an apparatus and method are disclosed that provide system time base generation in a data processing system . the data processing system may have a single microprocessor or have multiple microprocessors . in either case , the data processing system has a plurality of devices that are time dependent upon the lead microprocessor within the data processing system . the apparatus includes a system clock generation circuit coupled to the microprocessor via a bus interface and a clock prescalar , further coupled to the system clock generation circuit and the bus interface , that is used to provide a clock pulse adjustment based upon a threshold count level as determined by the system clock generation circuit and the microprocessor .