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2 release unit command, Release unit command – FUJITSU M3097G User Manual

Page 49

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4.4.2

RELEASE UNIT command

The following table shows the normal sequence of the RESERVE UNIT 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
RELEASE UNIT
(CDB)

Æ

6

STATUS

¨

Reports GOOD status

7

MESSAGE IN

¨

Reports message (Command
Complete)

Releases BSY signal

8

BUS FREE

(1)

RELEASE UNIT command: COMMAND phase (initiator Æ target)

The RELEASE UNIT command releases a reserved status. If this command comes
from an initiator that has not declared reservation, the target ignores the command
and responds with the GOOD status (the reserved status is not released).

The CDB of this command is shown in the following illustration.

Byte 0

Operation code X©17π

2

3

4

5

TP

TPID

(Reserved)

(Reserved)

Control byte

1

7

6

5

4

3

2

1

0

Logical unit number

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