Feature: Embedded design


Figure 3: Output waveform, as seen on an oscilloscope


to generate a sine wave with a frequency of 1kHz and an amplitude of 2.5V; see Figure 2. Te program demonstrates the simplicity of generating a waveform using the UNO R4 series together with the built-in DAC. Figure 2 shows the program listing. At the beginning of the


program, AnalogWave header file is included in the program and the frequency is set to 1kHz (100Hz). Te amplitude multiplier is set to 0.5 so that the peak-to-peak amplitude of the generated waveform will be 5 × 0.5 = 2.5V (notice that the DAC reference voltage is not exactly +5V, it is slightly lower). Inside the setup() function, the amplitude is set and sine


waveform is generated. Figure 3 shows the waveform on a digital oscilloscope. In this figure, the vertical scale was 1V/division, and the horizontal scale was 500μs/division. Te frequency is 1kHz, and the amplitude is about 2.5V, as expected.


// ========================================== //


// Tis program generates sine wave with frequency 1 kHz and amplitude 2.5 V //


// Author: Sami Spiteri // File : Sinewave // Date


: July, 2025


//=========================================== #include "analogWave.h"


analogWave wave(DAC); int freq = 1000;


float amplitude = 0.5;


void setup() {


wave.amplitude(amplitude); // Set Amplitude wave.sine(freq);


} void loop() { }


Figure 2: Program listing


Notice that in the above program, the default DAC resolution of 8 bits was used. Te DAC resolution can be changed to 12 bits to improve the waveform:


void setup() { analogWriteResolution(12); // Change to 12-bits wave.amplitude(amplitude); // Set Amplitude wave.sine(freq); }


// Generate sine wave


// Set freq = 1 kHz // Set Amplitude multiplier


// Generate sine wave


www.electronicsworld.co.uk December 2025/January 2026 33


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