rs232.cpp

/*
*
* Author: Teunis van Beelen
* Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014
* last revision: January 31, 2014
* teuniz@gmail.com
* http://www.teuniz.net/RS-232/
*
* 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.
*
* This version of GPL is at http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
*
*/

#include <iostream> // cout

#include "rs232.h"

using namespace std;

bool ldb = 0;                   // DP

int Cport[30], rs_error;

struct termios new_port_settings, old_port_settings[30];

char comports[30][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"
};

int comport_number = 16;        // "/dev/ttyUSB0"

//------------------------------------------------------------------------------
int RS232_OpenComport( int comport_number, int baudrate )
{
  int baudr, status;

  if( comport_number > 29 || comport_number < 0 ) {
    cout << "rs232 illegal comport number " << comport_number << endl;
    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;
  default:
    cout << "rs232: invalid baud rate " << baudrate << endl;
    return ( 1 );
    break;
  }

  rs_error = 0;
  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 );
  }

  rs_error =
    tcgetattr( Cport[comport_number], old_port_settings + comport_number );
  if( rs_error == -1 ) {
    close( Cport[comport_number] );
    perror( "unable to read port settings" );
    return ( 1 );
  }

  memset( &new_port_settings, 0, sizeof( new_port_settings ) ); // clear the new struct

  new_port_settings.c_cflag = baudr | CS8 | CLOCAL | CREAD;
  new_port_settings.c_iflag = IGNPAR;
  new_port_settings.c_oflag = 0;
  new_port_settings.c_lflag = FLUSHO;
  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.) */
  rs_error = tcsetattr( Cport[comport_number], TCSANOW, &new_port_settings );
  if( rs_error == -1 ) {
    close( Cport[comport_number] );
    perror( "rs232 unable to adjust port settings " );
    return ( 1 );
  }

  if( ioctl( Cport[comport_number], TIOCMGET, &status ) == -1 ) {
    perror( "rs232 unable to get port status" );
    return ( 1 );
  }

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

  if( ioctl( Cport[comport_number], TIOCMSET, &status ) == -1 ) {
    perror( "rs232 unable to set port status" );
    return ( 1 );
  }

  return ( 0 );
}

//------------------------------------------------------------------------------
int RS232_PollComport( int comport_number, 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 ) );
}

//------------------------------------------------------------------------------
// Simon need's this function to talk to the Keithley 2410
int RS232_SendBufString( int comport_number, 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( "rs232 unable to get port status" );

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

  if( ioctl( Cport[comport_number], TIOCMSET, &status ) == -1 )
    perror( "rs232 unable to set port status" );

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

//------------------------------------------------------------------------------
/*
  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  Synonym for TIOCM_CAR
  TIOCM_RNG RNG (ring)
  TIOCM_RI  Synonym for TIOCM_RNG
  TIOCM_DSR DSR (data set ready)

  http://linux.die.net/man/4/tty_ioctl
*/

//------------------------------------------------------------------------------
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( "rs232 unable to get port status" );

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

  if( ioctl( Cport[comport_number], TIOCMSET, &status ) == -1 )
    perror( "rs232 unable to set port status" );
}

//------------------------------------------------------------------------------
void RS232_disableDTR( int comport_number )
{
  int status;

  if( ioctl( Cport[comport_number], TIOCMGET, &status ) == -1 )
    perror( "rs232 unable to get port status" );

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

  if( ioctl( Cport[comport_number], TIOCMSET, &status ) == -1 )
    perror( "rs232 unable to set port status" );
}

//------------------------------------------------------------------------------
void RS232_enableRTS( int comport_number )
{
  int status;

  if( ioctl( Cport[comport_number], TIOCMGET, &status ) == -1 )
    perror( "rs232 unable to get port status" );

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

  if( ioctl( Cport[comport_number], TIOCMSET, &status ) == -1 )
    perror( "rs232 unable to set port status" );
}

//------------------------------------------------------------------------------
void RS232_disableRTS( int comport_number )
{
  int status;

  if( ioctl( Cport[comport_number], TIOCMGET, &status ) == -1 )
    perror( "rs232 unable to get port status" );

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

  if( ioctl( Cport[comport_number], TIOCMSET, &status ) == -1 )
    perror( "rs232 unable to set port status" );
}

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

//------------------------------------------------------------------------------
int openComPort( const int comPortNumber, const int baud )
{
  comport_number = comPortNumber;

  if( RS232_OpenComport( comport_number, baud ) ) {
    cout << "  Cannot open COM port" << endl;
    return 0;
  }
  return 1;
}

//------------------------------------------------------------------------------
void closeComPort(  )
{
  RS232_CloseComport( comport_number );
}

//------------------------------------------------------------------------------
int writeCommand( const char *command )
{
  char cmd[256];
  char buf[10] = { 0 };
  int timeout;
  int rb;
  int len;

  strncpy( cmd, command, 250 );
  cmd[250] = 0;

 // terminate command with CR LF
  if( !strstr( cmd, "\r\n" ) )
    strcat( cmd, "\r\n" );

  len = strlen( cmd );

  int i;
  for( i = 0; i < len; i++ ) {

    RS232_SendByte( comport_number, cmd[i] );

   // read echo
    timeout = 10;
    do {
      rb = RS232_PollComport( comport_number, buf, 1 );
      usleep( 10000 );
      timeout--;
    } while( ( rb == 0 ) && ( timeout > 0 ) );

    if( cmd[i] != buf[0] ) {
      return 0;
    }
  }

  usleep( 20000 );

  return 1;
}

//------------------------------------------------------------------------------
// Allows writing commands to the Keithley 2410
int writeCommandString( const char *command )
{
  int len;
  char cmd[256];

  strncpy( cmd, command, 250 );
  cmd[250] = 0;

 // terminate command with CR+ LF
  if( !strstr( cmd, "\r\n" ) )
    strcat( cmd, "\r\n" );

  len = strlen( cmd );
  RS232_SendBufString( comport_number, cmd, len );

  usleep( 20000 );

  return 1;
}

//------------------------------------------------------------------------------
int writeCommandAndReadAnswer( const char *command, char *answer )
{
  if( ldb )
    cout << "RS232 Command: " << command << endl;

  int bytesRead;
  char inbuf[256];
  int to = 0;
  char *p;

  if( !answer )
    return 0;

 // write command to HV device
  if( !writeCommand( command ) )
    return 0;

 // init buffer
  *answer = 0;

 // read answer (terminated with CR + LF)
  to = 0;
  do {
    bytesRead = RS232_PollComport( comport_number, inbuf, sizeof( inbuf ) );

    if( bytesRead > 0 ) {
      inbuf[bytesRead] = 0;
      strcat( answer, inbuf );
      to = 0;
    }
    usleep( 10000 );
  } while( ( strstr( answer, "\r\n" ) == 0 ) && ( ++to < 80 ) ); // wait for CR+LF or timeout

 //         // clear trailing CR + LF
  if( ( p = strstr( answer, "\r\n" ) ) )
    *p = 0;

  usleep( 100000 );
  if( ldb )
    cout << "RS232 Answer: " << answer << endl;
  return 1;
}

//------------------------------------------------------------------------------
// Allows writing commands to the Keithley 2410
int writeCommandStringAndReadAnswer( const char *command, char *answer,
                                     int delay )
{
  if( ldb )
    cout << "RS232 Command: " << command << endl;

  int bytesRead;
  char inbuf[256];
  int to = 0;
  char *p;

  if( !answer ) {
    return 0;
  }

 // write command to HV device
  if( !writeCommandString( command ) ) {
    return 0;
  }

  usleep( delay * 1000000 );

 // init buffer
  *answer = 0;

 // read answer (terminated with CR)
  to = 0;
  do {
    bytesRead = RS232_PollComport( comport_number, inbuf, sizeof( inbuf ) );

    if( bytesRead > 0 ) {
      inbuf[bytesRead] = 0;
      strcat( answer, inbuf );
      to = 0;
    }
    usleep( 10000 );
  } while( ( strstr( answer, "\r\n" ) == 0 ) && ( ++to < 80 ) ); // wait for CR or t$

 //         // clear trailing CR
  if( ( p = strstr( answer, "\r\n" ) ) )
    *p = 0;

  usleep( 100000 );
  if( ldb )
    cout << "RS232 Answer: " << answer << endl;
  return 1;
}