Semiconductor memory having memory cells and device for controlling data written in the semiconductor memory

Abstract

Each memory cell of an SRAM has normally a pair of inverters cross-connected to each other, a pair of transistors connected to output ends of the inverters respectively, a word line connected to gates of the transistors, and a bit line and an inverted bit line connected to the transistors respectively. To produce a storage data fixing memory cell functioning as that of a ROM from one normal memory cell, an input end of one inverter is disconnected from the output end of the other inverter and is connected to a low electric potential terminal or is connected to a high electric potential terminal. Therefore, preset data can be stored in the storage data fixing memory cell without changing characteristics of the SRAM in the changing of the normal cell memory to the storage data fixing memory cell.