在Java中处理Arduino串行输入10秒+延迟

Question

我想做什么： 从我的Arduino（COM3）读取Serial.println，没有及时延迟

我的情况是： 此Java程序在串行输入中延迟大约20秒。

这是通过Arduino IDE串行监视器实现的。我想将串行监视器代码嵌入到我的Java应用程序中。

下面附上有用的代码（该程序应该在接收Serial的计算机上运行。）：

package arduino;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import gnu.io.CommPortIdentifier; 
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent; 
import gnu.io.SerialPortEventListener; 
import java.util.Enumeration;


public class SerialTest implements SerialPortEventListener {
    SerialPort serialPort;
    /** The port we're normally going to use. */
    private static final String PORT_NAMES[] = {"COM3"};
    /**
    * A BufferedReader which will be fed by a InputStreamReader 
    * converting the bytes into characters 
    * making the displayed results codepage independent
    */
    private BufferedReader input;
    /** The output stream to the port */
    private OutputStream output;
    /** Milliseconds to block while waiting for port open */
    private static final int TIME_OUT = 2000;
    /** Default bits per second for COM port. */
    private static final int DATA_RATE = 50000;

    public void initialize() {
                // the next line is for Raspberry Pi and 
                // gets us into the while loop and was suggested here was     suggested http://www.raspberrypi.org/phpBB3/viewtopic.php?f=81&t=32186
            //System.setProperty("gnu.io.rxtx.SerialPorts", "/dev/ttyACM0");

        CommPortIdentifier portId = null;
        Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();

        //First, Find an instance of serial port as set in PORT_NAMES.
        while (portEnum.hasMoreElements()) {
            CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
            for (String portName : PORT_NAMES) {
            if (currPortId.getName().equals(portName)) {
                portId = currPortId;
                break;
            }
        }
    }
    if (portId == null) {
        System.out.println("Could not find COM port.");
        return;
    }

    try {
        // open serial port, and use class name for the appName.
        serialPort = (SerialPort) portId.open(this.getClass().getName(),
                TIME_OUT);

        // set port parameters
        serialPort.setSerialPortParams(DATA_RATE,
                SerialPort.DATABITS_8,
                SerialPort.STOPBITS_1,
                SerialPort.PARITY_NONE);

        // open the streams
        input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
        output = serialPort.getOutputStream();

        // add event listeners
        serialPort.addEventListener(this);
        serialPort.notifyOnDataAvailable(true);
    } catch (Exception e) {
        System.err.println(e.toString());
    }
}

/**
 * This should be called when you stop using the port.
 * This will prevent port locking on platforms like Linux.
 */
public synchronized void close() {
    if (serialPort != null) {
        serialPort.removeEventListener();
        serialPort.close();
    }
}

/**
 * Handle an event on the serial port. Read the data and print it.
 */
public synchronized void serialEvent(SerialPortEvent oEvent) {
    if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
        try {
            String inputLine=null;
            if (input.ready()) {
                inputLine = input.readLine();
                            System.out.println(inputLine);
            }

        } catch (Exception e) {
            System.err.println(e.toString());
        }
    }
    // Ignore all the other eventTypes, but you should consider the other ones.
}

public static void main(String[] args) throws Exception {
    SerialTest main = new SerialTest();
    main.initialize();
    Thread t=new Thread() {
        public void run() {
            //the following line will keep this app alive for 1000 seconds,
            //waiting for events to occur and responding to them (printing incoming messages to console).
            try {Thread.sleep(1000000);} catch (InterruptedException ie) {}
        }
    };
    t.start();
    System.out.println("Started");
}
}

以下附加有用的代码应该在Arduino上运行，涉及使用街机游戏杆。我在串口监视器中没有遇到任何问题进行了测试，只是想我会将其附加在其中。

/*
The Joystick Adapter to Snake Display 

Joystick connected to DIGITAL port 5 - 2

*/

//Define pins
const int joyA = 5;
const int joyB = 4;
const int joyC = 3;
const int joyD = 2;



//Begin.
void setup(){
  pinMode(joyA,INPUT);
  pinMode(joyB,INPUT);
  pinMode(joyC,INPUT);
  pinMode(joyD,INPUT);
  Serial.begin(9600);
}


void loop(){
  boolean a = isaxisPressed(joyA);
  boolean b = isaxisPressed(joyB);
  boolean c = isaxisPressed(joyC);
  boolean d = isaxisPressed(joyD);
  if(a){
    Serial.println("A");
  }else if(b){
    Serial.println("B");
  }else if(c){
    Serial.println("C");
  }else if(d){
    Serial.println("D");
  }else{
    Serial.println("Z");
  }
}

boolean isaxisPressed(int port){
  pinMode(port,OUTPUT);
  digitalWrite(port,HIGH);
  pinMode(port,INPUT);
  return !digitalRead(port);
}