Programming

//
// Skriv och las fran com-port
//
// Av: David Miller
//
// Andringshistorik:
// 
// Datum	Sign	Kommentar
// ----------------------------------------------------
// 12-05-21	DM	Grundversion

#include <stdio.h>   /* Standard input/output definitions */
#include <string.h>  /* String function definitions */
#include <unistd.h>  /* UNIX standard function definitions */
#include <fcntl.h>   /* File control definitions */
#include <errno.h>   /* Error number definitions */
#include <termios.h> /* POSIX terminal control definitions */
#include <time.h>

main()
{
	int fd;
	struct	termios options;
	char	b[255];  	// Input buffer
	char	*bufptr;      // Current char in buffer
	int		nbytes;       // Number of bytes read
	int		tries;        // Number of tries so far
	int		x;
	
	// open the port
    fd = open("/dev/ttyS0",O_RDWR | O_NOCTTY | O_NDELAY );
    fcntl(fd, F_SETFL, 0);

	
	
	// get the current options
	tcgetattr(fd, &options);
	tcsetattr(fd, TCSAFLUSH, &options); // activate the set options
	cfsetispeed(&options, B9600); // 9600 baud input
	cfsetospeed(&options, B9600); // 9600 baud output
	options.c_cflag |= (CLOCAL | CREAD); // enable receiver, local mode
	options.c_lflag &= ~( ICANON | ECHO | ECHOE | ISIG | IEXTEN ); // ensure raw input
	options.c_oflag &= ~OPOST; // ensure raw output

	// set the options
	tcsetattr(fd, TCSANOW, &options);

	printf("\nOpen: %d", fd);


	x = write(fd, "ATI\t", 4);

	printf("\nWrite: %d", x);

	sleep(1);

	x = 0;
	
	x = read(fd, b, 30);

	printf("\nRead: %s", b);
	close(fd);

}