FDC37C669_07 SMSC [SMSC Corporation], FDC37C669_07 Datasheet - Page 62

• Manufacturer Part Number: FDC37C669_07
• Description: PC 98/99 Compliant Super I/O Floppy Disk Controller with Infrared Support
• Manufacturer: SMSC [SMSC Corporation]

Format A Track
The Format command allows an entire track to
be formatted. After a pulse from the IDX 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).
GAP4a
GAP4a
GAP4a
80x
40x
80x
4E
FF
4E
SYNC
SYNC
SYNC
12x
12x
00
6x
00
00
C2
C2
3x
3x
IAM
IAM
IAM
FC
FC
FC
GAP1
GAP1
GAP1
50x
26x
50x
4E
FF
4E
SYSTEM 3740 (SINGLE DENSITY) FORMAT
SYSTEM 34 (DOUBLE DENSITY) FORMAT
SYNC
SYNC
SYNC
12x
12x
00
00
00
6x
A1
A1
3x
PERPENDICULAR FORMAT
3x
IDAM
IDAM
IDAM
FE
FE
FE
FORMAT FIELDS
C
Y
C
Y
C
Y
L
L
L
H
D
H
D
H
D
S
E
C
S
E
C
S
E
C
62
N
O
N
O
N
O
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
nonsequential sector addresses (interleaving).
This incrementing and formatting continues for
the whole track until the FDC encounters a pulse
on the IDX 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.
C
R
C
C
R
C
C
R
C
GAP2
GAP2
GAP2
22x
11x
41x
4E
FF
4E
the
SYNC
SYNC
SYNC
12x
12x
00
00
00
6x
disk
A1
A1
3x
3x
DATA
DATA
DATA
FB or
AM
AM
AM
F8
FB
FB
F8
F8
to
DATA
DATA
DATA
be
C
R
C
C
R
C
C
R
C
formatted
GAP3 GAP 4b
GAP3 GAP 4b
GAP3 GAP 4b
with