| 摘要 |
PROBLEM TO BE SOLVED: To shorten the whole processing time, while improving reliability of data read from a NAND flash memory or the like by using hard-decision decoding and soft-decision decoding.SOLUTION: An error correction code decoding apparatus includes: a hard-decision decoding part 11 for executing hard-decision decoding using a signal of binary value per bit as input data and executing parity check for the input data; a soft-decision decoding part 13 for executing soft-decision decoding using a signal whose number of multiple levels per bit is larger than 2 as input data; a start-up control part 14 for controlling start-up of the hard-decision decoding part 11 and the soft-decision decoding part 13; and an output selection part 15 for selecting either one of respective output signals from the hard-decision decoding part 11 and the soft-decision decoding part 13 and outputting the selected output signal. When the number of parity errors is within an allowable value, a decoded result of the hard-decision decoding part 11 is selected and output, and when the number of parity errors exceeds the allowable value, the soft-decision decoding part 13 is started up and a soft-decision decoding result is selected and output. |
