ErriezDHT22.h

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/*
 * MIT License
 *
 * Copyright (c) 2018-2020 Erriez
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef ERRIEZ_DHT22_H_
#define ERRIEZ_DHT22_H_

#include <Arduino.h>

// #define DEBUG_PRINT

#define DHT22_MIN_READ_INTERVAL     2000

#define DHT22_NUM_DATA_BITS         (5 * 8)

#ifdef DEBUG_PRINT
  #define DEBUG_PRINTLN(...) { Serial.println(__VA_ARGS__); }
#else
  #define DEBUG_PRINTLN(...) {}
#endif

class DHT22
{
public:
    explicit DHT22(uint8_t pin);
    void begin(uint8_t numSamples=0);
    bool available();
    bool readSensorData();
    int16_t readTemperature();
    int16_t readHumidity();

private:
    unsigned long _lastMeasurementTimestamp;
    uint32_t _maxCycles;
    uint32_t cycles[DHT22_NUM_DATA_BITS * 2];
    uint8_t _data[5];
    bool _statusLastMeasurement;

    uint8_t _numSamples;

    int16_t *_temperatureSamples;
    uint8_t _temperatureSampleIndex;
    uint8_t _numTemperatureSamples;

    int16_t *_humiditySamples;
    uint8_t _humiditySampleIndex;
    uint8_t _numHumiditySamples;

    uint8_t _pin;

#ifdef __AVR
    uint8_t _bit;
    uint8_t _port;
#endif

    bool generateStart();
    bool readBytes();
    uint32_t measurePulseWidth(uint8_t level);
};

#endif // ERRIEZ_DHT22_H_