NONVOLATILE SEMICONDUCTOR MEMORY

摘要

PURPOSE:To adjust a data rewriting time by providing a register capable of setting the rewriting time. CONSTITUTION:In an EEPROM, the register 23 for setting the data rewriting time is provided in a timer part 13 and the rewriting time is set freely through a system CDU and held in the register 23. The frequency division output of a frequency divider circuit 21 is selected to which a system clock is supplied based on the holding information and the rewriting time of the EEPROM is adjusted. Thus, the data rewriting time is optimized for the characteristic fluctuation of a memory cell due to a manufacturing process and the data rewriting time is revised according to an applied system.