Fujitsu MHZ2080BJ, Product/Maintenance Manual

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5.4 Command Protocol
5.4.5 DMA data-out command protocol
The DMA data-out command is the following command:
• WRITE DMA (EXT) (FUA EXT)
•
WRITE LOG DMA 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 RegHD FIS.
2) If an error remaining in the device prevents command execution, the device
sends the RegDH FIS with 1 set in the I bit.
3) When the device is ready to receive data, it sends the DMA Active 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 RegDH 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
DMA Active
DATA
RegDH
Figure 5.17 DMA data-out command protocol
C141-E280 5-183