89 lines
1.6 KiB
C++
89 lines
1.6 KiB
C++
// can fibomod make an interesting noise?
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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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#define nsamp 256
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#define dacmax 256
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unsigned int phase = 0;
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unsigned int fibo = 20;
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unsigned int scale = 0;
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byte waveform[nsamp];
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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 prescaler
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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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Serial.begin(115200);
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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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mcp.setSpeed(800000L);
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for( int i = 0; i < nsamp; i++ ) {
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waveform[i] = 1;
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}
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}
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ISR(TIMER1_COMPA_vect){//timer1
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unsigned int flog;
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scale = 10;
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fibo = 3 + analogRead(A0) >> 2;
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flog = fibo;
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while( flog ) {
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flog = flog >> 1;
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scale -= 1;
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}
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Serial.println(fibo);
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Serial.println(scale);
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Serial.println(fibo << scale);
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}
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void loop() {
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int p0 = phase - 1;
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int p1 = phase + 2;
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if( p0 < 0 ) {
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p0 += nsamp;
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}
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if( p1 < 0 ) {
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p1 += nsamp;
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}
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waveform[phase] = (waveform[p1] + waveform[p0]) % fibo;
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mcp.fastWrite(waveform[phase] << scale, 0, 0, 0);
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phase += 1;
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if( phase >= nsamp ) {
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phase = 0;
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}
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}
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