STMicroelectronics EVALKITSTKNX

Overview

EVALKITSTKNX from STMicroelectronics is a KNX twisted-pair evaluation and development kit built around the STKNX miniature transceiver and STM32F103RBT6 microcontroller (Cortex-M3, 16 MHz, 128 kB Flash), supporting TP1-256 physical layer, EN 50491 compliance, and KAIstack protocol stack for building certified KNX devices in building automation.

For engineers reviewing the EVALKITSTKNX datasheet, EVALKITSTKNX pinout, EVALKITSTKNX application, or EVALKITSTKNX equivalent, this kit delivers full-stack KNX development capability-including isolated USB-JTAG/SWD debugging, Arduino/Morpho expansion compatibility, on-board RTC crystal option, SELV isolation mode, and pre-flashed test firmware-enabling rapid prototyping of sensors, actuators, and dimming systems compliant with CENELEC EN 50090, ISO/IEC 14543-3, and ANSI/ASHRAE 135.

Technical Context

The EVALKITSTKNX implements a complete KNX TP1-256 node architecture: the STM32F103RBT6 executes the TAPKO KAIstack protocol stack, interfaces with the STKNX transceiver via dedicated digital control lines and differential bus coupling, and supports both bus-powered and USB-powered "desktop mode" operation. Isolation barriers separate MCU logic from KNX bus domain, configurable via jumpers to meet SELV requirements per EN 61140.

Hardware features include dual debug paths (on-board ST-LINK/V2-1 with isolated USB UART + standard HE10 20-pin SWD/JTAG), four user buttons/LEDs for sensor/actuator emulation, one dedicated KNX programming button/LED, and optional 32.768 kHz crystal for RTC functionality-all integrated on a 2-layer reference layout for the STKNX analog front-end.

Key Specifications

Availability

EVALKITSTKNX is available at Aetrix Electronics and suitable for KNX device prototyping, building automation system integration, and certified product development requiring stable component supply, long-term design-in support, and traceable sourcing for industrial OEMs.

Supply support for EVALKITSTKNX 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, power management, and smart sensors for industrial, automotive, and IoT applications.

EVALKITSTKNX belongs to ST's Building Automation & Smart Home evaluation platform portfolio, engineered to accelerate development of EN 50090-compliant KNX devices using ST's transceiver and MCU ecosystem.

FAQ

What KNX protocol stack is pre-installed on EVALKITSTKNX?

The board ships with the TAPKO KAIstack KNX protocol stack, licensed and integrated by ST. It supports full TP1-256 messaging, object server functionality, and configuration via ETS software. A limited version is used in the LED dimming example; full stack licensing requires separate agreement with TAPKO.

Does EVALKITSTKNX support both bus-powered and USB-powered operation?

Yes - jumpers enable three power modes: KNX bus-only, USB-only ("desktop mode" for development without KNX infrastructure), or hybrid. In USB-only mode, the STKNX transceiver is disabled, isolating the bus domain while allowing full MCU firmware debug and integration.

Can I connect third-party expansion boards to EVALKITSTKNX?

Yes - the board provides Arduino Uno R3–compatible and ST Morpho pin headers, enabling direct use of STM32 Nucleo expansion boards (e.g., X-NUCLEO-LED16A1, X-NUCLEO-IKS01A3) without adapters or level-shifting circuitry.

Is hardware isolation between MCU and KNX bus configurable?

Yes - isolation is implemented using digital isolators between the STM32 and STKNX. By default, isolators are bypassed; installing provided jumpers activates them, enabling SELV-compliant development per EN 61140 for safety-critical installations.