1525f61fe3
- lookup tables made const to be held in flash - crc8 computation changed to a non table lookup version - measurement duration is now given in ticks and can be used directly for vTaskDelay (documentation and examples changed accordingly)
397 lines
12 KiB
C
397 lines
12 KiB
C
/*
|
|
* Driver for Sensirion SHT3x digital temperature and humidity sensor
|
|
* connected to I2C
|
|
*
|
|
* Part of esp-open-rtos
|
|
*
|
|
* ----------------------------------------------------------------
|
|
*
|
|
* 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_STATUS_CMD 0xF32D
|
|
#define SHT3x_CLEAR_STATUS_CMD 0x3041
|
|
#define SHT3x_RESET_CMD 0x30A2
|
|
#define SHT3x_FETCH_DATA_CMD 0xE000
|
|
#define SHT3x_HEATER_OFF_CMD 0x3066
|
|
|
|
const uint16_t SHT3x_MEASURE_CMD[6][3] = { {0x2c06,0x2c0d,0x2c10}, // [SINGLE_SHOT][H,M,L]
|
|
{0x2032,0x2024,0x202f}, // [PERIODIC_05][H,M,L]
|
|
{0x2130,0x2126,0x212d}, // [PERIODIC_05][H,M,L]
|
|
{0x2236,0x2220,0x222b}, // [PERIODIC_05][H,M,L]
|
|
{0x2234,0x2322,0x2329}, // [PERIODIC_05][H,M,L]
|
|
{0x2737,0x2721,0x272a} }; // [PERIODIC_05][H,M,L]
|
|
|
|
const int32_t SHT3x_MEASURE_DURATION[3] = {3,2,2}; // tick counts [High, Medium, Low]
|
|
|
|
#ifdef SHT3x_DEBUG
|
|
#define debug(s, f, ...) printf("%s %s: " s "\n", "SHT3x", f, ## __VA_ARGS__)
|
|
#define debug_dev(s, f, d, ...) printf("%s %s: bus %d, addr %02x - " s "\n", "SHT3x", f, d->bus, d->addr, ## __VA_ARGS__)
|
|
#else
|
|
#define debug(s, f, ...)
|
|
#define debug_dev(s, f, d, ...)
|
|
#endif
|
|
|
|
#define error(s, f, ...) printf("%s %s: " s "\n", "SHT3x", f, ## __VA_ARGS__)
|
|
#define error_dev(s, f, d, ...) printf("%s %s: bus %d, addr %02x - " s "\n", "SHT3x", f, d->bus, d->addr, ## __VA_ARGS__)
|
|
|
|
/** Forward declaration of function for internal use */
|
|
|
|
static bool sht3x_send_command (sht3x_sensor_t*, uint16_t);
|
|
static bool sht3x_read_data (sht3x_sensor_t*, uint8_t*, uint32_t);
|
|
static bool sht3x_get_status (sht3x_sensor_t*, uint16_t*);
|
|
// static bool sht3x_reset (sht3x_sensor_t*);
|
|
|
|
static uint8_t crc8 (uint8_t data[], int len);
|
|
|
|
/** ------------------------------------------------ */
|
|
|
|
bool sht3x_init_driver()
|
|
{
|
|
return true;
|
|
}
|
|
|
|
|
|
sht3x_sensor_t* sht3x_init_sensor(uint8_t bus, uint8_t addr)
|
|
{
|
|
sht3x_sensor_t* dev;
|
|
|
|
if ((dev = malloc (sizeof(sht3x_sensor_t))) == NULL)
|
|
return NULL;
|
|
|
|
// init sensor data structure
|
|
dev->bus = bus;
|
|
dev->addr = addr;
|
|
dev->mode = single_shot;
|
|
dev->repeatability = high;
|
|
dev->meas_started = false;
|
|
dev->meas_start_tick = 0;
|
|
|
|
dev->active = true;
|
|
|
|
uint16_t status;
|
|
|
|
// check the again the status after clear status command
|
|
if (!sht3x_get_status(dev, &status))
|
|
{
|
|
error_dev ("could not get sensor status", __FUNCTION__, dev);
|
|
free(dev);
|
|
return NULL;
|
|
}
|
|
|
|
debug_dev ("sensor initialized", __FUNCTION__, dev);
|
|
return dev;
|
|
}
|
|
|
|
|
|
int32_t sht3x_start_measurement (sht3x_sensor_t* dev, sht3x_mode_t mode)
|
|
{
|
|
if (!dev || !dev->active) return -1;
|
|
|
|
dev->error_code = SHT3x_OK;
|
|
|
|
// return remaining time when measurement is already running
|
|
if (dev->meas_started)
|
|
{
|
|
debug_dev ("measurement already started", __FUNCTION__, dev);
|
|
dev->error_code = SHT3x_MEAS_ALREADY_RUNNING;
|
|
return sht3x_is_measuring (dev);
|
|
}
|
|
|
|
dev->mode = mode;
|
|
|
|
// start measurement according to selected mode and return an duration estimate
|
|
if (sht3x_send_command(dev, SHT3x_MEASURE_CMD[dev->mode][dev->repeatability]))
|
|
{
|
|
dev->meas_start_tick = xTaskGetTickCount ();
|
|
dev->meas_started = true;
|
|
dev->meas_first = true;
|
|
return SHT3x_MEASURE_DURATION[dev->repeatability]; // in RTOS ticks
|
|
}
|
|
|
|
dev->error_code |= SHT3x_SEND_MEAS_CMD_FAILED;
|
|
return -1; // on error
|
|
}
|
|
|
|
|
|
// returns 0 when finished, -1 on error, remaining measurement time otherwise
|
|
int32_t sht3x_is_measuring (sht3x_sensor_t* dev)
|
|
{
|
|
if (!dev || !dev->active) return -1;
|
|
|
|
dev->error_code = SHT3x_OK;
|
|
|
|
if (!dev->meas_started)
|
|
{
|
|
error_dev ("measurement not started", __FUNCTION__, dev);
|
|
dev->error_code = SHT3x_MEAS_NOT_STARTED;
|
|
return -1;
|
|
}
|
|
|
|
// computation is necessary in periodic mode only for first measurement
|
|
// in single shot mode every measurment is the first one
|
|
if (!dev->meas_first)
|
|
return 0;
|
|
|
|
uint32_t elapsed_time;
|
|
|
|
elapsed_time = (xTaskGetTickCount() - dev->meas_start_tick); // in RTOS ticks
|
|
|
|
if (elapsed_time >= SHT3x_MEASURE_DURATION[dev->repeatability])
|
|
return 0;
|
|
else
|
|
return SHT3x_MEASURE_DURATION[dev->repeatability] - elapsed_time;
|
|
}
|
|
|
|
|
|
bool sht3x_get_raw_data(sht3x_sensor_t* dev, sht3x_raw_data_t raw_data)
|
|
{
|
|
if (!dev || !dev->active || !raw_data) return false;
|
|
|
|
dev->error_code = SHT3x_OK;
|
|
|
|
if (sht3x_is_measuring (dev) == -1)
|
|
{
|
|
error_dev ("measurement is still running", __FUNCTION__, dev);
|
|
return false;
|
|
}
|
|
|
|
if (dev->mode == single_shot &&
|
|
sht3x_read_data(dev, raw_data, sizeof(sht3x_raw_data_t)))
|
|
{
|
|
debug_dev ("single shot data available", __FUNCTION__, dev);
|
|
dev->meas_started = false;
|
|
}
|
|
else if (dev->mode != single_shot &&
|
|
sht3x_send_command(dev, SHT3x_FETCH_DATA_CMD) &&
|
|
sht3x_read_data(dev, raw_data, sizeof(sht3x_raw_data_t)))
|
|
{
|
|
debug_dev ("periodic data available", __FUNCTION__, dev);
|
|
dev->meas_first = false;
|
|
}
|
|
else
|
|
{
|
|
error_dev ("read raw data failed", __FUNCTION__, dev);
|
|
dev->error_code |= SHT3x_READ_RAW_DATA_FAILED;
|
|
return false;
|
|
}
|
|
|
|
if (crc8(raw_data,2) != raw_data[2])
|
|
{
|
|
error_dev ("CRC check for temperature data failed", __FUNCTION__, dev);
|
|
dev->error_code |= SHT3x_WRONG_CRC_TEMPERATURE;
|
|
return false;
|
|
}
|
|
|
|
if (crc8(raw_data+3,2) != raw_data[5])
|
|
{
|
|
error_dev ("CRC check for humidity data failed", __FUNCTION__, dev);
|
|
dev->error_code |= SHT3x_WRONG_CRC_HUMIDITY;
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
bool sht3x_compute_values (sht3x_raw_data_t raw_data, sht3x_values_t* values)
|
|
{
|
|
if (!raw_data || !values) return false;
|
|
|
|
values->temperature = ((((raw_data[0] * 256.0) + raw_data[1]) * 175) / 65535.0) - 45;
|
|
values->humidity = ((((raw_data[3] * 256.0) + raw_data[4]) * 100) / 65535.0);
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
bool sht3x_get_results (sht3x_sensor_t* dev, sht3x_values_t* values)
|
|
{
|
|
if (!dev || !dev->active || !values) return false;
|
|
|
|
sht3x_raw_data_t raw_data;
|
|
|
|
if (!sht3x_get_raw_data (dev, raw_data))
|
|
return false;
|
|
|
|
return sht3x_compute_values (raw_data, values);
|
|
}
|
|
|
|
/* Functions for internal use only */
|
|
|
|
static bool sht3x_send_command(sht3x_sensor_t* dev, uint16_t cmd)
|
|
{
|
|
if (!dev || !dev->active) return false;
|
|
|
|
uint8_t data[2] = { cmd >> 8, cmd & 0xff };
|
|
|
|
debug_dev ("send command MSB=%02x LSB=%02x", __FUNCTION__, dev, data[0], data[1]);
|
|
|
|
int err;
|
|
int count = 10;
|
|
|
|
// in case i2c is busy, try to write up to ten times and 100 ms
|
|
// tested with a task that is disturbing by using i2c bus almost all the time
|
|
while ((err=i2c_slave_write(dev->bus, dev->addr, 0, data, 2)) == -EBUSY && count--)
|
|
vTaskDelay (10 / portTICK_PERIOD_MS);
|
|
|
|
if (err)
|
|
{
|
|
dev->error_code |= (err == -EBUSY) ? SHT3x_I2C_BUSY : SHT3x_I2C_SEND_CMD_FAILED;
|
|
error_dev ("i2c error %d on write command %02x", __FUNCTION__, dev, err, cmd);
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
static bool sht3x_read_data(sht3x_sensor_t* dev, uint8_t *data, uint32_t len)
|
|
{
|
|
if (!dev || !dev->active) return false;
|
|
|
|
int err;
|
|
int count = 10;
|
|
|
|
// in case i2c is busy, try to read up to ten times and 100 ms
|
|
while ((err=i2c_slave_read(dev->bus, dev->addr, 0, data, len)) == -EBUSY && count--)
|
|
vTaskDelay (10 / portTICK_PERIOD_MS);
|
|
|
|
if (err)
|
|
{
|
|
dev->error_code |= (err == -EBUSY) ? SHT3x_I2C_BUSY : SHT3x_I2C_READ_FAILED;
|
|
error_dev ("error %d on read %d byte", __FUNCTION__, dev, err, len);
|
|
return false;
|
|
}
|
|
|
|
# ifdef SHT3x_DEBUG
|
|
printf("SHT3x %s: bus %d, addr %02x - read following bytes: ",
|
|
__FUNCTION__, dev->bus, dev->addr);
|
|
for (int i=0; i < len; i++)
|
|
printf("%02x ", data[i]);
|
|
printf("\n");
|
|
# endif
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/*
|
|
static bool sht3x_reset (sht3x_sensor_t* dev)
|
|
{
|
|
if (!dev || !dev->active) return false;
|
|
|
|
debug_dev ("soft-reset triggered", __FUNCTION__, dev);
|
|
|
|
dev->error_code = SHT3x_OK;
|
|
|
|
// send reset command
|
|
if (!sht3x_send_command(dev, SHT3x_RESET_CMD))
|
|
{
|
|
dev->error_code |= SHT3x_SEND_RESET_CMD_FAILED;
|
|
return false;
|
|
}
|
|
// wait for small amount of time needed (according to datasheet 0.5ms)
|
|
vTaskDelay (20 / portTICK_PERIOD_MS);
|
|
|
|
uint16_t status;
|
|
|
|
// check the status after reset
|
|
if (!sht3x_get_status(dev, &status))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
*/
|
|
|
|
|
|
static bool sht3x_get_status (sht3x_sensor_t* dev, uint16_t* status)
|
|
{
|
|
if (!dev || !dev->active || !status) return false;
|
|
|
|
dev->error_code = SHT3x_OK;
|
|
|
|
uint8_t data[3];
|
|
|
|
if (!sht3x_send_command(dev, SHT3x_STATUS_CMD) || !sht3x_read_data(dev, data, 3))
|
|
{
|
|
dev->error_code |= SHT3x_STATUS_CMD_FAILED;
|
|
return false;
|
|
}
|
|
|
|
*status = data[0] << 8 | data[1];
|
|
debug_dev ("status=%02x", __FUNCTION__, dev, *status);
|
|
return true;
|
|
}
|
|
|
|
|
|
const uint8_t g_polynom = 0x31;
|
|
|
|
static uint8_t crc8 (uint8_t data[], int len)
|
|
{
|
|
// initialization value
|
|
uint8_t crc = 0xff;
|
|
|
|
// iterate over all bytes
|
|
for (int i=0; i < len; i++)
|
|
{
|
|
crc ^= data[i];
|
|
|
|
for (int i = 0; i < 8; i++)
|
|
{
|
|
bool xor = crc & 0x80;
|
|
crc = crc << 1;
|
|
crc = xor ? crc ^ g_polynom : crc;
|
|
}
|
|
}
|
|
|
|
return crc;
|
|
}
|
|
|
|
|