Use Go lang to control GPIO on pcDuino

In this post, we show how to use Go lang to control GPIO on pcDuino.

If you have updated the image, sometimes, GPIO is not loaded by default. We need to use commands to load GPIO:

$sudo modprobe gpio
$sudo modprobe adc
$sudo modprobe pwm

The main program is as follows:

package main
import (
"fmt"
"./gpio"
"time"
)
func main() {
g, err := gpio.NewGPIOLine(7,gpio.OUT)
if err != nil {
fmt.Printf("Error setting up GPIO %v: %v", 18, err)
return
}
blink(g, 100)
g.Close()
}
func blink(g *gpio.GPIOLine, n uint) {
fmt.Printf("blinking %v time(s)\n", n)
for i := uint(0); i < n; i++ {
g.SetState(true)
time.Sleep(time.Duration(1000) * time.Millisecond)
g.SetState(false)
time.Sleep(time.Duration(1000) * time.Millisecond)
}
}

The package used is shown below:

package gpio
 
import (
     "fmt"
     "os"
)
 
type GPIOLine struct {
     Number uint
     fd     *os.File
}
 
const (
     IN = iota
     OUT
)
 
func NewGPIOLine(number uint, direction int) (gpio *GPIOLine, err error) {
     gpio = new(GPIOLine)
     gpio.Number = number
 
        err = gpio.SetDirection(direction)
 
     gpio.fd, err = os.OpenFile(fmt.Sprintf("/sys/devices/virtual/misc/gpio/pin/gpio%d", gpio.Number), os.O_WRONLY|os.O_SYNC, 0666)
     if err != nil {
          return nil, err
     }
     return gpio, nil
}
 
func (gpio *GPIOLine) SetDirection(direction int) error {
     df, err := os.OpenFile(fmt.Sprintf("/sys/devices/virtual/misc/gpio/mode/gpio%d", gpio.Number), os.O_WRONLY|os.O_SYNC, 0666)
     if err != nil {
          return err
     }
     fmt.Fprintln(df, "out")
     df.Close()
     return nil
}
 
func (gpio *GPIOLine) SetState(state bool) error {
     v := "0"
     if state {
          v = "1"
     }
     _, err := fmt.Fprintln(gpio.fd, v)
     return err
}
 
func (gpio *GPIOLine) Close() {
     gpio.fd.Close()
}

The code can be downloaded from pcduinogo.tar

Please download the above code to “$HOME/mygo”. To run the code, we do “$go run blink.go”.