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

A data storage system comprising:

• a memory circuit comprising memory cells;
• and
• a control circuit to receive encoded bits read from the memory cells, wherein the encoded bits accommodate stuck-at faults in the memory cells,
• wherein the control circuit performs bitwise logic functions on first sets of the encoded bits to generate first intermediate bits, wherein the control circuit is performs the bitwise logic functions on second sets of the encoded bits to generate second intermediate bits, wherein each of the second sets has more bits than each of the first sets,
• wherein the control circuit decodes the second intermediate bits using the first intermediate bits to generate first decoded bits, and wherein the control circuit decodes a first subset of the encoded bits using the first decoded bits to generate decoded data bits.

A method performed by a data storage system, the method comprising:

• receiving data bits that are provided for storage in memory cells of a memory circuit in the data storage system;
• encoding 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 with first stuck-at faults have digital values of corresponding ones of the first stuck-at faults;
• encoding the first set of redundant bits to generate a second set of redundant bits;
• and
• performing logic 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 with second stuck-at faults have digital values of corresponding ones of the second stuck-at faults.

A method performed by a data storage system, the method comprising:

• receiving encoded bits read from memory cells of a memory circuit in the data storage system, wherein the encoded bits accommodate stuck-at faults in the memory cells;
• performing bitwise logic functions on first sets of the encoded bits to generate first intermediate bits;
• performing bitwise logic functions on second sets of the encoded bits to generate second intermediate bits, wherein each of the second sets has more bits than each of the first sets;
• decoding the second intermediate bits using the first intermediate bits to generate first decoded bits;
• and
• decoding a first subset of the encoded bits using the first decoded bits to generate decoded data bits.