Read-only memory device and related method of design

摘要

A ROM comprises several bit output lines and X address decode lines, and stores a data set. Each address decode line stores a unique data word. Addresses in the data set that have the same data word are mapped by the decoder to the same address decode line. Each address decode line is electrically connected to a bit output line as determined by the data set. An initial design of the ROM uses N connecting devices to respectively electrically connect N of the address decode lines to a bit output line. If N exceeds X/2, then an optimization process is performed. The optimization process involves electrically disconnecting each address decode line that was connected to the bit output line, and electrically connecting each address decode line that was not connected to the bit output line. The output of the bit output line is then run through a logical inverter to provide the correct output data bit.