Chapter 9. Touch Control Panel Assem; Outline Of Touch Control Panel; Description Of Lsi - Sharp R-402JW-T Service Manual

CHAPTER 9.
R402JWT
TOUCH CONTROL PANEL ASSEMBLY

[1] OUTLINE OF TOUCH CONTROL PANEL

The touch control section consists of the following units.
(1) Key Unit
(2) Control Unit (The Control Unit consists of Power Unit and LSI Unit).
The principal functions of these units and their related signals are
explained below.
1. Key Unit
The key unit is composed of a matrix, signals generated in the LSI are
sent to the key unit through P20-P27.
When a key pad is touched, a signal is completed through the key unit
and passed back to the LSI through P70, P71, P41 and P45 to perform
the function that was requested.
2. Control Unit
Control unit consists of LSI, reset circuit, indicator circuit, power
source circuit, relay circuit, buzzer circuit, synchronizing signal circuit
and back light circuit.
1) Reset Circuit
This circuit generates a signal which resets the LSI to the initial
state when power is supplied.
2) Indicator Circuit
This circuit consists of 17 segments and 4 common electrodes
using a Liquid Crystal Display.

[2] DESCRIPTION OF LSI

The I/O signal of the LSI are detailed in the following table.
Pin No. Signal I/O
1-2 VL2-VL1 IN
3-6 AN7-AN4 IN
7 AN3 IN
8 AN2 IN
9 AN1 IN
10 AN0 IN
11-13 P57-P55 OUT Terminal not used.
14 CNTR0 OUT
15 P53 OUT Terminal not used.
16 P52 OUT
17 P51 OUT Terminal not used.
Power source voltage input terminal.
Standard voltage for LCD.
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.
Terminal not used.
To input signal which communicates the door open/close information to LSI.
Door close "H" level signal (0V). Door open "L" level signal (-5V)
Terminal not used.
Terminal not used.
Signal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
Oven lamp, fan motor and turntable motor driving signal
To turn on and off shut off relay (RY1). The square wave-
form voltage is delivered to the RY1 driving circuit and
RY2 control circuit.
Service Manual
3) Power Source Circuit
This circuit generates voltage necessary in the control unit from the
AC line voltage.
In addition, the synchronizing signal is available in order to com-
pose a basic standard time in the clock circuit.
Symbol Voltage
VSS
4) Relay Circuit
A circuit to drive the magnetron, fan motor, turntable motor and light
the oven lamp.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit audible
sounds (key touch sound and completion sound).
6) Synchronizing Signal Circuit
The power source synchronizing signal is available in order to com-
pose a basic standard time in the clock circuit. It accompanies a
very small error because it works on commercial frequency.
7) Door Sensing Switch
A switch to "tell" the LSI if the door is open or closed.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes LD1- LD4).
9) Night Light Circuit
A circuit to drive the light emitting diode (LD10).
Description
9 – 1
Application
-5V LSI(IC1)
0.1 sec.
A
2.0 sec.
B
16.7 msec.
During cooking
R402JWT
H : GND
L : -5V
H : GND
L : -5V
H : GND
L : -5V