WITTENSTEIN: ultra-low power mode available for SAFERTOS
A new Ultra-Low Power Mode is available for SAFERTOS, a safety critical real time operating system from WITTENSTEIN high integrity systems. The new Ultra-Low Power Mode is provided as a highly integrated port layer that makes most efficient use of the processors’ low power features.
SAFERTOS is a pre-certified, pre-emptive, safety critical Real-Time Operating System (RTOS) based on the functional model of the FreeRTOS kernel. SAFERTOS delivers determinism and robustness to embedded systems, whilst using minimum resources. SAFERTOS supports mixed safety criticality designs through use of the processors’ Memory Management Unit/ Memory Protection unit, multicore devices and is available pre-certified to IEC 61508 SIL 3 and ISO 26262 ASIL D.
Where supported by the processor, SAFERTOS can be purchased supporting a tickless Ultra-Low Power Mode. Here power is saved by completely stopping the RTOS tick interrupt during idle periods and placing the system in a power saving mode. Stopping the tick interrupt allows the processor to remain in a deep power saving mode longer until either an interrupt occurs, or it is time for the RTOS to re-activate a Task.
This is a significant advantage in power saving over the common method of reducing the power consumed by the processor by using the idle Task hook to place the processor into a low power state. Stopping the tick interrupt entirely allows SAFERTOS to remain in a deep power saving state until either an interrupt occurs, or it is time for the RTOS kernel to transition a task into the Ready state. SAFERTOS can then make a correcting adjustment to the RTOS tick count value when the tick interrupt is restarted.