#include <SPI.h>
#define CS 17
#define LDAC 16
SPISettings MCP4922(20000000,MSBFIRST,SPI_MODE0);
void setup() {
  Serial.begin(115200);
  pinMode(CS, OUTPUT);
  pinMode(LDAC, OUTPUT);
  
  SPI.begin();
  SPI.beginTransaction(MCP4922);
  digitalWrite(CS, LOW);
}

bool statelight = true;
int timetick = 0;
int real;
int mode_int = -1;
void loop() {
  
  real = millis();
  if(Serial.available() > 0)
    {
      String mode = Serial.readString();
       mode_int = mode.toInt();
    }
    if(mode_int == 1)
    {
      if(real - timetick >= 1000)
      {
        timetick = real;
        digitalWrite(CS,statelight);
        SPI.transfer16(0x9800);
        SPI.transfer16(0x39c3);
        statelight = !statelight;
      }
      // digitalWrite(LDAC, LOW);
      // Serial.println("Running");
      // digitalWrite(2, statelight);
      // statelight = !statelight;
    }
    else if(mode_int == 0)
    {
      digitalWrite(CS, LOW);
      SPI.transfer16(0x9800);
      SPI.transfer16(0x39c3);

      // Serial.println("Close light");
      // digitalWrite(2, LOW);
    }
    
}