9-3)Reset Circuit; 9-4) Door S/W Circuit - Samsung RB1855SW Service Manual

Circuit Descriptions

9-3)Reset Circuit

Port
Vcc
Reset

9-4) Door S/W Circuit

Door Conditions
DOOR
CLOSE
F
OPEN
CLOSE
R
OPEN
1) If door is open, door S/W contact is closed. Then MICOM receives "low" signal and detects
door open then, Relay control circuit receives "HIGH" signal and turn Lamp on.
2) If door is closed, door S/W contact is open. Then MICOM receives "high" signal and detects
door close then, Relay control circuit receives "LOW" signal and turn Lamp off.
Voltage
5V
5V
Door S/W Contact
OPEN
CLOSE
OPEN
CLOSE
When power is supplied to MICOM, reset circuit
initializes RAM and other parts on MICOM to
initialize all programs. Reset voltage maintains "low"
for hundreds of µsec comparing to MICOM Vcc
voltage when power is input. It also maintains
"high"(5V) during normal operation. But, when Vcc
drops to 3.4V-3.7V, reset port becomes "low".
MICOM
PIN NO
# 39
# 40
29
Micom Input Voltage
"HIGH"
"LOW"
"HIGH"
"LOW"