . . . . 1

1.5 Functional specifications . . . . . . . . . . . . . . . . . . 2

1.6 Physical dimens ions . . . . . . . . . . . . . . . . . . . . 2

1.7 Seek time . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.8 Spinup times (typical) . . . . . . . . . . . . . . . . . . . . 3

1.9 Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.10 Environment . . . . . . . . . . . . . . . . . . . . . . . . 3

1.10.1 Acoustics . . . . . . . . . . . . . . . . . . . . . . . 3

1.10.2 Ambient temperature . . . . . . . . . . . . . . . . . 3

1.10.3 Temperature gradient . . . . . . . . . . . . . . . . . 3

1.10.4 Relative humidity . . . . . . . . . . . . . . . . . . . 4

1.10.5 Altitude . . . . . . . . . . . . . . . . . . . . . . . . 4

1.10.6 Shock . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.10.7 Vibration . . . . . . . . . . . . . . . . . . . . . . . . 4

1.11 Power specifications . . . . . . . . . . . . . . . . . . . . 5

1.11.1 Power management modes . . . . . . . . . . . . . . 5

1.11.2 Power consumption . . . . . . . . . . . . . . . . . . 7

1.11.3 Typical current profiles . . . . . . . . . . . . . . . . 7

1.11.4 Input power noise . . . . . . . . . . . . . . . . . . . 7

1.12 UL/CSA listing . . . . . . . . . . . . . . . . . . . . . . . 8

1.13 FCC verification . . . . . . . . . . . . . . . . . . . . . . 8

2.0 Drive handling and mounting . . . . . . . . . . . . . . . . 11

2.1 Handling and static-discharge precautions . . . . . . . . . 11

iv ST9100A Product Manual, Rev. A

2.2 Mounting the ST9100A . . . . . . . . . . . . . . . . . . 11

3.0 AT interface . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.1 Drive configuration . . . . . . . . . . . . . . . . . . . . . 13

3.1.1 Master/slave selection . . . . . . . . . . . . . . . . 13

3.1.2 Remote LED . . . . . . . . . . . . . . . . . . . . . 13

3.2 Onboard drive diagnostics . . . . . . . . . . . . . . . . . 15

3.3 AT bus signal levels . . . . . . . . . . . . . . . . . . . . 15

3.4 AT interface connector . . . . . . . . . . . . . . . . . . . 15

3.5 AT interface cable . . . . . . . . . . . . . . . . . . . . . 16

3.6 AT interface connector pin assignments . . . . . . . . . . 17

3.7 AT interface commands for the ST9100A . . . . . . . . . 18

3.7.1 Standby Immediate (E0

3.7.2 Idle Immediate (E1

3.7.3 Standby (E2

3.7.4 Idle (E3

/ 96H) . . . . . . . . . . . . . . . . . . 20

H

/ 97H) . . . . . . . . . . . . . . . . . . . . 22

H

3.7.5 Check Power Mode (E5

3.7.6 Set Sleep Mode (E6

3.7.7 Identify Drive (EC

3.7.8 Set Features (EF

H

H

3.7.9 Active Immediate (F9

3.7.10 Idle and Set Idle Timer (FA

3.7.11 Active and Set Idle Timer (FB

3.7.12 Check Idle Mode (FD

/ 94H) . . . . . . . . . . . . 18

H

/ 95H / F8H) . . . . . . . . . . . 19

H

/ 98H) . . . . . . . . . . . 23

H

/ 99H) . . . . . . . . . . . . . 24

H

) . . . . . . . . . . . . . . . . . . 25

) . . . . . . . . . . . . . . . . . . 27

) . . . . . . . . . . . . . . . . 28

H

) . . . . . . . . . . . . 29

H

) . . . . . . . . . . . 30

H

) . . . . . . . . . . . . . . . 31

H

3.7.13 Rest/Resume commands . . . . . . . . . . . . . . 32

ST9100A Product Manual, Rev. A v

Figures

Figure 1. Startup and operation current profile for the ST9100A . . 8

Figure 2. ST9100A mounting dimensions . . . . . . . . . . . . . . 12

Figure 3. ST9100A connector setup . . . . . . . . . . . . . . . . 14

Figure 4. AT interface connector dimensions . . . . . . . . . . . . 16

ST9100A Product Manual, Rev. A 1

1.0 Specification summary

1.1 Formatted capacity

Guaranteed Mbytes 85.8
Guaranteed sectors 167,552
Bytes per sector 512

1.2 Physical organization

Read/Write heads 2
Discs 1

1.3 Logical organization

Sectors per track (max) 64
Read/Write heads (max) 16
Cylinders (max) Unrestricted

Note. All head, cylinder, and sector geometries are supported subject

to the maximums specified and to the following condition:

sectors

(

) ×

(heads) × (cylinders) ≤ total sectors per drive

1.4 Default logical geometry

Sectors per track 16
Read/Write heads 14
Cylinders 748

2 ST9100A Product Manual, Rev. A

1.5 Functional specifications

Interface AT
Recording method RLL (1,7)
Recording density (BPI) 58,200
Flux density (FCI) 43,760
Track density (TPI) 2,650
Spindle speed (RPM)
Internal data transfer rate up to 22.4 Mbits/sec (6 zones)—ZBR
I/O data transfer rate up to 4 Mbytes/sec
Interleave 1:1
Buffer 120 Kbytes

3,545 ± 0.5%

1.6 Physical dimensions

Height (max) 0.504 inches (12.80 mm)
Width (max) 2.760 inches (70.10 mm)
Depth (max) 4.001 inches (101.85 mm)
Weight (max) 4.8 oz (0.136 Kg)

1.7 Seek time

Seek time is a true statistical average (at least 5,000 measurements) of
seek time, less controller overhead. All measurements are made with
nominal power at sea level and 25°C ambient temperature. Track-to­track seek time is an average of all possible single-track seeks in both
directions. Average seek time is measured by executing seek commands
between random sector addresses. Full-stroke seek time is one-half the
time needed to seek from the first data sector to the maximum data sector
and back to the first sector. Host overhead varies between systems and
cannot be specified.

Track-to-track

typical avg. (msec)
maximum avg. (msec)

5
7

ST9100A Product Manual, Rev. A 3

Average

typical avg. (msec)
maximum avg. (msec)

Full-stroke

typical avg. (msec)
maximum avg. (msec)

Average latency (msec) 8.46

16
19

26
28

1.8 Spinup times (typical)

Spinup time from Power-on to Ready is 10 seconds (typical).
Spinup time from Standby to Ready is 3 seconds (typical).

1.9 Reliability

Nonrecoverable read errors 1 per 1013 bits read
Mean time between failures 300,000 power-on hours

(nominal power, at sea level,

25°C ambient temperature)
Preventative maintenance None required
Mean time to repair 10 minutes
Service life 5 years

1.10 Environment

1.10.1 Acoustics

30 dBA maximum (sound pressure) in Idle mode, at 1 meter.

1.10.2 Ambient temperature

Operating 5° to 55°C (41° to 131°F)
Nonoperating –40° to 70°C (–40° to 158°F)

1.10.3 Temperature gradient

Operating 30°C/hr max (54°F/hr), without condensation
Nonoperating 30°C/hr max (54°F/hr), without condensation

4 ST9100A Product Manual, Rev. A

1.10.4 Relative humidity

Operating 8% to 80% noncondensing;

Max. wet bulb temperature: 40°C (78.8°F)

Nonoperating 8% to 90% noncondensing

Max. wet bulb temperature: 56°C (132°F)

1.10.5 Altitude

Operating –1,000 ft to 10,000 ft (–304.8 m to 3,048 m)
Nonoperating –1,000 ft to 40,000 ft (–304.8 m to 12,192 m)

1.10.6 Shock

All shock specifications assume that the drive is mounted in an approved
orientation with the shock input levels measured at the drive mounting
screws. The nonoperating specifications assume that the read/write
heads are positioned in the shipping zone.

Note. At power-down and during Idle and Standby modes, the read/write

heads automatically move to the shipping zone. The head and
slider assembly park inside of the maximum data cylinder. When
power is applied, the heads recalibrate to track 0.

1.10.6.1 Operating shock

The maximum shock the ST9100A can experience during operation
without incurring nonrecoverable data errors is 10 Gs (based on half
sine-wave shock pulses of 11 msec).

1.10.6.2 Nonoperating shock

The maximum shock the ST9100A can experience without incurring drive
damage or degradation in performance when the drive is subsequent ly
put into operation is 150 Gs (based on half-sine shock pulses of 11
msec).

1.10.7 Vibration

All vibration specifications assume that the drive is mounted in an
approved orientation with the vibration input levels measured at the drive
mounting screws. The nonoperating specifications assume that the
read/write heads are positioned in the shipping zone.

ST9100A Product Manual, Rev. A 5

1.10.7.1 Operating vibration

Maximum vibration without drive damage or degradation in performance:

5–22 Hz 0.020-inch displacement (double amplitude)
22–500 Hz 0.5 G acceleration (peak)
500–22 Hz 0.5 G acceleration (peak)
22–5 Hz 0.020-inch displacement (double amplitude)

1.10.7.2 Nonoperating vibration

Maximum vibration without causing physical damage or degradation in
performance when the device is subsequently put into operation:

5–22 Hz 0.162-inch displacement (double amplitude)
22–500 Hz 4 Gs acceleration (peak)
500–22 Hz 4 Gs acceleration (peak)
22–5 Hz 0.162-inch displacement (double amplitude)

1.11 Power specifications

The ST9100A receives DC power (+5V), through pin 41 and pin 42 of
the AT interface connector; pin 43 is ground.

1.11.1 Power management modes

Power management is required for low-power, portable computer sys­tems. In most systems, you can control power management through the
system setup program. The ST9100A features several power manage­ment modes, which are described briefly below:

Active mode. The drive is in Active mode during the read/write and seek
operations.

Idle-Ready mode. In Idle-Ready mode, the spindle is up to speed and
the heads are on track at the last sector accessed. The drive accepts all
commands, and returns to Active mode when disc access is necessary.

Idle mode. At power-on, the drive sets the idle timer to enter Idle mode
after 5 seconds of inactivity. You can set the idle timer delay using the
system setup utility. In Idle mode, the spindle remains up to speed. The
heads are parked and latched away from the data zones for maximum

6 ST9100A Product Manual, Rev. A

data safety. 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. The drive can also enter Standby mode
after a specifiable length of time has elapsed with the drive in Idle mode.
The standby timer delay is system dependent, and is usually established
using the system setup utility. In Standby mode, the buffer remains
enabled, 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 when a Sleep Immediate
command has been received from the host. The heads are parked and
the spindle is at rest. The drive leaves Sleep mode when a Hard Reset
or Soft Reset command is sent from the host. After a soft reset has been
received, the drive exits Sleep mode and enters Standby mode with all
current emulation and translation parameters intact.

Rest mode. Some host systems reduce drive power consumption by
removing all power from the drive, using a state known as Rest mode.
In entering Rest mode, the host saves drive state information (including
current logical geometry, set feature parameters, cache status and task
file registers) prior to powering down the drive, then restores the drive to
its prerest condition once power is restored. Rest mode is implemented
using three commands: Rest, Read Drive State, and Restore Drive State.
The Rest command prepares the drive for a subsequent Read Drive
State command. The Read Drive State command captures the state of
the I/O registers and transfers this data to nonvolatile memory within the
host. The Restore Drive State command reads the drive state data from
memory and restores the drive state based on these data.

Idle and standby timers. The drive sets default time delays for both the
idle timer and the standby timer at power-on. In most systems, you can
set these delays using the system setup utility. Each time the drive
performs an Active function (read, write or seek), the idle timer is
reinitialized, and begins the countdown from the specified delay time to
zero. If the idle timer reaches zero before any drive activity is required,
the drive makes a transition to Idle mode. After making the transition to
Idle mode, the drive begins the standby timer countdown. 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.

ST9100A Product Manual, Rev. A 7

1.11.2 Power consumption

Power requirements for the ST9100A are listed below. All typical meas­urements are taken at 5V and zero ripple on a 10 MHz AT system.
Maximums are measured at 5.25V.

Typical Active mode current and power specifications assume nominal
voltages applied, 25°C ambient temperature at sea level, with the spindle
rotating (two spindle rotations between each operation) and the drive in
default logical geometry. Maximum seek currents and power usage are
measured on repetitive one-third-stroke buffered seeks with one-half
spindle rotation between each seek. Maximum read/write currents and
power are measured with one-half spindle rotation between each opera­tion. Transient state changes may cause current peaks above the
maximum levels.

Watts RMS

Drive / Mode

Spinup 3.5 4.8 0.9
Active:

Seeking

Read/Write
Idle mode 0.54 0.66 0.12
Standby mode 0.12 0.18 0.027
Sleep mode 0.06 0.11 0.020

(Typical)

1.55

1.45

Watts RMS
(Maximum)

1.65

1.6

Amps RMS
(Maximum)

0.32

0.30

1.11.3 Typical current profiles

A typical startup and operation current profile for the ST9100A is shown
in Figure 1 on page 8.

1.11.4 Input power noise

Voltage tolerance (including ripple): + 10% – 8%
Maximum permitted input noise ripple is 150 mV (peak-to-peak).
Maximum permitted input noise is 10 MHz.

Active mode

Spinup

Upload

code

Idle

mode

Standby

mode

Ready

Time (seconds)

100

200

300

400

0

1 2

3 4 5

6

7

8 9

10

500

Current

(mA)

8 ST9100A Product Manual, Rev. A

Figure 1. Startup and operation current profile for the ST9100A

1.12 UL/CSA listing

The ST9100A is listed in accordance with UL 1950 and CSA C22.2
(950-M89), and meets all applicable sections of IEC 380, IEC 435,
IEC 950, VDE 0806/08.81 and EN 60950 as tested by TUV-Rheinland,
North America.

1.13 FCC verification

The ST9100A is intended to be contained solely within a personal
computer or similar enclosure (not attached to an external device). As
such, the 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

ST9100A Product Manual, Rev. A 9

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.

.

ST9100A Product Manual, Rev. A 11

2.0 Drive handling and mounting

2.1 Handling and static-discharge precautions

After unpacking, and prior to system integration, the drive may be
exposed to potential handling and ESD hazards. It is mandatory that you
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. Always rest
the drive on a padded antistatic surface until you mount it in the host
system.

2.2 Mounting the ST9100A

You can mount the ST9100A in any orientation, as long as the drive is
securely fastened to a rigid frame using four side-mounting screws or
four bottom-mounting screws. Allow a minimum clearance of 0.030
inches (0.762 mm) around the entire perimeter of the drive for cooling
airflow.

Figure 2 on page 12 provides mounting dimensions for the ST9100A.
These drives are designed in accordance with industry-standard MCC
direct-mounting specifications, and require the use of MCC-compatible
connectors in fixed-mounting applications.

Caution. To avoid damaging the drive:

metric

• Use M3X0.5

• Do not insert mounting screws more than 0.150 inches (3.81 mm) into

the mounting holes.

not

• Do

overtighten the screws (maximum torque: 3 inch-lb).

mounting screws

only

.

4X 3 mm × 0.5 mm,

0.15 in (3.81mm)
min. full thread

0.000

2.430 ± 0.010
(61.72 ± 0.25)

0.000

1.227 ± 0.025
(31.17 ± 0.61)

3.986 ± 0.015

(101.24 ± 0.38)

1.500 ± 0.010
(38.10 ± 0.25)

4X 3 mm × 0.5 mm,

0.15 in (3.81 mm)

min. full thread

0.079 (2.00)

Pin 1

Pin 20 removed
for keying

0.079 (2.00)

2.740 ± 0.020

(69.60 ± 0.51)

1.375 ± 0.015

(34.93 ± 0.38)

0.000 in (mm)

0.489 ± 0.015
(12.42 ± 0.38)

0.155 ± 0.020
(3.94 ± 0.51)

0.039 ± 0.020
(0.99 ± 0.51)

0.118 ± 0.010
(3.00 ± 0.25)

0.157 ± 0.015
(3.99 ± 0.38)

0.239 ± 0.035
(6.07 ± 0.89)

Dimensions are in inches (mm)

0.152 ± 0.005
(3.86 ± 0.12)

12 ST9100A Product Manual, Rev. A

Figure 2. ST9100A mounting dimensions

ST9100A Product Manual, Rev. A 13

3.0 AT interface

The ST9100A uses the industry-standard ATA task file interface. The
drives support both 8-bit and 16-bit data transfer and have no DMA
capability. All data transfers are completed through programmed I/O. Up
to two drives can be daisy-chained (as master and slave) on the same
host bus.

3.1 Drive configuration

3.1.1 Master/slave selection

A master/slave relationship must be established between drives on the
AT bus. Drive 1 is configured as the master and Drive 2 is configured as
the slave. Refer to the table below and Figure 3 on page 14 for jumper
settings used to configure the drive as a master or a slave.

Jumper
for pins
A and B

Removed Removed Drive is master; no slave drive present
Removed Installed Drive is master; Seagate slave drive present
Installed Removed Drive is slave; Seagate master drive present
Installed Installed Reserved configuration (do not use)

Jumper
for pins
C and D Configuration

3.1.2 Remote LED

The drive indicates activity to the host through the DASP– line (pin 39)
on the AT interface. This line can be connected to a drive status indicator
driving an LED at 5V. The line has a 30 mA nominal current limit.

Master/slave

configuration jumpers

Pin 1

Pin 20 removed

for keying

Circuit board

B D
A C

Drive is master; no slave drive present
Drive is master; Seagate slave drive present
Drive is slave; Seagate master drive present
Reserved position (Do not use)

14 ST9100A Product Manual, Rev. A

Figure 3. ST9100A connector setup

ST9100A Product Manual, Rev. A 15

3.2 Onboard drive diagnostics

At power-on, the drive executes a series of diagnostic tests. A series of
LED flashes on the system panel indicate a failure.

Error codes

(LED Flashes) Error type

1 Microprocessor error
2 ROM checksum error
3 AT interface chip failure
5 External RAM error
6 Buffer RAM error

3.3 AT bus signal levels

Signals driven by the drive must have the following output characteristics
at the drive connector:

Logic Low 0.0V to 0.4V
Logic High 2.5V to 5.25V

Signals received by the drive must have the following input charac­teristics, measured at the drive connector:

Logic Low 0.0V to 0.8V
Logic High 2.0V to 5.25V

3.4 AT interface connector

The drive connector is a 44-conductor connector with 2 rows of 22 male
pins on 0.079 inch (2 mm) centers (see Figure 4 on page 16).

The mating-cable connector is a 44-conductor nonshielded connector
with 2 rows of 22 female contacts on 0.079 inch (2 mm) centers. It is
recommended that the connectors be keyed by inserting a plug into the
pin 20 location of each interface connector. Strain relief is recommended.

Use MCC-compatible connectors, such as Molex part number 87368-

x

, for fixed-mounting applications. For applications involving flexible

442
cables or printed circuit cables (PCCs), use Molex part number 87259­4413 or equivalent to connect the system to the drive. Select a connector
that provides adequate clearance for the master/slave configuration

Do not scale

1.654

0.158 ± 0.003

0.152 ± 0.005

0.079 ± 0.003

0.020 ± 0.002
sq. typ.

0.079 ± 0.003

drive circuit board

44 signal/power pins

(22 rows)

Configuration jumpers

(2 rows)

Note. Tolerances are noncumulative over entire range

16 ST9100A Product Manual, Rev. A

jumpers (if the application requires the use of such jumpers). See Figure
4 for details.

3.5 AT interface cable

Maximum cable length is 18 inches (457 mm). It is recommended that
the connectors be keyed by the use of a plug in the pin 20 location of
each interface connector.

Figure 4. AT interface connector dimensions

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
41
42
43
44

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)
Reserved
Ground
Host I/O Write
Ground
Host I/O Read
Ground
Reserved
Reserved
Reserved
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 / Slave Present
Ground
+5V (logic)
+5V (motor)
Ground for power pins
Reserved

Host pin # and signal description

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
41
42
43
44

Drive pin #

Signal name

ST9100A Product Manual, Rev. A 17

3.6 AT interface connector pin assignments

The following diagram summarizes the signal pin assignments for the
ST9100A AT interface connector.

–

Reset

Ground

DD7
DD8
DD6
DD9
DD5

DD10

DD4

DD11

DD3

DD12

DD2

DD13

DD1

DD14

DD0

DD15

Ground

(removed)

Reserved

Ground

–

DIOW
Ground

–

DIOR

Ground
Reserved
Reserved
Reserved

Ground

INTRQ

IOCS16

DA1

–

PDIAG

DA0

DA2
CS1FX
CS3FX

–

DASP
Ground

Power
Power

Ground

Reserved

–

–
–

18 ST9100A Product Manual, Rev. A

3.7 AT interface commands for the ST9100A

The following commands are specific to the ST9100A. For a description
of any AT interface commands not found in this manual and Seagate’s
implementation of the AT interface, refer to the

Specification

, publication number 36111-001.

Seagate ATA Interface

For maximum compatibility, there may be more than one opcode for
some commands. In such instances, all opcodes perform in an equivalent
manner and are treated identically by the drive.

In all of the following tables, D/S designates the drive select bit and an “X”
designates that the register is not used for the particular command.
Notations for special register functions are listed in the command table
and explained in the command descriptions.

3.7.1 Standby Immediate (E0H / 94H)

When the drive receives this command, it enters Standby mode imme­diately. The drive sets BSY, initiates a shutdown sequence, enters
Standby mode, clears BSY, and generates an interrupt. If the drive is
already in Standby mode when this command is received, it sets BSY,
clears BSY and generates an interrupt.

E0

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 0 0 0 0 0

X

X

1 0 1 D/S X

X

X

ST9100A Product Manual, Rev. A 19

94

Command

(1F7

Cyl. High

(1F5

Cyl. Low

(1F4

Drv. Head

(1F6

Sec. Num.

(1F3

Sec. Cnt.

(1F2

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

H

1 0 0 1 0 1 0 0

)

H

)

H

)

H

1 0 1 D/S X

)

H

)

H

)

H

X

X

X

X

3.7.2 Idle Immediate (E1H / 95H / F8H)

When the drive receives this command, it sets BSY and enters Idle mode.
If the drive is in Standby mode, the spinup routine is executed. If the drive
is in either Active or Idle mode, the spindle is already up to speed, and
the spinup routine is skipped. Next, the drive clears BSY and generates
an interrupt.

E1

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 0 0 0 0 1

X

X

1 0 1 D/S X

X

X

20 ST9100A Product Manual, Rev. A

95

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

F8

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 0 0 1 0 1 0 1

X

X

1 0 1 D/S X

X

X

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 1 1 0 0 0

X

X

Drv. Head

(1F6

H

Sec. Num.

(1F3

H

Sec. Cnt.

(1F2

H

1 0 1 D/S X

)

)

)

X

X

3.7.3 Standby (E2H / 96H)

When the drive receives this command, it sets BSY and makes a
transition to Standby mode. Depending on the value placed in the Sector
Count register, the drive either enables or disables the standby
timer. The drive then clears BSY and generates an interrupt. Placing a
zero value in the Sector Count register disables automatic Standby.
Placing a nonzero value in the Sector Count register enables the standby
timer to count down in 5-second increments. A value of 12 sets the

ST9100A Product Manual, Rev. A 21

standby timer for sixty seconds before the Standby routine is initiated. A
value of 13 sets the timer for sixty-five seconds. The minimum amount
of time allowed for the standby timer is sixty seconds. Consequently, all
values from 1−11 have an equivalent effect to a value of 12 for the
standby timer. The delay timer is reinitialized by the drive whenever the
drive enters Active mode. If the drive is already in Standby mode, this
command has no effect. The default power-on condition for this drive has
automatic power-down disabled.

E2

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

96

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 0 0 0 1 0

X

X

1 0 1 D/S X

X

standby timer delay (in 5-second increments)

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 0 0 1 0 1 1 0

X

X

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

1 0 1 D/S X

X

standby timer delay (in 5-second increments)

22 ST9100A Product Manual, Rev. A

3.7.4 Idle (E3H / 97H)

When the drive receives this command, it sets BSY, makes a transition
to Idle mode, sets the standby timer if necessary, clears BSY and
generates an interrupt. The minimum amount of time allowed for the idle
timer is sixty seconds. Consequently, all values from 1 to 11 have an
equivalent effect to a value of 12 for the standby timer.

E3

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

97

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 0 0 0 1 1

X

X

1 0 1 D/S X

X

standby timer delay (in 5-second increments)

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 0 0 1 0 1 1 1

X

X

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

1 0 1 D/S X

X

idle timer delay (in 5-second increments)

ST9100A Product Manual, Rev. A 23

3.7.5 Check Power Mode (E5H / 98H)

This command returns a code for the power mode the drive is currently
in or making a transition to. When the drive receives this command, it
sets BSY, returns a value representing the current mode through the
Sector Count register, clears BSY and generates an interrupt.

The return values are as follows:

= The drive is in, or entering, Standby mode.

00

H

= The drive is in, or entering, either Idle or Active mode.

FF

H

E5

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

98

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 0 0 1 0 1

X

X

1 0 1 D/S X

X

X

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 0 0 1 1 0 0 0

X

X

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

1 0 1 D/S X

X

X

24 ST9100A Product Manual, Rev. A

3.7.6 Set Sleep Mode (E6H / 99H)

This command tells the drive to enter Sleep mode immediately. When the
drive receives this command, it sets BSY, enters Sleep mode, clears BSY
and generates an interrupt. When a soft reset is sent from the host, the drive
leaves Sleep mode and makes a transition to Standby mode. After a soft
reset has been received, the drive exits Sleep mode and enters Standby
mode with all emulation and translation parameters intact. After a hard reset
has been received, the drive returns to Active mode.

E6

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

98

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 0 0 1 1 0

X

X

1 0 1 D/S X

X

X

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 0 0 1 1 0 0 0

X

X

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

1 0 1 D/S X

X

X

ST9100A Product Manual, Rev. A 25

3.7.7 Identify Drive (ECH)

The drive sends this command to system ROM during the system startup
process. ROM clears the BUSY status within 100 nsec from power-on,
but does not indicate the DRIVE READY status until after the upload of
external RAM is complete. This command can be executed before the
DRIVE READY status has been asserted.

EC

Command

(1F7

Cyl. High

(1F5

Cyl. Low

(1F4

Drv. Head

(1F6

Sec. Num.

(1F3

Sec. Cnt.

(1F2

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

H

1 1 1 0 1 1 0 0

)

H

)

H

)

H

1 0 1 D/S X

)

H

)

H

)

H

X

X

X

X

The Identify Drive command causes 512 bytes (256 words) of informa­tion to be returned to the host. When the drive receives this command,
it sets BSY, stores the information in the sector buffer, sets DRQ, and
generates an interrupt.

26 ST9100A Product Manual, Rev. A

The following table summarizes the information transferred through the

x

Identify Drive command. Parameters listed with an “

” are variable. See

Section 1 of this manual for default parameter settings for the ST9100A.

Word Description Value

Configuration information:
Bit 10: disc transfer ≤ 10 Mbits/sec
Bit 6: fixed drive

0

Bit 4: head switch time > 15 µsec

045A

H

Bit 3: not MFM encoded
Bit 1: hard sectored disc

Number of fixed cylinders

1

(default logical emulation): 748

02EC

H

2 Reserved 0000
3 Number of heads (default): 14 000E
4 Number of unformatted bytes per track: 36,240 8D90
5 Number of unformatted bytes per sector: 584 0248

Number of sectors per track

6

(default logical emulation): 16

0010

7–9 Reserved 0000

10–19

20

Serial Number:
(20 ASCII characters, 0000

= none)

H

Controller type = dual-ported multisector buffer
with caching

ASCII

0003

21 Buffer size (120 Kbytes) 00F0
22 Number of ECC bytes 0010

23–26

27–46

Firmware revision (8 ASCII character string):

xx

= ROM ver., ss = RAM ver., tt = RAM ver.

Drive model number:
(40 ASCII characters, padded to end of string)

xx.ss.tt

ST9

47 Read Multiple command supported 0000

H
H
H
H

H

H

H

H
H

xxx

H

48 Cannot perform double word I/O 0000
49 Capabilities: DMA not supported 0000
50 Reserved 0000

H
H
H

ST9100A Product Manual, Rev. A 27

Word Description Value

51 Minimum PIO data transfer cycle time 0000
52

Minimum DMA transfer cycle time

(not supported)
53 The fields in translation mode may be valid 0001
54 Number of cylinders (current emulation mode)
55 Number of heads (current emulation mode)

56

Number of sectors per track

(current emulation mode)

57–58 Number of sectors (current emulation mode)

59–127 Reserved 0000
128–159 Vendor unique 0000
160–255 Reserved 0000

0000

xxxx
xxxx

xxxx
xxxx

H

H

H
H
H

H

H

H

H

H

3.7.8 Set Features (EFH)

This command controls the implementation of various features supported
by the drive. When the drive receives this command, it sets BSY, checks
the contents of the Features register, clears BSY, and generates an
interrupt. If the value in the register does not represent a feature sup­ported by the drive, the command is aborted. Power-on default has the
read look-ahead feature enabled, and 4 bytes of ECC. The acceptable
values for the Features register are defined as follows:

Enable write cache (

02

H

44

Sixteen bytes of ECC apply on read long and write long

H

default

)

commands
Disable read look-ahead (read cache) feature

55

H

66

Disable reverting to power-on defaults

H

82

Disable write cache

H

AA

Enable read look-ahead (read cache) feature (

H

BB

4 bytes of ECC apply on read long and write long commands

H

default

(

CC

Enable reverting to power-on defaults (

H

)

default

default

)

)

At power-on, or after a hardware reset, the default values of the features
are as indicated above (except for write cache, which is enabled or
disabled at power-on). A software reset also changes the features to
default values unless a 66

command has been received.

H

28 ST9100A Product Manual, Rev. A

Bit settings for the Set Features command are shown below.

EF

Command

(1F7

Cyl. High

(1F5

Cyl. Low

(1F4

Drv. Head

(1F6

Sec. Num.

(1F3

Sec. Cnt.

(1F2

Features

(1F1

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

H

1 1 1 0 1 1 1 1

)

H

)

H

)

H

1 0 1 D/S X

)

H

)

H

)

H

)

H

Set Features parameter

X

X

X

X

3.7.9 Active Immediate (F9H)

This command causes the drive to enter Active mode immediately. When
the drive receives this command, it sets BSY, makes a transition to Active
mode, clears BSY and generates an interrupt.

F9

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 1 1 0 0 1

X

X

1 0 1 D/S X

X

X

ST9100A Product Manual, Rev. A 29

3.7.10 Idle and Set Idle Timer (FAH)

This command enables and disables the automatic Idle feature of the
drive. When the drive receives this command, it sets BSY, switches to
Idle mode, and enables or disables the idle timer according to the value
placed in the Sector Count register. The drive then clears BSY and
generates an interrupt.

If the value in the sector count is zero, the idle timer is disabled and the
drive does not automatically switch to Idle mode. If the value is not zero,
the drive switches to Idle mode after the specified delay time has elapsed.

The delay time is specified in the Sector Count register in 100-msec
increments. The delay is reinitialized whenever the drive enters Active
mode.

Note. The factory set default for the Idle timer is five seconds.

FA

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 1 1 0 1 0

X

X

1 0 1 D/S X

X

idle timer delay (in 100-msec increments)

30 ST9100A Product Manual, Rev. A

3.7.11 Active and Set Idle Timer (FBH)

This command enables and disables the automatic Idle feature of the
drive. When the drive receives this command, it sets BSY, switches to
Active mode, and enables or disables the idle timer according to the value
placed in the Sector Count register. The drive then clears BSY and
generates an interrupt.

If the value in the Sector Count register is zero, the idle timer is disabled
and the drive does not automatically switch to Idle mode. If the value is
not zero, the drive switches to Idle mode after the specified delay time
has elapsed.

The delay time is specified in the Sector Count register in 100-msec
increments. The delay is reinitialized whenever the drive enters Active
mode.

Note. The factory-set default for the idle timer is five seconds.

FB

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 1 1 0 1 1

X

X

1 0 1 D/S X

X

idle timer delay (in 100-msec increments)

ST9100A Product Manual, Rev. A 31

3.7.12 Check Idle Mode (FDH)

This command reports whether the drive is currently in or making a
transition to Idle or Active mode. When the drive receives this command,
it sets BSY, loads the appropriate code information into the Sector Count
register, clears BSY and generates an interrupt. The default time delay
before the drive enters Idle mode is five seconds.

Depending on what state the drive is in or making a transition to, one of
the following values is sent:

= The drive is in, or entering, Idle mode.

00

H

= The drive is in, or entering, Active or Standby mode.

FF

H

FD

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 1 1 1 0 1

X

X

1 0 1 D/S X

X

X

32 ST9100A Product Manual, Rev. A

3.7.13 Rest/Resume commands

Some host systems reduce overall power consumption by temporarily
removing power from the disc drive. The Rest/Resume process allows
drive-state information to be saved to disc prior to powering down the
drive. Once power is restored, the drive-state information is retrieved and
used to return the drive to its prerest condition. The drive-state informa­tion is saved in a single 512-byte data block that includes current logical
geometry, set feature parameters, cache status and task file registers.

The Rest/Resume process involves three commands: Rest, Read Drive
State and Restore Drive State. The drive will not recognize and execute
these commands unless the Features register contains the value 0AC
Any other value in the Features register causes the drive to reject the
command with a command abort error.

Note. The Rest/Resume process does not save the contents of data

buffers or caches.

H.

3.7.13.1 Rest (E7H)

The host prepares the drive for a subsequent Read Drive State command
by issuing a Rest command. If two drives (master and slave) are present,
the host must issue the Rest and Read Drive State commands to the
slave prior to issuing them to the master.

Because the Rest mode can be used in addition to the other power
management modes, if the BSY or DRQ bits are set, the host should wait
up to 30 seconds for these bits to clear after the completion of any prior
command. If either the DRQ or BSY bits are set, the host may use the
DASP– signal to determine when to initiate Rest mode. The drive asserts
DASP– when a Rest command is received and negate it upon completion
of the Rest command. After the Rest command is issued, the host should
wait up to 10 seconds for the drive to assert INTRQ.

When the drive receives a Rest command, it captures the state of the I/O
registers as they existed upon completion of the previous command, then
enters Rest mode. After entering Rest mode, the drive rejects any
command other than a Read Drive State command with an aborted
command error. The Rest mode can only be cleared by power off or reset.

After issuing the Rest command, the host should poll the Alternate Status
register to monitor for completion status without clearing the interrupt flag
that may have been set for an application program.

ST9100A Product Manual, Rev. A 33

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

Features

)

(1F1

H

1 1 1 0 0 1 1 1

X

X

1 0 1 D/S X

X

X

0AC

H

34 ST9100A Product Manual, Rev. A

3.7.13.2 Read Drive State (E9H)

The Read Drive State command allows the host system to save certain
drive parameters to nonvolatile system memory before shutting down
power to the drive. The host should only issue this command following a
successful Rest command. If any command other than a Read Drive
State command follows a Rest command, the Rest command is aborted.
If a Read Drive State command follows any command other than a Rest
command, the Read Drive State command is aborted.

If the drive receives a Read Drive State command while in Rest mode,
it transfers essential drive-state information to disc, where the Restore
Drive State command can recover it following power-on.

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

Features

)

(1F1

H

1 1 1 0 1 0 0 1

X

X

1 0 1 D/S X

X

X

0AC

H

ST9100A Product Manual, Rev. A 35

3.7.13.3 Restore Drive State (EAH)

This command allows the host system to restore the drive to the state it
was in at the time of the power-down in Rest mode. If the host has
previously caused a Rest mode, it must ensure that the first command
issued to the drive (after the drive powers up and is ready to accept
commands) is not one that will interfere with the intended resume
operation.

The host should only issue a Restore Drive State command when
powering up the drive after a successful Read Drive State command.
Otherwise the Restore Drive State command is aborted. When the drive
receives a Restore Drive State command, it reads the 256 bytes of
drive-state information that were saved with the Read Drive State com­mand. This drive-state information is checked for validity. If there is a
problem with the data, the drive hangs busy with the trap code set to F5
in all of the AT interface registers. If bit zero of the last word transferred

(reset to 0), INTRQ is not asserted at the completion of this

is 0

H

command. If bit zero of the last word transferred is set to 1, INTRQ is
asserted following the command.

After issuing the Restore Drive State command, the host should poll the
Alternate Status register to monitor for completion status without clearing
any interrupt flag that may have been set for an application program.

H

Command

)

(1F7

H

Cyl. High

)

(1F5

H

Cyl. Low

)

(1F4

H

Drv. Head

)

(1F6

H

Sec. Num.

)

(1F3

H

Sec. Cnt.

)

(1F2

H

Features

)

(1F1

H

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 1 0 1 0 1 0

X

X

1 0 1 D/S X

X

X

0AC

H

Seagate Technology, Inc.
920 Disc Drive, Scotts Valley, California 95066, USA

Publication Number: 36211-001, Rev. A, Printed in USA