Service manual

15
R-1210
R-1211
DESCRIPTION OF LSI
LSI
The I/O signal of the LSI is detailed in the following table.
Pin No. Signal I/O Description
1-2 VL2-VL1 IN Power source voltage input terminal.
Standard voltage for LCD.
3-6 AN7-AN4 IN Terminal to change cooking input according to the Model.
By using the A/D converter contained in the LSI, DC voltage in accordance with the
Model in operation is applied to set up its cooking constant.
7 AN3 OUT Back light circuit (Light emitting diodes) driving signal.
8 AN2 IN To input signal which communicates the door open/close information to LSI.
Door close “H” level signal (0V). Door open “L” level signal (-5V).
9 AN1 IN AH sensor input..
This input is an analog input terminal from the AH sensor circuit, and connected to the
A/D converter built into the LSI.
10 AN0 IN Used for initial balancing of the bridge circuit (absolute humidity sensor). This input is
an analog input terminal from the AH sensor circuit, and connected to the A/D converter
built into the LSI.
11-13 P57-P55 OUT Used for initial balancing of the bridge circuit (absolute humidity sensor).
14 CNTR0 OUT Signal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
15 P53 OUT Used for initial balancing of the bridge circuit (absolute humidity sensor).
16 P52 OUT Oven lamp, fan motor and turntable motor driving signal
To turn on and off shut off relay (RY1). The
square waveform voltage is delivered to the
RY1 driving circuit and RY2 control circuit.
17 P51 OUT Used for initial balancing of the bridge circuit (absolute humidity sensor).
18 P50 OUT Terminal not used.
19 P47 OUT Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY2). The
signals holds “L” level during microwave
cooking and “H” level while not cooking. In
other cooking modes (variable cooking) the
signal turns to “H” level and “L” level in
repetition according to the power level.
20 P46 IN Signal coming from touch key.
When either G12 line on key matrix is touched, a corresponding signal out of P20 - P27
will be input into P46. When no key is touched, the signal is held at “H” level.
21 P45 IN Signal similar to P46.
When either G11 line on key matrix is touched, a corresponding signal will be input into P45.
22 P44 IN Signal similar to P46.
When either G10 line on key matrix is touched, a corresponding signal will be input into P44.
23 P43 IN Signal similar to P46.
When either G9 line on key matrix is touched, a corresponding signal will be input into P43.
24 INT0 IN Signal synchronized with commercial power source frequency.
This is the basic timing for time processing of LSI.
A
B
0.1 sec.
2.0 sec.
H : GND
L : -5V
H : GND
L : -5V
16.7 msec.
During cooking
H : GND
L : -5V
Maximum
output
70% of maximum
output
H : GND
L : -5V
H : GND
L : -5V
ON
ON
OFF
OFF OFF
24 sec.
8 sec.
16.7 msec.
H : GND
L : -5V