85 lines
2.6 KiB
C++
85 lines
2.6 KiB
C++
#include "AudioThread.h"
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#include "SharedState.h"
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#include <I2S.h>
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#include <math.h>
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// I2S Pin definitions
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// You may need to change these to match your hardware setup (e.g., for a specific DAC).
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const int I2S_BCLK_PIN = 9; // Bit Clock (GP9)
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const int I2S_LRC_PIN = 10; // Left-Right Clock (GP10)
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const int I2S_DOUT_PIN = 11; // Data Out (GP11)
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// Audio parameters
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const int SAMPLE_RATE = 44100;
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const int16_t AMPLITUDE = 16383; // Use a lower amplitude to avoid clipping (max is 32767 for 16-bit)
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// Create an I2S output object
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I2S i2s(OUTPUT);
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// --- Synthesizer State ---
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float currentFrequency = 440.0f;
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double phase = 0.0;
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unsigned long lastNoteChangeTime = 0;
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// ---
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void setupAudio() {
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// Configure I2S pins
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i2s.setBCLK(I2S_BCLK_PIN);
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i2s.setDATA(I2S_DOUT_PIN);
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// Set the sample rate and start I2S communication
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i2s.setFrequency(SAMPLE_RATE);
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if (!i2s.begin()) {
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Serial.println("Failed to initialize I2S!");
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while (1); // Halt on error
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}
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// Seed the random number generator from an unconnected analog pin
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randomSeed(analogRead(A0));
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}
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void loopAudio() {
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unsigned long now = millis();
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// Every 500ms, pick a new random note to play
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if (now - lastNoteChangeTime > 500) {
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lastNoteChangeTime = now;
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int noteIndex = random(0, SCALES[currentScaleIndex].numNotes);
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// Calculate frequency based on key, scale, and octave
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const float baseFrequency = 261.63f; // C4
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float keyFrequency = baseFrequency * pow(2.0f, currentKeyIndex / 12.0f);
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int semitoneOffset = SCALES[currentScaleIndex].semitones[noteIndex];
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currentFrequency = keyFrequency * pow(2.0f, semitoneOffset / 12.0f);
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Serial.println("Playing note: " + String(currentFrequency) + " Hz");
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}
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// Generate the sine wave sample
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int16_t sample;
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double phaseIncrement = 2.0 * M_PI * currentFrequency / SAMPLE_RATE;
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phase = fmod(phase + phaseIncrement, 2.0 * M_PI);
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switch (currentWavetableIndex) {
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case 0: // Sine
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sample = static_cast<int16_t>(AMPLITUDE * sin(phase));
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break;
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case 1: // Square
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sample = (phase < M_PI) ? AMPLITUDE : -AMPLITUDE;
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break;
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case 2: // Saw
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sample = static_cast<int16_t>(AMPLITUDE * (1.0 - (phase / M_PI)));
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break;
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case 3: // Triangle
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sample = static_cast<int16_t>(AMPLITUDE * (2.0 * fabs(phase / M_PI - 1.0) - 1.0));
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break;
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default:
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sample = 0;
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break;
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}
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// Write the same sample to both left and right channels (mono audio).
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// This call is blocking and will wait until there is space in the DMA buffer.
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i2s.write(sample);
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i2s.write(sample);
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} |