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Reformatted the README and fixed bug in documentation for reading out sensor data

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README.md
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@ -1,74 +1,85 @@
# BME680 sensor API # BME680 sensor API
## Introduction ## Introduction
This package contains the Bosch Sensortec's BME680 gas sensor API This package contains the Bosch Sensortec's BME680 gas sensor API
The sensor driver package includes bme680.h, bme680.c and bme680_defs.h files The sensor driver package includes bme680.h, bme680.c and bme680_defs.h files
## Version ## Version
File | Version | Date File | Version | Date
--------------|---------|------------- --------------|---------|-------------
bme680.c | 3.5.8 | 22 Feb 2018 bme680.c | 3.5.8 | 22 Feb 2018
bme680.h | 3.5.8 | 22 Feb 2018 bme680.h | 3.5.8 | 22 Feb 2018
bme680_defs.h | 3.5.8 | 22 Feb 2018 bme680_defs.h | 3.5.8 | 22 Feb 2018
## Integration details ## Integration details
* Integrate bme680.h, bme680_defs.h and bme680.c file in to your project. * Integrate bme680.h, bme680_defs.h and bme680.c file in to your project.
* Include the bme680.h file in your code like below. * Include the bme680.h file in your code like below.
``` c ``` c
#include "bme680.h" #include "bme680.h"
``` ```
## File information ## File information
* bme680_defs.h : This header file has the constants, macros and datatype declarations. * bme680_defs.h : This header file has the constants, macros and datatype declarations.
* bme680.h : This header file contains the declarations of the sensor driver APIs. * bme680.h : This header file contains the declarations of the sensor driver APIs.
* bme680.c : This source file contains the definitions of the sensor driver APIs. * bme680.c : This source file contains the definitions of the sensor driver APIs.
## Supported sensor interfaces ## Supported sensor interfaces
* SPI 4-wire * SPI 4-wire
* I2C * I2C
## Usage guide ## Usage guide
### Initializing the sensor ### Initializing the sensor
To initialize the sensor, you will first need to create a device structure. You To initialize the sensor, you will first need to create a device structure. You
can do this by creating an instance of the structure bme680_dev. Then go on to can do this by creating an instance of the structure bme680_dev. Then go on to
fill in the various parameters as shown below fill in the various parameters as shown below
#### Example for SPI 4-Wire #### Example for SPI 4-Wire
``` c
struct bme680_dev gas_sensor;
/* You may assign a chip select identifier to be handled later */ ``` c
gas_sensor.dev_id = 0; struct bme680_dev gas_sensor;
gas_sensor.intf = BME680_SPI_INTF;
gas_sensor.read = user_spi_read; /* You may assign a chip select identifier to be handled later */
gas_sensor.write = user_spi_write; gas_sensor.dev_id = 0;
gas_sensor.delay_ms = user_delay_ms; gas_sensor.intf = BME680_SPI_INTF;
gas_sensor.read = user_spi_read;
gas_sensor.write = user_spi_write;
gas_sensor.delay_ms = user_delay_ms;
/* amb_temp can be set to 25 prior to configuring the gas sensor /* amb_temp can be set to 25 prior to configuring the gas sensor
* or by performing a few temperature readings without operating the gas sensor. * or by performing a few temperature readings without operating the gas sensor.
*/ */
gas_sensor.amb_temp = 25; gas_sensor.amb_temp = 25;
int8_t rslt = BME680_OK; int8_t rslt = BME680_OK;
rslt = bme680_init(&gas_sensor); rslt = bme680_init(&gas_sensor);
``` ```
#### Example for I2C #### Example for I2C
``` c
struct bme680_dev gas_sensor;
gas_sensor.dev_id = BME680_I2C_ADDR_PRIMARY; ``` c
gas_sensor.intf = BME680_I2C_INTF; struct bme680_dev gas_sensor;
gas_sensor.read = user_i2c_read;
gas_sensor.write = user_i2c_write; gas_sensor.dev_id = BME680_I2C_ADDR_PRIMARY;
gas_sensor.delay_ms = user_delay_ms; gas_sensor.intf = BME680_I2C_INTF;
gas_sensor.read = user_i2c_read;
gas_sensor.write = user_i2c_write;
gas_sensor.delay_ms = user_delay_ms;
/* amb_temp can be set to 25 prior to configuring the gas sensor /* amb_temp can be set to 25 prior to configuring the gas sensor
* or by performing a few temperature readings without operating the gas sensor. * or by performing a few temperature readings without operating the gas sensor.
*/ */
gas_sensor.amb_temp = 25; gas_sensor.amb_temp = 25;
int8_t rslt = BME680_OK; int8_t rslt = BME680_OK;
rslt = bme680_init(&gas_sensor); rslt = bme680_init(&gas_sensor);
``` ```
Regarding compensation functions for temperature, pressure, humidity and gas we have two implementations. Regarding compensation functions for temperature, pressure, humidity and gas we have two implementations.
@ -82,63 +93,76 @@ If the user needs the floating point version, the user has to un-comment BME680_
in bme680_defs.h file or to add it in the compiler flags. in bme680_defs.h file or to add it in the compiler flags.
### Configuring the sensor ### Configuring the sensor
#### Example for configuring the sensor in forced mode #### Example for configuring the sensor in forced mode
``` c ``` c
uint8_t set_required_settings; uint8_t set_required_settings;
/* Set the temperature, pressure and humidity settings */ /* Set the temperature, pressure and humidity settings */
gas_sensor.tph_sett.os_hum = BME680_OS_2X; gas_sensor.tph_sett.os_hum = BME680_OS_2X;
gas_sensor.tph_sett.os_pres = BME680_OS_4X; gas_sensor.tph_sett.os_pres = BME680_OS_4X;
gas_sensor.tph_sett.os_temp = BME680_OS_8X; gas_sensor.tph_sett.os_temp = BME680_OS_8X;
gas_sensor.tph_sett.filter = BME680_FILTER_SIZE_3; gas_sensor.tph_sett.filter = BME680_FILTER_SIZE_3;
/* Set the remaining gas sensor settings and link the heating profile */ /* Set the remaining gas sensor settings and link the heating profile */
gas_sensor.gas_sett.run_gas = BME680_ENABLE_GAS_MEAS; gas_sensor.gas_sett.run_gas = BME680_ENABLE_GAS_MEAS;
/* Create a ramp heat waveform in 3 steps */ /* Create a ramp heat waveform in 3 steps */
gas_sensor.gas_sett.heatr_temp = 320; /* degree Celsius */ gas_sensor.gas_sett.heatr_temp = 320; /* degree Celsius */
gas_sensor.gas_sett.heatr_dur = 150; /* milliseconds */ gas_sensor.gas_sett.heatr_dur = 150; /* milliseconds */
/* Select the power mode */ /* Select the power mode */
/* Must be set before writing the sensor configuration */ /* Must be set before writing the sensor configuration */
gas_sensor.power_mode = BME680_FORCED_MODE; gas_sensor.power_mode = BME680_FORCED_MODE;
/* Set the required sensor settings needed */ /* Set the required sensor settings needed */
set_required_settings = BME680_OST_SEL | BME680_OSP_SEL | BME680_OSH_SEL | BME680_FILTER_SEL set_required_settings = BME680_OST_SEL | BME680_OSP_SEL | BME680_OSH_SEL | BME680_FILTER_SEL
| BME680_GAS_SENSOR_SEL; | BME680_GAS_SENSOR_SEL;
/* Set the desired sensor configuration */ /* Set the desired sensor configuration */
rslt = bme680_set_sensor_settings(set_required_settings,&gas_sensor); rslt = bme680_set_sensor_settings(set_required_settings,&gas_sensor);
/* Set the power mode */
rslt = bme680_set_sensor_mode(&gas_sensor);
/* Set the power mode */
rslt = bme680_set_sensor_mode(&gas_sensor);
/* Get the total measurement duration so as to sleep or wait till the
* measurement is complete */
uint16_t meas_period;
bme680_get_profile_dur(&meas_period, &gas_sensor);
user_delay_ms(meas_period); /* Delay till the measurement is ready */
``` ```
### Reading sensor data ### Reading sensor data
#### Example for reading all sensor data #### Example for reading all sensor data
``` c ``` c
struct bme680_field_data data; /* Get the total measurement duration so as to sleep or wait till the
* measurement is complete */
uint16_t meas_period;
bme680_get_profile_dur(&meas_period, &gas_sensor);
while(1) struct bme680_field_data data;
{
rslt = bme680_get_sensor_data(&data, &gas_sensor);
printf("T: %.2f degC, P: %.2f hPa, H %.2f %%rH ", data.temperature / 100.0f, while(1)
data.pressure / 100.0f, data.humidity / 1000.0f ); {
/* Avoid using measurements from an unstable heating setup */ user_delay_ms(meas_period); /* Delay till the measurement is ready */
if(data.status & BME680_GASM_VALID_MSK)
printf(", G: %d ohms", data.gas_resistance);
printf("\r\n"); rslt = bme680_get_sensor_data(&data, &gas_sensor);
}
printf("T: %.2f degC, P: %.2f hPa, H %.2f %%rH ", data.temperature / 100.0f,
data.pressure / 100.0f, data.humidity / 1000.0f );
/* Avoid using measurements from an unstable heating setup */
if(data.status & BME680_GASM_VALID_MSK)
printf(", G: %d ohms", data.gas_resistance);
printf("\r\n");
/* Trigger the next measurement if you would like to read data out continuously */
if (gas_sensor.power_mode == BME680_FORCED_MODE) {
rslt = bme680_set_sensor_mode(&gas_sensor);
}
}
``` ```
### Templates for function pointers ### Templates for function pointers
``` c ``` c
void user_delay_ms(uint32_t period) void user_delay_ms(uint32_t period)