Seeed Studio XIAO nRF52840
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The Seed Studio XIAO nRF52840 is a microcontroller board based around the nRF52840 microcontroller. It is typically connected to a Wio-SX1262 LoRa module to enable long-range wireless communication.
Contents
Firmware
As of July 2026, the XIAO nRF52840 is not supported by any known firmware version.
Bootloader
To enable OTA firmware updates on the XIAO, the OTAFIX bootloader can be flashed to the board. This allows for the board's firmware to be updated over Bluetooth, which is especially useful when updating solar nodes in hard-to-reach places. However, for this feature to be useful, the firmware must provide a way to remotely put the board into device firmware upgrade (DFU) mode. Entering DFU mode normally requires physical access to the device.
For the XIAO specifically, it is important to verify which bootloader version is currently flashed to the board prior to flashing the new bootloader. If the board came with the sense bootloader, it should be flashed with the sense variant of the OTAFIX bootloader.cite-ref-1[1]
Power
Like most other microcontroller boards, the XIAO can be powered through its USB port. It can also receive 5 V power directly through its VBUS pin, so long as a diode is placed between the power source and the pin.cite-ref-wiki-2-0[2]
It also features solder pads on the back of the board for connecting a standard 3.7 V Li-ion or LiPo battery. These pads are very small, so a soldering iron with a fine tip is required. The small size of the pads also poses the risk of short-circuiting the battery. Shorting an unprotected Lithium battery can result in a fire, so a protected battery should always be used.
When connected to 5 V power, the XIAO charges batteries at 100 mA by default. The charging current can be decreased to 50 mA in firmware. The battery management IC in use is the BQ25101.cite-ref-wiki-2-1[2]
References
cite-note-11. ↑ "Adafruit nRF52 Bootloader with Enhanced OTA DFU".
cite-note-wiki-22. ↑ "Getting Started with Seeed Studio XIAO nRF52840 Series".
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