#include <Arduino.h>

const int SCLK = 52;
const int nSYNC = 53;
const int DIN = 51;
const int nLDAC = 48;
const int CLR = 49;

// const int DIN = 30; 
// const int SCLK = 23;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  Serial.println("Hello, world!");

  pinMode(SCLK, OUTPUT);
  pinMode(nSYNC, OUTPUT);
  pinMode(DIN, OUTPUT);

  digitalWrite(nLDAC, LOW); 
  digitalWrite(CLR, LOW); 
}

void wirteDataLSB(uint8_t cmd, uint16_t data){
  uint32_t send_data; 
  digitalWrite(nLDAC, LOW); 
  digitalWrite(CLR, LOW); 
  send_data = cmd;
  send_data = send_data << 16; 
  send_data = send_data | data;  
  Serial.print(send_data, HEX); 
  Serial.print(" ");
  Serial.print(send_data, BIN);
  Serial.print(" ");

  digitalWrite(nSYNC, LOW);
  delay(100);
  for (int i = 0; i < 24; i++) {
    digitalWrite(DIN, send_data & 0x0001); 
    digitalWrite(SCLK, LOW);
    digitalWrite(SCLK, HIGH);
    send_data >>= 1;
    Serial.print(send_data & 0x0001);
    Serial.print(" ");
  }
  digitalWrite(nSYNC, HIGH);
  Serial.println("");
}

void wirteDataMSB(uint8_t cmd, uint16_t data){
  uint32_t send_data; 
  send_data = cmd;
  send_data = send_data << 16; 
  send_data = send_data | data;  
  Serial.print(send_data, HEX); 
  Serial.print(" ");
  Serial.print(send_data, BIN);
  Serial.print(" ");

  // for (int i = 24; i >= 0; i--){
  //   byte msb = (send_data >> i) & 0xFF;
  //   Serial.print(msb, BIN);
  // }
  bool msb = 0b0; 
  digitalWrite(nSYNC, LOW);
  for (int i = 23; i >= 0; i--){
    msb = bitRead(send_data, i);  
    digitalWrite(DIN, msb); 
    digitalWrite(SCLK, LOW);
    digitalWrite(SCLK, HIGH);
  }
  digitalWrite(nSYNC, HIGH);


  Serial.println("");
}

uint16_t data = 0x0000;
void loop() {
  // put your main code here, to run repeatedly:
  if (data >= 0xffff) {data = data - 0xf000; }
  else {data = data + 0x1073; }
  wirteDataMSB(0x1f,0x9999); 
  delay(10); 
}