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DETAILED SECTION DESCRIPTIONS
PCBs AND THEIR FUNCTIONS
2.5.3. SCU (Scanner Control Unit)
MBU
The image data from the SBU goes to the SCU through the MBU. Image
processing on this data is done in the SCU. Then the data goes to the host
computer through the SCSI interface (SCSI I/F). The functions of each
component are as follows.
SIP3 (Scanner Imageing Peripheral):
•
Generates the basic drive clock for the CCD.
•
Shading correction
•
Image processing (Mirror image, Reproduction ratios, MTF correction,
Binary picture processing, Edge extraction, and so on)
•
The connected FIFO (5 kbytes x 4) is used for line memory.
•
The connected SRAM (8 kbytes x 3) is used as an image data buffer.
SBC (Scan Buffer Controller):
•
Stores the image data from the SIP3 in the memory (DRAM 512 kbytes
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:
•
Extension for the I/O port.
•
DIP switches (mode selection), rotary switches (SCSI ID setting), and a
push switch (reset button) are connected.
EEPROM: Holds the book, ADF, and lamp counter values.
IEU
SCU
SEL
SRAM
SIP3
FIFO
CPU BUS
EEPROM
Enhanced
CPU
I/O
Dip SW
Rotary SW
Push SW
2-22
DCU or VIU
SCSI
controller
SEL
SEL
EPROM
SRAM
SBC
DRAM
Image data
October 9th, 1995
SCSI
I/F
G404D506.wmf
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