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