// note that this only supports baud rates defined in termios.
int serial_connect(const char* portpath, int flags, speed_t baudrate)
{
speed_t new_baudrate;
struct termios port_attrib; // termios attributes struct
int fport = open(portpath,flags);
if (fport == -1)
{
printf("Unable to open %s.\n", portpath);
printf("Check that the device is plugged in and turned on.\n");
return -1;
}
// get the current port settings
if (tcgetattr(fport, &port_attrib) < 0)
{
printf(" Failed to get port settings.\n");
close(fport);
return -1;
}
// set raw mode
cfmakeraw(&port_attrib);
// set the baud rate to baudrate
if (cfsetspeed(&port_attrib,baudrate) < 0)
{ printf(" Invalid baud rate specified or other baud rate error.\n");
close(fport);
return -1;}
// clear the serial line
tcflush(fport, TCIOFLUSH);
// apply the port settings (baud rate and raw mode)
if (tcsetattr(fport,TCSANOW,&port_attrib) < 0)
{
printf(" Failed to apply new port settings.\n");
close(fport);
return -1;
}
// try to get the new port settings
if (tcgetattr(fport, &port_attrib) < 0)
{
printf(" Failed to get port settings.\n");
close(fport);
return -1;
}
// print the new baud rate
new_baudrate = cfgetospeed(&port_attrib);
if (new_baudrate == baudrate)
printf(" Port opened at baud rate: %d.\n",convert_baudrate(baudrate));
else
{
printf("Couldn't set baud rate.\n");
close(fport);
return -1;
}
return fport;
}
int COM_Setup(int fd, COM_PARAM param)
{
int ret = -1;
struct termios termios_old;
struct termios termios_new;
int baudrate = 0;
int fctl = 0;
int databit = 0;
int stopbit = 0;
int parity = 0;
if (fd < 0)
{
return -1;
}
bzero(&termios_old, sizeof(termios_old));
bzero(&termios_new, sizeof(termios_new));
cfmakeraw(&termios_new);
tcgetattr(fd, &termios_old);
// baudrates
baudrate = convert_baudrate(param.nBaudRate);
cfsetispeed(&termios_new, baudrate);
cfsetospeed(&termios_new, baudrate);
termios_new.c_cflag |= CLOCAL;
termios_new.c_cflag |= CREAD;
fctl = param.nFlowCtrl;
switch (fctl)
{
case '0':
termios_new.c_cflag &= ~CRTSCTS; // no flow control
break;
case '1':
termios_new.c_cflag |= CRTSCTS; // hardware flow control
break;
case '2':
termios_new.c_iflag |= IXON | IXOFF |IXANY; //software flow control
break;
}
// data bits
termios_new.c_cflag &= ~CSIZE;
databit = param.nDataBits;
switch (databit)
{
case '5':
termios_new.c_cflag |= CS5;
break;
case '6':
termios_new.c_cflag |= CS6;
break;
case '7':
termios_new.c_cflag |= CS7;
break;
default:
termios_new.c_cflag |= CS8;
break;
}
// parity check
parity = param.nParity;
switch (parity)
{
case '0':
termios_new.c_cflag &= ~PARENB; // no parity check
break;
case '1':
termios_new.c_cflag |= PARENB; // odd check
termios_new.c_cflag &= ~PARODD;
break;
case '2':
termios_new.c_cflag |= PARENB; // even check
termios_new.c_cflag |= PARODD;
break;
}
// stop bits
stopbit = param.nStopBits;
if (stopbit == '2')
{
termios_new.c_cflag |= CSTOPB; // 2 stop bits
}
else
{
termios_new.c_cflag &= ~CSTOPB; // 1 stop bits
}
//other attributions default
termios_new.c_oflag &= ~OPOST;
termios_new.c_cc[VMIN] = 1;
termios_new.c_cc[VTIME] = 1; // unit: (1/10)second
tcflush(fd, TCIFLUSH);
ret = tcsetattr(fd, TCSANOW, &termios_new); // TCSANOW
tcgetattr(fd, &termios_old);
return ret;
}
