82077AA Datasheet, PDF (26/62 Pages) Intel Corporation – CHMOS SINGLE-CHIP FLOPPY DISK CONTROLLER

82077AA
Table 5-6 Result Phase Table
MT
Head
Final Sector Transferred
to Host
ID Information at Result Phase
C
H
R
N
0
0
1
Less than EOT
Equal to EOT
Less than EOT
Equal to EOT
NC
NC
R^a1
NC
C^a1
NC
01
NC
NC
NC
R^a1
NC
C^a1
NC
01
NC
0
1
1
Less than EOT
Equal to EOT
Less than EOT
Equal to EOT
NC
NC
R^a1
NC
NC
LSB
01
NC
NC
NC
R^a1
NC
C^a1
LSB
01
NC
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
5 1 3 READ TRACK
This command is similar to the READ DATA com-
mand except that the entire data field is read contin-
uously from each of the sectors of a track Immedi-
ately after encountering a pulse on the IDX pin the
82077AA starts to read all data fields on the track as
continuous blocks of data without regard to logical
sector numbers If the 82077AA finds an error in the
ID or DATA CRC check bytes it continues to read
data from the track and sets the appropriate error
bits at the end of the command The 82077AA com-
pares the ID information read from each sector with
the specified value in the command and sets the
ND flag of Status Register 1 to a ‘‘1’’ if there is no
comparison Multi-track or skip operations are not
allowed with this command The MT and SK bits
(Bits D7 and D5 of the first command byte respec-
tively) should always be set to ‘‘0’’
This command terminates when the EOT specified
number of sectors have been read If the 82077AA
does not find an ID Address Mark on the diskette
after the second occurrence of a pulse on the IDX
pin then it sets the IC code in Status Register 0 to
‘‘01’’ (Abnormal termination) sets the MA bit in
Status Register 1 to ‘‘1’’ and terminates the com-
mand
Sector Number stored in ‘‘R’’ is incremented by one
and the 82077AA continues writing to the next data
field The 82077AA 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 82077AA 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
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
 Transfer Capacity
 EN (End of Cylinder) bit
 ND (No Data) bit
 Head Load Unload Time Interval
 ID information when the host terminates the com-
mand
 Definition of DTL when N ^e 0 and when N does
not ^e 0
5 1 4 WRITE DATA
After the WRITE DATA command has been issued
the 82077AA 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 speci-
fied in the command the 82077AA reads the data
from the host via the FIFO and writes it to the sec-
tor’s data field
After writing data into the current sector the
82077AA computes the CRC value and writes it into
the CRC field at the end of the sector transfer The
5 1 5 WRITE DELETED DATA
This command is almost the same as the WRITE
DATA command except that a Deleted Data Ad-
dress 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 con-
taining an error on the floppy disk
5 1 6 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 trans-
ferred to the host Data is read from the disk CRC
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