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FreeRTOS Tutorial 2.0 || TASK Operations || STM32 || CUBEIDE
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Nov 19, 2019
Purchase the Products shown in this video from :: https://controllerstech.store ________________________________________________________________________________________ FreeRTOS PART1 :::: https://youtu.be/muOL9SH0p9g FreeRTOS PART3 :::: https://youtu.be/SsBgNFEpfFE FreeRTOS STM32 Playlist :::: https://www.youtube.com/playlist?list=PLfIJKC1ud8gj1t2y36sabPT4YcKzmN_5D STM32 Playlist :::: https://www.youtube.com/playlist?list=PLfIJKC1ud8gga7xeUUJ-bRUbeChfTOOBd DOWNLOAD THIS PROJECT FROM :::: http://controllerstech.com/free-rtos-tutorial-2-0-with-stm32/ ________________________________________________________________________________________ ******* SUPPORT US BY DONATING****** https://paypal.me/controllertech *******Join the Membership******* https://www.youtube.com/channel/UCkdqtSMnhYuMsJkyHOxiPZQ/join
View Video Transcript
0:07
hello everyone welcome to controllers
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tech as I promised to continue the free
0:14
rtos tutorials today I brought to you
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another video on our TOS in this video
0:22
we will see the various operations that
0:25
we can perform on the tasks let's start
0:28
by creating the project in cube ID first
0:31
I am using stm32f4 for 6 our controller
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give some name to it and click finish
1:01
now first of all I am going to select
1:04
the external clock
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[Music]
1:13
I am using CM sis version one as it it's
1:17
supported majority of the stm32 devices
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leave everything as it is
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just enable the V task delay until it's
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an important parameter and I will
1:29
explain you how it works
1:36
[Music]
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in the SIS time based source select any
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source other than cystic I am using
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timer one next set up the clock and
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click Save to generate the project
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[Music]
2:19
I am including stdio dot H file because
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I am going to use the printf to debug we
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have to define a new write function I
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already made a video about printf
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debugging check that on the top right
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corner first of all let's see if the
2:37
things are working properly before
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everything starts
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[Music]
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[Music]
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a default task is already defined by
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default this is to check if the task
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runs or not giving a delay of one second
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for this task let's build the code
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[Music]
3:22
in the debug configuration enable the
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serial wire viewer in the core clock
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type the frequency of the HC LK
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[Music]
3:41
[Music]
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now go to windows show view SWV and
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select I TM data console in the setting
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enable the comparator 0 and check the
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stimulus port 0 press the red button to
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start recording now you can see the
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printf string being printed on the
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console this means that the default task
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is running well every one second
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[Music]
4:29
[Music]
4:33
now let's create another task to do so
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first we need to define the task handler
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next define the entry function for the
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task
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[Music]
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now inside the main function first to
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find the thread also thread deaf takes
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the following parameters name of the
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task entry function for the task
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priority I am giving it higher priority
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than the default task instance and stack
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size next we need to assign the ID of
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this task to its handler
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now I am writing the entry function for
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this task
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it will print the value of the index
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variable and a delay of two seconds
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let's build it and I will explain you
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how this works
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[Music]
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make sure you press the record button
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[Music]
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okay let's see starting is printed at
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the beginning now the control will be
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transferred to the colonel the colonel
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have two tasks in the ready state
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default task and tasked to the priority
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of task 2 is higher and that's why it
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will run first after running the printf
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statement the task will go in the
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blocked state for two seconds Colonel
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will now run the default task after
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executing the printf statement this task
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will also go into block state for one
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second
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nothing will run for this one second now
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after one second default task will again
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become ready and Colonel will run it
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after printing the task will again go in
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the blocked state for one second nothing
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will run for another second after one
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second both the tasks will be in ready
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state again because it's been two
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seconds since the task 2 was blocked the
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colonel now again have two tasks ready
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to run but it will run the task 2 first
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because of the higher priority and this
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whole process will continue again and
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again
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[Music]
8:20
[Music]
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let's take a look at some other
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functions available for task management
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[Music]
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we are going to take a look at OSD spend
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and OS thread resume functions both of
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them take thread ID as the argument of
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course the thread ID of the thread that
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you want to suspend or resume if index
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becomes for the default tasks should
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suspend
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[Music]
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and if index becomes seven the default
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task will resume
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[Music]
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let's run it now
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make sure you enable the record button
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[Music]
10:27
okay you see it happened now let me
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explain what's happening here
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let's take a look at the task to code
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you see when the index was three it will
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be printed and the index will increment
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to four after this the task will go in
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the blocked state for two seconds when
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the task resumes after two seconds index
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have the value of four and control will
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go inside the if loop the default task
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will be suspended after that this loop
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will not be executed and control will go
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back to the beginning where the value of
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the index will be printed and index will
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be incremented to five the task will be
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blocked for two seconds as there is no
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default task anymore
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this will keep executing every two
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seconds the same thing will happen when
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the index becomes seven the default task
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will resume this time so this was the
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demo for suspend and resume tasks let me
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comment all this next I am going to
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terminate the task to itself
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[Music]
12:05
OS thread terminate also requires the
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thread ID as the argument let's run this
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one now as you can see here the tasked
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who gets terminated and default task
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runs only afterwards we can also
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terminate default tasks
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just give the thread ID of the same once
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the task is terminated
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it can't be resumed this is the
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difference between suspend and terminate
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[Music]
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we can also suspend all or resume all
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threads OS delay until is another
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function I wanted to show you guys it
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blocks the task for some time and
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resumes automatically as you can see the
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description we need to define a variable
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to store the elapsed time
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[Music]
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[Music]
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again I am going to run this under a
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specific condition and once the
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condition is reached the task will be
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blocked for three seconds
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[Music]
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[Music]
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[Music]
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let's run it as you can see the exact
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thing happening here the task you can
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block for three seconds and resumes
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after that
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[Music]
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there are more functions available for
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tasks and I can't cover all of them
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OS thread yield passes the control to
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the next thread that's ready to execute
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again we can use it under some condition
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also there are functions like set
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priority or get priority and so on this
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is it guys
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this video covered many functions for
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task operations I will continue this
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series of our tos and we will cover
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semaphores messages queues etc in the
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coming videos I hope you understood the
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video you can download the code from the
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link in the description have a nice day