lpc47s457-ns Standard Microsystems Corp., lpc47s457-ns Datasheet - Page 53

• Manufacturer Part Number: lpc47s457-ns
• Description: Advanced I/o With X-bus Interface
• Manufacturer: Standard Microsystems Corp.

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.
Table 21 describes the effect of the SK bit on the Read Deleted Data command execution and results.
Except where noted in Table 21, the C or R value of the sector address is automatically incremented (see Table 22).
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 and
sets the ND flag of Status Register 1 to a “1” if there 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.
SMSC DS – LPC47S45x
VALUE
VALUE
SK BIT
SK BIT
1
1
0
0
1
1
Normal Data
Deleted Data
DATA ADDRESS
ENCOUNTERED
Normal Data
Deleted Data
Normal Data
Deleted Data
DATA ADDRESS
ENCOUNTERED
MARK TYPE
MARK TYPE
Table 21 − Skip Bit vs. Read Deleted Data Command
SECTOR
READ?
SECTOR
Yes
READ?
No
Yes
Yes
Yes
No
DATASHEET
CM BIT OF
ST2 SET?
Page 53 of 259
CM BIT OF
ST2 SET?
Yes
No
Yes
Yes
No
No
Normal termination.
Normal termination. Sector not read ("skipped").
Address not incremented. Next sector not
searched for.
Normal termination.
Normal termination. Sector not read ("skipped").
Normal termination.
RESULTS
RESULTS
DESCRIPTION OF RESULTS
DESCRIPTION OF RESULTS
Rev. 04-30-07