LxSerial.cpp

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//============================================================================
// Name        : LxSerial.cpp
// Author      : Eelko van Breda,www.dbl.tudelft.nl
// Version     : 0.1
// Copyright   : Copyright (c) 2008 LGPL
// Description : serial communicatin class linux
//============================================================================

#include <stdio.h>

#include <threemxl/platform/hardware/serial/LxSerial.h>


/*      constructor */
LxSerial::LxSerial()
{
        hPort                   = INVALID_DEVICE_HANDLE;
//      b_initialised   = false;
        b_clear_echo    = false;
        b_hw_flow_control = false;
}

/* return name of the port that was opened */
std::string& LxSerial::get_port_name()
{
        return s_port_name;
}

void LxSerial::set_port_type(LxSerial::PortType port_type)
{
        switch (port_type)
        {
                case RS232:
                        b_rts                           =       false;
                        break;

                case RS485_FTDI:
                        b_rts                           =       false;
                        break;

                case RS485_EXAR:
                        b_rts                           =       true;
                        b_clear_echo            =       true;
                        break;

                case RS485_SMSC:
                        b_rts                           =       false;
                        b_clear_echo            =       true;
                        break;

                default:
                        perror("LxSerial: no port type specified");
                        break;
        }
}

/* open port */
bool LxSerial::port_open(const std::string& portname, LxSerial::PortType port_type)
{
        // Set port type
        set_port_type(port_type);

        // Open port
        hPort = open(portname.c_str(), O_RDWR | O_NOCTTY | O_NDELAY);                                           // open the serial device
                                                                                                                                                                // O_RDWR = open read an write
                                                                                                                                                                // The O_NOCTTY flag tells UNIX that this program doesn't want to be the "controlling terminal" for that 
                                                                                                                                                                // port. If you don't specify this then any input (such as keyboard abort signals and so forth) will affect 
                                                                                                                                                                // your process. Programs like getty(1M/8) use this feature when starting the login process, but normally a 
                                                                                                                                                                // user program does not want this behavior.
                                                                                                                                                                // The O_NDELAY flag tells UNIX that this program doesn't care what state the DCD signal line is in ­ 
                                                                                                                                                                // whether the other end of the port is up and running. If you do not specify this flag, your process will be 
                                                                                                                                                                // put to sleep until the DCD signal line is the space voltage.

        if (hPort < 0) {                                                                                                                        //check if port opened correctly
                perror(" Could not open serial port, aborting");
                return false;
        }


        tcgetattr(hPort, &options);                                                                     // get the current termios (com port options struct) from the kernel
        tcgetattr(hPort, &old_options);                                                                 // get the current termios copy to restore on close

        cfsetispeed(&options, B115200);                                                                 // set incomming baudrate to standard 9600, this can be changed with the function set_speed()
        cfsetospeed(&options, B115200);                                                                 // set outgoing baudrate to standard 9600

                                                                                                                                        // c_cflag Control Options
                                                                                                                                        // |= (..) means enabled
                                                                                                                                        // &= ~(..) means not enabled
        options.c_cflag |= (CLOCAL|CREAD|CS8);                                                          // CREAD = enanble receiver
                                                                                                                                        // CLOCAL = Local Line, do not change owner of port
                                                                                                                                        // CS8 = 8 databits
        options.c_cflag &= ~(CRTSCTS|PARENB|CSTOPB);                                    // Disable HW flow control
                                                                                                                                        // no paritybit, PARENB = paritybit
                                                                                                                                        // 1 stop bit, CSTOPB = 2 stop bits (1 otherwise)
        if (b_hw_flow_control){
                options.c_cflag |= (CRTSCTS);                                                           // Enable HW flow control
        }

                                                                                                                                        // c_lflag Line Options ( controls how input charackters are handeled by the serial driver
        options.c_lflag &= ~(ECHO|ECHONL|ECHOE|ICANON|ISIG|IEXTEN);
//      options.c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
                                                                                                                                        // ~(..) means not enabled
                                                                                                                                        // ECHO echoing of input characters
                                                                                                                                        // ECHOE echo erease character as BS-SP-BS
                                                                                                                                        // ECHONL mimics echo but doesn't move to next line when it ends
                                                                                                                                        // ICANON cononical input = line oriented input, else RAW
                                                                                                                                        // ISIG ENABLE SIGINTR, SIGSUSP, SIGDSUSP and SIGQUIT signals
                                                                                                                                        // IEXTERN = enable extended functions

                                                                                                                                        // c_iflag Input Options
        options.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON|IXOFF);
//      options.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
                                                                                                                                        // ~(..) means not enabled
                                                                                                                                        // IGNBRK ignore break condition
                                                                                                                                        // BRKINT send a SIGINT when a break condition is detected
                                                                                                                                        // PARMRK Mark parity errors
                                                                                                                                        // ISTRIP strip parity bits
                                                                                                                                        // INLCR map new line to CR
                                                                                                                                        // IGNCR ignore CR
                                                                                                                                        // ICRNL map CR to new line
                                                                                                                                        // IXON Enable software flow control (outgoing)
                                                                                                                                        // IXOFF Enable software flow control (incomming)

                                                                                                                                        // c_oflag output options
        options.c_oflag &= ~(OPOST);
                                                                                                                                        // ~(..) means not enabled
                                                                                                                                        // OPOST postprocess output (if not set RAW output)
                                                                                                                                        // when OPOST is disabled all other other option bits of c-Oflag are ignored

                                                                                                                                        // c_cc control character array (control caracter options and timeouts
                                                                                                                                        // Timeout 0.005 sec for first byte, read minimum of 0 bytes
                                                                                                                                        // timeouts are ignored in cononical input or when NDELAY option is set.
        options.c_cc[VMIN]     = 0;                                                                     // VMIN Minimum number of characters to read
        options.c_cc[VTIME]    = WAIT_FOR_DATA_DSEC;                                    // Time to wait for data (tenths of seconds)

//              fcntl(hPort, F_SETFL, FNDELAY); // don't wait for input when reading data

        if (b_rts){                                                                                                             // if we are using RS_485_EXAR type, we clear the RTS signal
                int msc = TIOCM_RTS;
                ioctl(hPort, TIOCMBIC, &msc);                                                           // Clear RTS signal
                usleep(100);                                                                                            // WAIT FOR SIGNAL TO BE CLEARD
        }



        if (tcsetattr(hPort,TCSANOW, &options)!=0){                                             // Set the new options for the port now
                perror("Error: Could not set serial port settings");
                return false;
        }

        usleep(100);                                                                                                    // additional wait for correct functionality
        tcflush(hPort, TCIOFLUSH);                                                                              // flush terminal data

        // Save port name
        s_port_name = portname;

        return true;
}

bool    LxSerial::is_port_open()
{
        return hPort >= 0;
}

// speedcontrol */
bool    LxSerial::set_speed( LxSerial::PortSpeed baudrate )
{
#ifdef __APPLE__
        int speed = baudrate;
        if ( ioctl( hPort, IOSSIOSPEED, &speed ) == -1 )
        {
                perror("Error: Could not set serial port baudrate");
                return false;
        }
#else
        cfsetispeed(&options, baudrate);                                                                //set incoming baud rate
        cfsetospeed(&options, baudrate);                                                                //set outgoing baud rate

        if (tcsetattr(hPort,TCSANOW, &options)!=0){                                             // Set the new options for the port now
                perror("Error: Could not set serial port baudrate");
                return false;
        }
        usleep(100);                                                                                                    // additional wait for correct functionality
        tcflush(hPort, TCIOFLUSH);                                                                              // flush terminal data
#endif
        return true;
}

bool LxSerial::set_speed_int(const int baudrate)
{
        LxSerial::PortSpeed baud;
        // Baud rate conversion from index to real baud rate :(
        switch (baudrate)
        {
                case 4000000:   baud = S4000000;        break;
                case 3500000:   baud = S3500000;        break;
                case 3000000:   baud = S3000000;        break;
                case 2500000:   baud = S2500000;        break;
                case 2000000:   baud = S2000000;        break;
                case 1500000:   baud = S1500000;        break;
                case 1152000:   baud = S1152000;        break;
                case 1000000:   baud = S1000000;        break;
                case 921600:    baud = S921600; break;
                case 576000:    baud = S576000; break;
                case 500000:    baud = S500000; break;
                case 460800:    baud = S460800; break;
                case 230400:    baud = S230400; break;
                case 115200:    baud = S115200; break;
                case 57600:             baud = S57600;  break;
                case 38400:             baud = S38400;  break;
                case 19200:             baud = S19200;  break;
                case 9600:              baud = S9600;   break;
                case 4800:              baud = S4800;   break;
                case 2400:              baud = S2400;   break;
                case 1800:              baud = S1800;   break;
                case 1200:              baud = S1200;   break;
                case 600:               baud = S600;    break;
                case 300:               baud = S300;    break;
                case 200:               baud = S200;    break;
                case 150:               baud = S150;    break;
                case 134:               baud = S134;    break;
                case 110:               baud = S110;    break;
                case 75:                baud = S75;             break;
                case 50:                baud = S50;             break;
                default:
                        printf("This is not a legal portspeed!\n");
                        return false;
        }

        set_speed(baud);
        return true;
}

// clear echoed characters from input and detect collisions on write, use for EXAR RS485
void    LxSerial::set_clear_echo(bool clear)
{
        b_clear_echo = clear;
}

// close the serial port
bool    LxSerial::port_close()
{
        if (hPort==INVALID_DEVICE_HANDLE)
                return true;

        if (tcsetattr(hPort,TCSANOW, &old_options)!=0) {                                // restore the old port settings
                perror("Warning: Could not restore serial port settings.");
        }

        if(close(hPort) == -1) {                                                                                //close serial port
                perror("Error: Could not close serial port.");
                return false;
        }
        hPort = INVALID_DEVICE_HANDLE;
        return true;
}

int             LxSerial::port_read(unsigned char* buffer, int numBytes) const
{
        int nBytesRead = read(hPort, buffer, numBytes);

        #ifdef __DBG__
        printf("read  ");
        for (int i=0;i<nBytesRead;i++)
                { printf("%02X ",buffer[i]); }
        printf("(%d)\n",nBytesRead);
        #endif

        return nBytesRead;
}

int     LxSerial::port_read(unsigned char* buffer, int numBytes, int seconds, int microseconds)
{
        // Init time variables (they are decreased by wait_for_input)
        int s = seconds;
        int us = microseconds;
        int nBytesRead = 0;
        while (nBytesRead < numBytes)
        {
                if( wait_for_input( &s, &us) )
                {
                        int partialRead = read(hPort, buffer + nBytesRead, numBytes - nBytesRead); // Read data
                        nBytesRead += partialRead;
                }
                else
                {
                        #ifdef __DBG__
                        printf("Read Timeout... \n");
                        #endif
                        return READ_ERROR;
                }
        }

        #ifdef __DBG__
        printf("read  ");
        for (int i=0;i<nBytesRead;i++)
                { printf("%02X ",buffer[i]); }
        printf("(%d)\n",nBytesRead);
        #endif

        return nBytesRead;
}

bool    LxSerial::wait_for_input(int *seconds, int *microseconds)
{
        fd_set readset;
        timeval timeout;
        timeout.tv_sec = *seconds;                                                                              // seconds
        timeout.tv_usec = *microseconds;                                                                        // microseconds
        FD_ZERO(&readset);                                                                                      // clear file discriptor
        FD_SET(hPort, &readset);                                                                                // set filediscripter for port
        int res = select(hPort+1, &readset, NULL, NULL, &timeout);      // wait till readable data is in the buffer
        *seconds = timeout.tv_sec;
        *microseconds = timeout.tv_usec;
        return res == 1;
}

int             LxSerial::port_write(unsigned char* buffer, int numBytes)
{
        int msc = TIOCM_RTS;
        if (b_rts){                                                                                                             // control the RTS signal if needed
                ioctl(hPort, TIOCMBIS, &msc);                                                           // before you write set RTS signal
                usleep(1000);                                                                                           // wait until the RTS signal is high
        }

        int numBytesWritten = write(hPort, buffer, numBytes);                   // write data

        if (numBytes != numBytesWritten){
                perror("Error while writing to serial port");
                assert(numBytes == numBytesWritten);
        }

        #ifdef __DBG__
        printf("write ");
        for (int i=0;i<numBytes;i++)
                { printf("%02X ",buffer[i]); }
        printf("(%d)",numBytesWritten);
        printf("\n");
        #endif

        tcdrain(hPort);                                                                                                 // Wait till all the data in the buffer is transmitted

        if (b_rts){                                                                                                             // control the RTS signal if needed
                ioctl(hPort, TIOCMBIC, &msc);                                                           // Clear Ready To Send signal
        }

        if (b_clear_echo)
        {                                                                                               // Read echo from line and detect collisions if neened
                unsigned char* echo_buffer = new unsigned char[numBytes];
                int nBytesRead = 0;
                int s = ECHO_WAIT_TIME_SEC;
                int us = ECHO_WAIT_TIME_USEC;
                while (nBytesRead < numBytesWritten)
                {
                        if (wait_for_input(&s , &us))
                                nBytesRead = read(hPort, echo_buffer + nBytesRead, numBytes - nBytesRead);              // Read back ECHO of sended data
                        else
                        {
                                #ifdef __DBG__
                                printf("echo read back timeout\n");
                                #endif
                                delete[] echo_buffer;
                                return ECHO_TIMEOUT_ERROR;
                        }
                }


                #ifdef __DBG__
                printf("echo  ");
                for (int i=0;i<nBytesRead;i++)
                        { printf("%02X ",buffer[i]); }
                printf("(%d)\n",nBytesRead);
                #endif

                if (nBytesRead!=numBytesWritten)
                {
                        #ifdef __DBG__
                        printf("Warning: nr. of characters echoed not correct\n");
                        #endif
                        delete[] echo_buffer;
                        return READ_ERROR;
                }

                if (memcmp(buffer,echo_buffer, numBytes)!=0)
                {
                        #ifdef __DBG__
                        printf("collition detect\n");
                        #endif
                        usleep(COLLISION_WAIT_TIME_USEC);                                                       //wait for a while
                        tcflush(hPort, TCIFLUSH);                                                               //empty all data that was in read buffer but has not been read
                        delete[] echo_buffer;
                        return COLLISION_DETECT_ERROR;
                }
                delete[] echo_buffer;
        }

        return numBytesWritten;
}

void LxSerial::flush_buffer()
{
        tcflush(hPort, TCIOFLUSH);                                                                              // flush data buffer
}

LxSerial::~LxSerial()
{
        // Warn when you forgot to close the port before destruction.
        // We CANNOT call port_close() here, because port_close is a virtual function
        // and virtual functions cannot be called in constructors and destructors.
        if (hPort != INVALID_DEVICE_HANDLE)
                printf("[LxSerial] Warning: you didn't call port_close before calling the destructor.\n");
}