Chapter 6 Target Mode
Target Mode Response Command | Page 6 - 15 |
Target Mode
Response
Command
Note
This command must be issued from a Command List in order to accommodate the possibility of two Status Blocks being returned.
Command
Format
After the adapter has received a selection from an initiator and the Host has processed the data that it wrote into the Target Selection Data Structure, the Host must issue a Target Mode Response command to communicate information to be used by the RF3880 to respond to the initiator that selected it.
Target Mode Response commands are queued by the adapter for execution in the same manner in which the adapter queues commands when it is operating as an initiator. Multiple operations in a sequence can be performed on the SCSI bus. An example: first Target Mode Response command
An initiator can send an unexpected message at any time. The adapter will always accept the message, writing it into the Status Block in the Message Byte Received field.
The Parameter Block format for the Target Mode Response command looks like this:
Address |
| Byte Memory Address |
| |
Offset | Offset + 0 | Offset + 1 | Offset + 2 | Offset + 3 |
| ||||
00H |
| Command Identifier |
| |
|
|
|
|
|
04H | LUN | Addr Mod | Initiator ID | |
|
|
|
|
|
08H |
| VME Memory Address |
| |
|
|
|
| |
0CH |
| Transfer Count |
| |
|
|
|
| |
10H | Reserved | Rspse Cntrl Flgs | Reserved | |
|
|
|
|
|
14H | Queue Tag Msg | Queue Tag ID | Status/1st Msg | Message Byte |
|
|
|
|
|
18H |
| Reserved |
| |
Description of Fields
Table 49: Target Mode Response Parameter Block
Each of the fields used by the Target Mode Response command are explained in the following section:
Command Identifier
The Command Identifier is used to identify the Status Block associated with a Parameter Block. It must be a unique value.
Initiator ID
This field must contain the SCSI ID of the initiator that is to be reselected.
Address Modifier
This is the value that the adapter is to drive onto the VMEbus Address Modifier lines when selecting the memory address for the data transfer.
User’s Guide | 21020285 D |
