#include <OneWire.h>
/* Read up to X number of DS18S20 1-wire thermometers and output the temperate in C onto the 
 serial port.  Output format is
 D=2E:0:4B:46:FF:FF:E:10:91:22.875
 Where "D=" is the start of record, 
 2E:0:4B:46:FF:FF:E:10 is the device's 48bit address
 91 is the CRC calculated and transmitted by the device
 22.875 is the temperature  measured by the device in C
 */

#define CONVERT     0x44
#define READSCRATCH 0xBE
#define SKIP_ROM    0xCC
#define MATCH_ROM   0x55



void setup(void) 
{
  Serial.begin(9600);
}


void loop(void) 
{
  byte i;
  byte s;
  byte present = 0;
  byte data[12];
  byte addr[8];
  char buff[15];
  float real_temp;
  float temp_count;
  float read_temp; 
  int sensors[]= { 13, 12, 11, 9, 8, 7, 4, 2 }; // pins that 1-wire sensors are on
  int num_sensors = 8; // set to the number of DS18S20P sensors attached

  while(1)
  {
    for (s=0; s< num_sensors; s++) { // We loop over sensors[] because we are in a 1-wire star topology
      OneWire  ds(sensors[s]); // set the sensor to read
      
      Serial.print("Reading pin "); //just a little debug output
      Serial.println(sensors[s]); // 
      if ( !ds.search(addr))   // Search for 1-wire device
      {
        ds.reset_search(); //stop the search 
      }

      if ( OneWire::crc8( addr, 7) != addr[7])   // Check CRC is valid
      {
        Serial.print("CRC is not valid!\n");
      }

      if ( addr[0] != 0x10) {                    // Make sure it is a DS18S20 device
        for ( i = 0; i < 9; i++) {               // If it isn't
          Serial.print(addr[i], HEX);            // print out the device address
          Serial.print(":");
        }
        Serial.println(" is not a DS18S20 family device.");
      }

      ds.reset();                               // Reset device 
      ds.select(addr);                          // Select device
      ds.write(CONVERT,1);                      // Issue Convert to the device (wake up, read temp)
      delay(1000);                             // It takes at least 750ms between each sensor to read temp
      present = ds.reset();                    // Reset device
      ds.select(addr);                         // Select device 
      ds.write(READSCRATCH,1);                 // Read the Temp from the DS scratchpad
      Serial.print("D=");
      for ( i = 0; i < 9; i++) {               // we need 9 bytes
        Serial.print(addr[i], HEX);            // print out the device address
        Serial.print(":");
      }

      for ( i = 0; i < 9; i++) {               // Grab the 9 bytes worth of data from the sensor 
        data[i] = ds.read();                   // that we found earlier 
        Serial.print(data[i], HEX);
        Serial.print(":");
      }


      if(OneWire::crc8( data, 8) == data[8])  // Check CRC is valid
      {
        // CRC is ok
        read_temp=((data[1]<<8) | data[0]) >> 1 ;            // Manipulate the temperature
        temp_count=float(data[7] - data[6])/(float)data[7];  // Convert to real temperature
        real_temp = ((float)read_temp-0.25)+temp_count;

        tempToAscii(real_temp,buff);              // Convert float to ascii
        Serial.println(buff);                     // Sent it out on serial  
      }
      else
      {  //CRC faild display -------
        Serial.println("CRC fail");
      }
    }    
  }

}
void tempToAscii(double temp, char *buff)
{
  int frac;
  frac=(unsigned int)(temp*1000)%1000;  //get three numbers to the right of the decimal point
  itoa((int)temp,buff,10);

  strcat(buff,".");
  itoa(frac,&buff[strlen(buff)],10); //put the frac after the decimal

}