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LibCRC API Reference – crc_modbus()

crc_modbus( input_str, num_bytes );


Parameter Type Description
input_str const unsigned char * The input byte buffer for which the CRC must be calculated
num_bytes size_t The number of characters in the input buffer

Return Value

Type Description
uint16_t The resulting CRC value


The function crc_modbus() calculates a 16 bit CRC value of an input byte buffer based on the CRC calculation algorithm used by the Modbus protocol. The buffer length is provided as a parameter and the resulting CRC is returned as a return value by the function. The size of the buffer is limited to SIZE_MAX.

The Modbus CRC calculation uses the same polynomial as the standard CRC-16, but with a different initialization value.

See Also