MAPPING BETWEEN PROGRAM STATES AND DATA PATTERNS

摘要

The present disclosure includes methods and apparatuses for mapping between program states and data patterns. One method includes mapping a data pattern to a number of program state combinations L corresponding to a group of memory cells configured to store a fractional number of data units per cell. The mapping can be based, at least partially, on a recursive expression performed in a number of operations, the number of operations based on a number of memory cells N within the group of memory cells and the number of program state combinations L.

主权项

1. A method for operating a memory, comprising:
receiving an m unit data pattern to be stored in a group of N memory cells, each memory cell of the group being programmable to L program states, wherein L is a number of program states used to store m/N units of data per memory cell; assigning a particular one of a number of program state combinations of the group of N memory cells of the group of N memory cells to a corresponding m unit data pattern according to a cost-based mapping; wherein the cost-based mapping includes an associated cell frame having a length N and wherein the cost-based mapping comprises:
an index corresponding to each one of the respective number of program state combinations; anda total cost corresponding to each one of the respective number of program state combinations, and wherein the total cost is a sum of costs corresponding to the respective program states of the respective number of program state combinations, with each of the L program states having a different cost corresponding thereto;wherein, for those of the number of program state combinations having a same total cost, the index corresponding to the respective program state combinations is based on a cost comparison between program states associated with a first portion of the cell frame and program states associated with a second portion of the cell frame.