CRC12

[Tonyparker]

Hi all, I was not so far from a solution but if I can get some help please to calculate a CRC12 on 12bit of 39 words of 16bits...

The polynomial is x^12+ x^11 + x^3 + x^2 +x +1 and the recprocal notation is 0cC07.

Thanks a a lot in advance

Jérémie

[ogk.nz]

Do you have any attempts made at trying to solve this yourself?

Also do you have some correct CRC conversion data so that even if we wanted to solve your problem for you we could test that our solutions actually worked.

[Tonyparker]

Hello 

Thanks for first answer. Of course I will try myself but some parts are not fully clear.

Here the data for a CRC code = 0x499

Hexa
8000
0019
4400
0004
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
BAE0
0004
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
70C3
0004
0054
0001
0000
0000
003C
0000

I have an excel macro code:

#########################################
' bit-serial calculation (more straightforward)
' #########################################
For j = 0 To 15
' get LSB of the word
Bit = d(15 - j)
' create the lfsr
NewCrc(11) = Crc(10) Xor Bit Xor Crc(11)
NewCrc(10) = Crc(9)
NewCrc(9) = Crc(8)
NewCrc(8) = Crc(7)
NewCrc(7) = Crc(6)
NewCrc(6) = Crc(5)
NewCrc(5) = Crc(4)
NewCrc(4) = Crc(3)
NewCrc(3) = Crc(2) Xor Bit Xor Crc(11)
NewCrc(2) = Crc(1) Xor Bit Xor Crc(11)
NewCrc(1) = Crc(0) Xor Bit Xor Crc(11)
NewCrc(0) = Bit Xor Crc(11)
'Crc(0) = Bit Xor DoInvert
'Debug.Print "0x" & Hex(convert_to_long(Crc))
For k = 0 To 11
Crc(k) = NewCrc(k)
Next k
Next j
' create normal view of Crc
CrcLong = convert_to_long(Crc)
Debug.Print i & " " & ActiveSheet.Cells(StartRow + i, StartColumn).Value & " 0x" & Hex(CrcLong)
CrcString = Hex(CrcLong)
ActiveSheet.Cells(StartRow + i, StartColumn + 1).Value = "0x" & Replace(Space(3 - Len(CrcString)), " ", "0") & CrcString
Next i