Cr / Pf Motor (Pf/ Pump/ Asf Motor) Driver Circuit; Reset Circuit - Epson Stylus Color C70 Service Manual

EPSON Stylus COLOR C70/C80

2.2.2.3 CR / PF Motor (PF/ PUMP/ ASF Motor) Driver Circuit

The motor driver IC (IC8) on the MAIN board drives CR / PF motor. This product uses
DC motor and performs constant current PWM drive.
CPU (IC7) converts CR / PF motor REF control signal to A3974 micro step drive form
and outputs to motor driver IC (IC8)A3974 from port 52, 63. Based on this signal, IC8
determines the REF mode.
The current value on each phase is determined by CPU (IC7) and outputs from port 138
pin to driver IC (IC8). Motor driver IC generates motor driver waveform based on a
input signal and controls the motor. If the printer dose not receive any data from PC for
5 minutes, CPU set the motor drive current to 0 via port 138 pin and the motor drive is
turned off to save the power consumption.
The initial bit of the serial data that is output from pin 183 is set to a command that
specifies whether the CR motor or the PF motor is to be driven. This product does not
carry out any operations in which the CR motor and the PF motor are driven
simultaneously, and so control is possible using a single serial data line.
+5V
IC7 IC8
E01A27CA A3974
15
VDC
32
181
CLK4M OSC
52
14
C_P46 REF1
15
63
C_P47 REF2
184 31
SLEEP
RST_DCMCU
10
183
SDATA_DCMCU DATA
191 42
TIOCAO
ENABLE1
9
188
SCLK1_DCMCU CLOCK
189 8
SLD1_DCMCU
STROBE
197
26
TIOCA3
ENABLE2
1, 2
GND
22, 23, 24
GND
33, 34, 35
GND
44
GND
Figure 2-29. CR/PF Motor Driver Circuit Block Diagram
Operating Principles
+42V
+42V
CN14
43
VBB1
36
VCP
25
VBB2
6 1
OUT 1A
40 2
OUT 1B
3
SENSE1
37
CP1
38
CP2
30
VREG
CN13
18 1
OUT 2A
28 2
OUT 2B
21
SENSE2
11
GND
12
GND
13
GND
Electrical Circuit Operating Principles

2.2.2.4 Reset Circuit

Reset circuits consist of the rest IC (IC6 : Stylus COLOR C70, IC1 : Stylus COLOR
C80). Reset circuits are mounted on the MAIN board to monitor the two voltages: +5V
for the logic line and +42V for the drive line. When each circuit detects abnormality on
the corresponding line, it outputs a reset signal to reset CPU (IC7). This function is
necessary to prevent the printer from operating abnormally. This IC monitors both +5V
and +45 lines but can reset them independently. The reset circuits outputs reset signal
when +5V line becomes 4.2V or lower or +42V line becomes 33.2V or lower.
Unlike the previous products, Stylus C70 has no timer IC and both C70 and C80 have
no Lithium battery on the main board.
+5V
+42V
C80
C70
CR
Motor
PF
Motor
Figure 2-30. Reset Circuit Block Diagram
Main signal lines are explained below;
OUT1:
OUT2:
IN:
VCC:
C70
IC1
MN1347AFFE
1 8
NC1 MRES
2 7
VCC
IN
3 6
OUT1
NC2
4 5
OUT2
GND
C80
IC6
+3.3V
RTC9822SA
14 5
VDD CE
12 4
VI5
CLK
8
3
VDD2 DI
10 2
VEX DO
7
9
VSS EXO
1 13
NON
FRST
6
11
IRQ
RST
Interrupt signal
Reset line
+42V line monitoring line
+5V line monitoring line
Revision A
IC7
E01A27CA
C80
+3.3V
166
ECS
167
ECK
168
EDO
171
EDI
173
NMI
165
MRES
172
RESET
175
VLE
57