21020285 D User’s Guide
Chapter 6 Target Mode Pass-through Commands
Page 6 - 10 Target Selection Data Structure
Target Selection Data Structure
The Target Selection Data Structure is used by the adapter to give the Host
driver information about the transaction requested of the adapter by a SCSI
initiator.
The address of the area reserved by the Host to accommodate the Target
Selection Data Structure, is passed to the RF3880 in the Target Mode Enable
command (described in Chapter 7). The structure has the following format:
To buffer Host operations from Target Mode operations, information destined
for the Target Selection Data Structure is queued by the RF3880, as initiator
selections occur on the SCSI bus. Information from about sixty selections from
initiators can be queued at a time. See Chapter 8 for more information about
the Selection Queue.
Command Identifier
The Command Identifier that labels the Target Mode Enable command is
copied by the adapter into the Target Selection Data Structure when a selection
occurs. The Host driver may use this for verification of the source of the
selection data.
Address
Offset Byte Memory Address
Offset + 0 Offset + 1 Offset + 2 Offset + 3
00H Command Identifier
04H SCSI flags Reserv ed Error Flags
08H Msg Byte Rcd CDB Length Init ID ID Msg Received
0CH Queue Tag Msg Queue Tag ID Reserved
10H SCSI CDB Received
14H SCSI CDB Received
18H SCSI CDB Received
1CH Reserved Semaphore
Table 44: Target Selection Da ta Structure