#include <Plaquette.h>

// Buzzer.
DigitalOut buzzer(12);

// Tone generating wave.
SquareWave toneWave;

// Ramp that changes frequency.
Ramp toneRamp;

void begin() {
  // Start ramp.
  toneRamp.go(80, 1000, 10);
}

void step() {
  // When ramp finished: restart.
  if (toneRamp.isFinished())
    toneRamp.start();
  
  // Adjust frequency.
  toneWave.frequency(toneRamp);

  // Send to output.
  toneWave >> buzzer;
}