NanoMap: An Integrated Design Optimization Flow for a Hybrid Nanotube/CMOS Dynamically Reconfigurable Architecture

NATURE is a recently developed hybrid nano/CMOS reconfigurable architecture. It consists of complementary metal- oxide semiconductor (CMOS) reconfigurable logic and interconnect fabric, and carbon nanotube-based non-volatile on- chip configuration memory. Compared to existing CMOS- based field-programmable gate arrays (FPGAs), NATURE increases logic density by more than an order of magnitude and offers cycle-by-cycle run-time reconfiguration capability. As opposed to some other recently proposed hybrid nano/CMOS designs, which mostly rely on the not-yet-mature self-assembly fabrication process, NATURE is compatible with mainstream photolithography fabrication techniques. Thus, NATURE offers a commercially feasible technology with high performance, superior integration density, and excellent run-time flexibility. In this paper, we present an integrated design and optimization platform for NATURE, called NanoMap. Given an input design specified in register-transfer level (RTL) and/or gate-level VHDL, NanoMap optimizes and implements the design on NATURE through logic mapping, temporal clustering, placement, and routing. NATURE offers a highly- efficient computation model, called temporal logic folding. A logic circuit can be arbitrarily folded into a sequence of logic stages, which temporally share and execute on the same hardware resource using fine-grain run-time reconfiguration. To effectively leverage this feature, we propose and develop novel mapping techniques which can automatically explore and identify the best temporal logic folding configuration, targeting area, delay or area-delay product. It uses a force- directed scheduling technique to optimize and balance resource usage across different folding cycles. It provides significant design flexibility in performing area-delay tradeoffs under various user-specified constraints. Experimental results demonstrate that NanoMap can judiciously trade off area and delay, and effectively exploit the different features of NATURE.