A Systematic Method for Modifying March Tests for Bit-Oriented Memories into Tests for Word-Oriented Memories

Most memory test algorithms are optimized for a particular memory technology and a particular set of fault models, under the assumption that the memory is bit-oriented, i.e., read and write operations affect only a single bit in the memory. Traditionally, word-oriented memories have been tested by repeated application of a test for bit-oriented memories, whereby a different data background is used during each application. This results in time inefficiencies and limited fault coverage. A systematic way of converting tests for bit-oriented memories into tests for word-oriented memories is presented, distinguishing between interword and intraword faults. The conversion consists of concatenating to the test for interword faults, a test for intraword faults. This approach results in more efficient tests with complete coverage of the targeted faults. Word-oriented memory tests are very important, because most memories have an external data path which is wider than one bit.