Sleep Mode Extends Battery Life Under Linux

A sleep mode/power management package for Linux/Strong ARM SA1110 platforms promises to extend the operating time of battery-powered systems to several weeks. As a reference, Graphics Client Plus 4" x 6" single board computer system consumes on average 2W (2,000 mW) of power in full operation, with a little less than half a Watt (495 mW) consumed by the StrongARM SA-1110 microprocessor. In contrast, the Graphics Client Plus System uses less than 10 mW in sleep mode. In contrast to traditional on/off and idle modes, when this sleep mode is initiated sleep, all peripherals are powered off. Only the SDRAMs and the StrongARM I/Os and real-time clock remain active in a minimum power mode. A call to a sleep function by the application or by an inactivity timeout initiates the state, which notifies all device drivers. In sleep mode, the kernel can reactivate in a timely fashion without reloading and uncompressing the kernel from non-volatile memory. For more information, contact APPLIED DATA SYSTEMS INC., Columbia, MD. (800) 541-2003.