135 lines
4.1 KiB
C
135 lines
4.1 KiB
C
/*
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* Copyright (c) 2015, Zolertia <http://www.zolertia.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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*/
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/**
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* \file
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* SHT25 temperature and humidity sensor driver
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* \author
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* Antonio Lignan <alinan@zolertia.com>
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*/
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#include <stdio.h>
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#include "contiki.h"
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#include "i2cmaster.h"
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#include "dev/sht25.h"
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#include "lib/sensors.h"
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/*---------------------------------------------------------------------------*/
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static uint8_t enabled;
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/*---------------------------------------------------------------------------*/
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static int
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configure(int type, int value)
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{
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if(type != SENSORS_ACTIVE) {
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return SHT25_ERROR;
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}
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if(value) {
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i2c_enable();
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} else {
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i2c_disable();
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}
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enabled = value;
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return 0;
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}
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/*---------------------------------------------------------------------------*/
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static int
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status(int type)
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{
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switch(type) {
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case SENSORS_ACTIVE:
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case SENSORS_READY:
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return enabled;
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}
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return 0;
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}
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/*---------------------------------------------------------------------------*/
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static uint16_t
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sht25_read_reg(uint8_t reg)
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{
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uint8_t buf[] = { 0x00, 0x00 };
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uint16_t retval;
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uint8_t rtx = reg;
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/* transmit the register to read */
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i2c_transmitinit(SHT25_ADDR);
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while(i2c_busy());
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i2c_transmit_n(1, &rtx);
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while(i2c_busy());
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/* receive the data */
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i2c_receiveinit(SHT25_ADDR);
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while(i2c_busy());
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i2c_receive_n(2, &buf[0]);
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while(i2c_busy());
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retval = (uint16_t)(buf[0] << 8 | (buf[1]));
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return retval;
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}
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/*---------------------------------------------------------------------------*/
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static int16_t
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sht25_convert(uint8_t variable, uint16_t value)
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{
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int16_t rd;
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uint32_t buff;
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buff = (uint32_t)value;
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if(variable == SHT25_VAL_TEMP) {
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buff *= 17572;
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buff = buff >> 16;
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rd = (int16_t)buff - 4685;
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} else {
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buff *= 12500;
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buff = buff >> 16;
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rd = (int16_t)buff - 600;
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rd = (rd > 10000) ? 10000 : rd;
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}
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return rd;
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}
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/*---------------------------------------------------------------------------*/
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static int16_t
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sht25_read(uint8_t variable)
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{
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int16_t rd;
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uint16_t raw;
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if((variable != SHT25_VAL_TEMP) && (variable != SHT25_VAL_HUM)) {
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return SHT25_ERROR;
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}
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raw = sht25_read_reg(variable);
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rd = sht25_convert(variable, raw);
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return rd;
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}
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/*---------------------------------------------------------------------------*/
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static int
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value(int type)
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{
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return sht25_read(type);
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}
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/*---------------------------------------------------------------------------*/
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SENSORS_SENSOR(sht25, SHT25_SENSOR, value, configure, status);
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/*---------------------------------------------------------------------------*/
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