82091AA Datasheet, PDF (151/204 Pages) Intel Corporation – ADVANCED INTEGRATED PERIPHERAL (AIP)

82091AA
8 5 2 6 Format Track
The FORMAT TRACK Command allows an entire
track to be formatted After a pulse from the
INDEX 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 (MFM) The
particular values 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 sec-
tor 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 num-
ber) 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 ad-
dresses (inter-leaving) This incrementing and for-
matting continues for the whole track until the FDC
encounters a pulse on the INDEX pin again and it
terminates the command
Table 31 contains typical values for gap fields that
are dependent on the size of the sector and the
number of sectors on each track Actual values can
vary due to drive electronics
Drive Form
5 25
35
Table 31 Typical PC AT Values for Formatting
MEDIA
Sector Size
N
SC
1 2 MB
512
02
0F
360 KB
512
02
09
2 88 MB
512
02
24
1 44 MB
512
02
18
720 KB
512
02
09
GPL1
2A
2A
38
1B
1B
GPL2
50
50
53
54
54
NOTES
1 All values are in hex except sector size
2 Gap3 is programmable during reads writes and formats
3 GPL1esuggested Gap3 values in read and write commands to avoid splice point between data field and ID field of
contiguous sections
4 GPL2esuggested Gap3 value in FORMAT TRACK Command
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