Built-in self-testing of micropipelines

An asynchronous ARM6 microprocessor (AMULET1), designed at the University of Manchester using a two-phase signalling protocol, and the latest release of the AMULET2e embedded controller implemented using four-phase signalling, have proved the practical feasibility of the micropipeline design approach. A built-in self-test (BIST) micropipeline design based on an asynchronous BILBO register is presented in this paper. All the stage registers of the micropipeline are implemented using the proposed asynchronous BILBO register which can operate in four modes: normal operation, shift, linear feedback shift register (LFSR) and signature analyser mode. The test procedure described in this paper provides for the detection of all single stuck-at faults in the micropipeline. It is shown that delay faults in the combinational logic blocks of the BIST micropipeline can be tested by using BLBO registers of a doubled size