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| # BMM150 sensor API | ||
| ## Introduction | ||
| This package contains the Bosch Sensortec's BMM150 Magnetometer sensor driver (sensor API) | ||
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| The sensor driver package includes bmm150.h, bmm150.c and bmm150_defs.h files | ||
| ### Sensor overview | ||
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| bmm150 sensor driver supports the following Bosch MEMS sensors | ||
| * BMM050 | ||
| * BMM150 | ||
| * BMC150 - Combination of bma2x2 + bmm150 APIs | ||
| * BMC056 - Combination of bma2x2 + bmm150 APIs | ||
| * BMX055 - Combination of bma2x2 + bmg160 + bmm150 APIs | ||
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| BMM150 is a standalone geomagnetic sensor for consumer market applications. | ||
| Performance and feature of BMM150 are carefully tuned and perfectly match the | ||
| demanding requirements of all 3-axis mobile applications such as electronic | ||
| compass, navigation or augmented reality. | ||
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| ## Integration details | ||
| * Integrate bmm150.h, bmm150_defs.h and bmm150.c file in to your project. | ||
| * Include the bmm150.h file in your code like below. | ||
| ``` c | ||
| #include "bmm150.h" | ||
| ``` | ||
| ### Target Application | ||
| - Magnetic heading information | ||
| - Tilt-compensated electronic compass | ||
| - Gyroscope calibration in 9-DoF application for mobile devices | ||
| - In-door navigation | ||
| - Gaming | ||
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| ## File information | ||
| * bmm150_defs.h : This header file has the constants, macros and datatype declarations. | ||
| * bmm150.h : This header file contains the declarations of the sensor driver APIs. | ||
| * bmm150.c : This source file contains the definitions of the sensor driver APIs. | ||
| ### Feature | ||
| - Magnetic field data | ||
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| ## Supported sensor interfaces | ||
| * SPI 4-wire | ||
| * I2C | ||
| ### Important links | ||
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| ## Usage guide | ||
| ### Initializing the sensor | ||
| To initialize the sensor, you will first need to create a device structure. You | ||
| can do this by creating an instance of the structure bmm150_dev. Then go on to | ||
| fill in the various parameters as shown below. | ||
| - [BMM150 product page](https://www.bosch-sensortec.com/products/motion-sensors/magnetometers-bmm150/) | ||
| - [BMM150 datasheet](https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bmm150-ds001.pdf) | ||
| - [BMM150 shuttle board flyer](https://www.bosch-sensortec.com/media/boschsensortec/downloads/shuttle_board_flyer/bst-dhw-fl016.pdf) | ||
| - [Community support page](https://community.bosch-sensortec.com) | ||
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| #### Example for SPI 4-Wire | ||
| ``` c | ||
| struct bmm150_dev dev; | ||
| int8_t rslt = BMM150_OK; | ||
| uint8_t dev_addr = 0; | ||
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| /* Sensor interface over SPI with native chip select line */ | ||
| dev.intf_ptr = &dev_addr; | ||
| dev.intf = BMM150_SPI_INTF; | ||
| dev.read = user_spi_read; | ||
| dev.write = user_spi_write; | ||
| dev.delay_us = user_delay_us; | ||
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| rslt = bmm150_init(&dev); | ||
| ``` | ||
| #### Example for I2C | ||
| ``` c | ||
| struct bmm150_dev dev; | ||
| int8_t rslt = BMM150_OK; | ||
| uint8_t dev_addr = BMM150_DEFAULT_I2C_ADDRESS; | ||
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| /* Sensor interface over I2C */ | ||
| dev.intf_ptr = &dev_addr; | ||
| dev.intf = BMM150_I2C_INTF; | ||
| dev.read = user_i2c_read; | ||
| dev.write = user_i2c_write; | ||
| dev.delay_us = user_delay_us; | ||
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| rslt = bmm150_init(&dev); | ||
| ``` | ||
| ### Sensor Configuration settings | ||
| #### Setting Normal operation mode (power mode) and preset mode. | ||
| ##### Example for configuring the sensor in normal power mode and Low power preset mode | ||
| ``` c | ||
| int8_t set_sensor_settings(struct bmm150_dev *dev) | ||
| { | ||
| int8_t rslt; | ||
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| /* Setting the power mode as normal */ | ||
| dev->settings.pwr_mode = BMM150_POWERMODE_NORMAL_MODE; | ||
| rslt = bmm150_set_op_mode(dev); | ||
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| /* 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_LOWPOWER; | ||
| rslt = bmm150_set_presetmode(dev); | ||
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| return rslt; | ||
| } | ||
| ``` | ||
| ### Reading sensor data | ||
| * Sensor data should be read after setting the desired power mode and preset mode. | ||
| #### Example for reading sensor data - Fixed point version | ||
| > Ensure that the macro "BMM150_USE_FLOATING_POINT" in the bmm150_defs.h file is commented out | ||
| ``` c | ||
| int8_t read_sensor_data(struct bmm150_dev *dev) | ||
| { | ||
| int8_t rslt; | ||
| /* Mag data for X,Y,Z axis are stored inside the | ||
| bmm150_dev structure in int16_t format */ | ||
| rslt = bmm150_read_mag_data(dev); | ||
| /* Print the Mag data */ | ||
| printf("\n Magnetometer data \n"); | ||
| printf("MAG X : %d \t MAG Y : %d \t MAG Z : %d \n" | ||
| ,dev->data.x, dev->data.y, dev->data.z); | ||
| return rslt; | ||
| } | ||
| ``` | ||
| #### Example for reading sensor data - Floating point version | ||
| > Enable the macro "BMM150_USE_FLOATING_POINT" in the bmm150_defs.h file (or) | ||
| > enable "BMM150_USE_FLOATING_POINT" in the compiler option of your project | ||
| ``` c | ||
| int8_t read_sensor_data(struct bmm150_dev *dev) | ||
| { | ||
| int8_t rslt; | ||
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| /* Mag data for X,Y,Z axis are stored inside the | ||
| bmm150_dev structure in float format */ | ||
| rslt = bmm150_read_mag_data(dev); | ||
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| /* Print the Mag data */ | ||
| printf("\n Magnetometer data \n"); | ||
| printf("MAG X : %0.2f \t MAG Y : %0.2f \t MAG Z : %0.2f \n" | ||
| ,dev->data.x, dev->data.y, dev->data.z); | ||
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| return rslt; | ||
| } | ||
| ``` | ||
| ### Self test - Normal self test and Advanced self test | ||
| #### Example for performing Normal self test and Advanced self test | ||
| ``` c | ||
| int8_t perform_self_tests(struct bmm150_dev *dev) | ||
| { | ||
| int8_t rslt; | ||
| /* Perform Normal Self test */ | ||
| rslt = bmm150_perform_self_test(BMM150_SELF_TEST_NORMAL, dev); | ||
| printf("\n NORMAL SELF TEST RESULT : %d",rslt); | ||
| /* Validate normal self test result */ | ||
| if (rslt == BMM150_OK) { | ||
| printf("\n Normal Self test passed "); | ||
| } else { | ||
| printf("\n Normal Self test failed "); | ||
| } | ||
| /* Perform Advanced Self test */ | ||
| rslt |= bmm150_perform_self_test(BMM150_SELF_TEST_ADVANCED, dev); | ||
| printf("\n ADVANCED SELF TEST RESULT : %d",rslt); | ||
| /* Validate Advanced self test result */ | ||
| if (rslt == BMM150_OK) { | ||
| printf("\n Advanced Self test passed "); | ||
| } else { | ||
| printf("\n Advanced Self test failed "); | ||
| } | ||
| return rslt; | ||
| } | ||
| ``` | ||
| ### Interrupt settings | ||
| #### Example for using Data ready interrupt to read data | ||
| > Configuring the interrupt | ||
| ``` c | ||
| int8_t drdy_interrupt_configure(struct bmm150_dev *dev) | ||
| { | ||
| int8_t rslt; | ||
| uint16_t desired_settings; | ||
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| /* Set the macros to enable DRDY pin */ | ||
| desired_settings = BMM150_SEL_DRDY_PIN_EN | BMM150_SEL_DRDY_POLARITY; | ||
| /* Set the drdy_pin_en to enable the drdy interrupt */ | ||
| dev->settings.int_settings.drdy_pin_en = BMM150_INT_ENABLE; | ||
| /* Set the polarity as active high on the DRDY pin */ | ||
| dev->settings.int_settings.drdy_polarity = BMM150_ACTIVE_HIGH_POLARITY; | ||
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| /* Set the configurations in the sensor */ | ||
| rslt = bmm150_set_sensor_settings(desired_settings, dev); | ||
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| return rslt; | ||
| } | ||
| ``` | ||
| > Read the interrupt status continuously to check for interrupt assertion (Polling method) | ||
| ``` c | ||
| int8_t drdy_interrupt_handling(struct bmm150_dev *dev) | ||
| { | ||
| int8_t rslt; | ||
| /* Read the interrupt status */ | ||
| rslt = bmm150_get_interrupt_status(dev); | ||
| if (rslt == BMM150_OK) { | ||
| if (dev->int_status & BMM150_INT_ASSERTED_DRDY) { | ||
| /* Interrupt asserted - Read mag data */ | ||
| rslt = bmm150_read_mag_data(dev); | ||
| printf("\n MAG DATA "); | ||
| printf("\n MAG X : %d MAG Y : %d MAG Z : %d " | ||
| ,dev->data.x,dev->data.y,dev->data.z); | ||
| } else { | ||
| /*Interrupt not asserted */ | ||
| printf("\n Data is not ready yet"); | ||
| } | ||
| } | ||
| return rslt; | ||
| } | ||
| --- | ||
| #### Copyright (C) 2020 Bosch Sensortec GmbH |