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SV35 Series SATA Product Manual, Rev. B
45
4.3.4.3 Write Stream DMA (3Ah)
Protocol: DMA Out
The Write Stream DMA command allows the host to write data using the DMA data transfer protocol. This com-
mand allows for the host to specify to the device that additional actions need to be performed prior to the com-
pletion of the command if the required bits are set.
If the Write Continuous bit is set to 1, the device shall attempt to not stop execution of the command due to
errors. If the WC bit is set to 1 and errors occur in the transfer or writing of the data, the device shall attempt to
continue to transfer the amount of data requested and then provide ending status with the BSY bit cleared to
zero, the SE bit set to 1, the ERR bit cleared to 0. If the WC bit is set to 1 and the Command Completion Time
Limit expires, the device shall stop execution of the command and provide ending status with the BSY bit
cleared to 0, the SE bit clear, the ERR bit set, and report the fact that the Command Completion Time Limit
expired by setting the CCTO bit in the error register. In all cases, the drive shall attempt to transfer the amount
of data requested within the Command Completion Time Limit even if some data transferred is in error.
Additionally, if the F bit is set for a Write Stream command, the drive shall conclude processing for the com-
mand (including flushing it to the media) before posting status.
FEATURES REGISTER FIELD DESCRIPTIONS
WC (Write Continuous)
This bit indicates if Write Continuous mode is enabled.
1 The device shall attempt to not stop execution of the command due to errors. If the WC bit is set to 1
and errors occur in the transfer or writing of data, the device shall attempt to continue to transfer the
amount of data requested, and then provide ending status with the BSY bit cleared to 0, the SE bit set
to 1, and the ERR bit cleared to 0. If the WC bit is set to 1 and the Command COmpletion Time Limit
expires, te device shall stop execution of the command and provide ending status with the BSY bit
cleared to 0, the SE bit clear, the ERR bit set, and report the fact that the Command Completion Time
Limit expired by setting the CCTO bit in the error register to 1. In all cases, the device shall attempt to
transfer the amount of data requested within the Command Completion Time Limit even if some data
transferred is in error.
Register 76543210
Features
Current Ignored WC F Ignored r Ignored
Previous Command Completion Time Limit (7:0)
Sector Count
Current Sector count
Previous
LBA Low, Mid, High
Current LBA
Previous
Device obs LBA obs DEV Reserved
Command 3Ah
Note: The value indicated as Current is the value most recently written to the register. The value indicated as Previous is
the value that was in the register before the most recent write to the register.