LPC47U332 View Datasheet(PDF) - SMSC -> Microchip
Part Name
Description
MFG CO.
LPC47U332
SMSC -> Microchip
'LPC47U332' PDF : 252 Pages View PDF
Format A Track
The Format command allows an entire track to
be formatted. After a pulse from the nINDEX
pin is detected, the FDC starts writing data on
the disk including gaps, address marks, ID
fields, and data fields per the IBM System 34 or
3740 format (MFM or FM respectively). The
particular values that will be written to the gap
and data field are controlled by the values
programmed into N, SC, GPL, and D which are
specified by the host during the command
phase. The data field of the sector is filled with
the data byte specified by D. The ID field for
each sector is supplied by the host; that is, four
data bytes per sector are needed by the FDC for
C, H, R, and N (cylinder, head, sector number
and sector size respectively).
After formatting each sector, the host must send
new values for C, H, R and N to the FDC for the
next sector on the track. The R value (sector
number) is the only value that must be changed
by the host after each sector is formatted. This
allows the disk to be formatted with
nonsequential sector addresses (interleaving).
This incrementing and formatting continues for
the whole track until the FDC encounters a pulse
on the nINDEX pin again and it terminates the
command.
Table 28 contains typical values for gap fields
which are dependent upon the size of the sector
and the number of sectors on each track. Actual
values can vary due to drive electronics.
FORMAT FIELDS
SYSTEM 34 (DOUBLE DENSITY) FORMAT
DATA
GAP4a SYNC IAM GAP1 SYNC IDAM C H S N C GAP2 SYNC AM
C
80x 12x
50x 12x
Y D E O R 22x 12x
DATA R GAP3 GAP 4b
4E 00
4E 00
L C C 4E 00
C
3x FC
C2
3x FE
A1
3x FB
A1 F8
SYSTEM 3740 (SINGLE DENSITY) FORMAT
DATA
GAP4a SYNC IAM GAP1 SYNC IDAM C H S N C GAP2 SYNC AM
C
40x 6x
26x 6x
Y D E O R 11x 6x
DATA R GAP3 GAP 4b
FF 00
FF 00
L C C FF 00
C
FC
FE
FB or
F8
PERPENDICULAR FORMAT
DATA
GAP4a SYNC IAM GAP1 SYNC IDAM C H S N C GAP2 SYNC AM
C
80x 12x
50x 12x
Y D E O R 41x 12x
DATA R GAP3 GAP 4b
4E 00
4E 00
L C C 4E 00
C
3x FC
C2
3x FE
A1
3x FB
A1 F8
63
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