Contiki-NG
dht22.h
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1 /*
2  * Copyright (c) 2016, Zolertia - http://www.zolertia.com
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  * notice, this list of conditions and the following disclaimer in the
12  * documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the Institute nor the names of its contributors
14  * may be used to endorse or promote products derived from this software
15  * without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * This file is part of the Contiki operating system.
30  *
31  */
32 /*---------------------------------------------------------------------------*/
33 /**
34  * \addtogroup zoul-sensors
35  * @{
36  *
37  * \defgroup zoul-dht22 DHT22 temperature and humidity sensor
38  *
39  * Driver for the DHT22 temperature and humidity sensor
40  * @{
41  *
42  * \file
43  * Header file for the DHT22 temperature and humidity sensor
44  */
45 /*---------------------------------------------------------------------------*/
46 #include "lib/sensors.h"
47 /*---------------------------------------------------------------------------*/
48 #ifndef DHT22_H_
49 #define DHT22_H_
50 /* -------------------------------------------------------------------------- */
51 /**
52  * \name DHT22 default pin and port
53  * @{
54  */
55 #ifdef DHT22_CONF_PIN
56 #define DHT22_PIN DHT22_CONF_PIN
57 #else
58 #define DHT22_PIN 5
59 #endif
60 #ifdef DHT22_CONF_PORT
61 #define DHT22_PORT DHT22_CONF_PORT
62 #else
63 #define DHT22_PORT GPIO_A_NUM
64 #endif
65 /** @} */
66 /* -------------------------------------------------------------------------- */
67 /**
68  * \name DHT22 available commands
69  * @{
70  */
71 #define DHT22_READ_TEMP 0x01
72 #define DHT22_READ_HUM 0x02
73 #define DHT22_READ_ALL 0x03
74 /** @} */
75 /* -------------------------------------------------------------------------- */
76 /**
77  * \name DHT22 return types
78  * @{
79  */
80 #define DHT22_ERROR (-1)
81 #define DHT22_SUCCESS 0x00
82 #define DHT22_BUSY 0xFF
83 /** @} */
84 /* -------------------------------------------------------------------------- */
85 /**
86  * \name DHT22 constants
87  * @{
88  */
89 #define DHT22_BUFFER 5 /**< Buffer to store the samples */
90 #define DHT22_COUNT 8 /**< Minimum ticks to detect a "1" bit */
91 #define DHT22_MAX_TIMMING 85 /**< Maximum ticks in a single operation */
92 #define DHT22_READING_DELAY 1 /**< 1 us */
93 #define DHT22_READY_TIME 40 /**< 40 us */
94 #define DHT22_START_TIME (RTIMER_SECOND / 50) /**< 20 ms */
95 #define DHT22_AWAKE_TIME (RTIMER_SECOND / 4) /**< 250 ms */
96 /** @} */
97 /* -------------------------------------------------------------------------- */
98 /**
99  * \name DHT22 auxiliary functions
100  * @{
101  */
102 int16_t dht22_read_all(int16_t *temperature, int16_t *humidity);
103 /** @} */
104 /* -------------------------------------------------------------------------- */
105 #define DHT22_SENSOR "DHT22 sensor"
106 /* -------------------------------------------------------------------------- */
107 extern const struct sensors_sensor dht22;
108 /* -------------------------------------------------------------------------- */
109 #endif /* DHT22_H_ */
110 /* -------------------------------------------------------------------------- */
111 /**
112  * @}
113  * @}
114  */