Fujitsu 600C manual Scan command, SCAN Command phase initiator → target, Step, Bus phase

Models: 600C

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4.4.10Scan command

This scanner calculates the numbers of X-direction pixels and Y-direction pixels of the image data to be transferred to the initiator. The scanner performs this calculation by referencing the resolution and area up with the SET WINDOW command. This data need not be issued if the number of pixels are known 1 the initiator.

The transfer format for this data is shown in the following illustration.

Byte 0

3

4

7

8

F

(MSB)

Number of X-direction pixels

(LSB)

(MSB)

Number of Y-direction pixels

(LSB)

(Reserved)

4.4.10Scan command

The following table shows the normal sequence of the SCAN command when used with this scanner.

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 SCAN (CDB)

 

6

DATA OUT

 

Transfer data

7

STATUS

 

Reports GOOD status

8

MESSAGE IN

 

Reports message (Command Complete)

 

 

 

 

Releases BSY signal

9

BUS FREE

 

 

 

4.4.10.1SCAN Command phase (initiator target)

The Scan Command requests the target begin a scan operation. It is required for scanning color image, but not required for scan B/W image.

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Image 77
Fujitsu 600C Scan command, SCAN Command phase initiator → target, Step, Bus phase, Initiator operation, Target operation