Pico C/C++ Development Using Windows

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2022-09-20 | By Pimoroni

License: See Original Project Raspberry Pi MCU

Guide by Pimoroni

If you want to use C or C++ to program your Raspberry Pi Pico (or other ‎RP2040 board) but would quite like to develop from the comfort of your ‎Windows PC - read on! This quick guide will show you how to set up and run ‎a basic C/C++ development process on a Windows machine using our ‎preferred method - Windows Subsystem for Linux (WSL).‎

WSL

WHAT IS WSL AND WHY SHOULD I USE IT?‎

Windows Subsystem for Linux is a tidy way of setting up a Linux virtual ‎machine on your Windows PC, with minimal impact on system performance ‎and without the faff of a traditional dual boot setup.‎

There are instructions in the Raspberry Pi Pico Getting Started guide for ‎installing the Pico SDK and toolchain on a Windows machine natively but it's ‎quite a complicated process - we've found using WSL and installing the ‎toolchain on a virtual Linux machine to be much more straightforward.‎

ASSUMPTIONS

You're using an up-to-date version of Windows 10 (version 2004 or ‎higher). WSL should also work on Windows 11
Your computer's hardware is capable of running a virtual machine ‎‎(most modern motherboards compatible with Windows 10 should be ‎fine)
You're happy running commands from the terminal

If you're brand new to Pico/RP2040/microcontrollers in general, we'd strongly ‎suggest trying MicroPython before you attempt C/C++ - check out ‎our beginner friendly tutorial!‎

INSTALLING WSL

Open up an administrator command prompt on your Windows machine (find ‎it in the start menu or via the search box, right click on it and choose 'Run as ‎Administrator') and type:‎

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wsl --install

This command will execute all the necessary steps to set up WSL and install ‎an Ubuntu distribution for you, discreetly running in the background of your ‎Windows machine. Magic! If you want to know exactly what the command ‎does before you run it or want to choose a different Linux distro, check ‎out this guide.‎

Note - we got this error after running that command, so we had to go into ‎our computer's BIOS and turn on a CPU setting to enable virtualisation ‎support.‎

You'll need to reboot your Windows machine once you've installed WSL.‎

Installing the Pico SDK and Toolchain

Next, we're going to install the Pico SDK on your new Linux virtual machine, ‎along with the software needed to build the examples.‎

You can find your VM in the Windows start menu, named 'Ubuntu' - click on it ‎to open up a terminal. If it's the first time you've fired it up, you'll be prompted ‎to set up a username and password - remember the password, you'll need it ‎in a bit.‎

Once you've done that, you should have a terminal prompt that looks ‎something like this (but, hopefully with your username).‎

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Make sure you run the following commands at this prompt, identifiable by the ‎orange Ubuntu blob, to execute them on the virtual machine. If you try to run ‎them in a Windows command prompt things will get confusing.‎

Start off with a sudo apt update to make sure all your sources are up to date (you ‎might be prompted to enter the password you just set up the first time you ‎use a sudo command). Then you can use the apt package manager to install ‎the software that the Pico SDK needs to be able to compile and build files:‎

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sudo apt update
sudo apt install git cmake gcc-arm-none-eabi libnewlib-arm-none-eabi build-essential libstdc++-arm-none-eabi-newlib

Make a new directory to keep everything Pico-related in and navigate into it:‎

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cd ~/
mkdir pico
cd pico

Then clone the Raspberry Pi Pico SDK (you'll always need to have this ‎installed for Pico dev):‎

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git clone -b master https://github.com/raspberrypi/pico-sdk.git --recursive

The --recursive flag tells git to also download any external modules that are ‎referenced in the repo. Not all repos use external modules, but pico-sdk and ‎some of the others mentioned below do.‎

Downloading Additional Repos

You'll probably want to download some example code to build next, like the ‎official Raspberry Pi Pico examples.‎

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git clone -b master https://github.com/raspberrypi/pico-examples.git

If you want to play with Pimoroni addons, boards or breakouts, you'll want to ‎grab our pimoroni-pico repo:‎

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git clone -b main https://github.com/pimoroni/pimoroni-pico.git --recursive

Or if you want to program a PicoSystem with C/C++, you'll need:‎

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git clone -b main https://github.com/pimoroni/picosystem.git

The pico directory on your virtual machine should now contain a number of ‎other directories that contain the cloned repos:‎

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Building From the Terminal

Let's build the pico-examples and get the LED blinking on your Pico. Before you ‎can configure and build them, you'll need to set the path to the Pico SDK with:‎

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export PICO_SDK_PATH=../../pico-sdk

Create a build directory in pico-examples and navigate into it:‎

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cd ~/pico/pico-examples
mkdir build
cd build

Then...‎

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cmake ..‎

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‎... and:‎

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make -j8‎

You could just use make here but adding -j8 runs parallel processes and ‎speeds up this step considerably. A good rule of thumb is to set this number ‎to however many CPU cores you have.‎

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If everything worked correctly, the build directory should now contain a bunch ‎more directories with files in them, including some tasty .uf2 files ready to be ‎flashed to your Pico.‎

Copying Files to your Pico

If Linux is not your first love, you might find moving files about using the ‎command line to be tedious. Let's use WSL's Windows integration to make it ‎easy - type‎

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explorer.exe .‎

to open your build directory in Windows Explorer.‎

Put your Pico into FS / bootloader mode by holding down the BOOTSEL ‎button whilst plugging it into your PC - it should now show up as a drive ‎called RPI-RP2. Once you've navigated to your chosen uf2 file, you can just ‎drag it over to the RPI-RP2 drive on the left to copy it to your Pico - simples.‎

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Building Other Examples

You can use exactly the same process to build the examples in pimoroni-‎pico and picosystem - just create a build directory within the appropriate folder ‎and navigate into it before building as above.‎

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Next Steps

To start modifying the example code, you'll need to hunt down and edit ‎the *.c or *.cpp source files. You can do this from the Linux command line (nano ‎whatever.c) or you can use that useful explorer.exe . command to navigate to them ‎with Windows Explorer, and open and edit them in a nice editor ‎like Notepad++.‎

If you'd rather have all the conveniences of a fully featured development ‎environment with code auto-completion and tons of handy extensions, you ‎might want to consider hooking your WSL install up to Visual Studio Code. ‎You can find out more about how to do that in this fine tutorial!‎

Troubleshooting

CMAKE PROBLEMS: PICO-SDK NOT FOUND

If the cmake step fails, you might get an error that looks something like this:‎

error_7

Oops - looks like cmake can't find the SDK due to a typo in our export ‎PICO_SDK_PATH. You'll see a similar error if you forget to set the path at all!‎

You can run the command again to set the path to your pico-sdk directory ‎correctly. If your directory structure differs from the way we've set it up, be ‎sure to change the path accordingly. It can be an absolute path rather than a ‎relative path if you want -‎

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export PICO_SDK_PATH=~/pico/pico-sdk

Before you try the cmake .. again though, make sure to delete and recreate ‎the build directory (rm -r build). A failed cmake creates files that can make errors ‎persist in a confusing manner.‎

That's all folks!‎