Init, read and write for a serial linux device with C

Question

I am working on a new project where I want to establish a connection with FTDI, which is connected to my debian machine. I intend to write code with C, not C ++. Here lies my problem. All the examples that I find are incomplete or made for the C ++ compiler instead of the GCC compiler.

The goal is to talk to my microcontroller that is connected to FTDI. For debugging, I want to start creating a linux application that can:

• initialize serial connection at startup using ttyUSB1
• send character string
• display character strings when they are received by the computer
• save message in .txt file

Is there any code sample or tutorial to do this?

If I succeed, I will definitely install the code here so that new viewers can use it!

Edit:

As I said, I would post the code if I had it, and this is what worked for me:

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>

#define MODEM "/dev/ttyUSB0"
#define BAUDRATE B115200    

int main(int argc,char** argv)
{   
    struct termios tio;
    struct termios stdio;
    struct termios old_stdio;
    int tty_fd, flags;
    unsigned char c='D';
    tcgetattr(STDOUT_FILENO,&old_stdio);
    printf("Please start with %s /dev/ttyS1 (for example)\n",argv[0]);
    memset(&stdio,0,sizeof(stdio));
    stdio.c_iflag=0;
    stdio.c_oflag=0;
    stdio.c_cflag=0;
    stdio.c_lflag=0;
    stdio.c_cc[VMIN]=1;
    stdio.c_cc[VTIME]=0;
    tcsetattr(STDOUT_FILENO,TCSANOW,&stdio);
    tcsetattr(STDOUT_FILENO,TCSAFLUSH,&stdio);
    fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);       // make the reads non-blocking
    memset(&tio,0,sizeof(tio));
    tio.c_iflag=0;
    tio.c_oflag=0;
    tio.c_cflag=CS8|CREAD|CLOCAL;           // 8n1, see termios.h for more information
    tio.c_lflag=0;
    tio.c_cc[VMIN]=1;
    tio.c_cc[VTIME]=5;
    if((tty_fd = open(MODEM , O_RDWR | O_NONBLOCK)) == -1){
        printf("Error while opening\n"); // Just if you want user interface error control
        return -1;
    }
    cfsetospeed(&tio,BAUDRATE);    
    cfsetispeed(&tio,BAUDRATE);            // baudrate is declarated above
    tcsetattr(tty_fd,TCSANOW,&tio);
    while (c!='q'){
        if (read(tty_fd,&c,1)>0){
            write(STDOUT_FILENO,&c,1); // if new data is available on the serial port, print it out
            printf("\n");
        }
        if (read(STDIN_FILENO,&c,1)>0){
            write(tty_fd,&c,1);//if new data is available on the console, send it to serial port
            printf("\n");
        }
    }
    close(tty_fd);
    tcsetattr(STDOUT_FILENO,TCSANOW,&old_stdio);
    return EXIT_SUCCESS;
}

Most of the code comes from http://en.wikibooks.org/wiki/Serial_Programming/Serial_Linux , but I also used the code below a bit.

Answer 1

( Linux-):
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int fd; // file descriptor
int flags; // communication flags
int rsl_len; // result size
char message; // message to send
char result; // result to read

flags = O_RDWR | O_NOCTTY; // Read and write, and make the job control for portability
if ((fd = open("/dev/ttyUSB1", flags)) == -1 ) {
  printf("Error while opening\n"); // Just if you want user interface error control
  return -1;
}
// In this point your communication is already estabilished, lets send out something
strcpy(message, "Hello");
if (rsl_len = write(fd, message, strlen(message)) < 0 ) {
  printf("Error while sending message\n"); // Again just in case
  return -2;
}
if (rsl_len = read(fd, &result, sizeof(result)) < 0 ) {
  printf("Error while reading return\n");
  return -3;
}
close(fd);

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Answer 2

gcc C/++, C.

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++, , ​​ Qt. Qt 5 QtSerialPort, , , Qt gui, /.

QtSerialPort Qt 4, Qt 4, . Qt 5, ++ 11.

Qt , , . Qt Qt 5 ++ 11. core serialport. SIGINT, - ^C. QLocalSocket raw Unix API Unix, .

main, - , ^C.

#include <QCoreApplication>
#include <QSerialPort>
#include <QFile>
#include <QTextStream>
#include <QLocalServer>
#include <QLocalSocket>
#include <cstdio>
#include <csignal>

QLocalSocket * xmit;

static void signalHandler(int)
{
    xmit->write(" ");
    xmit->flush();
}

static bool setupSignalHandler()
{
    QLocalServer srv;
    srv.listen("foobarbaz");
    xmit = new QLocalSocket(qApp);
    xmit->connectToServer(srv.serverName(), QIODevice::WriteOnly);
    srv.waitForNewConnection();
    QLocalSocket * receive = srv.nextPendingConnection();
    receive->setParent(qApp);
    qApp->connect(receive, &QLocalSocket::readyRead, &QCoreApplication::quit);
    struct sigaction sig;
    sig.sa_handler = signalHandler;
    sigemptyset(&sig.sa_mask);
    sig.sa_flags = SA_RESTART;
    return ! sigaction(SIGINT, &sig, NULL);
}

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    setupSignalHandler();

    QSerialPort port("ttyUSB1");
    QFile file("file.txt");
    QTextStream err(stderr, QIODevice::WriteOnly);
    QTextStream out(stdout, QIODevice::WriteOnly);
    if (!file.open(QIODevice::WriteOnly)) {
        err << "Couldn't open the output file" << endl;
        return 1;
    }
    if (!port.open(QIODevice::ReadWrite)) {
        err << "Couldn't open the port" << endl;
        return 2;
    }
    port.setBaudRate(9600);
    QObject::connect(&port, &QSerialPort::readyRead, [&](){
        QByteArray data = port.readAll();
        out << data;
        file.write(data);
    });
    out << "Use ^C to quit" << endl;
    return a.exec();
}