SerialPort ReadLine() after Thread.Sleep() goes crazy
- by Mat
Hi everybody,
I've been fighting with this issue for a day and I can't find answer for it.
I am trying to read data from GPS device trough COM port in Compact Framework C#. I am using SerialPort class (actually my own ComPort class boxing SerialPort, but it adds only two fields I need, nothing special).
Anyway.. I am running while loop in a separate thread which reads line from the port, analyze NMEA data, print them, catch all exceptions and then I Sleep(200) the thread, cause I need CPU for other threads... Without Sleep it works fine, but uses 100% CPU.. When I dont use Sleep after few minutes the output from COM port looks like this:
GPGSA,A,3,09,12,22,17,15,27,,,,,,,2.6,1.6,2.1*3F
GSA,A,3,09,12,22,17,15,27,,,,,,,2.6,1.6,2.1*3F
A,A,3,09,12,22,17,15,27,,,,,,,2.6,1.6,2.1*3F
,18,12,271,24,24,05,020,24,14,04,326,25,11,03,023,*76
A,3,09,12,22,17,15,27,,,,,,,2.6,1.6,2.1*3F
3,09,12,22,17,15,27,,,,,,,2.6,1.6,2.1*3F
09,12,22,17,15,27,,,,,,,2.6,1.6,2.1*3F
,12,22,17,15,27,,,,,,,2.6,1.6,2.1*3F
as you can see the same message is read few times but cut.
I wonder what I'm doing wrong...
My port configuration:
port.ReadBufferSize = 4096;
port.BaudRate = 4800;
port.DataBits = 8;
port.Parity = Parity.None;
port.StopBits = StopBits.One;
port.NewLine = "\r\n";
port.ReadTimeout = 1000;
port.ReceivedBytesThreshold = 100000;
And my reading function:
private void processGps(){
while (!closing)
{
//reconnect if needed
try
{
string sentence = port.ReadLine();
//here print the sentence
//analyze the sentence (this takes some time 50-100ms)
}
catch (TimeoutException)
{
Thread.Sleep(0);
}
catch (IOException ioex)
{
//handling IO exception (some info on the screen)
}
Thread.Sleep(200);
}
}
There is some more stuff in this function like reconnection if the device is lost etc.. but it is not called when the GPS is connected properly.. I was trying
port.DiscardInBuffer();
after some blocks of code (in TimeoutException, after read..)
Did anyone had similar problem? I really dont know what I'm doing wrong.. The only way to get rig of it is removing the last Sleep...
Thanks in advance!
Best Regards,
Mat
