32 Bit CRC - Githubissues

OK-DMR / ok-dmrlib

DMR PDUs, elements, FEC and CRC library, including proprietary DMR protocols of Hytera and Motorola

GNU Affero General Public License v3.0

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32 Bit CRC #11

Closed alwinhb closed 4 months ago

alwinhb commented 5 months ago

Hi @smarek

Can you help me understand the CRC 32 Bit used in this code,

For data sample "d6790062620003bf000700000000000000000000" your CRC32 is "210b9a3d"
```
As per my understanding of your code, we are doing the following steps -
1. First is byte swap
o/p: 79d662000062bf03070000000000000000000000
2. Then for each byte, we are doing bit reverse
o/p: 9E6B46000046FDC0E00000000000000000000000
3. And applying crc32 with polynomial: 0X04C11DB7
```
But as I follow the above steps on my code using the same data sample my CRC32 bits come to be different. The other things like CC, and Data/Payload look good while decoding but my CRC Comes out to be different.

smarek commented 4 months ago

Well I hope you figured it out, without your code I cannot help, and honestly, you're just re-implementing ok-dmrlib in C/C++ and closed-source, so I'll not support you, unless it's a paid work. Good luck with your project