TABLE 27 - RESULT PHASE TABLE
FINAL SECTOR
ID INFORMATION AT RESULT PHASE
MT
HEAD
TRANSFERRED TO
HOST
C
H
R
N
0
0
Less than EOT
Equal to EOT
Less than EOT
Equal to EOT
Less than EOT
Equal to EOT
Less than EOT
Equal to EOT
NC
NC
NC
NC
NC
NC
LSB
NC
LSB
R + 1
01
NC
NC
NC
NC
NC
NC
NC
NC
C + 1
NC
1
0
1
R + 1
01
C + 1
NC
1
R + 1
01
NC
NC
R + 1
01
C + 1
NC: No Change, the same value as the one at the beginning of command execution.
LSB: Least Significant Bit, the LSB of H is complemented.
Write Data
•
•
•
•
•
Transfer Capacity
EN (End of Cylinder) bit
ND (No Data) bit
Head Load, Unload Time Interval
ID information when the host terminates the
command
After the Write Data command has been issued,
the FDC loads the head (if it is in the unloaded
state), waits the specified head load time if
unloaded (defined in the Specify command), and
begins reading ID fields. When the sector address
read from the diskette matches the sector address
specified in the command, the FDC reads the data
from the host via the FIFO and writes it to the
sector's data field.
•
Definition of DTL when N = 0 and when N
does not = 0
Write Deleted Data
This command is almost the same as the Write
Data command except that a Deleted Data
Address Mark is written at the beginning of the
Data Field instead of the normal Data Address
Mark. This command is typically used to mark a
bad sector containing an error on the floppy disk.
After writing data into the current sector, the FDC
computes the CRC value and writes it into the
CRC field at the end of the sector transfer. The
Sector Number stored in "R" is incremented by
one, and the FDC continues writing to the next
data field. The FDC continues this "Multi-Sector
Write Operation". Upon receipt of a terminal count
signal or if a FIFO over/under run occurs while a
data field is being written, then the remainder of
the data field is filled with zeros. The FDC reads
the ID field of each sector and checks the CRC
bytes. If it detects a CRC error in one of the ID
fields, it sets the IC code in Status Register 0 to
"01" (abnormal termination), sets the DE bit of
Status Register 1 to "1", and terminates the Write
Data command.
Verify
The Verify command is used to verify the data
stored on a disk. This command acts exactly like
a Read Data command except that no data is
transferred to the host. Data is read from the disk
and CRC is computed and checked against the
previously-stored value.
Because data is not transferred to the host, TC
(pin
89) cannot be used to terminate this
The Write Data command operates in much the
same manner as the Read Data command. The
following items are the same. Please refer to the
Read Data Command for details:
command. By setting the EC bit to "1", an implicit
TC will be issued to the FDC. This implicit TC
will occur when the SC value has decremented
to 0 (an SC value of 0 will verify 256 sectors). This
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