Computer Interfacing
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CRC-DNP and 13757

Does not find the same result in CRC-DNP calculation ...


 

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Author Message
MarcPo
Guest







Sep 30, 2008 9:28 am

Hi
I have to use calculation of CRC in Afnor normalization 13757. In an example they give :
78 0B 13 43 65 87 and the CRC is 1E 6D
The CRC given by Lammert Bies software is 3F 98
I did several manip like complement, bit inversion, lsb to msb but nothing new ...
Can somebody help me ?
Guest








Sep 30, 2008 9:36 pm

Compared to the standard CRC-16/DNP the refin/refout are set to false and the byte of the CRC are swapped, ie with
Code:
Poly=3D65 
init=0000 
xorout=ffff 
refin=false 
refout=false

you get CRC(780B13436587) = 1E6D. But this has to be verified with other input data.

Hope that helps
GT
regregex
Preferred Member



Joined: 30 Oct 2007
Posts: 184
Location: London, UK

Sep 30, 2008 10:40 pm

Hello MarcPo, welcome to the forum!

Further to GammaTester's answer, as an example, Lammert's calculator produces 0x78B6 (=0x1E6D with the bits in each byte reflected) when given the sequence 1E D0 C8 C2 A6 E1 (the reflected message.)

For reference the Check value of this algorithm would be 0xC2B7, but again other message-CRC pairs are needed to confirm this is the algorithm being used.

--Greg
MarcPo
Guest







Oct 01, 2008 8:39 am

It seems correct in all my examples
Thanks for your help Smile

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