Research On A Linux Operating System-Based Energy Saving Of Embedded Microprocessor

Along with the rapid development of computer and communication technology、 the fusion of3C(computer、communication、consumer electronics) and the flourishing technology of triple play (radio and television network、telecommunication network、 the Internet), the embedded system and ARM processors have been widely applied to various fields. And the AT91SAM9G20microprocessor is widely used in the pos terminal、building automation、security cameras and bar code reader and so on, but, these applications are limited by the power in a certain extent. Therefore, how to reduce the microprocessor’s power consumption furtherly has become a key problem. Aiming at this problem, an energy saving scheme based on Linux operating system is presented in this paper, the scheme uses the technology of DPM and changes the basic frequency of microprocessor according to the judgment of the process numbers in process queue and the current cpu utilization rate, at the same time, power consumption control is achieved by a power consumption control module designed and its driving program edited, in the end, the experiments completed by a test program edited demonstrate that the scheme is effective and feasible.In the environment of advovating "energy conservation and emission reduction, low carbon life", It’s necessary for people to consider the problem of reducing the power consumtion from various aspects, consequently, the research on a Linux-based energy saving of microprocessor has a very important significance.The works completed by the author of the paper and the main research contents include:1. Familiar with YL-9G20development board and on that basis further study the cutting and transplantation of Linux operating system、 the entire process from u-boot startup to successfully mounting the root filesystem.2. In-depth study of the AT91SAM9G20microprocessor’s datasheet, and fully understand the work principle of PMC(Power Management Controller).3. According to the proposed scheme of energy saving, power consumption control module is designed and its driving program is edited, familiar with the whole process of the driver development and the use of VI editor and GDB debugger, finally prove that the modified kernel can run normally and power consumption control module is effective by the test program edited.4. The paper finishes the research of the whole energy saving scheme and the design of power consumption control module, they are all feasible, and the experimental results show that the scheme presented in this paper can reduce power consumption considerably for the same condition of the power supply. In the end, it summarizes the difficulties and problems emerging in the course of the study, along with forecasting them, and also does very good summary for the lessons got in the study.