STMicroelectronics STEVAL-FKI868V1

Overview

STEVAL-FKI868V1 from STMicroelectronics is a sub-1 GHz transceiver development kit built around the S2-LP ultra-low-power narrowband RF transceiver and STM32L152RE Nucleo board, operating in 860–940 MHz ISM bands with +16 dBm programmable output power, -130 dBm receiver sensitivity, and support for 2-FSK/4-GFSK/OOK modulation at data rates up to 500 kbps - deployed in Wireless M-Bus smart metering endpoints.

For engineers reviewing the STEVAL-FKI868V1 datasheet, STEVAL-FKI868V1 pinout, STEVAL-FKI868V1 application, or STEVAL-FKI868V1 equivalent, this kit enables rapid prototyping of low-power, long-range sub-GHz wireless systems requiring SPI-controlled RF configuration, automatic ACK/retransmission protocol handling, USB-based firmware update, and RoHS-compliant hardware integration.

Technical Context

The kit integrates the S2-LP transceiver (QFN32 package) with an STM32L152RE MCU (LQFP64), forming a complete evaluation platform where the MCU executes S2-LP firmware via SPI, manages low-duty-cycle RX/TX operation, and hosts GUI-driven configuration over USB. The S2-LP implements a fully integrated fractional-N PLL with VCO, analog front-end with differential RX path, and digital baseband supporting packet filtering, CRC, and automatic packet acknowledgment.

Hardware-level RF tuning targets the 860–940 MHz band using discrete matching components (L6, L7, C4, C8, C11, C14, C19, C29, C33) and a 32 MHz crystal (Y1); power management includes SMPS regulation (U2 pins 1–2) and separate analog/digital supply domains (VDDANASYNT, VDDR_DIG, VDDSMP).

Key Specifications

Availability

STEVAL-FKI868V1 is available at Aetrix Electronics and suitable for smart utility metering, industrial sensor telemetry, battery-powered IoT gateways, and Wireless M-Bus endpoint validation requiring stable component supply and full-stack RF+MCU evaluation capability.

Supply support for STEVAL-FKI868V1 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, analog ICs, MEMS, and power devices for industrial, automotive, and consumer applications.

This kit belongs to ST's STEVAL evaluation platform family, engineered to accelerate time-to-prototype for sub-GHz RF system developers targeting regulatory-compliant, ultra-low-power wireless communication in utility infrastructure and industrial monitoring.

FAQ

Does STEVAL-FKI868V1 support Wireless M-Bus Mode T out of the box?

Yes - the included firmware and GUI implement full Wireless M-Bus Mode T (169 MHz variant adapted to 868 MHz band), including WMBus frame structure, encryption (AES-128), and master/slave timing synchronization per EN 13757-4. No firmware modification is required to operate in certified Mode T configuration.

Can the S2-LP transceiver on this board be used independently of the STM32L152RE MCU?

Yes - the S2-LP (U2) exposes all critical control pins (SDN, CSN, SDI, SDO, SCLK, GPIO0–GPIO3) on accessible headers (CN1, CN2, CN3, CN4). Users may disconnect the STM32L152RE and drive the transceiver directly via external microcontroller or logic analyzer using standard SPI timing and register map documented in S2-LP datasheet (DocID027972).

What antenna options are validated for STEVAL-FKI868V1?

The board includes a U.FL connector (J1) and matching network optimized for 50 Ω 868 MHz monopole or PCB trace antennas. ST validates performance with Johanson 2450AT18A100E (868 MHz chip antenna) and custom ¼-wave PCB traces - radiated output power remains within ±0.5 dB of +16 dBm specification when using these antennas with proper ground plane layout.

Is USB interface used only for programming or also for real-time RF packet capture?

The USB interface operates as a virtual COM port (CDC class) and carries both firmware updates and bidirectional packet traffic: the GUI sends configuration commands and TX payloads over USB, while received packets - including RSSI, LQI, timestamp, and raw payload - are streamed back in real time with <50 ms latency, enabling live spectrum and protocol analysis without additional sniffing hardware.