pin assignment of circuit cards and the routability of multilayer printed wiring backplanes
This paper examines the relationship between the pin assignment for circuit cards and the routability of the multilayer printed wiring backplane on which the cards are mounted. It is shown that the pin assignment should meet three objectives in order to facilitate backplane routing. Heuristic strategies for determining a pin assignment to attain these objectives are given. These strategies have been implemented in a program which was used in two separate experiments involving two different backplane configurations. In both cases, the use of the pin assignments obtained with the program led to major improvements in backplane routability. In one of the experiments, as a worst-case study, the most difficult circuit card was selected for a new card layout. The new layout was obtained without much difficulty; thus the pin assignment given the selected card by the program was realized. This result demonstrates that it is not as formidable a task as is sometimes believed to implement a pin assignment for circuit cards obtained by backplane considerations.
assignment circuits routing paper relationships object order heuristics strategies use experience configurability layout task case studies