Low-Level Flexible Architecture with Hybrid Reconfiguration for Evolvable Hardware

Abstract

Field-programmable gate arrays (FPGAs) can be considered to be the most popular and successful platform for evolvable hardware. They allow one to establish and later reconfigure candidate solutions. Recent work in the field of evolvable hardware includes the use of virtual and native reconfigurations. Virtual reconfiguration is based on the change of functionality by hardware components implemented on top of FPGA resources. Native reconfiguration changes the FPGA resources directly by means provided by the FPGA manufacturer. Both of these approaches have their disadvantages. The virtual reconfiguration is characterized by lower maximal operational frequency of the resulting solutions, and the native reconfiguration is slower. In this work, a hybrid approach is used merging the advantages while limiting the disadvantages of the virtual and native reconfigurations. The main contribution is the new low-level architecture for evolvable hardware in the new Zynq-7000 all-programmable system-on-chip. The proposed architecture offers high flexibility in comparison with other evolvable hardware systems by considering direct modification of the reconfigurable resources. The impact of the higher reconfiguration time of the native approach is limited by the dense placement of the proposed reconfigurable processing elements. These processing elements also ensure fast evaluation of candidate solutions. The proposed architecture is evaluated by evolutionary design of switching image filters and edge detectors. The experimental results demonstrate advantages over the previous approaches considering the time required for evolution, area overhead, and flexibility.