A programming method for multilevel analog flash memory using coarse and fine sequence

A new two-stage method for programming flash memory cells in an analog record and playback system is reported. The algorithm has a coarse and a fine portion to speed up the recording process. This method is used to store 16 minutes of audio signals, at a sampling rate of 4 kHz (or 8 minutes at 8 kHz) in a 4 Mb flash array with a resolution approaching 8-bit.