Read-only-memory (ROM) having a memory cell that stores a plurality of bits of information

摘要

A column of read-only-memory (ROM) cells is programmed to store two or more bits of information in each cell by forming a plurality of coding (bit) lines adjacent to the column of cells, and selectively connecting the cells to the plurality of coding lines so that the different logic conditions defined by the two or more bits are represented by the coding lines that are connected to a memory cell.