Table 92: Read Dma Ext Command (25H) - Hitachi HDT725025VLA380 - Deskstar 0A33423 T7K500 250GB SATA 7200RPM 8MB Cache Hard Drive Specifications

12.16 Read DMA Ext (25h)
Table 93: Read DMA Ext Command (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
Cylinder Current
Previous
High
Device/Head
Command
Error Register
7 6 5
CRC UNC 0 IDN
V Vs 0
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
Sector Count Previous
Sector Number Current
Sector Number Previous
Cylinder Low Current
Cylinder Low Previous
7 6 5 4 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
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 0 - - - -
0 0 1 0 0 1 0 1
4 3 2 1 0
0 ABT T0N AMN
V 0 V 0 0
The number of sectors to be transferred low order, bits (7:0).
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.
LBA (7:0)
LBA (31:24)
LBA (15:8)
LBA (39:32)
Deskstar T7K500 Hard Disk Drive Specification
Command Block Input Registers
Register
Data Low
Data High
Error
HOB=0
Sector
Count
HOB=1
HOB=0
Sector
Number
HOB=1
HOB=0
Cylinder
Low
HOB=1
Cylinder HOB=0
HOB=1
High
Device/Head
Status
Status Register
7 6 5 4
BSY RDY DF DSC DRQ
0 V 0 V
165
7 6 5 4 3 2 1 0
- - - - - - - -
- - - - - - - -
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 V V
V V V V V V V V
V V V V V V V V
- - - - - - - -
See below ...
3 2 1 0
COR IDX ERR
- 0 - V