Pico SDK on OSX

Before starting to use Swift to build embedded software, it is essential to install the native SDK for the Raspberry Pico so that we have a basic toolchain installed. In the next post, we’ll see how to use Swift.

In this post we’ll learn how to:

  • Install the Pico SDK
  • Run a native example

Install the Pico SDK

First step:

cd ~
mkdir pico
cd pico

Second step:

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

# Set the PICO_SDK_PATH environment variable to where you just cloned the repo.
export PICO_SDK_PATH=/path/to/pico-sdk

cd pico-sdk
git submodule update --init
cd ..
git clone -b master https://github.com/raspberrypi/pico-examples.git

Third step:

# Install cmake
brew install cmake

# Install the arm eabi toolchain
brew install --cask gcc-arm-embedded

xcode-select --install

Fourth step:

git clone https://github.com/pimoroni/pimoroni-pico.git
cd pimoroni-pico
git submodule update --init
mkdir build

Fifth step:

cd build
cmake ..
make

Run a tative example

Create a directory for the project, in this directory create this main.c

#include <stdio.h>
#include "pico/stdlib.h"

int main() {

    const uint led_pin = 25;

    // Initialize LED pin
    gpio_init(led_pin);
    gpio_set_dir(led_pin, GPIO_OUT);

    // Initialize chosen serial port
    stdio_init_all();

    // Loop forever
    while (true) {

        // Blink LED
        printf("Blinking!\r\n");
        gpio_put(led_pin, true);
        sleep_ms(1000);
        gpio_put(led_pin, false);
        sleep_ms(1000);
    }
}

Now the CMakeLists.txt

# Set minimum required version of CMake
cmake_minimum_required(VERSION 3.12)

# Include build functions from Pico SDK
include($ENV{PICO_SDK_PATH}/external/pico_sdk_import.cmake)

# Set name of project (as PROJECT_NAME) and C/C   standards
project(blink C CXX ASM)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 17)

# Creates a pico-sdk subdirectory in our project for the libraries
pico_sdk_init()

# Tell CMake where to find the executable source file
add_executable(${PROJECT_NAME}
    main.c
)

# Create map/bin/hex/uf2 files
pico_add_extra_outputs(${PROJECT_NAME})

# Link to pico_stdlib (gpio, time, etc. functions)
target_link_libraries(${PROJECT_NAME}
    pico_stdlib
)

# Enable usb output, disable uart output
pico_enable_stdio_usb(${PROJECT_NAME} 1)
pico_enable_stdio_uart(${PROJECT_NAME} 0)

To compile:

mkdir build
cd build
cmake ..
make

After that, we should have the file blink.uf2 in the build directory. Connect your Pico to the computer, open it like a pendrive, and copy the file. Reboot the Pico; it should now blink.

External source that i used for this post:

https://www.digikey.com/en/maker/projects/raspberry-pi-pico-and-rp2040-cc-part-1-blink-and-vs-code/7102fb8bca95452e9df6150f39ae8422

https://forums.raspberrypi.com/viewtopic.php?t=357243

https://github.com/pimoroni/pimoroni-pico/blob/main/setting-up-the-pico-sdk.md

Swift Embedded

Until now, we have been able to use Swift to create applications for:

  • iPhone, iPad, Apple computers, Apple TV, Apple Watch
  • Servers with Vapor
  • Android using skip.tools

As of today, it is also possible to use Swift to create applications on embedded hardware (like Raspberry Pi Pico, Arduino, and so on).

Currently, the Swift Embedded version is in a preview status (you can find more information here), but it has the potential to become a real alternative to C/C++. Sure, at the moment, languages like Rust have an advantage in this area (not to forget MicroPython), but it’s a game worth playing.