Epson C11C605001 - DFX 9000 B/W Dot-matrix Printer Service Manual page 76

OperatingPrinciples
Table 2-2 lists the functions of the C135 MAIN board main elements.
Table 2-2. Functions of
Location
MB86930 RISC
ICI
CPU
IC1615 or
four ROMs
4M
Two 8M ROMs
BM ROM
27
2-24
MAIN Board Main Elements
The CPU, which operates at 19.2 MHz, manages the video
controller operation.
This ASIC contains the fdbwing functions:
Address decoding
. DRAM management (refresh control,
This ASIC contains the fdbwing functions:
video signal processing
.
EMGTech
This ASIC contains the folbwing functions:
Video interface
. LocalTalk module control
. Type-B interface card control
,
These ROMs are font ROM.
This ROM is local language ROM (fonts) option.
This EEPROM stores the fdbwing:
. Model type
. Printed page counter value
. Toner life counter value
. Jam counter value
These DRAMs are used as the working area of the CPU:
input buffer, image buffer, etc.
This IC changes the RS-232C signal level.
This IC changes the RS-422 signal level.
Function
Rev. A