A general and flexible switchbox router: CARIOCA

A switchbox router utilizing layers is presented. Each net is first partitioned into a set of subnets. This decomposition is driven by the minimum Steiner tree. The construction is then carried out on a step-by-step basis, which allows the system to dynamically take new information on the problem into account. The information is examined by a set of expert systems which decide which subnet should be routed next. This part has been implemented with a blackboard architecture. The router can handle pins that are not on a grid on one set of parallel edges. The program has been implemented in the LISP programming language. Many test cases have been run successfully, and some results, including Burstein´s difficult switchbox, are presented