On - Line Built - in Self - Test for Operational Faults

is fast becoming a basic feature of digital systems, not only for critical applications , but also for highly-available applications. To achieve the goals of high error coverage and low error latency, advanced hardware features for testing and monitoring must be included. One such hardware feature is built-in self-test (BIST), a technique widely applied in manufacturing testing. We present a practical on-line periodic BIST method for the detection of operational faults in digital systems. The method applies a near-minimal determinis-tic test sequence periodically to the circuit under test (CUT) and checks the CUT responses to detect the existence of operational faults. To reduce the testing time, the test sequence may be partitioned into small sequences that are applied separately—this is especially useful for real-time digital systems. Several analytical and experimental results show that the proposed method is characterized by full error coverage , bounded error latency, moderate space and time redundancy.