[Arduino] Serial Communication Linux

no-reply@allegro.cc (Ariesnl) — Mon, 03 Oct 2022 15:15:33 +0000

Hey everyone,
I started to play with Arduino (UNU)
I wanted to setup some test for sewrial communication with my pc.
I wrote a small and simple program to send some characters. the Arduino side seems to work fine, The serial monitor of the IDE shows the text the Arduino is sending, and also the test appears in "Screen" ( Linux minitoring program.
However trying to connect with my C++ program using LibSerial fails every time...

Any Ideas ?

Thanks !

#SelectExpand
  1#include 
  2#include 
  3
  4using namespace LibSerial;
  5
  6SerialStream g_StreamSerial;
  7
  8bool g_blClose = false;
  9
 10int main()
 11{
 12    g_StreamSerial.Open("/dev/ttyACMO");
 13    if (g_StreamSerial.good())
 14    {
 15        g_StreamSerial.SetBaudRate(BaudRate::BAUD_9600);
 16        if (g_StreamSerial.good())
 17        {
 18            char ch;
 19
 20            while(!g_blClose)
 21            {
 22
 23                g_StreamSerial >> ch;
 24                std::cout << ch;
 25            }
 26        }
 27        else
 28        {
 29            std::cout << "Could not set baud rate";
 30        }
 31
 32
 33    }
 34    else
 35    {
 36        std::cout << "Could not open port";
 37    }
 38
 39    g_StreamSerial.Close();
 40    return 0;
 41}

no-reply@allegro.cc (Dizzy Egg) — Mon, 03 Oct 2022 20:40:06 +0000

Are you running it with sudo priveliges?

no-reply@allegro.cc (Ariesnl) — Tue, 04 Oct 2022 12:24:57 +0000

No, but would that be necessary ?
Would be inconvenient to use sudo every time running this...

no-reply@allegro.cc (Peter Hull) — Tue, 04 Oct 2022 17:26:05 +0000

Maybe try .IsOpen() instead of .good() and see if an error message becomes apparent?

edit - also are you opening "/dev/ttyACMO" with a letter "O" or "/dev/ttyACM0" with a zero? I think the latter is correct.

no-reply@allegro.cc (Ariesnl) — Wed, 05 Oct 2022 16:18:20 +0000

Makes no difference, and yes the last char is a zero ;-)

no-reply@allegro.cc (Peter Hull) — Wed, 05 Oct 2022 20:24:09 +0000

Ariesnl said:

yes the last char is a zero

OK because it isn't in the code you posted.

How do you know the error is "Bad file descriptor"? (EBADF presumably?)

If you try to just open() that file does it work?

no-reply@allegro.cc (Dizzy Egg) — Wed, 05 Oct 2022 21:58:55 +0000

Have you given yourself permission to acces the ports?

i.e.

sudo usermod -a -G dialout
sudo usermod -a -G plugdev

no-reply@allegro.cc (Peter Hull) — Thu, 06 Oct 2022 01:04:08 +0000

Surely if it works from screen and from the Arduino IDE, the permissions are OK?