Replacement semiconductor read-only memory

摘要

A semiconductor read-only memory includes a plurality of memory cell groups each having a plurality of memory cells, a first selector for selecting an arbitrary memory cell group from the plurality of memory cell groups, and a second selector for selecting an arbitrary memory cell from the selected memory cell group. The semiconductor read-only memory further includes: an address storage circuit for storing address information of a predetermined memory cell portion in a memory cell group; a data storage circuit for storing memory cell information of the predetermined memory cell portion; and a switching circuit for switching between information stored in the memory cell selected from the memory cell group and the memory cell information stored in the data storage circuit, based on the address information, and outputting either the information stored in the memory cell selected from the memory cell group or the memory cell information stored in the data storage circuit.