Epson Stylus Color 1160 - Reset Circuit

EPSON Stylus COLOR 860/1160 Revision C
Operating Principles Electrical Circuit Operating Principles 46
2.2.2.2 Reset Circuit
Reset circuits are attached on the C298MAIN 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 and ASIC. This function is necessary to prevent the printer from operating
abnormally. IC5 RTC-9820SA, a reset circuit IC, is attached directly on the
main board. This IC monitors both the +5V and +45 lines but can reset them
independently. See Figure 2-18 for the block diagram for the reset circuits.
o +5V line reset circuit
The VDD port of the IC5 reset IC monitors the +5V line. When the IC
detects an abnormal voltage level (4.3 V or lower), it outputs a reset signal
from the RST port to CPU and ASIC.
o +42V line reset circuit
The VIN port of the IC5 reset IC monitors the +45V line. When the IC
detects an abnormal voltage level (35.5V or lower), it outputs a reset signal
from the VDT port to CPU and ASIC.
NOTE: IC5, also serving as RIC (Real Time Clock), manages timer control when the
printer power is turned off. Power for this operation is supplied from the BAT1.
Figure 2-18. Reset Circuit Block Diagram
NMI
VDT
FRST
RST
C E
SCLK
DATA
VIN
VDD
VBK
GND
+42V
+5V
MRES
RESET
C21
0.1U
C19
0.1U
C18
0.1U
TCE
TCLK
TDATA
D2
SB007-03CPTB
IC 8
E05B70C D
BAT1
CR2032
+3.3V
R26
3.3K
R27
3.3K