Low cost adjacent double error correcting code with complete elimination of miscorrection within a dispersion window for Multiple Bit Upset tolerant memory

Multiple Bit Upsets (MBUs) have become increasingly more frequent with continued increase in memory density. The existing adjacent error correcting codes suffer from high probability of miscorrection for non-adjacent double errors. Miscorrection of a nonadjacent double error as an adjacent double error can reduce the reliability of the memory incorporating such codes. A constraint driven methodology is proposed here for deriving an error correcting code that can correct all single errors and correct the most likely double bit errors i.e., double adjacent errors in a memory while completely eliminating the miscorrection of the most likely nonadjacent double errors. The check bit overhead is minimal and comparable to SEC-DED and SEC-DAEC codes. The encoding and decoding schemes along with the associated hardware for the proposed code are also presented.