Canon Fax-L260i, Service Manual

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FAX-L260i Chapter 2: Technical Reference
5.2 Circuit Board Components
a) System control section
The system controller is made up of the following components, and controls the entire fax system.
a-1) MPU (Micro Processor Unit) (IC1)
The main functions of the NEC µPD70433GJ-16-3EB MPU are as follows:
•16 bit CPU
•24 bit address bus
•8 bit data bus
•DMA control
•A/D converter
•Software CODEC
•Interrupt control unit
a-2) System controller (IC10)
The system controller is a gate array for controlling MPU peripheral devices. The main functions of the
system controller are as follows:
•Printer resolution conversion (Smoothing)
•LBP video interface
The LBP video interface transfers print signals to or from the printer controller and sends them to the
MPU. The interface transmits an image signal (nVDO) and a vertical sync signal (nTOP) to the printer
section, receives a horizontal sync signal (nBD) and printer section status from the printer section and
transfers them to the MPU.
•OPCNT serial interface
•DRAM/SRAM controller
Controls DRAM/SRAM read/write and refreshing.
•Document feed motor control
•Reduction in vertical scanning
•Recording decoder
a-3) RTC (Real Time Clock) IC (IC2)
A SII S3510ANFJ-TB is used as the RTC. The RTC IC is backed up by lithium battery, and counts the
date and time.
a-4) Main ROM (IC4)
This 8 Mbit ROM contains the control programs (e.g. operation panel, scanner and communications
section etc.) for this fax.
a-5) SRAM (IC5)
This 256 kbit SRAM is backed up by lithium battery. SRAM holds data registered for system control and
communications management information.
a-6) DRAM (IC7, IC8)
This 16 Mbit is used as memory for storing image data, and as an MPU work area.