SCH3112I-NE SMSC [SMSC Corporation], SCH3112I-NE Datasheet - Page 83

• Manufacturer Part Number: SCH3112I-NE
• Description: LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
• Manufacturer: SMSC [SMSC Corporation]

LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
Datasheet
SMSC SCH311X
MT
0
1
HEAD
0
1
0
1
READ A TRACK
This command is similar to the Read Data command except that the entire data field is read
continuously from each of the sectors of a track. Immediately after encountering a pulse on the
nINDEX pin, the FDC starts to read all data fields on the track as continuous blocks of data without
regard to logical sector numbers. If the FDC finds an error in the ID or DATA CRC check bytes, it
continues to read data from the track and sets the appropriate error bits at the end of the command.
The FDC compares the ID information read from each sector with the specified value in the command
and sets the ND flag of Status Register 1 to a “1” if there no comparison. Multi-track or skip operations
are not allowed with this command. The MT and SK bits (bits D7 and D5 of the first command byte
respectively) should always be set to “0”.
This command terminates when the EOT specified number of sectors has not been read. If the FDC
does not find an ID Address Mark on the diskette after the second occurrence of a pulse on the
nINDEX pin, then it sets the IC code in Status Register 0 to “01” (abnormal termination), sets the MA
bit in Status Register 1 to “1”, and terminates the command.
NC: No Change, the same value as the one at the beginning of command execution.
LSB: Least Significant Bit, the LSB of H is complemented.
WRITE DATA
After the Write Data command has been issued, the FDC loads the head (if it is in the unloaded state),
waits the specified head load time if unloaded (defined in the Specify command), and begins reading
ID fields. When the sector address read from the diskette matches the sector address specified in the
command, the FDC reads the data from the host via the FIFO and writes it to the sector’s data field.
After writing data into the current sector, the FDC computes the CRC value and writes it into the CRC
field at the end of the sector transfer. The Sector Number stored in “R” is incremented by one, and
the FDC continues writing to the next data field. The FDC continues this “Multi-Sector Write
Operation”. Upon receipt of a terminal count signal or if a FIFO over/under run occurs while a data
field is being written, then the remainder of the data field is filled with zeros.
field of each sector and checks the CRC bytes. If it detects a CRC error in one of the ID fields, it sets
the IC code in Status Register 0 to “01” (abnormal termination), sets the DE bit of Status Register 1
to “1”, and terminates the Write Data command.
The Write Data command operates in much the same manner as the Read Data command. The
following items are the same. Please refer to the Read Data Command for details:
FINAL SECTOR
TRANSFERRED TO
HOST
Less than EOT
Equal to EOT
Less than EOT
Equal to EOT
Less than EOT
Equal to EOT
Less than EOT
Equal to EOT
Table 7.20 Result Phase
DATASHEET
ID INFORMATION AT RESULT PHASE
C
NC
C + 1
NC
C + 1
NC
NC
NC
C + 1
67
H
NC
NC
NC
NC
NC
LSB
NC
LSB
R
R + 1
01
R + 1
01
R + 1
01
R + 1
01
The FDC reads the ID
Rev 0.2 (09-28-04)
N
NC
NC
NC
NC
NC
NC
NC
NC