When using a smaller ARM micro, without the benefit of large amounts of SDRAM, often some kind of specialised real-time operating system must be used to provide the kind of functionality that modern software required (Threads, Mutexes, TCP/IP, Wifi etc...). There are numerous options available, ranging from freely available open-source solutions, to well supported vendor-supplied solutions. When evaluating a new system for a Cortex-M3 core on a recent design, we investigated 3 options:
These represent a reasonable selection, each providing a similar array of functionality. The final decision depends greatly on the tools that the developer is already familiary with. RL-ARM works best when already using the Realview/Keil tools suite and PowerPac for the IAR Workbench. FreeRTOS comes with project files for a variety of different environments, include Keil, Rowley, IAR and GCC. In the end the decision depends on the project requirements, budget, and tools availability, and for our project we choose the IAR PowerPac, as the tools were already being used by the customer.
