Ubuntu RXTX 无法识别 USB 串行设备 [英] Ubuntu RXTX does not recognize usb-serial device
问题描述
我正在将带有 librxtx-java 的设备连接到 Ubuntu.该代码以前在 10.04 中有效，但在 12.04 中无法发现连接到计算机的 USB 串口.
I'm connecting a device with librxtx-java to Ubuntu. The code previously worked in 10.04, but in 12.04 it can't discover the usb-serial connected to the computer.
java.util.Enumeration<CommPortIdentifier> portEnum = CommPortIdentifier.getPortIdentifiers();
while ( portEnum.hasMoreElements() )
{
CommPortIdentifier portIdentifier = portEnum.nextElement();
System.out.println( portIdentifier.getName() + " - " + getPortTypeName(portIdentifier.getPortType()) );
}
尽管安装了适当的 librxtx-java 库，并且设备被识别(dmesg | tail 在一行上显示 USB检测到串行设备转换器")，这部分代码永远不会进入 while 循环.
This section of the code never goes into the while loop, despite the appropriate librxtx-java libraries being installed, and device being recognized (dmesg | tail shows USB "Serial Device converter detected" on one line).
更新:
看来 64 位 Ubuntu 12.04 不能与任何 USB 串行设备一起使用(尽管它们出现在 dmesg 中并显示为/dev/ttyUSB，但这似乎不仅仅是 Java 的问题.
It appears Ubuntu 12.04 64-bit isn't working with any usb-serial devices (although they show up in dmesg and show up as a /dev/ttyUSB, it seems to be more than just a problem with Java.
推荐答案
我有 Ubuntu 11.10 内核 3.0.0-12-generic-pae 和 librxtx-java 版本 2.2pre2-8 安装.使用下面的代码，它正确列出了我的串行端口.现在您已经正确安装了 USB 转串口转换器吗?您需要检查转换器使用的是哪个端口.使用下面的示例应用程序，您可以尝试类似 java -cp/usr/share/java/RXTXcomm.jar: 的内容.获取通信端口 2
I have Ubuntu 11.10 kernel 3.0.0-12-generic-pae and librxtx-java version 2.2pre2-8 installed. With the code below, it list my serial ports correctly. Now you have usb to serial converter installed properly? you need to check that what port is the converter use. Using the sample app below, you can try something like java -cp /usr/share/java/RXTXcomm.jar:. GetCommPorts 2
请确保您在/dev/中的 ttySXX 或 ttyUSBXX 文件中拥有正确的权限.
Please ensure that you have the correct permission in the ttySXX or ttyUSBXX file, in /dev/.
crw-rw---- 1 root dialout 4, 65 2012-02-29 01:08 /dev/ttyS1
crw-rw---- 1 root dialout 4, 66 2012-02-29 01:08 /dev/ttyS2
这些串口显示在我的系统中，想要运行应用程序的用户应该在组拨出下.要添加自己，请使用:
These serial ports are shown in my system and the user who want to run the application should be under group dialout. To add yourself, use:
sudo usermod -a -G dialout username
您现在应该在拨出"组中.
You should now be in "dialout" group.
import gnu.io.CommPortIdentifier;
import gnu.io.NoSuchPortException;
import gnu.io.PortInUseException;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import gnu.io.UnsupportedCommOperationException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.TooManyListenersException;
public class GetCommPorts
{
static Enumeration<CommPortIdentifier> portList;
static CommPortIdentifier portId;
static SerialPort serialPort;
static OutputStream outputStream;
static boolean outputBufferEmptyFlag = false;
public static class SerialReader implements SerialPortEventListener
{
private InputStream in;
private byte[] buffer = new byte[1024];
public SerialReader(InputStream in)
{
this.in = in;
}
@Override
/**
* treat \n as end of block.
*/
public void serialEvent(SerialPortEvent ev)
{
int data;
try
{
int len = 0;
while ( (data = in.read()) > -1)
{
if (data == '\n')
{
break;
}
buffer[len++] = (byte) data;
}
System.out.println(new String(buffer, 0, len));
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
System.exit(-1);
}
}
}
public static class SerialWriter implements Runnable
{
OutputStream out;
public SerialWriter(OutputStream out)
{
this.out = out;
}
@Override
public void run()
{
try
{
int c = 0;
while ( (c = System.in.read()) > -1)
{
this.out.write(c);
}
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
System.exit(-1);
}
}
}
private static String getPortTypeName ( int portType )
{
switch ( portType )
{
case CommPortIdentifier.PORT_I2C:
return "I2C";
case CommPortIdentifier.PORT_PARALLEL:
return "Parallel";
case CommPortIdentifier.PORT_RAW:
return "Raw";
case CommPortIdentifier.PORT_RS485:
return "RS485";
case CommPortIdentifier.PORT_SERIAL:
return "Serial";
default:
return "unknown type";
}
}
private static void listPorts()
{
@SuppressWarnings("unchecked")
java.util.Enumeration<CommPortIdentifier> portEnum = CommPortIdentifier.getPortIdentifiers();
while ( portEnum.hasMoreElements() )
{
CommPortIdentifier portIdentifier = portEnum.nextElement();
System.out.println(portIdentifier.getName() + " - " + getPortTypeName(portIdentifier.getPortType()) );
if (portIdentifier.getPortType() == 1)
{
try
{
serialPort = (SerialPort) portIdentifier.open(portIdentifier.getName(), 3000);
}
catch (PortInUseException e)
{
System.err.print("port in use");
continue;
}
System.out.println("Baud is " + serialPort.getBaudRate());
System.out.println("Bits is " + serialPort.getDataBits());
System.out.println("Stop is " + serialPort.getStopBits());
System.out.println("Par is " + serialPort.getParity());
serialPort.close();
}
}
}
private static int doReadWrite(String portName)
{
CommPortIdentifier portIdentifier;
try
{
portIdentifier = CommPortIdentifier.getPortIdentifier(portName);
if (portIdentifier.isCurrentlyOwned())
{
System.err.println("error: port is currently in use");
return -1;
}
SerialPort sport = (SerialPort) portIdentifier.open(portName, 3000);
sport.setSerialPortParams(57600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
InputStream in = sport.getInputStream();
OutputStream out = sport.getOutputStream();
(new Thread(new SerialWriter(out))).start();
sport.addEventListener(new SerialReader(in));
sport.notifyOnDataAvailable(true);
}
catch (NoSuchPortException e)
{
e.printStackTrace();
return -1;
}
catch (PortInUseException e)
{
e.printStackTrace();
return -1;
}
catch (UnsupportedCommOperationException e)
{
e.printStackTrace();
return -1;
}
catch (IOException e)
{
e.printStackTrace();
return -1;
}
catch (TooManyListenersException e)
{
e.printStackTrace();
return -1;
}
return 0;
}
static void showHelp()
{
System.out.println("Usage " + GetCommPorts.class.getName() + "N");
System.out.println("1 read and write from the serial port");
System.out.println("2 list all serial ports in the system");
System.out.println("default show this help ");
}
public static void main(String[] args)
{
int operation = 0;
try
{
if (args.length != 1)
{
showHelp();
return;
}
operation = Integer.parseInt(args[0]);
}
catch (NumberFormatException e)
{
}
switch (operation)
{
case 1:
doReadWrite("/dev/ttyUSB0");
break;
case 2:
listPorts();
break;
default:
showHelp();
}
}
}
此应用程序的输出:
$ java -cp /usr/share/java/RXTXcomm.jar:. GetCommPorts 2
/dev/ttyS1 - Serial
Baud is 9600
Bits is 8
Stop is 1
Par is 0
/dev/ttyS0 - Serial
Baud is 9600
Bits is 8
Stop is 1
Par is 0
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