Chapter 6 Target Mode |
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Target Mode Response Command | Page 6 - 17 |
Response Control Flags
Since the adapter, acting as a Target, controls the phases of the SCSI bus, this field is important to use as a means of informing the RF3880 of what actions it should take on the SCSI bus, during which phase. The format is as follows:
BITS
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
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SMB | LSC | DSC | NSC | CMD | BFR | DSD | CSC |
Table 51: Meaning of Response Control Flags Field
CSC Connected SCSI Command - The following conditions will cause the adapter to hold connection to the SCSI bus: disconnects are not allowed by either initiator or Host, ATN was asserted by the initiator, or certain error conditions occurred. To continue processing the nexus for which the bus is held, the Host must send a Target Mode Response command that has this bit set. This Target Mode Response command’s Initiator ID, LUN, and Queue Tag ID fields must exactly match the nexus for which the bus is held. If the SCSI bus is disconnected, this bit is ignored.
0 ⇒ If the SCSI bus is being held, defer execution of this command.
1 ⇒ Execute this command to continue the current SCSI operation.
DSD Disconnect - This bit is used to tell the adapter to disconnect from the SCSI bus after a new command is received as a result of either the CMD bit or LSC bit being set.
0 ⇒ This option will not be used.
1 ⇒ The adapter must disconnect after receiving a new command.
BFR Bus Free Phase - Use this bit to cause an immediate Bus Free phase. The adapter will send no message bytes before going to Bus Free phase. This bit can be used to cause an unexpected disconnect.
0 ⇒ This option will not be used.
1 ⇒ The adapter will immediately go to Bus Free phase.
CMD Command Phase - Use this bit to cause the adapter to go to Command phase and receive a new command from the initiator. Use the SMB with this bit if a specified Message byte should be sent before going to Command phase. This bit is only used to recover from unexpected events.
0 ⇒ This option will not be used.
1 ⇒ The adapter will go to Command phase to receive a new command from the initiator.
NSC Normal SCSI command termination - Use this bit to cause the adapter to terminate a normal command. The adapter will send the Status Byte followed by the Message Byte and then go to Bus Free phase.
0 ⇒ This option will not be used.
1 ⇒ The adapter will terminate the command by going to Bus Free phase after sending the Status Byte followed by the Message Byte.
User’s Guide | 21020285 D |
