/*
  Blink
 Turns on an LED on for one second, then off for one second, repeatedly.
 
 This example code is in the public domain.
 */

#define SEARCH_ROM_CMD 0xF0
#define READ_ROM_CMD 0x33
#define MATCH_ROM_CMD 0x55
#define SKIP_ROM_CMD 0xCC
#define ALARM_SEARCH_CMD 0xEC
#define CONVERT_CMD 0x44
#define WRITE_SCRATCHPAD_CMD 0x4E
#define READ_SCRATCHPAD_CMD 0xBE
#define COPY_SCRATCHPAD_CMD 0x48
#define RECALL_E2_CMD 0xB8
#define READ_POWER_SUPPLY_CMD 0xB4

int one_wire = 2;
unsigned long last_temp;
int temp = 0;
int led = 13;
int error;


void report_error() {
  digitalWrite(led, HIGH);
}

int write_1_wire(int bus, unsigned char data) 
{
  unsigned char tmp = data;
  for (int i = 0; i < 8; i++) {
    pinMode(bus, OUTPUT);
    if ((tmp & 0x1) == 1) {
      // Write 1
      digitalWrite(bus, LOW);
      delayMicroseconds(3);
      pinMode(bus, INPUT);

    } 
    else {    
      digitalWrite(bus, LOW);
    }
    delayMicroseconds(60);
    pinMode(bus, INPUT);
    tmp = tmp >> 1;
  }
  return 1;
}

int read_1_wire(int bus, unsigned char *data) 
{
  unsigned char tmp = 0, tmp_bus;
  int time_start, time_stop;
  for (int i = 0; i < 8; i++) {
    pinMode(bus, OUTPUT);
    digitalWrite(bus, LOW);
    delayMicroseconds(1);
    pinMode(bus, INPUT);
    tmp_bus = digitalRead(bus);
    if (tmp_bus == HIGH) {
      tmp = tmp | (1 << i);
    } 
    delayMicroseconds(50);
  }
  *data = tmp;
  return 1;
}


// 1-wire init transaction
int init_1_wire(int bus)
{
  unsigned long read_time = 0, active = 0;
  pinMode(bus, OUTPUT);
  digitalWrite(bus, LOW);
  delayMicroseconds(500);
  pinMode(bus, INPUT);
  read_time=micros();
  while((micros()-read_time) < 500) {
    if (digitalRead(bus) == LOW) {
      active = 1;
    }
  }
  if (active == 0) {
    Serial.print("No pulse sensed\r\n");
    report_error();
    return -1;
  }
  return 1;
}

int rom_1_wire_single(int bus)
{
  unsigned char dev_id[8];
  if (write_1_wire(bus,SKIP_ROM_CMD) == -1) {
    report_error(); 
    return -1;
  }
  #if 0
  for (int i = 0; i < 8; i++) {
    if(read_1_wire(bus, &dev_id[i]) == -1) {
      report_error();
      return -1;
    }
  }
  for (int i = 0; i < 8; i++) {
    Serial.print("ID : ");
    Serial.print(dev_id[i], HEX);
    Serial.print("\r\n");
  }
  #endif
  return 1;
}

int wait_1_wire(int bus)
{
  int tmp = LOW;
  while (1){
    pinMode(bus, OUTPUT);
    digitalWrite(bus, LOW);
    delayMicroseconds(1);
    pinMode(bus, INPUT);
    tmp = digitalRead(bus);
    if (tmp == HIGH) {
      break;
    }
    delayMicroseconds(60);
  }
  return 1;
}


// the setup routine runs once when you press reset:
void setup() {                
  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);          
  pinMode(one_wire, INPUT);   
  Serial.begin(9600);
  last_temp = millis() + 5000;
  pinMode(13, OUTPUT);
}

// the loop routine runs over and over again forever:
void loop() {
  if ((millis() - last_temp) >= 2000) {
    unsigned char scratch[9];
    unsigned int tmp_int, tmp_dec;
    error = init_1_wire(one_wire);
    error = rom_1_wire_single(one_wire);
    error = write_1_wire(one_wire, CONVERT_CMD);
    last_temp = millis();
    while ((millis() - last_temp) < 1000);
    
    error = wait_1_wire(one_wire);
    error = init_1_wire(one_wire);
    error = rom_1_wire_single(one_wire);
    error = write_1_wire(one_wire,READ_SCRATCHPAD_CMD);
    for (int i = 0; i < 9; i++) {
      read_1_wire(one_wire, &scratch[i]); 
    }
    tmp_int = scratch[1];
    tmp_int <<= 8;
    tmp_int |= scratch[0];
    tmp_int >>= 4;
    tmp_dec = 0;
    if (scratch[0] & 0x8) {
      tmp_dec+=5000;
    }
    if (scratch[0] & 0x4) {
      tmp_dec+=2500;
    }
    if (scratch[0] & 0x2) {
      tmp_dec+=1250;
    }
    if (scratch[0] & 0x1) {
      tmp_dec+=625;
    } 
    tmp_dec = tmp_dec / 1000;
    temp = tmp_int * 10 +tmp_dec;
    last_temp = millis();
  }  
  Serial.print("Temperature : ");
  Serial.print(temp);
  Serial.println("°C");
}