2008 Volume 1 Pages 48-57
Generally, there are periodic interrupt services such as periodic clock tick interrupts in the real-time embedded systems even though the system is in the idle state. To minimize the power consumption of idle state, power management therefore should consider the effect of periodic interrupt services. In this paper, we deal with this issue in two different cases. In case the periodic interrupt cannot be disabled, we formulate the power consumption of idle state, and propose static and dynamic approaches for the optimal frequency selection to save idle power. On the other hand, in case the periodic interrupt can be disabled, we propose the configurable clock tick to disable the interrupt service until the next task is released so that the processor can stay in the low power mode for longer time. The proposed approaches are implemented in a real-time OS; and its efficiency has been validated by theoretical calculations and actually measurements on an embedded processor.