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The CPWM controller is complex and has a high degree of configurability, making simulation-based verification impractical due to the large configuration space and limited time to market.

The authors propose using formal verification (FV) to exhaustively verify the design for all possible configurations and data values in a shorter time. They describe a proven formal verification approach that overcomes the limitations of traditional FV, which suffers from convergence problems for complex designs.

The design considered is a configurable pulse width modulation controller with an input interface, crossbar, waveform controllers, window qualifier, and interrupt controller. The authors explain various techniques used to reduce verification time and provide complete coverage, including formal property verification (FPV) and "one cycle design configuration," which reduces design complexity, explores all possible configurations in less time, and eliminates the need for constraints to drive correct values on the configuration bus.

By black boxing the configuration registers and putting constraints at their outputs, the authors reduced design complexity and saved time that would have been spent writing or updating these registers. This approach allowed the design to be tested for all possible values of system configurations in zero time, avoiding the effort of writing constraints to drive correct values on the configuration bus.