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13.5.12 Read DMA(C8h/C9h)
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
- - - - - - - -
Data
- - - - - - - -
Feature
- - - - - - - -
Error
Sector Count
V V V V V V V V
Sector Count
V V V V V V V V
Sector Number
V V V V V V V V
Sector Number
V V V V V V V V
Cylinder Low
V V V V V V V V
Cylinder Low
V V V V V V V V
Cylinder High
V V V V V V V V
Cylinder High
V V V V V V V V
Device/Head
1 L 1 D H H H H
Device/Head
- - - - H H H H
Command
1 1 0 0 1 0 0 R
Status
...See Below...
...See Below...
Error Register
7
BBK
6
UNC
5
0
4
IDN
3
0
V
V
0
V
0
Status Register
2
1
0
ABT T0N AMN
V
0
V
7
BSY
6
RDY
5
DF
0
V
0
4
3
DSC DRQ
V
-
2
COR
1
IDX
0
ERR
0
0
V
Figure 87. Read DMA Command (C8h/C9h)
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 indicate that data transfer has terminated and status is available.
If an uncorrectable error occurs, the read will be terminated at the failing sector.
Hard disk drive specification for DSCM-11000/-10512/-10340
103