FDC37M60X SMSC Corporation, FDC37M60X Datasheet - Page 53

• Manufacturer Part Number: FDC37M60X
• Description: ENHANCED SUPER I/O CONTROLLER WITH INFRARED SUPPORT
• Manufacturer: SMSC Corporation

then the head settling time may be saved
between subsequent reads.
If the FDC detects a pulse on the nINDEX pin
twice without finding the specified sector
(meaning that the diskette's index hole passes
through index detect logic in the drive twice), the
FDC sets the IC code in Status Register
"01" indicating abnormal termination, sets the
ND bit in Status Register 1 to "1" indicating a
sector not found, and terminates the Read Data
Command.
VALUE
SK BIT
0
0
1
1
MT
0
1
0
1
0
1
Normal Data
Deleted Data
Normal Data
Deleted Data
DATA ADDRESS
ENCOUNTERED
N
1
1
2
2
3
3
MARK TYPE
Table 23 - Skip Bit vs Read Data Command
256 x 26 = 6,656
256 x 52 = 13,312
512 x 15 = 7,680
512 x 30 = 15,360
1024 x 8 = 8,192
1024 x 16 = 16,384
Table 22 - Effects of MT and N Bits
MAXIMUM TRANSFER
CAPACITY
0 to
SECTOR
READ?
Yes
Yes
Yes
No
53
After reading the ID and Data Fields in each
sector, the FDC checks the CRC bytes. If a
CRC error occurs in the ID or data field, the
FDC sets the IC code in Status Register 0 to
"01" indicating abnormal termination, sets the
DE bit flag in Status Register 1 to "1", sets the
DD bit in Status Register 2 to "1" if CRC is
incorrect in the ID field, and terminates the Read
Data Command. Table 23 describes the effect
of the SK bit on the Read Data command
execution and results. Except where noted in
Table 23, the C or R value of the sector address
is automatically incremented (see Table 25).
CM BIT OF
26 at side 0 or 1
26 at side 1
15 at side 0 or 1
15 at side 1
8 at side 0 or 1
16 at side 1
ST2 SET?
Yes
Yes
FINAL SECTOR READ
No
No
RESULTS
FROM DISK
Normal termination.
Address not
incremented. Next
sector not searched
for.
Normal termination.
Normal termination.
Sector not read
("skipped").
DESCRIPTION OF
RESULTS