/*************************************************** 
  This is a library for the Adafruit PT100/P1000 RTD Sensor w/MAX31865

  Designed specifically to work with the Adafruit RTD Sensor
  ----> https://www.adafruit.com/products/3328

  This sensor uses SPI to communicate, 4 pins are required to  
  interface
  Adafruit invests time and resources providing this open source code, 
  please support Adafruit and open-source hardware by purchasing 
  products from Adafruit!

  Written by Limor Fried/Ladyada for Adafruit Industries.  
  BSD license, all text above must be included in any redistribution
 ****************************************************/

#ifndef ADAFRUIT_MAX31865_H
#define ADAFRUIT_MAX31865_H

#define MAX31856_CONFIG_REG            0x00
#define MAX31856_CONFIG_BIAS           0x80
#define MAX31856_CONFIG_MODEAUTO       0x40
#define MAX31856_CONFIG_MODEOFF        0x00
#define MAX31856_CONFIG_1SHOT          0x20
#define MAX31856_CONFIG_3WIRE          0x10
#define MAX31856_CONFIG_24WIRE         0x00
#define MAX31856_CONFIG_FAULTSTAT      0x02
#define MAX31856_CONFIG_FILT50HZ       0x01
#define MAX31856_CONFIG_FILT60HZ       0x00

#define MAX31856_RTDMSB_REG           0x01
#define MAX31856_RTDLSB_REG           0x02
#define MAX31856_HFAULTMSB_REG        0x03
#define MAX31856_HFAULTLSB_REG        0x04
#define MAX31856_LFAULTMSB_REG        0x05
#define MAX31856_LFAULTLSB_REG        0x06
#define MAX31856_FAULTSTAT_REG        0x07


#define MAX31865_FAULT_HIGHTHRESH     0x80
#define MAX31865_FAULT_LOWTHRESH      0x40
#define MAX31865_FAULT_REFINLOW       0x20
#define MAX31865_FAULT_REFINHIGH      0x10
#define MAX31865_FAULT_RTDINLOW       0x08
#define MAX31865_FAULT_OVUV           0x04


#define RTD_A 3.9083e-3
#define RTD_B -5.775e-7

#if (ARDUINO >= 100)
 #include "Arduino.h"
#else
 #include "WProgram.h"
#endif

typedef enum max31865_numwires { 
  MAX31865_2WIRE = 0,
  MAX31865_3WIRE = 1,
  MAX31865_4WIRE = 0
} max31865_numwires_t;


class Adafruit_MAX31865 {
 public:
  Adafruit_MAX31865(int8_t spi_cs, int8_t spi_mosi, int8_t spi_miso, int8_t spi_clk);
  Adafruit_MAX31865(int8_t spi_cs);

  boolean begin(/*max31865_numwires_t*/ int8_t x = MAX31865_2WIRE);

  uint8_t readFault(void);
  void clearFault(void);
  uint16_t readRTD();


  void setWires(/*max31865_numwires_t*/ int8_t wires);
  void autoConvert(boolean b);
  void enableBias(boolean b);

  float temperature(float RTDnominal, float refResistor);
  float resistance (float RTDnominal, float refResistor);
  
 private:
  int8_t _sclk, _miso, _mosi, _cs;

  void readRegisterN(uint8_t addr, uint8_t buffer[], uint8_t n);

  uint8_t  readRegister8(uint8_t addr);
  uint16_t readRegister16(uint8_t addr);

  void     writeRegister8(uint8_t addr, uint8_t reg);
  uint8_t spixfer(uint8_t addr);
};


#endif