Layer Assignment of Escape Buses with Consecutive Constraints in PCB Designs

It is important for cost and reliability consideration to minimize the number of the used layers in a PCB design. In this article, given a set of n circular escape buses with their escape directions between two adjacent components and a set of m consecutive constraints on the escape buses, the problem of assigning the given escape buses between two adjacent components onto the minimized layers is first formulated for bus-oriented escape routing. Furthermore, an efficient approach is proposed to minimize the number of the used layers for the given escape buses with the consecutive constraints and assign the escape buses onto the available layers. Compared with Yan's approach [Yan and Chen 2012] for the layer assignment of the linear escape buses with no consecutive constraint and Ma's approach [Ma et al. 2011a] for the layer assignment of the circular escape buses with consecutive constraints, the experimental results show that the proposed approach obtains the same optimal results on the number of the used layers and reduces 43.6% and 90.5% of CPU time for the tested examples on the average, respectively.