monoseq.pde

/*
Adapted from denkitribe's code, which can be found here:
http://code.google.com/p/denkitribe/source/browse/trunk/Arduino/MonotronCVGateTest/MonotronCVGateTest.pde

pin setup: - DAC 1  --->  Arduino +5V
           - DAC 2  --->  Arduino 10
           - DAC 3  --->  Arduino 13
           - DAC 4  --->  Arduino 11
           - DAC 5  --->  Gnd
           - DAC 6  --->  Not Connected
           - DAC 7  --->  Arduino Gnd
           - DAC 8  --->  CV Out
           
For information on why the pins are configured this way see the links below:

MCP4822 datasheet - http://ww1.microchip.com/downloads/en/devicedoc/21953a.pdf
SPI library - http://www.arduino.cc/playground/Code/Spi
*/

#include <SPI.h>

const int SS_PIN = 10; //SPI select slave pin
const int gatePin = 2;

void setup () {
  pinMode(SS_PIN, OUTPUT);
  SPI.begin();
}

void sendNote (int key) {
  int pitch = 0xa00l * key / 12; //divide by 12 to map to one octave
  
  digitalWrite(SS_PIN, LOW); //DAC is selected when LOW
  SPI.transfer(0x10 + (pitch >> 8));
  SPI.transfer(pitch & 0xff);
  digitalWrite(SS_PIN, HIGH); //Deselect DAC
  
  digitalWrite(gatePin, HIGH); //send gate signal
  delay(90);
  digitalWrite(gatePin, LOW); //stop sending gate signal
  delay(10);
}

void loop () {
  sendNote(0);
  sendNote(12);
  sendNote(11);
  sendNote(12);
  sendNote(16);
  sendNote(12);
  sendNote(11);
  sendNote(12);

  sendNote(0);
  sendNote(12);
  sendNote(10);
  sendNote(12);
  sendNote(16);
  sendNote(12);
  sendNote(10);
  sendNote(12);

  sendNote(0);
  sendNote(12);
  sendNote(9);
  sendNote(12);
  sendNote(16);
  sendNote(12);
  sendNote(9);
  sendNote(12);

  sendNote(0); 
  sendNote(12);
  sendNote(8);
  sendNote(12);
  sendNote(16);
  sendNote(12);
  sendNote(8);
  sendNote(12);
}