93 lines
1.8 KiB
C++
93 lines
1.8 KiB
C++
// Triggering shaped envelopes
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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[37];
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float voltrange = 4.85; // measured this, probably not accurate
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float octave = 4096.0 / voltrange; // number of DAC steps in an octave
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//bool gates[] = { true, false, true, false, true, false, false, true };
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bool gates[] = { true, false, false, false, true, false, false, false };
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int freqs[8];
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int lpattern = 8;
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int note = 0;
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bool trigger = false;
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long t0 = 0;
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void setup() {
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cli();
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//set timer1 interrupt at 1Hz
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TCCR1A = 0;// set entire TCCR1A register to 0
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TCCR1B = 0;// same for TCCR1B
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TCNT1 = 0;//initialize counter value to 0
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// set compare match register for 1hz increments
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//OCR1A = 15624;// = (16*10^6) / (1*1024) - 1 (must be <65536)
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//OCR1A = 7812;// = (16*10^6) / (1*1024) - 1 (must be <65536)
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OCR1A = 10000;
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// turn on CTC mode
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TCCR1B |= (1 << WGM12);
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// Set CS10 and CS12 bits for 1024 escaler
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TCCR1B |= (1 << CS12) | (1 << CS10);
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// enable timer compare interrupt
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TIMSK1 |= (1 << OCIE1A);
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sei();
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if (!mcp.begin(0x64)) {
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while (1) {
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delay(100);
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}
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}
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randomSeed(analogRead(A0));
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mcp.setSpeed(800000L);
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for( int i = 0; i < 8; i++ ) {
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freqs[i] = random(10, 450);
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}
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trigger = true;
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}
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ISR(TIMER1_COMPA_vect){ // called once every note
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trigger = true;
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}
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void loop() {
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long now = millis();
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float f1;
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int gate;
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long freq;
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if( trigger ) {
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t0 = now;
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trigger = false;
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freq = freqs[note];
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gate = gates[note];
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note++;
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if( note == lpattern ) {
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note = 0;
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}
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}
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f1 = 0.5 - 0.5 * sin((float)(now - t0) / (float)1000.0);
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mcp.setChannelValue(MCP4728_CHANNEL_A, round(4095.0 * f1));
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mcp.setChannelValue(MCP4728_CHANNEL_B, gate ? 4095 : 0);
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}
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