A novel Globally Asynchronous Locally Synchronous (GALS) technique applicable to datapath architectures is presented. It is based on a request-driven operation of locally synchronous blocks. Inactivity of the request line is detected with a special time-out circuitry. When time-out occurs, clocking of the locally synchronous block is handed over to a local ring oscillator. Based on this concept, a practical hardware implementation of an asynchronous wrapper is proposed. The simulation results presented demonstrate the potential and performance of the proposed GALS architecture.