FDC37M81x SMSC Corporation, FDC37M81x Datasheet - Page 56

• Manufacturer Part Number: FDC37M81x
• Description: PC98/99 Compliant Enhanced Super I/O Controller
• Manufacturer: SMSC Corporation

Read Deleted Data
This command is the same as the Read Data
command, only it operates on sectors that contain
a Deleted Data Address Mark at the beginning of a
Data Field.
Read A Track
This command is similar to the Read Data
command except that the entire data field is read
continuously from each of the sectors of a track.
Immediately after encountering a pulse on the
nINDEX pin, the FDC starts to read all data fields
on the track as continuous blocks of data without
regard to logical sector numbers. If the FDC 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 FDC compares the ID information read from
each sector with the specified value in the
command
SK BIT
VALUE
0
0
1
1
and
Normal Data
Deleted Data
Normal Data
Deleted Data
DATA ADDRESS
ENCOUNTERED
Table 22 - Skip Bit vs. Read Deleted Data Command
MARK TYPE
sets
SECTOR
the
READ?
Yes
Yes
Yes
No
56
Table 22 describes the effect of the SK bit on the
Read Deleted Data command execution and
results.
Except where noted in Table 22, the C or R value
of the sector address is automatically incremented
(see Table 23).
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
respectively) should always be set to "0".
This command terminates when the EOT specified
number of sectors has not been read. If the FDC
does not find an ID Address Mark on the diskette
after the second occurrence of a pulse on the
nINDEX 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 command.
CM BIT OF
ST2 SET?
Yes
Yes
No
No
RESULTS
DESCRIPTION OF
Address not
incremented. Next
sector not
searched for.
Normal
termination.
Normal
termination. Sector
not read
("skipped").
Normal
termination.
RESULTS