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MAIN PCBS AND THEIR FUNCTIONS
2.8.2 SCU (SCANNER CONTROL UNIT)
SCU
O d d
E v e n
E P R O M
4 Mbit (x16)
This is the main board. The functions of each component are as follows.
CPU: HD6413002F
• Scanner sequence control
• Clock/timer control
• DMA control
IPU (Image Processing Unit):
• Shading correction
• Image processing (Mirror image, reproduction ratios, MTF correction, binary
picture processing, edge extraction, and so on)
Memory Controller:
• Stores the image data from the IPU in the memory (DRAM 32 Mbytes x 2).
• Address control when recalling the data from the memory.
SCSI controller: SCSI interface controller.
SRAM: Work area (32 kbytes)
EPROM: Contains the program.
Enhanced I/O (EIO):
• Extension for the I/O port.
• DIP switches (mode selection), rotary switches (SCSI ID setting), and a push
switch (reset button) are connected.
2
E
PROM: Holds the book, ADF, and lamp counter values.
S E L
IPU
O S C
C P U B u s
2
S R A M
E
P R O M
2 5 6 kbit (x8)
2 kbit
Reset IC
Image data
E R C U
Memory
Controller
O S C
D R A M
16 Mbit (x16)
C P U
O S C
Signal line
2-28
16 February 2000
V R S
S C S I
Controller
SCSI
Terminator
EIO
D I P S W
SCSI ID
Rotary
S W
G413D512.WMF
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