FDC37C78-HT Standard Microsystems (SMSC), FDC37C78-HT Datasheet - Page 45

• Manufacturer Part Number: FDC37C78-HT
• Manufacturer: Standard Microsystems (SMSC)

Specifications of FDC37C78-HT

• Package Type: TQFP
• Lead Free Status / RoHS Status: Compliant

At the completion of the Read Data command, the
head is not unloaded until after the Head Unload
Time Interval (specified in the Specify command)
has elapsed. If the host issues another command
before the head unloads, 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 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.
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 22 - 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 21 - Effects of MT and N Bits
CAPACITY
SECTOR
READ?
Yes
Yes
Yes
No
45
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
Command. Table 22 describes the effect of the
SK bit on the Read 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 24).
CM BIT OF
ST2 SET?
field,
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
and
FROM DISK
Normal
termination.
Address not
incremented. Next
sector not
searched for.
Normal
termination.
Normal
termination. Sector
not read
("skipped").
DESCRIPTION OF
terminates
RESULTS
the
Read
Data