User`s manual

DemoKit-LG2 User’s Manual

9. Sample Project

The DemoKit-LG2 sample program resides in a single directory called main-directory, which contains

all of the output files for NEC Electronics’ integrated development environment (IDE).

The main directory contains the workspace and project files. All source files and associated files are

located in the directory. The workspace file is named DemoKit-LG2.prw is provided to demonstrate

the 78K0/LG2 MCU’s functionality.

9.1 Real-Time Clock

This part of the sample project realizes a real-time clock. After the program initializes, the watch timer

generates an exact clock reference based on the 32.768 kHz subclock and the LCD displays the time in

either 24-hour or AM/PM clock format, depending on the setting selected.

9.2 Temperature Measurement

Temperature is measured using the dual-slope method to convert the temperature sensor’s resistor value

into a digital counter-value. To do this, the MCU 16-bit timer/event counter 00 measures the charging

time of the C

18 capacitor. The first charging slope uses a reference resistor (RREF = R6) and the second a

variable resistor (R

VAR= R5 + RT), which should be determined. The variable resistor of the temperature

sensor, and consequently the temperature, can be calculated by comparing the two measured times and

the known R

REF reference resistor. The LCD displays the temperature in degrees Celsius or degrees

Fahrenheit, depending on the setting selected. Additionally, the temperature is transferred via UART6 at

the default data transfer speed of 115200 bits per second to a terminal program running on the host

computer.

9.3 Light Incidence Measurement

This part of the sample project measures light incidence. The MCU’s A/D converter (channel 0) is used

to measure a voltage cycle at the phototransistor and the result is converted into a percent value and

displayed on the LCD.

9.4 Buzzer Output Example

This demonstration drives the buzzer by using the 16-bit timer/event counter 01. The timer is

configured to generate a rectangular waveform. By changing the output frequency of the timer, the

buzzer can generate different tones. For demonstration purposes, a simple melody is played.

9.5 Menu Selection

To shift between the different operating modes of the sample project, follow the menu configuration

shown in Figure 64. The first column shows the main menus and the second the sub-menus. Move SW3

up or down to switch from one menu to another and from left to right to switch between sub-menus.