Visual Basic CI-V Example

I have received a few requests for an example of CI-V programming using Visual Basic .Net. While my VB is pretty rusty, I decided to try and convert one of my examples from C# to VB.Net. The conversion was very straightforward. As with the C# example this has minimal error checking and would need better error checking, collision detection, and retries for failed commands in a true production quality implementation

Here is what I ended up with.

Imports System.IO.Ports
Imports System.Text.RegularExpressions

Module Module1

    Public Class ICOM7300
        Private ReadOnly port As String
        Private ReadOnly baudRate As Long
        Private serialPort As SerialPort

        Public Sub New(portValue As String, baudRateValue As Long)
            port = portValue
            baudRate = baudRateValue
            serialPort = Nothing
        End Sub

        Public Sub Open()
            serialPort = New SerialPort(port, baudRate, Parity.None, 8, StopBits.One)
            ' Throws an exception if the serial port fails to open
            serialPort.Open()
            serialPort.ReadTimeout = 500
            serialPort.WriteTimeout = 500
        End Sub

        Public Sub Close()
            If serialPort IsNot Nothing Then
                If (serialPort.IsOpen) Then
                    serialPort.Close()
                End If
                serialPort.Dispose()
            End If
            serialPort = Nothing
        End Sub

        Public Function OperatingFrequency() As Integer
            If serialPort Is Nothing Or serialPort.IsOpen = False Then
                Throw New Exception("Serial port is not open to get OperatingFrequency")
            End If

            Dim request() As Byte = New Byte() {&HFE, &HFE, &H94, &HE0, &H3, &HFD}
            serialPort.Write(request, 0, request.Length)

            Dim response As List(Of Byte)
            response = GetResponse()

            Dim frequency As Long
            frequency = (response(5) And &HF) + (((response(5) >> 4) And &HF) * 10) +
                ((response(6) And &HF) * 100) + (((response(6) >> 4) And &HF) * 1000) +
                ((response(7) And &HF) * 10000) + (((response(7) >> 4) And &HF) * 100000) +
                ((response(8) And &HF) * 1000000) + (((response(8) >> 4) And &HF) * 10000000) +
                ((response(9) And &HF) * 100000000) + (((response(9) >> 4) And &HF) * 1000000000)

            Return frequency
        End Function

        Private Function GetResponse() As List(Of Byte)
            If serialPort Is Nothing Then Return Nothing

            Dim response As List(Of Byte)
            response = FillBuffer()
            While response(2) <> &HE0 Or response(3) <> &H94 or response(4) <> &H3
                response = FillBuffer()
            End While
            Return response
        End Function

        Private Function FillBuffer() As List(Of Byte)
            Dim response As List(Of Byte) = New List(Of Byte)()
            Dim inByte As Byte

            inByte = serialPort.ReadByte() And &HFF
            While (inByte <> &HFD)
                response.Add(inByte)
                inByte = serialPort.ReadByte() And &HFF
            End While

            response.Add(inByte)
            Return response
        End Function

    End Class

    Function ValidateComPort(port As String) As Boolean
        Dim ports As String()
        ports = SerialPort.GetPortNames()

        For Each comPort As String In ports
            If (comPort.Equals(port, StringComparison.OrdinalIgnoreCase)) Then
                Return True
            End If
        Next

        Return False
    End Function

    Sub Main(args As String())
        Dim port As String = ""
        Dim baudRate As String = "115200"
        Dim ic7300 As ICOM7300

        For Each arg As String In args
            If ValidateComPort(arg) Then
                port = arg
            ElseIf Regex.IsMatch(arg, "^\d+$") Then
                baudRate = arg
            Else
                ' show usage And return
                Console.WriteLine("usage: Set-7300Clock comport <baudrate>")
                Return
            End If
        Next

        ' We must have a port.  Everything else can be default
        If port.Equals("") Then
            ' show usage And return
            Console.WriteLine("usage: Set-7300Clock comport <baudrate>")
            Return
        End If

        ic7300 = New ICOM7300(port, Long.Parse(baudRate))

        Try
            ic7300.Open()
            Dim frequency As Long = ic7300.OperatingFrequency
            Console.WriteLine("Operating frequency is {0}", frequency)
        Catch ex As Exception
            Console.WriteLine("Error getting operating frequency")
            Console.WriteLine(ex.Message)
            Console.WriteLine("Make sure that {0} is the port the IC-7300 is connected to and not in use by any other software.", port)
        Finally
            ic7300.Close()
        End Try
    End Sub

End Module