Scanner Interface

A.4.13 MODE SENSE (6)

The normal MODE SENSE (6) sequence for the scanner is as follows:

Step

Bus phase

Initiator operation

← →

Target operation

 

 

 

 

 

1

Bus Free

Checks Bus Free

 

 

 

 

 

 

 

2

(Arbitration)

Acquires the bus use

 

 

 

 

right

 

 

 

 

 

 

 

3

Selection

Selects the target

 

 

 

 

 

 

 

 

 

 

Drives the BSY signal

 

 

 

 

 

4

(Message Out)

Selects the logical

 

 

 

device

 

 

 

 

 

 

 

5

Command

Specifies MODE

 

 

 

SENSE (6) (CDB)

 

 

 

 

 

 

 

6

Data In

Specifies MODE

Reports mode data

 

 

SENSE parameter

 

 

 

 

data

 

 

 

 

 

 

 

7

Status

 

Reports the GOOD status

 

 

 

 

 

8

Message In

 

Reports message

 

 

 

 

(Command complete)

 

 

 

 

 

 

 

 

 

Releases the BSY signal

 

 

 

 

 

9

Bus Free

 

 

 

 

 

 

 

 

(1)MODE SENSE (6) command: Command phase (Initiator to Target)

The MODE SENSE (6) command is used for the target to report mode parameters to the initiator. The command descriptor block (CDB) is as follows:

7

6

 

5

4

3

 

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

Byte 0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Operation code X’1A’

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

Logical unit number

 

Reserved

DBD

 

 

Reserved

 

2

 

 

 

 

 

 

 

 

 

 

 

 

PC

 

 

 

Page code

 

 

 

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reserved

 

 

 

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Allocation length

 

 

 

5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Control byte

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appendix A-100