Epson EPL-5500 Service Manual page 69

Operating Principles
Table 2-1 lists the functions of the main elements of the video controller section in C169 MAIN-B
Board.
Table 2-1. Functions of C169 MAIN-B Board Main Elements
Element
MB86933H RISC IC1
CPU
E05A91 ASIC IC2
E05A92 ASIC IC3
E05A93 ASIC IC4
Two 8M ROMs or IC21,22 or
four 4M ROMs IC13,14,15,16
8M ROM IC12
EEPROM IC11
DRAM IC17,18
2-18
Location
The CPU, which operates at 22.5 MHz, manages the video
controller operation.
This ASIC contains the following functions:
•Address decoding
•DRAM management (refresh control,
RAS/CAS control)
This ASIC contains the following functions:
•Video signal processing
•Toner save function
•BiRITech
•EMGTech
This ASIC contains the following functions:
•Video interface
•Bi-parallel interface
•LocalTalk module control
•Type-B EX interface box control
These ROMs are code and font ROMs.
This ROM is a local language (font) ROM option (except in
the U.S. model).
This EEPROM stores the following:
•Model type
•Printed page counter value
•Jam counter value
•Printer setting
These DRAMs are used as the working area of the CPU:
input buffer, image buffer, etc.
EPL-5500 Service Manual
Function
Rev. B