A new approach to the pin assignment problem

A study, motivated by the goal of integrating the placement and routing steps in the physical design of VLSI circuits, of the pin assignment problem for macrocells is discussed. It is assumed that the macrocells have already been placed. It is also assumed 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 to determine how the pins are to be shifted so that the weighted sum of the lengths of the connecting wires is minimal is developed. Good experimental results were obtained