LPC47M142-NC Standard Microsystems (SMSC), LPC47M142-NC Datasheet - Page 54

• Manufacturer Part Number: LPC47M142-NC
• Manufacturer: Standard Microsystems (SMSC)

Specifications of LPC47M142-NC

• Lead Free Status / RoHS Status: Not Compliant

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).
formatting continues for the whole track until the FDC encounters a pulse on the nINDEX pin again and it terminates the
command.
Table 25 contains typical values for gap fields that are dependent upon the size of the sector and the number of sectors
on each track. Actual values can vary due to drive electronics.
SMSC DS – LPC47M14X
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
3x
IDAM
IDAM
PERPENDICULAR FORMAT
IDAM
FE
FE
FE
FORMAT FIELDS
C
C
C
Y
L
Y
L
Y
L
H
D
H
D
H
D
Page 54
S
E
C
S
E
C
S
E
C
N
O
N
O
N
O
C
R
C
C
R
C
C
R
C
GAP2
GAP2
GAP2
22x
11x
41x
4E
FF
4E
SYNC
SYNC
SYNC
12x
12x
00
00
00
6x
A1
A1
3x
3x
DATA
DATA
DATA
FB or
AM
AM
AM
F8
FB
FB
F8
F8
DATA
DATA
DATA
C
R
C
C
R
C
C
R
C
This incrementing and
GAP3 GAP 4b
GAP3 GAP 4b
GAP3 GAP 4b
Rev. 05/02/2000