DallasTemperature.cpp

// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.

// Version 3.7.2 modified on Dec 6, 2011 to support Arduino 1.0
// See Includes...
// Modified by Jordan Hochenbaum

// Modified by Tom de Boer @ 26-jun-2014 (Spark Core compatibility)

#include "DallasTemperature.h"

DallasTemperature::DallasTemperature(OneWire* _oneWire)
#if REQUIRESALARMS
    : _AlarmHandler(&defaultAlarmHandler)
#endif
{
    _wire = _oneWire;
    devices = 0;
    parasite = false;
    bitResolution = 9;
    waitForConversion = true;
    checkForConversion = true;
}

// initialise the bus
void DallasTemperature::begin(void)
{
    DeviceAddress deviceAddress;

    _wire->reset_search();
    devices = 0; // Reset the number of devices when we enumerate wire devices

    while (_wire->search(deviceAddress))
    {
        if (validAddress(deviceAddress))
        {
            if (!parasite && readPowerSupply(deviceAddress)) parasite = true;

            ScratchPad scratchPad;

            readScratchPad(deviceAddress, scratchPad);

            bitResolution = max(bitResolution, getResolution(deviceAddress));

            devices++;
        }
    }
}

// returns the number of devices found on the bus
uint8_t DallasTemperature::getDeviceCount(void)
{
    return devices;
}

// returns true if address is valid
bool DallasTemperature::validAddress(const uint8_t* deviceAddress)
{
    return (_wire->crc8((uint8_t*)deviceAddress, 7) == deviceAddress[7]);
}

// finds an address at a given index on the bus
// returns true if the device was found
bool DallasTemperature::getAddress(uint8_t* deviceAddress, uint8_t index)
{
    uint8_t depth = 0;

    _wire->reset_search();

    while (depth <= index && _wire->search(deviceAddress))
    {
        if (depth == index && validAddress(deviceAddress)) return true;
        depth++;
    }

    return false;
}

// attempt to determine if the device at the given address is connected to the bus
bool DallasTemperature::isConnected(const uint8_t* deviceAddress)
{
    ScratchPad scratchPad;
    return isConnected(deviceAddress, scratchPad);
}

// attempt to determine if the device at the given address is connected to the bus
// also allows for updating the read scratchpad
bool DallasTemperature::isConnected(const uint8_t* deviceAddress, uint8_t* scratchPad)
{
    readScratchPad(deviceAddress, scratchPad);
    return (_wire->crc8(scratchPad, 8) == scratchPad[SCRATCHPAD_CRC]);
}

// read device's scratch pad
void DallasTemperature::readScratchPad(const uint8_t* deviceAddress, uint8_t* scratchPad)
{
    // send the command
    _wire->reset();
    _wire->select(deviceAddress);
    _wire->write(READSCRATCH);

    // TODO => collect all comments &  use simple loop
    // byte 0: temperature LSB
    // byte 1: temperature MSB
    // byte 2: high alarm temp
    // byte 3: low alarm temp
    // byte 4: DS18S20: store for crc
    //         DS18B20 & DS1822: configuration register
    // byte 5: internal use & crc
    // byte 6: DS18S20: COUNT_REMAIN
    //         DS18B20 & DS1822: store for crc
    // byte 7: DS18S20: COUNT_PER_C
    //         DS18B20 & DS1822: store for crc
    // byte 8: SCRATCHPAD_CRC
    //
    // for(int i=0; i<9; i++)
    // {
    //   scratchPad[i] = _wire->read();
    // }


    // read the response

    // byte 0: temperature LSB
    scratchPad[TEMP_LSB] = _wire->read();

    // byte 1: temperature MSB
    scratchPad[TEMP_MSB] = _wire->read();

    // byte 2: high alarm temp
    scratchPad[HIGH_ALARM_TEMP] = _wire->read();

    // byte 3: low alarm temp
    scratchPad[LOW_ALARM_TEMP] = _wire->read();

    // byte 4:
    // DS18S20: store for crc
    // DS18B20 & DS1822: configuration register
    scratchPad[CONFIGURATION] = _wire->read();

    // byte 5:
    // internal use & crc
    scratchPad[INTERNAL_BYTE] = _wire->read();

    // byte 6:
    // DS18S20: COUNT_REMAIN
    // DS18B20 & DS1822: store for crc
    scratchPad[COUNT_REMAIN] = _wire->read();

    // byte 7:
    // DS18S20: COUNT_PER_C
    // DS18B20 & DS1822: store for crc
    scratchPad[COUNT_PER_C] = _wire->read();

    // byte 8:
    // SCTRACHPAD_CRC
    scratchPad[SCRATCHPAD_CRC] = _wire->read();

    _wire->reset();
}

// writes device's scratch pad
void DallasTemperature::writeScratchPad(const uint8_t* deviceAddress, const uint8_t* scratchPad)
{
    _wire->reset();
    _wire->select(deviceAddress);
    _wire->write(WRITESCRATCH);
    _wire->write(scratchPad[HIGH_ALARM_TEMP]); // high alarm temp
    _wire->write(scratchPad[LOW_ALARM_TEMP]); // low alarm temp
    // DS1820 and DS18S20 have no configuration register
    if (deviceAddress[0] != DS18S20MODEL) _wire->write(scratchPad[CONFIGURATION]); // configuration
    _wire->reset();
    _wire->select(deviceAddress); //<--this line was missing
    // save the newly written values to eeprom
    _wire->write(COPYSCRATCH, parasite);
    if (parasite) delay(10); // 10ms delay
    _wire->reset();
}

// reads the device's power requirements
bool DallasTemperature::readPowerSupply(const uint8_t* deviceAddress)
{
    bool ret = false;
    _wire->reset();
    _wire->select(deviceAddress);
    _wire->write(READPOWERSUPPLY);
    if (_wire->read_bit() == 0) ret = true;
    _wire->reset();
    return ret;
}


// set resolution of all devices to 9, 10, 11, or 12 bits
// if new resolution is out of range, it is constrained.
void DallasTemperature::setResolution(uint8_t newResolution)
{
    bitResolution = constrain(newResolution, 9, 12);
    DeviceAddress deviceAddress;
    for (int i=0; i<devices; i++)
    {
        getAddress(deviceAddress, i);
        setResolution(deviceAddress, bitResolution);
    }
}

// set resolution of a device to 9, 10, 11, or 12 bits
// if new resolution is out of range, 9 bits is used.
bool DallasTemperature::setResolution(const uint8_t* deviceAddress, uint8_t newResolution)
{
    ScratchPad scratchPad;
    if (isConnected(deviceAddress, scratchPad))
    {
        // DS1820 and DS18S20 have no resolution configuration register
        if (deviceAddress[0] != DS18S20MODEL)
        {
            switch (newResolution)
            {
            case 12:
                scratchPad[CONFIGURATION] = TEMP_12_BIT;
                break;
            case 11:
                scratchPad[CONFIGURATION] = TEMP_11_BIT;
                break;
            case 10:
                scratchPad[CONFIGURATION] = TEMP_10_BIT;
                break;
            case 9:
            default:
                scratchPad[CONFIGURATION] = TEMP_9_BIT;
                break;
            }
            writeScratchPad(deviceAddress, scratchPad);
        }
        return true;  // new value set
    }
    return false;
}

// returns the global resolution
uint8_t DallasTemperature::getResolution()
{
    return bitResolution;
}

// returns the current resolution of the device, 9-12
// returns 0 if device not found
uint8_t DallasTemperature::getResolution(const uint8_t* deviceAddress)
{
    // DS1820 and DS18S20 have no resolution configuration register
    if (deviceAddress[0] == DS18S20MODEL) return 12;

    ScratchPad scratchPad;
    if (isConnected(deviceAddress, scratchPad))
    {
        switch (scratchPad[CONFIGURATION])
        {
        case TEMP_12_BIT:
            return 12;

        case TEMP_11_BIT:
            return 11;

        case TEMP_10_BIT:
            return 10;

        case TEMP_9_BIT:
            return 9;
        }
    }
    return 0;
}


// sets the value of the waitForConversion flag
// TRUE : function requestTemperature() etc returns when conversion is ready
// FALSE: function requestTemperature() etc returns immediately (USE WITH CARE!!)
//        (1) programmer has to check if the needed delay has passed
//        (2) but the application can do meaningful things in that time
void DallasTemperature::setWaitForConversion(bool flag)
{
    waitForConversion = flag;
}

// gets the value of the waitForConversion flag
bool DallasTemperature::getWaitForConversion()
{
    return waitForConversion;
}


// sets the value of the checkForConversion flag
// TRUE : function requestTemperature() etc will 'listen' to an IC to determine whether a conversion is complete
// FALSE: function requestTemperature() etc will wait a set time (worst case scenario) for a conversion to complete
void DallasTemperature::setCheckForConversion(bool flag)
{
    checkForConversion = flag;
}

// gets the value of the waitForConversion flag
bool DallasTemperature::getCheckForConversion()
{
    return checkForConversion;
}

bool DallasTemperature::isConversionAvailable(const uint8_t* deviceAddress)
{
    // Check if the clock has been raised indicating the conversion is complete
    ScratchPad scratchPad;
    readScratchPad(deviceAddress, scratchPad);
    return scratchPad[0];
}


// sends command for all devices on the bus to perform a temperature conversion
void DallasTemperature::requestTemperatures()
{
    _wire->reset();
    _wire->skip();
    _wire->write(STARTCONVO, parasite);

    // ASYNC mode?
    if (!waitForConversion) return;
    blockTillConversionComplete(bitResolution, NULL);
}

// sends command for one device to perform a temperature by address
// returns FALSE if device is disconnected
// returns TRUE  otherwise
bool DallasTemperature::requestTemperaturesByAddress(const uint8_t* deviceAddress)
{
    _wire->reset();
    _wire->select(deviceAddress);
    _wire->write(STARTCONVO, parasite);

    // check device
    ScratchPad scratchPad;
    if (!isConnected(deviceAddress, scratchPad)) return false;

    // ASYNC mode?
    if (!waitForConversion) return true;
    blockTillConversionComplete(getResolution(deviceAddress), deviceAddress);

    return true;
}

// returns number of milliseconds to wait till conversion is complete (based on IC datasheet)
int16_t DallasTemperature::millisToWaitForConversion(uint8_t bitResolution)
{
    switch (bitResolution)
    {
    case 9:
        return 94;
    case 10:
        return 188;
    case 11:
        return 375;
    default:
        return 750;
    }
}

// Continue to check if the IC has responded with a temperature
void DallasTemperature::blockTillConversionComplete(uint8_t bitResolution, const uint8_t* deviceAddress)
{
    int delms = millisToWaitForConversion(bitResolution);
    if (deviceAddress != NULL && checkForConversion && !parasite)
    {
        unsigned long timend = millis() + delms;
        while(!isConversionAvailable(deviceAddress) && (millis() < timend));
    }
    else
    {
        delay(delms);
    }
}

// sends command for one device to perform a temp conversion by index
bool DallasTemperature::requestTemperaturesByIndex(uint8_t deviceIndex)
{
    DeviceAddress deviceAddress;
    getAddress(deviceAddress, deviceIndex);
    return requestTemperaturesByAddress(deviceAddress);
}

// Fetch temperature for device index
float DallasTemperature::getTempCByIndex(uint8_t deviceIndex)
{
    DeviceAddress deviceAddress;
    if (!getAddress(deviceAddress, deviceIndex))
        return DEVICE_DISCONNECTED_C;
    return getTempC((uint8_t*)deviceAddress);
}

// Fetch temperature for device index
float DallasTemperature::getTempFByIndex(uint8_t deviceIndex)
{
    DeviceAddress deviceAddress;
    if (!getAddress(deviceAddress, deviceIndex))
        return DEVICE_DISCONNECTED_F;
    return getTempF((uint8_t*)deviceAddress);
}

// reads scratchpad and returns fixed-point temperature, scaling factor 2^-7
int16_t DallasTemperature::calculateTemperature(const uint8_t* deviceAddress, uint8_t* scratchPad)
{
    int16_t fpTemperature =
        (((int16_t) scratchPad[TEMP_MSB]) << 11) |
        (((int16_t) scratchPad[TEMP_LSB]) << 3);

    /*
    DS1820 and DS18S20 have a 9-bit temperature register.

    Resolutions greater than 9-bit can be calculated using the data from
    the temperature, and COUNT REMAIN and COUNT PER °C registers in the
    scratchpad.  The resolution of the calculation depends on the model.

    While the COUNT PER °C register is hard-wired to 16 (10h) in a
    DS18S20, it changes with temperature in DS1820.

    After reading the scratchpad, the TEMP_READ value is obtained by
    truncating the 0.5°C bit (bit 0) from the temperature data. The
    extended resolution temperature can then be calculated using the
    following equation:

                                    COUNT_PER_C - COUNT_REMAIN
    TEMPERATURE = TEMP_READ - 0.25 + --------------------------
                                            COUNT_PER_C

    Hagai Shatz simplified this to integer arithmetic for a 12 bits
    value for a DS18S20, and James Cameron added legacy DS1820 support.

    See - http://myarduinotoy.blogspot.co.uk/2013/02/12bit-result-from-ds18s20.html
    */

    if (deviceAddress[0] == DS18S20MODEL)
        fpTemperature = ((fpTemperature & 0xfff0) << 3) - 16 +
            (
                ((scratchPad[COUNT_PER_C] - scratchPad[COUNT_REMAIN]) << 7) /
                  scratchPad[COUNT_PER_C]
            );

    return fpTemperature;
}


// returns temperature in 1/128 degrees C or DEVICE_DISCONNECTED_RAW if the
// device's scratch pad cannot be read successfully.
// the numeric value of DEVICE_DISCONNECTED_RAW is defined in
// DallasTemperature.h. It is a large negative number outside the
// operating range of the device
int16_t DallasTemperature::getTemp(const uint8_t* deviceAddress)
{
    ScratchPad scratchPad;
    if (isConnected(deviceAddress, scratchPad)) return calculateTemperature(deviceAddress, scratchPad);
    return DEVICE_DISCONNECTED_RAW;
}

// returns temperature in degrees C or DEVICE_DISCONNECTED_C if the
// device's scratch pad cannot be read successfully.
// the numeric value of DEVICE_DISCONNECTED_C is defined in
// DallasTemperature.h. It is a large negative number outside the
// operating range of the device
float DallasTemperature::getTempC(const uint8_t* deviceAddress)
{
    return rawToCelsius(getTemp(deviceAddress));
}

// returns temperature in degrees F or DEVICE_DISCONNECTED_F if the
// device's scratch pad cannot be read successfully.
// the numeric value of DEVICE_DISCONNECTED_F is defined in
// DallasTemperature.h. It is a large negative number outside the
// operating range of the device
float DallasTemperature::getTempF(const uint8_t* deviceAddress)
{
    return rawToFahrenheit(getTemp(deviceAddress));
}

// returns true if the bus requires parasite power
bool DallasTemperature::isParasitePowerMode(void)
{
    return parasite;
}

#if REQUIRESALARMS

/*

ALARMS:

TH and TL Register Format

BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
  S    2^6   2^5   2^4   2^3   2^2   2^1   2^0

Only bits 11 through 4 of the temperature register are used
in the TH and TL comparison since TH and TL are 8-bit
registers. If the measured temperature is lower than or equal
to TL or higher than or equal to TH, an alarm condition exists
and an alarm flag is set inside the DS18B20. This flag is
updated after every temperature measurement; therefore, if the
alarm condition goes away, the flag will be turned off after
the next temperature conversion.

*/

// sets the high alarm temperature for a device in degrees Celsius
// accepts a float, but the alarm resolution will ignore anything
// after a decimal point.  valid range is -55C - 125C
void DallasTemperature::setHighAlarmTemp(const uint8_t* deviceAddress, char celsius)
{
    // make sure the alarm temperature is within the device's range
    if (celsius > 125) celsius = 125;
    else if (celsius < -55) celsius = -55;

    ScratchPad scratchPad;
    if (isConnected(deviceAddress, scratchPad))
    {
        scratchPad[HIGH_ALARM_TEMP] = (uint8_t)celsius;
        writeScratchPad(deviceAddress, scratchPad);
    }
}

// sets the low alarm temperature for a device in degrees Celsius
// accepts a float, but the alarm resolution will ignore anything
// after a decimal point.  valid range is -55C - 125C
void DallasTemperature::setLowAlarmTemp(const uint8_t* deviceAddress, char celsius)
{
    // make sure the alarm temperature is within the device's range
    if (celsius > 125) celsius = 125;
    else if (celsius < -55) celsius = -55;

    ScratchPad scratchPad;
    if (isConnected(deviceAddress, scratchPad))
    {
        scratchPad[LOW_ALARM_TEMP] = (uint8_t)celsius;
        writeScratchPad(deviceAddress, scratchPad);
    }
}

// returns a char with the current high alarm temperature or
// DEVICE_DISCONNECTED for an address
char DallasTemperature::getHighAlarmTemp(const uint8_t* deviceAddress)
{
    ScratchPad scratchPad;
    if (isConnected(deviceAddress, scratchPad)) return (char)scratchPad[HIGH_ALARM_TEMP];
    return DEVICE_DISCONNECTED_C;
}

// returns a char with the current low alarm temperature or
// DEVICE_DISCONNECTED for an address
char DallasTemperature::getLowAlarmTemp(const uint8_t* deviceAddress)
{
    ScratchPad scratchPad;
    if (isConnected(deviceAddress, scratchPad)) return (char)scratchPad[LOW_ALARM_TEMP];
    return DEVICE_DISCONNECTED_C;
}

// resets internal variables used for the alarm search
void DallasTemperature::resetAlarmSearch()
{
    alarmSearchJunction = -1;
    alarmSearchExhausted = 0;
    for(uint8_t i = 0; i < 7; i++)
        alarmSearchAddress[i] = 0;
}

// This is a modified version of the OneWire::search method.
//
// Also added the OneWire search fix documented here:
// http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1238032295
//
// Perform an alarm search. If this function returns a '1' then it has
// enumerated the next device and you may retrieve the ROM from the
// OneWire::address variable. If there are no devices, no further
// devices, or something horrible happens in the middle of the
// enumeration then a 0 is returned.  If a new device is found then
// its address is copied to newAddr.  Use
// DallasTemperature::resetAlarmSearch() to start over.
bool DallasTemperature::alarmSearch(uint8_t* newAddr)
{
    uint8_t i;
    char lastJunction = -1;
    uint8_t done = 1;

    if (alarmSearchExhausted) return false;
    if (!_wire->reset()) return false;

    // send the alarm search command
    _wire->write(0xEC, 0);

    for(i = 0; i < 64; i++)
    {
        uint8_t a = _wire->read_bit( );
        uint8_t nota = _wire->read_bit( );
        uint8_t ibyte = i / 8;
        uint8_t ibit = 1 << (i & 7);

        // I don't think this should happen, this means nothing responded, but maybe if
        // something vanishes during the search it will come up.
        if (a && nota) return false;

        if (!a && !nota)
        {
            if (i == alarmSearchJunction)
            {
                // this is our time to decide differently, we went zero last time, go one.
                a = 1;
                alarmSearchJunction = lastJunction;
            }
            else if (i < alarmSearchJunction)
            {
                // take whatever we took last time, look in address
                if (alarmSearchAddress[ibyte] & ibit) a = 1;
                else
                {
                    // Only 0s count as pending junctions, we've already exhausted the 0 side of 1s
                    a = 0;
                    done = 0;
                    lastJunction = i;
                }
            }
            else
            {
                // we are blazing new tree, take the 0
                a = 0;
                alarmSearchJunction = i;
                done = 0;
            }
            // OneWire search fix
            // See: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1238032295
        }

        if (a) alarmSearchAddress[ibyte] |= ibit;
        else alarmSearchAddress[ibyte] &= ~ibit;

        _wire->write_bit(a);
    }

    if (done) alarmSearchExhausted = 1;
    for (i = 0; i < 8; i++) newAddr[i] = alarmSearchAddress[i];
    return true;
}

// returns true if device address might have an alarm condition
// (only an alarm search can verify this)
bool DallasTemperature::hasAlarm(const uint8_t* deviceAddress)
{
    ScratchPad scratchPad;
    if (isConnected(deviceAddress, scratchPad))
    {
        char temp = calculateTemperature(deviceAddress, scratchPad) >> 7;

        // check low alarm
        if (temp <= (char)scratchPad[LOW_ALARM_TEMP]) return true;

        // check high alarm
        if (temp >= (char)scratchPad[HIGH_ALARM_TEMP]) return true;
    }

    // no alarm
    return false;
}

// returns true if any device is reporting an alarm condition on the bus
bool DallasTemperature::hasAlarm(void)
{
    DeviceAddress deviceAddress;
    resetAlarmSearch();
    return alarmSearch(deviceAddress);
}

// runs the alarm handler for all devices returned by alarmSearch()
void DallasTemperature::processAlarms(void)
{
    resetAlarmSearch();
    DeviceAddress alarmAddr;

    while (alarmSearch(alarmAddr))
    {
        if (validAddress(alarmAddr))
            _AlarmHandler(alarmAddr);
    }
}

// sets the alarm handler
void DallasTemperature::setAlarmHandler(AlarmHandler *handler)
{
    _AlarmHandler = handler;
}

// The default alarm handler
void DallasTemperature::defaultAlarmHandler(const uint8_t* deviceAddress)
{
}

#endif

// Convert float Celsius to Fahrenheit
float DallasTemperature::toFahrenheit(float celsius)
{
    return (celsius * 1.8) + 32;
}

// Convert float Fahrenheit to Celsius
float DallasTemperature::toCelsius(float fahrenheit)
{
    return (fahrenheit - 32) * 0.555555556;
}

// convert from raw to Celsius
float DallasTemperature::rawToCelsius(int16_t raw)
{
    if (raw <= DEVICE_DISCONNECTED_RAW)
        return DEVICE_DISCONNECTED_C;
    // C = RAW/128
    return (float)raw * 0.0078125;
}

// convert from raw to Fahrenheit
float DallasTemperature::rawToFahrenheit(int16_t raw)
{
    if (raw <= DEVICE_DISCONNECTED_RAW)
        return DEVICE_DISCONNECTED_F;
    // C = RAW/128
    // F = (C*1.8)+32 = (RAW/128*1.8)+32 = (RAW*0.0140625)+32
    return ((float)raw * 0.0140625) + 32;
}

#if REQUIRESNEW

// MnetCS - Allocates memory for DallasTemperature. Allows us to instance a new object
void* DallasTemperature::operator new(unsigned int size) // Implicit NSS obj size
{
    void * p; // void pointer
    p = malloc(size); // Allocate memory
    memset((DallasTemperature*)p,0,size); // Initialise memory

    //!!! CANT EXPLICITLY CALL CONSTRUCTOR - workaround by using an init() methodR - workaround by using an init() method
    return (DallasTemperature*) p; // Cast blank region to NSS pointer
}

// MnetCS 2009 -  Free the memory used by this instance
void DallasTemperature::operator delete(void* p)
{
    DallasTemperature* pNss =  (DallasTemperature*) p; // Cast to NSS pointer
    pNss->~DallasTemperature(); // Destruct the object

    free(p); // Free the memory
}

#endif

DallasTemperature.h

#ifndef DallasTemperature_h
#define DallasTemperature_h

#define DALLASTEMPLIBVERSION "3.7.2"

// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.

// set to true to include code for new and delete operators
#ifndef REQUIRESNEW
#define REQUIRESNEW false
#endif

// set to true to include code implementing alarm search functions
#ifndef REQUIRESALARMS
#define REQUIRESALARMS true
#endif

#include <inttypes.h>

#if defined(ARDUINO) && ARDUINO >= 100
    #include <OneWire.h>
#elif defined(SPARK) or defined(STM32F10X_MD)
    #include "application.h"
    #include "OneWire/OneWire.h"
#endif


// Model IDs
#define DS18S20MODEL 0x10  // also DS1820
#define DS18B20MODEL 0x28
#define DS1822MODEL  0x22
#define DS1825MODEL  0x3B

// OneWire commands
#define STARTCONVO      0x44  // Tells device to take a temperature reading and put it on the scratchpad
#define COPYSCRATCH     0x48  // Copy EEPROM
#define READSCRATCH     0xBE  // Read EEPROM
#define WRITESCRATCH    0x4E  // Write to EEPROM
#define RECALLSCRATCH   0xB8  // Reload from last known
#define READPOWERSUPPLY 0xB4  // Determine if device needs parasite power
#define ALARMSEARCH     0xEC  // Query bus for devices with an alarm condition

// Scratchpad locations
#define TEMP_LSB        0
#define TEMP_MSB        1
#define HIGH_ALARM_TEMP 2
#define LOW_ALARM_TEMP  3
#define CONFIGURATION   4
#define INTERNAL_BYTE   5
#define COUNT_REMAIN    6
#define COUNT_PER_C     7
#define SCRATCHPAD_CRC  8

// Device resolution
#define TEMP_9_BIT  0x1F //  9 bit
#define TEMP_10_BIT 0x3F // 10 bit
#define TEMP_11_BIT 0x5F // 11 bit
#define TEMP_12_BIT 0x7F // 12 bit

// Error Codes
#define DEVICE_DISCONNECTED_C -127
#define DEVICE_DISCONNECTED_F -196.6
#define DEVICE_DISCONNECTED_RAW -2032

typedef uint8_t DeviceAddress[8];

class DallasTemperature
{
  public:

  DallasTemperature(OneWire*);

  // initialise bus
  void begin(void);

  // returns the number of devices found on the bus
  uint8_t getDeviceCount(void);
  
  // returns true if address is valid
  bool validAddress(const uint8_t*);

  // finds an address at a given index on the bus 
  bool getAddress(uint8_t*, uint8_t);
  
  // attempt to determine if the device at the given address is connected to the bus
  bool isConnected(const uint8_t*);

  // attempt to determine if the device at the given address is connected to the bus
  // also allows for updating the read scratchpad
  bool isConnected(const uint8_t*, uint8_t*);

  // read device's scratchpad
  void readScratchPad(const uint8_t*, uint8_t*);

  // write device's scratchpad
  void writeScratchPad(const uint8_t*, const uint8_t*);

  // read device's power requirements
  bool readPowerSupply(const uint8_t*);

  // get global resolution
  uint8_t getResolution();
  
  // set global resolution to 9, 10, 11, or 12 bits
  void setResolution(uint8_t);

  // returns the device resolution: 9, 10, 11, or 12 bits
  uint8_t getResolution(const uint8_t*);

  // set resolution of a device to 9, 10, 11, or 12 bits
  bool setResolution(const uint8_t*, uint8_t);
  
  // sets/gets the waitForConversion flag
  void setWaitForConversion(bool);
  bool getWaitForConversion(void);
  
  // sets/gets the checkForConversion flag
  void setCheckForConversion(bool);
  bool getCheckForConversion(void);
  
  // sends command for all devices on the bus to perform a temperature conversion 
  void requestTemperatures(void);
   
  // sends command for one device to perform a temperature conversion by address
  bool requestTemperaturesByAddress(const uint8_t*);

  // sends command for one device to perform a temperature conversion by index
  bool requestTemperaturesByIndex(uint8_t);

  // returns temperature raw value (12 bit integer of 1/16 degrees C)
  int16_t getTemp(const uint8_t*);

  // returns temperature in degrees C
  float getTempC(const uint8_t*);

  // returns temperature in degrees F
  float getTempF(const uint8_t*);

  // Get temperature for device index (slow)
  float getTempCByIndex(uint8_t);
  
  // Get temperature for device index (slow)
  float getTempFByIndex(uint8_t);
  
  // returns true if the bus requires parasite power
  bool isParasitePowerMode(void);
  
  bool isConversionAvailable(const uint8_t*);

  #if REQUIRESALARMS
  
  typedef void AlarmHandler(const uint8_t*);

  // sets the high alarm temperature for a device
  // accepts a char.  valid range is -55C - 125C
  void setHighAlarmTemp(const uint8_t*, char);

  // sets the low alarm temperature for a device
  // accepts a char.  valid range is -55C - 125C
  void setLowAlarmTemp(const uint8_t*, char);

  // returns a signed char with the current high alarm temperature for a device
  // in the range -55C - 125C
  char getHighAlarmTemp(const uint8_t*);

  // returns a signed char with the current low alarm temperature for a device
  // in the range -55C - 125C
  char getLowAlarmTemp(const uint8_t*);
  
  // resets internal variables used for the alarm search
  void resetAlarmSearch(void);

  // search the wire for devices with active alarms
  bool alarmSearch(uint8_t*);

  // returns true if ia specific device has an alarm
  bool hasAlarm(const uint8_t*);

  // returns true if any device is reporting an alarm on the bus
  bool hasAlarm(void);

  // runs the alarm handler for all devices returned by alarmSearch()
  void processAlarms(void);
  
  // sets the alarm handler
  void setAlarmHandler(const AlarmHandler *);
  
  // The default alarm handler
  static void defaultAlarmHandler(const uint8_t*);

  #endif

  // convert from Celsius to Fahrenheit
  static float toFahrenheit(float);

  // convert from Fahrenheit to Celsius
  static float toCelsius(float);

  // convert from raw to Celsius
  static float rawToCelsius(int16_t);

  // convert from raw to Fahrenheit
  static float rawToFahrenheit(int16_t);

  #if REQUIRESNEW

  // initialize memory area
  void* operator new (unsigned int);

  // delete memory reference
  void operator delete(void*);
  
  #endif

  private:
  typedef uint8_t ScratchPad[9];
  
  // parasite power on or off
  bool parasite;

  // used to determine the delay amount needed to allow for the
  // temperature conversion to take place
  uint8_t bitResolution;
  
  // used to requestTemperature with or without delay
  bool waitForConversion;
  
  // used to requestTemperature to dynamically check if a conversion is complete
  bool checkForConversion;
  
  // count of devices on the bus
  uint8_t devices;
  
  // Take a pointer to one wire instance
  OneWire* _wire;

  // reads scratchpad and returns the raw temperature
  int16_t calculateTemperature(const uint8_t*, uint8_t*);
  
  int16_t millisToWaitForConversion(uint8_t);

  void  blockTillConversionComplete(uint8_t, const uint8_t*);
  
  #if REQUIRESALARMS

  // required for alarmSearch 
  uint8_t alarmSearchAddress[8];
  char alarmSearchJunction;
  uint8_t alarmSearchExhausted;

  // the alarm handler function pointer
  AlarmHandler *_AlarmHandler;

  #endif
  
};
#endif

DS18B20Example.cpp

#pragma SPARK_NO_PREPROCESSOR

// DS18B20 Thermometer Stuff
#include "DallasTemperature.h"
#include "OneWire/OneWire.h"
#define ONE_WIRE_BUS D1
#define TEMPERATURE_PRECISION 9
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);
DeviceAddress inWaterThermometer = { 0x28, 0x2E, 0x54, 0x0A, 0x06, 0x0, 0x0, 0xFB };
DeviceAddress outWaterThermometer = { 0x28, 0xF7, 0xF0, 0x08, 0x06, 0x0, 0x0, 0x82 };
double spaInTempC = -1;
double spaOutTempC = -1;
void update18B20Temp(DeviceAddress deviceAddress, double &tempC);

// Misc Stuff
//char publishString[40];
unsigned long lastUpdate = 0;
unsigned long updateDelay = 1000;

void setup()
{
    // DS18B20
    sensors.begin();
    sensors.setResolution(inWaterThermometer, TEMPERATURE_PRECISION);
    sensors.setResolution(outWaterThermometer, TEMPERATURE_PRECISION);
    Spark.variable("spaITemp", &spaInTempC, DOUBLE);
    Spark.variable("spaOTemp", &spaOutTempC, DOUBLE);
    
    Serial.begin(9600);   // open serial over USB
    // On Windows it will be necessary to implement the following line:
    // Make sure your Serial Terminal app is closed before powering your Core
    // Now open your Serial Terminal, and hit any key to continue!
    while(!Serial.available()) SPARK_WLAN_Loop();
}

void loop()
{
    unsigned long now = millis();
    if((now - lastUpdate) > updateDelay)
    {
        lastUpdate = now;
        
        // To let the user know that an update is taking place the RGB LED is set to WHITE during the update
        RGB.control(true);
        RGB.color(125, 255, 125); 
        
        // DS18B20
        RGB.color(0, 200, 125); 
        sensors.requestTemperatures();
        update18B20Temp(inWaterThermometer, spaInTempC);
        update18B20Temp(outWaterThermometer, spaOutTempC);
        
        Serial.print("In Temp:");
        Serial.print(spaInTempC);
        Serial.print("C - Out Temp: ");
        Serial.print(spaOutTempC);
        Serial.println("C");
        /*
        // Check if there is need for an event
        if((!atTempAnnounced) && (spaInTempC > spaTargetTemp) && (spaTargetTemp != 0.0))
        {
            Spark.publish("spa", "TargetTempAchieved");
            atTempAnnounced = true;
        }
        */
        // Release control of the RGB LED
        RGB.control(false);
    }
}

void update18B20Temp(DeviceAddress deviceAddress, double &tempC)
{
  tempC = sensors.getTempC(deviceAddress);
}