Power management on embedded devices boils down to an amazingly simple principle "turn-off anything you don't use". Though this sounds fairly simple, the actual implementation can be quite complex. The Nucleus real-time operating system attempts to minimize the complexity by taking care of as many of the nitty-gritty details as possible, allowing the software developer to make high-level decisions, but also giving the developer the option of full control if desired. This paper covers a few of the power management techniques that define device static power consumption.
Mentor Graphics, RTOS, Power Management