Table 94 Read Dma Ext Command (25H); Read Dma Ext (25H) - Hitachi HDS723020BLA642 Specifications
3.5 inch serial ata hard disk drive
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- Datasheet (2 pages) ,
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11.16 Read DMA Ext (25h)
Command 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
Vs
0
Table 94 Read DMA Ext Command (25h)
The Read DMA command reads one or more sectors of data from disk media, and then transfers the data from
the device to the host.
The sectors are transferred through the Data Register 16 bits at a time.
The host initializes a slave-DMA channel prior to issuing the command. The 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 read will be terminated at the failing sector.
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
1
1
D
-
-
0
0
1
0
0
1
4
3
2
1
0
ABT
T0N
V
0
V
0
Hitachi hard disk drive specifications
Command Block Input Registers
1
0
Register
-
-
Data Low
-
-
Data High
-
-
Error
-
-
V
V
HOB=0
Sector Count
V
V
HOB=1
V
V
HOB=0
Sector
Number
V
V
HOB=1
V
V
HOB=0
Cylinder Low
V
V
HOB=1
V
V
HOB=0
Cylinder High
V
V
HOB=1
-
-
Device/Head
0
1
Status
0
7
6
AMN
BSY
RDY
0
0
V
144
7
6
5
4
3
-
-
-
-
-
-
-
-
-
-
...See Below...
-
-
-
-
-
-
-
-
-
-
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
-
-
-
-
-
...See Below...
Status Register
5
4
3
2
DF
DSC DRQ COR
0
V
-
0
2
1
0
-
-
-
-
-
-
-
-
-
-
-
-
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
-
-
-
1
0
IDX
ERR
-
V
- Quick Links:
- Table 1 Type and Model
- General Features
- Data Sheet
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