Architectural level test generation for microprocessors

Hierarchically designed microprocessor-like VLSI circuits have complex data paths and embedded control machines to execute instructions. When a test pattern has to be applied to the input of an embedded module, determination of a sequence of instructions, which will apply this pattern and propagate the fault effects, is extremely difficult. After the instruction sequence is derived, to assign values at all interior lines without conflicts is also very difficult. In this paper, we propose a separation of test generation process into two phases: path analysis and value analysis. In the phase of path analysis, a new methodology for automatic assembly of a sequence of instructions is proposed to satisfy the internal test goals. In the phase of value analysis, an equation-solving algorithm is used to compute an exact value solution for all interior lines. This new ATPG methodology containing techniques for both path and value analysis forms a complete solution for a variety of microprocessor-like circuits. This new approach has been implemented and experimented on six high-level circuits. The results show that our approach is very effective in achieving complete automation for high-level test generation