Architecture and CAD for FPGAs

Abstract

Long past are the days when programmable logic (FPGAs and CPLDs) were used only for prototyping and interface logic. Today's modem devices have complicated architectures with close to 200,000 logic elements and flip-flops, dedicated blocks for DSP processing, embedded memories and processors, and support many I/O standards including high-speed serial and now embedded tranceivers. The CAD software to support FPGAs has grown in sophistication and scope to support these larger, more complicated, devices and the size of software groups at FPGA vendors is now larger than all but the biggest EDA companies. Most user designs are now complete systems and go to production as an FPGA. In this tutorial we talk about recent FPGA and CPLD device architectures and CAD tools, with an emphasis on the interaction between the software and the architecture, and how this has driven recent evolutions and revolutions in PLD architecture. We also discuss the software behind the FPGA - the synthesis, place and route algorithms and CAD flow used to convert a high-level design into a bitstream to program the device. Finally, we discuss issues in designing hardware for FPGAs, including coding styles to achieve better performance and area, and effective use of dedicated resources on FPGAs.