Construction of polyvalent error control codes for multilevel memories

The introduction of the multilevel storage approach and the advances in semiconductor memory technology towards higher-density chips create new reliability challenges for the memory designer. This paper presents a method to construct polyvalent error control codes for multilevel memories, which protect data stored in memory cells working at a variable number of bits per cell. The obtainable error control scheme allows a flexible use of multilevel memories assuring required data protection by exploiting the same encoding/decoding circuit and check cells. Implementation aspects of an encoding/decoding circuit are also discussed.