13189402

Paragraph Number

288

In one embodiment, the direction module 406 determines a direction of deviation for a grouping of multi-level storage cells based on a data set that includes data from one or more lower pages of the multi-level storage cells. Because the lower pages include the LSBs, in certain embodiments, the direction module 406 determines that a read voltage threshold 662 deviates toward a larger read voltage in response to a difference between a read bias for the lower pages and a known bias for the lower pages indicating that storage cell values for the LSBs have transitioned from a binary one to a binary zero. For an LSB to transition from a binary one to a binary zero, a read voltage for a multi-level storage cell using the encoding model of FIG. 6C must drift from either an L0 or L1 state to an L2 or L3 state, indicating that one or more of the read voltage thresholds 662 should be increased, to place the read voltage back in the original L0 or L1 state.

Added by DJM 3 2021