Fujitsu MHY2250BH User Manual

C141-E262 

5-181 

DMA data-in commands include the following commands: 

• 

READ DMA (EXT) 

• 

IDENTFY DEVICE DMA 

• 

READ LOG DMA EXT 

The DMA mechanism transfers data of more than one block from the device to 
the host.  The completion of a command is reported by an interruption. 

An outline of this protocol is as follows: 

1)  The device receives a DMA data-in 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 send data, it sends the Data FIS to the host. 

4)  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 sent by the device, this protocol is repeated starting from step 3).  (The 
maximum data size is 8 KB.) 

 

RegHD

DATA

RegDH