Nordic's newest low-power radios keep the software story firmly in open-source territory, and Seeed Studio's latest thumbnail-sized boards lean into that. The XIAO nRF54LM20A and XIAO nRF54LM20A Sense are built around Nordic Semiconductor's nRF54LM20A, which pairs an Arm Cortex-M33 running at up to 128 MHz with a separate RISC-V coprocessor at the same clock. The SoC carries 512 KB of RAM and 2 MB of non-volatile memory on-chip, and Seeed adds another 8 MB of flash plus an nPM1300 PMIC for battery management on a board measuring just 2.1 x 1.75 cm (0.8 x 0.7 inches).
The radio is the reason to care. A single chip covers Bluetooth LE 6.0 (including Bluetooth Channel Sounding for distance measurement, coded PHY long range, and Mesh), IEEE 802.15.4 for Thread, Zigbee, and Matter, Nordic's proprietary 2.4 GHz protocol, NFC, and Amazon Sidewalk, with up to +10 dBm radiated output and an IPEX connector for an external antenna. That Thread and Matter support is what makes these boards interesting for anyone running a vendor-neutral smart home: paired with the OpenThread Border Router add-on in Home Assistant, which recently gained Thread 1.4 support alongside Matter 1.5.1, you can commission a device where you own the firmware and the network keys rather than routing through a vendor cloud.
Development stays on the Zephyr side of the fence. Seeed points users to Nordic's nRF Connect SDK and PlatformIO, both built on the Zephyr RTOS, and has published a MicroPython tutorial for lighter-weight work. The toolchain runs on Linux, macOS, and Windows, and nRF Connect SDK v3.3.0 includes Matter over Thread support for the nRF54LM20A SoC. Upstream Zephyr carries device tree files for the RISC-V FLPR (Fast Lightweight Peripheral Processor) under a dedicated cpuflpr board target alongside the Cortex-M33 application core, so the coprocessor can run its own Zephyr image for time-critical peripheral tasks or custom low-level protocols independently of the main application. The company explicitly notes that the Arduino IDE is not supported, though community project nrf54-arduino-core offers a bare-metal, Zephyr-free Arduino environment for the nRF54 series and is being adapted for the nRF54LM20A. Bare-metal mode does not support the nRF54LM20A USB stack, so an external debug probe is required for flashing outside the nRF Connect SDK. Getting-started material and feature guides are posted on the Seeed wiki. Compared to the earlier XIAO nRF54L15 boards, the new design exposes more I/O by alternating through-holes and castellated holes across its two 13-pin headers, reaching up to 20 GPIO with PWM, 5 ADC channels, dual I2C, UART, and SPI, and adds NFC pads while keeping the same XIAO footprint.
Power figures are the other headline. Running from a 3.7 V LiPo, the Sense model draws roughly 9.96 µA in light sleep and about 4.76 µA in System OFF deep sleep, dropping to 0.33 µA in ship mode, which keeps the board dormant during shipping until a button press or external power wakes it. The Sense variant also adds a PDM microphone and a 6-axis IMU with motion-triggered wake-up, over the base model. Both handle USB-C for power and programming and rate for -20°C to 70°C (-4°F to 158°F) operation.
The XIAO nRF54LM20A starts at roughly $10 (€9), with the Sense variant at about $16 (€15), available directly from the Seeed Studio store, and shipping begins 2026-07-15. Seeed has also confirmed nRF54LM20B variants adding an Axon NPU for tinyML workloads, expected at the end of Q3 2026.
