Achieve distance and angular measurements for position determination in 3D environments with AK09970N and STM32F091RC

3D Hall 7 Click is based on the AK09970N, a low power 3D magnetic sensor from AKM Semiconductor. This sensor relies on a Hall effect to accurately sense magnetic field changes on three perpendicular axes. The internal magnetic field sensing elements are multiplexed and connected to a pre-amplifier and then to a 16-bit low noise Analog to Digital Converter (ADC), which sequentially samples each sensor, providing 16-bit spatial data over the digital interface. The magnetic sensor has a very low pin count. Therefore, SPI and I2C lines are multiplexed on the same pins. In order to allow functionality for both SPI and I2C interfaces, 3D Hall 7 click have onboard jumpers for communication interface selection. Thus, the communication interface selection procedure relies on switching the appropriate SMD jumpers, named COMM SEL. Note that all of the I2C/SPI group jumpers need to be switched at the same side: all three should either be soldered as I2C or SPI. If one of them shows in the opposite position from the rest, the communication with the IC might not be possible. The power consumption is a big concern as of lately, with the introduction of the IoT. The ability to work in a low power mode is a must for every device which is to be used for any type of IoT

networking. The AK09970N magnetic sensor features power down mode, single measurement mode and seven continuous measurement modes, allowing the user to make a perfect balance between sampling frequency, measurement accuracy and power consumption. The power consumption is in a close relationship with the data output refresh rate (ODR). The AK09970N magnetic sensor also features a powerful programmable interrupt engine, which allows many event sources to be signaled via the two interrupt pins (INT and ODINT), which are routed from the sensor to the mikroBUS™ INT and AN pins respectively. A very useful function of the interrupt engine is the signaling of the data ready event. That way, the host MCU does not have to poll the sensor for the data acquisition. The sensor can simply trigger an interrupt when the data is ready for reading. The interrupt engine allows some other customizations of the interrupt signal, such as the magnetic sensor overflow, ADC overflow and Switch event. The sensor provides raw data output, based on a strength of the magnetic field. The measurement is affected by many factors: slight manufacturing differences between ICs affect the readings, even the slight differences between Hall plates within the same IC

might affect the accuracy, although the IC contains highly matched sensing elements. Also, the altitude might affect the readings, as well as temperature changes. Therefore, the IC is equipped with the temperature independent reference voltage, thus minimizing the influence the mentioned unwanted factors. The power mode, output data rate, interrupt thresholds for each axis, and other working parameters, including the availability of the I2C interface, are contained within the configuration registers of the AK09970N magnetic sensor. The sensor is highly configurable, with many configuration options. The AK09970N datasheet contains an in-depth explanation of all the registers and their functionality. However, 3D Hall 7 software library contains simplified functions that allow straight-forward readings to be performed, reducing the steps needed for a proper initialization and configuration of the device. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

Nucleo-64 with STM32F091RC MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin

headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is

provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.