FDC37C666GT View Datasheet(PDF) - SMSC -> Microchip
Part Name
Description
MFG CO.
FDC37C666GT
SMSC -> Microchip
'FDC37C666GT' PDF : 152 Pages View PDF
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
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 Read Data command
execution and results. Except where noted in
Table 25, the C or R value of the sector address
is automatically incremented (see Table 27).
Table 24 - Effects of MT and N Bits
MT N MAXIMUM TRANSFER FINAL SECTOR READ
CAPACITY
FROM DISK
0 1 256 x 26 = 6,656
1 1 256 x 52 = 13,312
0 2 512 x 15 = 7,680
1 2 512 x 30 = 15,360
0 3 1024 x 8 = 8,192
1 3 1024 x 16 = 16,384
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
SK BIT
VALUE
0
0
1
1
Table 25 - Skip Bit vs Read Data Command
DATA ADDRESS
RESULTS
MARK TYPE
ENCOUNTERED
SECTOR CM BIT OF DESCRIPTION
READ? ST2 SET? OF RESULTS
Normal Data
Yes
No
Normal
termination.
Deleted Data
Yes
Yes
Address not
incremented.
Next sector not
searched for.
Normal Data
Yes
No
Normal
termination.
Deleted Data
No
Yes
Normal
termination.
Sector not read
("skipped").
63
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