Is it possible to use notifiers in the CMSIS2 version of FreeRTOS?

[JGree.11]

Hello,

Is it possible to use notifiers in the CMSIS2 version of FreeRTOS which ships with CubeMX / CubeIDE? FreeRTOS native functions are often vTask...() but the CMSIS versions are osThread...(). When I try to call notifier functions from FreeRTOS directly bypassing CMSIS the debugger falls over. Running on Nucleo F303RE. For now I will use a binary semaphore instead, the functions for which are in CMSIS.

Cheers

James

[alister]

Certainly you may call FreeRTOS directly, and then your code size will be smaller and it'll execute faster too.

Cube uses CMSIS_RTOS so it can (a) easily ditch FreeRTOS if ST find cause and (b) easily integrate third-party middleware, e.g. lwIP.

Once you've shipped you product and you're only adding odd features to make customers happy or to better position the product in the market, and you're not changing/generating your Cube configuration, you'd only update the Cube and/or FW package if you really really have to, e.g. for a security-fix, because (a) it's a lot of effort to find and fix the new problems it'd cause and (b) it won't increase your sales.

So the only risk to using FreeRTOS directly is ST ditching FreeRTOS before your development's ready, and then you'd have to change the parts of your app using FreeRTOS directly to use the next RTOS.

The CMSIS_RTOS wrapper is in "Middlewares\Third_Party\FreeRTOS\Source\CMSIS_RTOS\cmsis_os.c". Mostly it's wraps FreeRTOS directly. But CMSIS_RTOS numbers task priorities differently, and Cube wants to create at least one task and start the scheduler in main.c, and as you design and implement your app you'd want to plan your task priorities in one number space.

So in my apps I create tasks with CMSIS_RTOS and do mostly everything else with FreeRTOS direct.

> When I try to call notifier functions from FreeRTOS directly <snip> the debugger falls over

This is all documented many places on the web. https://www.freertos.org/RTOS-task-notifications.html boasts notifications are 45% faster than semaphores!

 TaskHandle_t myThread;
 
 <snip>
 
 // creating the thread
 osThreadDef(myThreadName, MyThread, MY_THREAD_PRIORITY, 0, MY_THREAD_STACK_SIZE);
 myThread = osThreadCreate(osThread(myThreadName), myArgs);
 
 <snip>
 
 // notifying from an interrupt
 vTaskNotifyGiveFromISR(myThread, &taskWoken); // &taskWoken = null if don't care
 
 <snip>
 
 // notifying from a task
 xTaskNotifyGive(myThread);

[MMeie.2]

I prefer to create tasks and scheduler start myself using native FreeRTOS functions.

For this the auto generated CubeMX initialization must be deacivated, eg. by define following macros in section "USER CODE ... PM" of main.c :

/* USER CODE BEGIN PM */

#undef osThreadDef

#define osThreadDef(...)

#define osThreadCreate(...) NULL

#define osKernelStart()

/* USER CODE END PM */

[alister]

>For this the auto generated CubeMX initialization must be deacivated, eg. by define following macros in section "USER CODE ... PM" of main.c :

I like that idea!

[JGree.11]

Many thanks for your answers.

James

[MMeie.2]

Even nicer would be if STM would add a "native" FreeRTOS option in the CubeMX Cconfigurator ;)