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NOTE

p atterns  an d  a d j u s t  t h e  W r i t e  D a t a  w a v e -
form.  Alt h ough  a  value  cannot  be specified  for
w rite  p r e c ompensation,  T a n do n  s u g g ests  a

value of 125 nanoseconds for systems using

M FM  double density  recording  format .

T M 8 4 8 - 1 E 

a n d  T M 8 4 8 -2 E

drives include a  microprocessor-

controlled buffered seek capa-

bility.  The  controller  ma y  i s sue

step pulses of one microsecond

m inimu m 

w i d t h ,  a n d  f i f t e e n

microseconds minimu m  spacing
between trai l in g  edges. Internal
drive electronics  issue step com-

ma nd s  a t  a 

r a te  of  three

milliseconds.

WRITE GATE

The drive  electronics  ignore  step  pulses when
one of five conditions exists:

W hen  t h i s  s i g n a l  i s  t r u e  ( l o w ) , t h e  w r i t e
e lectronics  are  prepared  for  w r i t i n g  d at a  a n d
the  read  electronics  are  disabled.  This  signal
turns  on  W r i t e  C u r r ent  i n  t h e  s elected  Read/
Write  head.  Data  is  w r i t t e n  u n der  th e  control

of the Composite Write Data and Side Select

input  l i n es.  When  the  W r it e  Gate  l ine  is  false

(high), all  write  electronics are disabled.

When a write  protected  diskette  is  installed  in
a drive, the  write  electronics are disabled, irre-
spective of  the  state  of  the  W r i t e  Gate  or  Side
Select lines.  Wit h  t h e  N P  j u m p e r  i n s t a l l ed,  a
diskette cannot be write  protected.

1.  The  Wr it e  Gate  is  true  (low).

2 .  Th e  D i r e c t io n  S e l ect  i s  f a l s e  ( h i g h ) ,

and the head is positioned at  Track  0.

3. The drive is 

not selected.

4. When trying to 

seek beyond Track 76.

5.  W hen  the  diskette  lever is opened.

NOTE

C hanges of  s t at e  o f  t h e  W r i t e

G ate  l i n e  s h o ul d  o c cu r  b e f o r e
the first  Wr it e  Data  pulse.

CO M P O S ITE WRITE DATA

IN USE

When  the  drive  is  selected,  this  in t er f ace  lin e

p rovides  the  bit  s er ial  C omposite  Wr it e  D a t a

p ulses that  control  th e  swit ching  of  th e  W r i t e
Current  i n  t h e  selected  head.  The  wr i t e  el ec-
t ronics  must  be  conditioned  for  wr i t i n g  by  t h e
Write  Enable  line.

For each high-to-low  transition on  the Compos-

ite  Write  Data  l i ne,  a  flux  ch ange  is  produced

a t  th e  w r i t e  h e a d  g a p .  T h i s  c a u ses  a  fl u x
change to be recorded on the media.

When a double-frequency type encoding tech-

n ique is used in which  data  and  clock  form  th e

c ombined  W r i t e 

D a t a  s i g n a l , i t  i s  r e c o m -

mended that  th e  r epeti t ion  of  th e  h i g h -to-low
transitions, while  wr i t i n g  all  zeros, be equal to
t he nominal  data  r a te ,  ~ 0 . 1  percent,  and  th e

repetition  of  the  high-to-low  transiti ons, while
writing  all  ones, be equal to  twice  the  nominal

data rate, ~  0.1 percent.

Host controllers  may  implement  wr it e  precom-

pensation  ci r c u it s  t h a t  r e c ognize  w orst  c a se

SIDE SELECT

WRITE CURRENT SWITCH

This strappable  feature  controls  the  lever  lock
solenoid when  the DL  option  is  installed.

Normally,  W r i t e  C u r r ent  s w i t c h in g  i s  a ccom-
p lished  by  t h e  h o s t  c o n t r o l l er.  A  t r u e  ( l o w )
l evel on  t h i s  l i n e  r e duces  the  W r i t e  C u r r e n t .
U sing  o p t i o n  I C ,  t he  dr i v e  a u t o m a t i c a l l y
reduces Write  Current  at  Track  43.

The Side  Select  i n t e r f ace  li ne,  avail able  only
on Tandon's  TM 848-2E,  defines  which  side  of
a  two-sided  d i sk ett e  i s  u s e d  f o r  r e a d in g  o r
w riti ng .  A n 

o p e n  c i r c u i t ,  f a l s e  ( h i g h )  l e v e l

3-4

Summary of Contents for TM848-1E

Page 1: ...TN84 5 i 48 2E FLEXISLK 9I8g j RIVES MJ 4 il PRODUCT SPE IFICATION AND USER S MANUAL...

Page 2: ...en approval of Tandon Corporation This document isintended to provide the user with detailed information adequate for the efficient installation operation and service of the equipment involved However...

Page 3: ...E TM848 2E THINLINE FLEXIBLE DISK DRIVE 48 TRACKS PER INCH PRODUCT SPECIFICATION AND USER S MANUAL lcllld D I 1CORPORATION CHATSWORTH CALIFORNIA 91311 20320 PRAIRIE STREET o COPYRIGHT 1983 TANDON CORP...

Page 4: ...ns Reliability Specifications Environmental Specifications 2 1 2 1 2 1 2 1 2 1 3 4 3 1 3 2 3 3 2 1 2 2 2 3 2 4 SECTION 3 OPER ATION Introduction Unpacking The Drive Preinstallation Checkout Mounting T...

Page 5: ...aracteristics Control and Data Timing Requirements LSI Circuit Board Assembly Non LSI Circuit Board Assembly Recording Media Diskette Care and Handling 1 4 2 2 2 5 2 5 3 6 3 7 3 11 3 12 3 17 3 18 3 1...

Page 6: ...a t a s t o rage The M o del TM848 2E drive doubles data storage capabili ties by using both sides of the diskette 1 1 SCOPE OF THE DOCUMENT 1 3 MA JOR FEATURES MICROPROCESSOR CONTROL The TM848 1E an...

Page 7: ...i v ates t h e cone clamp system r esulting in acc u r ate centering and clamping of the diskette to the drive hub The drive hub is driven at a con s tant s peed o f 360 RPM by a cry st a l controlled...

Page 8: ...n fr o m Track 0 or Tr a c k 0 sensor is always equal to zero The spindle is rotated by a direct drive brush less D C motor with an integral tachometer T he cr y stal controlled s e rv o c i r cuit an...

Page 9: ...GURp y y OISK Qp yp...

Page 10: ...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 re...

Page 11: ...19 0 MM 1 60 40 6 MM 25 4 MM 7 50 190 5 MM 1 650 41 5 MM 0 52 13 2 MM 8 550 217 2 MM 2 025 51 4 MM 2 300 58 4 MM NOTES 1 DIMENSIONS ARE GIVEN IN INCHES METRIC EQUIVALENTS ARE IN PARENTHESES 2 TOLERANC...

Page 12: ...ilinches 51 50 millimeters 2 03 inches 49 42 millimeters 1 95 inches Both Drives TM848 2E Side 1 91 75 millimeters 3 61 inches 89 64 millimeters 3 53 inches 15 000 media contact hours Head Life Disk R...

Page 13: ...percent at 700 milliamperes typical For surge current requirements see Figures 2 2 and 2 3 5 volts 5 percent at 450 milliamperes typical 5 volts D C Power Typical Current Requirements For 24 volts D C...

Page 14: ...FIGURE 2 2 24 VOLT D C CURRENT CONFIGURATION 1 Configured for stepper motor disabled until motor comes up to speed 1 8 amps typical surge STEPPER MOTOR ENABLED C 2 5 U R 2 0 1 5 E N 10 T 0 5 I N 50 10...

Page 15: ...t s One in 10 seeks 10 000 power on hours 30 minutes Mean Time Between Failures Mean Time To Repair TABLE 2 3 ENVIRONMENTAL SPECIFICATIONS Temperature 4 4 C to46 C 40 F to 115 F 40 C to 71 C 40 F to 1...

Page 16: ...e upright horizontal or vertical When mounted horizontally the Logic circuit board side of the chassis must be the top side Eight holes areprovided for mounting two on each side and four on the botto...

Page 17: ...r ough the d r i v e nr h eads a n d diskettes 1 Direction 2 Step 3 Write Data 4 Write Gate 5 In Use 6 Side Select TM848 2E only 7 Write Current Switch 8 Head Load 3 4 INTERFACE CONNECTIONS MOTOR ON...

Page 18: ...state of the Direction Select line when a step pulse is issued The motion is toward the center ofthe disk ifthe Direction Select line is in the true low state The direc tion of motion is away from the...

Page 19: ...5 When the diskette lever is opened NOTE C hanges of state of th e W r i t e Gate line should occur before the first Write Data pulse COMPOSITE WRITE DATA IN USE When the drive is selected this interf...

Page 20: ...ad Data and Ready The strappable output sig nals are Disk Change Two Sided and True Ready READY INDEX The Ready interface signal indicates a disk ette has been inserted into the drive Ready w ill not...

Page 21: ...d r ive has gone to a Ready condition 48 milliamperes maximum V F a l se 2 4 volts minimum open microamperes maximum collector at I 250 Figure 3 1 contains the electrical interface characteristics Fig...

Page 22: ...ILLISECONDS MINIMUM 18 MILLISECONDS TRUE READY WRITE GATE 100 MICROSECONDS MINIMUM 9n sgI I I I S E A A NAP E N S I M I NIMUM I SEE NOTE 4 MICROSECONDS MAXIMUM I WRITE DATA 16 MILLISECONDS MINIMUM 50...

Page 23: ...nd option strapping is determined by the different jumper configura tions required for s pecific system applica tions If jumper configurations are changed power should be cycled off and on so the micr...

Page 24: ...ignal High True Motor Control Select Ready True Ready Lever Lock Solenoid In Use Lever Lock Option In Use Latched In Use Not Latched Disk Change Two Sided Diskette Installed Inhibit Write When Write P...

Page 25: ...is controlled by the Drive Select line DS or the Head Load line HL When either line is true low the stepper motor is driven with full power and is ready for a Seek Read or Write operation When either...

Page 26: ...cted via J1 4 Motor Controlselected via J1 6 Motor Controlselected via J1 8 Motor Control selected via J1 24 X OONL U7 OOMOH 4S Ooo DS4 3S OOO DS3 2S Ooo DS2 I S oOO DS I Oo R Oo D Oo S3 OO S2 Oo S I...

Page 27: ...OO 0 MOH 0 0 MDL OWP 0 ONP 4 B 00 0 D S4 3 B 00 0 D S 3 2 B 00 0 D S 2 I B 00 0 D S I 00 R 00 D 00 S3 0 0 S 2 0 0 S I 0 0 D C 0 0 2 S 0 0 T R 00 MC4 00 MC3 00 MC2 00 MC I 0 0 I C 0 0 X C 0 PS tpl LOJ...

Page 28: ...r ue signal t o t h e controller i n dicating t h a t a doub l e sided diskette i s i ns t alled i n dex h ol e t wo i s present This option is factory installed 2S TW O SIDED DISKETTE LEVER LOCK OPTI...

Page 29: ...s allow the user to test some aspects of drive operation without the use of special test equipment The programs allow the user to isolate the problems of the drive The diagnostic mode provides 16 test...

Page 30: ...motor This test seeks the carriage to Track 76 and turns on the spindle motor This test may be used to check index to data burst and azimuth Seek to Track 75 and turn on spindle motor This test seeks...

Page 31: ...icall test the Track 0 sensor Monitor the status of the lever position switch This test is used to check the lever position switch The front panel L E D flashes on and off with th e opening and closin...

Page 32: ...A damaged or contami nated diskette can impair or prevent recovery o f data and can r esult i n d a m age t o t h e Read Write heads Figure 3 5 contains an i l l u stration of the physical configurat...

Page 33: ...OP IS ENCOUNTERED RETURN THE DISKETTE TO ITS JACKET WHEN NOT IN USE DO NOT WRITE ON THE JACKET WITH PEN OR PENCIL USE A F E LT TIPPED PEN KEEP THE DISKETTE AWAY F R O M M A G NETIC FIELDS DISKETTES S...

Page 34: ...a n o n CORPORATE OFFICES 20320 PRAIRIE STREET CHATSWORTH CA 91311 TELEPHONE NO 213 993 6644 TELEX NO 194794 TWX NO 910 494 1721 PRINTED IN U S A P N 179049 001A T5007A 5 83...

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