Data reading method, memory control circuit unit, and memory storage device

Abstract

The invention provides a data reading method, a memory control circuit unit, and a memory storage device used in a rewritable nonvolatile memory module. The method comprises performing an error correction decoding operation on the user data string based on the error checking and correction code to generate a first decoded data string; searching for a plurality of uncorrectable sub-data units among the decoded sub-data units of the first decoded data string, selecting at least one target sub-data unit from the uncorrectable sub-data units; the target sub-data unit is adjusted in the first decoded data string to generate an adjusted user data string and an error correction decoding operation is re-performed on the adjusted user data string to generate a second decoded data string; If there is no error bit in the second decoded data string, the second decoded data string is used as the corrected data string to be sent to a host system. By means of the data reading method, the memory control circuit unit, and the memory storage device, the read data can be effectively corrected.

Description

technical field [0001] The invention relates to a data reading method for a rewritable non-volatile memory module, a memory control circuit unit and a memory storage device. Background technique [0002] Digital cameras, mobile phones, and MP3 players have grown rapidly in recent years, making consumers' demand for storage media also increase rapidly. Since the rewritable non-volatile memory module (for example, flash memory) has the characteristics of data non-volatility, power saving, small size, and no mechanical structure, it is very suitable for being built in the various memory modules listed above. in portable multimedia devices. [0003] Generally speaking, the data written to the rewritable non-volatile memory module will be encoded according to an error correction code, and the data read from the rewritable non-volatile memory module will also pass through the corresponding program to decode. However, the correction capability of the error correction code has it...

AI Technical Summary

Problems solved by technology

However, the correction capability of error correcting codes has its upper limit

For example, if the turbo code algorithm or the low-density parity-check correction code algorithm is used to implement the error correction code in an iterative manner, as the number of iterative decoding increases to a certain number, the number of error bits will vary in the subsequent iterative decoding process. decrease as the number of iterations increases

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