Controller Circuit - Epson DLQ-3000 Service Manual

2.3 Controller Circuit

This section describes the controller circuit of this printer. This printer uses a 112-pin/QFP-
type/16-bit microprocessor H8/3003 (IC16) for the CPU and drives it with the clock
frequency of 14.7 MHz. The control program is stored in the 1-Mbit Flash-ROM (IC15) or
PROM (IC18).The CPU receives the external reset signal and control the printer based on
the control program. When the Flash-ROM is in use, the control program can be transferred
by way of the parallel interface. DRAM is used as a work area and buffers. A non-volatile
memory EEPROM (IC23) stores information such as default values, customer data, total
printing amount value and PG adjustment value. The gate array E05B46 (IC25) controls the
following:
Clock
Type-B I/F
It is also used for the PG measurement. The gate array E05A89 functions as the panel
interface controlled by the CPU. It is directly attached to the control panel circuit board to
simplify the circuits. See Table 2-10 which lists the main ICs and their functions.
Rev. A
Addresses Memory
Ports Motors
Operating Principles
DRAM Parallel I/F
Bitmap Printheads
2-15