A Tool for the Synthesis of Asynchronous Speed-Independent Circuits

The present work is devoted to the development of software tool written in Java for synthesis of asynchronous speed-independent circuits. A special type of Petri nets - Signal Transition Graph, was used for the synthesis. Using the algorithm based on the theory of regions, a logic function is derived from this graph. In order to reduce the complexity of the resulting asynchronous circuit the number of gates should be minimized by optimization of logical function with a Quine-McCluskey algorithm. Asynchronous circuits have gained in importance along with the expansion of the production of high integration circuits. By that time, mostly synchronous systems were designed. Decreasing the dimensions and increasing the operating frequency, however, made the synchronisation of individual function blocks on a chip more dif- ficult. The time delay is generally caused by the increased cycle of timing signal. This delay (for the individual function blocks) differs locally to such a degree that it results in the synchronisation failure of the individual subsystems and the malfunction of the circuit. This issue can be solved by adding a special regulation circuit providing a constant clock frequency in the whole chip. Such a circuit would occupy relatively much space on a chip (approx. 10%) and consume much power (approximately 40% of the input power). This would result in the increasing cost and energy demand of such chips. The application of asynchronous circuits provides a different approach. These circuits do not need a clock signal because their operation is controlled by events and not by time. As no clock signal generation is required and no regulation circuitry is needed, such circuits are smaller and consume less energy. The only issue that is common for both synchronous and asynchronous circuits is the presence of so- called hazardous states. The aim of this work is to provide a tool for the synthesis of asynchronous circuits that generates a circuit diagram as a result of the circuit behavior. The field of digital circuit synthesis is complex and provides many solution approaches. One of them is represented by the application of the Petri nets formalism as a description tool for the behavior of an arbitrary digital circuit. Application of algorithms for STG synthesis