first commit

libraries/DHT20/DHT20.h

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+#pragma once
+//
+//    FILE: DHT20.h
+//  AUTHOR: Rob Tillaart
+// PURPOSE: Arduino library for DHT20 I2C temperature and humidity sensor.
+// VERSION: 0.3.1
+//     URL: https://github.com/RobTillaart/DHT20
+//
+
+//  Always check datasheet - front view
+//
+//          +--------------+
+//  VDD ----| 1            |
+//  SDA ----| 2    DHT20   |
+//  GND ----| 3            |
+//  SCL ----| 4            |
+//          +--------------+
+
+
+#include "Arduino.h"
+#include "Wire.h"
+
+#define DHT20_LIB_VERSION                    (F("0.3.1"))
+
+#define DHT20_OK                             0
+#define DHT20_ERROR_CHECKSUM                -10
+#define DHT20_ERROR_CONNECT                 -11
+#define DHT20_MISSING_BYTES                 -12
+#define DHT20_ERROR_BYTES_ALL_ZERO          -13
+#define DHT20_ERROR_READ_TIMEOUT            -14
+#define DHT20_ERROR_LASTREAD                -15
+
+
+class DHT20
+{
+public:
+  //  CONSTRUCTOR
+  //  fixed address 0x38
+  DHT20(TwoWire *wire = &Wire);
+
+  bool     begin();
+  bool     isConnected();
+  uint8_t  getAddress();
+
+
+  //  ASYNCHRONUOUS CALL
+  //  trigger acquisition.
+  int      requestData();
+  //  read the raw data.
+  int      readData();
+  //  converts raw data bits to temperature and humidity.
+  int      convert();
+
+
+  //  SYNCHRONOUS CALL
+  //  blocking read call to read + convert data
+  int      read();
+  //  access the converted temperature & humidity
+  float    getHumidity();
+  float    getTemperature();
+
+
+  //  OFFSET  1st order adjustments
+  void     setHumOffset(float offset = 0);
+  void     setTempOffset(float offset = 0);
+  float    getHumOffset();
+  float    getTempOffset();
+
+
+  //  READ STATUS
+  uint8_t  readStatus();
+  //  3 wrapper functions around readStatus()
+  bool     isCalibrated();
+  bool     isMeasuring();
+  bool     isIdle();
+  //  status from last read()
+  int      internalStatus();
+
+
+  //  TIMING
+  uint32_t lastRead();
+  uint32_t lastRequest();
+
+
+  //  RESET  (new since 0.1.4)
+  //  use with care
+  //  returns number of registers reset => must be 3
+  //  3     = OK
+  //  0,1,2 = error.
+  //  255   = no reset needed.
+  //  See datasheet 7.4 Sensor Reading Process, point 1
+  //  use with care
+  uint8_t  resetSensor();
+
+
+private:
+  float    _humidity;
+  float    _temperature;
+  float    _humOffset;
+  float    _tempOffset;
+
+  uint8_t  _status;
+  uint32_t _lastRequest;
+  uint32_t _lastRead;
+  uint8_t  _bits[7];
+
+  uint8_t  _crc8(uint8_t *ptr, uint8_t len);
+
+  //  use with care
+  bool     _resetRegister(uint8_t reg);
+
+  TwoWire* _wire;
+};
+
+
+//  -- END OF FILE --
+