Datasheet

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6.10. Potentiometer
A single turn potentiometer is connected to the ADC channel AN4 (CPU pin 52) of the microcontroller. This may be used
to vary the input analog voltage value to this pin between 3V3A and Ground.
Note: The potentiometer is fitted to offer an easy way of supplying a variable analog input to the controller. It does not
necessarily reflect the accuracy of the controllers ADC. Please see the device manual for details.
6.11. Infrared Emitter & Detector
An infrared emitter (IR-LED, part TSKS5400S) and infrared detector (IR-DET, part TSOP98238) are included on the
RDK. The IR emitter is designed to use the burst capabilities of the RL78 Clock/Buzzer Output (PCLBUZ0) and is output
on CPU pin 64. The IR detector can be used with either the TI03 or INTP4 interfaces on the RL78 to detect IR bursts on
CPU pin 21.
Note: These IR emitter and IR detector are positioned close together on the board. The detector will receive the output of
the emitter.
6.12. TRIAC
A Renesas Triac, Q2 (Part number: BCR3AS-12A) designed for low power use is included on the RDK. The Triac can be
turned ON by an I/O pin of the CPU to control an AC load. The Triac connections are to be in series with a low-voltage
AC source (48VAC RMS Maximum) and a load at J3 between 1 &3, as shown in the schematic below. It can turn the
load ON and OFF but is not intended for dimming or proportional (phase) control. When the MCU pin 30 is set to HIGH,
the transistor Q6 is turned on, which turns on the input of the opto-coupler. The opto-coupler output allows current to
flow to the Gate of Q2. Resistor R10, 360 ohm, limits current to the Triac Gate. When the load is turned ON, as MCU
Pin 30 is set to HIGH, LED8 will turn on at the same time.
The below is an example of a connection diagram when a light bulb is connected as a load.
Note: DO NOT USE LINE VOLTAGE! For safety, an isolation transformer is required.