1. ラズパイでSwiftを動かす – GPIOを使って、LEDを点滅させる

$ cat /proc/device-tree/model # Raspberry Pi device information
> Raspberry Pi 4 Model B Rev 1.2

$ cat /etc/os-release # OS information in Raspberry Pi
> PRETTY_NAME="Ubuntu 22.04 LTS"
> NAME="Ubuntu"
> VERSION_ID="22.04"
> VERSION="22.04 (Jammy Jellyfish)"
> VERSION_CODENAME=jammy

$ swift --version
> Swift version 5.6.1 (swift-5.6.1-RELEASE)
> Target: aarch64-unknown-linux-gnu

# Setup
# Step1 - Update system app
$ sudo apt update && sudo apt upgrade
# Install curl
$ sudo apt install curl
# Step2 - Run the quick install script
$ curl -s https://archive.swiftlang.xyz/install.sh | sudo bash
# Step3 - Choose which version of Swift to install
# Choose swift version
# Step4 - Install Swift
$ sudo apt install swiftlang
$ swift --version
# Ref: https://swift-arm.com/installSwift/

$ mkdir SwiftHomeLED
$ cd SwiftHomeLED
$ swift package init --name SwiftHomeLED --type executable

// (Omit)
    name: "SwiftHomeLED",
    dependencies: [
        .package(url: "https://github.com/uraimo/SwiftyGPIO.git", from: "1.0.0"),
    ],
    targets: [

// (Omit)
            dependencies: ["SwiftyGPIO"]),

import Foundation
import SwiftyGPIO
let gpios = SwiftyGPIO.GPIOs(for: .RaspberryPi4) // ①instance for raspberry pi4
let ledGpio = gpios[.P16]! // ②instance to control GPIO16
ledGpio.direction = .OUT // ③This time, current will flow, so use .OUT instead of .IN.

while(true) {
    Thread.sleep(forTimeInterval: 0.2) // ④Update GPIO16 value every 0.2 seconds
    ledGpio.value = ledGpio.value == 0 ? 1 : 0  // ⑤1 turns the LED on, 0 turns it off
}

wiringPiSetup: Unable to open /dev/mem or /dev/gpiomem: Permission denied.
  Aborting your program because if it can not access the GPIO
  hardware then it most certianly won't work

$ sudo apt install rpi.gpio-common
$ sudo adduser "${USER}" dialout
$ sudo reboot