User`s manual

SIOP Firmware Structures
B-10 Single Board Computers SCSI Software UserÕs Manual
B
Device Address or SIOP Interrupt Level
initiator mode
The user initializes the device address field with the SCSI address of the device
to be accessed. For example, a command for SCSI address 4, LUN 2 would
need a 0x00000004 placed in this field.
config mode
TAG_Q bit set-
The user initializes the device address field with the SCSI address of the target
device that supports tagged command queuing. For example, SCSI address 6,
LUN 1 would need a 0x00000006 placed in this field.
SCSIADD bit set-
The user initializes this field with the SCSI address that the
MVME167/MVME187 SCSI port (SIOP) is to occupy. For example, if the user
wants the SIOP to occupy address 4 then 0x00000004 would be placed in this
field. This field is not checked for erroneous values. Instead, it is interpreted
as a modulo 8 value; therefore, a hex value of 0xf9 is read as 0x01.
SCSIINT bit set-
The user initializes this field to the level (1 through 7) at which the SIOP is to
interrupt the MPU. For polled mode (Firmware does not relinquish processor
until command is complete) this field is cleared (0x00). This field is not
checked for erroneous values. Instead, it is interpreted as a modulo 8 value;
therefore, a hex value of 0x146578 is read as 0x00.
LUN
initiator mode
The user initializes the LUN field with the Logical Unit Number (LUN) of the
target device to be accessed. For example, a command for SCSI address 4,
LUN 2 would need a 0x00000002 placed in this field so the Firmware can
generate the correct identify message needed for selection.
config mode
TAG_Q bit set-
The user initializes the LUN field with the logical unit number of the target
device that supports tagged command queuing. For example, SCSI address 0,
LUN 1 would need a 0x00000001 placed in this field.