prolific usb to serial comm port com4 does not working

Note: Your code will also work as is sometimes, depending on these race conditions. The problem can be an error in WriteLine('Test'), you should handle errors, or it can be that your in are blocking your code ReadLine() before the WriteLine('Test') manage to come through, you could insert a Thread.Sleep(100) between, but this is not really improving the code. You block your code to wait for a line, if the line never arrives it will remain here forever or the value set to ReadTimeout The problem with your code is in this line var message = ReceiveSerialPort.ReadLine() private const Handshake defaultHandshake = Handshake.None For example, the DataBits property defaults to 8, the Parity property defaults to the None enumeration value, the StopBits property defaults to 1, and a default port name of COM1.Įven the handshake has a default value. This constructor uses default property values when none are specified. _serialPort.Handshake = SetPortHandshake(_serialPort.Handshake) Īll the constructors will give these values: _serialPort.StopBits = SetPortStopBits(_serialPort.StopBits) _serialPort.DataBits = SetPortDataBits(_serialPort.DataBits) _serialPort.Parity = SetPortParity(_serialPort.Parity) I prefer to use the default constructor (preference only) SerialPort Constructor ()Īnd then set any values like so: _serialPort.BaudRate = SetPortBaudRate(_serialPort.BaudRate)

(out of scope for this question).Īlso lacking and important is the intialisation of your ports. Usually there will be a beginning and end value within the written data to tell the other port that the message is finished and also for the ports to validate that they are reading data they should be, usually with commands of what to do with that data.

String message = ReceiveSerialPort.ReadLine() SendSerialPort.WriteLine(String.Format(': ', name, message)) If (stringComparer.Equals('quit', message)) StringComparer stringComparer = StringComparer.OrdinalIgnoreCase SerialPort ReceiveSerialPort = new SerialPort('Com4', 9600) SerialPort SendSerialPort = new SerialPort('Com3', 9600) To actually have both ports running to read and write back and forth you will actually need to implement threading for reading and writing for both. I've altered from the example you linked:

Prolific usb to serial comm port com4 does not working