Epson DLQ-3000 Service Manual page 49

The functions of the main ICS are as follows.
Main CPU I.LPD70433/V55PI (IC1O)
This is the main CPU, which receives data from the host computer directly (parallel) or via the gate
array E05A88 (serial) and store the data in the D-RAM input buffer.
Then, when a print start interrupt occurs (CR code, or buffer full), it transfers the input buffer data
to the CG (character generator) and converts the data into image data.
The four printing modes of the printer correspond to the four different drive conditions, and in
each the energizing pulse width is modified (i.e. lengthens or shortens the time) based on the
information from the sensors (voltage, PG, and head temperature).
The main CPU has parallel I/F and the input buffer control hardware.
The main CPU directly controls the reception from each mechanism sensor, platen feed motor,
carriage motor and control panel.
The built-in 8-channel 8-bit A/D converter is used for the V source voltage check and head
temperature detection. For abnormal voltage drops on the +V, an interrupt port is used to execute
a physical interrupt (error detection).
Gate Array E05A88 (IC1l)
This is a l-chip gate array which handles the following functions.
- Clock Control Unit (CCU) :
- Address Latch (ALU):
- AB20 Control Unit (AXU)
- Memory Management Unit (MMU):
- DRAM Control Unit (DCU)
- I/F Control Unit (IFU):
I/F Control Unit (TIB):
Type-B
- Port Control Unit (PCU):
- RF Motor Control Unit (MCU)
- Bit Manipulation Unit (BMU):
- Head Control Uni (HCU)
- Head Control Unit 2 (HCU2)
- Read Data Unit (RDU):
Gate Array E05A89
This is a l-chip gate array used for controlling the control panel interface.
Inter 28FO10 (lMbit Flash-EEPROM, IC13)
The memory is the CPU program ROM which contains the firmware that controls the mechanisms,
Character Code Table, Panel message and all of the control programs for the main printer. The
program can be reloaded from an external PC.
A mask ROM which contains printing pattern, Character code table, multi-font character
generation, panel message and Boot-strap program is provided as standard equipment.
HM514256A/AL (1-Kbyte D-RAM, IC19,20)
This RAM is used as the CPU working area. Internally, it is mapped as the print data expansion
area for the data input buffer, line buffer, image buffer, etc.
93LC46 (EEPROM, IC16)
This EEPROM stores and protects the hardware settings for the bi-directional adjustment value,
and data for SELEC1l'PE settings, TOF positions, TEAR OFF amount, etc. When power is off,
these data are protected by interrupt program.
If the combination of main board and mechanisms changes, the settings must be rewritten by the
program. (Refer to Section 4.5)
Outputs clock pulse
Latches and outputs the lower address.
PROG select, CGROM select, QPIT select, MMIO1
select, etc.
Output of BUSY, ERR, PE, SLCT and SL245 signals
Option I/F select
CR current, PF current, LOD / PEW sensor read enable
and VPPENB signal control
Double-Height rendition manipulation, etc.
Outputs internal MMIO data
Operating Principles
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