Constant time reference for OS support in different frequency modes

摘要

A method for providing a constant time reference to an operating system includes inputting a PCI clock and inputting a CPU clock. The method outputs a signal having a constant frequency which is a factor of the PCI clock and synchronized with the CPU clock. The method further involves using the output signal as the time reference for the operating system. The method provides a way by which the operating system can perform necessary tasks based on a constant time reference when the CPU clock is changing due to system power conservation requirements.