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