| With the advent of LSI and VLSI technology, the demand and affordability of custom tailored design has increased considerably. A short turnaround time is desirable along with more credible testing techniques. For a low-production device it is necessary to reduce the time and money spent in the design process. Traditional hardware design automation techniques rely on extensive engineer interaction. A detailed description of the circuit to be manufactured must be entered manually. It is often necessary to prepare a separate description for each phase of the design process. In order to be successful, a modern design automation system must be capable of supporting all phases of design activities from a single circuit description. It must also provide an adequate level of abstraction so that the circuit may be described conveniently and concisely. Such abstraction is provided by computer hardware description languages (CHDL). In this research, an automation system based on AHPL (A Hardware Programming Language) has been developed. The project may be divided into three distinct phases: (1) Upgrading of AHPL to make it more universally applicable; (2) Implementation of a compiler for the language; and (3) Illustration of how the compiler may be used to support several phases of design activities. Several new features have been added to AHPL. These include: application-dependent parameters, multiple clocks, asynchronous results, functional registers and primitive functions. The new language, called Universal AHPL, has been defined rigorously. The compiler design is modular. The parsing is done by an automatic parser generated from the SLR(1) BNF grammar of the language. The compiler produces two data bases from the AHPL description of a circuit. The first one is a tabular representation of the circuit, and the second one is a detailed interconnection linked list. The two data bases provide a means to interface the compiler to application-dependent CAD systems. In the end, a discussion on how the AHPL compiler can be interfaced to other CAD systems is given, followed by examples from current applications and from ongoing research projects. These applications illustrate the usefulness of a CHDL-based approach to the design of digital hardware automation systems. |
