windows_receiver.c

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

/* baudrate settings are defined in <asm/termbits.h>, which is
included by <termios.h> */
#define BAUDRATE B38400      
#define VSWTC 7      
/* change this definition for the correct port */
#define _POSIX_SOURCE 1 /* POSIX compliant source */

#define FALSE 0
#define TRUE 1

volatile int STOP = FALSE; 

int main
(int argc, char **argv)
{
    int fd, res;
    struct termios oldtio, newtio;
    printf("Connecting to port %s...\n",argv[1]);
    uint8_t *buf = calloc(20 * sizeof(uint8_t), 0);
    char *MODEMDEVICE = argv[1];
  /* 
    Open modem device for reading and writing and not as controlling tty
    because we don't want to get killed if linenoise sends CTRL-C.
  */
   fd = open(MODEMDEVICE, O_RDONLY | O_NOCTTY | O_NONBLOCK);//, O_RDWR | O_NOCTTY);

   if (fd < 0) {
      perror(MODEMDEVICE); 
      exit(-1); 
    }

   fcntl(fd, F_SETFL, 0);
   tcgetattr(fd, &oldtio); /* save current serial port settings */
   bzero(&newtio, sizeof(newtio)); /* clear struct for new port settings */

  /* 
    BAUDRATE: Set bps rate. You could also use cfsetispeed and cfsetospeed.
    CRTSCTS : output hardware flow control (only used if the cable has
              all necessary lines. See sect. 7 of Serial-HOWTO)
    CS8     : 8n1 (8bit,no parity,1 stopbit)
    CLOCAL  : local connection, no modem contol
    CREAD   : enable receiving characters
  */
   newtio.c_cflag |= BAUDRATE | CRTSCTS | CS8 | CLOCAL | CREAD;
   newtio.c_cflag &= ~(PARENB | CSTOPB | CSIZE);
  /*
    IGNPAR  : ignore bytes with parity errors
    ICRNL   : map CR to NL (otherwise a CR input on the other computer
              will not terminate input)
    otherwise make device raw (no other input processing)
  */
   newtio.c_iflag = IGNPAR | ICRNL;
  
  /*
   Raw output.
  */
   newtio.c_oflag = 1;
   
  /*
    ICANON  : enable canonical input
    disable all echo functionality, and don't send signals to calling program
  */
   newtio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
   
  /* 
    initialize all control characters 
    default values can be found in /usr/include/termios.h, and are given
    in the comments, but we don't need them here
  */
   newtio.c_cc[VINTR]    = 0;     /* Ctrl-c */ 
   newtio.c_cc[VQUIT]    = 0;     /* Ctrl-\ */
   newtio.c_cc[VERASE]   = 0;     /* del */
   newtio.c_cc[VKILL]    = 0;     /* @ */
   newtio.c_cc[VEOF]     = 4;     /* Ctrl-d */
   newtio.c_cc[VTIME]    = 0;     /* inter-character timer unused */
   newtio.c_cc[VMIN]     = 20;     /* blocking read until 20 character arrives */
   newtio.c_cc[VSWTC]    = 0;     /* '\0' */
   newtio.c_cc[VSTART]   = 0;     /* Ctrl-q */ 
   newtio.c_cc[VSTOP]    = 0;     /* Ctrl-s */
   newtio.c_cc[VSUSP]    = 0;     /* Ctrl-z */
   newtio.c_cc[VEOL]     = 0;     /* '\0' */
   newtio.c_cc[VREPRINT] = 0;     /* Ctrl-r */
   newtio.c_cc[VDISCARD] = 0;     /* Ctrl-u */
   newtio.c_cc[VWERASE]  = 0;     /* Ctrl-w */
   newtio.c_cc[VLNEXT]   = 0;     /* Ctrl-v */
   newtio.c_cc[VEOL2]    = 0;     /* '\0' */

  /* 
    now clean the modem line and activate the settings for the port
  */
   tcflush(fd, TCIFLUSH);
   tcsetattr(fd, TCSANOW, &newtio);
   printf("Finished Initialization...\n");
   
  /*
    terminal settings done, now handle input
    In this example, inputting a 'z' at the beginning of a line will 
    exit the program.
  */

   while (STOP == FALSE) {     /* loop until we have a terminating condition */
     /* read blocks program execution until a line terminating character is 
        input, even if more than 255 chars are input. If the number
        of characters read is smaller than the number of chars available,
        subsequent reads will return the remaining chars. res will be set
        to the actual number of characters actually read */

        res = read(fd, buf, 20);
        printf("%d\n", res); 
        for (int i = 0; i < 20; ++i) {
          printf("%hhu ", buf[i]);  
        }
        printf("END\n");   
   }
   /* restore the old port settings */
   tcsetattr(fd, TCSANOW, &oldtio);
   free(buf);
   return 0;
}