Designing Run-Time Reconfigurable Systems with JHDL

Run-time reconfigurable (RTR) systems are FPGA-based systems that reconfigure FPGAs during execution to alter hardware organization and composition to meet the varying needs of applications as they execute. These systems are difficult to describe with conventional tools (schematic capture, VHDL synthesis, etc.) because most tools assume that the underlying hardware organization is static. JHDL is a Java-based design environment capable of describing, netlisting, simulating and executing complex, dynamic RTR systems. Using conventional Java syntax, users describe hardware structures as objects; as these hardware-object constructors are invoked, JHDL automatically configures hardware circuits onto FPGA hardware, thus directly supporting the dynamic nature of RTR systems with standard language constructs. JHDL also supports codesign of the software and hardware parts of the system; in other words, the entire application can be described in a single piece of Java code that can be co-simulated/co-executed with the FPGA hardware. To date, RTR design with JHDL has focused on the development of automated target recognition (ATR) systems, and working systems described in JHDL have been demonstrated.