To determine the occurrence of an address for a defective memory, cell in
a ROM, an error-correction control system includes a comparator that
compares a set of incoming memory address signals with static signals
provided by a laser-fuse array. The static signals represent addresses of
defective memory cells in the ROM. An ADDHIT signal indicates that the
ROM has received an address of a defective memory cell. The ADDHIT signal
is then timed to provide a REV signal that changes the polarity of the
memory bit signal out of a buffer circuit. This corrects an erroneous
memory cell by reversing the sense of the memory bit received from a
defective memory cell and delivered to an output terminal of the ROM. The
REV signal is steered to an output buffer corresponding to the proper ROM
chip output pad using a fuse-controlled selection circuit. A plurality of
defective memory cells are corrected by using a number of comparators to
compare input address signals to a number of fuse-controlled static
addresses, each representing a defective memory cell.