A testability strategy for silicon compilers

The authors present a testability strategy for complex VLSI devices which is implemented in the PIRAMID Digital Signal Processor Silicon Compiler. The macrotest methodology supports built-in self-test, scan test, bus test control, restricted partial scan and test control logic at various levels in the design hierarchy. A set of testability design rules is developed and implemented automatically in the design. The design hierarchy is closely followed, resulting in a hierarchical set of testable macros. The complete process from design to final test program is guided by software tools. As an example, the synthesis of a large industrial circuit is presented for comparing the proposed approach with the traditional approaches. The additional overhead due to testability is within reasonable limits (roughly 8%), and the software run time figures show that it is possible to generate a test program with an excellent fault coverage within a very short period of time