Asynchronous VLSI and Architecture
Cornell University

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The group is moving to Yale in January 2017.



Asynchronous Field-Programmable Gate Arrays (AFPGAs)

Asynchronous FPGA Test chip
 
Raspberry Pi with a recent AFPGA test board


Efficient pipelining support is important for FPGAs to attain high performance. We have developed two asynchronous FPGA architectures that have integrated pipelining support and that are configurable at the pipeline-stage level. A designer using these FPGAs need only think of the computation in terms of its dataflow graph, and need not be concerned with the detailed asynchronous circuit implementation.

These coarse-grain asynchronous FPGAs do not need explicit retiming registers to support pipelining, since our asynchronous FPGA has the property of slack elasticity. The net result is an efficient, high-performance FPGA architecture that is (for the first time) competitive with custom asynchronous logic.

Our design supports the use of standard clocked place-and-route tools, and we have also developed a logic synthesis method for automatically mapping asynchronous designs to our architecture.

We are also exploring the impact of 3D integration on the design of asynchronous FPGA architectures.

Students

David Fang (Ph.D. 2008)
Benjamin Hill (Ph.D. 2015)
Robert Karmazin (Ph.D. 2015)
Sean Ogden
Song Peng (Ph.D. 2006)
John Teifel (Ph.D. 2004)

Publications

Carlos Tadeo Ortega Otero, Jonathan Tse, Robert Karmazin, Benjamin Hill, and Rajit Manohar. Automatic Obfuscated Cell Layout for Trusted Split-Foundry Design. IEEE International Symposium on Hardware-Oriented Security and Trust, May 2015.

Benjamin Hill, Robert Karmazin, Carlos Tadeo Ortega Otero, Jonathan Tse, and Rajit Manohar. A Split-Foundry Asynchronous FPGA. Proceedings of the IEEE Custom Integrated Circuits Conference (CICC), September 2013. (abstract, pdf)

Christopher LaFrieda, Benjamin Hill, and Rajit Manohar. An Asynchronous FPGA with Two-Phase Enable-Scaled Routing. Proceedings of the 16th IEEE International Symposium on Asynchronous Circuits and Systems (ASYNC), May 2010. (abstract, pdf)   — Best paper finalist

S. Ramaswamy, L. Rockett, D. Patel, S. Danziger, R. Manohar, C. Kelly, J. Holt, V. Ekanayake, D. Elftmann. A Radiation Hardened Reconfigurable FPGA. Proceedings of the IEEE Aerospace Conference, March 2009. (abstract, pdf)

Rajit Manohar, Clinton Kelly IV, et al. Development of Reprogrammable Low Power High Density High Speed RADHARD FPGAs. Government Microcircuit Applications and Critical Technology Conference, March 2007.

Rajit Manohar. Reconfigurable Asynchronous Logic. Proceedings of the IEEE Custom Integrated Circuits Conference (CICC), September 2006. (abstract, pdf)

David Fang, Christopher LaFrieda, Song Peng, and Rajit Manohar. A 3-Tier Asynchronous FPGA. Proceedings of the 23rd International VLSI/ULSI Multilevel Interconnection Conference (VMIC), September 2006. (abstract, pdf)

Rajit Manohar, Clinton Kelly IV, J. Holt, Chris Liu, Leonard Rockett, Dinu Patel, Steven Danzinger. Application of Low Power High Density Gigahertz Speed Commercial FPGA Technology to High Radiation Applications using RADHARD-by-Process Techniques. Proceedings of the 9th Military and Aerospace Programmable Logic Devices International Conference, September 2006.

David Fang, John Teifel, and Rajit Manohar. A High-Performance Asynchronous FPGA: Test Results. 2005 IEEE Symposium on Field-Programmable Custom Computing Machines (FCCM), April 2005. (abstract, pdf)

Song Peng, David Fang, John Teifel, and Rajit Manohar. Automated Synthesis for Asynchronous FPGAs. 13th ACM International Symposium on Field Programmable Gate Arrays (FPGA), February 2005. (abstract, pdf, ps)

John Teifel and Rajit Manohar. An Asynchronous Dataflow FPGA Architecture. IEEE Transactions on Computers (special issue on field-programmable logic), November 2004. (abstract, pdf)

John Teifel and Rajit Manohar. Static Tokens: Using Dataflow to Automate Concurrent Pipeline Synthesis. Proceedings of the 10th IEEE International Symposium on Asynchronous Circuits and Systems (ASYNC), April 2004. (abstract, pdf, ps)

John Teifel and Rajit Manohar. Highly Pipelined Asynchronous FPGAs. 12th ACM International Symposium on Field-Programmable Gate Arrays (FPGA), Monterey, CA, February 2004. [Please see abstract]. (abstract, pdf, ps)

John Teifel and Rajit Manohar. Programmable Asynchronous Pipeline Arrays. Proceedings of the 13th International Conference on Field Programmable Logic and Applications (FPL), pp. 345--354, Lisbon, Portugal, September 2003. (abstract, pdf, ps)



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