Tandon TM848-1E User manual

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PRODUCT SPEfi~~~l1ijN ~ USER'S MANUAL

NOTICE
This document, and the information contained herein, is copyright by Tandon Corporation and
may not be duplicated or reproduced, in whole or in part, without the prior written approval of
Tandon Corporation.
This document is intended to provide the user with detailed information adequate for the efficient
installation, operation, and service of the equipment involved.
However, while every effort has been made to keep the information contained herein current and
accurate as of the date of publication, no guarantee is given or implied as to its accuracy.

TM848-1E, TM848-2E
THINLINE™ FLEXIBLE DISK DRIVE
48 TRACKS
PER INCH
PRODUCT SPECIFICATION AND
USER'S MANUAL
'anaiiii CORPORATION
20320 PRAIRIE STREET
CHATSWORTH, CALIFORNIA 91311
©COPYRIGHT 1983 TANDON CORPORATION

Section
Number
SECTION 1
Title
GENERAL DESCRIPTION
CONTENTS
Page
Number
1.1
1.2
1.3
1.4
1.5
SECTION 2
2.1
2.2
2.3
2.4
SECTION 3
Introduction. .............................................................. 1-1
Scope
Of The Document.... .. .. .. ......... .. .. .. .. . .. 1-1
Purpose Of The Drive 1-1
Major Features.... . . .. .. .. . .. . .. .. . . .. ....... . . . .. . . .. 1-1
Microprocessor Control 1-1
Write Protect 1-1
Daisy Chain Capability... . .. . .. . . .. . . . .. .. . . . . . .. 1-1
Internal Trim Erase.. . . . . .. .. .. . .... 1-2
Industry Standard Interface Compatibility. .............................. 1-2
Acti vi ty Indica tor ....................................................... 1- 2
Direct Drive, Brushless D. C. Motor. ...................................... 1-2
Com
pact Size ............................................................ 1- 2
Diskette Lever Lock Solenoid.. .. . .. . . . . .. . . .. . . . .. 1-2
Functional Description 1-2
Power On Self-Tests '" 1-3
Physical Description. ...................................................... 1-3
PRODUCT SPECIFICATIONS
Introduction. .............................................................. 2-1
Mechanical Specifications 2-1
Electrical and Operational Specifications. .................................. 2-1
Reliability Specifications. .................... .. .. ......................... 2-1
Environmental Specifications. ............................................. 2-1
OPERATION
3.1
3.2
3.3
3.4
3.5
3.6
Introduction .
Unpacking The Drive .
Pre installation Checkout .
Mounting The Drive .
Dust Cover .
Cooling .
Interface Connections .
Input Control Lines .
Output Control Lines .
Typical Interface Characteristics .
D.C.Power .
Dri ve Address and Option Strapping .
Drive Select (DS1-DS4) .
Head Select Options (Sl-S3 and 1B-4B) .
Stepper Motor Power (PS, PS*, DS, HL) .
Spindle Motor Control Options (M1, M3, M4, MOL, MOH, MC1-MC4) .
Ready and True Ready (R and TR) .
Lever Lock Options (D, DL, LL, NL) .
Disk Change (DC) .
Two-Sided
Diskette Installed (2S) .
Wri te Protect (WP and NP) .
Write Current Switch (XC and IC) .
Diagnostic Mode of Operation (DM, DL, M1, M3, M4) .
i
3-1
3-1
3-1
3-1
3-2
3-2
3-2
3-2
3-5
3-6
3-6
3-8
3-8
3-8
3-10
3-10
3-13
3-13
3-13
3-13
3-13
3-14
3-14

Section
Number
3.7
Figure
Number
1-1
2-1
2-2
2-3
3-1
3-2
3-3
3-4
3-5
3-6
Table
Number
2-1
2-2
2-3
3-1
3-2
3-3
3-4
Title
Diskettes .
Loading The Diskette .
Write Protect Tab .
Diskette Handling and Storage .
ILLUSTRATIONS
FIGURES
Title
Disk Drive .
Disk Drive Outline Drawing .
+ 24 Volt D. C. Current, Configuration 1 .
+ 24 Volt D. C. Current, Configuration 2 .
Electrical Interface Characteristics .
Control and Data Timing Requirements .
LSI Circuit Board Assembly .
Non-LSI Circuit Board Assembly .
Recording Media .
Diskette Care and Handling .
TABLES
Title
Electrical and Operational Specifica tions .
Reliability Specifications .
Environmental Specifications .
Drive Interface Lines and Pin Assignments .
D. C. Power Connector Pin Assignments .
Option Patching .
Diagnostic Mode Of Operation .
ii
Page
Number
3-14
3-14
3-14
3-17
Page
Number
1-4
2-2
2-5
2-5
3-6
3-7
3-11
3-12
3-17
3-18
Page
Number
2-3
2-6
2-6
3-3
3-8
3-9
3-15

SECTION 1
GENERAL DESCRIPTION
INTRODUCTION
This document provides required information
in order to evaluate or incorporate Tandon's
disk drive into a system.
Tandon Corporation's Model Numbers
TM848-1E and TM848-2E, eight-inch flexible
drives are full-feature, microprocessor-
controlled drives. They may be installed in
one-half the space normally required for an
eight-inch drive. They are compact data stor-
age devices that use an IBM-formatted, indus-
try standard, eight-inch diskette. Both drives
are 48 tracks per inch recording devices.
The Model TM848 series of drives are capable
of reading and wri ting in single-density
format on a diskette, using a proprietary
read/write head patented by Tandon. In
addition, both drives have a double density
capability when Modified Frequency Modula-
tion (MFM) or other appropriate recording
techniques are used. The encoding and decod-
ing of the data is done by the user's controller.
The Model TM848-1E drive uses one side of
the diskette for data storage. The Model
TM848-2E
drive doubles data storage capabili-
ties by using both sides of the diskette.
1.1 SCOPE OF THE DOCUMENT
This document contains a description of the
major features, physical and functional speci-
fications, mounting and power requirements,
the interface, and typical timing characteris-
tics of the TM848-1E and TM848-2E drives.
1.2 PURPOSE OF THE DRIVE
The TM848-1E and TM848-2E drives are
rotating disk memories designed for random
access data entry, storage, and retrieval
applications. Typical applications include
1-1
intelligent terminal controllers, micro-
computers, word processing systems, data com-
munication systems, error logging, program
loading, and point-of-sale terminals.
1.3 MAJOR FEATURES
MICROPROCESSOR CONTROL
The TM848-1E and TM848-2E drives feature
an onboard microprocessor. This microproces-
sor provides six major features:
1. Buffered seek capabilities ..
2. Improved head positioning accuracy
wi th reduced hysteresis.
3. Write current switching for optimal
data recording quality.
4. True Ready signal.
5. Internal diagnostics (strappable).
6. Power On Self-Tests.
WRITE PROTECT
When a write protected diskette is inserted
in to the dri ve, the wri te electronics are
disabled.
DAISY CHAIN CAPABILITY
The drive provides the address selection and
ga ting functions necessary to daisy chain a
maximum of four units at the user's option.
The last drive on the daisy chain terminates
the interface. The terminations are accom-
plished by a resistor array plugged into a DIP
socket.

INTERNAL TRIM ERASE
The drive provides the control signals neces-
sary for proper trim erasure of data.
INDUSTRY STANDARD INTERFACE
COMPATIBILITY
The drive is compatible with controllers that
use an industry standard interface.
ACTIVITY INDICATOR
An activity indicator, located on the front
panel, is automatically illuminated when the
drive is selected. This front panel L.E.D. is
also used as an indica tor in the diagnostic
mode.
DIRECT DRIVE, BRUSHLESS D. C.
MOTOR
The spindle motor is a crystal controlled,
direct drive, brushless D. C. motor for
improved motor start time, and speed
accuracy.
COMPACT SIZE
The reduced size of the drive occupies only
one-half the mounting space required for a
conventional drive.
DISKETTE LEVER LOCK SOLENOID
The diskette lever lock solenoid is controlled
by the host system.
1.4 FUNCTIONAL DESCRIPTION
The drives are fully self-contained, and
require no operator intervention during
1-2
normal operation. Each drive consists of a
direct drive, spindle system, a head positioning
system, and a read/write system.
The TM848-1E is a single-sided drive. The
TM848-2E is adouble-sided drive. The only
difference between the two drives is the
number of heads. The circuit board is identical
for both models.
When the diskette lever is opened, access is
provided for the insertion of a diskette. The
diskette's jacket is accurately positioned by
plastic guide rails. Its location is ensured by
the back stop and disk ejector.
Closing the diskette lever activates the
cone/clamp system, resulting in accurate
centering and clamping of the diskette to the
drive hub. The drive hub is driven at acon-
stant speed of 360 RPM by a crystal-
controlled, direct drive, brushless D. C. motor.
The head is loaded in to con tact with the
recording medium whenever the diskette
lever is latched.
The heads are positioned over the desired
track by means of a stepper motor/band
assembly and its associated electronics. This
positioner uses a3.6 degree rotation to cause a
one track linear movement.
When a write-protected diskette is inserted
into the drive, the Write Protect sensor dis-
ables the write electronics of the drive, and a
Write Protect status output signal is available
to the interface. When performing a write
operation, a0.013-inch wide, nominal, data
track is recorded. Then, this track is tunnel
erased to 0.012-inch, nominal.
Data recovery electronics inel ude alow-level
read amplifier, filter, differentiator, zero
crossover detector, and digitizing circuits. No
data-clock separation is provided.
In addition, the drive is supplied with the fol-
lowing sensor systems:
1. A Track 0 sensor detects when the
Head/Carriage Assembly is positioned
over Track o.
2. The TM848-2E has two index sensors,
each consisting of an infrared L.E.D.

light source and a phototransistor, posi-
tioned to generate a signal w hen an
index hole on the diskette is detected.
The drive can determine if asingle-
sided or double-sided diskette is
installed. This ou tpu t signal is present
at the interface.
3. A Write Protect sensor disables the
write electronics when a write-enable
tab is removed from the diskette.
POWER ONSELF- TESTS
The drive conducts a power on self-test as part
of the normal power on sequence. Two of the
tests do not require a diskette to be inserted.
These tests are: the head carriage stepping in,
away from, Track 0, and the head carriage
stepping out toward Track O. Failure of either
of these tests is indicated on the front panel
L.E.D. by the following flashing sequence:
3 flashes, then 2: Fails to step in from
Track 0 or Track 0
sensor is always equal
to zero.
3
flashes, then 3: Fails to step out to
Track 0 or Track 0
sensor is always equal
to one.
A
third test monitors the index sensors when-
ever the diskette lever is closed, and must
have a diskette inserted into the drive. If the
diskette lever is closed wi thou t a diskette in
place, or the spindle motor fails to operate, an
error message flashes on the fron t panel
L.E.D. in the following sequence:
3 flashes, then 4: No index pulse wi th
lever closed.
1-3
Opening and closing the diskette lever is
required to repeat a test that has failed. The
diskette lever must be left open to complete
an error cycle.
1.5 PHYSICAL DESCRIPTION
A represen ta ti ve drive is shown in Figure 1-1.
The drive can be mounted in a vertical or hori-
zon
tal plane. However, the logic circuit board
must be on the uppermost side when the drive
is mounted horizontally.
The spindle is rotated by a direct drive, brush-
less D. C. motor with an integral tachometer.
The crystal-controlled servo circuit and
tachometer control the speed of the spindle.
Operator access for diskette loading is pro-
vided via a horizontal slot located at the front
of the drive.
The read/write double-head assembly is posi-
tioned by a split band positioner mounted to a
microprocessor-controlled stepper motor. The
read/write heads are glass-bonded, ferrite/
ceramic structures with a life expectancy of
15,000 operating hours.
The con trol electronics of the dri ve are
moun ted on a prin ted circui t board located
above the chassis. Power and interface signals
are routed through connectors plugging
directly in to the logic circuit board. Asecond
circuit board, mounted under the drive, oper-
ates the brushless D. C. spindle motor.

FIGURE 1-1
OISI{ DRIVE

SECTION 2
PRODUCT SPECIFICATIONS
INTRODUCTION
This section contains the mechanical, electrical, reliability, and environmental specifications for the
TM848-1E and TM848-2E drives.
2.1 MECHANICAL SPECIFICATIONS
Figure 2-1 contains the physical dimensions of the drive.
2.2 ELECTRICAL AND OPERATIONAL SPECIFICATIONS
The electrical and operational specifications are located in Table 2-1.
2.3 RELIABILITY SPECIFICATIONS
The reliability specifications are located in Table 2-2.
2.4 ENVIRONMENTAL SPECIFICATIONS
The environmental specifications are located in Table 2-3.
, a n aDnCORPORATION, CHATSWORTH, CALIFORNIA 91311
2-1
179049-001
REV.A