US Patent 7920411 Converting SRAM cells to ROM cells

A method of converting a static random access memory cell to a read only memory cell and the cell thus converted is disclosed. The cell to be converted comprises a data retention portion powered by a higher and lower voltage supply line and four transistors arranged as two cross coupled inverters. It is converted to a read only memory cell by severing a connection between at least one of said transistors within a first of said two inverters and one of said voltage supply lines such that when powered said first inverter outputs a predetermined value.