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5.4 Command Protocol
C141-E203-01EN 5-147
5.4.5 DMA data-out command protocol
The DMA data-out command is the following command:
• WRITE DMA (EXT) (FUA EXT)
The DMA mechanism transfers data of more than one block from the host to the
device. The completion of the command is reported by an interruption.
An outline of this protocol is as follows:
1) The device receives the DMA data-out command with the Register HD FIS.
2) If an error remaining in the device prevents command execution, the device
sends the Register DH FIS with 1 set in the I bit.
3) When the device is ready to receive data, it sends the DMA Activate FIS to the
host.
4) The device receives the Data FIS from the host.
5) When all data has been transferred, the device sends the Register DH FIS
(with 1 set in the I bit) to complete execution of the command. If any data
remains to be received by the device, this protocol is repeated starting from
step 3). (The maximum data size is 8 KB.)
Device
Host
RegHD
DMACT
DATA
RegDH
Figure 5.14 DMA data-out command protocol