SEMICONDUCTOR MEMORY DEVICE

摘要

PROBLEM TO BE SOLVED: To make data written in PROM's apparently reprogrammable by a method wherein, if two or more addresses identical to an inputted address exist in a 1st PROW cell array in which addresses corresponding to erroneous data of a mask ROM are stored, a data is selected and read out from a group of data stored in a 2nd memory cell array. SOLUTION: A data memory PROM cell array 5 and an address memory PROM array 9 are composed of single layer PROM's which can be manufactured by a manufacturing process identical to that of a mask ROM. A user can write data into the array with a PROM writer, etc. An address detection circuit 31 reads out a data stored in the data memory PROM cell array 5 if an inputted address signal is identical to an address stored in the address memory PROM cell array 9. If two or more identical addresses exist, a priority order circuit 32 selects a data written at the end preferentially.