File content as of revision 0:c0bdc272d5da:

/*
 * mbed library for NTC analog pin that translates an A:D input
 *     voltage to a temperature value
 *     topology:  Vref -> SeriesRes -> A:D -> NTC -> GND
*/

#ifndef        MBED_NTC
#define        MBED_NTC

    /** 
     * Private data structure for NTC data values.
     * 
    **/
    typedef struct {
        float vref;         /*!< Referense voltage*/
        float ad_resolution; /*!< A:D resolution*/
        int ntc_res;        /*!< NTC resistance value at 25C*/
        int ntc_tol;        /*!< NTC initial tolerance %*/
        int ntc_beta_2550;  /*!< NTC Beta, B25/50*/
        int ntc_beta_2580;  /*!< NTC Beta, B25/80*/
        int ntc_beta_2585;  /*!< NTC Beta, B25/85*/
        int ntc_beta_25100; /*!< NTC Beta, B25/100*/
        int ntc_beta_tol;   /*!< NTC Beta tolerance %*/
        int sres_res;       /*!< Series resistor value*/
        int sres_tol;       /*!< Series resistor tolerance %*/
        int sres_ppm;       /*!< Series resistor tempco in ppm*/
    } NTC_TypeDef;

    /** 
     * Default values for data structure above
     * 
    **/
    const NTC_TypeDef ntc_std_paramtr = {
        // Vref
        3.0f,               // Vref
        16384.0f,           // A:D resolution
        // muRata NCP15XH103J03RC
        20000,              // NTC resistance
        3,                  // NTC initial tolerance
        3300,               // NTC B25/50
        3322,               // NTC B25/80
        3333,               // NTC B25/85
        3344,               // NTC B25/100
        2,                  // NTC beta tolerance
        // 3.32k 1% 100ppm
        4750,               // Series resistor value
        5,                  // Series resistor tolerance
        300                 // Series Resistor tempco ppm
    };

    /** OpAmp A:D 
     *
     * @code
     *      //
     *      //
     * @endcode
     */
 
class NTC
{
public:
    /** 
     * NTC Beta curves to choose from for Temperature calculations
     * 
    **/
    enum ntcBetaCurve {
        B25_50,  /*!<  use B25/50 curve */
        B25_80,  /*!<  use B25/80 curve */
        B25_85,  /*!<  use B25/85 curve */
        B25_100, /*!<  use B25/100 curve */
    };

    /** Configure gpio pin
      * @param A:D I/O pin
      * @param parameters for NTC (NTC_TypeDef)
      */
    NTC(PinName p_ana, const NTC_TypeDef *ntc_parameter);
    
    /** Configure gpio pin
      * @param A:D I/O pin
      * uses default parameters
      */
    NTC(PinName p_ana);
    
    /** Read A:D register value
      * @param none
      * @return A:D value from 0-65535
      */
    uint16_t read_ad_reg();
    
    /** Get the NTC resistance value
      * @param none
      * @return resistance of NTC at 25C
      */
    int get_ntc_res();
    
    /** Get the NTC beta value B25/50
      * @param none
      * @return beta
      */
    int get_ntc_beta_2550();
        
    /** Get the NTC beta value B25/80
      * @param none
      * @return beta
      */
    int get_ntc_beta_2580();
        
    /** Get the NTC beta value B25/85
      * @param none
      * @return beta
      */
    int get_ntc_beta_2585();
              
    /** Get the NTC beta value B25/100
      * @param none
      * @return beta
      */
    int get_ntc_beta_25100();
        
    /** Get the resistance value for the series resistor
      * @param none
      * @return resistance of series resistor
      */
    int get_series_res();
    
    /** calculate NTC resistance based on A:D reading
      * @param none
      * @param din optional read from read_ad_reg().
      * @param din if missing or 0, read_ad_reg() is executed first.
      * @param din if != 0, then local value of rawdata is used.
      * @return resistance of NTC
      */
    float get_ntc_res_viaAD(uint16_t din = NULL);
      
    /** calculate NTC temperaure
      * @param curve Beta curve to use. See ntcBetaCurve {};
      * @param din optional read from read_ad_reg().
      * @param din if missing or 0, read_ad_reg() is executed first.
      * @param din if != 0, then local value of rawdata is used.
      * @return temperature of NTC
      */
    float get_ntc_temp(int curve, uint16_t din = NULL);
    
protected:
    AnalogIn  _ana;

private:
    NTC_TypeDef ntc_set_data;
    uint16_t rawdata;

};

#endif  //  MBED_NTC