Untangling twisted nets for bus routing

Previous works of Ozdal and Wong on PCB bus routing assume matched pin ordering for both sides. But in practice, the pin ordering might be mismatched and the nets become twisted. In this paper, we propose a preprocessing step to untangle such twisted nets. We also present an algorithm to solve this untangling problem. Our algorithm produces an optimal single-detour routing scheme that rematches the pin ordering. By integrating our preprocessing step into the bus router in the work of Ozdal and Wong , we show that many routing problems that cannot be solved previously can now be solved with insignificant increase in runtime.