Introduction to RTOS Part 1 - What is a Real-Time Operating System (RTOS)? | Digi-Key Electronics

[@OdotRIH4KRC]

Without the help of Shawn many in the community would be lost. Thanks tons Shawn for all you do.

[@MattKremer]

This is exactly the informational/tutorial series I've been looking for. Even better I found it after it's all done, so I can go straight through it! Thanks!

[@超伝導ゼロス]

Thank you, Dr. Digi-Key. In real time, the narration is displayed in text in the right window of the video. This feature is very useful for me, who has never spoken English.

[@saganasimov4891]

This video series is a goldmine for me, as I want to pursue embedded systems. Thank you very much for this and more videos to come such as this.

[@rickpontificates3406]

As a game programmer for 30 years, when I learned iOS Swift, I had to change my way of thinking about code because Swift doesn’t function like other languages I’ve used. In Swift, there is NO “main loop”. In fact, the Apple device’s OS is the main loop of your app. Everything in your app is accessed by interrupt handling, either a timer interrupt or a human interrupt, like a button push.

[@mieszkogulinski168]

Same in JavaScript, where we also don't have a main loop, programs are functions responding to events like clicking a button (or in case of Node.js like an incoming server request). And the browser is the "operating system" (or Node.js or Bun or whatever else). Okay, a function calling itself recursively using requestAnimationFrame could be something like a "main loop", it's done mostly in games using canvas element...

[@benargee]

​@@mieszkogulinski168 if swift and JS are the same in this regard, they are event driven languages and a loop is still involved, the event loop.

[@sirifail4499]

That’s exactly what I felt the first few times I wrote BREW Apps (Qualcomm’s missed opportunity to become Android).

[@bryanst.martin7134]

I remember 2 decades back when I got a little catalog from them. Only the size of a Readers Digest condensed book, for those that remember those. Now they sit prominently and honorably on the World stage, with a catalog too big to ship, and CS reputation unmatched in my history. Keep it up!

[@tingoyeh4903]

Great video. Other tutorial online are either too hard or too basic, this series of video just match the hole in this field.

[@akulanvn381]

You explained it so perfectly. I was having such hard time understanding RTOS in my embedded systems class this helps incredibly. Thank you for being so informative.

[@ShawnHymel]

That's exactly what inspired me to do this series--I was not a fan of how they were taught in school :)

[@fadieid5638]

How can I take an embedded systems class like yours?

[@gaminggoneviral8063]

Yes!!! Edge Ai and now RTOS!! Love your stuff! please dont stop Sir! These things are actually the next biggest trends. Thanks Sir.

[@veralagarwal2045]

Yeahhh!!.. After learning RTOS in books and Online resources, I got the best from Shawn.

[@abuk95]

Amazing video, now it is clear to me why is RTOS beneficial!

[@jzero4813]

7:40 To be fair, an ESP32 is much cheaper than an Arduino, and has BT/WiFi so I tend to use them even for projects they are wildly overpowered for. Super loops are great for simple projects just due to the law of fewer moving parts. Faster to develop, lower surface area for bugs. Project complexity is the primary deciding factor. Most industrial automation, for example, runs on PLCs, and they are almost universally super loop architectures. Huge scale, loads of I/O, long programs, but still low complexity. Excellent summary, in any case.

[@dani_dupae]

Excellent video! I've been watching these trynna learn more for my microprocessors class.

[@finnyphilipbiju4520]

Thanks for coming up with this tutorial. Was really waiting to explore more on RTOS

[@kenwallace6493]

This intro is as good as any I've seen, especially relevant for deciding if the complexity of RTOS is warranted. In my case, it's not but I feel better sticking with the super loop.

[@jerrywatson1958]

It's the bowtie that keeps me glued. LOL. Thanks for adding a bit of levity to this talk.

[@mattnielsen1468]

This series is a godsend. Excited for the upcoming tutorialsm

[@EarlWallaceNYC]

I've been looking for Shawn. since he left "that other maker site". I like Shawn's style, and his teaching style works for me. He and Digi-key get my vote and more of my business.

[@ShawnHymel]

Thank you for your kind words!

[@TheMateusrex]

Just starting a career in embedded systems, and I'm looking forward to your tutorials. I like your style.

[@ArjanvanVught]

@MichaelKingsfordGray So what would it be? C++ ? Where is FreeRTOS based on? Where is ChibiOS based on? Where is Linux RT based on? All on "C" ?

[@ArjanvanVught]

When exploring embedded systems, then it is also worthwhile looking at the Orange Pi Zero board. This gives you 4 ARM A7 cores with proper DMA EMAC Ethernet.

[@TheMateusrex]

@@ArjanvanVught Thanks!

[@Veeshaljha]

Hi, can you guide me ? I am beginner

[@tonyfremont]

Glad to see you back at it. I watched all your Arduino videos today, and I've seen all your STM32 videos as well. This is awesome content, and I can't wait for the next video in this series.

[@yash1152]

6:59 hardware comparison chart 9:52 "Any board will work as long as they've an associated arduino package"

[@mondherbenromdhane2069]

9:52 I can already hear the booooooo's

[@ko-Daegu]

@@mondherbenromdhane2069 Why thou?? Also do I need engineering background as I got none

[@DeltaPrismo]

Looking to work with that in the future. It's a awesome vídeo. Computer engineer student here ;)

[@mohamedfaroukel-alem7253]

Guy, your explanation is so simple and clear

[@thosewhowish2b693]

Really not sure what I dig more, the presentation or the music. Great job!

[@Kravch96]

Shawn you are a literal embedded god. Thank you so much for your videos

[@enricosaccheggiani3192]

Very good video, I have subscribed , compliments. Many teachers didn't know the difference between thread and task, only this is worth the video

[@UmairAhmadh]

It is really awesome to see this. -A fan

[@alanyorinks805]

Thanks for the excellent series. Explains FreeRTOS in an approachable manner including excellent examples and tips.

[@lt_erwin]

Very good introduction video for RTOS! thank you for sharing this knowledge

[@salmanali2719]

Cannot wait for this series to be completed.

[@PrithaMajumder]

Thank You So Much for This Amazing Video Video Lecture - 1 Completed

[@KangJangkrik]

Finally... Event-driven microcontroller for real! 😁

[@AleemAhmed]

Everything is best explained in this video. Cleared the conecpets. Thanks 👍

[@manjchana]

This is such a great video, very much looking forward to the next one!

[@AmitKumar-yw7ri]

Great i am searching for video like this u know what i found u just one day after u just post ur video, thank u very much i am very eager for next video.

[@jeroenfeher8107]

9:28 Got it. Won't use it then. No guarantee on it's future paths in that case. Your videos are great though for understanding these concepts.

[@amirphilip2234]

Really impressive explanation

[@MultiSchuman]

What is RTOS? Ans: its like any other operating system. Very helpful thankyou.

[@RakshithPrakash]

Top-notch video, please continue this series, thanks

[@tillabakos2248]

A bow tie? A have to take a bow in front of such audacity. And yes, it is a great video indeed.

[@thecoolaravind]

Thanks @Shawn Hymel: Looking forward to the rest of the parts on RTOS !!!

[@clij5202]

I remember, many moons ago, I had a RTOS version on an EPROM cartridge attached to my Atari ST. Many moons ago.

[@JohnWasinger]

My older brother developed on Atari 1040 ST and a 520 ST computers. The operating system on those 68000 based processor systems was called TOS. The OS was burned onto internal ROMS on the main board. There was something called "realtime" for a musical cartridge back on Jun of 1991.

[@clij5202]

@@JohnWasinger Tramiel Operating System ... good ol’ days. Enjoyed that one quite a bit with the M68k family over the years. Was used where I had my first programmer job too for various application. Even developed a TokenRing network and integration into TOS.

[@JohnJonesJMJAtlanta]

Clearly explained, clearly articulated. Thank you.

[@paragbharadia2895]

thanks for creating this course

[@AgainPsychoX]

It's so well done video. I love the series.

[@reshan8239]

Exactly what I needed for my PowerPoint presentation about OS. Thanks man

[@alexandrecvl]

TSpark is the most interesting rtos architecture. The only really original architecture in the market.

[@BavlyS]

Thanks for the great effort you put into making this great introduction.

[@deathvall3y]

very much resourceful, waiting for the next video 💙

[@bharathishrinivasantr4809]

Very well illustrated. Loved the content delivery

[@MisterWillow]

Wow, I just stumbled upon this channel by sheer luck! (Subscribed!)

[@ArjanvanVught]

With a super-loop you would need to implement a state-machine. Hence no locking of tasks. Hence no context switching overhead.

[@nisar-systemarchitect]

Thanks Shawn, the tutorial is very nice. One request would like to make is, music is too loud and your voice is quite low, please make adjustment for better experience. Regards

[@ShawnHymel]

Thanks for the heads up! I'll work on getting the volume down of that intro/outro music.

[@rishiktiwari]

Much awaited Topic!

[@dmytrozota1904]

Thank you for making these tutorials)

[@jerrywatson1958]

I may be late but you earned a new sub today. I am going to invest in this kit. This looks fun, takes me back to my 8080 days as a kid.

[@mrfudd13]

Dude: the ambush music is too loud!

[@ShawnHymel]

Noted, thank you. It will be fixed for ep 3 and beyond.

[@cernejr]

@@ShawnHymel Thank you.

[@nobody2937]

Absolutely agree...

[@vijayalakshmi-ir5jw]

Well explained one... Thanks for sharing

[@TheAndjelika]

My question. Where is the line in between assembler code (machine code) run by CPU, so when you create your code on that level, interrupts, loops, and where RTOS begins? I have feeling it is somehow in between just machine code and GPOS, a bit advanced than super loops.

[@GrimpeurFou]

Outstanding overview. Thank you!

[@dylansternbeck9230]

My first experience with a RTOS was a lighting console that ran on VXWorks!

[@dankilg4130]

Very interesting. A multi-tasking Computer. Must be a real head- Ache to program. Wondering How many tasks can be performed In real time. Must be like dealing With a woman. Gods only real Time biological multitasking Creature.

[@bertbrecht7540]

This is top quality content. Thanks!

[@dougsteel7414]

There are instances of asynchronous execution within a super loop. Either by calling inbuilt functions or using command patterns, although I guess functionally they're no longer a loop even if they are structurally

[@MKDas]

Really informative and helpful.

[@StephenMattison66]

Great video, great audio, thanks for the smart lapel mic!

[@webfreezy]

Well, the music is too loud compared to the voice, otherwise it's ok

[@StephenMattison66]

@@webfreezy No, it's great!

[@tommymairo8964]

5:08 You don't need to use multi-core processor for concurrency. If you have interrupt supported by hardware, why don't you use an external timer which fire interrupt every 1ms? So you could switch to the next task after the current task's quota expires.

[@YourCRTube]

This is _exactly_ how FreeRTOS works.

[@outlookha3330]

Waiting for the next video!

[@bennguyen1313]

Does an RTOS' delay function (ex. FreeRTOS' vTaskDelay()), allow the scheduler to run other tasks? Actually, even if a low-priority task sits in a tight while(1), isn't the whole point of an RTOS to have the ability to wrestle away the CPU after too much time? I have a motor control application, and would like if a task receives a command in the queue, it will move until it reaches the destination (30+ seconds). If another command is received while it's moving, it must stop and go to the new position. Maybe the task could look like: wait for queue command start motor moving Continuously check position and stop when reached OR stop when new queue command is received Would monitoring the position block/starve all other tasks? If so, what's the proper way for it to closely monitor position while still allowing the RTOS to run other tasks?

[@endofficecolo6850]

@Digi-Key, do you have that keyboard for sale by any chance?

[@ShawnHymel]

I don't think they do. It's a Varmilo VA87M, if you're curious.

[@penguin1714]

Thank you for making these videos!

[@hithere2561]

Thanks, great video but do you mind to turn down the music volume at the beginning - its waaaay louder then rest of the video

[@ShawnHymel]

Thanks for the heads up! I'll work on getting the volume down of that intro/outro music.

[@ultraderek]

I just set up some peg board in my workspace. I use so many freakin tools doing robotics and other mcu projects. I kind of wonder why I haven’t already been using peg boards.

[@ShawnHymel]

Right?!? It took me a few years before I decided to put the pegboard up. It's incredibly handy!

[@kennethcarvalho3684]

why not use an arduino uno?

[@ko-Daegu]

What do I need to be to understand this series cuz I got no electrician engineering background

[@ShawnHymel]

You don't necessarily need a degree or be in any particular profession. This is an intermediate/advanced topic related to embedded systems. I recommend having some experience with Arduino and C/C++ to understand this series. There are lots of videos and courses out there to get you started with Arduino.

[@mav29]

so well explained love this video

[@NoProblem76]

How does RTOS compare to coroutine?

[@ShawnHymel]

Most RTOSes (like FreeRTOS) use pre-emptive scheduling, which allows tasks to interrupt other tasks whenever the scheduler decides to do so. In some RTOSes, you can turn off pre-emptive scheduling to turn it into cooperative scheduling, which allows you to use coroutines.

[@cyborglabs2272]

thanks,,,,, very nicely described,,,,, one thing missing was the example of some rtos

[@shuewingtam6210]

You said RTOS can do multitasking but what is the difference from multi core cpu, that can also do multi tasks with core funtioning individually?

[@ShawnHymel]

Great question! A multi-core processor is something that's done in hardware: it allows you to run code concurrently on separate cores. An RTOS (or most OSes for that matter) can make it seem like you're running tasks concurrently (even on a single core) by rapidly switching between tasks. I recommend watching Part 2 to see how that's done. Some OSes are configured to handle multi-core systems, so you can have multiple cores that switch among tasks (all running on top of the same OS). In Part 12 (to be released), I show how you can use FreeRTOS with a dual-core system.

[@LL-ue3ek]

good video, need to crank up the volume a bit.

[@kayakMike1000]

Scheduler is kinda the core of an RTOS... loading/unloading/start/stop/suspend/resume tasks is core RTOS. Interprocess communication comes next.

[@educationaltechnology8363]

whats is pwm is called task thread or process and how fast will it excute during multitasking? with more pwm?

[@ingenierocristian]

Howdy, I understand the need to present these topics in a digestible and simple way, but could you please tell me where can I find more info?

[@wahabfiles6260]

so basically in normal OS scheduler is non-deterministic while in RTOS its deterministic?

[@ShawnHymel]

Yes--that is well summarized. Note that heap allocation and access can be non-deterministic as well, which is why FreeRTOS lets you choose the heap allocation scheme (www.freertos.org/a00111.html). I talk about memory management and touch on this in a future episode.

[@wahabfiles6260]

@@ShawnHymel maks so much sense! subscribed to your channel as well.

[@sexygeek8996]

If you want deterministic performance you should avoid using the heap, other than allocating everything you need on startup. Dynamic memory allocation is grossly overused nowadays.

[@BDYH-ey8kd]

You can run concurrent on super loop if you divide the tasks in switch statements and design non blocking, but this requires some years of experience.

[@moiquiregardevideo]

The "divide tasks in switch statement" is what many call "state machine". More precisely, a hierarchy of state machines where each switch statement could be seen as a tree structure when matching the call tree.

[@sanmitram4172]

Awesome video.. 👍🏻👍🏻 Thank you..

[@tonysofla]

You did not mention state machine cooperative multitasking, a task doesn't hog the system but instead do snippets and then for example tell schedular to come back in 250ms with the option that a tasks IRQ can tell the event handler to run this task "right away" I wrote my own in 50lines of C code. example of usage: OS_Interval_Next(this,5*1024); // give it 5sec time before turning off swclk pin

[@pietheijn-vo1gt]

How does a super loop compare to a state machine? Or is a state machine a kind of super loop?

[@shawnhymel7647]

Neither. A state machine is used to determine what kinds of actions should be performed at any given time based on the “state” your program is in. Usually, this is just something like a global variable that stores a number, which tells you what state you’re in. You then employ a switch/case statement to perform different actions based on that state (i.e the number stored in the variable). Anything can cause a state to transition to another state (e.g finish executing one state, a button press, a timer, etc.). You can use a state machine inside of a super loop or in an RTOS.

[@ArjanvanVught]

@@shawnhymel7647 When programming with a super-loop than for example, a TFTP server must be implemented as a state-machine. In an RTOS there could be a blocked wait of requests, the RTOS scheduler will do the context switch. In a super-loop, there can never be a blocked wait.

[@ArjanvanVught]

@@shawnhymel7647 "

[@aligasco7206]

Hello reference height I want to know my room floor level how much height from other room in which video solution

[@bobp5776]

Is it possible to run a I2c device in one of them Tasks ? So far i haven't seen any examples of that. ie. as5048 Position sensor running on one core and making its Angle data available globally to the other core..I cant get it to work.

[@haraldhwick]

How did I wander here? I was just watching documentary on ICs. This is interesting though :)

[@WagonLoads]

I have been running into a situation where I need something to be timed. The problem, is when the timeout occurs at some point in time when the loop is doing another process.. Let's say the loop takes 11 to 14 seconds to repeat and I want my screen to stay lit for 90 seconds.. I can't guarantee when the loop will check when the screen timer reached 90(not after). It can only tell if the set time has gone past the timeout.. (Just like your piston catastrophe reference). Is there anything like a timer interrupt?

[@paullee1792]

Is that open source operating system?

[@pipoyII]

Thank you Shawn!

[@SMAH-qx2jv]

is it possible to attach a encoder running on 1500RPM and at the same time its reading data from ADC?

[@RinksRides]

not firing a spark plug = not a big deal, misfiring at the wrong time COULD be catastrophic though.

[@ShawnHymel]

Good catch, thanks :)

[@shivrajp9686]

Hello sir, when i remove while(1) in toggleLED function, behaviour is same. does free rtos schedule same task again and again. here is the code i used #if CONFIG_FREERTOS_UNICORE static const BaseType_t app_cpu = 0; #else static const BaseType_t app_cpu = 1; #endif static const int led_pin = 2; void toggleLED(void *parameter) { gpio_set_level(led_pin, 1); vTaskDelay(500 / portTICK_PERIOD_MS); gpio_set_level(led_pin, 0); vTaskDelay(500 / portTICK_PERIOD_MS); } void app_main(void) { gpio_set_direction(2, GPIO_MODE_OUTPUT); xTaskCreatePinnedToCore( toggleLED, "Toggle LED", 1024, NULL, 1, NULL, app_cpu); while(1) { ; } }

[@dabay200]

Nice video but you need to improve the sound quality - the voice level is too quiet and have ramp up the volume quite a bit.

[@chaitanyakanagala7950]

Great work 👍

[@bobdalah8374]

Hi, your documets on digikey are not accessible, how to access to them?

[@RegisMichelLeclerc]

On the principle, you can achieve all of this in a "superloop" by making sure every instruction will execute in a limited amount of time and will never hog the MCU to itself. For instance, when repainting your LCD screen (say, a 5110 LCD of 84*6 bytes), you could block the entire processor for the time to repaint the entire screen and call the function 20 times per second (you're going to kill yourself waiting for the RDY pin of the screen to become high), or repaint the screen one byte at a time and call the function at every loop (returning immediately if the RDY pin is low). Same goes with buttons, you check the state of the button once per loop instead of hogging the CPU with insane debounce delays, It's just a programming style, what's the point of adding a greedy layer of RTOS (in terms of time and memory) instead of accepting the challenges from the limitations of the processor?

[@moiquiregardevideo]

For that example, RTOS are overkill. I may update more than one byte but not the entire screen on each calls. Maybe a cache could be best if RAM is many order of magnitude faster. Your code paint to a RAM buffer fast fast. Then, the paint compare if anything is different and update only what changed. The RTOS become necessary when the device must access wifi, ethernet, all brand of SD flash memory and all USB hub/mouse/keyboard/thumb drive that ever existed.