243 lines
7.1 KiB
C
243 lines
7.1 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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/**
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* \addtogroup zoul-sht25-sensor
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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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/*---------------------------------------------------------------------------*/
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#include <stdio.h>
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#include "contiki.h"
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#include "dev/i2c.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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#define DEBUG 0
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#if DEBUG
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#define PRINTF(...) printf(__VA_ARGS__)
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#else
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#define PRINTF(...)
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#endif
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/*---------------------------------------------------------------------------*/
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static uint8_t enabled;
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static uint8_t user_reg;
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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, uint8_t *buf, uint8_t num)
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{
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if((buf == NULL) || (num <= 0)) {
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return SHT25_ERROR;
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}
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i2c_master_enable();
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if(i2c_single_send(SHT25_ADDR, reg) == I2C_MASTER_ERR_NONE) {
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if(i2c_burst_receive(SHT25_ADDR, buf, num) == I2C_MASTER_ERR_NONE) {
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return SHT25_SUCCESS;
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}
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}
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return SHT25_ERROR;
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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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/* Clear the status bits */
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buff = (uint32_t)(value & ~SHT25_STATUS_BITS_MASK);
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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 int
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sht25_read(uint8_t variable, uint16_t *rd)
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{
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uint8_t buf[2];
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uint16_t raw;
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if((variable != SHT25_VAL_TEMP) && (variable != SHT25_VAL_HUM)) {
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PRINTF("SHT25: invalid sensor requested\n");
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return SHT25_ERROR;
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}
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if(sht25_read_reg(variable, buf, 2) == SHT25_SUCCESS) {
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raw = (buf[0] << 8) + buf[1];
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*rd = sht25_convert(variable, raw);
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return SHT25_SUCCESS;
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}
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PRINTF("SHT25: failed to read sensor\n");
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return SHT25_ERROR;
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}
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/*---------------------------------------------------------------------------*/
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static int
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sht25_write_reg(uint8_t *buf, uint8_t num)
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{
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if((buf == NULL) || (num <= 0)) {
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PRINTF("SHT25: invalid write values\n");
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return SHT25_ERROR;
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}
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i2c_master_enable();
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if(i2c_burst_send(SHT25_ADDR, buf, num) == I2C_MASTER_ERR_NONE) {
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return SHT25_SUCCESS;
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}
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return SHT25_ERROR;
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}
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/*---------------------------------------------------------------------------*/
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static int
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sht25_read_user_register(void)
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{
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if(sht25_read_reg(SHT2X_UREG_READ, &user_reg, 1) == SHT25_SUCCESS) {
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PRINTF("SHT25: user register 0x%02X\n", user_reg);
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return SHT25_SUCCESS;
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}
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PRINTF("SHT25: failed to read user register\n");
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return SHT25_ERROR;
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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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uint16_t val;
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if(!enabled) {
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PRINTF("SHT25: sensor not started\n");
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return SHT25_ERROR;
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}
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if((type != SHT25_VAL_TEMP) && (type != SHT25_VAL_HUM) &&
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(type != SHT25_VOLTAGE_ALARM)) {
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PRINTF("SHT25: invalid value requested\n");
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return SHT25_ERROR;
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}
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if(type == SHT25_VOLTAGE_ALARM) {
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if(sht25_read_user_register() == SHT25_SUCCESS) {
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return (user_reg & SHT2x_LOW_VOLTAGE_MASK) >> SHT2x_LOW_VOLTAGE_SHIFT;
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}
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} else {
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if(sht25_read(type, &val) == SHT25_SUCCESS) {
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return val;
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}
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}
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return SHT25_ERROR;
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}
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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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uint8_t buf[2];
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if((type != SHT25_ACTIVE) && (type != SHT25_SOFT_RESET) &&
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(type != SHT25_RESOLUTION)) {
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PRINTF("SHT25: option not supported\n");
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return SHT25_ERROR;
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}
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switch(type) {
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case SHT25_ACTIVE:
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if(value) {
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i2c_init(I2C_SDA_PORT, I2C_SDA_PIN, I2C_SCL_PORT, I2C_SCL_PIN,
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I2C_SCL_NORMAL_BUS_SPEED);
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/* Read the user config register */
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if(sht25_read_user_register() == SHT25_SUCCESS) {
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enabled = value;
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return SHT25_SUCCESS;
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}
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}
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case SHT25_SOFT_RESET:
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buf[0] = SHT2X_SOFT_RESET;
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if(sht25_write_reg(&buf[0], 1) != SHT25_SUCCESS) {
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PRINTF("SHT25: failed to reset the sensor\n");
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return SHT25_ERROR;
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}
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clock_delay_usec(SHT25_RESET_DELAY);
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return SHT25_SUCCESS;
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case SHT25_RESOLUTION:
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if((value != SHT2X_RES_14T_12RH) && (value != SHT2X_RES_12T_08RH) &&
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(value != SHT2X_RES_13T_10RH) && (value != SHT2X_RES_11T_11RH)) {
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PRINTF("SHT25: invalid resolution value\n");
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return SHT25_ERROR;
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}
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user_reg &= ~SHT2X_RES_11T_11RH;
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user_reg |= value;
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buf[0] = SHT2X_UREG_WRITE;
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buf[1] = user_reg;
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if(sht25_write_reg(buf, 2) == SHT25_SUCCESS) {
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PRINTF("SHT25: new user register value 0x%02X\n", user_reg);
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return SHT25_SUCCESS;
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}
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default:
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return SHT25_ERROR;
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}
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return SHT25_ERROR;
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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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/** @} */
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