169 lines
4.9 KiB
C++
169 lines
4.9 KiB
C++
// We Wish You a Merry Christmas
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#include <Adafruit_MCP4728.h>
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#include <Wire.h>
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Adafruit_MCP4728 mcp;
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float tuning[16];
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// 0 = A, 8 = F (tonic)
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int m1[] = { 3, 8, 8, 10, 8, 7, 5, 5, 5, 10, 10, 12, 10, 8, 7, 3, 7, 12, 12, 13, 12, 10, 8, 5, 3, 3, 5, 10, 7, 8, 3, 8, 8, 8, 7, 7, 8, 7, 5, 3, 10, 12, 10, 10, 8, 8, 15, 3, 3, 3, 5, 10, 7, 8 };
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int s1[] = { 0, 2, 4, 5, 6, 7, 8, 10, 12, 14, 16, 17, 18, 19, 20, 22, 24, 26, 28, 29, 30, 31, 32, 34, 36, 37, 38, 40, 42, 44, 48, 50, 52, 54, 56, 60, 62, 64, 66, 68, 72, 74, 76, 77, 78, 79, 80, 82, 84, 85, 86, 88, 90, 92 };
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float d1[] = { 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 4 };
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int m2[] = { 8, 1, 2, 3, 4, 5, 0, 1, 3, 8, 8, 3, 5, 7, 8, 7, 0, 1, 3, 8 };
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int s2[] = { 2, 8, 14, 20, 26, 32, 36, 38, 42, 44, 50, 56, 62, 68, 74, 80, 84, 86, 90, 92 };
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float d2[] = { 6, 6, 6, 6, 6, 4, 2, 4, 2, 6, 6, 6, 6, 6, 6, 4, 2, 4, 2, 4 };
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// int m1[] = { 0, 2, 4, 5, 7, 9, 11, 12 };
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// int s1[] = { 0, 2, 4, 6, 8, 10, 12, 14 };
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// float d1[] = { 1.0, 0.5, 1.0, 0.5, 1.0, 0.5, 1.0, 0.5 };
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// int m2[] = { 0, 4, 7, 12, 0, 4, 7, 12, 0, 4, 7, 12, 0, 4, 7, 12 };
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// int s2[] = { 0, 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
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// float d2[] = { 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5 };
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float gate = 0.5;
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int bpm = 320;
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float beat_s = 60.0 / (float)bpm;
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int beat = round(1000.0 * beat_s);
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// count_in = number of beats since t0 to wait before we startt playing
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// repeat = number of beats to repeat - could be computed from the sequence data
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// From here on, all times are in milliseconds to head off floating point errors
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long count_in = 4 * beat;
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int repeat = 96;
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float voltrange = 5.0;
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float octave = 4096.0 / voltrange; // number of DAC steps in an octave
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float mod_b = 3.141592653589793 / 4.0;
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typedef struct {
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int s = -1;
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bool playing = false;
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bool looped = false;
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long play = 0;
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long rel = 0;
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long last = 0;
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long init = 0;
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int *melody;
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int *start;
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float *duration;
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int len = 0;
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MCP4728_channel_t pitch;
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MCP4728_channel_t gate;
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} sequencer;
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sequencer seq1, seq2;
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long start_time;
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void setup(void) {
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Serial.begin(115200);
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while (!Serial)
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delay(10); // will pause Zero, Leonardo, etc until serial console opens
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if (!mcp.begin(0x64)) {
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Serial.println("Failed to find MCP4728 chip");
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while (1) {
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delay(10);
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}
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Serial.println("MCP4728 initialised");
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}
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float n0 = 0;
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for( int i = 0; i < 16; i++ ) {
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tuning[i] = round(n0 + octave * (float)i / 12.0);
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}
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long now = millis();
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start_time = now;
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seq1.last = now;
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seq1.pitch = MCP4728_CHANNEL_A;
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seq1.gate = MCP4728_CHANNEL_B;
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seq1.melody = m1;
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seq1.start = s1;
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seq1.duration = d1;
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seq1.len = sizeof(m1) / sizeof(m1[0]);
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times_to_ms(seq1);
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seq2.last = now;
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seq2.pitch = MCP4728_CHANNEL_C;
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seq2.gate = MCP4728_CHANNEL_D;
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seq2.melody = m2;
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seq2.duration = d2;
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seq2.start = s2;
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seq2.len = sizeof(m2) / sizeof(m2[0]);
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times_to_ms(seq2);
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}
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void times_to_ms(sequencer& seq) {
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for( int i = 0; i < seq.len; i++ ) {
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seq.start[i] *= beat;
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seq.duration[i] = (float)beat * seq.duration[i] * 0.8;
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}
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}
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void loop() {
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long now = millis();
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long t = now - start_time;
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long beats = -1;
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if( t >= count_in ) {
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beats = (t - count_in) % (beat * repeat);
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runSequencer(seq1, t, beats);
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runSequencer(seq2, t, beats);
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}
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}
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void runSequencer(sequencer& seq, long now, long beats) {
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int next = seq.s + 1;
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int start;
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if( seq.playing ) {
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if( now > seq.rel ) {
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mcp.setChannelValue(seq.gate, 0);
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seq.playing = false;
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}
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}
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if( next > seq.len - 1 ) {
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seq.s = -1;
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seq.looped = true;
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return; // don't start the loop yet
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} else {
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start = seq.start[next];
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}
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if( seq.looped ) { // reached the end and waiting for the start of the bar
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if( beats < seq.last ) {
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seq.looped = false; // bar has restarted, start waiting
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seq.s = -1;
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next = 0;
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} else {
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return;
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}
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}
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seq.last = beats;
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if( beats >= start ) {
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seq.s = next;
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seq.rel = now + seq.duration[seq.s];
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if( seq.melody[seq.s] > -1 ) {
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mcp.setChannelValue(seq.pitch, tuning[seq.melody[seq.s]]);
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mcp.setChannelValue(seq.gate, 4095);
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}
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seq.playing = true;
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}
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}
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