Eeprom Control Circuit; Cs Motor Circuit - Epson LQ-300 Service Manual

Operating Principles

2.3.11 EEPROM Control Circuit

Figure 2-23 shows the EEPROM control circuit block diagram. The EEPROM (IC6) contains such
information as the top-of-form position. The EEPROM is non-volatile memory, so information is
not lost if the printer is powered off. Since the EEPROM is a serial I/O-type device, the CPU
converts 8-bit data into serial data.
CPU (lCl)
Figure 2-23. EEPROM Control Circuit Diagram

2.3.12 CS Motor Circuit

Figure 2-24 shows a block diagram of the CS motor circuit in the optional color upgrade kit. The
CS motor is a permanent magnet (PM) stepping motor, driven with 2-2 phase exatation in
proportion to the desired rotational speed. This motor can be rotated in either direction and
stopped at any position. Four phase signals are directly output from the system IC and pass
through a tcansistorarray. The drive voltage is constant (i.e., +35 VDC from the VP line).
Source Voltage
Current Consumption
GATE ARRAY (IC2)
2-18
05
06
3
07
4
35 VDc * 10
245 mA ( peak)
I
1
49
4a
47
04 *
Printer
Motor Circuit
Figure 2-24. CS
+5
A
Cs
Vcc L}
DO
GND
'
Q1
CS A
Color Upgrade Kit
v