vb.net serial Communication (SerialPort control) __.net

' Load native all COM

Sub Getserialportnames ()
For the SP as String in My.Computer.Ports.SerialPortNames
COMBOBOX1.ITEMS.ADD (SP)
Next
If ComboBox1.Items.Count > 0 Then
Combobox1.selectedindex = 0
End If
End Sub

' Open the serial port

If Serialport1.isopen Then
Serialport1.close ()
End If

        Try
             with SerialPort1
                . PortName = Combobox1.text
                . BaudRate = 9600

               . Parity = IO. Ports.Parity.None ' Parity
                . DataBits = 8 ' data bit
               . StopBits = IO. Ports.StopBits.One ' Stop bit
            end with
             ' Open
             Serialport1.open ()

Label1.Text = "Connected"
button1.enabled = False
button2.enabled = True
Catch ex as Exception
MsgBox (ex. ToString)
End Try

' Close the serial port

Serialport1.close ()

' Send data

General data

Dim data As String=textbox1.text

Serialport1.write (data)

hexadecimal string

When sending a hexadecimal string, we use an array to save the information to be sent

For example, send data: FF-FE

Try
Dim data (8) as Byte
Data (0) = &hff
Data (1) = &h1
Data (2) = &h0
Data (3) = &h0
Data (4) = &h1
Data (5) = &h0
Data (6) = &h0
Data (7) = &hfe
Serialport1.discardoutbuffer ()
Serialport1.write (data, 0, 8)
Catch ex as Exception
MsgBox (ex. ToString)
End Try

Receive data

SerialPort has a datareceived event where we can write the accepted data code.

Accept string: serialport.readexisting

Accept Stream Data:

Dim bytetoread As Int16=serialport.bytestoread (byte length of read buffer)

Dim ch (bytetoread) as Byte

Dim bytesread As Int16=0

Bytesread=serialport.read (Ch,0,bytetoread)

For I as int16=0 to BytesRead-1

Indata=indata & Dectohex (CH (i))

Next

Indata is the data that is read

Custom Function: Dectohex (return hexadecimal character)

Public Function Dectohex (ByVal decnumber as Byte) As String ' converts to a hexadecimal string
If Decnumber <= Then
Dectohex = "0" & Hex (Decnumber)
Else:dectohex = "" & Hex (Decnumber)
End If
End Function