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7K200 SATA OEM Specification
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14.13 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 ...See Below...
Sector Count V V V V V V V V Sector Count V V V V V V V V
LBA Low V V V V V V V V LBA Low V V V V V V V V
LBA Mid V V V V V V V V LBA Mid V V V V V V V V
LBA High V V V V V V V V LBA High V V V V V V V V
Device - L - - H H H H Device - - - - H H H H
Command 1 1 0 0 1 0 0 R 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 AM
N
BSY RDY DF DSC DRQ COR IDX ERR
V V 0 V 0 V 0 0 0 V 0 V - 0 0 V
Table 68 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.
Output Parameters To The Device
Sector Count
The number of continuous sectors to be transferred. If zero is specified, then 256 sectors
will be transferred.
LBA Low
The sector number of the first sector to be transferred. (L=0)
In LBA mode, this register specifies LBA address bits 0 - 7 to be transferred. (L=1)
LBA High/Mid
The cylinder number of the first sector to be transferred. (L=0)
In LBA mode, this register specifies LBA address bits 8 - 15 (Mid) 16 - 23 (High) to be
transferred. (L=1)
H
The head number of the first sector to be transferred. (L=0)
In LBA mode, this register specifies LBA bits 24-27 to be transferred. (L=1)
R
The retry bit, but this bit is ignored.
Input Parameters From The Device
Sector Count
The number of requested sectors not transferred. This will be zero, unless an
unrecoverable error occurs.
LBA Low
The sector number of the last transferred sector. (L=0)
In LBA mode, this register contains current LBA bits 0 - 7. (L=1)
LBA High/Mid
The cylinder number of the last transferred sector. (L=0)
In LBA mode, this register contains current LBA bits 8 - 15 (Mid), 16 - 23 (High).
(L=1)
H
The head number of the sector to be transferred. (L=0)
In LBA mode, this register contains current LBA bits 24 - 27. (L=1)