PSEUDO RANDOM AND COMMAND DRIVEN BIT COMPENSATION FOR THE CYCLING EFFECTS IN FLASH MEMORY AND METHODS THEREFOR

摘要

Easily implemented randomization within a flash memory EEPROM reduces the NAND string resistance effect, program disturbs, user read disturbs, and floating gate to floating gate coupling that result from repeated and long term storage of specific data patterns. The randomization may be code generated pseudo randomization or user driven randomization in different embodiments. User driven commands, the timing of which cannot be predicted may be used to trigger and achieve a high level of randomization. Randomly altering the encoding scheme of the data prevents repeated and long term storage of specific data patterns. Even if a user wishes to store the same information for long periods, or to repeatedly store it, it will be randomly encoded with different encoding schemes, and the data pattern will therefore be varied.