Cyclic redundancy code generator
OwnerKevin J. Hyland, Vincent G. Gavininventors
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Abstract
A cyclic redundancy code generator for data packets without an inter-packet gap comprises a CRC generator which divides each packet by a generator polynomial of degree n wherein n and augmenting logic which divides, by the generator polynomial, the product of the intermediate remainder and the term of order n in the generator polynomial, whereby each packet is padded without zeros
Claims5
1 A method of generating cyclic redundancy code for data packets represented by multi-bit binary signals comprising the steps of
- (a) presenting said packets in a succession wherein said packets immediately follow each other without an inter-packet gap therebetween.
- (b) computing for each of said packets an intermediate remainder by dividing said packet by a generator polynomial of degree n wherein n is a selected integer.
- (c) computing a final remainder by dividing, by the generator polynomial, the product of the intermediate remainder and the term of order n in the generator polynomial,
- whereby each packet is padded out with zeros by said computing step (c)
2 A method according to claim 1 wherein the presenting step (a) comprises presenting said packets each in segments consisting of multiplicity of parallel data bytes in an intermediate succession and the computing steps (b) and (c) comprise performing a multiplicity of exclusive-OR operations in respect of selected bits of the said data bytes and said intermediate remainder
3 A generator for the generation of cyclic redundancy code and inter-packet gaps for a succession of data packets, comprising
- (i) means for presenting said immediate succession of packets, each in segments consisting of a multiplicity of parallel data bytes,
- (ii) at least one cyclic redundancy code generator which includes a register for holding an intermediate remainder and which performs polynomial division of each of the segments by a generator polynomial of degree n where n is a selected integer, and
- (iii) augmenting logic disposed downstream of said register for forming a final remainder, said augmenting logic dividing by the generator polynomial the product of the intermediate remainder and the term of order n in the generator polynomial
4 A generator according to claim 3 wherein said cyclic redundancy code generator includes at least one array of exclusive-OR for performing said polynomial division
5 A generator according to claim 4 wherein said augmenting logic comprises an array of exclusive-OR gates