Routing Topology and Time-Division Multiplexing Co-Optimization for Multi-FPGA Systems

Time-division multiplexing (TDM) is widely used to overcome bandwidth limitations and thus enhances routability in multi-FPGA systems due to the shortage of I/O pins in an FPGA. However, multiplexed signals induce significant delays. To evaluate timing degradation, nets with similar criticalities are often grouped to form NetGroups. In this paper, we propose a framework concerning routing topology and time-division multiplexing co-optimization for multi-FPGA systems. The proposed framework first generates high-quality topologies considering Net-Group criticalities. Then, inspired by column generation, TDM ratio assignment is solved optimally by Lagrangian relaxation. Experimental results show that our approach outperforms the top three entries of ICCAD 2019 CAD Contest. Moreover, our TDM ratio assignment algorithm can further improve the results of the top three winners to almost as good as ours.