Design of Asynchronous Circuits

• Evaluate and explain whether it is advantageous to use asynchronous circuits when implementing a digital circuit for a given application, and assess the effect on the properties of the circuit (energy, speed, area, etc.).
• Implement typical handshake components using typical handshake protocols.
• Specify and design ”speed independent” control circuits using relevant design methods and CAD tools.
• Construct smaller computing circuits by manually composing so-called handshake components.
• Assess which handshake protocol is most appropriate to use in a given situation.
• Explain what it means that a circuit is ”speed independent” or ”delay insensitive”, and analyze if a given smaller (control)circuit possesses one of these properties.
• Analyze and optimize the speed of a circuit which is built from handshake components; by using qualitative reasoning and by performing quantitative calculations.
• Identify and explain the problems (synchronization and metastability) related to communicating between several clock domains, devise possible solutions and reason about the performance and reliability of these.

Motivation for using asynchronous circuits. Basic concepts, communication protocols, and circuit implementation styles. Simple circuit examples. Performance analysis: qualitatively and quantitatively (latency, wavelength, and cycle time). Fundamental theoretical concepts: classification (self-timed, speed-independent, delay-insensitive), hazards isochronic forks and arbitration. Control circuits: synthesis of speed-independent control circuits from signal transition graph specifications. Data-path circuits: design of efficient data-path circuits with completion detection/indication. Relationship between handshake protocols and circuit implementation. Design strategies/methods: static data-flow structures and compilation from asynchronous HDL’s. Globally synchronous locally synchronous systems, including digital circuits with multiple clock domains.. Synchronization when transferring data between independent clock domains. Case studies: some recent (commercial) asynchronous IC’s. Current research trends.

02203/02139, Solid background in digital electronics.

Self-study and group work driven by a project. Occasional meetings with the teacher by appointment.

The course is offered in the spring of 2024 for particularly interested students. The teaching method is self-study and groupwork driven by a project. The project can form the basis for a conference article. Occasional meetings with the teacher by appointment.