Embedded Systems Low-power Research

As the demand for diversified intelligent control systems, smart toys, industrial control, handheld devices ,the application of the embedded system constantly growing and popular. Especially in recent years, with the popularity of cell phone, PDA, MP3 and other popular handheld system, system power consumption became the bottleneck and one of the key technologies of the product design.To meet the performance needs of users on the premise,the goal of low-power embedded system design is reduce system power consumption as much as possible, and extend equipment standby time.With the increasingly prominent contradictions between the embedded devices small size, high performance and limited battery power contradiction, low-power embedded system design become an effective means to resolve this contradiction.Power consumption is a system problem, want to effectively reduce the overall power consumption, must taking into account the needs of hardware and software design, as well as their co-ordination.Hardware is the substances platform of operating system, including processors and peripherals. Low-power processor most adopt the system-level design, the technologies include: reconfigurable dynamic cache and cache closed, gated clock technology, dynamic voltage scaling DVS technology, multi-core technology. Peripheral equipment low power design include: design a reasonable external circuit modules, closing idle equipment components; meet basic performance requirements premise, choose low-power devices,and so on. Software low-power design including compiler optimization, power management, and application software compiles and so on. For embedded systems, the uneven work load as well as dynamic change, in recent years, there appears a dynamic power management DPM technology, which provides an operating system-level power management capabilities, consider the implementation of power management strategy when procedures in the running.Based on the linux operating system research, through the revision of linux scheduling algorithm, the scheduling algorithm in accordance with the process of run_queue to achieve variable voltage techniques, and change the processor frequency and voltage to lower power consumption. But in a real-time process, where it exists, in order to meet the response of the processing, power consumption control will be closed. Llinux operating system so that not only the design of a low-power purposes, but also affecting the system's responsiveness.Finally, use the simulation software skyeye to simulate the lubbock development board based on pxa250 processor, validated the improve of linux operating system for low-power design.