Memristor-Robotics/mep-master

#include "rs485.h"

#define TAG "RS485 "

rs485Connection::rs485Connection(bool openNow, speed_t baudRate):baudRate(baudRate)
{
    fd = -1;
    if(openNow)
    {
        openUart();
    }
}

rs485Connection::~rs485Connection()
{
    closeUart();
}

int rs485Connection::openUart()
{
    if ( (fd = open(RS485_DEVICE, O_RDWR | O_NOCTTY | O_NDELAY)) < 0 )
    {
        LOG(ERROR) << TAG << "Failed to open " << RS485_DEVICE << ". Possible causes:\n" <<
            "\t1) The raspicomm device driver is not loaded. type 'lsmod' and verify that you 'raspicommrs485'\n" <<
            "\t2) The raspicomm device driver is in use. Is another application using the device driver?\n" <<
            "\t3) Something went wrong when loading the device driver. Type 'dmesg' and check the kernel messages";
        return -1;
    }

    LOG(INFO) << TAG << "Device " << RS485_DEVICE << " opened";

    struct termios tty;
    memset (&tty, 0, sizeof tty);
    if (tcgetattr (fd, &tty) != 0)
    {
        LOG(ERROR) << TAG << "Error using tcgetattr";
        return -2;
    }

    cfsetospeed (&tty, baudRate);
    cfsetispeed (&tty, baudRate);

    tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8;     // 8-bit chars
    // disable IGNBRK for mismatched speed tests; otherwise receive break
    // as \000 chars
    tty.c_iflag &= ~IGNBRK;         // ignore break signal
    tty.c_lflag = 0;                // no signaling chars, no echo,
                                  // no canonical processing
    tty.c_oflag = 0;                // no remapping, no delays
    tty.c_cc[VMIN]  = 0;            // read doesn't block
    tty.c_cc[VTIME] = 5;            // 0.5 seconds read timeout

    tty.c_iflag &= ~(IXON | IXOFF | IXANY); // shut off xon/xoff ctrl

    tty.c_iflag &= ~(ICRNL | IGNCR); // don't ignore carriage return, don't convert carriage return to line feed

    tty.c_cflag |= (CLOCAL | CREAD);// ignore modem controls,
                                  // enable reading
    tty.c_cflag &= ~(PARENB | PARODD);      // shut off parity
    tty.c_cflag |= 0;
    tty.c_cflag &= ~CSTOPB;
    tty.c_cflag &= ~CRTSCTS;

    if (tcsetattr (fd, TCSANOW, &tty) != 0)
    {
        LOG(ERROR) << TAG << "Error caused by tcsetattr";
        return -3;
    }

    return 1;
}

void rs485Connection::closeUart()
{
    LOG(INFO) << TAG << "Uart closed";
    close(fd);
    fd = -1;
}

void rs485Connection::putString(const char *data, int dataSize)
{
    if (fd != -1)
    {
        int count = write(fd, data, dataSize); //Filestream, bytes to write, number of bytes to write
        if (count < 0)
        {
            LOG(ERROR) << TAG << "Uart TX Error";
        }
    }
}

void rs485Connection::putChar(const char &data)
{
    putString(&data, 1);
}

int rs485Connection::getString(char output[], int numOfBytes)
{
    int rv,i,numOfBytesReceived;
    fd_set set;
    struct timeval timeout;

    FD_ZERO(&set); /* clear the set */
    FD_SET(fd, &set); /* add our file descriptor to the set */

    timeout.tv_sec = 0;
    timeout.tv_usec = 200000;
    numOfBytesReceived = 0;
    if (fd != -1)
    {
        for(i=0; i<20; i++) // pokusa 20 puta
        {
            rv = select(fd + 1, &set, NULL, NULL, &timeout);
            if(rv == -1)
            {
                LOG(ERROR) << TAG << "Select error";
                return -1;
            }
            else if(rv == 0)
            {
//                printf("select timeout in attempt %d \n", i); // a timeout occured
                return numOfBytesReceived;
            }
            else
            {
                //----- CHECK FOR ANY RX BYTES -----
                int rx_length = read(fd, (void*)(output+numOfBytesReceived), numOfBytes-numOfBytesReceived);        //Filestream, buffer to store in, number of bytes to read (max)

                if (rx_length < 0)
                {
                    //An error occured (will occur if there are no bytes)
                    LOG(ERROR) << TAG << "An error occured (will occur if there are no bytes)";
                    return -1;
                }
                else if (rx_length == 0)
                {
                    //No data waiting
                    LOG(DEBUG) << TAG << "Received " << numOfBytesReceived << " of " << numOfBytes;
                }
                else
                {
                    usleep(100);

                    numOfBytesReceived += rx_length;
                    if(numOfBytes == numOfBytesReceived)
                    {
                        return numOfBytesReceived;
                    }
                }
            }
        }
    }
    return numOfBytesReceived;
}

int rs485Connection::getChar(char *data)
{
    return getString(data, 1);
}

//}