FDC37C665GT_07 SMSC [SMSC Corporation], FDC37C665GT_07 Datasheet - Page 63

• Manufacturer Part Number: FDC37C665GT_07
• Description: High-Performance Multi-Mode Parallel Port Super I/O Floppy Disk Controllers
• Manufacturer: SMSC [SMSC Corporation]

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 0 to
"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.
After reading the ID and Data Fields in each
sector, the FDC checks the CRC bytes. If a
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 25 - 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
MAXIMUM TRANSFER
Table 24 - Effects of MT and N Bits
CAPACITY
SECTOR
READ?
Yes
Yes
Yes
No
63
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 25 describes the effect
of the SK bit on the
execution and results. Except where noted in
Table 25, the C or R value of the sector address
is automatically incremented (see Table 27).
CM BIT OF
ST2 SET?
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
FINAL SECTOR READ
Yes
Yes
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
Read Data command