Turning off the tick in the RTOS cuts MCU power consumption

September 01, 2014 // By Graham Prophet
Segger has added tickless low power support to its embOS real time operating system. The tickless low power feature reduces the power consumption for battery powered devices; it stops the periodic system tick interrupt during idle periods. Instead of having a timer interrupt for each system tick the timer is reprogrammed to be able to spend as much time as possible in low power mode.

One of the most common ways to reduce power consumption is to keep the processor in sleep (idle) mode for as long as possible. Typically an RTOS will wake the processor on a regular system tick - even if there is nothing to do. The embOS tickless low power support reduces power consumption by creating a variable length system tick which allows the processor to continue sleeping when there are no application tasks to execute.

Stopping the tick interrupt allows the microcontroller to remain in a deep power saving state until either an interrupt occurs, or the RTOS kernel has to transit a task into the ready state. This can make a huge difference in battery life.

Tickless support can be added to any embOS project and is available with the latest version of Segger's embOS real time operating system. Segger provides application notes for tickless support for different CPUs.

Segger; http://segger.com/tickless-support.html

embOS is a high-performance real-time OS that has been optimised for minimum memory consumption in both RAM and ROM, as well as high speed and versatility. It supports fully nested interrupts for zero interrupt latency. embOS is a priority-controlled multi-tasking system, designed as an embedded operating system for real-time applications for all popular CPUs. It provides a migration path with identical APIs across all platforms. embOS is available as full source code and comes with a simple licensing model without royalties. Full product specifications and a trial version are available at: http://segger.com/embos.html