Service manual

R-820JS
24
DESCRIPTION OF LSI
LSI
The I/O signal of the LSI are detailed in the following table.
Pin No. Signal I/O Description
1C1INTerminal not used.
2 VL1 IN Power source voltage input terminal.
Standard voltage for LCD.
3-6 AN7-AN4 IN Heating constant compensation terminal.
7 AN3 IN Temperature measurement input: OVEN THERMISTOR.
By inputting DC voltage corresponding to the temperature detected by the thermistor,
this input is converted into temperature by the A/D converter built into the LSI.
8 AN2 IN Input signal which communicates the door open/close information to LSI.
Door closed; "H" level signal.
Door opened; "L" level signal.
9-10 AN1-AN0 IN Terminal not used.
11 P57 OUT Timing signal output terminal for temperature measurement(OVEN THERMIS-
TOR).
"H" level (GND) : Thermistor OPEN timing.
"L" level (-5V) : Temperature measuring timing. (Convection cooking)
12 P56 IN Terminal not used.
13 P55 OUT Timing signal output terminal for temperature measurement(OVEN THERMIS-
TOR).
"H" level (GND) : Thermistor OPEN timing.
"L" level (-5V) : Temperature measuring timing. (Convection cooking)
14-18 P54-P50 IN/OUT Terminal not used.
19 P47 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P70 - P73 terminal while
one of G8 line key on matrix is touched.
20 P46 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P70 - P73 terminal while
one of G7 line key on matrix is touched.
21 P45 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P70 - P73 terminal while
one of G6 line key on matrix is touched.
22 P44 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P70 - P73 terminal while
one of G5 line key on matrix is touched.
23 P43 OUT Signal to sound buzzer.
A: key touch sound.
B: Completion sound.
C: When the temperature of the oven cav-
ity reaches the preset temperature in
the preheating mode, or when the
preheating hold time (30 minutes) is
elapsed.
24 INT2 IN Signal to synchronized LSI with commercial power source frequency(60Hz).
This is basic timing for time processing of LSI.
25 P41 OUT Oven lamp and turntable motor driving signal(Square Waveform : 60Hz).
To turn on and off shut-off relay (RY6). The
square waveform voltage is delivered to
the relay (RY6) driving circuit.
A
B
C
H: GND
L
0.1 sec
2.0 sec
1.0 sec
1.0 sec
16.7 msec.
H : GND
L (-5V)
During cooking
L
H
16.7 msec.