Epson Stylus PHOTO 890 Service Manual page 49

EPSON Stylus Photo 890/1280/1290
Table 2-16 shows the major ICs on the C393MAIN Board and their functions.
OPERATING PRINCIPLES
Table 2-16. Major Element on C393MAIN
IC Location
CPU (HD6412670)
IC18
(C393MAIN/
C393MAIN-C)
ASIC (E05B87**)
(C393MAIN/
C393MAIN-C)
IC19
ASIC
IC19
(E01A20CA**)
PROM IC2
DRAM IC5
RTC IC
IC4
RTC9822**
Electrical Circuit Operating Principles
Functions
A 144-pin QFP package. Operates at 24.0MHz. Power supply voltage is
3.3V.
• Sets the current value for the ASF/Pump motor.
• Measures the printhead temperature.
• Several interrupting functions
• Outputs the system clock signal.
A 240-pin QFP package. Operates at 48.0MHz/24.0MHz/28.0MHz. Power
supply voltage is 3.3V.
• Controls interfaces.
• Controls specified motors.
• Controls the printhead drive waveform circuit.
• Transfers serial data to the printhead.
• Controls the ASF/Pump motor
• Receives panel control signals and sensor signals
• EEPROM
• Controls detection of the signals output from the encoder.
• CPU and ASIC are built in in the IC.
8/16Mbit
• Stores the firmware or firmware +CG
A 16Mbit DRAM. Power supply voltage is 3.3V.
• Serves as specified buffers and work area
• Resets the +5V/+24 VDC line circuits.
• Serves as the timer powered by a lithium battery.
Revision C
49