serialport DataReceived event very slow -> fires after about 8sec

[jwei]

i am using an AT91RM9200 with win ce 5.0 and .net cf 2.0

using the following sample programm i try to send some chars over a serial
connection to the board with hyperterminal, but the key entered in
hyperterminal gets displayed (= DataReceived event fired) not until about
8sec ?!?

i debugged the serial driver also, and the AT91SERIAL_RxIntr gets called not
until 8sec too ... ?

any ideas ?
class Program {

static void Main(string[] args) {
SerialPort sp = new SerialPort("COM1", 9600, Parity.None, 8,
StopBits.One);
sp.Handshake = Handshake.None;

try {
sp.Open();
sp.DataReceived += new
SerialDataReceivedEventHandler(sp_DataReceived);
Thread.Sleep(Timeout.Infinite);
} catch (Exception ex) {
Console.WriteLine(ex.Message);
}
}

static void sp_DataReceived(object sender,
SerialDataReceivedEventArgs e) {
SerialPort sp = (SerialPort)sender;
try {
string s = sp.ReadExisting();
Console.WriteLine(s);
} catch (Exception ex) {
Console.WriteLine(ex.Message);
}
}
}

 

[DickGrier]

I have not seen such a delay. Are you using a device, or the emulator?

BTW, I'd remove the Try/Catch block which does slow things down (though not
to this extent). There should never be an error here, at least AFAIK.

Dick

--
Richard Grier, Consultant, Hard & Software 12962 West Louisiana Avenue
Lakewood, CO 80228 303-986-2179 (voice) Homepage: www.hardandsoftware.net
Author of Visual Basic Programmer's Guide to Serial Communications, 4th
Edition ISBN 1-890422-28-2 (391 pages) published July 2004, Revised July
2006.

 

[Markus Humm]

Hello,

I also never saw such a thing. RS232 is instant receiving of data. Seems
your RS232 driver has some problem or your hardware. Maybe it uses a
fifo which doesn't correctly report when it received some bytes or so?

Greetings

Markus

 

[B-Dawg]

I've seen this kind of delay several times and once had to spend quite a
while getting to the bottom of it .

Not sure if it is related but in my case it was because I was loading the
processor too much (but not enough that the application ground to a halt).
After I re-coded my application to be more efficient it was fine. The same
sluggish behaviour was seen with both USB to RS232 serial dongles and the
harware serial ports.

Regards,

Bevan

 

[Markus Humm]

Hello,

this could also be a case. So it the events don't come through anymore
because whtever the CPU hogs has higher pripority then thins will be
delayed until the events get a bit CPU time as well.

Greetings

Markus

 

[jwei]

i use a real hardware : AT91RM9200-DK
i will try a simple program - thanks

 

[jwei]

no success

there is no heavy load ...

maybe i should use createfile instead of serialport class (regarding
underlaying stream buffer) ?

 

[Broeden]

Hi

I had the same problem... but I gave up and are now using the GPS
Intermediete driver directly. It work very well. See SDK WM6 GPS sample

/Brofalad

 

[jwei]

did you also used at91rm9200-dk/ek ?
maybe this is an adeneo bsp driver issue (windows ce 5) ?