A Comparison of Self-Timed Design using FPGA, CMOS, and GaAs Technologies

Asynchronous or self-timed systems that do not rely on a global clock to keep system components synchronized can offer significant advantages over traditional clocked cir-cuits in a variety of applications. One advantage is that because of the separation of timing from functionality in these systems, the same circuit may be implemented in a variety of technologies without modification to the circuit. In this paper we explore one approach to self-timed de-sign and describe implementations of an example circuit in three different technologies. The simple routing chip used as the example has been described by writing a program in OCCAM, translated into a circuit consisting of a small set of basic modules, and implemented using Actel FPGA, CMOS, and GaAs technologies.