// This program achieves LED blink on Raspberry Pi with Go lang. // This is implemented with hard-coding and uses only main function.
package main
import (
"fmt"
"os"
"time"
)
func main() {
// Initialize GPIO25
fmt.Println("Initialize GPIO25")
fd, err := os.OpenFile("/sys/class/gpio/export", os.O_WRONLY|os.O_SYNC, 0666)
if err != nil {
fmt.Println("open /sys/class/gpio/export fails")
fmt.Println(err)
return
}
fmt.Fprint(fd, "25")
fd.Close()
// Check iinitialization result
fmt.Println("Check initialization result")
_, err = os.Stat("/sys/class/gpio/gpio25")
if err != nil {
fmt.Println("Export GPIO25 fails")
fmt.Println(err)
} else {
fmt.Println("Export GPIO25 succeeds")
}
// Set direction to out
fmt.Println("Set direction of GPIO25 to out")
fd, err = os.OpenFile("/sys/class/gpio/gpio25/direction", os.O_WRONLY|os.O_SYNC, 0666)
if err != nil {
fmt.Println("open /sys/class/gpio/gpio25/direction fails")
fmt.Println(err)
}
fmt.Fprint(fd, "out")
fd.Close()
// Start blink
fmt.Println("Start blink")
for i := 0; i < 20; i++ {
fd, err := os.OpenFile("/sys/class/gpio/gpio25/value", os.O_WRONLY|os.O_SYNC, 0666)
if err != nil {
fmt.Println("open /sys/class/gpio/gpio25/value fails")
fmt.Println(err)
}
if i%2 == 1 {
// Turn on LED
fmt.Fprint(fd, 1)
} else {
// Turn off LED
fmt.Fprint(fd, 0)
}
fd.Close()
time.Sleep(100 * time.Millisecond)
}
// End
fmt.Println("Start finalizing")
fd, err = os.OpenFile("/sys/class/gpio/gpio25/value", os.O_WRONLY|os.O_SYNC, 0666)
if err != nil {
fmt.Println("open /sys/class/gpio/gpio25/value fails")
fmt.Println(err)
}
// Turn off LED
fmt.Println("Turn off LED")
fmt.Fprint(fd, 0)
fd.Close()
fd, err = os.OpenFile("/sys/class/gpio/unexport", os.O_WRONLY|os.O_SYNC, 0666)
if err != nil {
fmt.Println("open /sys/class/gpio/unexport fails")
fmt.Println(err)
return
}
fmt.Fprint(fd, "25")
fd.Close()
fmt.Println("End finalizing")
}