Printf on a Microcontroller | Embedded System Project Series #19

I add a printf implementation suitable for microcontrollers so that I can print formatted strings to the terminal. Underneath, it calls the UART driver I implemented in the last video. I further wrap the printf function in a TRACE macro to prefix every trace with filename and line number. Finally, I add trace to my assert function, but only trace the program counter (PC) to save space and show how to get the corresponding file+line with addr2line.
0:00 What and Why
3:28 Add mpaland/printf
6:52 Implement _putchar
9:20 Call printf
11:40 TRACE macro
17:13 Verify TRACE
19:10 Avoid format and cppcheck
22:20 Commit
22:58 Fix mistake 1
23:25 Fix mistake 2
24:00 Add trace to ASSERT
28:30 Program counter assembly
29:53 UART polling in ASSERT
32:20 Fix mistakes
34:05 addr2line
36:25 Commit
37:20 Possible improvements
#embeddedsystems #cprogramming #microcontroller
🌍 Related links
github.com/artfulbytes/nsumo_...
interrupt.memfault.com/blog/a...
github.com/mpaland/printf
🌍 Find me here
GitHub - github.com/artfulbytes
Website - www.artfulbytes.com
👨‍💻 About me
Hi and welcome. I'm Niklas, an embedded systems engineer from Sweden. On this channel, I make practical videos about embedded systems or, in general terms, about building and programming hardware.

[@lewiskim9986]

Your Sumobot making series is literally amazing! I learn a lot from your contents. Thx😊

[@nfjeldberg]

Thank you for all your hard work, amazing work and worth its weight in gold!

[@artfulbytes]

❤❤

[@tufanyou]

Thank you for your share ... it is good👏👏

[@tedelctro6849]

Good job 👍

[@olivialinden8699]

Smart !

[@prashkd7684]

Stm32cube ide had those feature baked in . Sprintf can print on jtag aerial port .

[@artfulbytes]

Yes, that's good to be aware of if you are on STM32, can save you some effort depending on your needs. Other microcontrollers + IDEs may also have out-of-box support for terminal printing. Though, it often requires the debug probe (and sometimes slower). UART is a more general approach in some sense.

[@sfnembedded]

Wow thanks for the tutorial! Can you share which IDE do you used?

[@artfulbytes]

No IDE in this video. I'm running Ubuntu with i3, vim as my editor in the terminal alacritty. I describe it here www.artfulbytes.com/devenv.

[@sfnembedded]

@@artfulbytes Oh sorry I mean your editor. By the way many thanks!

[@pedro_alonso]

Nice video! Can you share which font are you using in the terminal?

[@artfulbytes]

Yes, iosevka nerd font mono github.com/niklasab/dotfiles/blob/main/.fonts/iosevka-term-nerd-font-complete-mono.ttf

[@devrim-oguz]

esp-idf has printf built-in. As well as Arduino's Serial.printf()

[@artfulbytes]

Is there anything they don't have "inbuilt"? 😉 They give you an entire software stack for better worse. And if we are talking esp32 that plays in an entirely different league 🙂

[@kesmik]

The escape sequence is really strange :) Is it correct or you wanted to implement oposite? Asking because never heard of that, but looks strange if printf will be somehing like printf("hi "); it will become "hi " P.S. seems added comment under wrong video, ment to be on previous.. (did not watched this yet).

[@artfulbytes]

Damn it, you are right! I got it mixed up. Thanks, will fix it in future video 😅

[@olivialinden8699]

The left eye is black

[@artfulbytes]

AR!🏴‍☠

[@walidoulondon8107]

Hello are you Italian?

[@artfulbytes]

No, I'm from Sweden :)

[@user-zp9cn8mu3d]

What use of static void,()?

[@artfulbytes]

"Local" function with no return value. In other words, it's a function that is only accessible in the .c file where it's defined and it doesn't return anything.

[@user-zp9cn8mu3d]

If static function is .h library it can access in any library .c .if I include

[@artfulbytes]

@@user-zp9cn8mu3d Yes it's possible to define a static function in a header file and then include that header file in other c files. Not sure why you would do that though, apart from some very rare use-case.

[@user-zp9cn8mu3d]

Now I understand use of static keyword but I didn't know where I use static variable and static function?

[@user-zp9cn8mu3d]

Most of the functions in .h file written in static function example:static void toggle_Gpio that 's I confusing .