我对jSSC的写入功能有问题。我的Arduino Uno板似乎没有从我的Java程序中获取数据。
我有一个由Arduino Uno板控制的步进电机。我做了一个有两个按钮的简单程序。一种是顺时针旋转，另一种是逆时针旋转。CW按钮发送"H"字符，CCW按钮发送"L"字符。现在我有：
- 我从Arduino IDE串行控制台检查了我的Arduino程序是否正常工作。当我发送"H"时，电机顺时针转动，发送"L"时，发动机逆时针转动
- 我在Processing中制作了一个程序，其中有两个按钮发送"H"one_answers"L"。它奏效了
- 我用JSSC制作了一个Java程序，其中有两个按钮发送"H"one_answers"L"。它失败了。当我按下程序中的一个按钮时，我看到板上的"L"灯闪烁3-4次，但什么也没发生
- 我试着用JSSC从我的董事会获取数据，结果成功了。问题似乎出在书写功能上
- 我检查了另一个Arduino Uno董事会，但结果是一样的
我的Java程序使用serialPort.writeByte((byte)'H');和serialPort.writeByte((byte)'L');
有什么想法吗？
是否尝试设置流量控制的参数。因为在写入接口时，它需要权限。
serialPort.setParams(SerialPort.BAUDRATE_9600,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE,false,true);//Set params. Also you can set params by this string: serialPort.setParams(9600, 8, 1, 0,RTSEnable,DTSEnable);
serialPort.setFlowControlMode(SerialPort.FLOWCONTROL_NONE);
这可能是与重置相关的问题吗？也许您的java函数使用DTR引脚，该引脚连接到RESET引脚；因此，当你试图发送数据时，你只是在重置电路板。
如果你想测试，你可以在启动时让另一个led闪烁，或者在设置时通过串行接口发送一些东西。如果你得到了反馈，试着看看禁用DTR的方法；）
如果您不打算在java项目中使用它，您可以重构Processing的Serial类（工作得很好）以避免PApplet：
/*
PSerial - class for serial port goodness
Part of the Processing project - http://processing.org
Copyright (c) 2004-05 Ben Fry & Casey Reas
Reworked by Gottfried Haider as part of GSOC 2013
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General
Public License along with this library; if not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330,
Boston, MA 02111-1307 USA
*/
import java.lang.reflect.Method;
import java.util.Map;
import jssc.SerialPort;
import jssc.SerialPortEvent;
import jssc.SerialPortEventListener;
import jssc.SerialPortException;
import jssc.SerialPortList;
public class Serial implements SerialPortEventListener {
Object parent;
public SerialPort port;
Method serialAvailableMethod;
Method serialEventMethod;
byte[] buffer = new byte[32768];
int inBuffer = 0;
int readOffset = 0;
int bufferUntilSize = 1;
byte bufferUntilByte = 0;
volatile boolean invokeSerialAvailable = false;
// Things we are currently not exposing:
// * hardware flow control
// * state of the RING, RLSD line
// * sending breaks
public Serial(Object parent) {
this(parent, "COM1", 9600, 'N', 8, 1);
}
public Serial(Object parent, int baudRate) {
this(parent, "COM1", baudRate, 'N', 8, 1);
}
public Serial(Object parent, String portName) {
this(parent, portName, 9600, 'N', 8, 1);
}
public Serial(Object parent, String portName, int baudRate) {
this(parent, portName, baudRate, 'N', 8, 1);
}
public Serial(Object parent, String portName, int baudRate, char parity, int dataBits, float stopBits) {
this.parent = parent;
//parent.registerMethod("dispose", this);
//parent.registerMethod("pre", this);
// setup parity
if (parity == 'O') {
parity = SerialPort.PARITY_ODD;
} else if (parity == 'E') {
parity = SerialPort.PARITY_EVEN;
} else if (parity == 'M') {
parity = SerialPort.PARITY_MARK;
} else if (parity == 'S') {
parity = SerialPort.PARITY_SPACE;
} else {
parity = SerialPort.PARITY_NONE;
}
// setup stop bits
int stopBitsIdx = SerialPort.STOPBITS_1;
if (stopBits == 1.5f) {
stopBitsIdx = SerialPort.STOPBITS_1_5;
} else if (stopBits == 2) {
stopBitsIdx = SerialPort.STOPBITS_2;
}
port = new SerialPort(portName);
try {
// the native open() call is not using O_NONBLOCK, so this might block for certain operations (see write())
port.openPort();
port.setParams(baudRate, dataBits, stopBitsIdx, parity);
// we could register more events here
port.addEventListener(this, SerialPort.MASK_RXCHAR);
} catch (SerialPortException e) {
// this used to be a RuntimeException before, so stick with it
throw new RuntimeException("Error opening serial port " + e.getPortName() + ": " + e.getExceptionType());
}
serialEventMethod = findCallback("serialEvent");
serialAvailableMethod = findCallback("serialAvailable");
}
private Method findCallback(final String name) {
try {
return parent.getClass().getMethod(name, this.getClass());
} catch (Exception e) {
}
// Permit callback(Object) as alternative to callback(Serial).
try {
return parent.getClass().getMethod(name, Object.class);
} catch (Exception e) {
}
return null;
}
public void dispose() {
stop();
}
public void pre() {
if (serialAvailableMethod != null && invokeSerialAvailable) {
invokeSerialAvailable = false;
try {
serialAvailableMethod.invoke(parent, this);
} catch (Exception e) {
System.err.println("Error, disabling serialAvailable() for "+port.getPortName());
System.err.println(e.getLocalizedMessage());
serialAvailableMethod = null;
}
}
}
public int available() {
return (inBuffer-readOffset);
}
public void buffer(int size) {
bufferUntilSize = size;
}
public void bufferUntil(int inByte) {
bufferUntilSize = 0;
bufferUntilByte = (byte)inByte;
}
public void clear() {
synchronized (buffer) {
inBuffer = 0;
readOffset = 0;
}
}
public boolean getCTS() {
try {
return port.isCTS();
} catch (SerialPortException e) {
throw new RuntimeException("Error reading the CTS line: " + e.getExceptionType());
}
}
public boolean getDSR() {
try {
return port.isDSR();
} catch (SerialPortException e) {
throw new RuntimeException("Error reading the DSR line: " + e.getExceptionType());
}
}
public static Map<String, String> getProperties(String portName) {
return SerialPortList.getPortProperties(portName);
}
public int last() {
if (inBuffer == readOffset) {
return -1;
}
synchronized (buffer) {
int ret = buffer[inBuffer-1] & 0xFF;
inBuffer = 0;
readOffset = 0;
return ret;
}
}
public char lastChar() {
return (char)last();
}
public static String[] list() {
// returns list sorted alphabetically, thus cu.* comes before tty.*
// this was different with RXTX
return SerialPortList.getPortNames();
}
public int read() {
if (inBuffer == readOffset) {
return -1;
}
synchronized (buffer) {
int ret = buffer[readOffset++] & 0xFF;
if (inBuffer == readOffset) {
inBuffer = 0;
readOffset = 0;
}
return ret;
}
}
public byte[] readBytes() {
if (inBuffer == readOffset) {
return null;
}
synchronized (buffer) {
byte[] ret = new byte[inBuffer-readOffset];
System.arraycopy(buffer, readOffset, ret, 0, ret.length);
inBuffer = 0;
readOffset = 0;
return ret;
}
}
public int readBytes(byte[] dest) {
if (inBuffer == readOffset) {
return 0;
}
synchronized (buffer) {
int toCopy = inBuffer-readOffset;
if (dest.length < toCopy) {
toCopy = dest.length;
}
System.arraycopy(buffer, readOffset, dest, 0, toCopy);
readOffset += toCopy;
if (inBuffer == readOffset) {
inBuffer = 0;
readOffset = 0;
}
return toCopy;
}
}
public byte[] readBytesUntil(int inByte) {
if (inBuffer == readOffset) {
return null;
}
synchronized (buffer) {
// look for needle in buffer
int found = -1;
for (int i=readOffset; i < inBuffer; i++) {
if (buffer[i] == (byte)inByte) {
found = i;
break;
}
}
if (found == -1) {
return null;
}
int toCopy = found-readOffset+1;
byte[] dest = new byte[toCopy];
System.arraycopy(buffer, readOffset, dest, 0, toCopy);
readOffset += toCopy;
if (inBuffer == readOffset) {
inBuffer = 0;
readOffset = 0;
}
return dest;
}
}
public int readBytesUntil(int inByte, byte[] dest) {
if (inBuffer == readOffset) {
return 0;
}
synchronized (buffer) {
// look for needle in buffer
int found = -1;
for (int i=readOffset; i < inBuffer; i++) {
if (buffer[i] == (byte)inByte) {
found = i;
break;
}
}
if (found == -1) {
return 0;
}
// check if bytes to copy fit in dest
int toCopy = found-readOffset+1;
if (dest.length < toCopy) {
System.err.println( "The buffer passed to readBytesUntil() is to small " +
"to contain " + toCopy + " bytes up to and including " +
"char " + (byte)inByte);
return -1;
}
System.arraycopy(buffer, readOffset, dest, 0, toCopy);
readOffset += toCopy;
if (inBuffer == readOffset) {
inBuffer = 0;
readOffset = 0;
}
return toCopy;
}
}
public char readChar() {
return (char) read();
}
public String readString() {
if (inBuffer == readOffset) {
return null;
}
return new String(readBytes());
}
public String readStringUntil(int inByte) {
byte temp[] = readBytesUntil(inByte);
if (temp == null) {
return null;
} else {
return new String(temp);
}
}
public void serialEvent(SerialPortEvent event) {
if (event.getEventType() == SerialPortEvent.RXCHAR) {
int toRead;
try {
while (0 < (toRead = port.getInputBufferBytesCount())) {
// this method can be called from the context of another thread
synchronized (buffer) {
// read one byte at a time if the sketch is using serialEvent
if (serialEventMethod != null) {
toRead = 1;
}
// enlarge buffer if necessary
if (buffer.length < inBuffer+toRead) {
byte temp[] = new byte[buffer.length<<1];
System.arraycopy(buffer, 0, temp, 0, inBuffer);
buffer = temp;
}
// read an array of bytes and copy it into our buffer
byte[] read = port.readBytes(toRead);
System.arraycopy(read, 0, buffer, inBuffer, read.length);
inBuffer += read.length;
}
if (serialEventMethod != null) {
if ((0 < bufferUntilSize && bufferUntilSize <= inBuffer-readOffset) ||
(0 == bufferUntilSize && bufferUntilByte == buffer[inBuffer-1])) {
try {
// serialEvent() is invoked in the context of the current (serial) thread
// which means that serialization and atomic variables need to be used to
// guarantee reliable operation (and better not draw() etc..)
// serialAvailable() does not provide any real benefits over using
// available() and read() inside draw - but this function has no
// thread-safety issues since it's being invoked during pre in the context
// of the Processing applet
serialEventMethod.invoke(parent, this);
} catch (Exception e) {
System.err.println("Error, disabling serialEvent() for "+port.getPortName());
System.err.println(e.getLocalizedMessage());
serialEventMethod = null;
}
}
}
invokeSerialAvailable = true;
}
} catch (SerialPortException e) {
throw new RuntimeException("Error reading from serial port " + e.getPortName() + ": " + e.getExceptionType());
}
}
}
public void setDTR(boolean state) {
// there is no way to influence the behavior of the DTR line when opening the serial port
// this means that at least on Linux and OS X, Arduino devices are always reset
try {
port.setDTR(state);
} catch (SerialPortException e) {
throw new RuntimeException("Error setting the DTR line: " + e.getExceptionType());
}
}
public void setRTS(boolean state) {
try {
port.setRTS(state);
} catch (SerialPortException e) {
throw new RuntimeException("Error setting the RTS line: " + e.getExceptionType());
}
}
public void stop() {
try {
port.closePort();
} catch (SerialPortException e) {
// ignored
}
inBuffer = 0;
readOffset = 0;
}
public void write(byte[] src) {
try {
// this might block if the serial device is not yet ready (esp. tty devices under OS X)
port.writeBytes(src);
// we used to call flush() here
} catch (SerialPortException e) {
throw new RuntimeException("Error writing to serial port " + e.getPortName() + ": " + e.getExceptionType());
}
}
public void write(int src) {
try {
port.writeInt(src);
} catch (SerialPortException e) {
throw new RuntimeException("Error writing to serial port " + e.getPortName() + ": " + e.getExceptionType());
}
}
public void write(String src) {
try {
port.writeString(src);
} catch (SerialPortException e) {
throw new RuntimeException("Error writing to serial port " + e.getPortName() + ": " + e.getExceptionType());
}
}
}
下面是一个使用上面内容的示例类：
public class SerialTest {
public static void main(String[] args) {
try{
Serial serial = new Serial(new SerialTest(),"/dev/tty.usbmodemfd121",115200);
serial.write("H");
serial.write("L");//can also try serial.write((int)'L');
}catch(Exception e){
System.err.println("serial not connected!");
}
}
public void serialAvailable(Serial s){
System.out.println(s.toString());
}
public void serialEvent(Serial s){
System.out.print("from serial:");
System.out.println(s.read());
}
}
请确保将端口和波特率更改为Arduino Uno正在使用的端口和波特率。
在Processing的串行库文件夹中，您还可以找到JNI本机库。例如在Windows:上
C:Program Filesprocessing-2.1.2modesjavalibrariesseriallibrary
dll在windows32和windows64文件夹中的位置，具体取决于您计划使用的内容。上面的Serial类与C:Program Filesprocessing-2.1.2modesjavalibrariesserialsrcprocessingserial/Serial.java用Object替换PApplet非常相似。
此外，这里还有处理串行库参考