spark core ds18b20 example

#ifndef OneWire_h
#define OneWire_h

#include <inttypes.h>
// you can exclude onewire_search by defining that to 0
#ifndef ONEWIRE_SEARCH
#define ONEWIRE_SEARCH 1
#endif

// You can exclude CRC checks altogether by defining this to 0
#ifndef ONEWIRE_CRC
#define ONEWIRE_CRC 1
#endif



// You can allow 16-bit CRC checks by defining this to 1
// (Note that ONEWIRE_CRC must also be 1.)
#ifndef ONEWIRE_CRC16
#define ONEWIRE_CRC16 1
#endif

#define FALSE 0
#define TRUE  1

class OneWire
{
  private:

    uint16_t _pin;
    void DIRECT_WRITE_LOW(void);
    void DIRECT_MODE_OUTPUT(void);
    void DIRECT_WRITE_HIGH(void);
    void DIRECT_MODE_INPUT(void);
    uint8_t DIRECT_READ(void);
#if ONEWIRE_SEARCH
    // global search state
    unsigned char ROM_NO[8];
    uint8_t LastDiscrepancy;
    uint8_t LastFamilyDiscrepancy;
    uint8_t LastDeviceFlag;
#endif

  public:
    OneWire( uint16_t pin);

    // Perform a 1-Wire reset cycle. Returns 1 if a device responds
    // with a presence pulse.  Returns 0 if there is no device or the
    // bus is shorted or otherwise held low for more than 250uS
    uint8_t reset(void);

    // Issue a 1-Wire rom select command, you do the reset first.
    void select(const uint8_t rom[8]);

    // Issue a 1-Wire rom skip command, to address all on bus.
    void skip(void);

    // Write a byte. If 'power' is one then the wire is held high at
    // the end for parasitically powered devices. You are responsible
    // for eventually depowering it by calling depower() or doing
    // another read or write.
    void write(uint8_t v, uint8_t power = 0);

    void write_bytes(const uint8_t *buf, uint16_t count, bool power = 0);

    // Read a byte.
    uint8_t read(void);

    void read_bytes(uint8_t *buf, uint16_t count);

    // Write a bit. The bus is always left powered at the end, see
    // note in write() about that.
    void write_bit(uint8_t v);

    // Read a bit.
    uint8_t read_bit(void);

    // Stop forcing power onto the bus. You only need to do this if
    // you used the 'power' flag to write() or used a write_bit() call
    // and aren't about to do another read or write. You would rather
    // not leave this powered if you don't have to, just in case
    // someone shorts your bus.
    void depower(void);

#if ONEWIRE_SEARCH
    // Clear the search state so that if will start from the beginning again.
    void reset_search();

    // Setup the search to find the device type 'family_code' on the next call
    // to search(*newAddr) if it is present.
    void target_search(uint8_t family_code);

    // Look for the next device. Returns 1 if a new address has been
    // returned. A zero might mean that the bus is shorted, there are
    // no devices, or you have already retrieved all of them.  It
    // might be a good idea to check the CRC to make sure you didn't
    // get garbage.  The order is deterministic. You will always get
    // the same devices in the same order.
    uint8_t search(uint8_t *newAddr);
#endif

#if ONEWIRE_CRC
    // Compute a Dallas Semiconductor 8 bit CRC, these are used in the
    // ROM and scratchpad registers.
    static uint8_t crc8(uint8_t *addr, uint8_t len);

#if ONEWIRE_CRC16
    // Compute the 1-Wire CRC16 and compare it against the received CRC.
    // Example usage (reading a DS2408):
    //    // Put everything in a buffer so we can compute the CRC easily.
    //    uint8_t buf[13];
    //    buf[0] = 0xF0;    // Read PIO Registers
    //    buf[1] = 0x88;    // LSB address
    //    buf[2] = 0x00;    // MSB address
    //    WriteBytes(net, buf, 3);    // Write 3 cmd bytes
    //    ReadBytes(net, buf+3, 10);  // Read 6 data bytes, 2 0xFF, 2 CRC16
    //    if (!CheckCRC16(buf, 11, &buf[11])) {
    //        // Handle error.
    //    }
    //
    // @param input - Array of bytes to checksum.
    // @param len - How many bytes to use.
    // @param inverted_crc - The two CRC16 bytes in the received data.
    //                       This should just point into the received data,
    //                       *not* at a 16-bit integer.
    // @param crc - The crc starting value (optional)
    // @return True, iff the CRC matches.
    static bool check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc = 0);

    // Compute a Dallas Semiconductor 16 bit CRC.  This is required to check
    // the integrity of data received from many 1-Wire devices.  Note that the
    // CRC computed here is *not* what you'll get from the 1-Wire network,
    // for two reasons:
    //   1) The CRC is transmitted bitwise inverted.
    //   2) Depending on the endian-ness of your processor, the binary
    //      representation of the two-byte return value may have a different
    //      byte order than the two bytes you get from 1-Wire.
    // @param input - Array of bytes to checksum.
    // @param len - How many bytes to use.
    // @param crc - The crc starting value (optional)
    // @return The CRC16, as defined by Dallas Semiconductor.
    static uint16_t crc16(const uint8_t* input, uint16_t len, uint16_t crc = 0);
#endif
#endif
};

#endif
OneWire::OneWire(uint16_t pin)
{
    pinMode(pin, INPUT);
     _pin = pin;

}

void OneWire::DIRECT_WRITE_LOW(void)
{
PIN_MAP[_pin].gpio_peripheral->BRR = PIN_MAP[_pin].gpio_pin;
}
void OneWire::DIRECT_MODE_OUTPUT(void)
{
GPIO_TypeDef *gpio_port = PIN_MAP[_pin].gpio_peripheral;
    uint16_t gpio_pin = PIN_MAP[_pin].gpio_pin;

        GPIO_InitTypeDef GPIO_InitStructure;

        if (gpio_port == GPIOA )
        {
                RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
        }
        else if (gpio_port == GPIOB )
        {
                RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
        }

    GPIO_InitStructure.GPIO_Pin = gpio_pin;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    PIN_MAP[_pin].pin_mode = OUTPUT;
    GPIO_Init(gpio_port, &GPIO_InitStructure);
}
void OneWire::DIRECT_WRITE_HIGH(void)
{
PIN_MAP[_pin].gpio_peripheral->BSRR = PIN_MAP[_pin].gpio_pin;
}
void OneWire::DIRECT_MODE_INPUT(void)
{
    GPIO_TypeDef *gpio_port = PIN_MAP[_pin].gpio_peripheral;
    uint16_t gpio_pin = PIN_MAP[_pin].gpio_pin;

        GPIO_InitTypeDef GPIO_InitStructure;

        if (gpio_port == GPIOA )
        {
                RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
        }
        else if (gpio_port == GPIOB )
        {
                RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
        }

    GPIO_InitStructure.GPIO_Pin = gpio_pin;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    PIN_MAP[_pin].pin_mode = INPUT;
GPIO_Init(gpio_port, &GPIO_InitStructure);
}
uint8_t OneWire::DIRECT_READ(void)
{
return GPIO_ReadInputDataBit(PIN_MAP[_pin].gpio_peripheral, PIN_MAP[_pin].gpio_pin);
}
// Perform the onewire reset function.  We will wait up to 250uS for
// the bus to come high, if it doesn't then it is broken or shorted
// and we return a 0;
//
// Returns 1 if a device asserted a presence pulse, 0 otherwise.
//

uint8_t OneWire::reset(void)
{
    uint8_t r;
    uint8_t retries = 125;

    noInterrupts();
    DIRECT_MODE_INPUT();
    interrupts();
    // wait until the wire is high... just in case
    do {
        if (--retries == 0) return 0;
        delayMicroseconds(2);
    } while ( !DIRECT_READ());

    noInterrupts();
    DIRECT_WRITE_LOW();
    DIRECT_MODE_OUTPUT();   // drive output low
    interrupts();
    delayMicroseconds(480);
    noInterrupts();
    DIRECT_MODE_INPUT();    // allow it to float
    delayMicroseconds(70);
    r = !DIRECT_READ();
    interrupts();
    delayMicroseconds(410);
    return r;
}
void OneWire::write_bit(uint8_t v)
{


    if (v & 1) {
        noInterrupts();
        DIRECT_WRITE_LOW();
        DIRECT_MODE_OUTPUT();   // drive output low
        delayMicroseconds(10);
        DIRECT_WRITE_HIGH();    // drive output high
        interrupts();
        delayMicroseconds(55);
    } else {
        noInterrupts();
        DIRECT_WRITE_LOW();
        DIRECT_MODE_OUTPUT();   // drive output low
        delayMicroseconds(65);
        DIRECT_WRITE_HIGH();    // drive output high
        interrupts();
        delayMicroseconds(5);
    }
}

//
// Read a bit. Port and bit is used to cut lookup time and provide
// more certain timing.
//
uint8_t OneWire::read_bit(void)
{

    uint8_t r;

    noInterrupts();
    DIRECT_MODE_OUTPUT();
    DIRECT_WRITE_LOW();
    delayMicroseconds(3);
    DIRECT_MODE_INPUT();    // let pin float, pull up will raise
    delayMicroseconds(10);
    r = DIRECT_READ();
    interrupts();
    delayMicroseconds(53);
    return r;
}

//
// Write a byte. The writing code uses the active drivers to raise the
// pin high, if you need power after the write (e.g. DS18S20 in
// parasite power mode) then set 'power' to 1, otherwise the pin will
// go tri-state at the end of the write to avoid heating in a short or
// other mishap.
//
void OneWire::write(uint8_t v, uint8_t power /* = 0 */) {
    uint8_t bitMask;

    for (bitMask = 0x01; bitMask; bitMask <<= 1) {
    OneWire::write_bit( (bitMask & v)?1:0);
    }
    if ( !power) {
    noInterrupts();
    DIRECT_MODE_INPUT();
    DIRECT_WRITE_LOW();
    interrupts();
    }
}

void OneWire::write_bytes(const uint8_t *buf, uint16_t count, bool power /* = 0 */) {
  for (uint16_t i = 0 ; i < count ; i++)
    write(buf[i]);
  if (!power) {
    noInterrupts();
    DIRECT_MODE_INPUT();
    DIRECT_WRITE_LOW();
    interrupts();
  }
}

//
// Read a byte
//
uint8_t OneWire::read() {
    uint8_t bitMask;
    uint8_t r = 0;

    for (bitMask = 0x01; bitMask; bitMask <<= 1) {
    if ( OneWire::read_bit()) r |= bitMask;
    }
    return r;
}

void OneWire::read_bytes(uint8_t *buf, uint16_t count) {
  for (uint16_t i = 0 ; i < count ; i++)
    buf[i] = read();
}

//
// Do a ROM select
//
void OneWire::select(const uint8_t rom[8])
{
    uint8_t i;

    write(0x55);           // Choose ROM

    for (i = 0; i < 8; i++) write(rom[i]);
}

//
// Do a ROM skip
//
void OneWire::skip()
{
    write(0xCC);           // Skip ROM
}

void OneWire::depower()
{
    noInterrupts();
    DIRECT_MODE_INPUT();
    interrupts();
}

#if ONEWIRE_SEARCH

//
// You need to use this function to start a search again from the beginning.
// You do not need to do it for the first search, though you could.
//
void OneWire::reset_search()
{
  // reset the search state
  LastDiscrepancy = 0;
  LastDeviceFlag = FALSE;
  LastFamilyDiscrepancy = 0;
  for(int i = 7; ; i--) {
    ROM_NO[i] = 0;
    if ( i == 0) break;
  }
}

// Setup the search to find the device type 'family_code' on the next call
// to search(*newAddr) if it is present.
//
void OneWire::target_search(uint8_t family_code)
{
   // set the search state to find SearchFamily type devices
   ROM_NO[0] = family_code;
   for (uint8_t i = 1; i < 8; i++)
      ROM_NO[i] = 0;
   LastDiscrepancy = 64;
   LastFamilyDiscrepancy = 0;
   LastDeviceFlag = FALSE;
}

//
// Perform a 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 OneWire::reset_search() to
// start over.
//
// --- Replaced by the one from the Dallas Semiconductor web site ---
//--------------------------------------------------------------------------
// Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing
// search state.
// Return TRUE  : device found, ROM number in ROM_NO buffer
//        FALSE : device not found, end of search
//
uint8_t OneWire::search(uint8_t *newAddr)
{
   uint8_t id_bit_number;
   uint8_t last_zero, rom_byte_number, search_result;
   uint8_t id_bit, cmp_id_bit;

   unsigned char rom_byte_mask, search_direction;

   // initialize for search
   id_bit_number = 1;
   last_zero = 0;
   rom_byte_number = 0;
   rom_byte_mask = 1;
   search_result = 0;

   // if the last call was not the last one
   if (!LastDeviceFlag)
   {
      // 1-Wire reset
      if (!reset())
      {
         // reset the search
         LastDiscrepancy = 0;
         LastDeviceFlag = FALSE;
         LastFamilyDiscrepancy = 0;
         return FALSE;
      }

      // issue the search command
      write(0xF0);

      // loop to do the search
      do
      {
         // read a bit and its complement
         id_bit = read_bit();
         cmp_id_bit = read_bit();

         // check for no devices on 1-wire
         if ((id_bit == 1) && (cmp_id_bit == 1))
            break;
         else
         {
            // all devices coupled have 0 or 1
            if (id_bit != cmp_id_bit)
               search_direction = id_bit;  // bit write value for search
            else
            {
               // if this discrepancy if before the Last Discrepancy
               // on a previous next then pick the same as last time
               if (id_bit_number < LastDiscrepancy)
                  search_direction = ((ROM_NO[rom_byte_number] & rom_byte_mask) > 0);
               else
                  // if equal to last pick 1, if not then pick 0
                  search_direction = (id_bit_number == LastDiscrepancy);

               // if 0 was picked then record its position in LastZero
               if (search_direction == 0)
               {
                  last_zero = id_bit_number;

                  // check for Last discrepancy in family
                  if (last_zero < 9)
                     LastFamilyDiscrepancy = last_zero;
               }
            }

            // set or clear the bit in the ROM byte rom_byte_number
            // with mask rom_byte_mask
            if (search_direction == 1)
              ROM_NO[rom_byte_number] |= rom_byte_mask;
            else
              ROM_NO[rom_byte_number] &= ~rom_byte_mask;

            // serial number search direction write bit
            write_bit(search_direction);

            // increment the byte counter id_bit_number
            // and shift the mask rom_byte_mask
            id_bit_number++;
            rom_byte_mask <<= 1;

            // if the mask is 0 then go to new SerialNum byte rom_byte_number and reset mask
            if (rom_byte_mask == 0)
            {
                rom_byte_number++;
                rom_byte_mask = 1;
            }
         }
      }
      while(rom_byte_number < 8);  // loop until through all ROM bytes 0-7

      // if the search was successful then
      if (!(id_bit_number < 65))
      {
         // search successful so set LastDiscrepancy,LastDeviceFlag,search_result
         LastDiscrepancy = last_zero;

         // check for last device
         if (LastDiscrepancy == 0)
            LastDeviceFlag = TRUE;

         search_result = TRUE;
      }
   }

   // if no device found then reset counters so next 'search' will be like a first
   if (!search_result || !ROM_NO[0])
   {
      LastDiscrepancy = 0;
      LastDeviceFlag = FALSE;
      LastFamilyDiscrepancy = 0;
      search_result = FALSE;
   }
   for (int i = 0; i < 8; i++) newAddr[i] = ROM_NO[i];
   return search_result;
  }

#endif

#if ONEWIRE_CRC
// The 1-Wire CRC scheme is described in Maxim Application Note 27:
// "Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products"
//


//
// Compute a Dallas Semiconductor 8 bit CRC directly.
// this is much slower, but much smaller, than the lookup table.
//
uint8_t OneWire::crc8( uint8_t *addr, uint8_t len)
{
    uint8_t crc = 0;

    while (len--) {
        uint8_t inbyte = *addr++;
        for (uint8_t i = 8; i; i--) {
            uint8_t mix = (crc ^ inbyte) & 0x01;
            crc >>= 1;
            if (mix) crc ^= 0x8C;
            inbyte >>= 1;
        }
    }
    return crc;
}
#endif

#if ONEWIRE_CRC16
bool OneWire::check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc)
{
    crc = ~crc16(input, len, crc);
    return (crc & 0xFF) == inverted_crc[0] && (crc >> 8) == inverted_crc[1];
}

uint16_t OneWire::crc16(const uint8_t* input, uint16_t len, uint16_t crc)
{
    static const uint8_t oddparity[16] =
        { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 };

    for (uint16_t i = 0 ; i < len ; i++) {
      // Even though we're just copying a byte from the input,
      // we'll be doing 16-bit computation with it.
      uint16_t cdata = input[i];
      cdata = (cdata ^ crc) & 0xff;
      crc >>= 8;

      if (oddparity[cdata & 0x0F] ^ oddparity[cdata >> 4])
          crc ^= 0xC001;

      cdata <<= 6;
      crc ^= cdata;
      cdata <<= 1;
      crc ^= cdata;
    }
    return crc;
}
#endif




OneWire one = OneWire(D3);
uint8_t rom[8];
uint8_t resp[9];
void setup() {
Serial1.begin(9600);
one.reset();
one.write(0x33);
one.read_bytes(rom,8);
Serial1.println("rom is:");
for(int i=0;i<8;i++)
{
   Serial1.println(rom[i],HEX);

}
}

void loop() {


one.reset();
one.write(0x55);
one.write_bytes(rom,8);
one.write(0x44);
delay(10);
one.reset();
one.write(0x55);
one.write_bytes(rom,8);
one.write(0xBE);
one.read_bytes(resp,9);

//Serial1.println("t ");
//for(int i=0;i<9;i++)
//{
//   Serial1.println(resp[i],HEX);

//}

 byte MSB = resp[1];
  byte LSB = resp[0];

  float tempRead = ((MSB << 8) | LSB); //using two's compliment
  float TemperatureSum = tempRead / 16;
  Serial1.print("Temp ");
  Serial1.println(TemperatureSum);

delay(100);
}