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Q: Getting Started with XIAO nRF52840: Arduino Setup Guide

Updated 3 min read

Quick Answer

To get started with the XIAO nRF52840 in Arduino, add the Seeed board manager URL in Arduino IDE preferences, install the "Seeed nRF52" boards package, select your board and serial port, then upload the Blink sketch. The whole process takes about five minutes from opening the box to seeing your first LED flash.

What You Need

Grab a Seeed Studio XIAO nRF52840 Plus or XIAO nRF52840 Sense Plus, a USB-C cable, and a computer running Windows, macOS, or Linux. The Sense Plus variant adds a PDM microphone and 6-axis IMU for audio and motion sensing projects. Both boards pack a Nordic nRF52840 chip running at 64 MHz with Bluetooth 5.0, 256 KB RAM, and 2 MB onboard flash.

If you want to connect Grove sensors straight away, pick up a pack of Grove 4-pin conversion cables to bridge the XIAO pin headers to the Grove ecosystem. Browse the full Grove range for compatible sensors and actuators.

Step 1: Install Arduino IDE

Download the latest Arduino IDE from arduino.cc if you have not already. Version 2.x works fine with the Seeed nRF52 boards package. Install it and launch the application.

Step 2: Add the Seeed Board Manager URL

Open File > Preferences (or Arduino IDE > Settings on macOS). Find the Additional Boards Manager URLs field and paste this URL:

https://files.seeedstudio.com/arduino/package_seeeduino_boards_index.json

If you already have URLs in that field, add a comma after the last one and paste it at the end. Click OK.

Step 3: Install the Seeed nRF52 Boards Package

Go to Tools > Board > Boards Manager. Search for "seeed nrf52". You will see two packages:

  • Seeed nRF52 Boards — best for Bluetooth and low-power projects. If you use this one and need Serial output, add #include <Adafruit_TinyUSB.h> at the top of your sketch.
  • Seeed nRF52 mbed-enabled Boards — supports Serial out of the box, better for TinyML, IMU, and PDM microphone projects.

Install both. They will not conflict and give you the most flexibility.

Step 4: Select Your Board and Port

Connect the XIAO nRF52840 to your computer via USB-C. Go to Tools > Board and select Seeed XIAO nRF52840 (or the Sense variant if that is what you have). Then go to Tools > Port and pick the COM port that appeared when you plugged in the board.

Step 5: Upload Your First Sketch

Open File > Examples > 01.Basics > Blink. Change the LED pin to LED_BUILTIN (the XIAO has a built-in RGB LED). Click Upload. The sketch compiles and flashes to the board. After a few seconds, the onboard LED should start blinking.

Troubleshooting

If the COM port disappears after uploading, do not panic. Double-press the reset button on the XIAO to enter DFU (Device Firmware Update) mode. The board reappears as a USB mass storage device and the COM port comes back, ready for another upload.

If you see an "upload.tool.serial" error, make sure you installed both Seeed nRF52 board packages. The mbed-enabled package resolves most serial-related compilation issues.

What to Buy

For more XIAO boards and accessories, browse the maker collection.

FAQ

Q: Which Seeed nRF52 library should I use?
A: Use "Seeed nRF52 Boards" for Bluetooth and low-power work. Use "Seeed nRF52 mbed-enabled Boards" if you need Serial output without extra includes, or you plan to use the IMU, PDM microphone, or TinyML features.

Q: My XIAO does not show up as a COM port after flashing. What do I do?
A: Double-press the reset button to enter DFU mode. The board appears as a USB drive and the COM port returns. This is normal behaviour after a firmware upload.

Q: Can I use Arduino libraries like Adafruit_Bluefruit with this board?
A: Yes. The nRF52840 is widely supported in the Arduino ecosystem. Most Adafruit nRF52 libraries work with the Seeed board package, though you may need to adjust pin definitions to match the XIAO pinout.

Not sure which XIAO variant is right for you? Read our comparison of the XIAO nRF52840 vs Sense to see the differences side by side. For a broader introduction to the XIAO family, check out our overview of the Seeed Studio XIAO.