How to Connect ST’s X-NUCLEO-IKS4A1 Expansion Board with Sensors via I2C to Facilitate IoT Development?

ArticleOverview

In this article, DigiKey introduces how ST’s X-NUCLEO-IKS4A1 expansion board connects various sensors through the standard I²C bus and hierarchical bus architecture, facilitating the development of complex IoT applications.

How does STMicroelectronics’ X-NUCLEO-IKS4A1 expansion board connect various sensors via I2C?

STMicroelectronics has launched the expansion board X-NUCLEO-IKS4A1, which is a motion MEMS and environmental sensor evaluation board kit. This expansion board supports testing the functionality of motion MEMS accelerometers, gyroscopes, magnetometers, as well as environmental humidity, temperature, and pressure sensors through theI²C bus.

The X-NUCLEO-IKS4A1 expansion board can connect sensors in two ways via the I²C mode:

• Standard I²C bus connection

• Hierarchical bus architecture

X-NUCLEO-IKS4A1 expansion board

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1.Standard I²C bus connection

• Connection Logic: All sensors (including inertial and environmental sensors) are connected to the external STM32 Nucleo board via the same I²C bus (uC_I²C).

• Pin Configuration:

• J4:1-2、11-12 pins define STM_SDA = SENS_SDA (data pin),HUB_SDx = GND (hub data pin grounded).

• J5:1-2、11-12 pins define STM_SCL = SENS_SCL (clock pin),HUB_SCx = GND (hub clock pin grounded).

• Applicable Scenarios: Simple sensor data collection, all devices share the main I²C bus without complex bus management.

2. Hierarchical Bus Architecture

• For example, usingLSM6DSO16IS asI²C sensor hub:

• Main Bus (uC_I²C): Directly connects LSM6DSV16X (6 axis IMU),LIS2DUXS12 (3 axis accelerometer),SHT40AD1B (temperature and humidity sensor), communicating with the STM32 Nucleo board’s MCU to transmit core inertial / temperature and humidity data.

• Auxiliary Bus (SENS_I²C): Controlled by LSM6DSO16IS (sensor hub) to connect LPS22DF (pressure),LIS2MDL (magnetometer),STTS22H (temperature) and DIL24 socket (to expand external sensors like infrared sensors), achieving power supply and environmental data collection for 6 axis IMU functionality.

• Pin Configuration:

• J4:7-8 pins define HUB2_SDx = SENS_SDA (auxiliary bus data pin).

• J5:7-8 pins define HUB2_SCx = SENS_SCL (auxiliary bus clock pin).

• Features: Hierarchical management through the hub enhances multi-sensor data processing efficiency, supports expansion of external sensors, suitable for complex IoT / environmental monitoring applications (such as simultaneous collection of inertial, temperature and humidity, pressure, and magnetic field data).

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