# Adafruit Feather 32u4 Bluefruit LE > Feather-format ATmega32u4 board with integrated nRF51822 Bluetooth LE, LiPo charging, native USB, 20 GPIO, and over-the-air firmware updates — an all-in-one BLE development board for iOS and Android connectivity. ## Quick Facts - **Brand:** Adafruit - **Board Type:** dev-board - **Price:** ~$29.95 - **Product Readiness:** developer - **CPU:** ATmega32u4 @ 8 MHz - **CPU Architecture:** AVR - **CPU Cores:** 1 - **RAM:** 2 KB - **Flash:** 32 KB - **Power:** 3.7V LiPo via JST or 5V Micro USB - **Operating Voltage:** 3.3V - **Dimensions:** 51.2 × 22.8 × 8 mm - **Weight:** 5.7g - **Antenna:** built-in chip antenna ## Connectivity - **Bluetooth:** Bluetooth LE 4.1 (nRF51822) ## Open Source - **Firmware:** Yes - **Schematics:** Yes - **PCB Layout:** Yes ## Compatible Firmware arduino, platformio ## Use Cases - bluetooth - ble-peripheral - wearable - iot - hid-devices - portable ## Components - **ATmega32u4** (mcu): 8-bit AVR with native USB at 8 MHz, 32KB flash, 2KB SRAM — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FDeviceDoc%2FAtmel-7766-8-bit-AVR-ATmega16U4-32U4_Datasheet.pdf&ref=openhardware.directory&product=adafruit-feather-32u4-bluefruit-le&source=md-export) - **nRF51822** (wireless): Nordic nRF51822 ARM Cortex-M0 Bluetooth LE 4.1 SoC with 256KB flash, AT command firmware, GATT and UART profiles — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Finfocenter.nordicsemi.com%2Fpdf%2FnRF51822_PS_v3.3.pdf&ref=openhardware.directory&product=adafruit-feather-32u4-bluefruit-le&source=md-export) - **MCP73831** (charger): Microchip MCP73831 100mA LiPo charge management IC — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FDeviceDoc%2F20001984g.pdf&ref=openhardware.directory&product=adafruit-feather-32u4-bluefruit-le&source=md-export) ## Protocols - **UART**: TX: D1, RX: D0 - **SPI**: MOSI: D16, MISO: D14, SCK: D15, SS: D10, BLE_CS: D8 - **I2C**: SDA: D2, SCL: D3 - **USB** - **Bluetooth LE** ## GPIO Map | Pin | Name | Type | Functions | |-----|------|------|-----------| | D0 | UART RX, External Interrupt 2 | UART | digital-input, digital-output, interrupt | | D1 | UART TX, External Interrupt 3 | UART | digital-input, digital-output, interrupt | | D2 | I2C SDA, External Interrupt 1 | I2C | digital-input, digital-output, interrupt | | D3 | I2C SCL, PWM, External Interrupt 0 | I2C | digital-input, digital-output, pwm, interrupt | | D4 | Digital I/O, Analog Input (A6) | — | digital-input, digital-output, analog-input | | D5 | Digital I/O, PWM | — | digital-input, digital-output, pwm | | D6 | Digital I/O, Analog Input (A7), PWM | — | digital-input, digital-output, analog-input, pwm | | D7 | Bluefruit nRF51822 IRQ line, External Interrupt 6 | — | digital-input, digital-output, interrupt | | D8 | Bluefruit nRF51822 SPI Chip Select | SPI | digital-output | | D9 | Battery voltage monitor, Analog Input (A9), PWM | — | digital-input, digital-output, analog-input, pwm | | D10 | SPI SS, Analog Input (A10), PWM | SPI | digital-input, digital-output, analog-input, pwm | | D11 | Bluefruit nRF51822 Reset | — | digital-output | | D12 | Digital I/O, Analog Input (A11) | — | digital-input, digital-output, analog-input | | D13 | Onboard red LED, PWM | — | digital-input, digital-output, pwm | | D14 | SPI MISO | SPI | digital-input, digital-output | | D15 | SPI SCK | SPI | digital-input, digital-output | | D16 | SPI MOSI | SPI | digital-input, digital-output | | A0 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | | A1 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | | A2 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | | A3 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | | A4 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | | A5 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | ## Available Software - **[Arduino IDE]()** (open-source) - **[PlatformIO]()** (open-source) ## Description ## Overview The Adafruit Feather 32u4 Bluefruit LE combines the ATmega32u4 Arduino-compatible microcontroller with an integrated Nordic nRF51822-based Bluetooth Low Energy module in the compact Feather form factor. This makes it a complete BLE development platform: the ATmega32u4 handles application logic and hardware interfacing while the Bluefruit module manages Bluetooth communication with iOS and Android devices. The BLE module is pre-loaded with Adafruit's Bluefruit firmware, supporting the Nordic UART profile for bidirectional data piping, programmable custom GATT services via AT commands, HID keyboard functionality, and over-the-air firmware updates for the BLE module itself. Two additional status LEDs indicate BLE connection state and activity. The ATmega32u4 runs at 8 MHz with 3.3V logic, providing 20 GPIO, 7 PWM, 10 analog inputs, hardware Serial/I2C/SPI, and native USB. Adafruit's Bluefruit Connect app for iOS and Android provides ready-to-use interfaces for UART communication, control pads, color pickers, and accelerometer data. Battery power is managed by an integrated 100mA LiPoly charger with JST connector and automatic USB/battery switchover. At 51.2 × 22.8 × 8mm and 5.7 grams, the board is well suited for wearable BLE peripherals, IoT sensors, HID accessories, and any project requiring smartphone connectivity with battery operation. ## Where to Buy - [Adafruit](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fproduct%2F2829&ref=openhardware.directory&product=adafruit-feather-32u4-bluefruit-le&source=md-export) — 29.95 ## Resources - [product](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fproduct%2F2829&ref=openhardware.directory&product=adafruit-feather-32u4-bluefruit-le&source=md-export) - [wiki](https://openhardware.directory/r?to=https%3A%2F%2Flearn.adafruit.com%2Fadafruit-feather-32u4-bluefruit-le&ref=openhardware.directory&product=adafruit-feather-32u4-bluefruit-le&source=md-export) ## Tags `feather`, `atmega32u4`, `bluetooth-le`, `ble`, `nrf51822`, `adafruit`, `bluefruit`, `lipo` ## Images ![Adafruit Feather 32u4 Bluefruit LE](https://nbg1.your-objectstorage.com/openhardware-directory/entities/adafruit-feather-32u4-bluefruit-le/b503c8f1ba88.jpg) ![Adafruit Feather 32u4 Bluefruit LE](https://nbg1.your-objectstorage.com/openhardware-directory/entities/adafruit-feather-32u4-bluefruit-le/db147afe6671.jpg) --- [View full device page](https://openhardware.directory/devices/adafruit-feather-32u4-bluefruit-le)