Cache test sequence for single-ported row repair CAM

摘要

The present invention incorporates built-in self test and self repair functionality into a semiconductor memory device in which reconfiguration data used to replace faulty memory is stored at the same time testing to identify other faulty memory cells continues. To avoid access contention conflicts to a content addressable memory used to identify rows or groups of rows having faulty memory cells, the built in test function writes test data to each cell at least twice before reading the stored data. By writing twice before reading, contention problems caused by simultaneous updating of the content addressable memory are avoided. That is, even if the content addressable memory is initially unavailable to process address information used to access a memory cell to be tested, repetition of the write process ensure that the data will be properly stored when the memory again becomes available after being updated.