STMicroelectronics LIS3DH 3-Axis Digital Accelerometer, ±2/4/8/16g, Low Power MEMS Sensor - I²C/SPI, LGA Package

Both interfaces provide digital acceleration data, but they differ in protocol and connection requirements. I²C uses two wires (SCL, SDA) and supports multiple devices on a single bus, making it simpler for basic setups. SPI uses four wires (SCK, MOSI, MISO, CS) and offers higher maximum data rates, which is beneficial for applications requiring faster sampling or lower latency. The interface is selected by configuring the device's SA0/CS pin.

The full-scale measurement range is software-configurable via the device's internal control registers. By writing specific values to the CTRL_REG4 register, you can select between ±2g, ±4g, ±8g, and ±16g. Choosing a smaller range (e.g., ±2g) provides higher sensitivity and resolution for subtle movements, while a larger range (e.g., ±16g) is necessary for detecting high-acceleration events like impacts or Sharp Microelectronics turns.

The integrated 32-level FIFO (First-In, First-Out) buffer stores acceleration data samples. This allows the host microcontroller to enter a low-power sleep mode while the sensor continues sampling, waking up only to batch-read data from the full buffer. This architecture significantly reduces overall system power consumption, which is critical for battery-operated IoT devices and wearables.

No, the LIS3DH is designed for a supply voltage (Vdd) between 1.71V and 3.6V. The I/O voltage (Vdd_IO) must be between 1.71V and Vdd + 0.1V. To interface with a 5V microcontroller, you must use a logic level converter or ensure the microcontroller's I/O pins are configured for 3.3V operation. Applying voltages above the absolute maximum rating can permanently damage the sensor.

These features are configured through the device's interrupt control registers (INT1_CFG, etc.). You can set thresholds and timing parameters for free-fall or tap events. When a configured event occurs, an interrupt pin (INT1 or INT2) is triggered, signaling the host processor without requiring constant polling of acceleration data. This offloads processing and allows for immediate, low-latency response to specific motion events.