#include <OneWire.h>
#include <Wire.h>

#define DISPLAY_ADDRESS1 0x71 //This is the default address of the OpenSegment with both solder jumpers open

// DS18S20 Temperature chip i/o
OneWire ds(10);  // on pin 10

void setup(void) {
  Wire.begin(); //Join the bus as master

  // initialize inputs/outputs
  // start serial port
  lookUpSensors();

  //Send the reset command to the display - this forces the cursor to return to the beginning of the display
  Wire.beginTransmission(DISPLAY_ADDRESS1);
  Wire.write('v');
  Wire.endTransmission();
}

void lookUpSensors()
{
  byte address[8];
  int i=0;
  byte ok = 0, tmp = 0;

  while (ds.search(address)) {
    tmp = 0;
    //0x10 = DS18S20
    if (address[0] == 0x10) {
      tmp = 1;
    }
    else {
      //0x28 = DS18B20
      if (address[0] == 0x28) {
        tmp = 1;
      }
    }
    //display the address, if tmp is ok
    if (tmp == 1) {
      if (OneWire::crc8(address, 7) != address[7]) {
        // but it doesn't have a valid CRC!
      }
      else {
        ok = 1;
      }
    }//end if tmp
  }//end while
}

int HighByte, LowByte, TReading, SignBit, Tc_100, Whole, Fract;

void loop(void) {
  byte i;
  byte present = 0;
  byte data[12];
  byte addr[8];

  byte dscount = 0;
  while (ds.search(addr)) {

    ds.reset();
    ds.select(addr);
    ds.write(0x44,1);         // start conversion, with parasite power on at the end

    delay(1000);     // maybe 750ms is enough, maybe not
    // we might do a ds.depower() here, but the reset will take care of it.

    present = ds.reset();
    ds.select(addr);    
    ds.write(0xBE);         // Read Scratchpad

    for ( i = 0; i < 9; i++) {           // we need 9 bytes
      data[i] = ds.read();
    }

    LowByte = data[0];
    HighByte = data[1];
    TReading = (HighByte << 8) + LowByte;
    SignBit = TReading & 0x8000;  // test most sig bit
    if (SignBit) {
      // negative
      TReading = (TReading ^ 0xffff) + 1; // 2's comp
    }
    Tc_100 = (6 * TReading) + TReading / 4;    // multiply by (100 * 0.0625) or 6.25

    Whole = Tc_100 / 100;  // separate off the whole and fractional portions
    Fract = Tc_100 % 100;

    // Output the value to the Display
    // First write delimiter and Sign for first or second DS.
    Wire.beginTransmission(DISPLAY_ADDRESS1);
    Wire.write(0x77);
    if (dscount ==0) {
      Wire.write(0x22); 
    } 
    else {
      Wire.write(0x02); 
    }
    Wire.endTransmission();

    // write Value to Display
    Wire.beginTransmission(DISPLAY_ADDRESS1);
    byte value = Whole / 10;
    Wire.write(value);
    value = Whole % 10;
    Wire.write(value);
    value = Fract / 10;
    Wire.write(value);
    value = Fract % 10;
    Wire.write(value);
    Wire.endTransmission();

    dscount++;
  }
}