发布时间 : 星期一 文章CRC校验原理及其C语言实现-机电之家网PLC技术网更新完毕开始阅读
crcdata>>=1; if(crcdata&0x01) crcdata^=0xa001; } return crcdata; }
VBvbvbvbvbvbvbvvvvvvvvvvvvvvvvvvbbbbbbbbbbbbbbbbbb Private Sub Command1_Click() Dim CRC() As Byte
Dim d() As Byte '待传输数据 ReDim d(5) As Byte
d(0) = 2 '02 03 00 00 00 04 lo44 hi3A d(1) = 3 d(2) = 0 PLC
d(3) = 0 d(4) = 0
d(5) = 4 '02 03 20 40 00 04 hi2E Lo4E
CRC = CRC16(d) '调用CRC16计算函数
'CRC(0)为高位 'CRC(1)为低位 End Sub
'注意：在数据传输时CRC的低位可能在前，而高位在后。
Function CRC16(data() As Byte) As String
Dim CRC16Lo As Byte, CRC16Hi As Byte 'CRC寄存器 PLC
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 UBound(data) PLC
CRC16Lo = CRC16Lo Xor data(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 PLC资料网
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 PLC资料网
End If Next Flag Next i
Dim ReturnData(1) As Byte
ReturnData(0) = CRC16Hi 'CRC高位
ReturnData(1) = CRC16Lo 'CRC低位
CRC16 = ReturnData End Function