Patent ID: 9036413
Filing Date: 2015-05-19
Classification: G11C

Abstract:
1. A method for flash memory controller operation, comprising: reading data from a portion of a flash memory a plurality of times using a plurality of different candidate reference voltages, each time reading data from the portion of the flash memory using a different candidate reference voltage from all other times, the plurality of different candidate reference voltages distributed over a voltage range, the voltage range centered on an estimated mid-point between a pair of adjacent target cell voltages; determining a plurality of decision patterns, each decision pattern corresponding to a voltage region bordering one of the candidate reference voltages; counting occurrences of each of the plurality of decision patterns in the data read from the portion of the flash memory; determining one or more of the decision patterns having a minimum of occurrences; determining a cross-point voltage corresponding to a mid-point of one or more voltage regions corresponding to the one or more decision patterns determined to have a minimum of occurrences; and providing an indication of the cross-point voltage to a read data detector.