BMM150 not updating in forced mode

Hi all,
I'm trying to get BMM150 magnetometer data @100Hz using the BMI270 as master device, but when I configure the sensor in forced mode I only get the first measure, the next measures are all equals.

This is my configuration code for BMM150:

int8_t BMM150_DEVICE_Init() {
	int8_t rslt = BMM150_OK;

	// ----> BMM150 initialization over I2C (BMI270 aux)
	bmm150_dev.dev_id = BMM150_DEFAULT_I2C_ADDRESS;
	bmm150_dev.intf = BMM150_I2C_INTF;
	bmm150_dev.read = bmm150_read;
	bmm150_dev.write = bmm150_write;
	bmm150_dev.delay_ms = bmm150_delay_ms;

	rslt = bmm150_init(&bmm150_dev);
	if(rslt!=BMM150_OK) {
		goto exit;
	}
	// <---- BMM150 initialization over I2C (BMI270 aux)

	//perform_self_tests(&bmm150_dev);

	// ----> Configuration
	bmm150_dev.settings.preset_mode = BMM150_PRESETMODE_REGULAR;
	rslt = bmm150_set_presetmode(&bmm150_dev);
	if(rslt!=BMM150_OK) {
		goto exit;
	}

	bmm150_dev.settings.pwr_mode = BMM150_FORCED_MODE;
	rslt = bmm150_set_op_mode(&bmm150_dev);
	// <---- Configuration

	exit:
	if( rslt == BMM150_OK ) {
		systemStatus.bmm150_initialized = 1;
	} else {
		systemStatus.bmm150_initialized = 0;
	}
	return rslt;
}

void bmm150_delay_ms(uint32_t msec) {
	HAL_Delay(msec);
}

int8_t bmm150_read(uint8_t dev_id, uint8_t reg_addr, uint8_t *read_data, uint16_t len) {
	return bmi2_read_aux_man_mode(reg_addr, read_data, len, &bmi270_dev);
}

int8_t bmm150_write(uint8_t dev_id, uint8_t reg_addr, uint8_t *write_data, uint16_t len) {
	return bmi2_write_aux_man_mode(reg_addr, write_data, len, &bmi270_dev);
}

Is there something to be changed to get it working correctly?

Thank you,
Walter

Best reply by Myzhar

I finally found the solution to the problem: the BMM150 was correctly configured, but the BMI270 was not.
It is very important to set
config.cfg.aux.fcu_write_en = BMI2_ENABLE;
in the configuration of the auxiliar sensor, this option is really badly documented (no cited in BMM150 datasheet, no explained in BMI270 datasheet):

	// ----> Initialize BMM150
	struct bmi2_sens_config config;

	// Magnetometer in manual mode for configuration
	config.type = BMI2_AUX;
	config.cfg.aux.aux_en = BMI2_ENABLE;
	config.cfg.aux.manual_en = BMI2_TRUE;
	config.cfg.aux.i2c_device_addr = BMM150_DEFAULT_I2C_ADDRESS; // I2C address of BMM150
	config.cfg.aux.read_addr = BMM150_CHIP_ID_ADDR;	// Address of the first read address
	config.cfg.aux.man_rd_burst = BMI2_AUX_READ_LEN_0;	// Size of manual burst read

	// Set the configurations
	rslt = bmi2_set_sensor_config(&config, 1, &bmi270_dev);
	if (rslt != BMI2_OK)
		goto exit;

	rslt = BMM150_DEVICE_Init();
	if (rslt != 0)
		goto exit;

	// Automatic burst read
	config.type = BMI2_AUX;
	config.cfg.aux.aux_en = BMI2_ENABLE;
	config.cfg.aux.manual_en = BMI2_FALSE;
	config.cfg.aux.i2c_device_addr = BMM150_DEFAULT_I2C_ADDRESS; // I2C address of BMM150
	config.cfg.aux.read_addr = BMM150_DATA_X_LSB;	// Address of the first read address
	config.cfg.aux.offset = 0;
	config.cfg.aux.aux_rd_burst = BMI2_AUX_READ_LEN_3;	// Size of auto burst read
	config.cfg.aux.fcu_write_en = BMI2_ENABLE;
	config.cfg.aux.odr = BMI2_AUX_ODR_100HZ;

        // Set the configurations
	rslt = bmi2_set_sensor_config(&config, 1, &bmi270_dev);
	if (rslt != BMI2_OK)
		goto exit;
	// <---- Initialize BMM150

I suggest to add a configuration example for BMM150 in the BMI270 README.

Walter

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