Flash multiple-pass write with accurate first-pass write

摘要

An instruction to write to a location in the Flash memory is received. It is determining if the Flash memory exposes a level placement setting associated with defining what voltage range corresponds to what level. In the event it is determined that the Flash memory exposes a level placement setting, an accurate coarse write is performed on the location, including by configuring the level placement setting to be a first value, and after the accurate coarse write is performed on the location, a fine write is performed on the location, including by configuring the level placement setting to be a second value, in response to receiving the instruction.

主权项

1. A method, comprising:
receiving, at a Flash controller, an instruction to write to a location in a Flash memory; performing an accurate coarse write on the location, including by configuring a level placement setting, associated with defining what voltage ranges correspond to what bit values, to be a first value; and after the accurate coarse write is performed on the location:
reading the location to obtain a read-back bit value;determining if the read-back bit value is a correct bit value;in the event: (1) it is determined that the read-back bit value is not the correct bit value and (2) a voltage level stored by the location is greater than a voltage range corresponding to the correct bit value per the level placement setting being set to the first value, setting the level placement setting to be a third value, wherein the level placement setting when set to the third value causes the stored voltage level to be within the voltage range corresponding to the correct bit value; andin the event it is determined that the read-back value is the correct value, performing a fine write on the location, including by configuring the level placement setting to be a second value.