82077AA Datasheet, PDF (22/62 Pages) Intel Corporation – CHMOS SINGLE-CHIP FLOPPY DISK CONTROLLER

82077AA
Phase
Command
Command
Execution
Result
Command
Execution
Result
Command
Command
Result
Command
Result
RW
W
W
W
W
R
R
R
R
R
R
R
R
R
R
W
W
R
R
R
R
R
R
R
W
W
W
R
W
R
D₇
1
0
0
LOCK
0
0
0
0
OW
LOCK
0
Table 5-1 82077AA Command Set (Continued)
D₆
D₅
DIR
0
0
0
0
0
DATA BUS
D₄
D₃
D₂
D₁
D₀
RELATIVE SEEK
0
1
1
1
1
0
0
HDS
DS1
DS0
RCN
DUMPREG
0
1
1
1
0
SRT
0
D₃
EIS
EFIFO
MFM
0
0
0
PCN-Drive 0
PCN-Drive 1
PCN-Drive 2
PCN-Drive 3
HLT
SC EOT
D₂
D₁
POLL
PRETRK
READ ID
0
1
0
0
HUT
D₀
GAP
FIFOTHR
0
1
HDS
DS1
ND
WGATE
0
DS0
ST 0
ST 1
ST 2
C
H
R
N
PERPENDICULAR MODE
0
0
1
0
0
1
0
0
D₃
D₂
D₁
D0
GAP WGATE
LOCK
0
0
1
0
1
0
0
0
0
LOCK
0
0
0
0
INVALID
Invalid Codes
ST 0
Remarks
Note
Registers placed in FIFO
Commands
The first correct ID
information on the Cylinder
is stored in Data Register
Status information after
Command execution
Disk status after the
Command has completed
Command Codes
Command Code
Invalid Command Codes
(NoOp 82077AA goes
into Standby State)
ST 0 e 80H
SC is returned if the last command that was issued was the FORMAT command EOT is returned if the last command was a
READ or WRITE
NOTE
These bits are used internally only They are not reflected in the Drive Select pins It is the users responsibility to maintain
correspondence between these bits and the Drive Select pins (DOR)
PARAMETER ABBREVIATIONS
Symbol Description
C
Cylinder address The currently select-
ed cylinder address 0 to 255
D₀ D₁
D₂ D₃
Drive Select 0-3 Designates which
drives are Perpendicular drives a ‘‘1’’
indicating Perpendicular drive
Symbol
D
DIR
Description
Data pattern The pattern to be written in
each sector data field during formatting
Direction control If this bit is 0 then the
head will step out from the spindle during
a relative seek If set to a 1 the head will
step in toward the spindle
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