1 / 8

Basics of Asynchronous Logic

Basics of Asynchronous Logic. Robby Willer. What is Asynchronous Logic?. Digital system lacking a global clock signal Also known as “clockless” logic Gates and registers communicate through a request-acknowledge process known as a “handshake”

chipo
Download Presentation

Basics of Asynchronous Logic

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Basics of Asynchronous Logic Robby Willer

  2. What is Asynchronous Logic? • Digital system lacking a global clock signal • Also known as “clockless” logic • Gates and registers communicate through a request-acknowledge process known as a “handshake” • Has existed since the 1950s but has never achieved widespread use

  3. Advantages of Asynchronous Logic • Claimed lower power dissipation and improved efficiency • Improved EMI performance • More stable current from supply • Performance is not bottlenecked by worst-case delay paths and the system can, on average, run at higher frequencies

  4. Structure of Asynchronous Circuit

  5. “Handshaking” Process • Before bit is sent, sender outputs a request signal to receiver which then returns an acknowledge signal • A variety of schemes and encodings exist • May be two-phase or four-phase

  6. Asynchronous Combinatorial Circuit • Unlike in synchronous circuits, the data should be valid at all times otherwise a hazard event occurs • As is, the combinatorial circuit below contains a hazard

  7. Disadvantages of Asynchronous Logic • Additional control elements and request-acknowledge signals take up more space • Dedicated CAD tools must be used but few of these exist • Difficult to interface with synchronous systems • As the behavior of the system can be affected by ambient conditions such as temperature and supply voltage, debugging can be extremely challenging

  8. References • Borkar, Shekhar. (2003). Does asynchronous logic design really have a future?. EE Times. • Hauck, Scott. (1995). Asynchronous Design Methodologies: An Overview. IEEE, Vol. 83, No. 1, pp. 69-93. • Jayasekar, Sathish. (2011). Low Power Digital Design using Asynchronous Logic. San Jose State University. • Nowick, Steven & Singh, Montek. (2011). High-Performance Asynchronous Pipelines: An Overview. IEEE Design & Test of Computers. • Sparso, Jens. (2006). Asynchronous Circuit Design: A Tutorial. Technical University of Denmark. • Sparso, Jens & Furber, Steve. (2001). Principles of Asynchronous Circuit Design. Technical University of Denmark.

More Related