Deskstar 7K160 Hard Disk Drive Specification
170
12.16 Read DMA Ext (25h)
Table 95: Read DMA Ext Command (25h)
The Read DMA command reads one or more sectors of data from disk media, 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 indi-
cate that data transfer has terminated and status is available.
If an uncorrectable error occurs, the read will be terminated at the failing sector.
Output parameters to the device
Sector Count Current
The number of sectors to be transferred low order, bits (7:0).
Sector Count Previous
The number of sectors to be transferred high order, bits (15:8). If 0000h in the
Sector Count register is specified, then 65,536 sectors will be transferred.
Sector Number Current
LBA (7:0)
Sector Number Previous
LBA (31:24)
Cylinder Low Current
LBA (15:8)
Cylinder Low Previous
LBA (39:32)
Command Block Output Registers
Command Block Input Registers
Register
7 6 5 4 3 2 1 0
Register
7 6 5 4 3 2 1 0
Data Low
- - - - - - - -
Data Low
- - - - - - - -
Data High
- - - - - - - -
Data High
- - - - - - - -
Feature
Current
- - - - - - - -
Error see
below
Previous
- - - - - - - -
Sector
Count
Current
V V V V V V V V
Sector
Count
HOB=0
- - - - - - - -
Previous
V V V V V V V V
HOB=1
- - - - - - - -
Sector
Number
Current
V V V V V V V V
Sector
Number
HOB=0
V V V V V V V V
Previous
V V V V V V V V
HOB=1
V V V V V V V V
Cylinder
Low
Current
V V V V V V V V
Cylinder
Low
HOB=0
V V V V V V V V
Previous
V V V V V V V V
HOB=1
V V V V V V V V
Cylinder
High
Current
V V V V V V V V
Cylinder
High
HOB=0
V V V V V V V V
Previous
V V V V V V V V
HOB=1
V V V V V V V V
Device/Head
1 1 1 0 - - - -
Device/Head
- - - - - - - -
Command
0 0 1 0 0 1 0 1
Status
See below ...
Error Register
Status Register
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
CRC
UNC
0
IDN
0
ABT
T0N
AMN
BSY RDY
DF
DSC
DRQ
COR IDX
ERR
V
Vs
0
V
0
V
0
0
0
V
0
V
-
0
-
V
Содержание Deskstar 7K160
Страница 2: ......
Страница 18: ...Deskstar 7K160 Hard Disk Drive Specification 4 ...
Страница 20: ...Deskstar 7K160 Hard Disk Drive Specification 6 ...
Страница 21: ...Deskstar 7K160 Hard Disk Drive specification 7 Part 1 Functional specification ...
Страница 22: ...Deskstar 7K160 Hard Disk Drive Specification 8 ...
Страница 24: ...Deskstar 7K160 Hard Disk Drive Specification 10 ...
Страница 34: ...Deskstar 7K160 Hard Disk Drive Specification 20 ...
Страница 55: ...Deskstar 7K160 Hard Disk Drive Specification 41 Part 2 Interface specification ...
Страница 56: ...Deskstar 7K160 Hard Disk Drive Specification 42 ...
Страница 78: ...Deskstar 7K160 Hard Disk Drive Specification 64 ...
Страница 80: ...Deskstar 7K160 Hard Disk Drive Specification 66 ...
Страница 88: ...Deskstar 7K160 Hard Disk Drive Specification 74 ...
Страница 140: ...Deskstar 7K160 Hard Disk Drive Specification 126 ...
Страница 146: ...Deskstar 7K160 Hard Disk Drive Specification 132 ...
Страница 288: ...Deskstar 7K160 Hard Disk Drive Specification 274 ...
Страница 297: ...Write Buffer 249 Write cache function 93 Write Continuous bit 102 Write DRQ interval time 30 ...