Seeed Studio XIAO BLE nRF52840 Wireless Development Board-Standard with Onboard Antenna

Specifications

• Microcontroller: Nordic nRF52840 (32-bit ARM Cortex-M4 with FPU @ 64 MHz)
  
• Wireless Connectivity: Bluetooth Low Energy 5.4, Bluetooth Mesh, and NFC
  
• Onboard Antenna: Built-in 2.4 GHz antenna
  
• Flash Memory: 1MB internal Flash + 2MB onboard QSPI Flash
  
• SRAM: 256KB
  
• Operating Logic Voltage: 3.3V DC
  
• Input Voltage (USB Type-C): 5V DC
  
• Battery Input Voltage: 3.7V DC nominal (LiPo / Li-ion)
  
• Battery Charging IC: BQ25101
  
• Battery Charging Current: 50mA / 100mA 
  
• Ultra-Low Power Consumption: Approximately 5µA in standby mode
  
• Digital I/O Pins: 11 GPIO pins (PWM capable)
  
• Analog Input Pins: 6 ADC channels
  
• Interfaces: 1× I²C, 1× SPI, 1× UART, 1× NFC, 1× SWD
  
• Connector: USB Type-C (for power and programming)

Safety Warnings

• Logic Level Alert: The Nordic nRF52840 runs on strict 3.3V logic. Supplying 5V signals directly to any digital or analog pin will permanently burn out the MCU's internal ESD protection diodes and GPIO multiplexer.
• Battery Polarity Hazard: The BAT+ and BAT- solder pads on the underside of the PCB connect directly to the onboard PMIC. There is no reverse-polarity diode; reversing polarity even momentarily will destroy the charging controller.

Accessories Included in the Box

• 1× Seeed Studio XIAO BLE nRF52840 Development Board (with Onboard Antenna)
• 2× 7-pin 2.54mm pitch male header strips (unsoldered)

Frequently Asked Questions

• Can the Seeed Studio XIAO BLE nRF52840 communicate directly with iOS and Android devices without a custom SDK?
  Yes. The Seeed Studio XIAO BLE nRF52840 communicates natively over standard Bluetooth Low Energy (BLE 5.0) protocols, enabling direct wireless data exchange with standard mobile BLE terminal applications and Web Bluetooth browsers without requiring custom manufacturer SDKs or proprietary firmware patches.
• Which board core should be installed in the Arduino IDE when programming the XIAO BLE nRF52840?
  Install the "Seeed nRF52 mbed-enabled Boards" package and select the appropriate XIAO nRF52840 target in the Arduino IDE if your project specifically requires the standard ArduinoBLE library. Choosing the non-mbed community core is better suited for projects requiring low-level Nordic SoftDevice functions or the Adafruit_BluefruitLE_nRF52 library framework.
• Can this board be plugged directly into existing Seeed XIAO ecosystem carrier boards and shields?
  Yes. The XIAO BLE nRF52840 adheres strictly to the standard Seeed XIAO form factor and pinout, making it fully compatible with existing ecosystem accessories such as the Grove Shield for XIAO and the XIAO Expansion Board with OLED without requiring custom adapters or rewiring.
• Can the XIAO BLE nRF52840 be powered via USB-C and a 3.7V LiPo battery simultaneously?
  Yes. The board supports concurrent USB-C 5V power and a 3.7V single-cell LiPo battery soldered to the underside BAT pads. The integrated BQ25101 PMIC safely charges the connected LiPo cell while powering the system, and automatically transfers power to the battery when USB-C is disconnected.
• What is the maximum continuous current the onboard 3.3V regulator can supply to external sensors?
  While the onboard 3.3V low-dropout regulator is theoretically rated up to 250 mA, best practice is to limit external sensor loads to approximately 150–200 mA. This margin accounts for the nRF52840 SoC's peak wireless transmission currents and prevents thermal throttling or brownout resets.

• Why does the XIAO BLE nRF52840 power on but fail to enumerate as a serial device in the IDE?
  This most commonly occurs when using a charge-only USB-C cable that lacks physical D+ and D- data lines, providing power without data communication. A mechanically loose USB-C port, damaged cable conductors, or an intermittent hub connection will also cause erratic disconnection during sketch uploads.