Recursive Implementation of VLSI Circuits

This is an introduction for Escher——the geometrical layout system.An Escher circuit description is a hierarchical structure composed of cells,wires,connectors between wires,and pins that connect wires to cells.Cells may correspond to primitive circuit elements,or they may be defined in terms of lower level subcells.Unlike other geometrical layout systems,a subcell may be instance of the cell being defined.When such a recursive cell definition is instantiated,the recursion is unwound in a manner reminiscent …