C304Main Board Circuit Operation Principles - Epson Stylus PHOTO 2000P Service Manual

EPSON Stylus PHOTO 2000P

2.2.2 C304MAIN Board Circuit Operation Principles

The C304MAIN board includes the following:
Logic circuit (CPU, ASIC, DRAM, EEPROM, and so on)
Various motor control/driver circuits (CR motor, PF motor, and
ASF/Pump motor)
Head control/driver circuits
Interface circuit (parallel I/F, USB I/F)
Sensor circuit
Timer circuit
Reset circuit
The C304MAIN board is mainly different from other main boards in the
following two points.
1) Use of 3.3V drive logic chips
IC9, the 3.3 V regulator IC on the C304MAIN, produces 3.3 V by
pressuring down the 5.5 VDC generated on the C298PSB/PSE board to
drive several chips. These chips are used to reduce power used to
drive the logic circuit. See the table below that separately shows the
chips driven by the +5V and +3V.
Table 2-18. 3.3V Drive Chips & 5.5V Drive Chips
Table 2-19.
+5V
Sensors
I/F Circuit
PNL Board
2) Use of slave CPU
Since the CR motor and PF motor of this printer are DC motors, a
slave CPU is attached on the main board in addition to the CPU and
ASIC. This slave CPU exclusively controls the DC motors to remove
the task from the CPU and ASIC. So the CPU and ASIC can process
data faster than before.
OPERATING PRINCIPLES
3.3V
CPU
ASIC
P-ROM
D-RAM
Electrical Circuit Operating Principles
NOTE: The control board has C304Main board and C298MAIN board.
C209MAIN Board is named IC25, which is composed of IC20 and IC8.
See Figure 2-13 for the C304MAIN board block diagram.
CR Encoder senser
CN8 HD FFC
Head
Batt1
D-RAM 16M
P-ROM 16M
(IC3)
(IC2)
Address
Data
C90A11CA
E05B70CD
CPU (IC20)
ASIC (IC8)
Address
Data
IC7
E0BA13KA
CN3
CN7
USB
IC21
PDIUSBF11A
When it works as C298MAIN-B,
E01A13 (IC25)
Figure 2-13. Block Diagram for the C304MAIN Board
Revision A
CR Motor
CN9 HD FFC
CR1
PF Motor
Q3&Q4
ASF/Pump Motor
Timer &
Reset IC
Common
(IC5)
CN14
Driver
(IC10 or
IC11) CN13 CN7
EEPROM
(IC6)
Motor Motor
Motor
Driver Driver Driver
(IC19) (IC12)
(IC18)
C90A26CA
Slave CPU (IC15)
IC4
CN1 Parallel
74VHC1612B4
CN11
C304PNL Board
CN 6
CN5
ASF Sensor
PE Sensor
PF Encoder Sensor
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