For a first embodiment, the state of a flash cell having n states, where n is a power of 2, is determined by selectively comparing the threshold voltage Vt of a selected memory cell to...http://www.google.com/patents/US5828616?utm_source=gb-gplus-sharePatent US5828616 - Sensing scheme for flash memory with multilevel cellsAdvanced Patent SearchPublication numberUS5828616 APublication typeGrantAppl