Today's Field Programmable Gate Array (FPGA) research community could use an extensible tool flow enabling designers to examine new algorithms and new methods of interacting with FPGA configurations. One such flow is JHDLBits, which integrates two prominent FPGA design environments: JHDL and JBits. JHDLBits offers the low-level access and control provided by JBits with the high-level structural circuit design of JHDL. Furthermore, the JHDLBits flow provides greater control of resource manipulation, placement, and routing, and gives researchers a sandbox to explore advanced interactions with FPGA configurations. This thesis presents the overall architecture of the open-source JHDLBits project. Details are provided on how the core components -- JHDL, JBits3 for Virtex-II, the ADB connectivity database, and VTsim, a Virtex-II device simulator -- are linked together to provide an integrated design environment. Strategies and philosophies of the open source movement are also examined to successfully establish the support for and involvement of the FPGA research community throughout the JHDLBits open source endeavor. / Master of Science

In the realm of FPGAs, many tool vendors offer behaviorally-based simulators aimed at easing the complexity of large FPGA designs. At times, a behaviorally-modeled design does not work in hardware as expected or intended. VTsim, a Virtex-II device simulator, was designed to resolve this and many other design problems by providing a window into the FPGA fabric via a virtual device. VTsim is an event-driven device simulator modeled at the CLB level with multiple clock domain support. Utilizing JBits3 and ADB, VTsim enables simulation and examination of all resources within an FPGA via a virtual device. The only input required by VTsim is a bitstream, which can be generated from any tool suite. The simulator is part of the JHDLBits open-source project, and was designed for rapid response, low memory usage, and ease of interaction. / Master of Science