105 lines
2.3 KiB
Arduino
105 lines
2.3 KiB
Arduino
|
// Basic demo for configuring the MCP4728 4-Channel 12-bit I2C DAC
|
||
|
|
#include <Adafruit_MCP4728.h>
|
||
|
|
#include <Wire.h>
|
||
|
|
|
||
|
|
Adafruit_MCP4728 mcp;
|
||
|
|
|
||
|
|
|
||
|
|
// 1 3 5 7 hexany log2
|
||
|
|
float tuning[22];
|
||
|
|
// bassline
|
||
|
|
//int pitch[] = { 1, 2, -1, 0, -1, 1, -1, 0, -1, 1, -1 };
|
||
|
|
//float dur[] = { 0.25, 0.25, 0.5, 0.25, 0.5, 0.25, 0.5, 0.25, 0.5, 0.25, 0.5 };
|
||
|
|
// kick
|
||
|
|
//int pitch[] = { 1, -1, 1, -1, 1, -1, 1, -1, 1 };
|
||
|
|
//float dur[] = { 0.25, 0.75, 0.25, 0.75, 0.25, 0.75, 0.25, 0.75};
|
||
|
|
int pitch[] = { 9, 7, 5, 3, 8, 6, 5, 3 };
|
||
|
|
float dur[] = { 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5 };
|
||
|
|
|
||
|
|
|
||
|
|
float gate = 0.25;
|
||
|
|
int bpm = 140;
|
||
|
|
int phrase = 8;
|
||
|
|
float beat_s = 60.0 / (float)bpm;
|
||
|
|
int beat_m = round(1000.0 * beat_s);
|
||
|
|
float voltrange = 4.85; // measured this, probably not accurate
|
||
|
|
float octave = 4096.0 / voltrange; // number of DAC steps in an octave
|
||
|
|
float mod_b = 3.141592653589793 / 4.0;
|
||
|
|
|
||
|
|
|
||
|
|
int s;
|
||
|
|
bool noteon = false;
|
||
|
|
long play_t;
|
||
|
|
long release_t;
|
||
|
|
long last_t;
|
||
|
|
long init_t;
|
||
|
|
|
||
|
|
|
||
|
|
void setup(void) {
|
||
|
|
Serial.begin(115200);
|
||
|
|
while (!Serial)
|
||
|
|
delay(10); // will pause Zero, Leonardo, etc until serial console opens
|
||
|
|
|
||
|
|
if (!mcp.begin(0x64)) {
|
||
|
|
Serial.println("Failed to find MCP4728 chip");
|
||
|
|
while (1) {
|
||
|
|
delay(10);
|
||
|
|
}
|
||
|
|
Serial.println("MCP4728 initialised");
|
||
|
|
}
|
||
|
|
|
||
|
|
mcp.setChannelValue(MCP4728_CHANNEL_B, 0);
|
||
|
|
|
||
|
|
float n0 = 0;
|
||
|
|
for( int i = 0; i < 22; i++ ) {
|
||
|
|
tuning[i] = round(n0 + octave * (float)i / 7.0);
|
||
|
|
}
|
||
|
|
|
||
|
|
s = 0;
|
||
|
|
release_t = 0;
|
||
|
|
play_t = 0;
|
||
|
|
last_t = millis();
|
||
|
|
init_t = last_t;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
void loop() {
|
||
|
|
long now = millis();
|
||
|
|
if( noteon ) {
|
||
|
|
if( now - last_t > release_t ) {
|
||
|
|
noteOff();
|
||
|
|
last_t = now;
|
||
|
|
play_t = round(beat_m * dur[s] * (1.0 - gate));
|
||
|
|
noteon = false;
|
||
|
|
s += 1;
|
||
|
|
if( s == phrase ) {
|
||
|
|
s = 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
if( now - last_t > play_t ) {
|
||
|
|
noteOn(pitch[s]);
|
||
|
|
last_t = now;
|
||
|
|
release_t = round(beat_m * dur[s] * gate);
|
||
|
|
noteon = true;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// sychronise this better
|
||
|
|
long mod_t = (now - init_t);
|
||
|
|
float mod = 0.5 + 0.5 * sin(mod_b * (float)mod_t / (float)beat_m);
|
||
|
|
mcp.setChannelValue(MCP4728_CHANNEL_C, round(4095.0 * mod));
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void noteOn(int note) {
|
||
|
|
if( note > -1 ) {
|
||
|
|
mcp.setChannelValue(MCP4728_CHANNEL_A, tuning[note]);
|
||
|
|
mcp.setChannelValue(MCP4728_CHANNEL_B, 4095);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void noteOff() {
|
||
|
|
mcp.setChannelValue(MCP4728_CHANNEL_B, 0);
|
||
|
|
}
|