Technology mapping algorithms for hybrid fpgas containing lookup tables and plas

S. Krishnamoorthy, R. Tessier
2003 IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems  
Programmable devices containing lookup tables (LUTs) and programmable logic arrays (PLAs) provide a heterogeneous target platform for user designs. Present commercial tools, which target these hybrid devices, require hand partitioning of user designs to isolate logic for each type of logic resource. In this paper, an automated technology mapping tool, hybridmap, is presented that identifies design logic partitions as suitable for either LUT or PLA implementation. A breadth-first search-based
more » ... graph extraction and evaluation heuristic is integrated with product term (Pterm) count, area, and delay estimators to guide the technology mapping process. Hybridmap can be adapted to target a variety of PLA architectures and can accommodate user-provided timing constraints. It is shown that when timing constrained, hybridmap reduces LUT consumption for Apex20KE devices (Altera Corporation 1999) by 8% and when unconstrained by 14% by migrating logic from LUTs to Pterm structures. Hybridmap is shown to outperform previous mapping approaches (Lin and Wilton 2001) for Apex20KE-type devices by up to 22%. Index Terms-Hybrid field-programmable gate array (FPGA), lookup table (LUT), programmable logic arrays (PLAs), technology mapping.
doi:10.1109/tcad.2003.810743 fatcat:vp4jmm4pzresfj7gtmvysfshj4