Digital Design Using VHDL A Systems Approach

This book is intended to teach an undergraduate student to understand and design digital systems. It teaches the skills needed for current industrial digital system design using a hardware description language (VHDL) and modern CAD tools. Particular attention is paid to systemlevel issues, including factoring and partitioning digital systems, interface design, and interface timing. Topics needed for a deep understanding of digital circuits, such as timing analysis, metastability, and synchronization, are also covered. Of course, we cover the manual design of combinational and sequential logic circuits. However, we do not dwell on these topics because there is far more to digital system design than designing such simple modules.

Upon completion of a course using this book, students should be prepared to practice digital design in industry. They will lack experience, but they will have all of the tools they need for contemporary practice of this noble art. The experience will come with time.

This book has grown out of more than 25 years of teaching digital design to undergraduates (CS181 at Caltech, 6.004 at MIT, EE121 and EE108A at Stanford). It is also motivated by 35 years of experience designing digital systems in industry (Bell Labs, Digital Equipment, Cray, Avici, Velio Communications, Stream Processors, and NVIDIA). It combines these two experiences to teach what students need to know to function in industry in a manner that has been proven to work on generations of students. The VHDL guide in Appendix B is informed by nearly a decade of teaching VHDL to undergraduates at UBC (EECE 353 and EECE 259).

We wrote this book because we were unable to find a book that covered the system-level aspects of digital design. The vast majority of textbooks on this topic teach the manual design of combinational and sequential logic circuits and stop. While most texts today use a hardware description language, the vast majority teach a TTL-esque design style that, while appropriate in the era of 7400 quad NAND gate parts (the 1970s), does not prepare a student to work on the design of a three-billion-transistor GPU. Today's students need to understand how to factor a state machine, partition a design, and construct an interface with correct timing. We cover these topics in a simple way that conveys insight without getting bogged down in details.