ฝัง
- เผยแพร่เมื่อ 24 เม.ย. 2020
- When you write Arduino code, you usually split your code into two parts: the setup() function that runs once, at the beginning of the program, and the loop() function that runs repeatedly. But did you know that it doesn't always have to be this way?
In this video you will learn how to write Arduino code without setup() and loop(), and see some of the benefits that come with it (such as reduced code size), as well as some solutions to common challenges with this method.
Arduino Port Registers Reference:
web.archive.org/web/202108130...
Arduino main() function source code:
github.com/arduino/ArduinoCor...
The code from the video:
wokwi.com/projects/3307127700...
The Arduino Blink Playground:
wokwi.com/arduino/libraries/d... - วิทยาศาสตร์และเทคโนโลยี
![พรากรัก - เต้ย อภิวัฒน์ [ Official MV ]](http://i.ytimg.com/vi/ShT2ltn8GBE/mqdefault.jpg)
For those who want still smaller, here is an assembly version that fits in 14 bytes:
#include
#define io(reg) _SFR_IO_ADDR(reg)
sbi io(DDRB), 5 ; set PB5 as output
loop:
sbi io(PINB), 5 ; toggle PB5
ldi r26, 49 ; delay for 49 * 2^16 * 5 cycles
delay:
sbiw r24, 1
sbci r26, 0
brne delay
rjmp loop
Build it with `-nostdlib` in order to prevent the linker from adding the interrupt vector table (104 bytes) and the C runtime (28 bytes).
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,
If you want for further memory saving. Try use assembly language and keep in mind that it will really give you headaches as you need to know the register memory address for every pin and interupt that the microcontroller had. So in real life situation, what is the benefit from this memory saving? Is it make the code run faster? Made it work more reliable? More stable? Well, my motto is, memory is there to be use and make your life easier. So use it as what it intended to be.
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.
Using internal timer interrupts is more efficient and accurate for blinking an LED. Especially when you try to do something else aside of the blinking, which can make the LED blinking a bit slower as more instructions are executed after the blinking lines.
Or for more efficient for some more tasks and the ease of use, FreeRTOS can be used. You just need to create the task, using the internal task delay method that is similar to the delay method although it might not be so optimised if you are trying to implement some simple applications like “blink”.
wow, main() will be my new skills that I can put on my resume!
My main() skill is optimizing 😉
and asm("");
Really good optimization's without leaving the Arduino ide. Pretty neat!
Thank you so much for this great, high-quality tutorial :)
Arduino was invented as a platform for beginners on a microcontroller. And so everything complicated was hidden in the library. The great advantage is, you can start programming without reading datasheets and understanding the inner structure of a device. Because for beginners, this can be rather frustrating.
The arduino-platform is ok for smaller projects.
But if i want to use the full periphery of the controller and have to optimize for speed or memory-usage, i prefere the Atmel-Studio and coding in Ansi-C or even in assembler. The advantage is a much better use of the resources, but i loose the independence of processortype and i need much experience in debugging, especialy when using many nested interrupts.
So, both approaches have their raison d'etre😊
There are thousands of ways to let a LED blink with a Microcontroller, but this in not the intended use of such a device.😉
@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:
th-cam.com/video/mDhNQPt8An0/w-d-xo.html
Wow I didn’t know that this was possible. Awesome!
Mind blown!! Here I was thinking that for more complex projects I'd have to do something crazy like break out sections of the code to multiple arduino units for the sake of storage and memory, but your video has shown me that I need to be more versed in my computer languages. Thank you for this!
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.
liked it ! very enlightening, I will follow your videos. hugs from Brazil !
Thank you David!
Great video. I use those low level registers to control WS2812 LEDs with my own code rather than the libraries.
I figured out a while ago I could use main() like we normally use in C/C++, but the delay and other functions didn't work. Your video shows why. Thanks!
So, if I write my own main() and then add in init(); initVariant(); and USBDevice.attach(); up front in it, I can then use it with any Arduino function [ like delay() ] just like we do with setup() and loop().
This is great! I teach Summer STEM and I want to show my students the normal main() entry point for a more general C/C++ expectations with most compliers.
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, very interesting analysis!
Great simple descriptive video.
If ever redone in.a newer video: The sizing comments should include a description of what the mods were, and the operating result. Also would be nice to know what the empty loop time elapsed is, measured. You can use a stopwatch and and outer loop to lengthen the time to that which your fingers can operate the stopwatch to some good accuracy.
Thanks for sharing, exellent idea!
This is like using C code but without the Arduino "runtime" (if it can be considered as a programing runtime) and the same if you make some an aplication for windows but without the C runtime.
Really cool.
Amazing, thank you very much :)
Usefull to know... I did once hit the space constraints of an uno but have since jumped to a controller with built in wifi and more room so the problem went away. Might come in handy though if I ever go back to using the uno with the ethernet shield for something else.
The comment section shows great interest in this video. The point of the video is "Optimizing" .
I suggest that you optimize the use of the screen space (width) Roughly 30% is wasted in two black voids. Further the width of the info block on the left could be reduced by half and still maintain its purpose.
These changes would allow a much wider area for the code block and a larger font would make reading the screen possible. I enjoyed the video but gave up trying to read the text because of the illegibly small letters. Oddly the least important text in the info block is more legible as it has a larger font size. Thank you for not using any distracting music.
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
I think you can create a delay function of your own, and use it whenever you need some delay. To protect the for loop getting pruned by the optimization process, you could have used volatile keyword for the function. It may yield a smaller footprint (I have not tried myself). The same volatile keyword approach can be used for interrupt service routine functions as well.
In C you can not apply volatile keyword to functions
@@brinza888 Arduino uses C++ I think, not C
Cannot thank you enough wokwi..this delay removal tool is easier than millis()...thumbs up for you
Hi! thanks for the video, it is very useful information!
I have a question, the link you post about "Port registers" talks about ATmega8 and ATmega168 microcontrollers... Is "Port registers" possible to use with mega32u2??
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
In the book "Programming Arduino; Getting Started with Sketches" by Simon Monk, he mentions "main". I just unsuccessfully tried to find the page but that is all he does, mention it. Interesting video, subbed...
Thanks!
One of the purposes of setup() and loop() is ease in programming for new coders. And function delay() offers accurate time delay. Your code is mix of low-level register access, and inaccurate delay using simple loop. If I want a 200ms delay, your coding would be inaccurate.
If you want optimization I think you go for assembly language coding.
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: th-cam.com/video/tnfeMCyLZSo/w-d-xo.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.
Berry nice. I don't need it now. but it is good to know
Would the percentage reduction be nearly as large if the program had started out to be 5000 bytes? It seems like you would reduce it by the same number of bytes when you eliminate setup() and loop().
That's right Owen!
And what about compiling the "optimized" code to, for example, an STM32 Arduino-compatible board? Do you think, this is really a good way? I think this way is "good" only for dropping any portability and stucking into a very specific hardware. Moreover, if you want to write effective code to a particular hardware, than you can drop also C language and do it in the hardware's assembly. But, I think, Arduino's concept is rather the opposite of this and it better wants you to make code that can be portedto as many hardware environment as you can imagine for the task.
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.
Interesting video, thank you
amazing video, thanks
wow , amazing
You could use volatile long in your for loop, idk about asm() so don't know if that's more efficient
Good tip!
Thanks! Its wery usefull
Спасибо. :)
Очень интересное видео.
thank you very much❤🙏🏻
👏 amazing video 👍
Very good i love arduino projects
We love them too!
You make my day
it is possible to reduce code by another ~128 bytes. First chunk of Flash memory is occupied by interrupt vector table and stack initialization. If we do not use interrupts then our code could start at address 0 without jump instruction to skip other interrupt vectors. A lot of instructions is wasted to make a delay, I have a suspicious that setting a timer and toggling pin in an interrupt function could lead to a much smaller code.
Thanks for the tip!
Great video sir.
Can I2C Communication Components such as LCD 12C or Oled use this port manipulation?
Good tutorial! And good english! Slow and clear! Ideal for spanish people.
Muchas gracias Jose!
How do you move text up and down with the keyboard like that? I tried several combinations of ctrl, alt, shift and the arrow keys, but couldn't replicate the behavior in SciTE. Is it unique to Arduino IDE?
Alt+Up or Alt+Down. This works in editors derived from VS Code, such as the editor Wokwi is using.
@@WokwiAh. Thank you
Optimizing code is good. However, premature optimization can waste a lot of time on something we really don't need or may not benefit from. Thus, the saying "Premature optimization is the root of evil, -Donald Knuth".
So we build something that works first then examine it later to find out areas that need optimization. 😉 Anyways I've learnt something new from this video. I am from a web development background with php and c# and I'm new to arduino
Yes!
What about long push and looping menu system that jumps to different menu loop after long push.
Premature optimization is the root of all evil :))) lol. Good video tho!
Thank! Yeah, I should have said that at the end :)
Would this optimization interfere with UART communication protocols if I were planning to connect the Arduino to the Raspberry Pi and send data packets to and fro the 2 devices?
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.
Shouldn't the compiler do the optimization during compile time? If there's no need for dynamic memory allocations.
I never really used more than 50% mem on an Arduino program, but I don't doubt there are engineers/developers who will want to squeeze it as possible. Technically this video is very good
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.
Very interesting, but I wonder if the idle loop would consume more power then delay function, as in many architectures delay or waiting is done by halt the cpu until woke up by the timer, is truly do nothing; while the "do nothing" loop are actually doing something to count the loop and branching back continuously.
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).
Hello from France, really very interesting, is this applicable to attiny85? In the Arduino documentation there is nothing about these subtleties?
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
I would really like to see an demonstration on how much of a speed gain we can achieve as a result of these kind of optimizations.
nice work . go ahead.
Thank you. I think that you have the deep programming knowledge. and you may help me solving my problem.
I want to turn ON an LED for a definite time with a button, by using an ARDUINO UNO R3, even I hold the botton more than defined time. In short, I need one puls every time. I can do it a resistor and a cap at the input of ARDUINO, but I do not want to use any passive component.
Could you help me? Thank you in advance...
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.
That was interesting!
The overhead of the approx 800bytes and a few bytes of dynamic, is this a fixed overhead or does that overhead grow as the user sketch grows?
It may grow when using additional library functions (such as the Serial library).
Hello, This was something I hadn't seen before. Writing PINB toggles all bits (i.e. 0xFF). That part wasn't clear from your narration, "totals the pins". PINx is considered a read only register in Atmel docs. Thanks.
when you called that "for" function, how much time does it take to increase that i variable by one?
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: th-cam.com/video/tnfeMCyLZSo/w-d-xo.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.
it is not 'optimization' it good explanation how Arduino framework works inside, he stripped out most of arduino )))
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. 😉
I wonder where can I find the port registers reference now... the link in the description does not seem to work for me, and I can't seem to find it on Arduino's official references
I mean, I sure could use one of the tutorials I've already seen in the internet, but the official documentation would be nice. I wonder why they removed it
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.
Does this optimizes only the memory utilized or also increases the speed of execution?
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.
That's great
I had a feeling there is a way to optimize code.
How do I print lcd values and control stepper motor in same loop without causing delays to stepper motor
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. 😅😅😂
Hi, how can I insert a simple diode 1N4004 or transistor 2N3906.
Does wokwi support adafruit boards? I have the adafruit feather nrf52832 with the m4f.
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
It's like going back to complex embedded coding from eaiser one. It negates the purpose of using Arduino :D. That's what I feel.
A good solution would be to use a cheap, but well built Arduino hardware, remove the Arduino bootloader and use it as a regular AVR board.
Right, it helps you appreciate how much Arduino is making our lives simpler
What about incresing code? 924 bytes is preloaded arduino.h content, which will be used for building bigger code.
yes I have a question: (kinda more a request): how would you achieve individual pin control? and pwm?
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
Im wondering why PINB can be assigned with the value. I thought it was read only ;)
Nice insight. Still, complex code would be difficult from scratch.
I love your videos
basically, if you want your code to optimize, u write it at a lower level, like you are using the mcu directly. That's also what I ve learned when i stepped into the stm32 community.
bravooooo👍
Nice👍
Smaller but at what price? Readability, which directly effects maintainability! Part of the purpose of the Arduino IDE is to make programming easier, especially for the beginner. There are plenty of microcontrollers on the market so if you need more memory or more speed buy a different one. If one needs to minimize size then write the code in the assembly language for the target device and document it well but don't expect it to be easily understood by a wide audience.
You just got a subscriber after watching this video...!! 🙂🙃
and can I ask a solution about a problem...!!??
Can we run two different functions simultaneously as driving 2 to 4 stepper motors and doing other things like Marlin (3d printer firmware) does .?? actually I need ro make a small firmware for running stepper motors and displaying data like temp speed and menu kind of thing just like Marlin but for other kind of machine that will basically do the some kind of repeated movements according to the values set in menu..??
Please help
Greattttttt !!!!!
inside the for loop you can write ; which is an empty statement ,then the compiler would never ignore the for loop, or a better solution could be by moving the increment of i to the loop:
for(long i=0;i
How it toggles
PinB = 0xff;
Means it should be high always, right?
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.
Any ideas how to faster analog read?
Hey. I have stuck in a problem.. is there a way to discount hc05 connection automatically after some time?
Hello Ahmad, you can try sending at "AT+DISC" command from the Arduino while the module is in AT command mode. Not sure this will work, but worth a try!
I always just use _delay_ms(1000) instead of delay(1000). The compiler knows exactly the for loop to jam into your code based on the frequency of your target board so timings remain accurate. And the compiled code is still tiny and readable without being bloated with Arduino stuff. This also compiles to 158 bytes and 0 bytes of DRAM
int main(void) {
DDRB = 0xff; // Set pins 8-13 to OUTPUT
for(;;) { // Loop forever
PINB = 0xff; // Toggle pins 8-13
_delay_ms(1000); // Do nothing for 1,000ms
}
}
how about expanding the arduino program memory using hardware. in the other hand we keep the programming fun and easy.
Wokwi the best simulator for Arduino and esp32..I was surprised I was able to simulate freertos too 😯.
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.
using main() function how can be used drivers for different modules and EEPROM memory?
Some of them will work out of the box, and some will need some extra code that sets up the timers so that delay() works correctly. But as many people commented, we wouldn't go with our own main() in most cases. setup() and loop() do the trick well for most programs, and the idea of the video is to learn how things work behind the scenes, and also to learn to appreciate the convenience of the Arduino standard library, Wiring.
Thanks
that is what libraries do: trade overhead for readability and easy of use. I don't think it worth to go quasi-assembly to save some hundreds bytes, but it is a nice exercice though
Hello, can you recommend a book which talk about this subject but deep? Thanks!
Unfortunately, I'm not aware of such book. If you find one, I'd love to know too!
@@Wokwi I just ordered "Avr Microcontroller and Embedded Systems The: Using Assembly and C", I think its the most related to the subject, what do you think?
@@mangostain Haven't read it, but it sounds relevant! If you are interested more in the electronics part, I did read Electronics Cookbook by Simon Monk which was pretty nice, and also heard good things about "The Art of Electronics", but haven't had a chance to read it yet
replace delay with for loop is replacing ugly with catastrophy.
how can we do it in a esp32?
Good day, can you help me with the code for 4x 12v car battery voltage monitoring with ESP32 home
Poderiam fazer um app para Androi, estou muito empolgado com esse simulador!!!
The Arduino-Framework relies on the fact, that the loop()-function gives controll back to the caller from time to time. If you don't want that, don't use it at all. For Atmel- and Pico-Microcontrollers there are plenty of cross compilers available.
BUT you have to keep in mind, you have to take care of all the hardware- and interrupt-handling-setup yourself! It makes binarys smaller and gets rid off a whole lot of stuff, that you probably don't need. But this is far from beeing trivial. You have to know about hardware-registers of the specific µcu, you are dealing with and manage them yourself.
Like I said, far from beeing trivial.
The active waiting saves space but definitely is not optimal in terms of energy consumption
How can we add additional library in wokwi and components... Also let me know website to test raspberry pi 4 model B semulator online ?
For libraries, you can use the "Library Manager" tab. For components, there's a new "Custom CHIP API" that is being developed. Look out for documentation over the next few weeks. Raspberry Pi 4 Model B simulator - not something that you are likely to find online, as it's too demanding to simulate inside a web browser.
Machine code is very efficient. No nonsense. Also incredibly unreadable. I for one throw away the idea of saving space. If I run out of space, then I chose the wrong MCU from the start. My first MCU was the arduino Due. The setup and loop really comes into its own when doing dual core coding with setup1 and loop1. Is brilliant for beginners like myself.
i would like to learn how you edit your code, your copying and pasting, selecting, and editing text is very efficient. Greetings from Argentina.
You can find some of the keyboard shortcuts here: docs.wokwi.com/keyboard-shortcuts#power-editing-keys
@@Wokwi thanks but i found that pressing F1 on the ide shows you everysingle shortcut and im playing with it, i hate using the mouse idk why, it doesnt feel right.
@@jonayamaha3215 Even better!
How to open "Program running" window (with "Sketch uses ..." information)?
Too much interesting
Back in the 70s, memory was expensive so we had to optimize byte usage by using inline assembly, bank switching, etc. I can't believe in 2024 where memory is cheap and plentiful we're still trying to save bytes!
The looong loop for nothing with cap 0-499.999 is not represent one second accurately, and will it be longer if the code is much complex?
That's true! To represent one second accurately, you could use the timers. If you want, we can post a demo for for that too.
@@Wokwi timer?
@@LexBarun yes, that's also how delay() works behind the scenes. Here is an example that uses Timer 1 to blink the LED every second:
wokwi.com/share/GW8g3bgG5ooEcx2fWCH1?
If you are interested, you can learn more about this in the following blog post, look for the section that says: "Blinking with Timers"
blog.wokwi.com/5-ways-to-blink-an-led-with-arduino/?
Wow! I'm impressed.
Is there a book or an online course for more?
You may want to check this free online course: th-cam.com/play/PLLomdjsHtJTz4st9xzb5qrqWAAatEzq-g.html
int main(){return 0;}
?
So you are using CPU up to 100% in for-loop to save a few hundred bytes of memory?
Have you ever looked up how delay() is implemented on Uno? 😉
@@Wokwi by physical timer chip I guess?
@@caunt.official Busy loop that calls micros() repeatedly and compares the return value with a variable...
github.com/arduino/ArduinoCore-avr/blob/63092126a406402022f943ac048fa195ed7e944b/cores/arduino/wiring.c#L106-L117
@@Wokwi didn’t know, thank you. I am moving into microelectronics from desktop and backend development, and it’s a bad practice to delay something with for-loops in OS environments 😅
@@caunt.official You're welcome. This is also true for embedded development - modern embedded OSes (like FreeRTOS) implement delay more efficiently. Delaying with a for loop consumes more power, so for battery operated devices, efficient delay is crucial.