nRF54L Arduino Framework (s145 SoftDevice)

Arduino BSP for Nordic Semiconductor nRF54L05 / nRF54L10 / nRF54L15 with the s145 SoftDevice 9.0.0. Derived from Adafruit_nRF52_Arduino and reworked for nRF54L peripherals.

PlatformIO only. This framework is consumed exclusively through the companion PlatformIO platform caveman99/platform-nordicnrf54. There is no platform.txt, boards.txt, or Arduino IDE / Board Manager support, and there are no plans to add any. Use PlatformIO.

Supported boards

Variant	MCU	Source
xiao_nrf54l15	nRF54L15	Seeed Studio XIAO nRF54L15
xiao_nrf54l15_sense	nRF54L15	Seeed Studio XIAO nRF54L15 Sense
nrf54l15dk	nRF54L15	Nordic nRF54L15-DK
nrf54l10dk	nRF54L10	Nordic nRF54L15-DK with L10 silicon
nrf54l05dk	nRF54L05	Nordic nRF54L15-DK with L05 silicon

Board JSONs and upload tooling live in the PlatformIO platform repo.

Installation

; platformio.ini
[env:xiao_nrf54l15]
platform = https://github.com/caveman99/platform-nordicnrf54.git
framework = arduino
board = xiao_nrf54l15

The platform pulls this framework, the nRF54_Bootloader hex package, and toolchains automatically on first build.

What's in here

• s145 SoftDevice 9.0.0 API headers and merge-time hex (cores/nRF5/nordic/softdevice/s145_nrf54l_9.0.0_API/, bootloader/s145/9.0.0/*_softdevice.hex)
• nRF54L MDK headers for L05/L10/L15 application + flpr targets (cores/nRF5/nordic/nrfx/mdk/)
• FreeRTOS port running off the GRTC peripheral (nRF54L has no SysTick); see cores/nRF5/freertos/portable/GCC/nrf54l/
• Linker scripts for all three chips that reserve 28 KB at the top of the application FLASH region for InternalFS (cores/nRF5/linker/)
• nrf54l_compat.h force-included by the platform's build script. Aliases nRF52 peripheral names to their nRF54L equivalents (NRF_PWM0..2 → NRF_PWM20..22, NRF_TWIM0/1 → NRF_TWIM20/22, NRF_SPIM0/2 → NRF_SPIM00/21, NRF_UARTE0/1 → NRF_UARTE00/20, NRF_GPIOTE → NRF_GPIOTE20, etc.) so most of the Adafruit core code compiles unmodified
• wiring_analog_nRF54L.c — dedicated SAADC implementation for nRF54L (different reference voltage, multiplier gains, microsecond TACQ, byte-count MAXCNT, structured PSELP)
• InternalFileSystem (LittleFS) wired against __flash_arduino_start / __bootloader_addr linker symbols, so no per-chip ifdefs in C++ code
• Bluefruit54Lib with HID detached from TinyUSB, plus BANDWIDTH-aware data-length-update reply
• Library wrappers for SPI, Wire (with per-variant TWIM instance override), Servo, SoftwareSerial, RotaryEncoder, PDM, nRF54Crypto (CRACEN-backed replacement for nRF52840's CryptoCell)

Memory map

Chip	App FLASH	InternalFS (LittleFS)	Bootloader
nRF54L05	0x01000 – 0x47000 (~280 KB)	0x47000 – 0x4E000 (28 KB)	0x50000
nRF54L10	0x01000 – 0xC7000 (~792 KB)	0xC7000 – 0xCE000 (28 KB)	0xD0000
nRF54L15	0x01000 – 0x147000 (~1.27 MB)	0x147000 – 0x14E000 (28 KB)	0x150000

Bootloader addresses confirmed against caveman99/nRF54_Bootloader linker scripts. The 8 KB gap between InternalFS end and bootloader start is consistent across all three chips.

Limitations

• No USB. nRF54L has no USB peripheral. The Adafruit_TinyUSB_Arduino submodule has been removed. Sketches that need a host serial channel on the XIAO variants get it through the on-board SAMD11 USB bridge over UART, not over native CDC.
• No Adafruit_nRFCrypto. nRF52840's CryptoCell CC310 is replaced by CRACEN on nRF54L. Use nRF54Crypto/ instead.
• HardwarePWM and Wire share peripheral fabric on XIAO. On the XIAO variants, Wire is routed to TWIM22 (a dedicated TWI controller) via a per-variant override so it doesn't compete with SPI/UARTE on the SERIAL00/SERIAL20 fabric. See variants/xiao_nrf54l15/variant.h.
• Bluefruit BLE features that depend on CC310 (LESC) are not yet reimplemented against CRACEN. Legacy SMP pairing works.

Credits

• Adafruit_nRF52_Arduino — the codebase this fork descends from. Core class layout, Bluefruit54Lib, Wire, SPI, FreeRTOS integration, InternalFS.
• NRF54L15-Clean-Arduino-core — sibling project by lolren. Bare-metal (no SoftDevice); we share API surface and have ported a handful of fixes (Print compat, BANDWIDTH cap behavior, XIAO TWIM22 routing, SAADC MAXCNT-in-bytes).
• Arduino-nRF5 by Sandeep Mistry — the original Arduino-style nRF52 BSP that Adafruit's was forked from.
• FreeRTOS, LittleFS, nrfx.

License

Mixed BSD-3-Clause / MIT / LGPL-2.1 depending on file provenance. See individual headers and LICENSE.