Operating system directed power reduction on EFM32

Abstract

Power consumption has become a major concern of embedded systems.Currently FreeRTOS wastes a power waking up regularly to keep track of time.In this work FreeRTOS is modified to sleep when there is no work for the CPU to be done.Timekeeping while sleeping is done by a low frequency oscillator, consuming very little power.Drivers for peripherals have been developed, in order to optimise power consumption even more. Battery life time has been increased from 56 hours to 1867 hours for a simple self made benchmark.The goal is to get the changes into the official FreeRTOS distribution, but it has not been accepted yet.However, a customer of Energy Micro has started to develop an application based on this design.