EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 60
The following tables list the major components on the C265 main board
and their functions.
Table 2-14. Major Components on the C265 Main Board (1/2)
Table 2-15. Major Components on the C265 Main Board (2/2)
Component Functions
CPU:
• A Hitachi H8-series CPU.
• Performs high-speed data processing running at 24.0
Mhz with an external transmitter.
• Bus width is 16-bit.
ASIC 1:
(E05B60: IC3)
• Controls all interfaces but USB.
• Monitors the signal from each sensor.
ASIC 2:
(E05B59: IC2)
• Controls printheads, motors, ASF solenoid, cooling fan,
USB I/F, and EEPROM.
PROM/MROM:
• For PROM, either one-time PROM or Mask ROM is
used. Specifications vary depending on the
destinations, as shown below:
<Standard version>
• PROM size: 16 M bit
• Contents: Unattached
• Bus width: 16 bit
<NLSP version>
• PROM size: 16 M bit
• Contents: 16 M bit
• Bus width: 16 bit
D-RAM:
• Manages the various buffers and work area.
• Bus width is 16 M bit.
Timer IC:
(RTC9810: IC8)
• Counts total power off time of the printer, which offers
the basis for determining the cleaning type to be
performed at the next power on. Power is supplied by
an external button-cell battery (a lithium battery). This
IC also serves to produce reset signals connecting to
each major IC, such as CPU, ASIC1, ASIC 2, and motor
drive ICs. The head driver ICs (CXA2128 x 2: IC15 and
IC16) individually produce a reset signal when detecting
abnormal voltage so the printhead can stop in the
proper sequence.
Component Functions
Motor driver IC
(LB1847: IC11, 12)
(A3957: IC13, 14)
• The LB1847 (IC11 and IC12) is used to drive PF motor
and CR motor and enables 4W1-2 phase excitation
mode for the first in EPSON line. This control system,
called micro stepping, materializes the control of the
carriage vibration during printing and improvement of
accuracy in paper feeding on the hardware basis.
• The A3957 (IC13 and IC14) used to drive Pump, ASF
motor also supports the 4W1-2 phase excitation mode on
the hardware basis, but differs from the former IC in the
point that the IC13 and IC14 individually excite the phase
A and B.
Head driver IC
(CXA2128 x 2: IC15,
16)
• The head driver ICs, directory attached to the board,
consist of two separate circuits; charging circuit and
discharging circuit, to produce trapezoidal waveform.
This IC creates the trapezoidal waveform by combining
the signals input from the input port E05B59 (IC2) of the
IC. This is performed to change the characteristics and
voltage levels of charging and discharging, and the
trapezoidal waveforms specific to normal dot print and
micro dot print are produced as the result.
