| 摘要 |
PROBLEM TO BE SOLVED: To improve error correction capability in a semiconductor storage device, having a large number of memory chips mounted thereon.SOLUTION: A semiconductor storage device generates a CRC (cyclic redundancy check) code from original data, generates a BCH (Bose-Chaudhuri-Hocquenghem) code to the original data and the CRC code, and records the original data, the CRC code, and the BCH code in one page selected from different planes of the plurality of memory chips. The semiconductor storage device generates an RS code from the original data across pages, generates a CRC code to the RS code, generates a BCH code to the RS code and the CRC code, and records the RS code, the CRC code, and the BCH code into a memory chip different from the original data. When performing reading, the semiconductor storage device performs error correction to the original data by the BCH code, and thereafter calculates CRC. If the number of errors is the number for allowing erasure correction by the RS code, the semiconductor storage device performs the erasure correction to the original data. If the number of the errors exceeds the erasure correction capability in the RS code, the semiconductor storage device performs normal error correction by the RS code, and also performs error correction by the BCH code. |
