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Serial Frame Error with No Connection


#1

I never noticed this before on my Cobra board , but it may be normal…

If I send data out a UART when the connections of the port are left disconnected I get frame errors on the SerialPort error event. Is this normal? My Domino does not exhibit this behavior.



static SerialPort UART = new SerialPort("COM1", 115200);
UART.Open();
byte[] buffer = Encoding.UTF8.GetBytes("String");
// send the bytes on the serial port
UART.Write(buffer, 0, buffer.Length);


-AP


#2

You should never leave input pins unconnected.


#3

I appreciate that, but I allow the user to plug a into the Cobra so it is possible for the connection to be left unconnected and data be transmitted. I just thought it strange that I got frame errors in that case. Do you or anyone else see the same behavior with your EMX/Cobra?

-AP


#4

What you see is expected and is normal. You can add a pull up resistor to the pin if you do not need it.