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Service Guide OKIPAGE4w
Chapter 2 Operation Description
Main Control Board
The main control board consists of a one-chip CPU, a program ROM, a DRAM, an EEPROM, a host
interface circuit, and a mechanism driving circuit. The mechanism driving circuit consists of an LED
head, a main motor, and an electromagnetic clutch.
(1) One-chip CPU
The one-chip CPU is a custom CPU (8-bit internal bus, 8-bit external bus, 10-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. EPROM is used as program ROM. When mask
ROM in the one-chip CPU explained in (1) above is valid, the EPROM is not mounted. (For details on
short wiring setting, see Section 7.2.)
(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 IEEE1284 specification.
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