UWP C# UART RS485 Polling Issue

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Hi, I have my UART for RS485 using a FTDI USB to 485 cable connected to Raspberry Pi on Windows IoT Core. I set a dispatchertimer at every 1second to transmit polling to respective field devices. I am able to tx and rx the 485 data with no problem. However, after the polling loop to about 20 times it just crash and exited the debug mode. I used try & catch to trap the exception but could not get it. However, i manage to read the error message at the debug output pane - The program [0xBB0] PwD.exe' has exited with code -1073741811 (0xc000000d).


I am not sure what caused the problem and where did I do wrong?

Please help. Thanks.



private void PollTimer_Tick(object sender, object e)
{
if (pollCounter <= maxDevice)
{
var a = pollCounter | 0x80;
pollCounter++;

TxAdr = Convert.ToByte(a);
TxCmd = TxPoll;

TxPollCard();

}
else pollCounter = 0;
}

private async void TxPollCard()
{
if (serialPort != null)
{
List<byte> data = new List<byte>();

data.Add(TxHeader);
data.Add(TxAdr);
data.Add(TxCmd);

TxChkSum = 0;
foreach (byte a in data)
{
TxChkSum += a;
}

TxChkSum = (byte)(TxChkSum - 0x80);
data.Add(TxChkSum);

try
{
// Create the DataWriter object and attach to OutputStream
dataWriteObject = new DataWriter(serialPort.OutputStream);

dataWriteObject.WriteBytes(data.ToArray());

Task<UInt32> storeAsyncTask;
// Launch an async task to complete the write operation
storeAsyncTask = dataWriteObject.StoreAsync().AsTask();

UInt32 bytesWritten = await storeAsyncTask;

dataWriteObject.DetachBuffer();
}
catch (Exception ex)
{
await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
{
MainStatusDisplay.Text = ex.Message;
});
}

}
else
{
await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
{
MainStatusDisplay.Text = "No UART port found";
});
}
}






I have previously posted regarding the issue but haven't really found the problem. Recently, I found this post regarding detachbuffer and wonder if this could be the reason i encounter the problem.

I have my UART for RS485 using a FTDI USB to 485 cable connected to Raspberry Pi on Windows IoT Core. I set a dispatchertimer at every 1second to transmit polling to respective field devices. I am able to tx and rx the 485 data with no problem. However, after the polling loop to about 20 times it just crash and exited the debug mode. I used try & catch to trap the exception but could not get it. However, i manage to read the error message at the debug output pane - The program [0xBB0] PwD.exe' has exited with code -1073741811 (0xc000000d).


I have previously posted regarding the issue but haven't really found the problem. Recently, I found this post regarding detachbuffer and wonder if this could be the reason i encounter the problem.

I have my UART for RS485 using a FTDI USB to 485 cable connected to Raspberry Pi on Windows IoT Core. I set a dispatchertimer at every 1second to transmit polling to respective field devices. I am able to tx and rx the 485 data with no problem. However, after the polling loop to about 20 times it just crash and exited the debug mode. I used try & catch to trap the exception but could not get it. However, i manage to read the error message at the debug output pane - The program [0xBB0] PwD.exe' has exited with code -1073741811 (0xc000000d).

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