NICE..!! Im learning assembler and I love it.. :3

@@emanuelh.a8492 :3

how is the c runtime so tiny only 28 bytes?

@@mikoposter: * initialize some CPU registers (r1, SREG, SP): 12 bytes * call main: 4 bytes * jump to _exit: 4 bytes * implementation of __bad_interrupt: 4 bytes * implementation of _exit: 4 bytes That's 28 bytes total. If the program has a .bss section, add 16 bytes to zero that part of the RAM. If it has a .data section, add 22 bytes for copying it to RAM. This program doesn't use any RAM, but most non-trivial ones do have both a .bss and a .data section.

I had already try the same asm code and find that when substracting 0 with carry does not set the Z flag when r26 goes from 1 to 0. (At least in the Atmel Studio simulator). Instead I have to use: brnc delay , since the Carry flag is set when r26 goes from 0 to 0xFF,

Thanks for the reply Denny! Agreed, when you have memory then definitely use it. In our opinion, optimizing is not all about the code size/execution speed, but first of all making good use of your time as a programmer, and saving headaches for people who come to maintain the code in the future (including yourself)

Not using loop() actually does increase looping speed and using direct port management increases blinking speed hugely. With Arduino libraries I was getting about 250KHz maximum pin toggle speed while using direct port management and no loop() toggle speed was approximately 5MHz. That is 20x speed improvement! More than that using direct port management we can read and write multiple pins simultaneously further increasing speed. In operations like decoding encoder pulses that will be roughly 40x speed optimization.

Some comments are saying to just go ahead and use the memory that you have. But then when the new PSI42-69 chip comes out next year, you may find yourself having to write a new version of the program that needs exactly that "unneeded" memory. KISS with clean and secure code.

I mean, we're not talking C++ here. Most of this is very well translated 1:1 thru the interpreter. Not much will be saved hand writing the asm in this situation

@@CrispyCircuits The best approach is a combination of both ;) Write with the technics which gives faster TTM/more structured and supportable code - and optimize/rewrite in the low level only the parts you really need to.

My main() skill is optimizing 😉

and asm("");

@charly_a8654: "There are thousands of ways to let a LED blink with a Microcontroller, but this in not the intended use of such a device" Meanwhile in my head: ukposts.info/have/v-deo/pXSZgoeHq25yz2Q.html

Thanks for the feedback Andre! Yes, totally, the accuracy of the "home-made" delay can be improved. This actually give me an idea for another video, stay tuned :-) Have you ever used assembly language in your projects? For which parts?

Hey ​@@Wokwi! Did you make that other video? :) (I'd be really interested in using efficient delays, for me, precise time intervals are really important, with using _delay_ms() for example)

@@rafa_dzto Yes, you can find it here: ukposts.info/have/v-deo/rJ6XmYN6sIKLtKM.html

@Andre Nixon Delgado Not completely true. While it is inaccurate with this cycle delay, it is not that much of a challenge to setup a timer for 1kHz frequency yourself (or any freq. which required in the project for other tasks), and make your own delay. It won't need half k of flash, and you might use that timer for several other timings. If you are not just blinking LED, but do some more advanced high-performance stuff, then interrupt handling, and utilizing that few timers that are in the core is a must. In a properly written automation code, there is not that much of use in a synchronous blocking delay function anyway as usually only the UI runs in the main thread and that usually waits for the user and updates the display, which is usually not quite wise to be delayed (for more than 10-50ms or so, it depends).

I agree with Angelo. Arduino API is for fast fun with electromech stuff. I coded for hardware users, giving them APIs built on APIs to get them (litterally) flying. Once they were aware of the environment, I showed them to the minutiae of the lower and lowest level code for tight control and timing. I am happy with Arduino's method. It makes coding widgets fun again.

if that's your problem why don't you just use ESP32 and all of a sudden you have more memory and delay doesn't block your program anymore

@@martinkulizadelay still blocks the program actually, you need to use freertos task for that purpose actually... and its harder and less intuitive than using millis() or delay()

@@nintendero65 Actually delay doesn't block the program and Actually it's not harder that millis and Actually...... You seem to like the word "Actually" DO YOU UNDERSTAND WHAT THIS WORD MEANS ? It means if something ACTUALLY IS a certain way Example : The reply button here in you tube ACTUALLY IS BLUE, if i said it was Red, You could say ACTUALLY IT'S BLUE and that would be a true statement Now... in FreeRTOS and it is FreeRTOS not freertos, "delay()" DOES NOT .... ACTUALLY Block the entire program. where as in Arduino it does so... delay using ARDUINO IDE will block the program vTaskDelay() Used in FreeRTOS DOES NOT block the entire program and when you use delay() in FreeRTOS the compiler converts delay() to vTaskDelay() and therefore it does not block the entire program TRY IT create 2 tasks 1 that blinks a red LED 1 that blinks a blue LED have them both run at a freqeency of 300ms but put a delay on the blue led for 5000ms SEE IF THE RED ONE STOPS...... LOL.............. IT WON'T in Arduino it will when using FreeRTOS it will NOT Because using delay or vTaskDelay in FreeRTOS only delays that task, Not the entire program HERE READ THIS TASK STATES www.freertos.org/RTOS-task-states.html RE "you need to use freertos task for that purpose actually" What did you think i was talking about ? "and its harder and less intuitive than using millis() or delay()" The Entire Language of C++ IS NOT INTUITIVE THAT'S WHY THERE IS A 400 PAGE DOCUMENT ON IT if Arduino and C++ was intuitive - No one would need to watch a you tube video - No one would need to ask "How do i make this LED blink" or "I connected my board but the sketch is not uploading" or "I've done everything right but my code doesn't compile" WHAT'S INTUITIVE ABOUT C++ IN THE FIRST PLACE ? Also WHEN COMPARING vTaskDelay() or just delay() and you only need to enter the number in the parenthesis HOW IS THAT HARDER Than going through millis and putting all that code in No mate, delay() is a hell of a lot easier in FreeRTOS in FreeRTOS you don't really have a reason to use millis, millis was always a band aid solution anyway

@@nintendero65 I think he meant that you avoid the delays when communicating between multiple MCUs if you have one MCU that's beefy enough to run your entire program.

Good points, thanks for the feedback!

Are you watching on a 4" 21:9 screen? If so, get a grip... if not, get a grip, your complaints are not valid. The trend of using overly large fonts "for people on mobile devices" has gone so far that I can't even watch some videos in fullscreen anymore, or have to move back like 10' to be able to read anything at all. Beside, how do you read the comments, horizontally scrolling because you have to zoom in so far? The video is utterly pointless anyway XD

Awesome! Where do you teach?

@@Wokwi I am retired here in New Hampshire. I only take 6 students over the summer: 8 hours a day, 5 days a week, for 8 weeks. I interview all the parents and students together. I don't go by grades but by aptitude and eagerness to learn... and it's free! Except for the price of the project/kits which each student keeps. My angle is "Don't let your kids play video games all summer, get them a head start on being a scientist/engineer/technician and focus on STEM all summer". The parents love me because I stay away from all the "woke" nonsense they teach in public schools these days. I tell each parent/student that we ALL say the US Pledge of Allegence before we start class each day. This ourages the liberal troublemakers and thus I pass on selecting their child for my class. One parent tried to sue me because she claimed I was indoctrinating childen. I said no, the pledge is just a form of solidarity, if you want indoctrination, then go back to the public school system. My lawyer shut her down instantly. It's my house on private property, I set the rules and tell everyone what they are, you and your child have to agree to the rules which are legal, parents can tune in and watch/listen to the class at any time (I covered the On Air LEDs on the cameras with tape so I never know when parents are watching), and I do not charge a fee, the students just pay for the cost for their projects that they keep. Some parents want me to deprogram their children from the brainwashing their children get in public schools, some even offer a nice paycheck, but I tell them no, I will stick with just STEM. The pledge is just to weed out those with closed minds or demand EVERYTHING in the world is done their way. The parents that do just that get so annoyed that their child with straight A's and is a perfect bleeding heart spreading their adgenda was not selected. I once had a student that was here from Mexico on a visa. His parents said they were not comfortable with the US pledge because they are not US citizens. I told them, ok, your child will sit quietly while the rest of the class stands and recites the US pledge, then, the class will sit quietly while he stands and I say the Mexico plege WITH HIM in Spanish. The parents loved me, their son was a wonderful student.

Thank you David!

Yes!

In C you can not apply volatile keyword to functions

@@brinza888 Arduino uses C++ I think, not C

Right, it helps you appreciate how much Arduino is making our lives simpler

Hi Zoltan, thanks for your comment! Yea, this makes you appreciate the simplicity of Arduino, and portability, as well as the huge ecosystem of third-party libraries, code, and tutorials is what makes Arduino so powerful and amazing!

Arn’t cpu map libraries, such as in grbl and marlin, the answer to portability when using port addresses? Am I missing something?

Dropping C in favor of ASM made sense some 10-15 years ago. Nowadays it's very hard to write better ASM code than what the compiler will generate from C.

@@sharpfang - For me, writing C is torture because I don't know how to view the resulting assembler code, so I'm left to guess what my code does. That's only a problem in a small number of cases but they are very important. For instance, when I turn off interrupts for some critical code, I don't know enough to be sure the optimizer isn't going to relocate some of that critical code outside the uninterruptable section.

@@jrstf You can use `objdump -C` to get an assembly listing of your compiled code, intermixed with the original C statements. This shows very clearly what the compiler does with your code. Not something I would do everyday, but it is handy for this small critical cases. Also, for critical sections on AVR, you have the avr-libc macro ATOMIC_BLOCK.

We love them too!

Yes, the ATmega32u has even more port registers, going from PORTB to PORTF. You can find the complete information in the data sheet: ww1.microchip.com/downloads/en/DeviceDoc/Atmel-7766-8-bit-AVR-ATmega16U4-32U4_Datasheet.pdf

Good tip!

Thanks!

That's right Owen!

Muchas gracias Jose!

In the case of Arduino Uno, the delay() function doesn't halt the CPU (there's a discussion about this in another comment), so the power consumption would roughly be equivalent. But on other MCUs, it does halt the CPU (e.g. on the Raspberry Pi Pico).

Good point, thanks!

Exactly. I won't call it optimization, I'd rather call it not using Arduino instead, but doing bare metal development. As someone who started embedded development before Arduino was a thing (or even born...), I like to write my own code, and know everything that will happen iside the device. I usually develop mostly interrupt-driven code and it is not that straightforward to write reentrant/multithreading code and it also not welcome that the framework wastes cycles and timers and so on while I could have utilized the whole core by myself. If someone at the point needing this kind of stuff, high performance code, etc. then it is better to leave the Arduino framework behind and start some serious embedded development. 😉

Thanks for the tip!

Alt+Up or Alt+Down. This works in editors derived from VS Code, such as the editor Wokwi is using.

@@WokwiAh. Thank you

Great to hear Danny! What did you do with FreeRTOS?

@@Wokwi I was able simulate all freertos API's such as: queues, mailbox, semaphores(mutex binary and counting), task notifications, interrupts(with rtos),event groups ,timers ..and everything worked smoothly I chose esp32 for the simulations...thanks for the effort you put in place to make this possible ,, you have made prototyping easier.

It would interfere with Arduino's Serial library, since it requires enabling interrupts. It can be mitigated by calling sei(): int main() { sei(); Serial.begin(115200); Serial.println("Hello World"); while(1); } But I wouldn't do this unless there's a really good reason to.

Your projects are really small and simple if you never reach the limit...

@@DrakeOola Personally if I needed more hardware I would use a Raspberry Pi, or another type of controller. Give me an example of any complex project?

@@DrakeOola or libraries being used are very small

With today's microprocessors being so cheap, it makes no sense to spend time optimizing for memory when you can just buy a more capable cpu. But yes, it's an interesting video, and this is common with all higher level languages.

Thank! Yeah, I should have said that at the end :)

You are invited to the discord chat at wokwi.com/discord. Ask the question in the #questions channel and we'll try to help!

@@Wokwi Thank you for the invitation.

Thanks! Which library are you using for the Stepper motor?

@@Wokwi I was using a4988 module So I was creating a pwm signal using digitalwrite and delay function to implement it.

​@@mainaTheMaker check out the AccelStepper library, as it supports sending the PWM signal in a non-blocking fashion (so you can keep update the LCD while the PWM signal is being sent).

You can code by using LPC 2148 microcontroller method , it tells easy method without using any library function by perfectly knowing function of stepper motor

Hi mates! I have just started to learn arduinos, i have completely no idea what u r talking about, but i appreciaye it. 😅😅😂

Writing to the PORTB register sets the value of the output pins in the PB group, and writing to the PINB register toggles them. So PORTB = 0xff; will always set the pins high, and PINB = 0xff; will toggle all the pins.

It may grow when using additional library functions (such as the Serial library).

Thanks! Yeah, the principles are the same. Arduino documentation tries to be broadly applicable to multiple boards, so they usually don't get into AVR-specific things. The datasheet is where you can find (almost) all the information, and there are also numerus blog posts and threads in forums such as AVR Freaks.

thank's @@Wokwi

There are three registers that allow you to control individual pins: DDRx - set the direction of each pin (input / output), PINx - read the value of a pin (or toggle a pin), PORTx - set the output value of the pin (or enable the pull-up register). Replace x with the port name, so for the PBn pins, the register names would be DDRB, PINB, PORTB. PWM is a bit more involved - but look for documentation about the AVR timers (Timer 0 through Timer 2 for Arduino Uno).

Okay, thanks. I'll dive into it. @@Wokwi

Yes, they seem to have removed the reference page from their site. I updated the link in the video description to point to an archived version of that page.

Hi! Wokwi does not simulate the nRF52 at this time, but feel free to open a feature request: github.com/wokwi/wokwi-features/issues/new/choose

The "for" loop does more than that: it also checks the if the new value is less than 500000, and jumps back to the start of the loop. If you just want to measure how much time it takes to increment a "long" time variable by one, check out this video that explains how to measure it: ukposts.info/have/v-deo/rJ6XmYN6sIKLtKM.html And if you want to measure the time of one complete iteration of the "for" loop, you could count the time it takes for the entire loop to run (e.g. by logging the time returned by `micros()`), then divide by 500,000.

If memory utilization is optimized, speed of execution would also be optimize since there is no floating variables.

That's a great question! Next video will be about this exactly :-)

Also loop () and digital write () functions are about 20x times slower than direct port management and not using loop (). So speed increase huge when delays unwelcome.