# Adafruit Feather M0 Bluefruit LE > ARM Cortex-M0+ dev board with Bluetooth LE (nRF51822) in the compact Feather form factor. Features 256KB flash, 32KB RAM, native USB, and a built-in LiPo charger for wireless wearable and IoT projects. ## Quick Facts - **Brand:** Adafruit - **Board Type:** dev-board - **Price:** ~$29.95 - **Product Readiness:** developer - **CPU:** ATSAMD21G18 ARM Cortex-M0+ @ 48 MHz - **CPU Architecture:** ARM Cortex-M0+ - **CPU Cores:** 1 - **RAM:** 32KB SRAM - **Flash:** 256KB - **Power:** 5V + LiPo - **Operating Voltage:** 3.3V - **Dimensions:** 51.2 × 22.8 × 8 mm - **Weight:** 5.7g - **Antenna:** Built-in PCB antenna ## Connectivity - **Bluetooth:** BLE 4.0 (nRF51822) ## Open Source - **Firmware:** Yes - **Schematics:** Yes - **PCB Layout:** Yes ## Compatible Firmware arduino, circuitpython ## Use Cases - iot - wearable - ble-peripheral - ble-sensor-node - prototyping ## Components - **ATSAMD21G18** (mcu): ARM Cortex-M0+ microcontroller at 48MHz with 256KB flash, 32KB RAM, native USB. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fimages%2Fproduct-files%2F2772%2Fatmel-42181-sam-d21_datasheet.pdf&ref=openhardware.directory&product=adafruit-feather-m0-bluefruit-le&source=md-export) - **nRF51822 (MDBT40)** (ble-module): Nordic Semiconductor BLE 4.0 SoC providing Bluetooth Low Energy connectivity via the MDBT40 module. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fcdn-shop.adafruit.com%2Fproduct-files%2F2267%2FMDBT40-P256R.pdf&ref=openhardware.directory&product=adafruit-feather-m0-bluefruit-le&source=md-export) ## Protocols - **SPI**: MOSI: PA16, MISO: PA19, SCK: PA17 - **I2C**: SDA: PA22, SCL: PA23 - **UART**: TX: PA10, RX: PA11 - **BLE**: ## GPIO Map | Pin | Name | Type | Functions | |-----|------|------|-----------| | PA11 | RX — UART Receive | UART | digital-input, digital-output | | PA10 | TX — UART Transmit | UART | digital-input, digital-output | | PA15 | D5 — GPIO / PWM | — | digital-input, digital-output, pwm | | PA20 | D6 — GPIO / PWM | — | digital-input, digital-output, pwm | | PA07 | D9 — GPIO / PWM / Analog | — | digital-input, digital-output, pwm, analog-input | | PA18 | D10 — GPIO / PWM | — | digital-input, digital-output, pwm | | PA16 | D11 — SPI MOSI | SPI | digital-input, digital-output | | PA19 | D12 — SPI MISO | SPI | digital-input, digital-output | | PA17 | D13 — SPI SCK / LED | SPI | digital-input, digital-output | | PA22 | SDA — I2C Data | I2C | digital-input, digital-output | | PA23 | SCL — I2C Clock | I2C | digital-input, digital-output | | PA02 | A0 — Analog In / DAC Out | — | analog-input, analog-output | | PB08 | A1 — Analog In | — | analog-input | | PB09 | A2 — Analog In | — | analog-input | | PA04 | A3 — Analog In | — | analog-input | | PA05 | A4 — Analog In | — | analog-input | | PB02 | A5 — Analog In | — | analog-input | ## Description ## Overview The Adafruit Feather M0 Bluefruit LE combines the ATSAMD21G18 ARM Cortex-M0+ microcontroller running at 48 MHz with a Nordic nRF51822-based Bluetooth Low Energy radio in the standard Feather form factor. With 256KB of flash and 32KB of RAM, it offers significantly more headroom than 8-bit AVR boards while staying compact enough for wearable and portable builds. The onboard Bluefruit LE module provides full BLE connectivity compatible with iOS, Android, macOS, and Windows 8+. Adafruit's Bluefruit LE Connect app enables UART bridging, HID profiles, and sensor streaming without writing a line of app code — making prototyping BLE-enabled devices fast and approachable. Power management is a first-class feature: a built-in 100mA LiPo charger with status LED lets you connect a single-cell 3.7V lithium polymer battery directly to the board. The USB port doubles as a programming interface and charger, and the regulator supplies a clean 3.3V at up to 500mA for peripherals. With 20 GPIO pins, 8 PWM outputs, 10 analog inputs, hardware SPI/I2C/UART, and native USB for HID or CDC, this board is well suited to BLE sensor nodes, wearables, BLE beacons, and any project needing a capable ARM M0 with wireless connectivity. ## Where to Buy - [Adafruit](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fproduct%2F2995&ref=openhardware.directory&product=adafruit-feather-m0-bluefruit-le&source=md-export) — 29.95 ## Resources - [product](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fproduct%2F2995&ref=openhardware.directory&product=adafruit-feather-m0-bluefruit-le&source=md-export) - [github](https://openhardware.directory/r?to=https%3A%2F%2Fgithub.com%2Fadafruit%2FAdafruit-Feather-M0-Bluefruit-LE-PCB&ref=openhardware.directory&product=adafruit-feather-m0-bluefruit-le&source=md-export) - [wiki](https://openhardware.directory/r?to=https%3A%2F%2Flearn.adafruit.com%2Fadafruit-feather-m0-bluefruit-le%2Foverview&ref=openhardware.directory&product=adafruit-feather-m0-bluefruit-le&source=md-export) - [datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fimages%2Fproduct-files%2F2772%2Fatmel-42181-sam-d21_datasheet.pdf&ref=openhardware.directory&product=adafruit-feather-m0-bluefruit-le&source=md-export) ## Tags `feather`, `ble`, `bluetooth`, `arm-cortex-m0`, `atsamd21`, `nrf51822`, `wearable`, `lipo-charger`, `adafruit` ## Images ![Adafruit Feather M0 Bluefruit LE](https://nbg1.your-objectstorage.com/openhardware-directory/entities/adafruit-feather-m0-bluefruit-le/1b6dee189413.jpg) ![Adafruit Feather M0 Bluefruit LE](https://nbg1.your-objectstorage.com/openhardware-directory/entities/adafruit-feather-m0-bluefruit-le/bdddbc19632b.jpg) --- [View full device page](https://openhardware.directory/devices/adafruit-feather-m0-bluefruit-le)