http://bbs.csdn.net/topics/340184140
/************************************************************************************ * tty_open_port() open the tty port
************************************************************************************/
int tty_open_port(const char *dev_name)
{ int fd; /* File descriptor for the port */
fd = open(dev_name, O_RDWR | O_NOCTTY | O_NDELAY);
if (-1 == fd)
{
perror("open_port: Unable to open tty " );
exit(1);
}
else
{
if(DEBUG)
printf("The %s is opened \n",dev_name);
}
/* if( (val=fcntl(fd, F_SETFL, 0))< 0)
perror("fcntl failed");
*/ if ( isatty(fd) == 0 )
perror("This is not a tty device ");
return (fd);
}/************************************************************************************ * tty_set_port() set the attributes of the tty
************************************************************************************/
int tty_set_port (int fd , int nSpeed , int nBits , char nEvent , int nStop )
{ struct termios new_ios,old_ios;
if ( tcgetattr ( fd , &new_ios ) !=0 )
perror("Save the terminal error");
bzero( &old_ios , sizeof( struct termios ));
old_ios=new_ios;
tcflush(fd,TCIOFLUSH) ;
new_ios.c_cflag |= CLOCAL |CREAD ;
new_ios.c_cflag &= ~CSIZE ;
switch (nBits)
{
case 5:
new_ios.c_cflag |=CS5 ;
break ;
case 6:
new_ios.c_cflag |=CS6 ;
break ;
case 7:
new_ios.c_cflag |=CS7 ;
break ;
case 8:
new_ios.c_cflag |=CS8 ;
break ;
default:
perror("Wrong nBits");
break ;
}
switch (nSpeed )
{
case 2400:
cfsetispeed(&new_ios , B2400);
cfsetospeed(&new_ios , B2400);
break;
case 4800:
cfsetispeed(&new_ios , B4800);
cfsetospeed(&new_ios , B4800);
break;
case 9600:
cfsetispeed(&new_ios , B9600);
cfsetospeed(&new_ios , B9600);
break;
case 19200:
cfsetispeed(&new_ios , B19200);
cfsetospeed(&new_ios , B19200);
break;
case 115200:
cfsetispeed(&new_ios , B115200);
cfsetospeed(&new_ios , B115200);
break;
case 460800:
cfsetispeed(&new_ios , B460800);
cfsetospeed(&new_ios , B460800);
break;
default:
perror("Wrong nSpeed");
break;
}
switch (nEvent )
{
case 'o':
case 'O':
new_ios.c_cflag |= PARENB ;
new_ios.c_cflag |= PARODD ;
new_ios.c_iflag |= (INPCK | ISTRIP);
break ;
case 'e':
case 'E':
new_ios.c_iflag |= (INPCK | ISTRIP);
new_ios.c_cflag |= PARENB ;
new_ios.c_cflag &= ~PARODD ;
break ;
case 'n':
case 'N':
new_ios.c_cflag &= ~PARENB ;
new_ios.c_iflag &= ~INPCK ;
break ;
default:
perror("Wrong nEvent");
break ;
}
if ( nStop == 1 )
new_ios.c_cflag &= ~CSTOPB ;
else if ( nStop == 2 )
new_ios.c_cflag |= CSTOPB ;
/*No hardware control*/
new_ios.c_cflag &= ~CRTSCTS;
/*No software control*/
new_ios.c_iflag &= ~(IXON | IXOFF | IXANY);
/*delay time set */
new_ios.c_cc[VTIME] = 0 ;
new_ios.c_cc[VMIN] = 0 ;
/*raw model*/
new_ios.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
new_ios.c_oflag &= ~OPOST;
new_ios.c_iflag &= ~(INLCR|IGNCR|ICRNL);
new_ios.c_iflag &= ~(ONLCR|OCRNL);
new_ios.c_oflag &= ~(INLCR|IGNCR|ICRNL);
new_ios.c_oflag &= ~(ONLCR|OCRNL);
tcflush(fd,TCIOFLUSH) ;
if (tcsetattr(fd,TCSANOW,&new_ios) != 0 )
{
perror("Set the terminal error");
tcsetattr(fd,TCSANOW,&old_ios);
return -1 ;
}
return 0;
}