Design an RP2040 board with KiCad: Creating Raspberry Pi Pico-compatible PCBs 

Design an RP2040 board

with KiCad, 1st Edition

Design an RP2040 board with KiCad

by Jo Hinchliffe and Ben Everard

ISBN: 978-1-916868-13-7

Copyright © 2024 Jo Hinchliffe and Ben Everard

Printed in the United Kingdom

Published by Raspberry Pi Ltd., 194 Science Park, Cambridge, CB4 0AB

Editors: Ben Everard, Brian Jepson

Interior Designer: Sara Parodi

Production: Nellie McKesson

Photographer: Brian O’Halloran

Illustrator: Sam Alder

Graphics Editor: Natalie Turner

Publishing Director: Brian Jepson

Head of Design: Jack Willis

CEO: Eben Upton

September 2024: First Edition

The publisher, and contributors accept no responsibility in respect of any omissions or errors relating to goods, products or services referred to or advertised in this book. Except where otherwise noted, the content of this book is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0)

Welcome

KiCad is an amazing piece of free and open-source software that allows anyone, with some time and effort, to make high-quality PCB designs. Couple this amazing software with numerous PCB fabrication companies and even PCBA services — companies that will make and assemble your PCB designs — and there’s never been a better time to get into this aspect of making.

This book provides a gentle introduction to PCB design using the RP2040 microcontroller chip (the same chip that's at the heart of Raspberry Pi Pico). You'll learn the basics of creating schematics and PCB designs in KiCad and learn how to work with artifacts such as component footprints that you create yourself (or get from another source). You’ll find out how to get a PCB design manufactured — and populated with surface-mount components.

You’ll also learn how to make your PCBs stand out from more generic boards, whether by adding your own artwork, using the PCB as a structural component, or augmenting your design with 3D-printed parts. You’ll also find out about the difference PCB materials available, including flexible PCBs, and learn tips and tricks for working with fabricators to make sure your boards come out as intended.

You can find this book’s example code, errata, and other resources in its GitHub repository at hsmag.cc/kicad_book_files. If you’ve found what you believe is a mistake or error in the book, please let us know by opening an issue in that GitHub repository.

About the authors

Jo Hinchliffe (AKA Concretedog) is a constant tinkerer and is passionate about all things DIY space. He loves designing and scratch-building both model and high-power rockets and releases the designs and components as open source. He also has a shed full of lathes and milling machines and CNC kit!

Ben Everard enjoys working at the intersection of art and technology. He has a particular interest in light and his primary reason for making PCBs is to find more ways of adding LEDs to things. He lives in a house in Bristol with his wife, two daughters and too many animals.

Colophon

Raspberry Pi is an affordable way to do something useful, or to do something fun.

Democratising technology — providing access to tools — has been our motivation since the Raspberry Pi project began. By driving down the cost of general-purpose computing to below $5, we’ve opened up the ability for anybody to use computers in projects that used to require prohibitive amounts of capital. Today, with barriers to entry being removed, we see Raspberry Pi computers being used everywhere from interactive museum exhibits and schools to national postal sorting offices and government call centres. Kitchen table businesses all over the world have been able to scale and find success in a way that just wasn’t possible in a world where integrating technology meant spending large sums on laptops and PCs.

Raspberry Pi removes the high entry cost to computing for people across all demographics: while children can benefit from a computing education that previously wasn’t open to them, many adults have also historically been priced out of using computers for enterprise, entertainment, and creativity.

Raspberry Pi eliminates those barriers.

Raspberry Pi Press

store.rpipress.cc

Raspberry Pi Press is your essential bookshelf for computing, gaming, and hands-on making. We are the publishing imprint of Raspberry Pi Ltd. From building a PC to building a cabinet, discover your passion, learn new skills, and make awesome stuff with our extensive range of books and magazines.

The MagPi

magpi.raspberrypi.com

The MagPi is the official Raspberry Pi magazine. Written for the Raspberry Pi community, it is packed with Pi-themed projects, computing and electronics tutorials, how-to guides, and the latest community news and events.

Chapter 1

Working with schematics

Before you design the PCB, you must design the circuit

PCB design has a steep learning curve. With that in mind, we want to start this book with a hack. In the first two chapters, you’ll create a PCB design to the point of getting it manufactured. To ease up on the learning curve, you will cut some corners. Don’t worry, we’ll explain what corner were cut, and you’ll learn the correct approach in subsequent chapters, once you have the basics down.

Figure 1-1: The board you’ll start to design in this chapter

Start by downloading and installing KiCad from kicad.org — at the time of writing, the stable version was 8. KiCad is available across a wide range of operating systems – Windows, macOS, and lots of Linux distributions.

With it installed, click on the main blue Ki KiCad icon to open the main application. You should see a screen that looks like Figure 1-2. KiCad isn’t really a single application, it’s more like a suite of applications that work together. While you can jump into any application from here, the most common workflow for KiCad is to first work in the Schematic Editor and after creating a schematic, move to the PCB Editor to lay out the PCB physically.

You’ll create an add-on board for the Raspberry Pi Pico. It’s going to be a prototyping or ‘kludge’ board with not too many features on it. It’s going to have all the Pico pins broken out to through-hole pads, it will have a power-indicating LED, and it will have a reset button. After this, any spare area on the board will have a grid of simple through-hole pads (sometimes called a prototyping area) on it to allow you to connect experiments to the board. It’s a bit rudimentary but will help you learn some KiCad basics.

Figure 1-2: The opening page of KiCad with the different applications that make up the KiCad suite listed

Your first action should be to set up a new project. Click File > New Project to create a new project. It’s worth putting projects into their own folder as each KiCad project generates around five project files and a folder in which it automatically generates some project backup files.

Once the new project is created, open the Schematic Editor application by clicking the top icon. The first time you run the Schematic Editor, KiCad will ask you to configure your global symbol library table. Choose Copy default global symbol library table (recommended) and click OK.

Quick Tip

If you hover over any tool icon in KiCad, you get a description of the tool. We’ll use these tooltips to describe tool icons throughout this book.

You’ll see a blank page ready for you to draw a schematic (Figure 1-3). In the lower right-hand corner, you will see a small collection of text boxes which include various fields for the name of the sheet, the revision number of the schematic, and more. If you click somewhere on this section and then press the E key, the Page Settings dialogue will appear. You can edit this to add any text details or comments you want to add to this section, but you can also change the page dimensions (it defaults to A4), the orientation, and more. Experiment inserting text into the Page Settings window to see where the text appears on the schematic.

Figure 1-3: A blank Schematic sheet with text boxes for various schematic labelling and

version numbering

With your page set up, you can now begin to add schematic symbols to the schematic. The most correct way to make a Pico add-on board would be to place a Pico in the schematic and connect everything to it, but you are going to use a workaround to do this in a much simpler way. The main idea of the target add-on board is for you to be able to solder in rows of header sockets so that you can connect it onto the pins of a Pico. In turn, you also still want to be able to solder to those pins, so you need each side row of pins to be broken out to another collection of pads.

To do this add two 20-pin connectors, one on each side of the schematic. To add the first one, click the Add a Symbol icon — the third icon down on the right-hand column. The first time you click this