Toggling known patterns for reading memory cells in a memory device

Abstract

Systems, methods, and apparatus for a memory device. In one approach, known reference patterns are stored in a memory array. The patterns are associated with codewords stored in the memory array. A first pattern has all memory cells written to a first logic state (e.g., all logic ones), and a second pattern has all memory cells written to an opposite second logic state (e.g., all logic zeros). When a controller reads a codeword, the controller first reads memory cells of the associated reference patterns to determine data for estimating a threshold voltage distribution of memory cells in the codeword. Based on a number of memory cells of the reference patterns that snap when reading the first and second patterns, the controller selects a read voltage for reading the associated codeword.