VB 的CRC16校正演算法 )

'Data為字元型數組 start為開始點 size 為幾個,返回的即為 CRC
Public Function CRC16(Data() As Byte, start As Integer, size As Integer) As Long
    Dim CRC16Lo     As Byte, CRC16Hi       As Byte        'CRC寄存器
    Dim CL     As Byte, CH       As Byte                  '多項式碼&HA001
    Dim SaveHi     As Byte, SaveLo       As Byte
    Dim i     As Integer
    Dim Flag     As Integer
    CRC16Lo = &HFF
    CRC16Hi = &HFF
    CL = &H1
    CH = &HA0
    For i = 0 To size - 1
        CRC16Lo = CRC16Lo Xor Data(start + i)         '每一個資料與CRC寄存器進行異或
        For Flag = 0 To 7
            SaveHi = CRC16Hi
            SaveLo = CRC16Lo
            CRC16Hi = CRC16Hi \ 2                    '高位右移一位
            CRC16Lo = CRC16Lo \ 2                    '低位右移一位
            If ((SaveHi And &H1) = &H1) Then               '如果高位位元組最後一位為1
                CRC16Lo = CRC16Lo Or &H80              '則低位位元組右移後前面補1
            End If                               '否則自動補0
            If ((SaveLo And &H1) = &H1) Then               '如果LSB為1，則與多項式碼進行異或
                CRC16Hi = CRC16Hi Xor CH
                CRC16Lo = CRC16Lo Xor CL
            End If
        Next Flag
    Next i
    CRC16 = CRC16Hi               'CRC高位
    CRC16 = CRC16 * 256
    CRC16 = CRC16 + CRC16Lo            'CRC低位
End Function

 

查表法：

Private Sub CRC16(data() As Byte)
    Dim CRC16Hi As Byte
    Dim CRC16Lo As Byte
    ReDim ReturnData(2) As Byte
    CRC16Hi = &HFF
    CRC16Lo = &HFF
    Dim i As Integer
    Dim iIndex As Long
    For i = 0 To UBound(data)
        iIndex = CRC16Lo Xor data(i)
        CRC16Lo = CRC16Hi Xor GetCRCHi(iIndex)             '低位處理
        CRC16Hi = GetCRCLo(iIndex)                         '高位處理
    Next i

    ReturnData(0) = CRC16Hi                                'CRC高位
    ReturnData(1) = CRC16Lo                                'CRC低位

    '    For i = 0 To UBound(ReturnData)
    '        Text9.Text = Text9.Text & Hex(ReturnData(i))
    '    Next i
    Text7.Text = Hex(ReturnData(1))
    Text8.Text = Hex(ReturnData(0))
    Text9.Text = Hex(ReturnData(1)) & Hex(ReturnData(0))
End Sub

'CRC低位位元組值表
    Function GetCRCLo(Ind As Long) As Byte
    GetCRCLo = Choose(Ind + 1, &H0, &HC0, &HC1, &H1, &HC3, &H3, &H2, &HC2, &HC6, &H6, _
            &H7, &HC7, &H5, &HC5, &HC4, &H4, &HCC, &HC, &HD, &HCD, _
            &HF, &HCF, &HCE, &HE, &HA, &HCA, &HCB, &HB, &HC9, &H9, _
            &H8, &HC8, &HD8, &H18, &H19, &HD9, &H1B, &HDB, &HDA, &H1A, _
            &H1E, &HDE, &HDF, &H1F, &HDD, &H1D, &H1C, &HDC, &H14, &HD4, _
            &HD5, &H15, &HD7, &H17, &H16, &HD6, &HD2, &H12, &H13, &HD3, _
            &H11, &HD1, &HD0, &H10, &HF0, &H30, &H31, &HF1, &H33, &HF3, _
            &HF2, &H32, &H36, &HF6, &HF7, &H37, &HF5, &H35, &H34, &HF4, _
            &H3C, &HFC, &HFD, &H3D, &HFF, &H3F, &H3E, &HFE, &HFA, &H3A, _
            &H3B, &HFB, &H39, &HF9, &HF8, &H38, &H28, &HE8, &HE9, &H29, _
            &HEB, &H2B, &H2A, &HEA, &HEE, &H2E, &H2F, &HEF, &H2D, &HED, _
            &HEC, &H2C, &HE4, &H24, &H25, &HE5, &H27, &HE7, &HE6, &H26, _
            &H22, &HE2, &HE3, &H23, &HE1, &H21, &H20, &HE0, &HA0, &H60, _
            &H61, &HA1, &H63, &HA3, &HA2, &H62, &H66, &HA6, &HA7, &H67, _
            &HA5, &H65, &H64, &HA4, &H6C, &HAC, &HAD, &H6D, &HAF, &H6F, _
            &H6E, &HAE, &HAA, &H6A, &H6B, &HAB, &H69, &HA9, &HA8, &H68, _
            &H78, &HB8, &HB9, &H79, &HBB, &H7B, &H7A, &HBA, &HBE, &H7E, _
            &H7F, &HBF, &H7D, &HBD, &HBC, &H7C, &HB4, &H74, &H75, &HB5, _
            &H77, &HB7, &HB6, &H76, &H72, &HB2, &HB3, &H73, &HB1, &H71, _
            &H70, &HB0, &H50, &H90, &H91, &H51, &H93, &H53, &H52, &H92, _
            &H96, &H56, &H57, &H97, &H55, &H95, &H94, &H54, &H9C, &H5C, _
            &H5D, &H9D, &H5F, &H9F, &H9E, &H5E, &H5A, &H9A, &H9B, &H5B, _
            &H99, &H59, &H58, &H98, &H88, &H48, &H49, &H89, &H4B, &H8B, _
            &H8A, &H4A, &H4E, &H8E, &H8F, &H4F, &H8D, &H4D, &H4C, &H8C, _
            &H44, &H84, &H85, &H45, &H87, &H47, &H46, &H86, &H82, &H42, &H43, &H83, &H41, &H81, &H80, &H40)
End Function

'CRC高位位元組值表
    Function GetCRCHi(Ind As Long) As Byte
    GetCRCHi = Choose(Ind + 1, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _
            &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _
            &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, _
            &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, _
            &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H0, &HC1, _
            &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, &H80, &H41, _
            &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H0, &HC1, _
            &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _
            &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _
            &H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, _
            &H1, &HC0, &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, _
            &H81, &H40, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, _
            &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _
            &H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, _
            &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, _
            &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, _
            &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _
            &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _
            &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, _
            &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _
            &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, _
            &H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, _
            &H1, &HC0, &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, _
            &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _
            &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40)
End Function