CHAPTER 2
2 - 12
COPYRIGHT
2000 CANON INC. CANOSCAN N650U/N656U/N1220U REV.0 JUNE 2000 PRINTED IN JAPAN (IMPRIME AU JAPON)
B. Document Scanning Sequence
Figure 2-9
Table 2-1
HPDET
STUP
SCFW
SCAN
SCRTN
STBY
STBY
(A4, 1200dpi, 100%, 24bit color)
8 sec.
SEQUENCE
Times required (s)
Drive motor (M1)
LED ON signal
Interface signal
(Data 1-8)
Scan command is received
Scanning unit position
Home position
Border between
black and white
: Reverse
Document scan area
After a power on sequence
is completed until the
scanner receives a scan
command from the host
computer.
To maintain the scanner
ready for scan.
After the scanner received a
scan command until the
home position is detected.
To detect the home position
and a border between black
and white.
If the border detection between
black and white is failed, the
scanning unit stops there and
proceeds to the next step.
After the home position is
detected until document
scan starts.
To make a gate array setting,
buffer RAM initialization, etc.
as a preparation for scan.
After the scanning unit
starts moving forward
until it reaches the
starting position of the
scan area specified by the
host computer.
To move the scanning unit
with a uniform speed to the
vertical scanning position
specified by the host
computer.
After the scanning unit
starts scanning until all
area specified by the host
computer are scanned.
To perform various image
processing according to the
command from the host
computer and transmit the
image data during scan.
After the scanning unit
starts moving backward
until it returns to the
home position.
To return the scanning unit
to the home position to
ready for the next scan.
The home position is detected
by the home position sensor.
Sequence
STBY
(Standby)
HPDET
(Home position
detection)
STUP
(Setup)
SCFW
(Scanning unit
forward)
SCAN
(Document
scan)
SCRTN
(Scanning unit
return)
Purpose
Remarks