I am developing program which need to interact with COM ports.
By learning from this Q&A: .NET SerialPort DataReceived event not firing, I make my code like that.
namespace ConsoleApplication1
{
class Program
{
static SerialPort ComPort;
public static void OnSerialDataReceived(object sender, SerialDataReceivedEventArgs args)
{
string data = ComPort.ReadExisting();
Console.Write(data.Replace("\r", "\n"));
}
static void Main(string[] args)
{
string port = "COM4";
int baud = 9600;
if (args.Length >= 1)
{
port = args[0];
}
if (args.Length >= 2)
{
baud = int.Parse(args[1]);
}
InitializeComPort(port, baud);
string text;
do
{
String[] mystring = System.IO.Ports.SerialPort.GetPortNames();
text = Console.ReadLine();
int STX = 0x2;
int ETX = 0x3;
ComPort.Write(Char.ConvertFromUtf32(STX) + text + Char.ConvertFromUtf32(ETX));
} while (text.ToLower() != "q");
}
private static void InitializeComPort(string port, int baud)
{
ComPort = new SerialPort(port, baud);
ComPort.PortName = port;
ComPort.BaudRate = baud;
ComPort.Parity = Parity.None;
ComPort.StopBits = StopBits.One;
ComPort.DataBits = 8;
ComPort.ReceivedBytesThreshold = 9;
ComPort.RtsEnable = true;
ComPort.DtrEnable = true;
ComPort.Handshake = System.IO.Ports.Handshake.XOnXOff;
ComPort.DataReceived += OnSerialDataReceived;
OpenPort(ComPort);
}
public static void OpenPort(SerialPort ComPort)
{
try
{
if (!ComPort.IsOpen)
{
ComPort.Open();
}
}
catch (Exception e)
{
throw e;
}
}
}
}
My problem is DataReceived event never gets fired.
My program specifications are:
Just .net console programming
I use VSPE from http://www.eterlogic.com
My computer has COM1 and COM2 ports already.
I created COM2 and COM4 by using VSPE.
I get output result from mystring array (COM1, COM2, COM3, COM4)
But I still don't know why DataReceived event is not fired.
Updated
Unfortunately, I still could not make to fire DataReceived event in any way.
So, I created new project by hoping that I will face a way to solve.
At that new project [just console application], I created a class...
public class MyTest
{
public SerialPort SPCOM4;
public MyTest()
{
SPCOM4 = new SerialPort();
if(this.SerialPortOpen(SPCOM4, "4"))
{
this.SendToPort(SPCOM4, "com test...");
}
}
private bool SerialPortOpen(System.IO.Ports.SerialPort objCom, string portName)
{
bool blnOpenStatus = false;
try
{
objCom.PortName = "COM" + portName;
objCom.BaudRate = 9600;
objCom.DataBits = 8;
int SerParity = 2;
int SerStop = 0;
switch (SerParity)
{
case 0:
objCom.Parity = System.IO.Ports.Parity.Even;
break;
case 1:
objCom.Parity = System.IO.Ports.Parity.Odd;
break;
case 2:
objCom.Parity = System.IO.Ports.Parity.None;
break;
case 3:
objCom.Parity = System.IO.Ports.Parity.Mark;
break;
}
switch (SerStop)
{
case 0:
objCom.StopBits = System.IO.Ports.StopBits.One;
break;
case 1:
objCom.StopBits = System.IO.Ports.StopBits.Two;
break;
}
objCom.RtsEnable = false;
objCom.DtrEnable = false;
objCom.Handshake = System.IO.Ports.Handshake.XOnXOff;
objCom.Open();
blnOpenStatus = true;
}
catch (Exception ex)
{
throw ex;
}
return blnOpenStatus;
}
private bool SendToPort(System.IO.Ports.SerialPort objCom, string strText)
{
try
{
int STX = 0x2;
int ETX = 0x3;
if (objCom.IsOpen && strText != "")
{
objCom.Write(Char.ConvertFromUtf32(STX) + strText + Char.ConvertFromUtf32(ETX));
}
}
catch (Exception ex)
{
throw ex;
}
return true;
}
}
I am not sure that I face good luck or bad luck because this new class could make fire DataReceived event which is from older console application that is still running. It is miracle to me which I have no idea how this happen.
Let me tell you more detail so that you could give me suggestion for better way.
Finally I created 2 console projects.
First project is the class which I posted as a question yesterday.
Second project is the class called MyTest which could make fire DataReceived event from First project, at the same time when two of the project is running.
Could anyone give me suggestions on how could I combine these two projects as a single project?
ComPort.Handshake = Handshake.None;
The problem is not that the DataReceived event doesn't fire, the problem is that the serial port isn't receiving any data. There are very, very few serial devices that use no handshaking at all. If you set it to None then the driver won't turn on the DTR (Data Terminal Ready) and RTS (Request To Send) signals. Which a serial port device interprets as "the machine is turned off (DTR)" or "the machine isn't ready to receive data (RTS)". So it won't send anything and your DataReceived event won't fire.
If you really want None then set the DTREnable and RTSEnable properties to true. But it is likely you want HandShake.RequestToSend since the device appears to be paying attention to the handshake signals.
If you still have trouble then use another serial port program like Putty or HyperTerminal to ensure the connection and communication parameters are good and the device is responsive. SysInternals' PortMon utility gives a low-level view of the driver interaction so you can compare good vs bad.
I have never worked with VSPE so I'm not sure if that causes the problem. I have worked with a COM port before and I looked up my code. The only main difference is the way you declare the event. You have:
ComPort.DataReceived += OnSerialDataReceived;
I have it like this:
ComPort.DataReceived += new SerialDataReceivedEventHandler(OnSerialDataReceived);
OnSerialDataReceived is your eventhandler. I'm not sure if this will make any difference, but you can try it. I hope this helps!
I had a quite similar problem. In a graphical application (C# win form) I had a class which encapsulate a SerialPort component. The DataReceived event was firing only one time, but then any following data received didn't fire any event. I solved the problem by calling the Close method in my principal form Closed event function.
No idea of why that changes anything, but now it's working.
Related
I am using .net 4.5 and since i got aware about some internet discussion about .net having wrong code implementation to rad serial data, i went with the code below.
The problems is however even despite i can see i create a COM port connection (to the right com port number), its never firing on data received.
The data receiving is based upon a simple Arduino app, (Arduino monitor does show data gets send over serial), but .net never seams to fire upon serial events.
I've put breakpoints on eventread, it never gets hit
i've looked at other discussions here like .NET SerialPort DataReceived event not firing but so far they don't resolve the issue i have. I tried various combination of serial line setups, and believe the below ones are correct.
as for Arduino part the line is setup as:
Serial.begin(9600);
I call my class like : `InfraredSensor mySens = new InfraredSensor("COM4",9600);'
class InfraredSensor
{
private string Eventlogapp = "IRlogging";
private SerialPort Port;
public InfraredSensor(string COMport, int baudrate) //constructor
{
if (applicationlog != "") this.EventlogSapec = applicationlog;
WriteEventLog(EventlogSapec, EventSource, "Initializing-IR:" + COMport, info, EventIRStarted);
// I found that the .net standard implementation for com port reading is not OK (.net doesnt follow win32 api).
// There are numerous readings about it, but a good way to read seams to be to use Serial BaseStream.ReadAsync
// code below is based upon : http://www.c-sharpcorner.com/code/2880/serial-port-with-efficient-data-reading-in-c-sharp.aspx
this.comport = COMport;
SerialPort Port = new SerialPort(comport);
Port.BaudRate = baudrate;
Port.DataBits = 8;
Port.Parity = Parity.None;
Port.StopBits = StopBits.One;
Port.Handshake = Handshake.None;
Port.NewLine = Environment.NewLine;
Port.ReceivedBytesThreshold = 2; // + linefeed
Port.DataReceived += ReadEvent;
Port.Open();
Port.DtrEnable = true;
// i've tested from here i do have an open connection
// its just dat ReadEvent never fires...
}
private void ReadEvent(object sender, SerialDataReceivedEventArgs e)
{
byte[] buffer = new byte[2];//todo i only send "A" or "B", for the debug moment
Action kickoffRead = null;
kickoffRead = (Action)(() => Port.BaseStream.BeginRead(buffer, 0, buffer.Length, delegate (IAsyncResult ar)
{
try
{
int count = Port.BaseStream.EndRead(ar);
byte[] dst = new byte[count];
Buffer.BlockCopy(buffer, 0, dst, 0, count);
RaiseAppSerialDataEvent(dst);
}
catch (Exception ex)
{
WriteEventLog(Eventlogapp, "IR", "Failure-IR:" + ex.Message, info, 204);
}
kickoffRead();
}, null)); kickoffRead();
}
private void RaiseAppSerialDataEvent(byte[] Data)
{
// code never gets to here
string msg = Encoding.Default.GetString(Data);
int breakpointhere = 0;
if (msg.Contains('A')) WriteEventLog(Eventlogapp, "IR", "Sensor A", info, 213);
if (msg.Contains('B')) WriteEventLog(Eventlogapp, "IR", "Sensor B", info, 214);
}
}
I ran out of ideas (and hair as its driving me nuts) what could cause this behaviour ?
finally this took me 2 days ...
in arduino code i now use
serial.print("Mytext\n"); // using \n to be sure of escape character
for the serial line config i now use
this.comport = COMport;
this.Port = new SerialPort(comport);
this.Port.BaudRate = baudrate;
this.Port.DataBits = 8;
this.Port.Parity = Parity.None;
this.Port.StopBits = StopBits.One;
this.Port.Handshake = Handshake.None;
this.Port.RtsEnable = true;
// Port.NewLine = "\n";
// Port.ReceivedBytesThreshold = 2; // + linefeed
this.Port.DataReceived += new new SerialDataReceivedEventHandler(ReadEvent);
....
..
SerialDataReceivedEventHandler(ReadEvent);
//code didnt change inside but the method has changed see the +=
The DataReceived event fires when there is data coming through the serial port, but it can fire randomly. So you could get part of the message in one event and the other half of the message in another event. You should have some sort of key to know when you have the whole message. So build your string until you have the whole message then do something based on the message.
For example, my device's message is done when there is a Line Feed. So my code looks something like:
char ESC = (char)27;
char CR = (char)13;
char LF = (char)10;
StringBuilder sb = new StringBuilder();
private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
string Data = serialPort1.ReadExisting();
foreach (char c in Data)
{
if (c == LF)
{
sb.Append(c);
//we have our message, do something, maybe like
if (sb.ToString().Contains("A"))
{
//print A
}
else
{
//print B
}
}
else
{
sb.Append(c);
}
}
}
So I have this port that I'm opening and saving the name of the port in a setting of my application. When I load the form it tries to open the port however fails to do so. Only after clicking on my "open port" button that has the EXACT same code does the port open. And then If I click my "close port" button and reopen the form it works! It automatically opens the port for me. However it's only if I'm fast enough. If I leave the application closed (and thus port closed) for say 10-15 seconds and reopen the application, I'll get my error thrown at me. What's the reason for this??
The code used at launch and in my "open port" button:
mySerialPort.createPort(Properties.Settings.Default.portName);
if (!mySerialPort.isOpen)
{
try
{
mySerialPort.openSerialPort();
}
catch
{
MessageBox.Show("Error: Could not open Serial port " + Properties.Settings.Default.portName, "Port Opening Failed", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
if (mySerialPort.isOpen)
{
portActiveStatusLbl.Text = Properties.Settings.Default.portName + " OPEN";
portActiveStatusLbl.ForeColor = Color.Green;
}
}
and here's mySerialPort Class:
public static class SerialPortConfig
{
public static SerialPort mySerialPort = new SerialPort();
public static string myString = "";
public static bool isOpen { get { return mySerialPort.IsOpen; } }
public static void createPort (string portName)
{
if (portName == "")
portName = "COM1";
mySerialPort.PortName = portName;
mySerialPort.BaudRate = 2400; //Depending on the hardware used this may change, mitutoyo input tool asks for 2400 baud
mySerialPort.Parity = Parity.None;
mySerialPort.StopBits = StopBits.One;
mySerialPort.DataBits = 8;
mySerialPort.Handshake = Handshake.RequestToSend; //DO NOT SET TO NONE
mySerialPort.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);
}
public static void openSerialPort()
{
mySerialPort.Open();
}
public static void closeSerialPort()
{
mySerialPort.Close();
}
private static void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
SerialPort sp = (SerialPort)sender;
string indata = sp.ReadExisting(); //stores the char that fired the event into 'indata'
myString += indata;
if (indata.Contains("\r")) //check to see if char received indicates end of measurement
{
if (myString == "911\r") //911 is the code given when the micrometer is off, so we have it do nothing
myString = "";
else
{
myString = myString.Substring(4, 8);
Form1.instance.pendingMeasurement = true;
}
}
}
}
I am developing program which need to interact with COM ports.
By learning from this Q&A: .NET SerialPort DataReceived event not firing, I make my code like that.
namespace ConsoleApplication1
{
class Program
{
static SerialPort ComPort;
public static void OnSerialDataReceived(object sender, SerialDataReceivedEventArgs args)
{
string data = ComPort.ReadExisting();
Console.Write(data.Replace("\r", "\n"));
}
static void Main(string[] args)
{
string port = "COM4";
int baud = 9600;
if (args.Length >= 1)
{
port = args[0];
}
if (args.Length >= 2)
{
baud = int.Parse(args[1]);
}
InitializeComPort(port, baud);
string text;
do
{
String[] mystring = System.IO.Ports.SerialPort.GetPortNames();
text = Console.ReadLine();
int STX = 0x2;
int ETX = 0x3;
ComPort.Write(Char.ConvertFromUtf32(STX) + text + Char.ConvertFromUtf32(ETX));
} while (text.ToLower() != "q");
}
private static void InitializeComPort(string port, int baud)
{
ComPort = new SerialPort(port, baud);
ComPort.PortName = port;
ComPort.BaudRate = baud;
ComPort.Parity = Parity.None;
ComPort.StopBits = StopBits.One;
ComPort.DataBits = 8;
ComPort.ReceivedBytesThreshold = 9;
ComPort.RtsEnable = true;
ComPort.DtrEnable = true;
ComPort.Handshake = System.IO.Ports.Handshake.XOnXOff;
ComPort.DataReceived += OnSerialDataReceived;
OpenPort(ComPort);
}
public static void OpenPort(SerialPort ComPort)
{
try
{
if (!ComPort.IsOpen)
{
ComPort.Open();
}
}
catch (Exception e)
{
throw e;
}
}
}
}
My problem is DataReceived event never gets fired.
My program specifications are:
Just .net console programming
I use VSPE from http://www.eterlogic.com
My computer has COM1 and COM2 ports already.
I created COM2 and COM4 by using VSPE.
I get output result from mystring array (COM1, COM2, COM3, COM4)
But I still don't know why DataReceived event is not fired.
Updated
Unfortunately, I still could not make to fire DataReceived event in any way.
So, I created new project by hoping that I will face a way to solve.
At that new project [just console application], I created a class...
public class MyTest
{
public SerialPort SPCOM4;
public MyTest()
{
SPCOM4 = new SerialPort();
if(this.SerialPortOpen(SPCOM4, "4"))
{
this.SendToPort(SPCOM4, "com test...");
}
}
private bool SerialPortOpen(System.IO.Ports.SerialPort objCom, string portName)
{
bool blnOpenStatus = false;
try
{
objCom.PortName = "COM" + portName;
objCom.BaudRate = 9600;
objCom.DataBits = 8;
int SerParity = 2;
int SerStop = 0;
switch (SerParity)
{
case 0:
objCom.Parity = System.IO.Ports.Parity.Even;
break;
case 1:
objCom.Parity = System.IO.Ports.Parity.Odd;
break;
case 2:
objCom.Parity = System.IO.Ports.Parity.None;
break;
case 3:
objCom.Parity = System.IO.Ports.Parity.Mark;
break;
}
switch (SerStop)
{
case 0:
objCom.StopBits = System.IO.Ports.StopBits.One;
break;
case 1:
objCom.StopBits = System.IO.Ports.StopBits.Two;
break;
}
objCom.RtsEnable = false;
objCom.DtrEnable = false;
objCom.Handshake = System.IO.Ports.Handshake.XOnXOff;
objCom.Open();
blnOpenStatus = true;
}
catch (Exception ex)
{
throw ex;
}
return blnOpenStatus;
}
private bool SendToPort(System.IO.Ports.SerialPort objCom, string strText)
{
try
{
int STX = 0x2;
int ETX = 0x3;
if (objCom.IsOpen && strText != "")
{
objCom.Write(Char.ConvertFromUtf32(STX) + strText + Char.ConvertFromUtf32(ETX));
}
}
catch (Exception ex)
{
throw ex;
}
return true;
}
}
I am not sure that I face good luck or bad luck because this new class could make fire DataReceived event which is from older console application that is still running. It is miracle to me which I have no idea how this happen.
Let me tell you more detail so that you could give me suggestion for better way.
Finally I created 2 console projects.
First project is the class which I posted as a question yesterday.
Second project is the class called MyTest which could make fire DataReceived event from First project, at the same time when two of the project is running.
Could anyone give me suggestions on how could I combine these two projects as a single project?
ComPort.Handshake = Handshake.None;
The problem is not that the DataReceived event doesn't fire, the problem is that the serial port isn't receiving any data. There are very, very few serial devices that use no handshaking at all. If you set it to None then the driver won't turn on the DTR (Data Terminal Ready) and RTS (Request To Send) signals. Which a serial port device interprets as "the machine is turned off (DTR)" or "the machine isn't ready to receive data (RTS)". So it won't send anything and your DataReceived event won't fire.
If you really want None then set the DTREnable and RTSEnable properties to true. But it is likely you want HandShake.RequestToSend since the device appears to be paying attention to the handshake signals.
If you still have trouble then use another serial port program like Putty or HyperTerminal to ensure the connection and communication parameters are good and the device is responsive. SysInternals' PortMon utility gives a low-level view of the driver interaction so you can compare good vs bad.
I have never worked with VSPE so I'm not sure if that causes the problem. I have worked with a COM port before and I looked up my code. The only main difference is the way you declare the event. You have:
ComPort.DataReceived += OnSerialDataReceived;
I have it like this:
ComPort.DataReceived += new SerialDataReceivedEventHandler(OnSerialDataReceived);
OnSerialDataReceived is your eventhandler. I'm not sure if this will make any difference, but you can try it. I hope this helps!
I had a quite similar problem. In a graphical application (C# win form) I had a class which encapsulate a SerialPort component. The DataReceived event was firing only one time, but then any following data received didn't fire any event. I solved the problem by calling the Close method in my principal form Closed event function.
No idea of why that changes anything, but now it's working.
I am developing program which need to interact with COM ports.
By learning from this Q&A: .NET SerialPort DataReceived event not firing, I make my code like that.
namespace ConsoleApplication1
{
class Program
{
static SerialPort ComPort;
public static void OnSerialDataReceived(object sender, SerialDataReceivedEventArgs args)
{
string data = ComPort.ReadExisting();
Console.Write(data.Replace("\r", "\n"));
}
static void Main(string[] args)
{
string port = "COM4";
int baud = 9600;
if (args.Length >= 1)
{
port = args[0];
}
if (args.Length >= 2)
{
baud = int.Parse(args[1]);
}
InitializeComPort(port, baud);
string text;
do
{
String[] mystring = System.IO.Ports.SerialPort.GetPortNames();
text = Console.ReadLine();
int STX = 0x2;
int ETX = 0x3;
ComPort.Write(Char.ConvertFromUtf32(STX) + text + Char.ConvertFromUtf32(ETX));
} while (text.ToLower() != "q");
}
private static void InitializeComPort(string port, int baud)
{
ComPort = new SerialPort(port, baud);
ComPort.PortName = port;
ComPort.BaudRate = baud;
ComPort.Parity = Parity.None;
ComPort.StopBits = StopBits.One;
ComPort.DataBits = 8;
ComPort.ReceivedBytesThreshold = 9;
ComPort.RtsEnable = true;
ComPort.DtrEnable = true;
ComPort.Handshake = System.IO.Ports.Handshake.XOnXOff;
ComPort.DataReceived += OnSerialDataReceived;
OpenPort(ComPort);
}
public static void OpenPort(SerialPort ComPort)
{
try
{
if (!ComPort.IsOpen)
{
ComPort.Open();
}
}
catch (Exception e)
{
throw e;
}
}
}
}
My problem is DataReceived event never gets fired.
My program specifications are:
Just .net console programming
I use VSPE from http://www.eterlogic.com
My computer has COM1 and COM2 ports already.
I created COM2 and COM4 by using VSPE.
I get output result from mystring array (COM1, COM2, COM3, COM4)
But I still don't know why DataReceived event is not fired.
Updated
Unfortunately, I still could not make to fire DataReceived event in any way.
So, I created new project by hoping that I will face a way to solve.
At that new project [just console application], I created a class...
public class MyTest
{
public SerialPort SPCOM4;
public MyTest()
{
SPCOM4 = new SerialPort();
if(this.SerialPortOpen(SPCOM4, "4"))
{
this.SendToPort(SPCOM4, "com test...");
}
}
private bool SerialPortOpen(System.IO.Ports.SerialPort objCom, string portName)
{
bool blnOpenStatus = false;
try
{
objCom.PortName = "COM" + portName;
objCom.BaudRate = 9600;
objCom.DataBits = 8;
int SerParity = 2;
int SerStop = 0;
switch (SerParity)
{
case 0:
objCom.Parity = System.IO.Ports.Parity.Even;
break;
case 1:
objCom.Parity = System.IO.Ports.Parity.Odd;
break;
case 2:
objCom.Parity = System.IO.Ports.Parity.None;
break;
case 3:
objCom.Parity = System.IO.Ports.Parity.Mark;
break;
}
switch (SerStop)
{
case 0:
objCom.StopBits = System.IO.Ports.StopBits.One;
break;
case 1:
objCom.StopBits = System.IO.Ports.StopBits.Two;
break;
}
objCom.RtsEnable = false;
objCom.DtrEnable = false;
objCom.Handshake = System.IO.Ports.Handshake.XOnXOff;
objCom.Open();
blnOpenStatus = true;
}
catch (Exception ex)
{
throw ex;
}
return blnOpenStatus;
}
private bool SendToPort(System.IO.Ports.SerialPort objCom, string strText)
{
try
{
int STX = 0x2;
int ETX = 0x3;
if (objCom.IsOpen && strText != "")
{
objCom.Write(Char.ConvertFromUtf32(STX) + strText + Char.ConvertFromUtf32(ETX));
}
}
catch (Exception ex)
{
throw ex;
}
return true;
}
}
I am not sure that I face good luck or bad luck because this new class could make fire DataReceived event which is from older console application that is still running. It is miracle to me which I have no idea how this happen.
Let me tell you more detail so that you could give me suggestion for better way.
Finally I created 2 console projects.
First project is the class which I posted as a question yesterday.
Second project is the class called MyTest which could make fire DataReceived event from First project, at the same time when two of the project is running.
Could anyone give me suggestions on how could I combine these two projects as a single project?
ComPort.Handshake = Handshake.None;
The problem is not that the DataReceived event doesn't fire, the problem is that the serial port isn't receiving any data. There are very, very few serial devices that use no handshaking at all. If you set it to None then the driver won't turn on the DTR (Data Terminal Ready) and RTS (Request To Send) signals. Which a serial port device interprets as "the machine is turned off (DTR)" or "the machine isn't ready to receive data (RTS)". So it won't send anything and your DataReceived event won't fire.
If you really want None then set the DTREnable and RTSEnable properties to true. But it is likely you want HandShake.RequestToSend since the device appears to be paying attention to the handshake signals.
If you still have trouble then use another serial port program like Putty or HyperTerminal to ensure the connection and communication parameters are good and the device is responsive. SysInternals' PortMon utility gives a low-level view of the driver interaction so you can compare good vs bad.
I have never worked with VSPE so I'm not sure if that causes the problem. I have worked with a COM port before and I looked up my code. The only main difference is the way you declare the event. You have:
ComPort.DataReceived += OnSerialDataReceived;
I have it like this:
ComPort.DataReceived += new SerialDataReceivedEventHandler(OnSerialDataReceived);
OnSerialDataReceived is your eventhandler. I'm not sure if this will make any difference, but you can try it. I hope this helps!
I had a quite similar problem. In a graphical application (C# win form) I had a class which encapsulate a SerialPort component. The DataReceived event was firing only one time, but then any following data received didn't fire any event. I solved the problem by calling the Close method in my principal form Closed event function.
No idea of why that changes anything, but now it's working.
I'm experiencing this problem while opening a serial port in C# (which should be dirt simple; or so I thought).
When I try to open a serial port, I am getting the following exception:
The semaphore time-out period has expired.
Here is the method that is doing this.
public static void Open_TheActivePortWeWillUse(String Drone_StringNameFromUser)
{
var TempSerialPort = new SerialPort (
Drone_StringNameFromUser,
(int) SerialPortParameter.TheSerialPortSpeed);
// Now we have a name that anybody can see and use
OurSpecificPorts.TheActivePortWeAreUsing = TempSerialPort;
// We'll do 8-N-1 since almost the whole planet does that
OurSpecificPorts.TheActivePortWeAreUsing.DataBits = 8;
// We'll do 8-N-1
OurSpecificPorts.TheActivePortWeAreUsing.Parity = Parity.None;
// We'll do 8-N-1
OurSpecificPorts.TheActivePortWeAreUsing.StopBits = StopBits.One;
OurSpecificPorts.TheActivePortWeAreUsing.DataReceived +=
OurBackGroundSerialPortReceiver;
// We can now open our active port, which is what this line does
OurSpecificPorts.TheActivePortWeAreUsing.Open();
}
The strangest thing for me is that I get this error inconsistently. Half the time it works okay, and the other half, it does not.
Does anybody see anything obviously wrong with my code? Am I missing something?
Declaring your SerialPort object inside the method will not allow access to it after the method closes. Here is a method that works to open the port:
private void OpenSerialPort(String portName)
{
try
{
serialPort1.Close();
serialPort1.PortName = portName;
serialPort1.BaudRate = 115200;
serialPort1.DataBits = 8;
serialPort1.Handshake = Handshake.None;
serialPort1.Parity = Parity.None;
serialPort1.RtsEnable = false;
serialPort1.StopBits = StopBits.One;
serialPort1.Open();
}
catch (Exception ex)
{
MessageBox.Show("Could not open serial port " + portName, "Error");
}
}
The SerialPort object is declared in the class:
namespace Arcadia
{
public partial class Form1 : Form
{
private SerialPort serialPort1;
And the callback is added in the constructor:
public Form1()
{
InitializeComponent();
serialPort1.DataReceived += new SerialDataReceivedEventHandler(this.SerialPortReadCallback);
Sending data is handled in a different method:
private void SerialPortWrite(String writeString)
{
if (serialPort1.IsOpen)
{
serialPort1.WriteLine(writeString);
}
}
And here is the received data callback:
private void SerialPortReadCallback(object sender, SerialDataReceivedEventArgs args)
{
try
{
while (serialPort1.BytesToRead > 0)
{
// Do something with the data
}
}
catch (Exception ex)
{
}
}