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For most of the functionalities that we are going to use in this tutorial, you can check the. We will start our setup function by opening a serial connection, in order to be able to get the output of our testing program.
ESP32 Arduino: Creating a FreeRTOS task
This will be our regular Arduino function. Then, we will create the tasks, with a call to the xTaskCreate function. The arguments to this function are the following :. TaskCode : In this argument, we need to pass a pointer to the function that will implement the task. We will create two functions, TaskOne and TaskTwowhich we will define latter and will be passed in this argument.
TaskName : The name of the task, in a string. StackDepth : The size of the stack of the task, specified as the number bytes. There is no simple way of determining the size of the task , although some calculations can be made. In this simple example, we will pass a value that is big enough. Parameter : Pointer to a parameter that the task function can receive. In this case, for simplicity of the code, we will not use it, so we pass NULL in the argument.
Priority: Priority of the task. We will create both tasks with the same priority. TaskHandle: Returns an handle that can be used for latter reference of the task on calls to functions for example, to delete a task or change its priority . Also, for this simple example, we are not going to use it, so it will be NULL.
This function returns pdPASS on success or an error code that can be seen here . For now, we will assume that the tasks will be created without any problem, so we are not going to do any error checking. Naturally, for a real case scenario application, we would need to do that to confirm the tasks were created. So, check bellow the full setup function, already with the calls create the two different tasks.
Now, we only need to specify the functions for the tasks.Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
Already on GitHub? Sign in to your account. The text was updated successfully, but these errors were encountered:. I want to have a different thread where a little rest api is running and responds to get requests. This intirely separated from the main loop. API is exactly the same I'm not quite sure what the issue is here? I'm on freertos. Is there a sufficient API for doing that? As this is a thread "for reference" I wanted to ask a few questions, and add the answers to this thread for later documentation.
I do know that xTaskCreatePinnedToCore can be used to pin the task to a specific core, but if I am simple going to schedule numerous tasks, how does xTaskCreate determine which core the task will run on? I have read the documentation here, and it does not seem to specify how core selection is done in this xTaskCreate case? Is this correct? I could then potentially have a loop that is using a timer or other input event to create a set of tasks that run once, and then terminate. Is there a way to determine how "busy" either core is, to measure and determine where I want to run tasks?
Thank you VERY much for this reference Per what I have read, it appears that the following are the answers to my questions:. I'm thinking of how I can write some code to verify this is the case. I did find a few more references to ways to gather task and CPU utilization information. I'll again have to write some test code and see what I get, but these seemed to have touched on the areas that I'm interested in. I have found it fairly straightforward to use task control tools as you mentioned to manage the tasks as opposed to playing with scheduling at run time.
As for gathering task information, only some are available based on the FreeRTOS configuration file in IDF so be prepared for the usage pf some to result in errors. I use those for checking the task heap and whether tasks are blocked primarily. Skip to content. New issue.Post by stefanoxjx » Thu Mar 15, pm. Post by kolban » Thu Mar 15, pm. Post by WiFive » Fri Mar 16, am.
Post by jeanleflambeur » Fri Mar 16, am. Post by stefanoxjx » Fri Mar 16, am. Post by stefanoxjx » Sat Mar 17, am. Post by kolban » Sat Mar 17, pm.ESP-IDF#6: Creating a FreeRTOS task on ESP32 - ESP-IDF - FreeRTOS
Post by cpersoz » Fri Feb 07, pm. Post by markkuk » Sat Feb 08, am. Users browsing this forum: Baidu [Spider]Google [Bot] and 44 guests. Espressif Systems is a fabless semiconductor company providing cutting-edge low power WiFi SoCs and wireless solutions for wireless communications and Internet of Things applications.
Skip to content. Post by stefanoxjx » Thu Mar 15, pm Hi, I'm trying to write a class, but I've a compilation error. Anyone can tell me why? This is the interested code Code: Select all include "led. Post by kolban » Thu Mar 15, pm In your code, the function blinkLedTask is not a static function. Putting this another way, the function can't be called directly outside of the context in which the "class" in which it exists is passed. Code: Select all X Salary::increase. Post by jeanleflambeur » Fri Mar 16, am Do this: led.
Post by stefanoxjx » Fri Mar 16, am Hi, thanks at all for answers. I'm was wrong because I was putting "static" in header and cpp files. With "static" only to header file I can compile, but I've a "panic" messages. Exception was unhandled. Post by WiFive » Fri Mar 16, am Probably you didn't call vtaskdelete at the end of your task. Post by kolban » Sat Mar 17, pm In your post, we see that the exception was caught at led. However, I couldn't tell what source statement line 88 was at.
It might be beneficial to post a copy of the source to pastebin to allow us to see the offending statement. Jump to.
ESP32: Running code on a specific core
All times are UTC Top. About Us Espressif Systems is a fabless semiconductor company providing cutting-edge low power WiFi SoCs and wireless solutions for wireless communications and Internet of Things applications. Espressif ESP Available now!Post by marko. Post by Ritesh » Sat Jun 29, am. Post by Ritesh » Sat Jun 29, pm. Users browsing this forum: Baidu [Spider] and 44 guests.
Espressif Systems is a fabless semiconductor company providing cutting-edge low power WiFi SoCs and wireless solutions for wireless communications and Internet of Things applications. Skip to content. Basically, I am using the xTaskCreate function in order to organize the function calling like tasks. Let's say, so far so good, the code is running but I am not sure if the approach is right.
At the moment I am not sure for how long can I go this way and how much the code can expand. Re: xTaskCreate - the propper usage Post by marko. My application is not so time-sensitive, I can tolerate a slight drift of some amount of mS. The thing I am concerned about the number of tasks so here is a list of my tasks: 1.
DHT22 sensor on one-wire 6. Two DPS Pressure sensors 7. PMS particle sensor MQTT task OTA task These are just major tasks, but there are a couple of tasks that should be working around the scheduler, main algorithm, etc. Most of these tasks are called once in a couple of seconds so I believe that there is a time frame where the CPU is offloaded, but still, I don't have metrics to determine how much did I loaded the CPU.
Regards Marko. Jump to. Who is online Users browsing this forum: Baidu [Spider] and 44 guests. All times are UTC Top.It is done by creating tasks. Let's look at the hello worldthat looks a little different from the ones that you might have seen. This hello world prints the string on UART eventually on the computer terminal. Then look at the hello world example and modify it blink an LED while still continuously printing the 'hello world' string.
The components directory holds all the 'C' code for the ESP It contains all the 'components' that make up the ESP If we expand the components the tree looks like so:. As you notice each of the component folders one or more.
To include a component we need to include the corresponding. Our hello world example needs 4 of these components. This is the first function that gets called automatically. The function that is called from the task created above is a simple function as shown below. It simply prints the string to the UART. What if I wanted to continuously send a string, say every milliseconds while the LED is still blinking? It is easy to accomplish that using the RTOS.
Arduino ESP32 FreeRTOS 1: How to create a task
So the code below, create two tasks. For now, simply assume that these are two infinite while loops. Whenever one enters delay state vTaskDelay functionthe other runs and vice-versa. Since we are slow and ESP32 is fast, it switches between the tasks numerous times and we see both the tasks happening simultaneously.
Your browser does not support the video tag. A little food for thought, can you figure out many times the string is printed during a single LED blink? Can I create more tasks? Can I use this to multi-task when handling WiFi data on one hand and handling sensor data from other side.
Log in.The objective of this post is to explain how to run code on a specific core of the ESP32, using the Arduino environment support. One of the many interesting characteristics of the ESP32 is that it has two Tensilica LX6 cores , which we can take advantage of to execute our code with greater performance and more versatility.
On this previous post, we already covered a way of knowing in which core a task is executing, by using the xPortGetCoreID function. We also saw that when we create a task with the xTaskCreate function, it may be assigned to any of the two ESP32 cores .
So, to pin the execution of a task to a specific ESP32 core, we need to execute the xTaskCreatePinnedToCore function, which receives as one of its arguments the core ID where to execute. We will analise it in more detail in the coding sections. For now, we will give a very simple example on how to use the previously mentioned function to launch a very basic task on the two different cores of the ESP Since we will start playing with ESP32 multi core code execution, we need to have a way to confirm that the APIs are correctly working and we are getting the desired results.
So, we will first go back to two previous posts to gather some evidences and designing a use case suitable to confirm that everything is fine.
Other important aspect is that, on FreeRTOS, tasks have an assigned priority which the scheduler uses to decide which task will run . High priority tasks ready to run will have preference over lower priority tasks , which means that as long as a higher priority task can run, a lower priority task will not have the CPU. So, if we take this to an extreme situation where the high priority task never leaves the CPU, a starvation situation will occur, meaning that the lower priority task will never gain access to the CPU and progress on the execution of its code .
But if there are two cores available, both of the tasks should be able to run, even if the higher priority task never blocks its execution, as long as they are assigned to the different cores. For implementation purposes, we need to take in consideration that FreeRTOS priorities are assigned from 0 to N, where lower numbers correspond to lower priorities . So, the lowest priority is 0. With this in mind, the application we will design will allow us to launch a FreeRTOS task on core 0 or 1, in the setup function.
This task will have priority 0, which is lower than both the setup and main loop functions. Then, on the Arduino main loop function, we will do an infinite loop, without any type of delay or yielding mechanism, in order for it to maintain the CPU. Remember that the Arduino main loop runs on core 1. Finally, we will analise if the task will starve when executing on ESP32 core 1 and will be able to run when executing on core 0, which is the expected behavior. First of all, we will declare a global variable that will contain the number of the core where the FreeRTOS task we will launch will be pinned.
This ensures that we can easily change it when testing the code.
Note that we will run the code twice, assigning both the values 0 and 1 to this variable. We could have created a more sophisticated approach that receives as a serial input the core where the task should be pinned, but I wanted to keep the code as simple as possible to focus on the multi core functionality. Then, we will go for the setup function.
In the beginning, we open a serial connection with a baud rate ofin order to send some informative messages to the Arduino IDE serial monitor. After that we will print the number of the core we are testing, which is stored on the previously declared global variable. This function takes exactly the same arguments of the xTaskCreate and an additional argument at the end to specify the core where the task should run. If you need help with the process of creating a task and the inputs needed, please check this previous post that contains a detailed explanation on how to use the xTaskCreate function.
We will implement the task in a function called coreTask. We will check the code for it latter. Also, as stated in the previous section, we should attribute priority 0 to the task, so it is lower than both the setup and the main loop. After this call, we will just print another informative message to the serial port indicating the task is created. Now we will design the main loop, which will be very simple. We start by printing a message to the serial port indicating we are starting the main loop, so we now in which point of execution of the code we are.
After that we will do an infinite while loop, without any code inside it. This way, we now the scheduler will maintain the CPU execution assigned to it.
The task function will also be very simple. Naturally, this must correspond to the core specified in the global variable. Then we do an infinite loop where we print this message, with a small delay in each iteration.As Binary Semaphore As Counting Semaphore As Event Group ISR to Task Streams All rights reserved.
Click here to view a static menu. Each task requires RAM that is used to hold the task state, and used by the task as its stack. If a task is created using xTaskCreateStatic then the RAM is provided by the application writer, so can be statically allocated at compile time.
See the Static Vs Dynamic allocation page for more information. Parameters: pvTaskCode. Pointer to the task entry function just the name of the function that implements the task, see the example below. Tasks are normally implemented as an infinite loopand must never attempt to return or exit from their implementing function.
Tasks can however delete themselves. A descriptive name for the task. This is mainly used to facilitate debugging, but can also be used to obtain a task handle.
The number of words not bytes! For example, if the stack is bits wide and usStackDepth isthen bytes will be allocated for use as the task's stack. As another example, if the stack is bits wide and usStackDepth is then bytes will be allocated for use as the task's stack.
See the FAQ How big should the stack be? A value that will passed into the created task as the task's parameter.