serialcomm.cpp

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/*
 * serialcomm.cpp
 *
 *  Created on: June 05, 2012
 *      Author: mwalecki
 */

#include <math.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <cstring>
#include <iostream>

#include "serialcomm.hpp"

using namespace std;

SerialComm::SerialComm(const std::string& port, int baud) {
        connected = false;

        fd = open(port.c_str(), O_RDWR | O_NOCTTY | O_NDELAY);
        if (fd >= 0) {
                tcgetattr(fd, &oldtio);

                // set up new settings
                struct termios newtio;
                memset(&newtio, 0, sizeof(newtio));
                newtio.c_cflag = CBAUD | CS8 | CLOCAL | CREAD | CSTOPB;
                newtio.c_iflag = INPCK | IGNPAR;
                newtio.c_oflag = 0;
                newtio.c_lflag = 0;
                //newtio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); //####
                if (cfsetispeed(&newtio, baud) < 0 || cfsetospeed(&newtio, baud) < 0) {
                        fprintf(stderr, "Failed to set serial baud rate: %d\n", baud);
                        tcsetattr(fd, TCSANOW, &oldtio);
                        close(fd);
                        fd = -1;
                        return;
                }
                // activate new settings
                tcflush(fd, TCIFLUSH);
                tcsetattr(fd, TCSANOW, &newtio);
                //fcntl(fd, F_SETFL, FNDELAY);  //####
                connected = true;
        }
}

SerialComm::~SerialComm() {
        // restore old port settings
        if (fd > 0)
                tcsetattr(fd, TCSANOW, &oldtio);
        close(fd);
}

int SerialComm::write(uint8_t* buf, int len) {
        tcflush(fd, TCIFLUSH);
        return ::write(fd, buf, len);
}

int SerialComm::read(uint8_t* buf, int len) {
        return ::read(fd, (char*) buf, len);
}

uint8_t SerialComm::readOneByte() {
        uint8_t ret;
        int sel;
        struct timeval tv;

        // Prepare mask for select - Watch fd to see when it has input
        FD_ZERO(&rfds);
        FD_SET(fd, &rfds);
        do {
                printf("Read attempt.\n");
                // Prepare imeout struct for select - Wait up to five seconds
                tv.tv_sec = 5;
                tv.tv_usec = 0;
        
                sel = select(fd+1, &rfds, NULL, NULL, &tv);
                // Don't rely on the value of tv now!

                if (sel == -1)
                        perror("select()");
                else if (sel == 0)
                        printf("No data within five seconds.\n");
        } while( ::read(fd, (char*)(&ret), 1) < 1);
        return ret;
}

bool SerialComm::isConnected() {
        return connected?true:false;
}