# nrf54-arduino-core brings bare-metal Arduino support to Nordic nRF54L RISC-V MCUs

> **Key takeaway:** A new register-level Arduino core eliminates Zephyr and nRF Connect SDK dependencies for nRF54L development while exposing the VPR RISC-V coprocessor and experimental Thread/Matter/Zigbee stacks.

**Published:** 2026-10-27T18:09:13+00:00 
**Source:** Adafruit Electronics 
**Category:** open-hardware 
**Canonical URL:** https://fosswire.org/news/nrf54-arduino-core-brings-bare-metal-arduino-support-to-nord.html 

## Summary
Developer Lolren has released nrf54-arduino-core, an open-source Arduino core for Nordic Semiconductor's nRF54L family of wireless microcontrollers. Unlike Nordic's official tooling, this core communicates directly with hardware registers and requires no underlying Zephyr RTOS or separate nRF Connect SDK installation, reducing build complexity and firmware overhead. Supported hardware includes Seeed's XIAO nRF54L15 and XIAO nRF54LM20A, HOLYIOT modules, generic nRF54 modules, and Nordic's own nRF54L15 Development Kit.

The core implements standard Arduino APIs including pinMode, digitalWrite, analogRead, Wire, SPI, and Serial. For wireless connectivity, Bluetooth LE is the primary interface, served through a bundled Bluefruit52Lib compatibility layer that allows Adafruit-style sketches to port with minimal modifications rather than using ArduinoBLE. The implementation also exposes Nordic's VPR RISC-V coprocessor for auxiliary processing and handles board-specific power management, including nPM1300 PMIC integration and QSPI flash deep power-down on the LM20A variant. Installation is available through the Arduino IDE Boards Manager or PlatformIO, with the latter supporting GDB debugging and Unity framework testing since version 1.0.21. Thread, Matter, Zigbee, and Channel Sounding protocols are present for evaluation but explicitly marked experimental.

## Architecture and peripheral model
- **Bare-metal register access:** The core operates without Zephyr RTOS or nRF Connect SDK, talking directly to nRF54L hardware registers, which eliminates abstraction-layer overhead and external toolchain dependencies.
- **VPR RISC-V coprocessor exposure:** The implementation provides access to Nordic's VPR (Vector Processing RISC-V) coprocessor, allowing developers to offload computation from the main Cortex-M33 application core.
- **Board-specific power management:** Deep sleep handling includes nPM1300 PMIC control and QSPI flash deep power-down specifically for the XIAO nRF54LM20A, addressing battery-operated deployment scenarios.
- **Bluefruit52Lib BLE compatibility:** Bluetooth LE uses Adafruit's Bluefruit52Lib API rather than ArduinoBLE, providing a migration path for existing Adafruit nRF52 sketches with only minor modifications required.
- **Experimental 802.15.4 stacks:** Thread, Matter, Zigbee, and Channel Sounding are included for evaluation purposes but are explicitly excluded from the core's stable feature guarantee.

## Why it matters
This core fills a tooling gap for developers who want nRF54L hardware access without committing to Nordic's Zephyr-based ecosystem, offering a lower-barrier entry point for hobbyists and rapid prototyping workflows. The PlatformIO support with GDB debugging and Unity testing integration brings professional embedded development practices to the Arduino form factor. For open hardware vendors like Seeed and Adafruit, the Bluefruit52Lib compatibility layer protects existing sketch investments while the RISC-V coprocessor exposure prepares the community for heterogeneous compute patterns becoming standard in next-generation Nordic silicon.