linux_serial.cpp

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#include "serial.h"  /* Std. function protos */
#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 <stdlib.h>  /* Malloc */


int OpenSerial(int* fd, const char* port_name)
{
        *fd = open(port_name, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK);
        if (*fd == -1) {
                fprintf(stderr, "Unable to open %s\n\r", port_name);
                return -3;
        } 

    // Verify it is a serial port
    if (!isatty(*fd)) {
        close(*fd);
            fprintf(stderr, "%s is not a serial port\n", port_name);
        return -3;
    }

        return *fd;
}

int SetupSerial(int fd, int baudrate)
{
    struct termios options;

    // Get the current options for the port...
    tcgetattr(fd, &options);

    // 8 bits, 1 stop, no parity
    options.c_cflag = 0;
    options.c_cflag |= CS8;         // 8-bit input

    // Enable the receiver and set local mode...
    options.c_cflag |= (CLOCAL | CREAD);

    /* Set baud rate (default is 115200.
     * There isn't a clear mapping from the integral baud rate
     * to the termios speed_t.  Cases will need to be added
     * for each baud we want to support. */
    if( (baudrate == 0) || (baudrate==115200) ) {
        cfsetispeed(&options, B115200);
        cfsetospeed(&options, B115200);
    } else if( (baudrate==57600) ) {
        cfsetispeed(&options, B57600);
        cfsetospeed(&options, B57600);
    } else if( (baudrate==38400) ) {
        cfsetispeed(&options, B38400);
        cfsetospeed(&options, B38400);
    } else if( (baudrate==19200) ) {
        cfsetispeed(&options, B19200);
        cfsetospeed(&options, B19200);
    } else if( (baudrate==9600) ) {
        cfsetispeed(&options, B9600);
        cfsetospeed(&options, B9600);
    } else {
        // Requested baud not supported
        return -1;
    }

    // No input processing
    options.c_iflag = 0;

    // No output processing
    options.c_oflag = 0;

    // No line processing
    options.c_lflag = 0;

    // read timeout
    options.c_cc[VMIN]  = 0;    // non-blocking
    options.c_cc[VTIME] = 1;    // always return after 0.1 seconds

    // Set the new options for the port...
    tcsetattr(fd, TCSAFLUSH, &options);

    return 0;
}