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11.14 Initialize Device Parameters (91h)
Com m and Block Output Registers
Register
7
6
Data
-
Feature
-
Sector Count
V
V
Sector Number
-
Cylinder Low
-
Cylinder High
-
Device/Head
1
Command
1
0
Error Register
7
6
5
4
CRC
UNC
0
IDN
0
0
0
0
Table 125 Initialize Device Parameters Command (91h)
The Initialize Device Parameters command enables the host to set the number of sectors per track and the number
of heads minus 1, per cylinder. Words 54-58 in Identify Device Information reflect these parameters.
The parameters remain in effect until following events:
Another Initialize Device Parameters command is received.
The device is powered off.
Soft reset occurs and the Set Feature option of CCh is set instead of 66h.
Output Parameters To The Device
Sector Count
The number of sectors per track. 0 does not mean there are 256 sectors per track, but there is no
sector per track.
H
The number of heads minus 1 per cylinder. The minimum is 0 and the maximum is 15.
Note:
The following conditions needs to be satisfied to avoid invalid number of cylinders beyond FFFFh.
(Total number of user addressable sectors)/((Sector Count)*(H+1)) = < FFFFh
The total number of user addressable sectors is described in Identify Device command.
5
4
3
2
1
-
-
-
-
-
-
-
-
-
-
-
-
V
V
V
V
V
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
1
D
H
H
H
0
1
0
0
0
3
2
1
0
0
ABT T0N
AMN
0
V
0
0
Western Digital Hard Disk Drive OEM Specification
Com m and Block Input Registers
0
Register
7
-
Data
-
-
Error
-
V
Sector Count
-
-
Sector Number
-
-
Cylinder Low
-
-
Cylinder High
-
H
Device/Head
-
1
Status
Status Register
7
6
5
BSY
RDY
DF
DSC DRQ COR
0
V
0
152
6
5
4
3
2
1
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
...See Below ...
4
3
2
1
IDX
ERR
-
-
0
-
V
0
-
-
-
-
-
-
-
0
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