Filter
Top Products
User’s Guide 21020285 D
Chapter 6 Target Mode Pass-through Commands
Target Mode Response Command Page 6 - 15
Target Mode
Response
Command
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.
Note
This command must be
issued from a Command
List in order to
accommodate the
possibility of two Status
Blocks being returned.
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 operations—send
data, send Save Data Pointer message, send Disconnect message, and
disconnect; second Target Mode Response command operations—reconnect,
send more data, send status, send Command Complete message, and
disconnect.
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.
Command
Format
The Parameter Block format for the Target Mode Response command looks
like this:
Description of
Fields
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.
Address
Offset
Byte Memory Address
Offset + 0 Offset + 1 Offset + 2 Offset + 3
00H Command Identifier
04H LUN Flags-1 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
Table 49: Target Mode Response Parameter Block