With the host of 32-bit microcontroller chips available now in the market, and also due to the trend of Internet of Things (IoT) applications, where complex communication protocols such as IPV6 are getting integrated into the system, embedded system designers are now looking for very lightweight real-time operating system for microcontroller-based embedded systems. Due to the increased use of ARM Cortex M processor core in microcontrollers, there is some amount of architectural commonality between microcontroller chips from different vendors. Similar, if not identical architecture of microcontrollers help embedded system designers to easily port RTOS.
Now you have in the market both free as well as proprietary paid real-time operating systems from multiple vendors.
One of the popular free RTOS for microcontrollers is "FreeRTOS" from Real Time Engineers Ltd. FreeRTOS was downloaded >113000 times in 2014. You name the leading microcontroller vendor such as ARM, STMicroelectronics, NXP, Xilinx, Altera, Atmel; they all are partners of freeRTOS.
To give you the info on what all the things available from FreeRTOS, they include: Low cost pre-ported libraries for InterNiche TCP/IP, 3rd party driver packages for FreeRTOS BSPs, Super lean FAT FS, Thread aware UDP stack, Tracealyzer for FreeRTOS, CyaSSL SSL / TLS: Networking security protocols, and FreeRTOS+TCP a open source and thread safe TCP/IP stack for FreeRTOS.
If you'd like to know what is the memory you need to store source code in your embedded system, it is in the range of 20 to 30 K (with all the stacks loaded for whatever this OS supports).
The latest version FreeRTOS V8.2.1 is released supporting T I MSP432 (ARM Cortex-M4F), STMicroelectronics STM32F7 (ARM Cortex-M7), Atmel SAMV7 (ARM Cortex-M7), and Microblaze demos, plus a new feature - TLS Pointers. To know more on this visit:
There is extensive support available online from freeRTOS to develop Internet of Things applications faster.
Some of the power management features in freeRTOS for low-power embedded system applications mainly for wearable IOT includes:
The FreeRTOS tickless idle mode stops the periodic tick interrupt during idle periods (periods when there are no application tasks that are able to execute), then makes a correcting adjustment to the RTOS tick count value when the tick interrupt is restarted.
Stopping the tick interrupt allows the microcontroller 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.
You can find good number of demo applications and low-power at the free RTOS website, some of the examples include Low Power RTOS Demo - ST STM32L, and Low Power RTOS Demo - Atmel SAM4L. Both STM32L and SAM4L are some of the best low-power microcontroller chips in the market.
Free RTOS is already popular, to learn more on freeRTOS visit: