bch pre-search circuit, bch decoding circuit, bch pre-search method and bch error correction method

Abstract

The invention provides a BCH pre-search circuit, a BCH decoding circuit, a BCH pre-search method and a BCH error correction method. The BCH pre-search circuit comprises an empty search code length calculation circuit used for calculating the code length of an empty search according to the BCH standard code length and the BCH truncation code length; a first adjustment factor calculation circuit provided with a first finite-domain multiplier, and used for calculating a first adjustment factor according to each numerical value of the code length of an empty search and an adjustment constant; a subsequent adjustment factor calculation circuit provided with a second finite-domain multiplier and used for calculating according to the first adjustment factor; and an error position polynomial multiplication circuit provided with a third finite-domain multiplier and used for respectively multiplying each of an error position polynomial by the corresponding first adjustment factor or the subsequent adjustment factors. The BCH decoding circuit is provided with the above BCH pre-search circuit. The BCH pre-search method is implemented through the above BCH pre-search circuit. according to the invention, the area of the chip of the BCH decoding circuit can be greatly reduced.

Description

technical field [0001] The present invention relates to the field of BCH error correction coding and decoding, and specifically provides a BCH pre-search circuit, a BCH decoding circuit capable of pre-searching a BCH truncated code with any code length, a BCH pre-search method, and a BCH error correction method . Background technique [0002] In the control chip of large-capacity storage devices such as NandFlash, write errors or read errors may occur when data is written into the storage unit. Wrongly written as the binary number "1". In order to avoid writing or reading wrong data, it is necessary to verify the data. The usual practice is to write a part of redundant data artificially for error control after writing the data, so as to ensure that the data can be read incorrectly. detection and correction. [0003] The BCH error correction code is a cyclic check code usually used to correct random errors. The check code was jointly proposed by R.C.Bose, D.K.Chaudhuri and...

AI Technical Summary

Problems solved by technology

Moreover, when the shortened code length L is different, t different coefficients need to be stored. If there are y types of shortened code lengths L, then the total number of coefficients that need to be stored will be as high as y×t

[0006] However, in the current large-capacity storage devices such as Flash, the number of bits t to be corrected by the BCH error correction code is usually greater than 70, resulting in a very large circuit for pure combinational logic to complete all finite field multiplications at one time

Moreover, in order to adapt to the error correction requirements of various flashes, the number of bits t to be corrected will be different, and the data length will also be different. Therefore, it is usually necessary to support hundreds of different shortened code lengths L, so the number of adjustment factors will exceed 7000

However, since the area of ​​the chip is limited, it is impossible to adjust the factor α for all different code lengths L ~α tL All are stored in the chip, which causes the BCH decoder to pre-search only a limited number of code lengths, seriously affecting the decoding speed of the BCH decoder

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