.. _design_rtos: RTOS ==== .. _design_rtos_overview: Overview -------- In Nuclei SDK, we have support three most-used RTOSes in the world, **FreeRTOS**, **UCOSII** and **RT-Thread** from China. If you want to use RTOS in your application, you can choose one of the supported RTOSes. .. note:: When you want to develop RTOS application in Nuclei SDK, please don't reconfigure ``SysTimer`` and ``SysTimer Software Interrupt``, since it is already used by RTOS portable code. .. _design_rtos_freertos: FreeRTOS -------- `FreeRTOS`_ is a market-leading real-time operating system (RTOS) for microcontrollers and small microprocessors. In our FreeRTOS portable code, we are using ``SysTimer Interrupt`` as RTOS SysTick Interrupt, and using ``SysTimer Software Interrupt`` to do task switch. These two interrupts are kept as lowest level, and ``SysTimer Interrupt`` is initialized as non-vector interrupt, and ``SysTimer Software Interrupt`` is initialized as vector interrupt and interrupt handler implemented using asm code. In our FreeRTOS porting, we also allow FreeRTOS configuration variable ``configMAX_SYSCALL_INTERRUPT_PRIORITY`` which can be find in https://www.freertos.org/a00110.html. The ``configMAX_SYSCALL_INTERRUPT_PRIORITY`` should be set to be a absolute interrupt level range from 1 to (2^lvlbits-1) while ``lvlbits = min(nlbits, CLICINTCTLBITS)``. If you set configMAX_SYSCALL_INTERRUPT_PRIORITY to value above the accepted value range, it will use the max value. If you want to learn about how to use FreeRTOS APIs, you need to go to its website to learn the FreeRTOS documentation in its website. In Nuclei SDK, if you want to use **FreeRTOS** in your application, you need to add ``RTOS = FreeRTOS`` in your application Makefile. And in your application code, you need to do the following things: * Add FreeRTOS configuration file -> ``FreeRTOSConfig.h`` * Include FreeRTOS header files .. note:: * You can check the ``application\freertos\demo`` for reference * Current version of FreeRTOS used in Nuclei SDK is ``V10.3.1`` * If you want to change the OS ticks per seconds, you can change the ``configTICK_RATE_HZ`` defined in ``FreeRTOSConfig.h`` More information about FreeRTOS get started, please click https://www.freertos.org/FreeRTOS-quick-start-guide.html .. _design_rtos_ucosii: UCOSII ------ `UCOSII`_ a priority-based preemptive real-time kernel for microprocessors, written mostly in the programming language C. It is intended for use in embedded systems. In our UCOSII portable code, we are using ``SysTimer Interrupt`` as RTOS SysTick Interrupt, and using ``SysTimer Software Interrupt`` to do task switch. If you want to learn about ``UCOSII``, please click https://www.micrium.com/books/ucosii/ We are using the opensource version of UC-OS2 source code from https://github.com/SiliconLabs/uC-OS2, with optimized code for Nuclei RISC-V processors. In Nuclei SDK, if you want to use **UCOSII** in your application, you need to add ``RTOS = UCOSII`` in your application Makefile. And in your application code, you need to do the following things: * Add UCOSII application configuration header file -> ``app_cfg.h`` and ``os_cfg.h`` * Add application hook source file -> ``app_hooks.c`` * Include UCOSII header files .. note:: * You can check the ``application\ucosii\demo`` for reference * The UCOS-II application configuration template files can also be found in https://github.com/SiliconLabs/uC-OS2/tree/master/Cfg/Template * Current version of UCOSII used in Nuclei SDK is ``V2.93.00`` * If you want to change the OS ticks per seconds, you can change the ``OS_TICKS_PER_SEC`` defined in ``os_cfg.h`` .. warning:: * For Nuclei SDK release > v0.2.2, the UCOSII source code is replaced using the version from https://github.com/SiliconLabs/uC-OS2/, and application development for UCOSII is also changed, the ``app_cfg.h``, ``os_cfg.h`` and ``app_hooks.c`` files are required in application source code. .. _design_rtos_rtthread: RT-Thread --------- `RT-Thread`_ RT-Thread was born in 2006, it is an open source, neutral, and community-based real-time operating system (RTOS). RT-Thread is mainly written in C language, easy to understand and easy to port(can be quickly port to a wide range of mainstream MCUs and module chips). It applies object-oriented programming methods to real-time system design, making the code elegant, structured, modular, and very tailorable. In our support for RT-Thread, we get the source code of RT-Thread from a project called `RT-Thread Nano`_, which only provide kernel code of RT-Thread, which is easy to be intergated with Nuclei SDK. In our RT-Thread portable code, we are using ``SysTimer Interrupt`` as RTOS SysTick Interrupt, and using ``SysTimer Software Interrupt`` to do task switch. And also the ``rt_hw_board_init`` function is implemented in our portable code. If you want to learn about ``RT-Thread``, please click: * For Chinese version, click https://www.rt-thread.org/document/site/ * For English version, click https://github.com/RT-Thread/rt-thread#documentation In Nuclei SDK, if you want to use **RT-Thread** in your application, you need to add ``RTOS = RTThread`` in your application Makefile. And in your application code, you need to do the following things: * Add RT-Thread application configuration header file -> ``rtconfig.h`` * Include RT-Thread header files * If you want to enable RT-Thread MSH feature, just add ``RTTHREAD_MSH := 1`` in your application Makefile. .. note:: * In RT-Thread, the ``main`` function is created as a RT-Thread thread, so you don't need to do any OS initialization work, it is done before ``main`` * We also provide good support directly through RT-Thread official repo, you can check Nuclei processor support for RT-Thread in `RT-Thread BSP For Nuclei`_. .. _FreeRTOS: https://www.freertos.org/ .. _UCOSII: https://www.micrium.com/ .. _RT_Thread: https://www.rt-thread.org/ .. _RT-Thread Nano: https://github.com/RT-Thread/rtthread-nano .. _RT-Thread BSP For Nuclei: https://github.com/RT-Thread/rt-thread/tree/master/bsp/nuclei/