An Asynchronous Microprocessor

Doug Edwards

For: Anybody brave enough


Two circuit design design styles can be identified: synchronous in which a clock is used to separate consecutive system states from one another and asynchonous in which there is no common clock and in which states are defined in terms of input values and internal actions. Most hardware systems are synchronous because timing issues are restricted to the moment in time when the clock changes leading to ease of design. However there has recently, for a number of reasons, been in resurgence of interest in asynchronous techniques. The AMULET group within the department has developed an asynchronous version of the well-known ARM microprocessor. A second, improved, version (AMULET2e) is now complete.

This project is tackle the design of a simple asynchronous RISC microprocessor, STUMP, which in its synchronous form is used as a laboratory project for 2nd year students. The processor is a 16 bit machine with a very restricted instrcution set and lacks the complications such as an exception mechanism that normally makes life difficult for hardware designers. If successful, it is envisaged that the design could be used as a case study for undergraduate courses.