identifier "DDRB" is undefined - VS code / Visual studio

Question

I am getting the following error when using the identifier DDRB:

identifier "DDRB" is undefined

But, when I click “go to definition”, the IDE does shows that it can find them. The code also compiles without any problem. I was using VScode first and setting intellisense to "tag parser" did work, but it also got rid of the error checking. So, I switched over to Visual Studio, but the issue remains. In both cases I included the AVR library.

I have googled quite a bit and found some solutions, but most were outdated or did not work. What can I do to resolve this issue?

"minimal reproducible example:"

#include <avr\io.h>

int main() {

    DDRB |= (1 << DD3);

}

Please provide [mre]. – Algirdas Preidžius Nov 19 '19 at 18:48 — Algirdas Preidžius, Nov 19 '19 at 18:48
Try adding `#define __AVR_ATmega32U4__` at the top. – LoLance Nov 20 '19 at 06:55 — LoLance, Nov 20 '19 at 06:55

score 3 · Accepted Answer · answered Nov 20 '19 at 08:16

I can reproduce same issue in VS2017, and this one can be resolved by adding the #define __AVR_ATmega32U4__ above the #include <avr\io.h> like this:

#define __AVR_ATmega32U4__ 
#include <iostream>
#include <avr/io.h>
int main()
{
    DDRB |= (1 << DD3);
}

After adding the macro definition, VS Intellisense option can recognize them well and the issue goes away. More details refer to Kissiel's reply. Thanks to him!

score 3 · Answer 2 · answered Nov 07 '21 at 08:03

3

If you don't want to paste this definition into almost every file:

press f1
find C/C++; Edit configurations (UI)
paste your mcu name in Defines section e.g __AVR_ATmega32U4__

It worked for me in vs code.

answered Nov 07 '21 at 08:03

gicher

61
4

**+ِ1**! Can't understand why it's not included by default. Very useful! – David Refoua Jan 30 '22 at 21:31

identifier "DDRB" is undefined - VS code / Visual studio

2 Answers2