Scan Command; Scan Command Phase (Initiator → Target) - Fujitsu Scan Partner 300C Instruction Manual

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
(MSB)

3
4
(MSB)

7
8

F

4.4.10 Scan command

The following table shows the normal sequence of the SCAN command when used with this scanner.
Step Bus phase
1 BUS FREE
2 ARBITRATION
3 SELECTION
4 MESSAGE OUT
5 COMMAND
6 DATA OUT
7 STATUS
8 MESSAGE IN
9 BUS FREE
SCAN Command phase (initiator → target)
4.4.10.1
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.
Number of X-direction pixels
Number of Y-direction pixels
(Reserved)
Initiator operation
Verifies bus-free
Obtains bus-usage right
Selects target
Selects logical unit
Specifies SCAN (CDB)
4-49
← ← → →
Target operation
→
Drives BSY signal
→
→
→
Transfer data
←
Reports GOOD status
←
Reports message (Command Complete)
Releases BSY signal
(LSB)
(LSB)