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21020285 D User’s Guide
Chapter 6 Target Mode Pass-through Commands
Page 6 - 16 Target Mode Response Command
Flags-1
The Flags-1 byte contains specific controls for the operation of the Target Mode
Response command. The format is as follows:
DIR Direction of Data Transfer - If a data transfer is required to complete
a command, use this bit to inform the adapter of the direction the data is to be
transferred. This bit is only significant if the DAT bit is set to one.
Note
The RF3880 is acting as
a target when executing
a Target Mode Response
command.
0 ⇒ Data transfer is from the initiator.
1 ⇒ Data transfer is to the initiator.
DAT Data Transfer - Use this bit to inform the adapter that the command it
is to perform involves a data transfer. This bit is used by the adapter in
conjunction with the DIR bit.
0 ⇒ Command requires no Data phase.
1 ⇒ A Data phase is required for this command.
TMO Target Mode Operation - This bit distinguishes Target Mode
Response commands from Initiator Mode Pass-through commands
0 ⇒ Initiator Mode Pass-through command
1 ⇒ Target Mode Response command.
ICC Inhibit Command Complete Interrupt - This bit is used to inhibit the
interrupt that would normally notify you that the command has completed.
0 ⇒ Interrupt using the Interrupt level indicated in the Interrupt field of the
Start Command List command, when the command has completed.
1 ⇒ Do not interrupt to indicate command completion.
LUN
When the initiator selected the RF3880, it specified a LUN in its Identify
message. For reselection, this byte contains that same logical unit number
(LUN).
VME Memory Address
When the SCSI operation requested by the initiator that selected the RF3880
involves a data transfer, this field contains the beginning Host memory address
for the transfer. This field is ignored for SCSI transactions that require no
transfer of data.
Transfer Count
Note
A value of zero indicates
a transfer of 4 billion
bytes, and should not be
used.
The value placed in this field indicates the number of bytes to be transferred to
or from Host memory. For some SCSI commands this is an indeterminate
number. In that case, use the number of bytes allocated in Host memory for this
Data area.
BITS
76543210
0 0 ICC TMO 0 DAT DIR 0
Table 50: Bit-meanings of Flags-1 Field