Patent US 4,893,271

A microcomputer having predetermined clock pulse frequency requirements receives pulses from a multiplying type frequency synthesizer which utilizes a reference frequency less than the largest of the predetermined requirements. The synthesizer is responsive to program instructions to generate clock pulse frequencies sufficient to satisfy the requirement for immediate execution of programmed tasks. As the requirements change, the synthesizer responds to provide only the frequency required. Thus, the power dissipated by the microcomputer system is minimized.