LPC47M112_07 SMSC [SMSC Corporation], LPC47M112_07 Datasheet - Page 51

• Manufacturer Part Number: LPC47M112_07
• Description: Enhanced Super I/O Controller with LPC Interface
• Manufacturer: SMSC [SMSC Corporation]

Enhanced Super I/O Controller with LPC Interface
Datasheet
The amount of data which can be handled with a single command to the FDC depends upon MT (multi-track) and N
(number of bytes/sector).
The Multi-Track function (MT) allows the FDC to read data from both sides of the diskette. For a particular cylinder, data
will be transferred starting at Sector 1, Side 0 and completing the last sector of the same track at Side 1.
If the host terminates a read or write operation in the FDC, the ID information in the result phase is dependent upon the
state of the MT bit and EOT byte. Refer to Table 19.
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.
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 20 describes the effect of the SK bit on the Read Data command execution and results.
Except where noted in Table 20, the C or R value of the sector address is automatically incremented (see Table 22).
SMSC DS – LPC47M112
VALUE
SK BIT
0
0
MT
0
1
0
1
0
1
DATA ADDRESS
MARK TYPE
ENCOUNTERED
Normal Data
Deleted Data
N
1
1
2
2
3
3
Table 20 - 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 19 - Effects of MT and N Bits
CAPACITY
DATASHEET
00
01
02
03
07
N
..
Table 18 - Sector Sizes
SECTOR
READ?
Yes
Yes
Page 51
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
SECTOR SIZE
FINAL SECTOR READ
Yes
1024 bytes
No
16 Kbytes
128 bytes
256 bytes
512 bytes
RESULTS
FROM DISK
...
DESCRIPTION OF
Normal
termination.
Address not
incremented. Next
sector not
RESULTS
Rev. 02-16-07