Port to lora_isp4520 board

src/buzz/buzz.cpp

@@ -0,0 +1,52 @@
+#include "buzz.h"
+#include "configuration.h"
+
+#ifdef NRF52_SERIES
+#include "variant.h"
+#endif
+
+#ifndef PIN_BUZZER
+
+void playBeep(){};
+void playStartMelody(){};
+void playShutdownMelody(){};
+
+#else
+#include "Tone.h"
+#include "pitches.h"
+
+extern "C" void delay(uint32_t dwMs);
+
+struct ToneDuration {
+  int frequency_khz;
+  int duration_ms;
+};
+
+const int DURATION_1_8 = 125;  // 1/8 note
+const int DURATION_1_4 = 250;  // 1/4 note
+
+void playTones(const ToneDuration *tone_durations, int size) {
+  for (int i = 0; i < size; i++) {
+    const auto &tone_duration = tone_durations[i];
+    tone(PIN_BUZZER, tone_duration.frequency_khz, tone_duration.duration_ms);
+    // to distinguish the notes, set a minimum time between them.
+    delay(1.3 * tone_duration.duration_ms);
+  }
+}
+
+void playBeep() { tone(PIN_BUZZER, NOTE_B3, DURATION_1_4); }
+
+void playStartMelody() {
+  ToneDuration melody[] = {{NOTE_B3, DURATION_1_4},
+                           {NOTE_B3, DURATION_1_8},
+                           {NOTE_B3, DURATION_1_8}};
+  playTones(melody, sizeof(melody) / sizeof(ToneDuration));
+}
+
+void playShutdownMelody() {
+  ToneDuration melody[] = {{NOTE_B3, DURATION_1_4},
+                           {NOTE_G3, DURATION_1_8},
+                           {NOTE_D3, DURATION_1_8}};
+  playTones(melody, sizeof(melody) / sizeof(ToneDuration));
+}
+#endif