Request Sense Command; Request Sense Command: Command Phase (Initiator → → Target) - Fujitsu Scan Partner 300C Instruction Manual

4.4.4 REQUEST SENSE command

The following table shows the normal sequence of the REQUEST SENSE command when used with this scanner.
Step
1
2
3
4
5
6
7
8
9
4.4.4.1 REQUEST SENSE command: COMMAND phase (initiator
The REQUEST SENSE command requests the sense data that shows the status of a logical unit. On receiving this command,
the target sets the unit's status in the sense data and returns it to the initiator.
The CDB of this command is shown in the following illustration.
Byte 0
1
2
3
4
5
Table 4-11 REQUEST SENSE command
Bus phase Initiator operation
BUS FREE Verifies bus free
ARBITRATION Obtains bus-usage right
SELECTION Selects target
MESSAGE OUT Selects logical unit
COMMAND Specifies REQUEST
SENSE (CDB)
DATA IN
STATUS
MESSAGE IN
BUS FREE
7
6 5
Logical unit number
← ← → →
Target operation
→ →
Drives BSY signal
→ →
→ →
← ←
Reports sense data
← ←
Reports GOOD status
← ←
Reports message
(Command Complete)
Releases BSY signal
4 3
Operation code X'03'
(Reserved)
(Reserved)
Allocation length
Control byte
4-26
→ →
target)
2 1 0