Arduino Code for DAC8568

DAC8568-Arduino

/*
DAC8568
http://www.mouser.com/ds/2/405/sbas430d-94281.pdf

Vout = (Din/(2^n))*Vref*Gain
Din is straight binary
0 <= Din <= 65535
n = 16
Gain = 2 
=> Vout = (Din/65536)*Vref*2
Internal reference must be enable (disabled by default)

Two modes of operation, static and flexible
In flexible mode, to always have internal reference powered on, write the following to DB register (32 bit)
0b0XXX1001XXXX101XXXXXXXXXXXXXXXXX  

Data Input Register
0b     0XXX             XXXX            XXXX       XXXX XXXX XXXX XXXX         XXXX
   Prefix Bits(4) Control Bits(4)  Addr. Bits (4)     Data Bits (16)     Feature Bits (4)
*/
#include <SPI.h>

const int syncPin = 10;
const unsigned int setVrefOut1 = 0b00001001; 
const unsigned int setVrefOut2 = 0b00001010;
const unsigned int setVrefOut3 = 0b00000000; 
const unsigned int setVrefOut4 = 0b00000000; 
unsigned int prefix = 0b0000; //shouldn't change
unsigned int control = 0b0011; //0b0010 = write and update all registers, 0b0011 write and update single register
unsigned int address = 0b0000; //channel A = 0b0000
unsigned int data = 0b0101101001011010;
unsigned int feature = 0b0000;
//long output = 0b00000000000000000000000000000000;
unsigned int one;
unsigned int two;
unsigned int three;
unsigned int four;

void setup() {
  // set the slaveSelectPin as an output:
  pinMode (syncPin, OUTPUT);
  // initialize SPI:
  SPI.setDataMode(SPI_MODE1);
  SPI.begin();
  delay(20);
  digitalWrite(syncPin,LOW);
  SPI.transfer(setVrefOut1);
  SPI.transfer(setVrefOut2); 
  SPI.transfer(setVrefOut3); 
  SPI.transfer(setVrefOut4); 
  digitalWrite(syncPin,HIGH);
}

void loop() {
  data = 0b1111111111111111;
  for (unsigned int address = 0; address<8; address++)
  {
  DAC8568Write(prefix, control, address, data, feature);
  delay(1000);
  }
  data = 0b0111111111111111;
  for (unsigned int address = 0; address<8; address++)
  {
  DAC8568Write(prefix, control, address, data, feature);
  delay(1000);
  }
  data = 0b0000000000000000;
  for (unsigned int address = 0; address<8; address++)
  {
  DAC8568Write(prefix, control, address, data, feature);
  delay(1000);
  }
}

void DAC8568Write(unsigned int prefix, unsigned int control, unsigned int address, unsigned int data, unsigned int feature) {
  // take the SS pin low to select the chip:
  
  //  send in the address and value via SPI:
  one = (prefix << 4)|control;
  two = (address << 4)|(data >>12);
  three = data >> 4;
  four = (data << 4)|feature;
  //output = (one<<24)|(two<<16)|(three<<8)|four;
  digitalWrite(syncPin,LOW);
  SPI.transfer(one);
  SPI.transfer(two);
  SPI.transfer(three);
  SPI.transfer(four);
  //SPI.transfer(address);
  //SPI.transfer(value);
  // take the SS pin high to de-select the chip:
  digitalWrite(syncPin,HIGH); 
}