A new approach to the pin assignment problem

A study is made of a pin assignment for macrocells, motivated by the goal of integrating the placement and routing steps in the physical design of VLSI circuits. The authors assume that the macrocells have already been placed and that the design of the macrocells is still 'soft' in that, although the pins in a cell have a fixed relative order, they can be shifted around the boundary of the cell. An algorithm is developed to determine the optimal shiftings of the pins so that a weighted sum of the lengths of the connecting wires is minimum. Good experimental results have been obtained.<>