RS 237-088 Manuale utente
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5.25" Floppy Disk Drive
Stock No. 237-088
1.0 Introduction
1.1 General description
This drive is a high-density, dual speed, double-sided 5.25" mini-floppy disk drive.
The speed is controlled by Pin #2 of the interface connector. Normally, when this pin
is at logical low, the transfer rate is low and when at logical high, the transfer rate is
high. This drive can be used as a high-density 1.6Mb drive. When at logical low,
this drive can be used as a standard 1.0Mb drive.
Table 1-1. Compatibility with other model drives
Read by this drive
Double-sided
48 t.p.i.
Double-sided
96 t.p.i.
Dual-speed
0.5Mb
1.0Mb
1.6Mb
1.0Mb
300 r.p.m.
300 r.p.m.
300 r.p.m.
360 r.p.m.
MD
MD
HD
MD
FDD used Diskette Capacity
360 r.p.m.
300 r.p.m.
360 r.p.m.
300 r.p.m.
360 r.p.m.
360 r.p.m.
360 r.p.m.
300 r.p.m.
360 r.p.m.
360 r.p.m.
Rotational
speed
Rotational
speed Transfer rate
300Kbits/sec
250Kbits/sec
300Kbits/sec
250Kbits/sec
500Kbits/sec
300Kbits/sec
250Kbits/sec
300Kbits/sec
250Kbits/sec
Diskette written
Leaflet No. 9419 26/4/97 6:09 pm Page 1
Key features:
Compact half-height size.
1.0 or 1.6Mb storage capacity (unformatted).
Backward compatibility to 48 t.p.i.
3ms track to track access time.
Brushless dual-speed direct-drive motor.
Low power consumption.
10,000 hours MTBF.
Dual read channels.
250/300/500 Kbits/transfer rate.
1.2 Specification summary
1.2.1 Performance specifications
Mini mode Maxi mode
(Low transfer rate) (High transfer rate)
Capacity (bytes)
Unformatted (MFM)
Per drive 1,000,000 1,666,666/1,604,167
Per surface 500,000 833,333/802,083
Per track 6,250 10,416
Unformatted (FM)
Per drive 500,000 833,333/802,083
Per surface 250,000 416,666/401,041
Per track 3,125 5,208
IBM format (MFM) 16 sectors/track 15 sectors/track
Per drive 655,360 1,228,800/1,182,720
Per surface 327,680 614,400/591,360
Per track 4,096 7,680
Per sector 256 512
IBM format (FM) 16 sectors/track 15 sectors/track
Per drive 327,680 614,400/591,360
Per surface 163,840 307,200/295,680
Per track 2,048 3,840
Per sector 128 256
Transfer rate (Kbits/sec)
MFM recording 250/300 500
FM recording 125/150 250
Access time (ms)
Track to track 3 3
Settle time 15 15
Average access 94 94/91
Average latency 100/83 83
Motor start time 500 500
Motor speed change time 500 500
*IBM is the registered trade mark of International Business Machines; IBM Corp
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1.2.2 Functional specifications
Mini mode Maxi mode
Rotational speed 300 r.p.m. 360 r.p.m.
Recording density (innermost track)
MFM recording 5,922 b.p.i. 9,870/9,642 b.p.i.
FM recording 2,961 b.p.i. 4,935/4,821 b.p.i.
Flux density (innermost track)
MFM recording 5,922 f.c.i. 9,870/9,642 f.c.i.
FM recording 5,922 f.c.i. 9,870/9,642 f.c.i.
Track density 96 t.p.i. 96 t.p.i.
Cylinders 80 80/77
Tracks 160 160/154
Read/write heads 2 2
Encoding method FM/MFM FM/MFM
Media requirements Double sided/double density/ANSI SPEC
1.2.3 Reliability specifications
MTBF 10,000 POH
Component life 15,000 POH or 5 years
Error rates
Soft error rate 1 per 109 bits read
Hard error rate 1 per 1012 bits read
Seek error 1 per 106seeks
Media life
Number of passes per track 3.5 x 106
Number of media clamp 3.0 x 104
1.2.4 Physical specifications
Shipping Storage Operating
Environmental limits
Ambient temperature -40 to 144¡F -8 to 131¡F 41 to 115¡F
(-40 to 62.2¡C) (-22.2 to 55¡C) (5 to 46.1¡C)
Relative humidity 1 to 95% RH 1 to 95% RH 20 to 80% RH
Max. wet bulb temp. No-condensing No-condensing 85¡F(29.4¡C)
Vibration ²5G(5-55Hz) ²5G(5-55Hz) ²0.5G(5-55Hz)
Shock ²40G(10ms) ²40G(10ms) ²0.5G(10ms)
Mechanical dimension: (excluding front plate)
Width = 5.75 ±0.02" (146.0 ±0.5mm)
Height = 1.65" (42.0mm) max.
Depth = 7.95" (202mm) max.
Mechanical dimension: (including front plate)
Width = 5.88 ±0.02" (149.4 ±0.5mm)
Height = 1.63 ±0.02" (41.5 ±0.5mm)
Depth = 8.15" (207.0mm) max.
Weight = 2.21lbs (1kg)
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1.2.5 Power requirements
Note: Calculation method for power consumption:
Our voltage specification is subject to 12V ±10% accordingly, in the case of
calculating the maximum figure, it becomes larger than that of the competitor's by
±5%.
"Stand by mode" states all input signals "off".
Note: 1. At motor start: Up to 500ms after motor start.
2. Seek: For seeking after 500ms subsequent to motor start.
3. Power requirements represent the values in the case where a media with a
media load of 100g/cm is used.
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Item Rating
Power
requirement
Power consumption
12V
5V
Current
Current
During operation
During operation
12V±10% Max ripple 100mVp-p
5V ±5% max. ripple 50mVp-p
0.54A (max.)
0.35A (typ)
Seek
Read 0.27A (max.)
0.22A (typ)
0.35A (max.)
0.28A (typ)
At motor start 0.9A(Max)
0.7A(Typ)
Write
0.41A (max.)
0.34A (typ)
Seek
Read 0.56A (max.)
0.48A (typ)
0.58A (max.)
0.49A (typ.)
Write
Seek
Read
Write
Stand by
9.28W (max.)
5.88W (typ)
6.50W (max.)
5.02W (typ)
7.66W (max.)
5.81W (typ)
2.42W (max.)
1.85W (typ)
Voltage
Voltage
Leaflet No. 9419 26/4/97 6:09 pm Page 4
4. Peak currents are as specified in figures 2-3.
1.3 Functional characteristics
This drive consists of read/write and control electronics, drive mechanism, read/write
heads, and precision track position mechanism. These components perform the
following functions:
a. Interpret and generate control signals.
b. Move read/write heads to the desired track.
c. Read and write data.
The interface signals and their relationship to the internal functions are shown in
figure 1-2.
1.3.1 Read/write control electronics
The electronics package contains:
a. Index detector circuits.
b. Head positioning driver circuits.
c. Read/write amplifier and transition detector.
d. Write protect detector.
e. Drive select circuits.
f. Drive motor control circuits.
g. Control logic LSI.
h. Track ¯ detector.
i. Media detector.
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Power
(W)
4.0
2.0
Stand byReadWriteSeekMotor ON
0.2
0.4
0.6
0.8
Current
(A)
4.0
6.0
8.0
10.0
0
Max. power
consumption
12V current typ
5V current typ
Typ power
Consumption
Figure 1-1. D.C. power profile of power consumption
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j. Low pass filter.
1.3.2 Drive mechanism
The drive motor under servo speed control (using a frequency generator) rotates
the spindle motor at 300 or 360 r.p.m. through a direct-drive system. An expandable
collet/spindle assembly provides precision media positioning to ensure data
interchange.
1.3.3 Positioning mechanics
The read/write head assembly is accurately positioned through the use of a leading
screw which is attached to the head carriage assembly. Precise track location is
accomplished as the head carriage is moved by the precise discrete rotation of a
stepping motor.
1.3.4 Read/write heads
The proprietary heads are single-element ceramic read/write heads with tunnel
erase elements to provide erased areas between the data tracks. Thus, normal
interchange tolerances between media and drives will not degrade the signal-to-
noise ratio and diskette interchangeability is ensured.
The heads are mounted on a carriage which is located on precision guide rods. The
diskette is held on a plane perpendicular to the read/write heads by a plate located
on the base casting. This precise registration assures perfect compliance with the
read/write heads. The read/write heads are in direct contact with the diskette. The
head surface has been designed to obtain maximum signal transfer to and from the
magnetic surface of the diskette with minimum head/diskette wear.
1.3.5 Recording formats
The formats of the data written on the diskette are totally a function of the host
system. The formats can be designed around the user's application (FM or MFM) to
take complete advantage of the total available bits that can be written on any track.
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Leaflet No. 9419 26/4/97 6:09 pm Page 6
2.0 Electrical interface
The following section provides the electrical definition for each line. Figure 2-1
shows all of the interface connections with respect to the host system.
The signal interface consists of the following two categories:
a. Control lines.
b. Data transfer lines.
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In use/spare (option)
Step
Direction Select
Drive select (4 lines)
Track 0
Index
Motor on
Side select
Ready/drive status
Mode select
Write data
Write gate
Write protect
Read data
Write
logic
Read
logic
Control
logic
Index
In use LED
Index
detector
Stepping
motor
¯1
¯1
¯2
¯2
Track 0
detector Track 0
Media
detector
Write
protect
detector
Write
protect
Write head 0
Write head 1
Drive
Motor
Read/write
head
assembly
Read head 0
Read head 1
Frequency
generator
Motor
control
Motor
driver Low/high speed
Motor on
Figure 1-2. Functional diagram
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All lines in the signal interface are digital in nature and provide signals to the drive
(input), or to the host (output), by way of the interface connector J1.
The power connector, J2, provides +5V and +12V power.
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Drive select 1
Drive select 2
Drive select 3
Drive select 4
Motor ON
Direction select
Step
Write data
Write gate
Side select
In use/spare (option)
Mode select
+12V
+12V Return
+5V Return
+5V
1
2
3
4
100kW0.01mF
Signal ground
Frame groundSystem frame ground
J2/P2
Connector
Ground
J1/P1
Connector
2
4
32
24
22
20
18
16
6
14
12
10 8
26
28
30
34
Index
Track 0
Write protect
Read data
Ready/drive status
Figure 2-1. Interface connection
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2.1 Signal interface
This drive uses the industry standard open-collector, low-level - true, multiplexed
interface convention. The industry standard open-collector, 40mA TTL driver 7438
or equivalent, is used to transmit the I/O signals. The transmitted signals are
detected by the hysteresis input inverter, 7414 or equivalent. A 150½ pull-up resistor
between the signal line and +5V is necessary on the receiving circuit. The input of
each receiver is terminated by a 150½ resistor and a diode. When using two or
more drives on a daisy chain, remove all plug jumpers "TM" except for the last drive
on the daisy chain.
The input signal lines which are not multiplexed are MOTOR ON and IN USE. The
input lines have the following electrical specifications. See figure 2-2 for the
recommended circuits.
True = Logical zero = Vin = +0.0 to +0.4V @ Iin = 40mA (max.)
False = Logical zero = Vin = +2.5 to +5.25V @ Iin = 250µA (open)
Input impedance = 150½
2.2 Input lines
There are twelve active low TTL input lines to the drive. Individual signal line
characteristics are described overleaf.
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+5V
TM
Diode
150W
Max. 10 feet
ribbon or
twisted pair
7414
or equivalent
7438
or equivalent
Figure 2-2. Interface signal driver/receiver
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2.2.1 Drive select 1, 2, 3, or 4 (J1 pins #10, 12, 14, and 6)
Four separate input lines, drive select 1, drive select 2, drive select 3, and drive
select 4 are provided so that in standard configuration, up to four drives may be
multiplexed together in a system that have separate drive select lines. Traces DS1,
DS2, DS3, and DS4 have been provided to select which drive select line will activate
the interface signals for a unique drive. Drive select, when activated to logical zero
level, enables the multiplexed I/O lines.
2.2.2 Direction select (J1 pin #18)
"Direction select" determines the direction the head-carriage assembly will move
when the drive is properly selected, and when step pulses with the proper timing are
sent to the drive. If "direction select" is at logic low, the head-carriage assembly will
seek toward the centre of the diskette, and away from the centre when high.
"Direction select" must be stable at its correct logic state for at least 1 microsecond
before each occurance of the trailing edge (a low-to-high transition) of the step
pulse, as measured at the drive interface connector, J1.
If the drive is not selected or a write operation is in process, "direction select" is
ignored by the drive.
2.2.3 Motor on (J1 pin #16)
The "motor on" signal causes the drive's spindle drive motor to turn on. In standard
configuration (jumpers MS open), this input signal line when true (logic low), will
activate the motor if +5V and +12V are applied to the drive, whether or not the
drive is selected. A minimum delay of 500ms must be allowed by the host system
after activating this line before attempting to read or write, to allow the diskette to
attain proper speed.
When the command "motor on" is not active, the spindle drive motor stops in about
4 seconds.
It is recommended that the spindle drive motor should be turned off when the drive
has not been selected for 10 revolutions or more. This will extend motor and
diskette life and decrease power consumption. Host system workload must be
analysed to determine optimum delay between the reselection of the drive and the
turning-off of the spindle drive motor.
Even though the "motor on" signal is active, the spindle drive motor does not turn on,
if the function of the media sensor status is not active.
2.2.4 Step (pin #20)
When the drive is properly selected and the trailing edge (a low-to-high transition) of
the "step" signal occurs, the head-carriage assembly will move one track in the
direction selected by "direction select" (J1 pin 18).
"Step" and its timing are generated by the host system controller.
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Leaflet No. 9419 26/4/97 6:09 pm Page 10
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