Patent ID: 8402347
Filing Date: 2013-03-19
Classification: G06F,G11C,H03M

Abstract:
1. A method of storing data, the method comprising: receiving a first user data word to be stored; transforming the first user data word to a first internal data word according to a transformation function, wherein the transformation function transforms {11, 10, 01, 00} of the first user data word to {11, 10, 00, 01} of the first internal data word and transforms {11, 10, 01, 00} of the second user data word to {11, 10, 00, 01} of the second internal data word, the first user data word being the same size as the first internal data word; generating a first check word based at least in part on the first internal data word according to an error correction code (ECC) scheme; writing the first internal data word and the first check word to a plurality of unidirectional data storage cells according to an internal cell coding scheme; receiving a second user data word to be stored; transforming the second user data word to a second internal data word according to the transformation function; generating a second check word based at least in part on the second internal data word according to the ECC scheme; and without erasing the plurality of unidirectional data storage cells, writing the second internal data word and the second check word to the plurality of unidirectional data storage cells according to the internal cell coding scheme.