gpio.go

package main

// Pinout             https://forums.ni.com/legacyfs/online/202279_Main%20Pinout.png
// Pibrella (Python)  https://github.com/pimoroni/pibrella/blob/master/library/pibrella/__init__.py
// go-rpio            https://github.com/stianeikeland/go-rpio/blob/master/rpio.go

import (
	"fmt"
	"github.com/stianeikeland/go-rpio"
	"os"
	"os/signal"
	"time"
)

const (
	red    = rpio.Pin(27)
	yellow = rpio.Pin(17)
	green  = rpio.Pin(4)
)

func cleanup() {
	red.Low()
	yellow.Low()
	green.Low()

	rpio.Close()
}

func setPin(pin rpio.Pin, state bool) {
	if state {
		pin.High()
	} else {
		pin.Low()
	}
}

func main() {
	c := make(chan os.Signal, 1)
	signal.Notify(c, os.Interrupt)
	go func() {
		for range c {
			cleanup()
			os.Exit(1)
		}
	}()

	if err := rpio.Open(); err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	red.Output()
	yellow.Output()
	green.Output()

	i := 0

	for {
		i++

		setPin(red, i&1 == 1)
		setPin(yellow, i>>1&1 == 1)
		setPin(green, i>>2&1 == 1)

		time.Sleep(time.Second)
	}
}