CRC calculation

**tom_rosenback** · 11-17-2008, 02:50 AM

Hi, does anybody know how to figure out the CRC algorithm if a given code + CRC string is given? I have got several strings consisting of code + matching CRCs but don´t know how to calculate the CRC in question so that I could produce more code strings. Here are some samples (16bit code + 4bt CRC):

0010101000011101 + 0000
0010101000011111 + 0001
1000110011101101 + 0001
0000000000000100 + 0010
0011100011001110 + 0011
1000110011101110 + 0100
0001011110101100 + 0100
0010101000011110 + 0101
0011100011001101 + 0110
0001011110101111 + 0111
0011100011001100 + 1001
0011100011001111 + 1010
0001011110101101 + 1011
0000000000001000 + 1011
0000111100001101 + 1100
0000000000001100 + 1100
1111111111111111 + 1101
1000110011101111 + 1101
1000110011101100 + 1110
0001011110101110 + 1110
1111111100001101 + 1110
0010101000011100 + 1111

These codes come from a RF (433MHz) sender like the X10 products.

Hopefully there is someone out there that can help me!!

**ClockWorK** · 11-17-2008, 02:24 PM

http://en.wikipedia.org/wiki/Cyclic_redundancy_check
The Computation section is particularly good.

**tom_rosenback** · 11-17-2008, 04:18 PM

Thx for your link. I have had a look at the wiki page, without results. I have tried to do the calculations as mentioned in the wiki but can´t manage to get the correct CRC calculated... Is there anyone who can help me with this?

Any help in any way is appreciated!