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4-19
(d) A bit and field described as "Reserved" are 0.
If this scanner receives a value other than 0, it returns an error as follows:
Status key: B'00001 '(CHECK CONDITON)
Sense key: X~5'(ILLEGAL REQUES~I)
The commands supported by this scanner are listed below.
Table 4-7 Commands
Command
Operation
code (hex) Description
RESERVE UNIT 16 Declares the exclusive use of a logical unit
RELEASE UNIT 17 Cancels the declaration of the exclusive use of a logical unit
INQUIRY 12 Examines the information regarding the target and logical unit
REQUEST SENSE 03 Requests a target for sense data
SEND DIAGNOSTIC ID Requests a target for self-check
TEST UNIT READY 00 Checks whether or not a logical unit is ready
SET WINDOW 24 Sets a window
OBJECT POSITION 31 Controls the automatic document feeder
READ 28 Requests transfer of image data
SCAN 1B Requests the target to begin a scan operation
4.4.1 RESERVE UNIT command
The following table shows the normal sequence of the RESERVE UNIT command when used with this scanner.
Table 4-8 RESERVE UNIT command
Step Bus phase Initiator operation
←←→→
Target operation
1 BUS FREE Verifies bus free
2 ARBITRATION Obtains bus-usage right
3 SELECTION Selects target
→
Drives BSY signal
4 MESSAGE OUT Selects logical unit
→
5 COMMAND Specifies RESERVE UNIT (CDB)
→
6 STATUS Reports GOOD status
7 MESSAGE IN
←
Reports message
(Command complete)
Releases ESY signal
8 BUS FREE