Analytica GmbH AnaGate CAN duo Manuel d'utilisateur télécharger pdf (Page 81)

FAQ - Frequent asked questions

unsigned char CalcCRC( char * pBuffer, int nBufferLength )

{

int i;

unsigned char nCRC = pBuffer[2]; // skip the length bytes

// XOR over all bytes in the message except the length information and the last byte

for( i = 3; i < nBufferLength -1; i++ )

{

nCRC ^= pBuffer[i];

}

return nCRC;

}

When using the function CalcCRC the parameter pBuffer must point to the data buffer, which

contains the already created complete data telegram. The length parameter nBufferLength

depends on the created command type and can be computed as shown below:

buffer length = sizeof( command length ) + sizeof( command code )

+ sizeof( command id ) + sizeof( CRC ) + sizeof(data)

= 7 + sizeof(data)

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Analytica GmbH AnaGate CAN duo Manuel d'utilisateur Page 81