Qume QumeTrak 242 User manual

ume
A Subsidiary of ITT
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QumeTrak 242
Maintenance Manual
February 1983
2350 Qume Drive •San Jose, California 95131 •TWX 910-338-0232 •[phone]

Reorder Number 36057
© 1983 Qume Corporation
Qume, Q, QPW, QumeTrak, Quickload, QVT, Sprint, Sprint Micro, SpeedFeed, Twintellect,
TwinTrack,
WideTrack, and MicroDrive are Trademarks of Qume Corporation.
Contents of this publication may be preliminary and/or may be changed at any time without notice and shall not be regarded as a
warranty.

FOREWORD
This manual is one of a group of publications concerning the
QumeTrak 242 flexible disk drive. Each manual documents the
entire disk drive, but from a different aspect. Some subjects may
be found in more than one publication, with the text description
being
more or less technically detailed as required for the
intended reader.
Title
QumeTrak 242 Product Description
Memory Products Service and Spares Catolog
Publication Number
36053
37052
i

TABLE OF CONTENTS
....................................................
Interface ••••••••••••••••••••••••••••••••••••••••••
I NSTAlLATI ON •.•.•.••••••••••••••••••••••••••••••••••••.••••.•••
I NTRODUCTI ON •••••••••••••••••••••••••••••••••••••••••••••••••••
Page
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iii
Interface ••••••••••••••••••••••••••••••••••••••••
....................................................
Input Lines .....•.........•.•...........•........•..........
Drive Select 1-4 ••••••••••••••••••••••••••••••••••••••••
Direction .
Step ............................•.......................
Write Data ••••••••••••••••••••••••••••••••••••••••••••••
Write Gate •••.•..•••.••••••••••.•.••••••••.••.•.••••••••
Side Select •••••••••••••••••••••••••••••••••••••••••••••
Low Current/Switch Filter •••••••••••••••••••••••••••••••
Head Load ••••••• · ••••••••••••••••••••••••••••••••••••••••
In Use ••••••••••••••••••••••••••••••••••••••••••••••••••
Output Lines ••••••••••••••••••••••••••••••••••••••••••••••••
Index .
Rea dy •••••••••••••••••••••••••••••••••••••••••••••••••••
Track OO ••••••••••••••••••••••••••••• ~ ••••••••••••••••••
Write Protect •••••••••••••••••••••••••••••••••••••••••••
Read Data ••.••••••••••••••••.•••••••••••••••••••.•••.••.
Disk Change •••••••••••••••••••••••••••••••••••••••••••••
Two-S i ded •••••••••••••••••••••••••••••••••••••••••••••••
Alternate I/O Pins ••••••••••••••••••••••••••••••••••••••••••
Scope of Manual •••••••••••••••••••••••••••••••••••••••••••••
General Description •••••••••••••••••••••••••••••••••••••••••
Specifications Summary ••••••••••••••••••••••••••••••••••••••
Compati bi 1 ity •••••••••••••••••••••••••••••••••••••••••••••••
Read/Write/Erase Head •••••••••••••••••••••••••••••••••••
Read Output Level •••••••••••••••••••••••••••••••••••••••
Write Current •••••••••••••••••••••••••••••••••••••••••••
Switch Filter •••••••••••••••••••••••••••••••••••••••••••
Track Positioning •••••••••••••••••••••••••••••••••••••••••••
Index Positioning •••••••••••••••••••••••••••••••••••••••••••
Receiving and Inspection ••••••••••••••••••••••••••••••••••••
Mou nt in g ....•.•••••••••••••••••••.•.••••••••••••••.•..••••••
Mechanical Dimensions •••••••••••••••••••••••••••••••••••
Recommendations •••••••••••••••••••••••••••••••••••••••••
Installation Requirements •••••••••••••••••••••••••••••••••••
Timing
Physical
Connectors
and Cables •••••••••••••••••••••••••••••••••••••••
I/O Signals (Pl/Jl) •••••••••••••••••••••••••••••••••••••
Power (P5/J5) •••••••••••••••••••••••••••••••••••••••••••
T ermi nators •••••••••••••••••••••••••••••••••••••••••••••••••
INTERFACE
El ectri cal

TABLE OF CONTENTS (Cont)
Page
CUSTOMER STRAPPABLE OPTIONS •••••••••••••••••••.••••••••••••••••
Genera 1 ••••••••••••••••••••••••••••••••••••••••••••••••••••
Programmable Shunt ••••••••••••••••••••••••••••••••••••••••••
Drive Select Options ••••••••••••••••••••••••••••••••••••••••
Option 1 ..•..•.....•..•..••••••....••••.••...•.•.•..•.••
Option 2 .
Head Load Options •••••••••••••••••••••••••••••••••••••••••••
Option 1 .
Option 2
................................•....•..........
Option 3 ..••••.••.•.....•.....•••..•....••••.•.•..•.....
Side Select Options •••••••••••••••••••••••••••••••••••••••••
Option 1 .
Opt i on 2 ••••••••••••••••••••••••••••••••••••••••••••••••
Radial Ready Option •••••••••••••••••••••••••••••••••••••••••
Radial Index Option •••••••••••••••••••••••••••••••••••••••••
In Use Options ••••••••••••••••••••••••••••••••••••••••••••••
Opt i on 1 ..••....••••...•••..••••••.•..•..••••..•..•...••
Option 2 ...............••.•..........•.................•
Option 3 ...•......••....•..••.••.••... " ..•............••
Door Lock Latch Option ••••••••••••••••••••••••••••••••••••••
Write Protect Option ••••••••••••••••••••••••••••••••••••••••
Disk Change (Alternate Output) ••••••••••••••••••••••••••••••
Two-Sided (Alternate Output) ••••••••••••••••••••••••••••••••
21
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24
24
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~I NTENANCE ••••••••••••••••••••••••••••••••••••••••••••••••••••
Preventive Maintenance ••••••••••••••••••••••••••••••••••••••
Checks and Alignment ••••••••••••••••••••••••••••••••••••••••
Index Lamp Assembly •••••••••••••••••••••••••••••••••••••
Index Sensor Assembly •••••••••••••••••••••••••••••••••••
Track 00 Sensor Assembly ••••••••••••••••••••••••••••••••
Write Protect Sensor Assembly •••••••••••••••••••••••••••
Carrier Assembly ••••••••••••••••••••••••••••••••••••••••
Pop-Up Assembly •••••••••••••••••••••••••••••••••••••••••
Head Load Solenoid Assembly/Head Gap ••••••••••••••••••••
Read/Write (R/W) Head Radial Positioning ••••••••••••••••
Read/Write (R/W) Head Azimuth •••••••••••••••••••••••••••
Read/Write (R/W) Head Amplitude •••••••••••••••••••••••••
Subassembly Removal and Installation ••••••••••••••••••••••••
Track 00 Sensor Assembly ••••••••••••••••••••••••••••••••
Write Protect/Motor On Sensor Assembly ••••••••••••••••••
Head Load Solenoid Assembly •••••••••••••••••••••••••••••
Door Lock Solenoid Assembly •••••••••••••••••••••••••••••
In Use LED ••••••••••••••••••••••••••••••••••••••••••••••
Index Lamp Assembly •••••••••••••••••••••••••••••••••••••
Index Sensor Assembly •••••••••••••••••••••••••••••••••••
Main Printed Circuit Board (PCB) ••••••••••••••••••••••••
Steel Belt ••••••••••••••••••••••••••••••••••••••••••••••
iv
General ....................................................
29
29
32
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34
34
34
36
38
40
41
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43
45
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49
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52

TABLE OF CONTENTS (Cont)
Page
Stepper Motor ••••••••••••••••••••••••••••••••••••••••••• 53
Head Carriage Assembly.................................. 54
Motor Control PCB Assembly •••••••••••••••••••••••••••••• 56
Drive Motor............................................. 56
Front Bezel, Push Button, and Front Door •••••••••••••••• 57
Media Guide, Pop-Up Assembly •••••••••••••••••••••••••••• 57
Carrier Assembly........................................ 58
Collet Assembly ••••••••••••••••••••••••••••••••••••••••• 58
TROUBLESHOOTING .........................•...................... 59
General .•..•.••••..•.••.•••.••.••••••••..•..••••••••••....• 59
Definitions of QumeTrak 242 Functional Errors............... 59
Troubleshooting Technique ••••••••••••••••••••••••••••••••••• 59
Troubleshooting Flowchart Routines •••••••••••••••••••••••••• 60
RECOMMENDED SPARE PARTS •••••••••••••••••••••••••••••••••••••••• 73
DIAGRAMS
....................................................
LIST OF TABLES
75
Table
Page
1Performance Specifications.............................. 1
2 Reliability and Maintenance............................. 2
3 Minimum Read Output Level Requirements.................. 3
4Drive
Selection......................................... 7
5 I/O Signal Connector PI Requirements for aFlat Cable ••• 13
6 I/O Signal Connector PI Requirements for Twisted........ 14
Wire Pairs
7
I/O Signal Connector Pl/J1 Pin Assignments •••••••••••••• 14
8 DC Power Connector P5/J5 Requirements................... 15
9 DC Power Connector P5/J5 Pin Assignments................ 15
10 Installation Requirements............................... 19
11 Factory Configuration of the Customer Strappable •••••••• 21
Options
12 Programmable Shunt Trace/Cut Functions •••••••••••••••••• 23
13 Drive Select Options.................................... 24
14 Side Select Options •••••••••••••••••••.••••••••••••••••• 26
15 Preventi ve Ma intenance Summary.......................... 32
16 Recommended Spare Parts ••••••••••••••••••••••••••••••••• 73
v

vi
LIST OF ILLUSTRATIONS
Figure Page
1 Recommended Controller Interface Circuit................ 5
2
Interface Connections................................... 6
3Step
Timing............................................. 8
4Write
Data Timing for Frequency Modulation (FM)......... 8
5Write
Data Timing for Modified Frequency................ 8
Modulation
(MFM)
6Index Timing •••••••••••••••••••••••••••••••••••••••••••• 10
7 Read Data Timing for Frequency Modulation (FM).......... 11
8 Read Data Timing for Modified Frequency ••••••••••••••••• 11
Modulation (MFM)
9 Track Access Timing ••••••••••••••••••••••••••••••••••••• 12
10 Read Timing •••••••.••.•••••••••••••••••••••••••••••••••• 12
11 Write Timing •••••••••••••••••••••••••••••••••••••••••••• 12
12 Interface Connection •••••••••••••••••••••••••••••••••••• 13
13 Connector Jl Dimensions (Compon~nt Side)................ 13
14
QumeTrak 242 (Top View) •••••••••••.••••••••••••••••••••• 18
15 QumeTrak 242 (Side View) •••••••••••••••••••••••••••••••• 18
16 Disk Drive Mounting ••••••••••••••••••••••••••••••••••••• 18
17 PCB Option Features ••••••••••••••••••••••••••••••••••••• 22
18 Disk Change Timing •••••••••••••.•••••••••••••••••••••••• 28
19a QumeTrak 242 Parts Locations (Top View)................. 30
19b QumeTrak 242 Parts Locations (Bottom View) •••••••••••••• 31
20 R/W Head Radial Positioning ("Cat-eyes")................ 37
21 Azimuth Check ••••••••••••••••••••••••••••••••••••••••••• 39
22 Track 00 Sensor Assembly Removal and Installation ••••••• 42
23 Write Protect/Motor On Sensor Assembly Removal •••.•••••• 44
and Installation
24 Head Load Solenoid Assembly Removal and Installation.... 46
25 Door Lock Solenoid Assembly Removal and Installation •••• 48
26 Index Lamp Assembly Removal and Installation............ 50
27 Index Sensor Assembly Removal and Installation.......... 51
28 Head Carriage Assembly Removal and Installation ••••••••• 55
29 Not Ready Troubleshooting Flowchart Routine ••••••••••••• 61
30 Seek Error Troubleshooting Flowchart Routine............ 63
31 Read Error Troubleshooting Flowchart Routine ••.•.••••••• 66
32 Write 'Error Troubleshooting Flowchart Routine........... 69
33 No Head Load Troubleshooting Flowchart Routine .••••••••• 72
34 QumeTrak 242 Interconnect Diagram ••.•••••••••••••••••••• 77
35 QumeTrak 242 Main PCB Schematic Diagram •••••••.••••••••• 79
36 QumeTrak 242 Drive Motor Control PCB Schematic Diagram.. 83

•
•
•
INTRODUCTION
SCOPE OF MANUAL
The scope of this manual is to provide maintenance information to support the
QumeTrak 242 flexable disk drive in the field. The manual is divided into the
following sections: Introduction,
Interface, Installation, Customer Strap-
pable Options, Maintenance, Troubleshooting,
Recommended Spare Parts, and
Diagrams.
GENERAL DESCRIPTION
The QumeTrak 242 flexible disk drive offers low cost, direct access data
storage, utilizing a removable eight-inch IBM diskette or equivalent as
storage medium
---------NOTE -------- .........
In this manual the medium will be referred to
as simply adisk.
It is compatible with the following IBM disk drives and systems:
Single sided IBM 3740 and System 32 drives: 33FD.
Two sided IBM 3600 and 4964 drives: 43FD.
Two sided double density IBM System 34 drives: 53FD.
The QumeTrak 242 provides astorage capacity of 0.56M bytes on atwo-sided
single density
flexible disk (IBM DISKETTE 2or equivalent), and 1.2M bytes on
atwo-sided double density flexible disk (IBM DISKETTE 20 or equivalent).
The QumeTrak 242 uses atwo-sided head carriage assembly containing two
ceramic read/write tunnel erase heads, and aflexured mounting arrangement for
extremely high reliability.
Fast access time (3ms track-to-track) is accomplished by aprecision steel
belt drive mechanism that affords minimal wear with low power dissipation.
Standard features include:
•
•
•
•
•
Positive DC power required only (no negative DC or AC)
Four drive daisy chain capability
ISO write protect
Program controlled door lock
In Use LED activity indicator on the front panel
1

INTRODUCTION
SPECIFICATIONS SUMMARY
Table 1. Performance Specifications
SPECIFICATION SINGLE DENSITY DOUBLE DENSITY
CAPACITY
PER DISK
UNFORMATTED 0.8M bytes 1.6M bytes
IBM FORMAT 0.56M
bytes
1.2M bytes
RECORDING DENSITY 3408 BPI 6816 BPI
(TRACK NO.
76)
TRACK DENSITY
48 TPI
48 TPI
NUMBER OF CYLINDERS 77 77
NUMBER OF TRACKS 154 154
RECORDING METHOD
FM
MFM
ROTATIONAL SPEED
360 RPM 360 RPM
TRANSFER RATE 250K bits/sec 500K bits/sec
LATENCY (AVERAGE)
83 ms 83 ms
ACCESS TIME
AVERAGE
91 ms
91 ms
TRACK-
TO- TRACK 3ms 3ms
SETTLING 15 ms
15 ms
HEAD LOAD TIME SOms SOma
MOTOR START TIME 2sec 2sec
Table 2. Reliability and Maintenance
RECOVERABLE READ ONE ERROR PER MTTR 30 MINUTES
ERROR RATE 109BITS READ
ERROR NON-RECOVERABLE ONE ERROR
PER PREVENTATIVE 6000 POWER ON HOURS
RATE READ ERROR RATE 1012 BITS READ MAINTENANCE
OR 2YEARS
SEEK ERROR RATE ONE ERROR
PER DESIGN 15000 POWER ON HOURS
106SEEKS LIFE
OR 5YEARS
MTBF 8500 HOURS AT 100% DUTY CYCLE MEDIA 3.5 x106
13000 HOURS AT 50% DUTY CYCLE L1FE* PASSES/TRACK
*USEFUL MEDIA LIFE IS EXCEEDED WHEN
"HEAD OUTPUT" DROPS TO BELOW 80% OF INITIAL VALUE,
AS MEASURED
BY USING IBM DISKETIE (IBM PIN 1766872).
2

INTRODUCTION
COMPATIBILITY
The QumeTrak 242 uses astandard 8-inch flexible disk (IBM Diskette, PIN
1766872 or equivalent) as the recording medium.
The QumeTrak 242 complies with the physical and electrical characteristics
described below for full compatibility with an IBM system.
Read/Write/Erase Head
The geomet ry of the QumeTrak 242 Read/Wri te/Erase head is equi val ent to the
IBM Read/Write/Erase head.
Read Output Level
The QumeTrak 242 read output level, as measured by the following procedure,
satisfies the requirements listed in the table below.
1. Data is written by the QumeTrak 242 on astandard disk (IBM Diskette P.N
1766872).
2. The read output level from the standard disk is checked between test
points TPIA and TPIB (the integrated outputs of the head preamplifier).
Table 3.
Minimum Read Output Level Requirements
Track Output (all '1 ')
all '1' output
Resolution =x100
all '0'
output
76
150 mV pop
50% MIN.
MIN.
Write Current
IBM compatibility requires a 20% reduction in write current on tracks 44
through 76.
Switch Filter
IBM compatibility requires an increase in the read output resolution on tracks
60 through 76.
TRACK POSITIONING
The QumeTrak 242 pos it ions the R/W head to the center 1i ne of track 40 to
within ±0.04 mm (±0.0016 of an inch). Track 40 positioning accuracy can be
checked by using a Qume CE disk (Q.P.N. 50152-02).
3

INTRODUCTION
INDEX POSITIONING
The QumeTrak 242 Index Sensor allows precise positioning in relation to the
read/write head gap.
The dynami cpos it i ona 1 di fference of the QumeTrak 242 is 500 us ± 500 us,
which can be checked by using a Qume CE disk (Q.P.N. 50152-02).
4

INTERFACE
ELECTRICAl INTERFACE
The QumeTrak 242 has two interface connectors: connector Pl/Jl interfaces
digital I/O signals, and connector P5/J5 interfaces the +5V and +24V DC power
source. Refer to the Interface Connections illustration.
All I/O signal interface lines are TTL compatible and are active (true) when
low.
The QumeTrak 242 uses 7438 NAND buffers (open collector) as line drivers and
7414 Schmi tt trigger inverters as 1i ne receivers. The input of all recei ver
lines in a single drive, and those in the last drive of adaisy chain, must be
terminated in 150 ohms pulled up to +5V.
The illustration below shows the recommended controller interface circuit.
CONTROLLER IIDRIVE 1I IDRIVE 21IDRIVE 4
II \ II II , I II I
l I !I I I +5 V
I I 'I I I
I I I I!
~I Ir II I I
7438 or eqUiValent! I! 7414 II 7414 I
I IL+I I I
I , TTL II TTL I TTL
+s VIIII I!
II I I II
IIIIII
74;4T~r eP-q---4Uiyt--ale-nt-'-l: !Q TId re;-
II7436 II7438 I II 7438
III I I
I 10 Feet Max. I
Figure 1. Recommended Controller Interface Circuit
5

INTERFACE
FROM CONTROLLER IFROM QUMETRAK 242
SIGNAL CONNECTOR (P1/Jl)
SIDE SELECT
14 _
-
_10
2-SIDED *
IN USE *16 _-
-_12 DISK
CHANGE *
HEAD LOAD *18 _-
-_20 INDEX
LOW CURRENT 2 _ -
-22 READY
DRIVE SELECT 126 _-
-
_42
TRACK 00
DRIVE SELECT 228 _-
-_
44
WRITE PROTECT
DRIVE SELECT 330 _-
-_
46
READ DATA
DRIVE SELECT 4
32 _-
-
DIRECTION
34 _
-
STEP 36 _
-
WRITE DATA
38 _
-
WRITE GATE
40 _
4.6, 8, 10,12, 16, 18,24
-
--
-
--
ALTERNATE I/O
SIGNAL RETURNS -
-
DC POWER CONNECTOR (PS/JS)
~24 VDC
24 VRETURN
~S VDC
5 V RETURN
2
5
6
------------------- NOTES: --------------------,
1. *Optional.
2. Signal returns (all odd numbered pins on P1/J1), + 24 Vreturn, +5 V return, and frame
ground must be connected together at the controller.
3. Pins 48 and 50 on P1/J1 and Pins 3and 4on P5/J5 are reserved.
Figure 2. Interface Connections
6

INTERFACE
INPUT LINES
There are twelve (12) active low TTL input lines to the QumeTrak 242. Ten
(10) are standard and two (2) are user insta11ab1e options. Individual signal
line characteristics are described below.
High Level:
Low Level:
Impedance:
Drive Select 1-4
Logical False
Logical
True
150 ohms to 5V
2.4 to 5.25V
o to 0.4V
An active low level on the appropriate line (pin 26, 28, 30, or 32) enables
communicaion between the individual drive and the controller.
When two or more (up to 4) drives are daisy chained, each drive must have a
unique
DRIVE SELECT address. The DRIVE SELECT address is controlled by
jumpers DS1 through DS4. When the two pins of jumper DS1 are connected, that
drive will be activated by an active low signal on the DRIVE SELECT number one
1i nee If the two pi ns of jumper DS2 are connected, that dri ve wi 11 be
activated when DRIVE SELECT line number two is low active. The same system
applies to
jumpers DS3 and DS4.
Table 4. Drive Selection
Drive Select Input Jumper Pins
Drive
Number 12 3 4
DS1 DS2 DS3 DS4
1LH H HS000
2HL H H 0S0 0
3HH L H 00S0
4 H H H L 00 0 S
L=low level, H=high level, S=
short,O =open
----------NOTE-----------.
Only one jumper can be connected within a
single drive. Each drive within adaisy
chain must have aunique DRIVE SELECT number.
Direction
DIRECTION (pin 34) defines the direction of read/write head movement. A low
level on this line causes the head positioning mechanism to move the
read/write
head toward the center of the disk when the STEP Line is pulsed.
With the DIRECTION line at ahigh level, apulse on the STEP line causes the
head positioning mechanism to move the read/write head away from the center of
the disk.
The logic state of DIRECTION can be changed at any time after the
trailing (positive going) edge of the STEP pulse, and to within 1microsecond
before the trail ing edge of afollowing STEP pu1 see The logic state of
DIRECTION cannot be changed during the positive going transition of STEP, or
within the preceeding 1microsecond of the positive going transition of STEP.
7

INTERFACE
Step
The negative going edge of a STEP pulse applied to this line (pin 36) will
cause the read/write head to be moved one track. The direction of movement is
controlled by the DIRECTION line. STEP pulses have the timing characteristics
shown below.
Figure
3. Step Timing
Write Data
This interface line (pin 38) provides the data to be written on the disk.
Each transition from high level to an active low level causes the write
current pol ari ty through the head to be reversed. The WRITE DATA timi ng
characteristics for Frequency Modulation (FM) and Modified Frequency
Modulation
(MFM) formats are shown below.
C Clock
DData Bit
Figure 4. Write Data Timing for Frequency Modulation (FM)
I
I
I
150 os min.:
1100 n. max.
I
I
I
I
I ,
C =
CLOCK
D= DATA BIT
Figure 5. Write Data Timing for Modified Frequency Modulation (MFM)
Write Gate
An active low level on this line (pin 40) enables the write current source and
disables the stepping (head movement circuitry. Ahigh level on this line
enables the read circuitry.
Deactivation of DRIVE SELECT and/or changing SIDE SELECT must be delayed at
least 590 us following a write operation, to assure that the track is fully
tunnel erased.
Refer to the READ iIMING and WRITE TIMING diagrams for the timing
relationships.
8

INTERFACE
Side Select
Side Select (pin
14) defines which surface of atwo-sided disk is used for
data recording or retrieval. An active low level on this line selects the R/W
head for side 1(the disk surface that faces the carrier assembly). Ahigh
level
on this line selects the R/W head for side 0of the disk (the disk
surface
that faces the PCB). When switchi ng from si de 0to si de 1 and
conversely, a 100 us delay is required before any read or write operation can
be initiated. Refer to CUSTOMER STRAPPABLE OPTIONS for alternate operation.
low Current ISwitch Filter
When WRITE GATE is low, this signal line (pin 2) should be high on tracks 0
through 43,
and active low on tracks 44 through 76 (low current). When data
is read, this line should be high on tracks 0through 59, and active low on
tracks 60 through 76, in order to improve read output resolution on the inner
tracks (switch
filter).
Head load
An active low level on this optional input line (pin 18), when READY is active
low, causes the R/W head to be loaded against the disk.
Refer to CUSTOMER STRAPPABLE OPTIONS for uses and method of installation.
In Use
An active low level on this optional input line (pin 16) will energize the In
Use LED. Refer to CUSTOMER STRAPPABLE OPTIONS for uses and method of
installation.
OUTPUT LINES
There are seven (7) output lines from the QumeTrak 242; five (5) are standard
and two (2) are optional. Each line has the following properties.
High Level:
Low Level:
Logical
Fal se
Logical
True
2.4 to 5.25V, MAX. leakage current 250
uA when 7438 NAND buffers are at
cutoff.
oto 0.4 V, MAX. sink current 48 rnA
when the 7438 NAND buffers draw
current.
9

INTERFACE
Index
Th is interface signal (pi n20) is provi ded by the dri ve once each
revolution. The leading (negative going) edge of an INDEX pulse indicates to
the controller the beginning of the next track. The timing characteristics
for INDEX are shown below. 1-- 166.7 ms
:!: 2% -
---I
1.8 :!: 0.6 ms
Figure 6. Index Timing
Ready
An active low level on this line (pin 22) indicates that at least three index
pulses have been sensed (two complete disk revolutions by a properly inserted
disk with the door closed). When using a single-sided disk, READY will go
true only when side 0 is selected.
Track 00
An active low level on this line (pin 42) indicates that the R/W head is
positioned at Track 00.
Wri te Protect
An active low level on this line (pin 44) indicates that adisk with an ISO
write protect notch is loaded. Under normal operation, the drive will inhibit
writing when a protected disk is installed in addition to notifying the
co ntro 11 er •
Refer
to CUSTOMER STRAPPABLE OPTIONS for alternate operation.
Read Data
Data from the di sk is output to the host system in the same form as it was
recei ved on the WR ITE DATA 1i ne. Each fl ux reversa 1 that is sensed on the
disk produces a transition to an active low level on the READ DATA line (pin
46) •
10

INTERFACE
LEADING EDGE OF BIT MAYBE ±3500s FROM NOMINAL
5B4-A
Figure 7. Read Data Timing for Frequency Modulation (FM)
--1 I-- 200 :: 50 ns L4.00 I'S Nom.
ill
c0 ,C CDC
C=Leading Edge of Bit Can Be ± 350 ns From Nominal.
0= Leading Edge of Bit Can Be ± 175 ns From Nominal.
Figure 8. Read Data Timing for Modified Frequency Modulation (MFM)
Disk: Change
An active low level on this optional output line (pin 12) indicates that the
disk dri
ve door has been opened and the disk removed after the DR I VE SELECT
signal has gone false. The DISK CHANGE circuit is reset on the true to false
transition of DRIVE SELECT provided that READY is true. Refer to the section
on CUSTOMER STRAPPABLE OPTIONS for method of installation.
Two-Sided
With adisk installed and the drive selected, an active low level on this
optional output line (pin 10) indicates that atwo-sided disk is in use. A
high level indicates that asingle-sided disk is in use. Refer to the section
on CUSTOMER STRAPPABLE OPTIONS for method of installation.
ALTERNATE I/O PINS
Eight alternate I/O pins are provided on connector J1 for interfacing the disk
drive with additional control
signals. These eight alternate I/O pins (4, 6,
8,
10, 12, 16, 18 and 24) connect to PCB pads for customer insta 11 ab 1e
optional jumpers.
Two factory designated input and two factory designated
output lines of the drive interal circuits are selectable by installing
jumpers to I/O pine 10, 12, 16, and 18.
11

INTERFACE
TIMING
The following illustrations (3) indicate the control and data timing require-
ments.
Track Access Timing
s s---, I ~
-j tVvv b:}._m____.,In. .--~ .....
Figure
STEP
Ir---------\~ ...... \ --------.~ S\---------
DC POWER .-.J
--1 ~I:· f---
DRIVE SELECT 1~1 ~
~ ~ S ~ ...... , --------
---f 1--. 0.5 1'. min.
DIRECTION
DC POWER
SIDE SELECT
~. 590 ,.s min.
I
~ f-.. 100 ~S min.
II
-~- :
II
iI
I
STEP
WRITE GATE !I
-j l~i~.S r- '--.J
i ~ .35 ms min. ~--j I1590 iII
r-- 90 ms min. --j I -.., ';;i~.r-- --1 r---
1OO
IJS min.
VALID READ DATA I~I EI I~
Figure 10. Read Timing
DC POWER
STEP
SIDE SELECT
~- 90 ms min. - ~ _I f--.
I . - --, I590 IJS min.
DRIVE SELECT~~~I~---~-----~~----~I~Ir--~-
------l 35 ms min. II --1 r- 590 I'S min. II
----1 r- 100 ,.S min. I
----1t:,L mm ii
WRITE GATE ~ JI l.....-~--
---l ~ 4,.s max.
WRITE DATA -------...;......" QLlL eLL
--+~U---jl - \,,/ - \.J - ~\U---lr - \.J - --
Figure 11. Write Timing
12