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I checked and serial port in enabled in BIOS. The driver is the Microsoft driver serial.sys and claims it is working. I believe the. Drivers: BSOD using USB serial port Sometimes during the debugging of a blackbox via RS-232, my PC crashes with a BSOD. The serial port is working at 9600bps 8N1.
This topic describes how to use
My.Computer.Ports
to receive strings from the computer's serial ports in Visual Basic.To receive strings from the serial port
- Initialize the return string.
- Determine which serial port should provide the strings. This example assumes it is
COM1
. - Use the
My.Computer.Ports.OpenSerialPort
method to obtain a reference to the port. For more information, see OpenSerialPort.TheTry...Catch...Finally
block allows the application to close the serial port even if it generates an exception. All code that manipulates the serial port should appear within this block. - Create a
Do
loop for reading lines of text until no more lines are available. - Use the ReadLine() method to read the next available line of text from the serial port.
- Use an
If
statement to determine if the ReadLine() method returnsNothing
(which means no more text is available). If it does returnNothing
, exit theDo
loop. - Add an
Else
block to theIf
statement to handle the case if the string is actually read. The block appends the string from the serial port to the return string. - Return the string.
Example
This code example is also available as an IntelliSense code snippet. In the code snippet picker, it is located in Connectivity and Networking. For more information, see Code Snippets.
Compiling the Code
This example assumes the computer is using
COM1
.Robust Programming
This example assumes the computer is using
COM1
. For more flexibility, the code should allow the user to select the desired serial port from a list of available ports. For more information, see How to: Show Available Serial Ports.This example uses a
Try...Catch...Finally
block to make sure that the application closes the port and to catch any timeout exceptions. For more information, see Try...Catch...Finally Statement.