Contiki-NG
sht25.c
Go to the documentation of this file.
1/*
2 * Copyright (c) 2015, 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 * \file
34 * SHT25 temperature and humidity sensor driver
35 * \author
36 * Antonio Lignan <alinan@zolertia.com>
37 */
38#include <stdio.h>
39#include "contiki.h"
40#include "i2cmaster.h"
41#include "dev/sht25.h"
42#include "lib/sensors.h"
43/*---------------------------------------------------------------------------*/
44static uint8_t enabled;
45/*---------------------------------------------------------------------------*/
46static int
47configure(int type, int value)
48{
49 if(type != SENSORS_ACTIVE) {
50 return SHT25_ERROR;
51 }
52 if(value) {
53 i2c_enable();
54 } else {
55 i2c_disable();
56 }
57 enabled = value;
58 return 0;
59}
60/*---------------------------------------------------------------------------*/
61static int
62status(int type)
63{
64 switch(type) {
65 case SENSORS_ACTIVE:
66 case SENSORS_READY:
67 return enabled;
68 }
69 return 0;
70}
71/*---------------------------------------------------------------------------*/
72static uint16_t
73sht25_read_reg(uint8_t reg)
74{
75 uint8_t buf[] = { 0x00, 0x00 };
76 uint16_t retval;
77 uint8_t rtx = reg;
78
79 /* transmit the register to read */
80 i2c_transmitinit(SHT25_ADDR);
81 while(i2c_busy());
82 i2c_transmit_n(1, &rtx);
83 while(i2c_busy());
84 /* receive the data */
85 i2c_receiveinit(SHT25_ADDR);
86 while(i2c_busy());
87 i2c_receive_n(2, &buf[0]);
88 while(i2c_busy());
89
90 retval = (uint16_t)(buf[0] << 8 | (buf[1]));
91 return retval;
92}
93/*---------------------------------------------------------------------------*/
94static int16_t
95sht25_convert(uint8_t variable, uint16_t value)
96{
97 int16_t rd;
98 uint32_t buff;
99 buff = (uint32_t)value;
100 if(variable == SHT25_VAL_TEMP) {
101 buff *= 17572;
102 buff = buff >> 16;
103 rd = (int16_t)buff - 4685;
104 } else {
105 buff *= 12500;
106 buff = buff >> 16;
107 rd = (int16_t)buff - 600;
108 rd = (rd > 10000) ? 10000 : rd;
109 }
110 return rd;
111}
112/*---------------------------------------------------------------------------*/
113static int16_t
114sht25_read(uint8_t variable)
115{
116 int16_t rd;
117 uint16_t raw;
118
119 if((variable != SHT25_VAL_TEMP) && (variable != SHT25_VAL_HUM)) {
120 return SHT25_ERROR;
121 }
122 raw = sht25_read_reg(variable);
123 rd = sht25_convert(variable, raw);
124 return rd;
125}
126/*---------------------------------------------------------------------------*/
127static int
128value(int type)
129{
130 return sht25_read(type);
131}
132/*---------------------------------------------------------------------------*/
133SENSORS_SENSOR(sht25, SHT25_SENSOR, value, configure, status);
134/*---------------------------------------------------------------------------*/
i2cmaster.h
I2C communication device driver header file for Zolertia Z1 sensor node.