snapshot

libraries/audio-tools/examples/examples-dsp/examples-mozzi/control_gain/control_gain.ino

@@ -0,0 +1,52 @@
+/**
+ * Demo how to use the Mozzi API to provide a stream of int16_t data.
+ * Inspired by https://sensorium.github.io/Mozzi/examples/#01.Basics
+ */
+#include "AudioTools.h"
+#include "AudioTools/AudioLibs/AudioBoardStream.h"
+#include "AudioTools/AudioLibs/MozziStream.h"
+#include <Oscil.h>                // oscillator template
+#include <tables/sin2048_int8.h>  // sine table for oscillator
+
+const int sample_rate = 16000;
+AudioInfo info(sample_rate, 1, 16);
+AudioBoardStream i2s(AudioKitEs8388V1);  // audio sink
+MozziStream mozzi; // audio source
+StreamCopy copier(i2s, mozzi); // copy source to sink
+// use: Oscil <table_size, update_rate> oscilName (wavetable), look in .h file
+// of table #included above
+Oscil<SIN2048_NUM_CELLS, sample_rate> aSin(SIN2048_DATA);
+// control variable, use the smallest data size you can for anything used in
+// audio
+byte gain = 255;
+
+void setup() {
+  Serial.begin(115200);
+  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Info);
+
+  // setup mozzi
+  auto cfg = mozzi.defaultConfig();
+  cfg.control_rate = CONTROL_RATE;
+  cfg.copyFrom(info);
+  mozzi.begin(cfg);
+
+  // setup output
+  auto out_cfg = i2s.defaultConfig();
+  out_cfg.copyFrom(info);
+  i2s.begin(out_cfg);
+
+  // setup mozzi sine
+  aSin.setFreq(3320);  // set the frequency
+}
+
+void loop() { copier.copy(); }
+
+void updateControl() {
+  // as byte, this will automatically roll around to 255 when it passes 0
+  gain = gain - 3;
+}
+
+AudioOutputMozzi updateAudio() {
+  return (aSin.next() * gain) >>
+         8;  // shift back to STANDARD audio range, like /256 but faster
+}