/* digital to analog with MCP4922 */
/* P Chongstitvatana, 5 Apr 2020 */

int xCS = 8;
int xSCK = 9;
int xSDI = 10;
int xLDAC = 11;
int xSHDN = 12;

void setup(){
  pinMode(xCS, OUTPUT);
  pinMode(xSCK, OUTPUT);
  pinMode(xSDI, OUTPUT);
  pinMode(xLDAC, OUTPUT);
  pinMode(xSHDN, OUTPUT);
  
  digitalWrite(xCS, HIGH);
  digitalWrite(xSCK, LOW);
  digitalWrite(xSDI, LOW);
  digitalWrite(xLDAC, HIGH);
  digitalWrite(xSHDN, HIGH);
}

/* write to DAC channel A */
void writeDAC( unsigned int value){
  unsigned int data, hi, lo;
  digitalWrite(xCS,LOW);    /* enable MCP4922 */
  data = value |= 0x3000;   /* chan A */
  hi = (data >> 8) & 0xFF;
  lo = data & 0xFF;
  shiftOut(xSDI,xSCK,MSBFIRST,hi); /* MSB data */
  shiftOut(xSDI,xSCK,MSBFIRST,lo);  /* LBS */
  digitalWrite(xCS,HIGH);
  digitalWrite(xLDAC,LOW);
  digitalWrite(xLDAC,HIGH);
}

void loop(){
  writeDAC(2047);
  while(1);
}