STMicroelectronics STEVAL-MKI124V1

Overview

STEVAL-MKI124V1 from STMicroelectronics is an adapter evaluation board supporting simultaneous interface and prototyping of three MEMS sensors - L3GD20 (3-axis gyroscope), LSM303DLHC (3-axis accelerometer + 3-axis magnetometer), and LPS331AP (digital barometric pressure sensor) - via a standard DIL24 socket. It includes on-board decoupling capacitors, pull-up resistors, and full pin access for I²C communication, interrupt signaling, and power domains.

For engineers reviewing the STEVAL-MKI124V1 datasheet, STEVAL-MKI124V1 pinout, STEVAL-MKI124V1 application, or STEVAL-MKI124V1 equivalent, this board enables rapid validation of 10-axis sensor fusion in motion-tracking, orientation-aware embedded systems, and environmental sensing applications without custom PCB design.

Technical Context

The board implements direct pin mapping from all three ICs to a single 24-pin DIL header, preserving native I²C addressability and interrupt routing (INT1/INT2 per device). Each sensor's VDD and Vdd_IO rails are independently routed with dedicated 10 µF and 100 nF decoupling.

It is mechanically and electrically designed for plug-in compatibility with the STEVAL-MKI109V2 motherboard, which provides USB-to-I²C bridging via an STM32F103 microcontroller and supports Unico GUI-based configuration and real-time data streaming.

Key Specifications

Availability

STEVAL-MKI124V1 is available at Aetrix Electronics and suitable for motion-sensing reference designs, sensor fusion algorithm development, and industrial IoT edge node prototyping requiring stable component supply and quick-turn evaluation capability.

Supply support for STEVAL-MKI124V1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing microcontrollers, sensors, power ICs, and analog/mixed-signal devices for industrial, automotive, and consumer markets.

This board belongs to ST's STEVAL (ST Evaluation) series - purpose-built adapter and demonstration platforms that simplify integration of ST's MEMS and sensor products into customer systems using standardized mechanical and electrical interfaces.

FAQ

Does STEVAL-MKI124V1 support SPI communication with the onboard sensors?

No. The board routes only I²C signals (SDA/SCL) and interrupt lines for all three sensors. The L3GD20 and LSM303DLHC support SPI in their native IC form, but STEVAL-MKI124V1 does not expose SPI pins - it is strictly an I²C-optimized adapter. No CS or SDO/SDI traces are brought out to the DIL24 header beyond what's required for I²C addressing.

Can STEVAL-MKI124V1 be used without the STEVAL-MKI109V2 motherboard?

Yes. The DIL24 footprint allows direct connection to any host system providing 3.3 V power, I²C pull-ups, and compatible logic levels. However, standalone use requires external firmware to manage multi-device I²C arbitration, register mapping, and interrupt handling - unlike the STEVAL-MKI109V2, which includes preloaded STM32 firmware and Unico GUI support.

What is the function of the "Res" pins labeled on U2 (L3GD20) and U3 (LPS331AP)?

Those are reserved pins per the respective IC datasheets: L3GD20 pins 9–12 and LPS331AP pins 9–13 are marked "Res" (Reserved) and must be left unconnected. They have no internal connection or defined function and are not tied to ground or VDD on the board - confirmed by schematic inspection and ST's official documentation.

Are the LSM303DLHC magnetometer and accelerometer on separate I²C addresses?

Yes. The LSM303DLHC integrates both functions but exposes them on two distinct I²C addresses: 0x1E (default) for the magnetometer and 0x18 (default) for the accelerometer. STEVAL-MKI124V1 preserves this separation, allowing independent initialization and readout without address conflict or internal arbitration.