PC87332VLJ-5 NSC [National Semiconductor], PC87332VLJ-5 Datasheet - Page 43

• Manufacturer Part Number: PC87332VLJ-5
• Description: PC87332VLJ (3.3V/5V) and PC87332VLJ-5 (5V) (SuperI/OTM III Premium Green) Floppy Disk Controller, Dual UARTs, IEEE1284 Parallel Port, and IDE Interfac
• Manufacturer: NSC [National Semiconductor]

4 0 FDC Command Set Description
4 1 10 Read Deleted Data Command
The Read Deleted Data command reads logical sectors
containing a Deleted Data AM from the selected drive and
makes the data available to the host P This command is
identical to the Read Data command except for the setting
of the CM bit in ST2 and the skipping of sectors The effect
of SK on the Read Deleted Data command is summarized in
Table 4-11 See Table 4-10 for the state of the result bytes
for a Normal Termination of the command
Command Phase
Execution Phase Data read from disk drive is transferred
to system via DMA or Non-DMA modes
Result Phase
4 1 11 Read ID Command
The Read ID command finds the next available Address
Field and returns the ID bytes (track head sector bytes per
sector) to the
transfer during the Execution Phase of this command An
interrupt is generated when the Execution Phase is complet-
ed
The controller first simulates the Motor On time for the se-
lected drive internally The user must turn on the drive motor
directly by enabling the appropriate drive and motor select
disk interface outputs with the Digital Output Register
(DOR) The Read ID command does not perform an implied
seek
IPS
MT
SK
0
0
1
1
MFM
X
P in the Result Phase There is no data
End of Track Sector Number
SK
X
Data Type
Intersector Gap Length
Deleted
Deleted
Drive Head Number
Normal
Normal
Status Register 0
Status Register 1
Status Register 2
Bytes per Sector
Bytes per Sector
Sector Number
Sector Number
Track Number
Track Number
Head Number
Data Length
X
0
TABLE 4-11 SK Effect on the Read Deleted Data Command
1
X
HD
1
Sector Read
DR1
0
N
Y
Y
Y
DR0
0
(Continued)
43
After waiting the Motor On time the controller starts the
Data Separator and waits for the Data Separator to find the
next sector Address Field If an error condition occurs the
IC bits in ST0 are set to Abnormal Termination and the
controller enters the Result Phase Possible errors are
1 The
2 Two index pulses were detected since the search began
Command Phase
Execution Phase Controller reads first ID Field header
bytes it can find and reports these bytes to the system in the
result bytes
Result Phase
4 1 12 Read A Track Command
The Read A Track command reads sectors in physical order
from the selected drive and makes the data available to the
host This command is similar to the Read Data command
with the following exceptions
1 The controller waits for the index pulse before searching
2 A comparison of the sector Address Field ID bytes will be
0
X
there is no disk in the drive the controller hangs up The
writing a byte to the FIFO This puts the controller into the
Result Phase
and no AM has been found If the Address Field AM was
never found the MA bit is set in ST1
for a sector Address Field If the
before the index pulse the command enters the Result
Phase with the IC bits in ST0 set to Abnormal Termina-
tion
performed except for the sector number The internal
sector address is set to 1 and then incremented for each
successive sector read
P must then take the controller out of this hung state by
CM Bit (ST2)
MFM
P aborted the command by writing to the FIFO If
X
1
0
1
0
X
0
Status Register 0
Status Register 1
Status Register 2
Bytes per Sector
Sector Number
Track Number
Head Number
0
X
1
X
No Further Sectors Read
Normal Termination
Sector Skipped
Normal Termination
Description of Results
HD
0
P writes to the FIFO
DR1
1
DR0
0