uC/OS-II, RTOS - implementation on  ATMega128 platform

Program controls work of AVR uC using a real time system  uC/OS-II (v 2.6) from Micrium. It secures context task switching and offers a lot more mechanismus  which assist designing of real time systems.                                                                                                                  more...

Real Time Operating System uC/OS-II – the AT91R4008 port (ARM7 core)

From the beginnings of the uC/OS-II RTOS existence has the implementation for ARM based CPUs. This ports are usually made using Micrium application note and thus they are ignoring some microcontroller specific needs. The main problem with existing implementation is that they are using 32 bits instructions in native so called ARM mode which is a quite problematic on microcontrollers with 16 bit data bus. The effect such approach is the delay of fetching instructions from memory (apart of memory wait cycles there are needed two full fetch cycles for each instruction). Because of this bottleneck all profits from ARM RISC (32 bit instruction executed in one CPU clock cycle) architecture are lost.                                                   more...