dht.h
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/*
* Copyright 2015 Ludwig Knüpfer,
* 2015 Christian Mehlis
* 2016 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup drivers_dht DHT Family of Humidity and Temperature Sensors
* @ingroup drivers_sensors
* @brief Device driver for the DHT Family of humidity
* and temperature sensors
*
* @{
*
* @file
* @brief Device driver interface for the DHT family of humidity
* and temperature sensors
*
* @author Ludwig Knüpfer <ludwig.knuepfer@fu-berlin.de
* @author Christian Mehlis <mehlis@inf.fu-berlin.de>
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
*/
#ifndef DHT_H
#define DHT_H
#include <stdint.h>
#include "saul.h"
#include "periph/gpio.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief data type for storing DHT sensor readings
*/
typedef struct {
uint16_t humidity; /**< relative deca-humidity */
uint16_t temperature; /**< temperature in deca-Celsius */
} dht_data_t;
/**
* @brief device type of the DHT device
*/
typedef enum {
DHT11, /**< DHT11 device identifier */
DHT22, /**< DHT22 device identifier */
DHT21 = DHT22 /**< DHT21 device identifier */
} dht_type_t;
/**
* @brief device descriptor for DHT sensor devices
*/
typedef struct {
gpio_t pin; /**< GPIO pin of the device's data pin */
dht_type_t type; /**< type of the DHT device */
gpio_mode_t in_mode; /**< input pin configuration, with or without pull
* resistor */
} dht_t;
/**
* @brief configuration parameters for DHT devices
*/
typedef dht_t dht_params_t;
/**
* @brief export SAUL endpoints
* @{
*/
extern const saul_driver_t dht_temp_saul_driver;
extern const saul_driver_t dht_hum_saul_driver;
/** @} */
/**
* @brief auto-initialize all configured DHT devices
*/
void dht_auto_init(void);
/**
* @brief initialize a new DHT device
*
* @param[out] dev device descriptor of a DHT device
* @param[in] params configuration parameters
*
* @return 0 on success
* @return -1 on error
*/
int dht_init(dht_t *dev, const dht_params_t *params);
/**
* @brief get a new temperature and humidity value from the device
*
* @note if reading fails or checksum is invalid, no new values will be
* written into the result values
*
* @param[in] dev device descriptor of a DHT device
* @param[out] temp temperature value [in °C * 10^-1]
* @param[out] hum relative humidity value [in percent * 10^-1]
*
* @return 0 on success
* @return -1 on checksum error
* @return -2 on parsing error
*/
int dht_read(dht_t *dev, int16_t *temp, int16_t *hum);
#ifdef __cplusplus
}
#endif
#endif /* DHT_H */
/** @} */