About uC-OS2

uC-OS2 (a.k.a. uC/OS-II or MicroC/OS-II) is a full-featured embedded operating system originally developed by Micrium. In addition to the two highly popular kernels, uC-OS2 features support for TCP/IP, USB-Device, USB-Host, and Modbus, as well as a robust File System.

NOTE: Micrium and all its products, inlcuding uC-OS2, were acquired by Silicon Labs in 2016. Silicon Labs later decided to release all Micrium products under the permissive open source Apache License, Version 2.0. Around 2020, the custody of the uC-OS RTOS and other Mircium products was taken over by Weston Embedded Solutions, which is a company founded by a team of former Micrium employees.

uC-OS2 Source Code

The uC-OS2 code ( V2.93.01) has been forked from the Weston Embedded GitHub repository:

https://github.com/weston-embedded/uC-OS2

NOTE: The uC-OS2 from GitHub has been modified by Quantum Leaps to comply with CMSIS and to adapt the GNU-ARM ports for the new GCC ARM toolset.

Modifications by Quantum Leaps

The uC-OS2 from Weston Embedded has been modified by Quantum Leaps in the following ways:

ARM Cortex-M Ports

The original uC-OS2 ports directory has been pruned and only the ports to ARM Cortex-M relevant to the Quantum Leaps examples have been retained.

CMSIS Support

The uC-OS2 ports to ARM-Cortex-M have been modified by Quantum Leaps to remove the dependencies on the Micrium's uC-CPU and uC-LIB components, and instead to comply with the Cortex Microcontroller Software Interface Standard (CMSIS). Specifically, the names of the standard exception handlers OS_CPU_PendSVHandler and OS_CPU_SysTickHanlder used by the original uC-OS2 ports have been changed to be CMSIS-compliant names: PendSV_Handler and SysTick_Hanlder, respectively.

FPU Support

Additionally, the Cortex-M4F ports have been modified to include the FPU configuration that is expected by the uC-OS2 port to Cortex-M4F, which was different from the FPU configuration performed by the CMSIS-compliant startup code. Specifically, the explicit FPU configuration has been OSInitHookEnd() function in the file os_cpu_c.c.

GCC-ARM 14.3 Support

Additionally, the ARM Cortex-M ports for the GNU toolchain have been modified for the new binutils 2.44 (present in the GCC-ARM 14.3.1), which require differnt syntax in assembly. Specifically, assembly functions must be designated as .type <function-name>, %function. Without such designation the GCC linker reports the following error:

dangerous relocation: unsupported relocation