/*
* The BSD License (3-clause license)
*
* Copyright (c) 2017 Gunar Schorcht (https://github.com/gschorcht
* 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 copyright holder 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
*/
/**
* Driver for Sensirion SHT3x digital temperature and humity sensor
* connected to I2C
*
* Part of esp-open-rtos
*/
#include <string.h>
#include "sht3x.h"
#include "FreeRTOS.h"
#include "task.h"
#include "espressif/esp_common.h"
#include "espressif/sdk_private.h"
#define SHT3x_BG_TASK_PRIORITY 9
#define SHT3x_STATUS_CMD 0xF32D
#define SHT3x_CLEAR_STATUS_CMD 0x3041
#define SHT3x_RESET_CMD 0x30A2
#define SHT3x_MEASURE_ONE_SHOT_CMD 0x2C06
#define SHT3x_MEASURE_PERIODIC_1_CMD 0x2130
#define SHT3x_MEASURE_PERIODIC_2_CMD 0x2236
#define SHT3x_MEASURE_PERIODIC_4_CMD 0x2434
#define SHT3x_MEASURE_PERIODIC_10_CMD 0x2737
#define SHT3x_FETCH_DATA_CMD 0xE000
#ifdef SHT3x_DEBUG
#define debug(s, ...) printf("%s: " s "\n", "SHT3x", ## __VA_ARGS__)
#else
#define debug(s, ...)
#endif
sht3x_sensor_t sht3x_sensors[SHT3x_MAX_SENSORS];
static bool sht3x_send_command(uint32_t id, uint16_t cmd)
{
uint8_t data[2] = { cmd / 256, cmd % 256 };
debug("%s: Send MSB command byte %0x", __FUNCTION__, data[0]);
debug("%s: Send LSB command byte %0x", __FUNCTION__, data[1]);
int error = i2c_slave_write(sht3x_sensors[id].bus, sht3x_sensors[id].addr, 0, data, 2);
if (error)
{
printf("%s: Error %d on write command %0x to i2c slave on bus %d with addr %0x.\n",
__FUNCTION__, error, cmd, sht3x_sensors[id].bus, sht3x_sensors[id].addr);
return false;
}
return true;
}
static bool sht3x_read_data(uint32_t id, uint8_t *data, uint32_t len)
{
int error = i2c_slave_read(sht3x_sensors[id].bus, sht3x_sensors[id].addr, 0, data, len);
if (error)
{
printf("%s: Error %d on read %d byte from i2c slave on bus %d with addr %0x.\n",
__FUNCTION__, error, len, sht3x_sensors[id].bus, sht3x_sensors[id].addr);
return false;
}
# ifdef SHT3x_DEBUG
printf("SHT3x: %s: Read following bytes: ", __FUNCTION__);
for (int i=0; i < len; i++)
printf("%0x ", data[i]);
printf("\n");
# endif
return true;
}
static bool sht3x_is_available (uint32_t sensor)
{
uint8_t data[3];
if (!sht3x_send_command(sensor, SHT3x_STATUS_CMD))
{
debug("Called from %s", __FUNCTION__);
return false;
}
if (!sht3x_read_data(sensor, data, 3))
{
debug("Called from %s", __FUNCTION__);
return false;
}
return true;
}
static bool sht3x_valid_sensor (uint32_t sensor, const char* function)
{
if (sensor < 0 || sensor > SHT3x_MAX_SENSORS)
{
debug("%s: Wrong sensor id %d.", function, sensor);
return false;
}
if (!sht3x_sensors[sensor].active)
{
debug("%s: Sensor with id %d is not active.", function, sensor);
return false;
}
return true;
}
static void sht3x_compute_values (uint8_t id, uint8_t* data)
{
sht3x_value_set_t act;
sht3x_value_set_t avg = sht3x_sensors[id].average;
float w = sht3x_sensors[id].average_weight;
act.temperature_c = ((((data[0] * 256.0) + data[1]) * 175) / 65535.0) - 45;
act.temperature_f = ((((data[0] * 256.0) + data[1]) * 347) / 65535.0) - 49;
act.humidity = ((((data[3] * 256.0) + data[4]) * 100) / 65535.0);
if (sht3x_sensors[id].average_first_measurement || !sht3x_sensors[id].average_computation)
{
sht3x_sensors[id].average_first_measurement = false;
avg = act;
}
else
{
avg.temperature_c = w * act.temperature_c + (1-w) * avg.temperature_c;
avg.temperature_f = w * act.temperature_f + (1-w) * avg.temperature_f;
avg.humidity = w * act.humidity + (1-w) * avg.humidity;
}
sht3x_sensors[id].actual = act;
sht3x_sensors[id].average = avg;
}
static void sht3x_background_task (void *pvParameters)
{
uint8_t data[6];
uint32_t sensor = (uint32_t)pvParameters;
while (1)
{
// debug("%.3f Sensor %d: %s", (double)sdk_system_get_time()*1e-3, sensor, __FUNCTION__);
if (sht3x_valid_sensor(sensor, __FUNCTION__) &&
sht3x_send_command(sensor, SHT3x_MEASURE_ONE_SHOT_CMD))
{
vTaskDelay (20 / portTICK_PERIOD_MS);
if (sht3x_read_data(sensor, data, 6))
{
sht3x_compute_values(sensor, data);
// debug("%.2f C, %.2f F, %.2f",
// sht3x_sensors[sensor].actual.temperature_c,
// sht3x_sensors[sensor].actual.temperature_f,
// sht3x_sensors[sensor].actual.humidity);
if (sht3x_sensors[sensor].cb_function)
sht3x_sensors[sensor].cb_function(sensor,
sht3x_sensors[sensor].actual,
sht3x_sensors[sensor].average);
}
else
debug("Called from %s", __FUNCTION__);
vTaskDelay((sht3x_sensors[sensor].period-20) / portTICK_PERIOD_MS);
}
else
{
debug("Called from %s", __FUNCTION__);
vTaskDelay(sht3x_sensors[sensor].period / portTICK_PERIOD_MS);
}
}
}
bool sht3x_init()
{
for (int id=0; id < SHT3x_MAX_SENSORS; id++)
sht3x_sensors[id].active = false;
return true;
}
uint32_t sht3x_create_sensor(uint8_t bus, uint8_t addr)
{
static uint32_t id;
static char bg_task_name[20];
// search for first free sensor data structure
for (id=0; id < SHT3x_MAX_SENSORS; id++)
{
debug("%s: id=%d active=%d", __FUNCTION__, id, sht3x_sensors[id].active);
if (!sht3x_sensors[id].active)
break;
}
debug("%s: id=%d", __FUNCTION__, id);
if (id == SHT3x_MAX_SENSORS)
{
debug("%s: No more sensor data structures available.", __FUNCTION__);
return -1;
}
// init sensor data structure
sht3x_sensors[id].bus = bus;
sht3x_sensors[id].addr = addr;
sht3x_sensors[id].period = 1000;
sht3x_sensors[id].average_computation = true;
sht3x_sensors[id].average_first_measurement = true;
sht3x_sensors[id].average_weight = 0.2;
sht3x_sensors[id].cb_function = NULL;
sht3x_sensors[id].bg_task = NULL;
// check whether sensor is available
if (!sht3x_is_available(id))
return -1;
// clear sensor status register
if (!sht3x_send_command(id, SHT3x_CLEAR_STATUS_CMD))
{
debug("Called from %s", __FUNCTION__);
return -1;
}
snprintf (bg_task_name, 20, "sht3x_bg_task_%d", id);
if (xTaskCreate (sht3x_background_task, bg_task_name, 256, (void*)id,
SHT3x_BG_TASK_PRIORITY,
&sht3x_sensors[id].bg_task) != pdPASS)
{
vTaskDelete(sht3x_sensors[id].bg_task);
printf("%s: Could not create task %s\n", __FUNCTION__, bg_task_name);
return false;
}
sht3x_sensors[id].active = true;
return id;
}
bool sht3x_delete_sensor(uint32_t sensor)
{
if (!sht3x_valid_sensor(sensor, __FUNCTION__))
return false;
sht3x_sensors[sensor].active = false;
if (sht3x_sensors[sensor].bg_task)
vTaskDelete(sht3x_sensors[sensor].bg_task);
return true;
}
bool sht3x_set_measurement_period (uint32_t sensor, uint32_t period)
{
if (!sht3x_valid_sensor(sensor, __FUNCTION__))
return false;
if (period < 20)
debug("%s: Period of %d ms is less than the minimum period of 20 ms for sensor with id %d.", __FUNCTION__, period, sensor);
sht3x_sensors[sensor].period = period;
return true;
}
bool sht3x_set_callback_function (uint32_t sensor, sht3x_cb_function_t user_function)
{
if (!sht3x_valid_sensor(sensor, __FUNCTION__))
return false;
sht3x_sensors[sensor].cb_function = user_function;
debug("%s: Set callback mode done.", __FUNCTION__);
return false;
}
bool sht3x_get_values(uint32_t sensor, sht3x_value_set_t *actual, sht3x_value_set_t *average)
{
if (!sht3x_valid_sensor(sensor, __FUNCTION__))
return false;
if (actual) *actual = sht3x_sensors[sensor].actual;
if (average) *average = sht3x_sensors[sensor].average;
return true;
}
bool sht3x_enable_average_computation (uint32_t sensor, bool enabled)
{
sht3x_sensors[sensor].average_computation = enabled;
sht3x_sensors[sensor].average_first_measurement = enabled;
return true;
}
bool sht3x_set_average_weight (uint32_t sensor, float weight)
{
sht3x_sensors[sensor].average_first_measurement = true;
sht3x_sensors[sensor].average_weight = weight;
return true;
}