[vc_row][vc_column][vc_column_text]It is a common phenomenon that the each operation of Linux is  read-write operation, so is to the program that control the GPIO of pcDuino.

The path for pcDuino GPIO pin saved is /sys/devices/virtual/misc/gpio/pin/

Pin controller corresponding file saved in /sys/devices/virtual/misc/gpio/mode/

[/vc_column_text][vc_tour][vc_tab title=”Part list” tab_id=”1393684236-1-19″][vc_column_text]1. [bigcommerce link=”/5mm-green-led-module-of-linker-kit-for-pcduino-arduino/” target=”_blank”]LED Module[/bigcommerce]   x 1

2. Male to female DuPont line    x 2

3. [bigcommerce link=”/pcduino-an-minipc-with-arduino-headers-ubuntu-android-google-tv/” target=”_blank”]pcDuino[/bigcommerce]   x  1

[/vc_column_text][/vc_tab][vc_tab title=”Diagram wiring” tab_id=”1393684236-2-67″][vc_column_text]led  GND pin – > cDuino  GND pin

led  SIG  – >  pcDuino  GPIO 1 pin

[/vc_column_text][/vc_tab][vc_tab title=”Test code” tab_id=”1393684348633-2-5″][vc_column_text]First,create GPIO_pin entity class. code as follows:

package com.test;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class GPIO_Pin {

    private String modeURI = "/sys/devices/virtual/misc/gpio/mode/";
    private String statusURI = "/sys/devices/virtual/misc/gpio/pin/";
    private int pin = 0;
    public static final String HIGH = "1", LOW = "0", INPUT = "0", OUTPUT = "1", INPUT_PU = "8";

    public GPIO_Pin(int pin) {
        modeURI += "gpio" + pin;
        statusURI += "gpio" + pin;
        this.pin = pin;
    }

    public GPIO_Pin(String pin) {
        // Finalize file paths
        modeURI += "gpio" + pin;
        statusURI += "gpio" + pin;
        this.pin =Integer.parseInt(pin);
    }

    public int getPin() {
        return pin;
    }

    public void overrideURI(String uri) {
        modeURI = uri + "mode/gpio" + pin;
        statusURI = uri + "pin/gpio" + pin;
    }

    public void setMode(String mode) {
        writeToFile(getModeURI(), mode);
    }

    public void set(String state) {
        writeToFile(getStatusURI(), state);
    }

    public void setHIGH() {
        writeToFile(getStatusURI(), HIGH);
    }

    public void setLOW() {
        writeToFile(getStatusURI(), LOW);
    }

    public void setModeINPUT() {
        writeToFile(getModeURI(), INPUT);
    }

    public void setModeOUTPUT() {
        writeToFile(getModeURI(), OUTPUT);
    }

    public void setModeINPUT_PU() {
        writeToFile(getModeURI(), INPUT_PU);
    }

    public String getModeURI() {
        return modeURI;
    }

    public String getStatusURI() {
        return statusURI;
    }

    public String getPinMode() {
        try {
            BufferedReader reader = new BufferedReader(new FileReader(getModeURI()));
            String data = reader.readLine();
            reader.close();
            return data;
        } catch (IOException e) {
        }
        return "";
    }

    public String getPinStatus() {
        try {
            BufferedReader reader = new BufferedReader(new FileReader(getStatusURI()));
            String data = reader.readLine();
            reader.close();
            return data;
        } catch (IOException e) {
        }
        return "";
    }

    private void writeToFile(String URI, String data) {
        try {
            File file = new File(URI);
            file.delete();
            File newFile = new File(URI);
            newFile.createNewFile();
            FileWriter writer = new FileWriter(URI);
            writer.write(data);
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Next, create test class,code as follows:
package com.test;

public class Test {
    public static void main(String[] args) throws Interrupted Exception {
        GPIO_Pin ledpin=new GPIO_Pin(1);
        ledpin.setModeOUTPUT();
        while (true) {
            ledpin.setHIGH();
            Thread.sleep(400);
            ledpin.setLOW();
            Thread.sleep(400);
        }
    }
}

[/vc_column_text][/vc_tab][vc_tab title=”Test result” tab_id=”1393684350346-3-6″][vc_column_text]The LED keep flashing after the program started.

[/vc_column_text][/vc_tab][vc_tab title=”The source program” tab_id=”1393684360004-4-9″][vc_column_text]Download the source program :  Java control the GPIO pin   Lamp  [/vc_column_text][/vc_tab][/vc_tour][/vc_column][/vc_row]