// Basic demo for configuring the MCP4728 4-Channel 12-bit I2C DAC
#include <Adafruit_MCP4728.h>
#include <Wire.h>

Adafruit_MCP4728 mcp;


int tuning[15];
int edo = 7;
int sequence[] = { 0, 0, 3, 0, 5, 0, 7, 2, 0, 0, 3, 0, 5, 0, 7, 6 };
float voltrange = 5.0;  // measured this, probably not accurate
float octave = 4096.0 / voltrange; // number of DAC steps in an octave




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 < 15; i++ ) {
      tuning[i] = round(n0 + octave * (float)i / (float)edo);
      Serial.println(tuning[i]);
  }
  
}


void loop() {
  for( int i = 0; i < 16; i++ ) {
    note(sequence[i], 250);
  }
}


void note(int note, int dur) {
  int pot = analogRead(A0);
  float gate = (float)pot / 1024.0;

  mcp.setChannelValue(MCP4728_CHANNEL_A, tuning[note]);
  mcp.setChannelValue(MCP4728_CHANNEL_B, 4095);
  delay(round(gate * (float)dur));
  mcp.setChannelValue(MCP4728_CHANNEL_B, 0);
  delay(round((1 - gate) *  (float)dur)); 
}