arduino-modular/Noisemakers/Noisemakers.ino

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2024-01-21 05:37:01 +00:00
// Very basic Karplus-Strong
// based on this explanation http://sites.music.columbia.edu/cmc/MusicAndComputers/chapter4/04_09.php
#include <Adafruit_MCP4728.h>
#include <Wire.h>
Adafruit_MCP4728 mcp;
#define nsamp 128
#define dacmax 256
unsigned int phase;
unsigned int repeats;
void setup() {
cli();
//set timer1 interrupt at 1Hz
TCCR1A = 0;// set entire TCCR1A register to 0
TCCR1B = 0;// same for TCCR1B
TCNT1 = 0;//initialize counter value to 0
// set compare match register for 1hz increments
//OCR1A = 15624;// = (16*10^6) / (1*1024) - 1 (must be <65536)
//OCR1A = 7812;// = (16*10^6) / (1*1024) - 1 (must be <65536)
OCR1A = 1952;
// turn on CTC mode
TCCR1B |= (1 << WGM12);
// Set CS10 and CS12 bits for 1024 prescaler
TCCR1B |= (1 << CS12) | (1 << CS10);
// enable timer compare interrupt
TIMSK1 |= (1 << OCIE1A);
sei();
Serial.begin(115200);
if (!mcp.begin(0x64)) {
while (1) {
delay(100);
}
}
// mcp.setSpeed(400000L);
// mcp.setSpeed(800000L);
mcp.setSpeed(800000L);
randomSeed(analogRead(A0));
phase=0;
}
byte waveform[nsamp];
void pluck(){
for (int i=0; i<nsamp; ++i){
waveform[i]=random(256);
}
}
void loop() {
byte s1, s2;
int p0 = phase;
s1 = waveform[phase];
phase += 1;
if( phase > nsamp ) {
phase = 0;
}
s2 = waveform[phase];
waveform[p0] = ( s1 & s2 ) + ((s1 ^ s2) >> 1);
mcp.fastWrite(s1 << 4, 0, 0, 0);
}
ISR(TIMER1_COMPA_vect){//timer1 interrupt 1Hz
pluck();
}