BME 680 configuration on PIC32

[Vilius]

Hello,

I am an undergraduate university student developing my thesis project with PIC32. I would like to use BME 680 sensor with it. I hooked everything on a breadboard, wrote a working I2C driver  for the PIC32, I also incorporated 3.3 <-> 1.8 V logic translator between the PIC32 and BME 680. But I got stuck with the configuration of the sensor... I was following these instructions: https://github.com/boschsensortec/BME680_driver

I have added both of the header files and the source file to my project, but still, I can not understand, how do I configure the sensor in the main program? The last section of the link that I provided gives a ,,Templates for function pointers" but I have already written the universal read and write functions for the I2C, so do I still have to write those again? (I though that the point of having a driver written for you is to avoid all those separate register reads and writes...) I may sound confusing, but I would really appreciate any help, explanations or observations. Could you give me an exact template for the main function, highlighting the variables or other parameters I have to change or write for myself? You could possibly save my project 🙂

For now, I came up with the example code, but I am not sure, if I have to write any more functions, or change the parameters...

    #include <xc.h> 
    #include "configurations_bits.h"                                                                  //Including microcontroller`s configuration settings
           
    #include <stddef.h>                                                                               //Including all the standard C libraries
    #include <stdint.h>                    
    #include <stdbool.h>                    
    #include <stdlib.h> 
    #include "stdio.h" 
    #include <sys/attribs.h> 
 
    #include "delay.h"                                                                                //Including all the separate module header files
    #include "inter_integrated_circuit_protocol.h" 
    #include "bme680.h" 

                                                                            
    //---EXAMPLE PART ONE-------------------------------------------------------------

    struct bme680_dev gas_sensor {

        gas_sensor.dev_id = BME680_I2C_ADDR_PRIMARY;                            //SDO pin is grounded, so this address is correct in my case
        gas_sensor.intf = BME680_I2C_INTF;
        gas_sensor.read = Inter_Integrated_Circuit_Read();                      //I2C read function is defined in the I2C header and source files
        gas_sensor.write = Inter_Integrated_Circuit_Write();                    //I2C write function is defined in the I2C header and source files
        gas_sensor.delay_ms = delay_ms();                                       //delay function is defined in the separate header and source files
                                                                                //SHOULD I ASSIGN THESE FUNCTIONS HERE?
        gas_sensor.amb_temp = 25;
    }

        int8_t rslt = BME680_OK;
        rslt = bme680_init(&gas_sensor);
        
        //---EXAMPLE PART ONE-------------------------------------------------------------
        
        
        
        int main(void) {                                                                              //Main program`s start
    
            Inter_Integrated_Circuit_Setup ();                                                        //Calling I2C configuration function
            Inter_Integrated_Circuit_Enable ();                                                       //Starting I2C module

           //---EXAMPLE PART TWO-------------------------------------------------------------
            
            uint8_t set_required_settings;

                /* Set the temperature, pressure and humidity settings */
                gas_sensor.tph_sett.os_hum = BME680_OS_2X;
                gas_sensor.tph_sett.os_pres = BME680_OS_4X;
                gas_sensor.tph_sett.os_temp = BME680_OS_8X;
                gas_sensor.tph_sett.filter = BME680_FILTER_SIZE_3;

                /* Set the remaining gas sensor settings and link the heating profile */
                gas_sensor.gas_sett.run_gas = BME680_ENABLE_GAS_MEAS;
                /* Create a ramp heat waveform in 3 steps */
                gas_sensor.gas_sett.heatr_temp = 320; /* degree Celsius */
                gas_sensor.gas_sett.heatr_dur = 150; /* milliseconds */

                /* Select the power mode */
                /* Must be set before writing the sensor configuration */
                gas_sensor.power_mode = BME680_FORCED_MODE; 

                /* Set the required sensor settings needed */
                set_required_settings = BME680_OST_SEL | BME680_OSP_SEL | BME680_OSH_SEL | BME680_FILTER_SEL 
                    | BME680_GAS_SENSOR_SEL;

                /* Set the desired sensor configuration */
                rslt = bme680_set_sensor_settings(set_required_settings,&gas_sensor);

                /* Set the power mode */
                rslt = bme680_set_sensor_mode(&gas_sensor);
      
            //---EXAMPLE PART TWO-------------------------------------------------------------
            
            
            //---EXAMPLE PART THREE-------------------------------------------------------------     
                
           uint16_t meas_period = 1000;    //Lets say 1000 millisecond? Is that the right value?
                bme680_get_profile_dur(&meas_period, &gas_sensor);

                struct bme680_field_data data;

                while (true){                                                                         //Main program loop
                   
                   delay_ms(meas_period); /* Delay till the measurement is ready */

                        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);
                        }
                        
            //---EXAMPLE PART THREE-------------------------------------------------------------     
                        
                        
                }
                
            return (EXIT_FAILURE);  
        }

[BSTRobin]

Hi Vilius,

You could refer BME68x driver code and example code from https://github.com/boschsensortec/BME68x-Sensor-API
You don't need to rewrite driver code as it has been provided in the form of API, you only need to modify common.c according your host platform.