'Data为字符型数组 start为开始点 size 为几个,返回的即为 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 '多项式码&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) '每一个数据与CRC寄存器进行异或
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 '如果高位字节最后一位为1
CRC16Lo = CRC16Lo Or &H80 '则低位字节右移后前面补1
End If '否则自动补0
If ((SaveLo And &H1) = &H1) Then '如果LSB为1，则与多项式码进行异或
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) '低位处理
CRC16Hi = GetCRCLo(iIndex) '高位处理
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低位字节值表
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高位字节值表
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