TYPE III COMMAND WIRTE TRACK
1. NON·IBM FORMATS
Variations in the IBM formats are possible to a limited extent if the following requirements are met: write-splice area, etc. will add more bytes to each gap to achieve proper operation. It is recommended that the IBM format be used for highest system reliability.
FM MFM
* *Byte counts are minimum, except exactly 3 bytes of A 1 must be written.
Floppy Disk Controller Devices
MIN.
READ ENABLE TIMING
+5V ± .25V
NOTE 1 CS MAY BE PERMANENTL Y TIED LOW IF DESIRED INTRa FALlIttG EDGE INDICATES THAT THE COMMAND REGISTER IS WRITIEN TO
ClK
r--250NS----I~
... 1(2MHZ) - - - , ,
DDEN= 1 ...
1 _________ ""'.
WD
~IWM
Twdl
--1 1 r--
Twd2ClK
r--
125~r
(2MHZ) - - - ,
I
(DDEN = 0) ,'-_ _ _ _ _ _ _ _ - - '
WD
L
1 2 5 - 1
Twdl
--.j
WD MUST HAVE RISING EDGE IN FIRST SHADED AREA AND TRAILING EDGE IN SECOND SHADED AREA.
~
Twd2WRITE DATA/CLOCK RELATIONSHIP
WRITE DATA TIMING MISCELLANEOUS TIMING: (Times Double When Clock
=
1MHz)SYMBOL CHARACTERISTIC MIN. TYP. MAX. UNITS
TCD1 Clock Duty (low) 230 250 20000 nsec
TCD2 Clock Duty (high) 200 250 20000 nsec
TSTP Step Pulse Output 2 or 4 ILsec
TDIR Dir Setup to Step 12 ILsec
TMR Master Reset Pulse Width 50 ILsec
TIP Index Pulse Width 10 ILsec
TWF Write Fault Pulse Width 10 ILsec
Floppy Disk Controller Devices
CONDITIONS
See Note 5
± ClK ERROR See Note 5
1-73
iP 5
I I
r--"P--I
w,
I I
1_''1'1' --I ..
~ lI I
1-
'M"--jLJL
~'co,r·
--J 1-
TC02STEP
MISCELLANEOUS TIMING
"FROM STEP RATE TABLE
j V"
J
VIH5 VI ..
NOTES:
1. Pulse width on RAW READ (Pin 27) is normally 100-300 ns. However, pulse may be any width if pulse is entirely within window. If pulse occurs in both windows, then pulse width must be less than 300 ns for MFM at CLK = 2 MHz and 600 ns for FM at 2 MHz. Times double for 1 MHz.
2. A PPL Data Separator is recommended for 8"
MFM.
3. tbc should be 2Jls, nominal in MFM and 4Jls nominal in FM. Times double when CLK = 1 MHz.
4. RCLK may be high or low during RAW READ (Polarity is unimportant).
5. Times double when clock = 1 MHz.
6. Output timing readings are at VOL 0.8v and VOH
=
2.0v.Table 4. STATUS REGISTER SUMMARY
ALL TYPE I READ READ READ WRITE WRITE
BIT COMMANDS ADDRESS SECTOR TRACK SECTOR TRACK
S7 NOT READY NOT READY NOT READY NOT READY NOT READY NOT READY
86 WRITE
a a a
WRITE WRITEPROTECT PROTECT PROTECT
S5 HEAD LOADED
a
RECORD TYPEa
WRITE FAULT WRITE FAULT84 SEEK ERROR RNF RNF
a
RNFa
S3 CRC ERROR CRC ERROR CRC ERROR
a
CRC ERRORa
S2 TRACK
a
LOST DATA LOST DATA LOST DATA LOST DATA LOST DATA81 INDEX PULSE ORO ORO ORO ORO ORO
SO BUSY BUSY BUSY BUSY BUSY BUSY
STATUS FOR TYPE I COMMANDS
BIT NAME MEANING
87 NOT READY This bit when set indicates the drive is not ready. When reset it indicates that the drive is ready. This bit is an inverted copy of the Ready input and logically "ored" with MR.
S6 PROTECTED When set, indicates Write Protect is activated. This bit is an inverted copy of WRPT input.
85 HEAD LOADED When set, it indicates the head is loaded and engaged. This bit is a logical "and" of HLD and HLT signals.
84 SEEK ERROR When set, the desired track was not verified. This bit is reset to
a
when updated.S3 CRC ERROR CRC encountered in 10 field.
82 TRACK 00 When set, indicates Read / Write head is positioned to Track O. This bit is an inverted copy of the TROO input.
81 INDEX When set, indicates index mark detected from drive. This bit is an inverted copy of the IP input.
80 BUSY When set, command is in progress. When reset no command is in progress.
STATUS FOR TYPE II AND III COMMANDS
BIT NAME MEANING
S7 NOT READY This bit when set indicates the drive is not ready. When reset, it indicates that the drive is ready. This bit is an inverted copy of the Ready input and "ORed" with MR.
The Type II and III Commands will not execute unless the drive is ready.
S6 WRITE PROTECT On Read Record: Not Used. On Read Track: Not Used. On any Write: It indicates a Write Protect. This bit is reset when updated.
S5 RECORD TYPE On Read Record: It indicates the record-type code from data field address mark. 1 WRITE FAULT = Deleted Data Mark. 0 = Data Mark. On any Write: It indicates a Write Fault. This
bit is reset when updated.
S4 RECORD NOT When set, it indicates that the desire track, sector, or side were not found. This bit FOUND (RNF) is reset when updated.
S3 CRC ERROR If S4 is set, an error is found in one or more ID fields; otherwise it indicates error in data field. This bit is reset when updated.
S2 LOST DATA When set, it indicates the computer did not respond to DRQ in one byte time. This bit is reset to zero when updated.
S1 DATA REQUEST This bit is a copy of the DRQ output. When set, it indicates the DR is full on a Read Operation or the DR is empty on a Write operation. This bit is reset to zero when updated.
SO BUSY When set, command is under execution. When reset, no command is under execution.
ELECTRICAL CHARACTERISTICS Absolute Maximum Ratings
Voo with respect to Vss(ground): + 15 to -0.3V Voltage to any input with respect to Vss = + 15
to -0.3V
Icc = 60 MA (35 MA nominal)
100 = 15 MA (10 MA nominal) OPERATING CHARACTERISTICS (DC)
CIN & COUT = 15 pF max with all pins grounded except one under test.
Operating temperature = ooe to 700e Storate temperature = -55°e to + 125°C
TA = OOC to 70°C, Voo = + 12V ± .6V, Vss = OV, Vee = + 5V ± .25V
SYMBOL CHARACTERISTIC MIN. MAX. UNITS CONDITIONS
IlL Input Leakage 10 p.A VIN = Voo **
10L Output Leakage 10 p.A VOUT = Voo
V1H Input High Voltage 2.6 V
V1L Input Low Voltage 0.8 V
VOH Output High Voltage 2.8 V 10 = -100J-LA
VOL Output Low Voltage 0.45 V 10 = 1.6mA
Po Power Dissipation 0.6 W
*1792 and 1794 10 = 1.0 rnA
**Leakage conditions are for input pins without internal up resistors. Pins 22, 23, 33,36, and 37 have pull-up resistors.
Floppy Disk Controller Devices 1-75