Adafruit RP2040 User Manual

Quickstart - Raspberry Pi RP2040 with BLE and CircuitPython

Created by Brent Rubell

Last updated on 2021-03-26 11:44:36 PM EDT

2 3

3

7

7 7

9

9 9

11

11 12 12 13 15

16 16 18

18 18 18 20

23 27 28

Guide Contents

Guide Contents Overview

Parts

Bluetooth Low Energy Basics

Bluetooth Terms Making a Bluetooth Connection

Assembly

Adafruit Feather RP2040 Wiring Raspberry Pi Pico RP2040 Wiring

Upgrade RP2040 AirLift Firmware

Upload Serial Passthrough Code Download NINA Firmware Flash AirLift using Web Serial ESPTool Enable Chrome's Web Serial API Flash AirLift using esptool.py

Burning nina-fw with esptool Verifying the Upgraded Firmware Version Code Usage

Install CircuitPython Libraries Install Adafruit Bluefruit LE Connect App Code Setup Code Usage

NeoPixel Color Adapting Existing CircuitPython BLE Code for AirLift BLE BLE Technical Details

Overview

Add Bluetooth Low Energy (BLE) connectivity to your Raspberry Pi RP2040 project by adding an Adafruit AirLift ESP32 co-processor. The AirLift's ESP32 module can be placed into either a WiFi mode (we've published a guide about using the AirLift's WiFi mode with Pico here (https://adafru.it/RlC)) or BLE mode, giving you the option of adding two different methods of wireless connectivity to your RP2040 project.

This guide will cover getting started using BLE to connect an RP2040 board with the Bluefruit LE Connect App along with examples for a UART echo server and wirelessly changing the color of a NeoPixel RGB LED.

A few notes before we begin:

You can not use the WiFi and BLE mode on the Adafruit AirLift simultaneously , so select your

transport

wisely

(https://adafru.it/Cio).

CircuitPython's AirLift support only provides BLE peripheral support , BLE central support is under development. This means you can not connect the RP2040 to BLE devices such as heart rate monitors or thermometers, but you can make the RP2040 act as a BLE peripheral.

Parts

Adafruit Feather RP2040

A new chip means a new Feather, and the Raspberry Pi RP2040 is no exception. When we saw this chip we thought "this chip is going to be awesome when we give it the Feather... Out of Stock

Out of

Stock

Raspberry Pi Pico RP2040

The Raspberry Pi foundation changed single-board computing when they released the Raspberry Pi computer, now they're ready to... Out of Stock

Adafruit AirLift FeatherWing – ESP32 WiFi Co-Processor

Give your Feather project a lift with the Adafruit AirLift FeatherWing - a FeatherWing that lets you use the powerful ESP32 as a WiFi co-processor. You probably have your... $12.95 In Stock

Out of

Stock

Add to Cart

Adafruit AirLift – ESP32 WiFi Co-Processor Breakout Board

Give your plain ol' microcontroller project a lift with the Adafruit AirLift - a breakout board that lets you use the powerful ESP32 as a WiFi co-processor. You probably... $9.95 In Stock

1 x FeatherWing Doubler FeatherWing Doubler - Prototyping Add-on For All Feather Boards

1 x USB-C Cable USB-C Cable for RP2040 Feather

1 x USB Cable USB cable - USB A to Micro-B - 3 foot long

1 x Breadboard Full sized breadboard

1 x Breadboarding Wires Breadboarding wire bundle

Add to Cart

Out of

Stock

Add to Cart

Bluetooth Low Energy Basics

The nRF52840 uses Bluetooth Low Energy, or BLE. BLE is a wireless communication protocol used by many devices, including mobile devices. You'll be able to communicate with your nRF52840 board using your mobile phone!

There's a few terms and concepts commonly used in BLE with which you may want to familiarise yourself. This will help you understand what your code is doing when you're using CircuitPython and BLE.

The major concepts can be broken down into two categories: connection set up and communication. The first deals with setting up connections between devices, such as between your mobile phone and the nRF52840 board. The second deals with communication between the devices once they are connected.

Bluetooth Terms

Central - The host computer. This is often a mobile device such as a phone or tablet, or it could be a desktop or laptop. Peripheral - The connected device. Examples of peripherals are: heart rate monitor, smart watch, or fitness tracker. The CircuitPython code we have so far is designed to make the Adafruit nRF52840 devices work as peripherals. Advertising - Information sent by the peripheral during connection set up. When a device advertises, it is transmitting the name of the device and describing its capabilities. The central looks for an advertising peripheral to connect to, and uses that information to determine what the peripheral is capable of. Service - A function the peripheral provides. The peripheral advertises its services. A really common service that we use is the UART service, which acts like a hardware UART and is a way of bidirectionally sending information to and from devices. Packet - Data transmitted by a device. BLE devices and host computers transmit and receive data in small bursts called packets.

Making a Bluetooth Connection

To use these terms in the context of connecting to your Adafruit nRF52840:

You run CircuitPython code that makes your board act as a peripheral by advertising its name and the services it's capable of. You start up Adafruit's Bluefruit LE Connect app on an Android or iOS device in central mode, that device becomes the central, and begins listening for the peripheral. You set up the connection between the nRF52840 peripheral and the Bluefruit LE Connect app, and the app discovers the details about the services that the peripheral is capable of. Once this connection is made, you can use CircuitPython code to read packets sent from the Bluefruit LE Connect app to your nRF52840 board. For example, you can receive data describing screen button presses or RGB color values.

Now that you have a general idea of basic BLE terms and concepts, it's time to install the Bluefruit LE Connect application, and run some CircuitPython demos!

Assembly

Adafruit sells Airlift hardware in multiple (https://adafru.it/JDc) form (https://adafru.it/EDW)

factors (https://adafru.it/RlD) in order to be compatible with many microcontroller boards. While each

microcontroller board and airlift hardware combination has its own wiring scheme, we suggest either using the wiring below or referencing the AirLift product guide.

Adafruit Feather RP2040 Wiring

To use the AirLift FeatherWing with BLE, you will need to solder the three jumpers closed on the bottom of the AirLift FeatherWing:

After soldering the jumpers closed, we suggest using the

FeatherWing Doubler (https://adafru.it/kBi) to connect a

Feather RP2040 and an AirLift FeatherWing side-by-side.

Raspberry Pi Pico RP2040 Wiring

If you're using a Raspberry Pi Pico RP2040, make the following connections between the Pico RP2040 and an Adafruit AirLift breakout.

 You MUST use the Pico's VSYS pin for powering the AirLift Breakout.

Adafruit RP2040 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual