FUJITSU M3093DG - Manual (Page 84)

4.4.6 TEST UNIT READY command
The following table shows the normal sequence of the TEST UNIT READY
command when used with this scanner.
Step Bus phase Initiator operation ¨ Æ Target operation
1 BUS FREE Verifies bus free
2 ARBITRATION Obtains bus>usage
right
3 SELECTION Selects target Æ
Drives BSY signal
4 MESSAGE OUT Selects logical unit Æ
5 COMMAND Specifies TEST
UNIT READY
(CDB) Æ
6 STATUS ¨ Reports GOOD status
7 MESSAGE IN ¨ Reports message (Command
Complete)
Releases BSY signal
8 BUS FREE
(1) TEST UNIT READY command: COMMAND phase (initiator Æ target)
The TEST UNIT READY command checks whether a logical unit is ready. This
command does not request self>test. The acknowledgment of this command reported
using the status and sense data.
The CDB of this command is shown in the following illustration.
1
Byte 0
2
3
4
5
Operation code X©00π
(Reserved)
(Reserved)
Control byte
7 6 5 4 3 2 1 0
Logical unit number
4 $ 52