UBC Theses and Dissertations
Architectures and algorithms for synthesizable embedded programmable logic cores Kafafi, Noha
As integrated circuits become more and more complex, the ability to make post fabrication changes will become more and more attractive. This ability can be realized using programmable logic cores. Currendy, such cores are available from vendors in the form of a "hard" layout. In this thesis, we focus on an alternative approach: vendors supply a synthesizable version of their programmable logic core (a "soft" core) and the integrated circuit designer synthesizes the programmable logic fabric using standard cells. Although this technique suffers increased speed, density and power overhead, the task of integrating such cores is far easier than integrating "hard" cores into an ASIC. For very small amounts of logic, this ease of use may be more important than the increased overhead. This thesis presents three synthesizable programmable logic core architectures. The place and route algorithms developed for the various architectures are also described. These algorithms have been integrated in the Versatile Place and Route (VPR) CAD tool, a widely used CAD tool for FPGA architectural studies. We compare the architectures to each other, and to a "hard" programmable logic core. We also show how these cores can be made more efficient by creating a non-rectangular architecture, an option not available to "hard" core vendors. Finally, we evaluate various approaches to improve the area performance of our architectures by considering several architectural enhancements.
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