Extracting RFID Tag's CRC Hex value using VB 6.0

[VictorTan]

Hello. I'm new to this forum. Hope that I don't make mistakes in here but if I do, please correct me if there is. Thanks.

I also wanted to ask you guys regarding about the following following source codes I'm going to post it here as I did a search here and did not find any question related to mine.

I'm doing an automatic inventory control system using RFID project and I'm instructed to extract the RFID transponder's ID and CRC and display it onto the form I've created using Visual Basic 6.0 before I touch up on the database portion which I need not need to worry much about. I managed to get the program to extract the transponder's ID and display it onto the textbox but I'm having problems extracting the CRC Hex value I'm not sure which part of the code I'm suppose to addon (See below).

Public Sub Display_Msg(sMsg As String)
 
   frmMain.txtDisplay.Text = frmMain.txtDisplay.Text + sMsg
 
End Sub
 
Public Function Hex2Str(Hex_String As String) As String
    Dim iPos As Integer
    Dim iTemp As Integer
    Dim sMsg As String
    Dim b As String
    Dim gPos As Integer
    Dim g As String
 
 
   For iPos = 8 To Len(Hex_String) - 2
        iTemp = Asc(Mid$(Hex_String, iPos, 2))
 
        If iTemp < 17 Then sMsg = sMsg + "0"
            g = iTemp
            b = b & Chr$(g)
            sMsg = sMsg + Hex(iTemp) + " "
 
   Next iPos
 
 
        frmMain.txtDisplay.Text = frmMain.txtDisplay.Text & _
            "PC -> Reader: 07 FF B0 01 00 1C 56" & vbCrLf
 
        frmMain.txtDisplay.Text = frmMain.txtDisplay.Text & _
            "PC <- Reader: " & sMsg & vbCrLf
        taginput_crc = frmMain.txtDisplay.Text
 
        frmMain.txtDisplay.Text = taginput_crc & _
            "PC <- Reader: 11 FF B0 23 01 " & sMsg & "00 01 " & vbCrLf & vbCrLf
 
        frmMain.MSComm1.Output = Chr$(&H11) + Chr$(&HFF) + Chr$(&HB0) & _
            Chr$(&H23) + Chr$(&H1) + sMsg + Chr$(&H0) + Chr$(&H1) & _
            frmMain.Text2.Text
 
        frmMain.txtDisplay.Text = taginput_crc & _
            "PC -> Reader: 11 FF B0 23 01 " & sMsg & "00 01 " & frmMain.Text2.Text & vbCrLf & vbCrLf
 
 
        frmShoes.txtShoeTag.Text = "11 FF B0 23 01" & sMsg + "00 01"
        frmShirt.txtShirtTag.Text = "11 FF B0 23 01" & sMsg + "00 01"
 
 
        sbuffer = Chr$(&H11) + Chr$(&HFF) + Chr$(&HB0) + Chr$(&H23) + Chr$(&H1) + b + Chr$(&H0) + Chr$(&H1)
 
        crc_output = CalcCRC16CheckSum(sbuffer, Len(sbuffer))
 
        buflen = Len(sbuffer)
        frmMain.Text1.Text = Len(sbuffer)
 
End Function

And also for example, if my CRC value is "D1B8" which isn't correct as the program calculates D1 as MSB and B8 as LSB, what must be edited to obtain the CRC value "B8D1" as this is actually the correct value (see below)?

Public Function CalcCRC16CheckSum(sbuffer As String, buflen As Byte) As Integer
 
    Dim i, j As Byte
    Dim wCrc As Integer
    Initialise_mPower
    wCrc = CRC16_PRESET
 
    For i = 1 To buflen
 
        wCrc = wCrc Xor Asc(Mid$(sbuffer, i, 1))
        For j = 1 To 8
            If (wCrc And &H1) Then
                wCrc = LShift(wCrc, 1) Xor POLYNOM
            Else
                wCrc = LShift(wCrc, 1)
            End If
        Next j
    Next i
 
    crc_output = wCrc
 
    frmMain.crcdisplay.Text = crc_output
    a = Hex(crc_output)
    frmMain.Text2.Text = a
 
End Function
 
Public Function LShift(ivalue As Integer, iBits As Integer) As Integer
 
    If (ivalue And mPower2(15)) = mPower2(15) Then
        LShift = (ivalue And &H7FFF) \ mPower2(iBits) Or mPower2(15 - iBits)
    Else
        LShift = ivalue \ mPower2(iBits)
    End If
 
End Function
 
Public Function RShift(ivalue As Integer, iBits As Integer) As Integer
 
    If (ivalue And mPower2(15 - iBits)) = mPower2(15 - iBits) Then
        RShift = (ivalue And (mPower2(15 - iBits) - 1)) * mPower2(iBits) Or mPower2(15)
    Else
        RShift = (ivalue And (mPower2(15 - iBits) - 1)) * mPower2(iBits)
    End If
 
End Function

Sorry if I posted a big chunk of code in here as I'm unsure of which portion of the code I'm suppose to look into.

Thanks for the help.

[VictorTan]

I assuming that nobody could answer this? I have been waiting for a reply on this since last week. Thanks again.

[VictorTan]

Can't anyone help? If can't please let me know. Thank you.