Encoding and decoding redundant bits to accommodate memory cells having stuck-at faults

摘要

A data storage system has a memory circuit having memory cells and a control circuit that receives data bits provided for storage in the memory cells and performs iterative encoding operations. The control circuit encodes the data bits to generate a first set of redundant bits and encoded data bits, such that the encoded data bits selected for storage in a first subset of the memory cells (e.g. largest block B1) with first known stuck-at faults have digital values of corresponding ones of the first stuck-at faults. The control circuit encodes the first set of redundant bits to generate a second set of redundant bits. The control circuit performs logic functions, e.g. bitwise XOR functions, on the second set of redundant bits and the encoded data bits to generate a third set of redundant bits, such that redundant bits in the third set of redundant bits selected for storage in a second subset of the memory cells (e.g. block B2) with second stuck-at faults have digital values of corresponding ones of the second stuck-at faults. Other embodiments relate to performing bitwise logic functions and decoding operations for decoding encoded bits to regenerate data bits.