Main Control Board; Pcb Layout - Oki OKIPAGE 6w Maintenance Manual

2.1

Main Control Board

The main control board consists of a one-chip MCPU, which contains the program ROM, a DRAM,
an EEPROM, a host interface circuit, and a mechanism driving circuit. The mechanism driving
circuit consists of a LED head, a main motor, and an electromagnetic clutch.
Built-in Device
DRAM controller
DMA controller
Parallel interface controller
Video output port
LED STB output port
Timer
I/O port
A/D converter
(1) OKIPAGE 6w
The one-chip CPU is a custom CPU (8-bit internal bus, 8-bit external bus, 16-MHz clock)
incorporating mask ROM and CPU peripheral devices. This CPU has the functions listed in
the table below.
(2) • Program ROM
Program ROM contains a program for the equipment. Program ROM data is contained with
the MCPU. For details of PCB Layout see Section 7.2.2.
(3) DRAM
DRAM is used as resident memory.
(4) EEPROM
EEPROM holds the following data:
• Menu data
• Counter value
• Adjustment value
(5) Parallel interface
The parallel interface receives parallel data from the host; it conforms to the Centronics
specification. IEEE-1284 B: – directional parallel is supported.
Controls DRAM.
Transfers image data from Parallel I/F to DRAM, from DRAM to a video output port and
between CPU and DRAM.
Controls the parallel interface.
Controls LED head.
Generates various control timings for monitoring paper feeding and a paper size.
Inputs and outputs the sensor signals and motor signals, etc.
Also performs I/O for EEPROM.
Inputs the feedback signals from a high-voltage generation circuit and thermistor signal.
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Function