Computer Interfacing

# Unable to detect CRC8

Author Message
Shenawy
Guest

Dec 20, 2014 1:35 pm

Hello, I need some help in identifying the algorithm of CRC

I have tried to test the crc if it's true CRC or not
by applying the method introduced by Gregory Ewing in his article www(dot)cosc.canterbury.ac.nz/greg.ewing/essays/CRC-Reverse-Engineering.html
 Quote: Due to the superposition principle, if changing a message by xoring it with a bit pattern B1 causes its CRC to change by C1, and another bit pattern B2 causes the CRC to change by C2, then xoring the message with (B1 xor B2) should change the CRC by (C1 xor C2). If that doesn't happen, the algorithm can't be an ordinary CRC algorithm

and I found that it's a true CRC

Then I have tried all CRC8 algorithms using the program reveng : reveng(dot)sourceforge(dot)net/
It failed to find the algorithm , may be I miss using the program ?

NOTE : We don't have spectial bit messages ( 1 bit set message or all zero message )

Here are some samples of messages and CRC
first 2 bits are ID
second 2 bits are CRC
third 2 bits are the counter
the rest of bits are data
for example this message :
 Code: ID CRC  CNTR  DATA 20  67  CD    410C0000 ID is 20 CRC is 67 Counter is CD

and the rest of bits are data
if next message is
 Code: 20DDCE410C0000

note that counter CE is increased by one

 Code: 2067CD410C0000 20DDCE410C0000 2040CF410C0000 2028C0410C0000 20B5C1410C0000 200FC2410C0000 2092C3410C0000 2066C4410C0000 20FBC5410C0000 2041C6410C0000 20DCC7410C0000 771F02E0EEA7EC7 774212E0EEA7EC7 774222D0EEA7E87 77E932D0EE97E97 77BA92B0EEC7EC7 77310A2F0EEA7EC7 77B70B2F0EE97E97 77220C330EE97E97 77330D330EE97E87 77D40E330EE97E87 778C0F370EE97E87 216632000000 219AB3000000 210E38000000 21F2B9000000 21B43A000000 2148BB000000 21673C000000 219BBD000000 21DD3E000000 2121BF000000 21DC30000000 2120B1000000 1316902001900 1316582001900 131EA92001900 131660A2001900 131E90B2001900 131600E2001900 131EF0F2001900 Also we have the following (which I am not sure if it contains CRC or not ) 682

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