Embedded memory in FPGAs: recent research results

Recent dramatic improvements in integrated circuit fabrication technology have led to field-programmable gate arrays (FPGAs) capable of implementing entire digital systems. Unlike the smaller circuits that have traditionally been targeted to FPGAs, these large systems often contain memory. Architectural support for the efficient implementation of memory in next-generation FPGAs is therefore crucial. In this paper, we will describe recent research into FPGA memory architectures. We seek to uncover not only the best architecture for the memory arrays themselves, but the best architecture for their interconnection, and the interconnection of the memory architecture to the rest of the FPGA. We also show how memory arrays that are not used to implement storage can be used to implement the logic parts of circuits very efficiently. Many of the early research results have already been used in commercial FPGAs; others are likely to be used in the future.