Implementation-Independent Functional Test for Transition Delay Faults in Microprocessors

We propose a method for synthesis of Software-Based Self-Test (SBST) for testing RISC type of microprocessors without needing the knowledge of implementation details. The test covers a large class of faults and a special target is to detect Transition Delay Faults (TDF). To reduce the complexity, the processor is partitioned into Modules Under Test (MUT), and each MUT is in turn partitioned into data and control parts. For the data parts, pseudo-exhaustive tests are applied, whereas for the control parts a novel functional control fault model was developed. The test is regular, represented in a compact form allowing easy unrolling during test execution. Experimental results demonstrate high Stuck-At Fault (SAF) and TDF coverage, despite the lack of knowledge of implementation details.