Siemens 100-8D User manual

SIEMENS

SIEMENS
Floppy Disk Drive FDD 100-8
INTRODUCTION
OPERATION
THEORY OF OPERATION
INSTALLATION
Technical Manual
Volume 1 Model 100-8D

TABLE OF CONTENTS
1 IN T RO DU CT IO N .................................................................................................... 1-1
General . ................................................................................................................. 1-1
Scope ..................................................................................................................... 1-1
De sc ription ....................................................................................................... 1-1
Disk C a r tr i d g e ................................................................................................ 1-3
Recording F o r m a t ...................................................... ... ............................... 1-5
Encoding S c h e m e ...................... ... ............................................................ 1-5
Track F o r m a t............................................................................................. 1-5
Sector Form at ......................... ... ............................................................ 1-6
Sector Content .................................................................................. 1-6
32-Sector F o r m a t ........................................................................... 1-6
IBM 37 40 Form at ........................................................................... 1-7
Disk Drive A s s e m b l y .................................................................................. 1-8
Printed Circuit Board ............................................................. ... 1-8
Main Deck A s s e m b l y ........................................................................... 1-9
C arrier A s s e m b ly .................................................................................. 1-9
Options-F e a tu re s ......................... ... ................. ... ................. ... ..................... 1-9
Write P r o t e c t ............................................................................................. 1-1
Binary Select ....... ................................ . ............................. 1-10
Radial Select ............................................................................................. 1-10
Hard S e c t o r ................................................................................................ 1-11
16/8 Sector ................................................................................................ 1-11
Auto E r a s e .................................................................................................... 1-11
Data Separator (FM O n ly ) .................. ... ............................... ... 1-11
Auto Head Load . ...................................... ... 1-12
Activity Indicator .................................................................................. 1-12
PCB A ssembly Option C o n fig u ratio n s .................................... 1-12
Spec ificatio n s...................................................................................... ... 1-12
2 O P ERA TIO N ................................ .............................................................................. 2-1
Gene r a l ...................................................................................... ... ........................ 2-1
Daily O pe ration................................................................................................ 2-1
Floppy Disk Handling and S to r a g e ............................................... 2-1
Floppy Disk Loading and Unloading ............... ... 2-2
W rit e -P r o te c t ............................. ... ............................................................ 2-3
ILL
Section Page

TABLE OF CONTENTS (Continued)
3 THEORY OF OPERATION ........................................................................ 3-1
G e n e r a l.............................................................................................................. 3-1
Control S y s t e m ..................... ... . . ....................................................... 3-2
Command Execution .................. ... ................................................... 3-2
Status S e n sin g.......................................................................................... 3-3
Positioning System ................................................................................... 3-3
Stepper Motor C o n t r o l ....................................................... ... 3-3
Stepper M o to r.......................................................................................... 3-4
Carriage A s s e m b ly ............................................................................ 3-4
Read/Write S y s t e m ................................................................................... 3-4
Read/Write Operation ..................................................................... 3-4
Functional D e s c rip tio n ............................................................................ 3-5
Spindle Drive S y s t e m
........................................................................ 3-6
Spindle System . .............................. «............................................ 3-7
Read/Write Head Positioning System ................................... 3-7
Head Load S y s te m ............................................................................... 3-8
Control and Data T im in g .................................................................. 3-8
Logic C onvention s .............. ... .................................................................... 3-10
Detailed Logic D e s cr ip t io n ................................................................. 3-10
Control L o g i c ................................................................................................ 3-10
Select . ............................ ........................................................................... 3-13
Binary Select (Option)........................................................................ 3-14
Index/Sector D e t e ctio n ..................................................................... 3-15
Hard Sector (Option)............................................................................ 3-16
Ready . .............................. ... .......................................................... ... 3 - 16
Activity Indicator .................. ... .......................................................... 3-18
Door Lock (Option) .............. ... ............................................................. 3-19
Disk C h a n g e............................................. ... 3-19
Read/W rite Head Positioning Logic ............................................. 3-20
Head L o a d ................................................................................................ 3-20
Track 00 Switch . ............................................................. ... ................. 3-20
Stepper Motor Drive . ........................................................................ 3-22
Interface Gating. . .......................................................... ... 3-22
State Counter . .................................................................................. 3-22
Stepper Motor Drivers . ............................................................. 3-23
Stepper Motor ............................................................................... 3-24
Read/Write L o g i c ...................................................................................... 3-25
Write-Protect . . ................................................ ... 3-26
Write Mode . ............................................................................................ 3-26
Write and Erase Gating .......................................................... 3-26
Erase L o g i c ....................................................... ... ........................... 3-27
DC U n s a f e .......................................................................................... 3-28
Write Current Control . ............................................................. 3-29
Low Write Current C o n tr o l ............................... ... ................. 3-30
Section Page
iv

TABLE OF CONTENTS (Continued)
3 THEORY OF OPERATION (Continued)
Read M o d e ...................... ... .......................................................................... 3-31
Read/Write S e l e c t ........................................................................... 3-32
Read LSI Circuit, Read Amplifier, and Filter . . . 3-32
Differentiating Network .................. ... . e . s s « ............... . 3-34
Crossover Detector . ...................................................................... 3-35
Time Domain Filter .................................................................... 3-35
FM Data Separator (Option)............................................................. 3-36
Terminating Resistor Network . . .............................................. 3-37
4 INSTALLATION....................................................................................................................... 4-1
G e n e r a l ................................................................ ... .............................................. 4-1
Inspection ............................................................................................ ... 4-1
Unpacking ......................... ... .............................................................................. 4-1
Mechanical Checks .............................................................' ....................... 4-2
Connecting C a b le s ............... ... ..................................................... ... 4-2
AC Power C a b l e ...................................................................................... 4-4
DC Power C a b l e ...................................................................................... 4-5
Interface Signal Cable ............... ... ................. ... ................................ 4-5
Interface Signal Descriptions ............... ... ................................... ... . 4-6
Logic Levels and T e r m in a tio n ...................................................... 4-6
Input S ig n als ................................................................................................ 4-8
Output S ig n a ls............................................................................................. 4-8
Interface T im i n g ....................................... ... ................................................. 4-8
System C o n fig uratio n s ....................................... ... ................................... 4-12
Single-Drive C o n fig u ratio n ............................................................. 4-12
Radial Select......................................................................................... 4-12
Daisy-Chained Radial S e l e c t .................................................. 4-13
Binary S e l e c t .............. ... ............................... ... ............................... 4-14
Interface/Internal Options Installation . .......................................... 4-16
Radial Select ................................ ... ........................................................ 4-16
Binary Select" . .......................................... ... .............................................. 4-18
Radial S te p ............... ... ................................................................................. 4-18
Radial Ready ....................................... ... 4-19
Ready Option ............................................................................................. 4-20
Radial In d e x /S e cto r ............... ... ............................................................ 4-20
Radial Head Load O ption.................................................................... 4-20
Auto Head Load O p tio n ............................. ... ..................... ... 4-21
Hard S e c t o r .............................................. ... ............................................. 4-22
16 or 8 Sector . ................. ... ................................................................... 4-22
Activity Indicator S e l e c t........................................... ... ................. ... 4-22
FM Data Separator . . . ................. ... ................................................. 4-23
Section Page
v

TABLE OF CONTENTS (Continued)
4 INSTALLATION (Continued)
Tunnel-Erase Option . ..................................... ... ........................ ... 4-23
Write Protect O p tio n .............................................................. ... 4-23
Disk Change Option . ........................................................................... 4-24
Phase O p t io n ....................................................... ... .............................. 4-24
Installation .................................................................................................... 4-25
Mounting D im e n sio n s ........................................................................ 4-25
Section Page
vi

LIST OF ILLUSTRATIONS
1-1 Floppy Disk Drive Model F D D 1 0 0 - 8 D .............................................. 1-1
1-2 Floppy Disk and Protective Envelope .............................................. 1-3
1-3 Single and Double Density Encoding .................................................. 1-5
1-4 32-Sector F o r m a t .............................. ... . ........................................ ... 1-6
1-5 IBM 3740 Format ........................................................................................... 1-7
1-6 Physical Dimensions and Mounting p r o v is i o n s .......................... 1-16
2-1 Floppy Disk and Storage Envelope
.............. . . . . ....................... 2-2
2-2 Floppy Disk Loading .................................................................................... 2-3
3-1 Floppy Disk D rive, Simplified Block Diagram .......................... 3-1
3-2 Detailed Functional Block D ia g r a m ..................................................... 3-5
3-3 Spindle Drive S y s t e m ................... ... ............................................................. 3-6
3-4 Spindle S y s t e m .................................................................................................. 3-7
3-5 Read/Write Head Positioning System ............................................... 3-8
3-6 Control and Data T im in g .............................................................................. 3-9
3-7 Interface Logic L e v e l s ..................................................... ... ....................... 3-10
3-8 Logic S y m b olo gy .............................................................................................. 3-11
3-9 Select L o g i c ......................................................................................................... 3-13
3-10 Index Detection Logic .. .............................................................................. 3-15
3-11 Index Timing ..................................................................................................... 3 -lo
3-12 Hard Sector and 16/8 Sector Option L o g i c .................................... 3-17
3-13 INDEX/SECTOR T im i n g .............................................................................. 3-17
3-14 Ready L o g i c ........................................................................................ ... 3-18
3-15 Head Load L o g ic ............................................................................................... 3-19
3-16 Track 00 L o g ic ................... ... .......................................................................... 3-21
3-17 Track 00 Timing .. ............................................................................................ 3-21
3-18 Stepper Motor Interface Gating L o g i c ............................................... 3-22
3-19 Stepper Motor Timing ................................................................................. 3-23
3-20 Stepper Motor Drivers Logic ................................................................ 3-24
3-21 Write Initiate T im in g
........................ ... .................* .................................. 3-25
3-22 W rite-Protect Logic ......................................................... ... ....................... 3-26
3-23 Write and Erase Gating L o g i c
................ ... ................. ... . .................... 3-27
3-24 E rase L o g i c ......................................................................................................... -*-28
3-25 Erased Data P a t t e r n ........................ ... .................... ... . .................... ... . 3-29
3-26 DC Unsafe L o g i c ................................................................................. ... 3-29
3-27 Write Current Control Logic . . . . . . .............................. ... 3-30
Figure Page
vii

LIST OF ILLUSTRATIONS (Continued)
Figure Page
3-28 Write Current S w itc h in g ............................................................................ 3-31
3-29 Write Current Timing ................................................................................ 3-32
3-30 Read Initiate Timing .................................................................................... 3-33
3-31 Read Logic, Simplified Diagram ........................................................ 3-33
3-32 Read Preamplifier and Filter C i r c u it .............................................. 3-34
3-33 Differentiating Network....................................
... ......................................... 3-34
3-34 Read Data Waveforms .......................................... ... .................................. 3-35
3-35 Time Domain Filter Logic ...................................................................... 3-35
3-36 FM Data Separator (Option) Logic ..................................................... 3-35
3-37 FM Data Separator Output Timing ..................................................... 3-36
3-38 Terminating R esistor N etw o rk............................................................... 3-37
4-1 Principal Parts Location............................................................................. 4-3
4-2 AC Connector J 2 .............................................................................................. 4-5
4-3 DC Connector J 2 .............................................................................................. 4-5
4-4 Interconnecting D ia gram ............................................................................. 4-7
4-5 Single-Drive Configuration............................................................ ... 4-12
4-6 Radial Select Configuration...................................................................... 4-13
4-7 Daisy-Chained Radial Select C onfiguration.................................... 4-14
4-8 Binary Select Configuration ...................................................................... 4-15
4-9 Interface/internal O p tions.......................................................................... 4-17
viii

LIST OF TABLES
1-1 Floppy Disk C h a ra c t e r i s tic s .................. ... ........................................ . 1-4
1-2 Principal S p e cific a tio ns ....................................... ... ............................ ... . 1-13
2-1 Floppy Disk Loading and Unloading . , . ........................ ... , , . . 2-3
3-1 Disk Drive Selection ........................................................................ ... 3-14
4-1 AC Power R equ irem e n ts............................................................................ ... 4-4
4-2 DC Power Requirements . .............................................................................. 4-5
4-3 Recommended J3 Mating C onnecto rs.................................. ... 4-6
4-4 Interface Input S ig n a l s ..................................... ... .......................................... 4-9
4-5 Interface Output Signals , , , , .. .............................................. ... 4-11
Table Page
ix

SECTION 1
INTRODUCTION
GENERAL
This manual provides information on the de
theory of operation information for the Mod
(Figure 1-1).
SCOPE
The contents of this manual are intended
to be used for customer introduction to the
disk drive, as a training document for
custom er engineers requiring detailed
theory of operation information and for
installation and maintenance information.
DESCRIPTION
The disk drive is a low-cost, random
access storage device, which uses a
floppy disk as the storage medium. The
single, removable disk cartridge will
store up to 6. 4 megabits of double-density
unformatted data, 3. 2 megabits of single-
density data, or 1. 94 megabits using the
compatible IBM system 3740 format. The
disk drive is also compatible with the IBM
size and w’eight, installation can be accoi
location or orientation. For data accessin
cription, capabilities, operation, and
1 FDD 100-8D Floppy Disk Drive
Figure 1-1. Floppy Disk Drive
Model FDD 100-8D
System 32 format. Because of its small
nplished in almost any convenient
I the disk is divided into 77 tracks, and
1-1

each track can be subdivided into as many as 32 sectors. A stepper motor positions
the read/write head at the track to be accessed . Index and sector holes punched into
the disk are sensed photoelectrically to produce sector and index pulses that permit
accessing the individual sectors of a track. When the optional write-protect slot in
the protective envelope is uncovered the write-protected condition is sensed photo
electrically, and write operations are inhibited.
Up to eight drives can be interfaced to a single host controller. The controller
controls disk drive selection, head loading, track addressing, and read/write data
transfers.
When a disk cartridge is inserted and the access door is closed, the drive spindle
rotates the disk at 360 revolutions per minute. When selected, the drive accepts
a head load command, causing the read/write head to be loaded to the disk. With
the drive selected, sector/index pulses, write-protect status, track 00 position
status, and a read/write ready status is supplied to the controller. At the desired
track, a data transfer operation is performed; read-to the controller, w rite-from
the controller, depending on the state of the write command.
During a write operation (disk not write-protected), write data is input to the write
circuits. For each write data pulse received, a flux reversal is recorded on the
disk by the read/write head.
During a read operation, each recorded flux reversal is sensed by the read/write
head, converted to a raw data pulse and supplied to the controller.
Applications for the Floppy Disk Drive include:
• Key Entry System s
• Point-of-Sale Recording Systems
• Word Processing System s
• Batch Terminal Data Storage
• Small Business Systems Data Storage
• M icroprogram Loading and Error Logging
• Minicomputer Program s and Auxiliary Data Storage
1-2

The drive provides random accessing of data with greater performance and
reliability and is an excellent alternate product to paper tape, reel-to - reel tapes,
card equipment, cassettes, and cartridge drives.
DISK CARTRIDGE
The disk cartridge is an 8 -inch-square plastic protective envelope, in which the
floppy disk is sealed. The protective envelope contains apertures for spindle load
ing, head contact, sector/index detection, and optional w rite-protect detection,
(see Figure 1 -2).
The recording media is a magnetic-oxide-coated floppy (flexible) mylar disk sealed
within the plastic envelope for protection, self-cleaning, and ease of handling. The
disk should be handled and stored in clean environments, free from magnetic
influences.
Figure 1-2. Floppy Disk and Protective Envelope
1-3

At no time should the surface of the media be touched, or the surface of the
envelope be written on. When not in use, the disk cartridge should be returned
to its protective storage envelope.
For reliable operation, floppy disks should be stabilized in the same environment
as the using disk drives, for a period of at least five minutes, prior to installation.
The recommended floppy disk m eets the requirements of the following documents:
X3138/77-118 Am erican National Standard for Single Sided
Unformatted Flexible Disk Cartridge.
GA21-9190 IBM One-Sided, Original Equipment Manufacturing
Information.
ECMA/TC 1 9/? 7 /l6 Data Interchange on 200 mm Disk Cartridges using
double frequency recording at 13,262 ftprad on one
side.
Floppy disk characteristics are listed in Table 1-1.
Table 1-1. Floppy Disk Characteristics
Function Characteristics
Disk Type ANSI Standard
Disk Diameter 7. 88 inches
Disk Thickness 0. 003 inch
Rotational Speed 3 60 rpm
Rotational Period 166. 67 ms
Average Latency 83. 33 ms
Tracks 77
Track Density 48 tpi
Bit Density 3268 bpi (single density)
6536 bpi (double density)
Note: For minimum runout the floppy disk should be loaded while the spindle is
turning.
1-4

RECORDING FORMAT
The recording format ls dependent upon requirements of the controller. The track
and sector organization of data Is dependent on the format.
Encoding Scheme
The drive allows double-densIty or s Ingle-dens Ity encoding schemes. In double-
density recording, each bit cell Is 2 microseconds wide, In s ingle-dens Ity rec o rd
ing, each bit cell Is 4 microseconds wide (see Figure 1-3).
Track Form at
The floppy disk contains 77 tracks. The first (outside) track is track 00, and the
last (Inside) track Ls 76. During the write operation, an erase coll in the
read-wrlte head erases the outside edges of the data just written, narrowing the
data track. In this manner, a guard band Is established to protect the data from
adjacent track crosstalk when reading.
-► 1 CELL
12 mSEC -* - ( 5 0 '0 KBS)
1100 I 0 11 1 001
WRT DATA FT
- ► ] 2 mSEC f— -
I I
I I
I I
j u i m j u if
CLOCK CLOCK DATA DATA DATA
DOUBLE-DENSITY ENCODING (MFM)
CLOCK DATA
-BIT CELL
4 iuSEC (250 KBS)
11000 1
Ii i ! i i
WRT DATA
i n n n n r
¥u n n r
j2 mSEC h - CLOCK DATA CLOCK CLOCK CLOCK
SING LE-DENSITY ENCODING (FM)
CLOCK DATA CLOCK
Figure 1-3. Single and Double Density Encoding
1-5

Sector Format
The number of sectors In each track Is determined by the application, and can
range from 1 to 32, depending on whether the soft-sector or hard-sector floppy
disk is being used.
When soft sector operation is required, only one index hole is punched in the floppy
disk. With this disk, the controller uses the index pulse to define the sectors.
When hard sector operation is required, the floppy disk used contains the index
hole plus 32 sector holes spaced equidistant around the disk (see Figure 1-2).
The index hole is punched midway between sector holes 31 and 0. The double-
pulse of sector 31 and index alerts the controller that the next pulse starts sector 0.
The index and sector holes are sensed photoelectrically, providing the pulses sup
plied to the controller.
Sector Content
The format of each sector is determined by the application. Normally, preambles
and postambles containing a stream of coded bytes are written at the beginning and
end of each sector, to provide data synchronization. Following the preamble of
each new track, an identification (ID) field is written containing the track and sector
numbers. Following the ID field, data bytes are written.
32-Sector Format
This format is not the m ost efficient OEM format due to the number of gaps
required between data records. The IBM 3740 format requires even more gaps
but is accepted as the m ost compatible. A typical 32-sector format is shown in
Figure 1-4.
SECTOR SECTOR
PREAMBLE DATA RECORD POSTAMBLE
Figure 1-4. 32-Sector Form at
1-6

IBM 3 740 Form at
There are two IBM 3740 formats; Data Set Label and Track. The disk drive is
compatible to both formats.
Track 00 contains only Data Set Labels that identify the type of information stored
in tracks 01 through 7 6. Tracks 01 through 73, 75, and 76 are allocated 26 sectors,
each containing 128 data bytes. A data set m ay be one or m ore sectors, including
overflow to other on-line disk drives. In the drive, only tracks 01 through 73 are
normally used. Track 74 and 75 are reserved as spares to be used when other
tracks become flawed, track 76 is not used. The IBM 3740 format is shown in
Figure 1-5. F or detailed information on the IBM 3740 data format and initialization
refer to IBM Publication GA21-9190.
166-2/3 MSEC
J— L
OPTICAL INDEX
TRACK FORMAT
BYTES
J— L
POST
INDEX SECTOR 1 SECTOR 26 TRAILING GAP 247 BYTES OF HEX FF OR 00
73 188 188 247 (VARIES WITH TOL)
POST INDEX FIELD FORMAT
BYTES 40 6 126 !
HEX VALUE FF OR 00 00 FF OR 00 j
INDEX ADDRESS MARK
HEX FC DATA BIT PATTERN
HEX D7 CLOCK BIT PATTERN
BYTES
ID
FIELD
GAP FF
OR 00 DATA FIELD GAP FF
OR 00
13 1 1 137 27
BYTES
HEX VALUE
BYTES
HEX VALUE
DATA FIELD FORMAT
ID FIELD FORMAT
6111112
00 FE 00 00 CRC
CYCLIC REDUNDANCY
CHECK CHARACTERS
tL SECTOR NUMBER IN BINARY
TRACK NUMBER IN BINARY
L ID ADDRESS MARK HEX C7 CLOCK BIT PATTERN
61128 2
00 FB DATA CRC
IDATA ADDRESS MARK HEX C7 CLOCK BIT PATTERN
Figure 1-5. IBM 3 740 Frc
1-7

DISK DRIVE ASSEMBLY
The disk drive assem bly can be installed in a standard 19-inch RETMA rack; two
horizontally, or four vertically. The drive can also be mounted in a table-top for
top loading applications.
The disk drive comprises three major assemblies-
• Printed Circuit Board (Electronics)
• Main Deck Assembly
• Carrier Assem bly
Printed Circuit Board
All electronic circuitry required to convert the digital data input and output to
and from analog data for the read/write head and head positioning information is
contained on one circuit board. Interface and DC connectors can be provided.
Logic is TTL with selected discrete and IC Components. The electronics perform
the following functions:
• Read Chain
• Write Chain
• Ready Generation
• Index Detection
• Stepper Motor Control
• Interface Drivers and Receivers
• W rite-Protect (Option)
• Index/Sector Separator (Option)
• FM Data Separator (Option)
• Binary Select (Option)
1-8

Main Deck Assembly
The main deck assembly is the principal supporting assembly and contains the
following subassemblies;
Drive System
Positioning Svstem
Read Write S vs tern
Disk Cartridge Guide
and Ejector
Optical Sensing
- Spindle Drive motor, drive belt and pulley to
rotate spindle at 360 rpm.
- Stepping motor, lead screw and carriage, head
pressure a rm and pressure pad to accurately
drive and position the read write head to the
desired track.
- Single-gap magnetic recording head with tunnel -
erase or s t raddl e - e rase feature. Read/write
head is contact type.
- Provides positive positioning and locking of disk
cartridge allowing proper placement of the disk
cone. Spring-loaded ejection provides fast,
positive disk cartridge removal.
- Index and write - protect sensing by independent
LED and phototransistor sensing circuits. Also
track 00 sensing.
C arrier Assembly
The carrie r assembly is a secondary frame which pivots from the main deck
assembly and includes the following subassemblies;
• Disk Centering Cone - Precisely centers and grips the floppy disk to the
s pindle.
• Head Load Mechanism - Solenoid, head pressure arm and pad. Exerts
and sustains force, by the spring-loaded pressure
pad, to constrain the disk cartridge to the platten
and the read, write head.
Access Handle. Pushbutton latch release mechanism. Also
releases spring-loaded lock to discharge disk
cartridge.
OPTIONS-FEATURES
The Floppy Disk Drive may be ordered with basic configuration operating capa
bilities, or may be ordered to include any or all available options. Each option
1-9

offers unique operating features. Several options have connections designed into
the main printed circuit board, for low -cost customer enhancement.
W rite-P rotect
The write-protect feature provides a write-inhibit function when a write-protect
floppy disk cartridge is used. The stored data is protected only if the cartridge
write-protect slot is present. With the slot covered, all write functions are
enabled.
Binary Select
The Binary Select option permits any one of up to eight disk drives to be selected.
With the option installed, SELECT lines are not dedicated but are used to contain a
binary select code. The SELECT 0 line is used to enable/disable unit selection,
while the SELECT 1, SELECT 2, and SELECT 3 lines contain a binary code between
0 and 7. When the SELECT 0 line is low (true), a decoder in the Binary Select
option logic decodes the select code from the controller.
Radial Select
In the basic configuration, the disk drive does not accept commands from the
controller, and does not supply status signals to the controller, until selected.
The purpose of this option is to allow commands to be accepted and status signals
to be supplied, each over separate lines, without the drive selected. The following
signals can be optionally configured for radial operation:
• STEP and STEP IN (Step Command)
HDLD (Head Load Command)
• READY (Ready Status)
• INDEX and SECTOR (Index and Sector Pulses)
When dedicated lines are provided for these signals, the disk drive need not be
selected by the controller. Each line must be assigned a separate pin number on
the interface connector. Spare pins are provided for this purpose.
1-10