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115 lines
3.0 KiB
C
115 lines
3.0 KiB
C
/*
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* Copyright 2015 Ludwig Ortmann, Christian Mehlis
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @defgroup driver_dht DHT Family of Humidity and Temperature Sensors
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* @ingroup drivers
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* @brief Device driver for the DHT Family of humidity
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* and temperature sensors
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*
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* @{
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*
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* @file
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* @brief Device driver interface for the DHT family of humidity
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* and temperature sensors
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*
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* @author Ludwig Ortmann <ludwig.ortmann@fu-berlin.de
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* @author Christian Mehlis <mehlis@inf.fu-berlin.de>
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*/
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#ifndef DHT_H
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#define DHT_H
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#include <stdint.h>
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#include "periph/gpio.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief data type for storing DHT sensor readings
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*/
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typedef struct {
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uint16_t humidity; /**< relative deca-humidity */
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uint16_t temperature; /**< temperature in deca-Celsius */
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} dht_data_t;
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/**
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* @brief device type of the DHT device
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*/
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typedef enum {
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DHT11, /**< DHT11 device identifier */
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DHT22, /**< DHT22 device identifier */
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DHT21 = DHT22 /**< DHT21 device identifier */
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} dht_type_t;
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/**
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* @brief device descriptor for DHT sensor devices
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*/
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typedef struct {
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gpio_t gpio; /**< GPIO pin of the device's data pin */
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dht_type_t type; /**< type of the DHT device */
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} dht_t;
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/**
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* @brief initialize a new DHT device
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*
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* @param[in] dev device descriptor of a DHT device
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* @param[in] type type of the DHT device
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* @param[in] gpio GPIO pin the device's data pin is connected to
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*
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* @return 0 on success
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* @return -1 on error
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*/
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int dht_init(dht_t *dev, dht_type_t type, gpio_t gpio);
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/**
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* @brief read sensor data from device
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*
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* @param[in] dev device descriptor of a DHT device
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* @param[out] relhum pointer to relative humidity in g/m^3
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* @param[out] temp pointer to temperature in degrees Celsius
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*
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* @return 0 on success
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* @return -1 on error
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*/
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int dht_read(dht_t *dev, float *relhum, float *temp);
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/**
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* @brief read sensor data from device
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*
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* @note When reading fails and the function indicates an error,
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* data will contain garbage.
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*
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* @param[in] dev device descriptor of a DHT device
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* @param[in] data pointer to DHT data object
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*
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* @return 0 on success
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* @return -1 on checksum error
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*/
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int dht_read_raw(dht_t *dev, dht_data_t *data);
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/**
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* @brief parse raw sensor data into relative humidity and Celsius
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*
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* @param[in] dev device descriptor of a DHT device
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* @param[in] data sensor data
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* @param[out] relhum pointer to relative humidity in g/m^3
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* @param[out] temp pointer to temperature in degrees Celsius
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*/
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void dht_parse(dht_t *dev, dht_data_t *data, float *relhum, float *temp);
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#ifdef __cplusplus
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}
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#endif
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#endif /* DHT_H */
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/** @} */
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