int speed_arr[] = { B38400, B19200, B9600, B4800, B2400, B1200, B300,
B38400, B19200, B9600, B4800, B2400, B1200, B300,};
int name_arr[] = {38400, 19200, 9600, 4800, 2400, 1200, 300, 38400,
19200, 9600, 4800, 2400, 1200, 300,};
/**
*@brief Set Serial Port BitRate
*@param fd Type : int The File Description of Serial Port
*@param speed Type : int Serial Speed
*@return void
*/
void set_speed(int fd, int speed)
{
int i;
int status;
struct termios Opt;
tcgetattr(fd, &Opt);
for( i=0; i < (sizeof(speed_arr) / sizeof(int)); i++ )
{
if (speed == name_arr[i])
{
tcflush(fd, TCIOFLUSH);
cfsetispeed(&Opt, speed_arr[i]);
cfsetospeed(&Opt, speed_arr[i]);
status = tcsetattr(fd, TCSANOW, &Opt);
if (status != 0)
{
perror("tcsetattr fd");
return;
}
tcflush(fd,TCIOFLUSH);
}
}
}
/**
*@brief Set Serial Port Databits, Stopbits and Parity.
*@param fd Type: int The File Description of Serial Port
*@param databits Type: int Databits 7 or 8
*@param stopbits Type: int Stopbits 1 or 2
*@param parity Type: int Parity Type: n,N,e,E,o,O,s,S
*/
int set_Parity(int fd,int databits,int stopbits,int parity)
{
struct termios options;
if ( tcgetattr( fd,&options) != 0)
{
perror("SetupSerial 1");
return(-1);
}
options.c_cflag &= ~CSIZE;
switch (databits) /*Set Datebits*/
{
case 7:
options.c_cflag |= CS7;
break;
case 8:
options.c_cflag |= CS8;
break;
default:
fprintf(stderr,"Unsupported data size\n");
return(-1);
}
switch (parity) /*Set Parity*/
{
case 'n':
case 'N':
options.c_cflag &= ~PARENB; /* Clear parity enable */
options.c_iflag &= ~INPCK; /* Enable parity checking */
break;
case 'o':
case 'O':
options.c_cflag |= (PARODD | PARENB); /* Odd Checking*/
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'e':
case 'E':
options.c_cflag |= PARENB; /* Enable parity */
options.c_cflag &= ~PARODD; /* Even Checking*/
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'S':
case 's': /*as no parity*/
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;
break;
default:
fprintf(stderr,"Unsupported parity\n");
return(-1);
}
switch (stopbits) /*Set Stobits*/
{
case 1:
options.c_cflag &= ~CSTOPB;
break;
case 2:
options.c_cflag |= CSTOPB;
break;
default:
fprintf(stderr,"Unsupported stop bits\n");
return(-1);
}
/* Set input parity option */
if (parity != 'n')
options.c_iflag |= INPCK;
/*以下两句添加后发送方可以不加回车换行，但是read读取不完整*/
options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); /*Input*/
options.c_oflag &= ~OPOST; /*Output*/
tcflush(fd,TCIFLUSH);
options.c_cc[VTIME] = 150; /* Timeout in 15 seconds*/
options.c_cc[VMIN] = 0; /* Update the options and do it NOW */
if (tcsetattr(fd,TCSANOW,&options) != 0)
{
perror("SetupSerial 3");
return(-1);
}
return(0);
}
int main (int argc, char *argv[])
{
char buffer[512]="";
int ser_fd = open("/dev/ttyS1",O_RDWR | O_NOCTTY);
if ( -1 == ser_fd)
{
perror("Cannot Open Serial Port");
return(-1);
}
set_speed(ser_fd,19200);
if ( -1 == set_Parity(ser_fd,7,1,'E') )
{
printf("Set Parity Error\n");
close(ser_fd);
exit (-1);
}
while( 1 )
{
nread = read( ser_fd, buffer, sizeof(buffer));
if ( nread < 0 )
perror("read from Serial Port Error:\n");
}
}
