Hello, I'm using the BMX055 in a company's project. I read the data using the bma2x2_driver, bmg160_driver and bmm150_sensor_api for ACC, GYRO and MAG respectively. The data coming from ACC and DATA seem to be fine, whereas the data from the MAG doesn't seem relyable. As a preliminary test I'm using the smartphone compass to detect the North, in order to compare it with the result I get from the BMX055. Since the results are very different and the readings from the BMX055 are varying over time I tried to perform a self test: - the normal test completes successfully - the advanced test always fails (I used 3 different boards) Here is a snipped of my code: static   struct   bmm150_dev   dev ;   s8  initMAG ( void ) {     s8 ret  =  BMM150_OK;      /* Sensor interface over I2C */      dev . dev_id   =  BMM150_DEFAULT_I2C_ADDRESS;      dev . intf   =  BMM150_I2C_INTF;      dev . read   =  user_i2c_read;      dev . write   =  user_i2c_write;      dev . delay_ms   =  user_delay_ms;          ret  =   bmm150_init ( & dev);      if (ret  !=   0 ) {          ESP_LOGE (TAG_IMU,  "Error initializing the magnetometer. Error code: %d" , ret);     }          ret  +=   perform_mag_self_tests ();      /* Setting the power mode as normal */      dev . settings . pwr_mode   =  BMM150_NORMAL_MODE;     ret  +=   bmm150_set_op_mode ( & dev);           /* Setting the preset mode as Low power mode      i.e. data rate = 10Hz XY-rep = 1 Z-rep = 2*/      dev . settings . preset_mode   =  BMM150_PRESETMODE_REGULAR;     ret  +=   bmm150_set_presetmode ( & dev);           return  ret;  }   where: int8_t   perform_mag_self_tests ( void ) {      int8_t  rslt;      /* Perform Normal Self test */     rslt  =   bmm150_perform_self_test (BMM150_NORMAL_SELF_TEST,  & dev);      ESP_LOGI (TAG_IMU,  "NORMAL SELF TEST RESULT :  %d" , rslt);           /* Validate normal self test result */      if  (rslt  ==  BMM150_OK) {          ESP_LOGI (TAG_IMU,  "Normal Self test passed" );     }  else  {          ESP_LOGE (TAG_IMU,  "Normal Self test failed" );     }      /* Perform Advanced Self test */     rslt  |=   bmm150_perform_self_test (BMM150_ADVANCED_SELF_TEST,  & dev);      ESP_LOGI (TAG_IMU,  "ADVANCED SELF TEST RESULT :  %d" , rslt);      /* Validate Advanced self test result */      if  (rslt  ==  BMM150_OK) {          ESP_LOGI (TAG_IMU,  "Advanced Self test passed" );     }  else  {          ESP_LOGE (TAG_IMU,  "Advanced Self test failed" );     }           return  rslt; }     Could you please help me identifying the problem?   Thank you! ... View more