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6 test unit ready command, Test unit ready command – FUJITSU M3097G User Manual

Page 61

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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

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