AN EXACT SOLUTION TO THE FITTING PROBLEM IN THE APPLICATION SPECIFIC STATE MACHINE DEVICE
Marek A. Perkowski, Malgorzata Chrzanowska-Jeske, Edmund Pierzchala, A. Coppola · Journal of Circuits Systems and Computers · 1994
In this paper the fitting problem for a new Application Specific State Machine Device, CY7C361, from Cypress Semiconductor is formulated and the solution is proposed. This fitting problem consists of mapping a netlist obtained from high-level synthesis into the chip’s physical resources. In general, a mapping (fitting) problem can be formulated as one of the labeled graph isomorphism between the netlist graph and the subgraph of the resources graph. However, the specific architecture-related constraints of the CY7C361 device cause the fitting problem to be generalized as a graph isomorphism problem with some additional mapping constraints and node multiplication (placing some nodes of the netlist graph in more than one node of the physical graph). Such formulation is quite general for a class of Complex Programmable Logic Device (CPLD) fitting problems, and has not been found in the literature. We implemented an exact, constraint-based, tree searching algorithm with several kinds of backtracking.