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11.62 Write DMA Ext (35h)
Com m and Block Output Registers
Register
Data Low
Data High
Current
Feature
Previous
Current
Sector Count
Previous
Current
Sector Number
Previous
Current
Cylinder Low
Previous
Current
Cylinder High
Previous
Device/Head
Command
Error Register
7
6
5
CRC
UNC
0
IDN
V
0
0
Table 253 Write DMA Ext Command (35h)
The Write DMA Ext command transfers one or more sectors of data from the host to the device, and then the data is
written to the disk media.
The sectors of data are transferred through the Data Register 16 bits at a time.
The host initializes a slave-DMA channel prior to issuing the command. Data transfers are qualified by DMARQ and
are performed by the slave-DMA channel. The device issues only one interrupt per command to indicate that data
transfer has terminated and status is available.
If an uncorrectable error occurs, the write will be terminated at the failing sector
Output Parameters To The Device
Sector Count Current
Sector Count Previous
Sector Number Current
Sector Number Previous
Cylinder Low Current
Cylinder Low Previous
Cylinder High Current
Cylinder High Previous
7
6
5
4
3
2
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
-
1
-
D
-
-
0
0
1
1
0
1
4
3
2
1
0
ABT
T0N
V
0
V
0
The number of continuous sectors to be transferred low order, bits (7:0).
The number of continuous sectors to be transferred high order bits (15:8). If zero is
specified in the Sector Count register, then 65,536 sectors will be transferred.
LBA (7:0).
LBA (31:24).
LBA (15:8).
LBA (39:32).
LBA (23:16).
LBA (47:40).
Western Digital Hard Disk Drive OEM Specification
Com m and Block Input Registers
1
0
Register
-
-
Data Low
-
-
Data High
-
-
Error
-
-
V
V
Sector Count
V
V
V
V
Sector Number
V
V
V
V
Cylinder Low
V
V
V
V
Cylinder High
V
V
-
-
Device/Head
0
1
Status
0
7
6
AMN
BSY
RDY
0
0
V
289
7
6
5
4
-
-
-
-
-
-
-
-
...See Below ...
HOB=0
-
-
-
-
HOB=1
-
-
-
-
HOB=0
V
V
V
V
HOB=1
V
V
V
V
HOB=0
V
V
V
V
HOB=1
V
V
V
V
HOB=0
V
V
V
V
HOB=1
V
V
V
V
-
-
-
-
...See Below ...
Status Register
5
4
3
2
DF
DSC
DRQ
COR
0
V
-
0
3
2
1
0
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
-
-
-
-
1
0
IDX
ERR
-
V
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