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# Investigating Error Detection using CRC EE800 Project Presentation

Investigating Error Detection using CRC EE800 Project Presentation V ISHESH 11089943. Introduction. CRC generation is mostly implemented using Linear feedback shift Registers using Flip-Flops and XOR gates.

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## Investigating Error Detection using CRC EE800 Project Presentation

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1. Investigating Error Detection using CRC EE800 Project Presentation VISHESH 11089943

2. Introduction CRC generation is mostly implemented using Linear feedback shift Registers using Flip-Flops and XOR gates. But not many understand how to implement a customized parallel CRC circuit described by an arbitrary CRC generator polynomial. In this paper importance of parallel architecture is discussed and how it can be incorporated in different styles so as to compare the number of logic cells used for each Architecture.

3. Serial CRC Implementation USB CRC5 implementation as LFSR using generator polynomial G(x)=x5+x2+1 The problem is that in many cases shift register implementation is suboptimal. It only allows the calculation of one bit every clock. If a design has 16-bit wide data path, meaning that every clock CRC module has to calculate CRC on 16-bit of data, this scheme will not work.

4. Parallel CRC Generator Every clock N bits are processed. Parallel CRC Generator M-Bit CRC next state M-Bit CRC Output N-Bit Data input EXAMPLE OF USB CRC5 with N=4, M=5 @ [1],[2],[5]

5. USB CRC5 with N=4 the parallel CRC equations Mout[0] = Min[1] ^ Min [4] ^ Nin[0] ^ Nin [3] Mout [1] = Min [2] ^ Nin [1] Mout [2] = Min [1] ^ Min [3] ^ Min [4] ^ Nin [0] ^ Nin [2] ^ Nin [3] Mout [3] = Min [2] ^ Min [4] ^ Nin [1] ^ Nin [3] Mout [4] = Min [0] ^ Min [3] ^ Nin [2] Mout is the parallel CRC implementation.

6. #1 CRC CHECKER DATA* + CRC CRC REGISTER CRC PARALLEL CRC GENERATION CRC DATA(7:0) DATA BUFFER DATA(7:0)* ERROR NO ERROR

7. #2 CRC COMPARATOR CRC REGISTER PARALLEL CRC GENERATOR CRC PRE CALCULATED CRC DATA(7:0) CRC* DATA BUFFER DATA(7:0)* ERROR NO ERROR

8. #3 CRC COMPARATOR CRC REGISTER PARALLEL CRC GENERATOR CRC PARALLEL CRC GENERATOR DATA(7:0) CRC* DATA BUFFER ERROR NO ERROR DATA(7:0)*

9. Example based for #3 0X8041 COMPARATOR CRC REGISTER PARALLEL CRC GENERATOR 0x8041 PARALLEL CRC GENERATOR 0X1F 0X8261 DATA BUFFER ERROR ‘1’ NO ERROR 0XEF

10. Results Parallel/LUT CRC Generation Block

11. Comparison CRC COMPARATOR CRC REGISTER CRC CHECKER DATA* + CRC CRC REGISTER CRC PARALLEL CRC GENERATION PARALLEL CRC GENERATOR CRC CRC PARALLEL CRC GENERATOR DATA(7:0) DATA(7:0) CRC* DATA BUFFER DATA BUFFER ERROR NO ERROR DATA(7:0)* DATA(7:0)* ERROR NO ERROR

12. References [1] G. Campobello, G Patane, M Russo, “Parallel CRC Realization” (http://ai.unime.it/~gp/publications/full/tccrc.pdf) [2] G.Albertango and R. Sisto, “Parallel CRC Generation”, IEEE Micro, Vol. 10, No. 5, October 1990, pp. 63-71. [3] A. Perez, “Byte-wise CRC Calculations”, IEEE Micro, Vol. 3, No. 3, June 1983, pp. 40-50 [4] Adrian Simionescu, Nobug Consultinghttp://space.ednchina.com/upload/2008/8/27/5300b83c-43ea-459b-ad5c-4dc377310024.pdf • [5]EvgeniStavinov, 2010 issue of Circuit Cellar magazine, Page 40. [6] R. J. Glaise, “A two-step computation of cyclic redundancy code CRC-32 for ATM networks”, IBM Journal of Research and Development Volume 41 , Issue 6 (November 1997) pp 705 - 710

13. THANK YOU

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