Adafruit Feather nRF52840 Express - (AD43412)

Description:

The Adafruit Feather nRF52840 Express is the new Feather family member with Bluetooth Low Energy and native USB support, featuring the nRF52840! It's our take on an 'all-in-one' Arduino-compatible + Bluetooth Low Energy with built-in USB and battery charging. With its native USB, it's even ready to join CircuitPython.

This chip has twice the flash and four times the SRAM of its predecessor, the nRF52832: 1MB flash and 256KB SRAM. Compared to the nRF51, this board has 4 to 8 times more.

For this chip, we've added Arduino IDE support – you can program the nRF52840 chip directly to get the most out of the Cortex-M4 processor, and then call the Nordic SoftDevice radio stack when you need to communicate over BLE. Since the underlying API and peripherals are the same for the '832 and '840, you can power up your old nRF52832 projects with the same code, with just a recompile!

We also picked this chip for our first BLE-capable CircuitPython board! CircuitPython works best with disk drive access, and this is the only native BLE-plus-USB chip that has enough memory to run the tiny Python interpreter. The ample RAM and speedy Cortex M4F chip make it a great choice.

Note that we only offer BLE stack support in Arduino at this time. CircuitPython BLE stack support is still under development!

It includes a ton of awesome peripherals: tons of GPIO, analog inputs, PWM, timers, etc. And best of all: it has native USB! Finally, no more need for a separate serial USB chip like the CP2104 or FT232. Serial is managed as a USB CDC descriptor, and the chip can act as a keyboard, mouse, MIDI device, or even a disk drive. (Note that we only offer CDC support for Arduino at this time.)

Other improvements we've included are an additional "USER" switch that lets you trigger OTA updates (or whatever you prefer), a NeoPixel LED for status updates, 2MB of QSPI Flash memory for storing CircuitPython files, and an SWD connector.

We have quite a few BTLE-enabled Feathers (it's a popular protocol!), so check out our BT Feather guide for comparative information.

We pre-program the chip with our UF2 bootloader, which can use command line UART programming with nrfutil (we use this for Arduino) or drag-and-drop mass storage, for CircuitPython installation and also because mass storage bootloaders make firmware upgrades super easy. Want to program the chip directly? You can use our command-line tools with your favorite editor and toolchain. If you want to use an SWD programmer/debugger (for even more advanced usage), we have a standard 0.05" 2x5 connector.

And best of all: we've taken care of setting up the low-level BLE stack so you can focus on your project from day one! The example code works seamlessly with our existing iOS and Android app.

Features:

• ARM Cortex M4F (with hardware floating-point acceleration) at 64 MHz
• 1 MB flash and 256 KB SRAM
• Open source native USB stack, pre-programmed with the UF2 bootloader
• 2.4 GHz radio compatible with Bluetooth Low Energy (more information available in the nRF52840 product specification)
• FCC/IC/TELEC certified module
• Output power up to +8 dBm
• 1.7 V to 3.3V operation with internal linear and DC/DC voltage regulators
• 21 GPIO, 6 x 12-bit ADC pins, up to 12 PWM outputs (3 PWM modules with 4 outputs each)
• Pin #3: Red LED for general blinking, NeoPixel for color feedback
• Power/enable pin
• Dimensions: 51 mm x 23 mm x 7.2 mm without soldered connectors
• 4 mounting holes
• Reset button
• SWD connector for debugging
• Works out of the box with all our Adafruit FeatherWings! (Even those that use UART, like the GPS FeatherWing).

Bluetooth Low Energy is the new low-power wireless protocol in the 2.4 GHz spectrum. In particular, it is the only wireless protocol supported by iOS without special certification and is compatible with all modern smartphones. This makes it ideal for portable projects that require an iOS or Android phone or tablet. It is also compatible with Mac OS X and Windows 8+.

For ease of use in portable projects, we have added a connector for any of our 3.7 V lithium polymer batteries and a built-in battery charger. You don't need a battery, as it works perfectly directly from the micro USB connector. But, if you have a battery, you can take it on the go and connect it to USB to recharge. The Feather will automatically switch to USB power when available. We also connected the battery via a divider to an analog pin, so you can measure and monitor its voltage and detect when it needs recharging.

The power of Bluefruit LE

The Bluefruit LE module is a Nordic nRF52840 chipset, which can be used both as a main microcontroller and as a Bluetooth Low Energy interface. Most people will be happy to use Nordic's standard UART RX/TX connection profile (code is included!). In this profile, Bluefruit acts as a data channel that can transparently transmit data between your iOS or Android device. You can use our iOS or Android app, or create your own to communicate with the UART service.

The board is capable of much more than just sending text strings over the air! Thanks to an Arduino library, you have full control over the device's behavior, including the ability to define and manipulate your own GATT services and characteristics, or change how the device advertises itself to other Bluetooth Low Energy devices.

Use the Bluefruit app to get your project started.

With our Bluefruit app for iOS or Android, you can quickly prototype your project using your iOS or Android phone or tablet as a controller. We have a color picker, quaternion/accelerometer/gyroscope/magnetometer or location (GPS), and an 8-button gamepad. This data can be read via Bluetooth Low Energy (BLE) and processed directly with the nRF52 microcontroller.

It comes fully assembled and tested, with a USB bootloader that allows you to quickly use it with the Arduino IDE or to install CircuitPython. We also include a header so you can solder it and connect it to a solderless breadboard. It does not include a lithium polymer battery or microUSB cable (but we have many options in the store if you want one!).

Reference link