contiki/platform/zoul/dev/sht25.c

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/*
* 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.
*
*/
/*---------------------------------------------------------------------------*/
/**
* \addtogroup zoul-sht25-sensor
* @{
*
* \file
* SHT25 temperature and humidity sensor driver
* \author
* Antonio Lignan <alinan@zolertia.com>
*/
/*---------------------------------------------------------------------------*/
#include <stdio.h>
#include "contiki.h"
#include "dev/i2c.h"
#include "dev/sht25.h"
#include "lib/sensors.h"
/*---------------------------------------------------------------------------*/
#define DEBUG 0
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#if DEBUG
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#endif
/*---------------------------------------------------------------------------*/
static uint8_t enabled;
static uint8_t user_reg;
/*---------------------------------------------------------------------------*/
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, uint8_t num)
{
if((buf == NULL) || (num <= 0)) {
return SHT25_ERROR;
}
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i2c_master_enable();
if(i2c_single_send(SHT25_ADDR, reg) == I2C_MASTER_ERR_NONE) {
if(i2c_burst_receive(SHT25_ADDR, buf, num) == I2C_MASTER_ERR_NONE) {
return SHT25_SUCCESS;
}
}
return SHT25_ERROR;
}
/*---------------------------------------------------------------------------*/
static int16_t
sht25_convert(uint8_t variable, uint16_t value)
{
int16_t rd;
uint32_t buff;
/* Clear the status bits */
buff = (uint32_t)(value & ~SHT25_STATUS_BITS_MASK);
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 int
sht25_read(uint8_t variable, uint16_t *rd)
{
uint8_t buf[2];
uint16_t raw;
if((variable != SHT25_VAL_TEMP) && (variable != SHT25_VAL_HUM)) {
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PRINTF("SHT25: invalid sensor requested\n");
return SHT25_ERROR;
}
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if(sht25_read_reg(variable, buf, 2) == SHT25_SUCCESS) {
raw = (buf[0] << 8) + buf[1];
*rd = sht25_convert(variable, raw);
return SHT25_SUCCESS;
}
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PRINTF("SHT25: failed to read sensor\n");
return SHT25_ERROR;
}
/*---------------------------------------------------------------------------*/
static int
sht25_write_reg(uint8_t *buf, uint8_t num)
{
if((buf == NULL) || (num <= 0)) {
PRINTF("SHT25: invalid write values\n");
return SHT25_ERROR;
}
i2c_master_enable();
if(i2c_burst_send(SHT25_ADDR, buf, num) == I2C_MASTER_ERR_NONE) {
return SHT25_SUCCESS;
}
return SHT25_ERROR;
}
/*---------------------------------------------------------------------------*/
static int
sht25_read_user_register(void)
{
if(sht25_read_reg(SHT2X_UREG_READ, &user_reg, 1) == SHT25_SUCCESS) {
PRINTF("SHT25: user register 0x%02X\n", user_reg);
return SHT25_SUCCESS;
}
PRINTF("SHT25: failed to read user register\n");
return SHT25_ERROR;
}
/*---------------------------------------------------------------------------*/
static int
value(int type)
{
uint16_t val;
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if(!enabled) {
PRINTF("SHT25: sensor not started\n");
return SHT25_ERROR;
}
if((type != SHT25_VAL_TEMP) && (type != SHT25_VAL_HUM) &&
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(type != SHT25_VOLTAGE_ALARM)) {
PRINTF("SHT25: invalid value requested\n");
return SHT25_ERROR;
}
if(type == SHT25_VOLTAGE_ALARM) {
if(sht25_read_user_register() == SHT25_SUCCESS) {
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return (user_reg & SHT2x_LOW_VOLTAGE_MASK) >> SHT2x_LOW_VOLTAGE_SHIFT;
}
} else {
if(sht25_read(type, &val) == SHT25_SUCCESS) {
return val;
}
}
return SHT25_ERROR;
}
/*---------------------------------------------------------------------------*/
static int
configure(int type, int value)
{
uint8_t buf[2];
if((type != SHT25_ACTIVE) && (type != SHT25_SOFT_RESET) &&
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(type != SHT25_RESOLUTION)) {
PRINTF("SHT25: option not supported\n");
return SHT25_ERROR;
}
switch(type) {
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case SHT25_ACTIVE:
if(value) {
i2c_init(I2C_SDA_PORT, I2C_SDA_PIN, I2C_SCL_PORT, I2C_SCL_PIN,
I2C_SCL_NORMAL_BUS_SPEED);
/* Read the user config register */
if(sht25_read_user_register() == SHT25_SUCCESS) {
enabled = value;
return SHT25_SUCCESS;
}
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}
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case SHT25_SOFT_RESET:
buf[0] = SHT2X_SOFT_RESET;
if(sht25_write_reg(&buf[0], 1) != SHT25_SUCCESS) {
PRINTF("SHT25: failed to reset the sensor\n");
return SHT25_ERROR;
}
clock_delay_usec(SHT25_RESET_DELAY);
return SHT25_SUCCESS;
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case SHT25_RESOLUTION:
if((value != SHT2X_RES_14T_12RH) && (value != SHT2X_RES_12T_08RH) &&
(value != SHT2X_RES_13T_10RH) && (value != SHT2X_RES_11T_11RH)) {
PRINTF("SHT25: invalid resolution value\n");
return SHT25_ERROR;
}
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user_reg &= ~SHT2X_RES_11T_11RH;
user_reg |= value;
buf[0] = SHT2X_UREG_WRITE;
buf[1] = user_reg;
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if(sht25_write_reg(buf, 2) == SHT25_SUCCESS) {
PRINTF("SHT25: new user register value 0x%02X\n", user_reg);
return SHT25_SUCCESS;
}
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default:
return SHT25_ERROR;
}
return SHT25_ERROR;
}
/*---------------------------------------------------------------------------*/
SENSORS_SENSOR(sht25, SHT25_SENSOR, value, configure, status);
/*---------------------------------------------------------------------------*/
/** @} */