LPC47U33X View Datasheet(PDF) - SMSC -> Microchip
Part Name
Description
MFG CO.
LPC47U33X
SMSC -> Microchip
'LPC47U33X' PDF : 252 Pages View PDF
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.
Table 27 - Result Phase
FINAL SECTOR
MT
HEAD TRANSFERRED TO
ID INFORMATION AT RESULT PHASE
HOST
C
H
R
N
0
0
Less than EOT
NC
NC
R+1
NC
Equal to EOT
C+1
NC
01
NC
1
Less than EOT
NC
NC
R+1
NC
Equal to EOT
C+1
NC
01
NC
1
0
Less than EOT
NC
NC
R+1
NC
Equal to EOT
NC
LSB
01
NC
1
Less than EOT
NC
NC
R+1
NC
Equal to EOT
C+1
LSB
01
NC
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. The FDC reads the ID 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.
61
Share Link: 