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12.64 Write DMA (CAh/CBh)
The Write DMA command transfers one or more sectors of data from the host to the device, then the data is written
to the disk media.
The sectors of data are transferred through the Data Register 16 bits at a time.
The host initializes a slave-DMA channel prior to issuing the command. 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 write will be terminated at the failing sector
Table 253 Write DMA Command (CAh/CBh)
Command Input
Field
Description
FEATURE
N/A
COUNT
The number of logical sectors to be transferred. A value of 00h
indicates that 256 logical sectors are to be transferred
LBA
LBA of first logical sector to be transferred
DEVICE
Bit Description
7:5 Obsolete
4 Transport Dependent
3:0 Reserved
Command
7:0 CAh or CBh
Normal Outputs
See Normal Outputs in Section 12.7 Flush Cache (E7h)
Error Outputs
Field
Description
ERROR
Bit Description
7 INTERFACE CRC bit
6:5 Obsolete
4 ID NOT FOUND bit
3 Obsolete
2 ABORT bit
1:0 Obsolete
COUNT
N/A
LBA
LBA of First Unrecoverable Error
DEVICE
Bit Description
7 Obsolete
6 N/A
5 Obsolete
4 Transport Dependent
3:0 Reserved
STATUS
Bit Description
7:6 Transport Dependent
5 DEVICE FAULT bit
4 N/A
3 Transport Dependent
2 N/A
1 SENSE DATA AVAILABLE bit
0 ERROR bit
330
Hard Disk Drive Specification