Capture motion data in three dimensions with BMA456 and STM32F302VC

Accel 11 Click is based on the BMA456, a digital triaxial acceleration sensor from Bosch Sensortec. This sensor has many features ideally suited for wearables, handheld, and IoT applications, offering a good balance between the performance and the power consumption. One of its key features is its extremely low power consumption, which makes it perfectly suited for such applications. There are several power modes that the BMA456 device can use. While in Low Power mode, the device consumes the least power, but access to some features is restricted. More information can be found within the BMA456 datasheet. The BMA456 sensor can measure acceleration within ranges of ±2 g, ±4 g, ±8, and ±16 g. It can output the measurement data using the Output Data Rate (ODR) from 0.78Hz (Low Power mode) up to 1600Hz (Performance mode). A high-precision analog front end facilitates highly sensitive MEMS, featuring a 16-bit A/D Converter. It allows very high output accuracy, even during low amplitude changes. This makes the sensor particularly sensitive and accurate with movements that

generate relatively low acceleration signals. However, using a highly sensitive MEMS makes the BMA456 prone to damage caused by extremely high g-forces (10,000g for less than 200µs). Acceleration data is available in 16-bit format from the data registers and the internal FIFO buffer of 1kb. The FIFO buffer can be used for more complex calculations or timed readings, reducing the traffic on the communication interface. The interrupt engine facilitates the FIFO buffer, triggering an interrupt for two FIFO events: the watermark event and the FIFO buffer full event. FIFO buffer allows optimization within the firmware that runs on the host MCU. Besides the acceleration MEMS and complementary analog front-end circuit, the BMA456 sensor has an integrated temperature sensor. It is updated every 1.2s and sampled to an 8-bit value (complement of 2’s format). Interrupts can be triggered for many different events. Some basic events include the data-ready interrupt event and aforementioned FIFO events, while so-called feature engines can trigger an interrupt for any of the detected

motion/movement events, including step detection/counter, activity recognition, tilt on the wrist, tap/double tap, any/no motion, and error event interrupt. The extensive interrupt engine can use two programmable interrupt pins. Depending on settings in appropriate registers, these pins can be assigned with any interrupt source and can be either LOW or HIGH on interrupt. These two pins are routed to the INT and AN pin of the mikroBUS™ and are labeled IT1 and IT2, respectively. Accel 11 click offers two communication interfaces. It can be used with either I2C or SPI. The onboard SMD jumpers labeled COMM SEL allow switching between the two interfaces. Note that all the jumpers must be positioned in the I2C or SPI position. When the I2C interface is selected, an additional SMD jumper labeled ADDR SEL becomes available, determining the least significant bit of the BMA456 I2C address. The Click board™ should be interfaced only with MCUs that use logic levels of 3.3V.

Fusion for STM32 v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different 32-bit ARM® Cortex®-M based MCUs from STMicroelectronics, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, Fusion for STM32 v8 provides a fluid and immersive working experience, allowing

access anywhere and under any circumstances at any time. Each part of the Fusion for STM32 v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for STM32 v8 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.