Adafruit_SGP40.h

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#ifndef ADAFRUIT_SGP40_H
#define ADAFRUIT_SGP40_H

#include <Adafruit_BusIO_Register.h>
#include <Adafruit_I2CDevice.h>

#include "Arduino.h"
extern "C" {
#include "sensirion_arch_config.h"
#include "sensirion_voc_algorithm.h"
};

// the i2c address
#define SGP40_I2CADDR_DEFAULT 0x59 

// commands and constants
#define SGP40_FEATURESET 0x0020    
#define SGP40_CRC8_POLYNOMIAL 0x31 
#define SGP40_CRC8_INIT 0xFF       
#define SGP40_WORD_LEN 2           


class Adafruit_SGP40 {
 public:
  Adafruit_SGP40();
  bool begin(TwoWire* theWire = &Wire);
  bool selfTest(void);

  bool softReset();
  bool heaterOff();
  uint16_t measureRaw(float temperature = 25, float humidity = 50);
  int32_t measureVocIndex(float temperature = 25, float humidity = 50);

  uint16_t serialnumber[3];

 private:
  Adafruit_I2CDevice* i2c_dev = NULL; 
  void write(uint8_t address, uint8_t* data, uint8_t n);
  void read(uint8_t address, uint8_t* data, uint8_t n);
  bool readWordFromCommand(uint8_t command[], uint8_t commandLength,
                           uint16_t delayms, uint16_t* readdata = NULL,
                           uint8_t readlen = 0);
  uint8_t generateCRC(uint8_t data[], uint8_t datalen);

  VocAlgorithmParams voc_algorithm_params;
};
#endif // ndef ADAFRUIT_SGP40_H