rs232.cpp

/*
***************************************************************************
*
* Author: Teunis van Beelen
*
* Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 Teunis van Beelen
*
* Email: teuniz@gmail.com
*
***************************************************************************
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
***************************************************************************
*
* This version of GPL is at http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
*
***************************************************************************
*/

/* Last revision: October 10, 2015 */

/* For more info and how to use this library, visit: http://www.teuniz.net/RS-232/ */


#include "rs232.h"
#include <stdio.h>



#if defined(__linux__) || defined(__FreeBSD__)   /* Linux & FreeBSD */


int Cport[38],
error;

struct termios new_port_settings,
	old_port_settings[38];

char comports[38][16]={"/dev/ttyS0","/dev/ttyS1","/dev/ttyS2","/dev/ttyS3","/dev/ttyS4","/dev/ttyS5",
"/dev/ttyS6","/dev/ttyS7","/dev/ttyS8","/dev/ttyS9","/dev/ttyS10","/dev/ttyS11",
"/dev/ttyS12","/dev/ttyS13","/dev/ttyS14","/dev/ttyS15","/dev/ttyUSB0",
"/dev/ttyUSB1","/dev/ttyUSB2","/dev/ttyUSB3","/dev/ttyUSB4","/dev/ttyUSB5",
"/dev/ttyAMA0","/dev/ttyAMA1","/dev/ttyACM0","/dev/ttyACM1",
"/dev/rfcomm0","/dev/rfcomm1","/dev/ircomm0","/dev/ircomm1",
"/dev/cuau0","/dev/cuau1","/dev/cuau2","/dev/cuau3",
"/dev/cuaU0","/dev/cuaU1","/dev/cuaU2","/dev/cuaU3"};

int RS232_OpenComport(int comport_number, int baudrate, const char *mode)
{
	int baudr,
		status;

	if((comport_number>37)||(comport_number<0))
	{
		printf("illegal comport number\n");
		return(1);
	}

	switch(baudrate)
	{
	case      50 : baudr = B50;
		break;
	case      75 : baudr = B75;
		break;
	case     110 : baudr = B110;
		break;
	case     134 : baudr = B134;
		break;
	case     150 : baudr = B150;
		break;
	case     200 : baudr = B200;
		break;
	case     300 : baudr = B300;
		break;
	case     600 : baudr = B600;
		break;
	case    1200 : baudr = B1200;
		break;
	case    1800 : baudr = B1800;
		break;
	case    2400 : baudr = B2400;
		break;
	case    4800 : baudr = B4800;
		break;
	case    9600 : baudr = B9600;
		break;
	case   19200 : baudr = B19200;
		break;
	case   38400 : baudr = B38400;
		break;
	case   57600 : baudr = B57600;
		break;
	case  115200 : baudr = B115200;
		break;
	case  230400 : baudr = B230400;
		break;
	case  460800 : baudr = B460800;
		break;
	case  500000 : baudr = B500000;
		break;
	case  576000 : baudr = B576000;
		break;
	case  921600 : baudr = B921600;
		break;
	case 1000000 : baudr = B1000000;
		break;
	case 1152000 : baudr = B1152000;
		break;
	case 1500000 : baudr = B1500000;
		break;
	case 2000000 : baudr = B2000000;
		break;
	case 2500000 : baudr = B2500000;
		break;
	case 3000000 : baudr = B3000000;
		break;
	case 3500000 : baudr = B3500000;
		break;
	case 4000000 : baudr = B4000000;
		break;
	default      : printf("invalid baudrate\n");
		return(1);
		break;
	}

	int cbits=CS8,
		cpar=0,
		ipar=IGNPAR,
		bstop=0;

	if(strlen(mode) != 3)
	{
		printf("invalid mode \"%s\"\n", mode);
		return(1);
	}

	switch(mode[0])
	{
	case '8': cbits = CS8;
		break;
	case '7': cbits = CS7;
		break;
	case '6': cbits = CS6;
		break;
	case '5': cbits = CS5;
		break;
	default : printf("invalid number of data-bits '%c'\n", mode[0]);
		return(1);
		break;
	}

	switch(mode[1])
	{
	case 'N':
	case 'n': cpar = 0;
		ipar = IGNPAR;
		break;
	case 'E':
	case 'e': cpar = PARENB;
		ipar = INPCK;
		break;
	case 'O':
	case 'o': cpar = (PARENB | PARODD);
		ipar = INPCK;
		break;
	default : printf("invalid parity '%c'\n", mode[1]);
		return(1);
		break;
	}

	switch(mode[2])
	{
	case '1': bstop = 0;
		break;
	case '2': bstop = CSTOPB;
		break;
	default : printf("invalid number of stop bits '%c'\n", mode[2]);
		return(1);
		break;
	}

	/*
	http://pubs.opengroup.org/onlinepubs/7908799/xsh/termios.h.html

	http://man7.org/linux/man-pages/man3/termios.3.html
	*/

	Cport[comport_number] = open(comports[comport_number], O_RDWR | O_NOCTTY | O_NDELAY);
	if(Cport[comport_number]==-1)
	{
		perror("unable to open comport ");
		return(1);
	}

	/* lock access so that another process can't also use the port */
	if(flock(Cport[comport_number], LOCK_EX | LOCK_NB) != 0)
	{
		close(Cport[comport_number]);
		perror("Another process has locked the comport.");
		return(1);
	}

	error = tcgetattr(Cport[comport_number], old_port_settings + comport_number);
	if(error==-1)
	{
		close(Cport[comport_number]);
		perror("unable to read portsettings ");
		return(1);
	}
	memset(&new_port_settings, 0, sizeof(new_port_settings));  /* clear the new struct */

	new_port_settings.c_cflag = cbits | cpar | bstop | CLOCAL | CREAD;
	new_port_settings.c_iflag = ipar;
	new_port_settings.c_oflag = 0;
	new_port_settings.c_lflag = 0;
	new_port_settings.c_cc[VMIN] = 0;      /* block untill n bytes are received */
	new_port_settings.c_cc[VTIME] = 0;     /* block untill a timer expires (n * 100 mSec.) */

	cfsetispeed(&new_port_settings, baudr);
	cfsetospeed(&new_port_settings, baudr);

	error = tcsetattr(Cport[comport_number], TCSANOW, &new_port_settings);
	if(error==-1)
	{
		close(Cport[comport_number]);
		perror("unable to adjust portsettings ");
		return(1);
	}

	if(ioctl(Cport[comport_number], TIOCMGET, &status) == -1)
	{
		perror("unable to get portstatus");
		return(1);
	}

	status |= TIOCM_DTR;    /* turn on DTR */
	status |= TIOCM_RTS;    /* turn on RTS */

	if(ioctl(Cport[comport_number], TIOCMSET, &status) == -1)
	{
		perror("unable to set portstatus");
		return(1);
	}

	return(0);
}


int RS232_PollComport(int comport_number, unsigned char *buf, int size)
{
	int n;

	n = read(Cport[comport_number], buf, size);

	return(n);
}


int RS232_SendByte(int comport_number, unsigned char byte)
{
	int n;

	n = write(Cport[comport_number], &byte, 1);
	if(n<0)  return(1);

	return(0);
}


int RS232_SendBuf(int comport_number, unsigned char *buf, int size)
{
	return(write(Cport[comport_number], buf, size));
}


void RS232_CloseComport(int comport_number)
{
	int status;

	if(ioctl(Cport[comport_number], TIOCMGET, &status) == -1)
	{
		perror("unable to get portstatus");
	}

	status &= ~TIOCM_DTR;    /* turn off DTR */
	status &= ~TIOCM_RTS;    /* turn off RTS */

	if(ioctl(Cport[comport_number], TIOCMSET, &status) == -1)
	{
		perror("unable to set portstatus");
	}

	tcsetattr(Cport[comport_number], TCSANOW, old_port_settings + comport_number);
	close(Cport[comport_number]);

	flock(Cport[comport_number], LOCK_UN); /* free the port so that others can use it. */
}

/*
Constant  Description
TIOCM_LE        DSR (data set ready/line enable)
TIOCM_DTR       DTR (data terminal ready)
TIOCM_RTS       RTS (request to send)
TIOCM_ST        Secondary TXD (transmit)
TIOCM_SR        Secondary RXD (receive)
TIOCM_CTS       CTS (clear to send)
TIOCM_CAR       DCD (data carrier detect)
TIOCM_CD        see TIOCM_CAR
TIOCM_RNG       RNG (ring)
TIOCM_RI        see TIOCM_RNG
TIOCM_DSR       DSR (data set ready)

http://man7.org/linux/man-pages/man4/tty_ioctl.4.html
*/

int RS232_IsDCDEnabled(int comport_number)
{
	int status;

	ioctl(Cport[comport_number], TIOCMGET, &status);

	if(status&TIOCM_CAR) return(1);
	else return(0);
}

int RS232_IsCTSEnabled(int comport_number)
{
	int status;

	ioctl(Cport[comport_number], TIOCMGET, &status);

	if(status&TIOCM_CTS) return(1);
	else return(0);
}

int RS232_IsDSREnabled(int comport_number)
{
	int status;

	ioctl(Cport[comport_number], TIOCMGET, &status);

	if(status&TIOCM_DSR) return(1);
	else return(0);
}

void RS232_enableDTR(int comport_number)
{
	int status;

	if(ioctl(Cport[comport_number], TIOCMGET, &status) == -1)
	{
		perror("unable to get portstatus");
	}

	status |= TIOCM_DTR;    /* turn on DTR */

	if(ioctl(Cport[comport_number], TIOCMSET, &status) == -1)
	{
		perror("unable to set portstatus");
	}
}

void RS232_disableDTR(int comport_number)
{
	int status;

	if(ioctl(Cport[comport_number], TIOCMGET, &status) == -1)
	{
		perror("unable to get portstatus");
	}

	status &= ~TIOCM_DTR;    /* turn off DTR */

	if(ioctl(Cport[comport_number], TIOCMSET, &status) == -1)
	{
		perror("unable to set portstatus");
	}
}

void RS232_enableRTS(int comport_number)
{
	int status;

	if(ioctl(Cport[comport_number], TIOCMGET, &status) == -1)
	{
		perror("unable to get portstatus");
	}

	status |= TIOCM_RTS;    /* turn on RTS */

	if(ioctl(Cport[comport_number], TIOCMSET, &status) == -1)
	{
		perror("unable to set portstatus");
	}
}

void RS232_disableRTS(int comport_number)
{
	int status;

	if(ioctl(Cport[comport_number], TIOCMGET, &status) == -1)
	{
		perror("unable to get portstatus");
	}

	status &= ~TIOCM_RTS;    /* turn off RTS */

	if(ioctl(Cport[comport_number], TIOCMSET, &status) == -1)
	{
		perror("unable to set portstatus");
	}
}


#else         /* windows */


HANDLE Cport[16];


char comports[16][10] = { "\\\\.\\COM1", "\\\\.\\COM2", "\\\\.\\COM3", "\\\\.\\COM4",
"\\\\.\\COM5", "\\\\.\\COM6", "\\\\.\\COM7", "\\\\.\\COM8",
"\\\\.\\COM9", "\\\\.\\COM10", "\\\\.\\COM11", "\\\\.\\COM12",
"\\\\.\\COM13", "\\\\.\\COM14", "\\\\.\\COM15", "\\\\.\\COM16" };

char mode_str[128];


int RS232_OpenComport(int comport_number, int baudrate, const char *mode)
{
	if ((comport_number > 15) || (comport_number < 0))
	{
		printf("illegal comport number\n");
		return(1);
	}

	switch (baudrate)
	{
		//case     110 : strcpy_s(mode_str, sizeof(mode_str),"baud=110");
		//               break;
		//case     300 : strcpy_s(mode_str, "baud=300");
		//               break;
		//case     600 : strcpy_s(mode_str, "baud=600");
		//               break;
		//case    1200 : strcpy_s(mode_str, "baud=1200");
		//               break;
		//case    2400 : strcpy(mode_str, "baud=2400");
		//               break;
		//case    4800 : strcpy(mode_str, "baud=4800");
		//               break;
		case    9600: strcpy_s(mode_str, sizeof(mode_str), "baud=9600");
						break;
		case   19200: strcpy_s(mode_str, sizeof(mode_str), "baud=19200");
		               break;
		//case   38400 : strcpy(mode_str, "baud=38400");
		//               break;
		//case   57600 : strcpy(mode_str, "baud=57600");
		//               break;
	case  115200: strcpy_s(mode_str, sizeof(mode_str), "baud=115200");
		break;
	case  128000: strcpy_s(mode_str, sizeof(mode_str), "baud=128000");
		break;
	case  256000: strcpy_s(mode_str, sizeof(mode_str), "baud=256000");
		break;
	case  500000: strcpy_s(mode_str, sizeof(mode_str), "baud=500000");
		break;
	case 1000000: strcpy_s(mode_str, sizeof(mode_str), "baud=1000000");
		break;
	case 230400: strcpy_s(mode_str, sizeof(mode_str), "baud=230400");
		break;
	default: printf("invalid baudrate\n");
		return(1);
		break;
	}

	if (strlen(mode) != 3)
	{
		printf("invalid mode \"%s\"\n", mode);
		return(1);
	}

	switch (mode[0])
	{
	case '8': strcat_s(mode_str, sizeof(mode_str), " data=8");
		break;
	case '7': strcat_s(mode_str, sizeof(mode_str), " data=7");
		break;
	case '6': strcat_s(mode_str, sizeof(mode_str), " data=6");
		break;
	case '5': strcat_s(mode_str, sizeof(mode_str), " data=5");
		break;
	default: printf("invalid number of data-bits '%c'\n", mode[0]);
		return(1);
		break;
	}

	switch (mode[1])
	{
	case 'N':
	case 'n': strcat_s(mode_str, sizeof(mode_str), " parity=n");
		break;
	case 'E':
	case 'e': strcat_s(mode_str, sizeof(mode_str), " parity=e");
		break;
	case 'O':
	case 'o': strcat_s(mode_str, sizeof(mode_str), " parity=o");
		break;
	default: printf("invalid parity '%c'\n", mode[1]);
		return(1);
		break;
	}

	switch (mode[2])
	{
	case '1': strcat_s(mode_str, sizeof(mode_str), " stop=1");
		break;
	case '2': strcat_s(mode_str, sizeof(mode_str), " stop=2");
		break;
	default: printf("invalid number of stop bits '%c'\n", mode[2]);
		return(1);
		break;
	}

	strcat_s(mode_str, sizeof(mode_str), " dtr=on rts=on");

	/*
	http://msdn.microsoft.com/en-us/library/windows/desktop/aa363145%28v=vs.85%29.aspx

	http://technet.microsoft.com/en-us/library/cc732236.aspx
	*/

	Cport[comport_number] = CreateFileA(comports[comport_number],
		GENERIC_READ | GENERIC_WRITE,
		0,                          /* no share  */
		NULL,                       /* no security */
		OPEN_EXISTING,
		0,                          /* no threads */
		NULL);                      /* no templates */

	if (Cport[comport_number] == INVALID_HANDLE_VALUE)
	{
		printf("unable to open comport\n");
		return(1);
	}

	DCB port_settings;
	memset(&port_settings, 0, sizeof(port_settings));  /* clear the new struct  */
	port_settings.DCBlength = sizeof(port_settings);

	if (!BuildCommDCBA(mode_str, &port_settings))
	{
		printf("unable to set comport dcb settings\n");
		CloseHandle(Cport[comport_number]);
		return(1);
	}

	if (!SetCommState(Cport[comport_number], &port_settings))
	{
		printf("unable to set comport cfg settings\n");
		CloseHandle(Cport[comport_number]);
		return(1);
	}

	COMMTIMEOUTS Cptimeouts;

	Cptimeouts.ReadIntervalTimeout = MAXDWORD;
	Cptimeouts.ReadTotalTimeoutMultiplier = 0;
	Cptimeouts.ReadTotalTimeoutConstant = 0;
	Cptimeouts.WriteTotalTimeoutMultiplier = 0;
	Cptimeouts.WriteTotalTimeoutConstant = 0;

	if (!SetCommTimeouts(Cport[comport_number], &Cptimeouts))
	{
		printf("unable to set comport time-out settings\n");
		CloseHandle(Cport[comport_number]);
		return(1);
	}

	return(0);
}


int RS232_PollComport(int comport_number, unsigned char *buf, int size)
{
	int n;

	/* added the void pointer cast, otherwise gcc will complain about */
	/* "warning: dereferencing type-punned pointer will break strict aliasing rules" */

	ReadFile(Cport[comport_number], buf, size, (LPDWORD)((void *)&n), NULL);

	return(n);
}


int RS232_SendByte(int comport_number, unsigned char byte)
{
	int n;

	WriteFile(Cport[comport_number], &byte, 1, (LPDWORD)((void *)&n), NULL);

	if (n < 0)  return(1);

	return(0);
}


int RS232_SendBuf(int comport_number, unsigned char *buf, int size)
{
	int n;

	if (WriteFile(Cport[comport_number], buf, size, (LPDWORD)((void *)&n), NULL))
	{
		return(n);
	}

	return(-1);
}


void RS232_CloseComport(int comport_number)
{
	CloseHandle(Cport[comport_number]);
}

/*
http://msdn.microsoft.com/en-us/library/windows/desktop/aa363258%28v=vs.85%29.aspx
*/

int RS232_IsDCDEnabled(int comport_number)
{
	int status;

	GetCommModemStatus(Cport[comport_number], (LPDWORD)((void *)&status));

	if (status&MS_RLSD_ON) return(1);
	else return(0);
}


int RS232_IsCTSEnabled(int comport_number)
{
	int status;

	GetCommModemStatus(Cport[comport_number], (LPDWORD)((void *)&status));

	if (status&MS_CTS_ON) return(1);
	else return(0);
}


int RS232_IsDSREnabled(int comport_number)
{
	int status;

	GetCommModemStatus(Cport[comport_number], (LPDWORD)((void *)&status));

	if (status&MS_DSR_ON) return(1);
	else return(0);
}


void RS232_enableDTR(int comport_number)
{
	EscapeCommFunction(Cport[comport_number], SETDTR);
}


void RS232_disableDTR(int comport_number)
{
	EscapeCommFunction(Cport[comport_number], CLRDTR);
}


void RS232_enableRTS(int comport_number)
{
	EscapeCommFunction(Cport[comport_number], SETRTS);
}


void RS232_disableRTS(int comport_number)
{
	EscapeCommFunction(Cport[comport_number], CLRRTS);
}


#endif


void RS232_cputs(int comport_number, unsigned char *text)  /* sends a string to serial port */
{
	while (*text != 0)   RS232_SendByte(comport_number, *(text++));
}