A connection-based router for FPGAs

The FPGA´s interconnection network not only requires the larger portion of the total silicon area in comparison to the logic available on the FPGA, it also contributes to the majority of the delay and power consumption. Therefore it is essential that routing algorithms are as efficient as possible. In this work the connection router is introduced. It is capable of partially ripping up and rerouting the routing trees of nets. To achieve this, the main congestion loop rips up and reroutes connections instead of nets, which allows the connection router to converge much faster to a solution. The connection router is compared with the VPR directed search router on the basis of VTR benchmarks on a modern commercial FPGA architecture. It is able to find routing solutions 4.4% faster for a relaxed routing problem and 84.3% faster for hard instances of the routing problem. And given the same amount of time as the VPR directed search, the connection router is able to find routing solutions with 5.8% less tracks per channel.