serial.cpp

嵌入式pxa 270平台上的GPS和GSM通信实验

#include "serial.h"

static struct termios termios_old, termios_new;  
//static fd_set   fs_write;
//static struct timeval tv_timeout;

Serial::Serial()
{

}
Serial::~Serial()
{

}
int Serial::_BaudRate(int baudrate)
{
    switch(baudrate)
    {
    case B2400:
	return (2400);	
    case B4800:
	return (4800);
    case B9600:
	return (9600);
    case B19200:
	return (19200);
    case B38400:
	return (38400);
    case B57600:
	return (57600);
    case B115200:
	return (115200);
    default:
	return (9600);
    }
    
}

int Serial::BaudRate( int baudrate)
{
    switch(baudrate)
    {
    case 0:
	return (B2400);
    case 1:
	return (B4800);
    case 2:
	return (B9600);
    case 3:
	return (B19200);
    case 4:
	return (B38400);
    case 5:
	return (B57600);
    case 6:
	return (B115200);
    default:
	return (B9600);
    }
}

int Serial::setPara(int serialfd,int speed,int databits , int stopbits ,int parity )
{
    bzero( &termios_new, sizeof(termios_new));
    cfmakeraw(&termios_new);
    termios_new.c_cflag=BaudRate(speed);
    termios_new.c_cflag |= CLOCAL | CREAD;
    
    termios_new.c_cflag &= ~CSIZE;
    switch (databits) //设置数据位
    {
    case 0:
	termios_new.c_cflag |= CS8;
	break;
    case 1:
	termios_new.c_cflag |= CS7;
	break;		
    case 2:
	termios_new.c_cflag |= CS6;
	break;
    case 3:
	termios_new.c_cflag |= CS5;
	break;		
    default:
	termios_new.c_cflag |= CS8;
	break;	
    }
	
    switch (parity) //设置奇偶位	    
    {
    case 0:  				//as no parity
	termios_new.c_cflag &= ~PARENB;    //Clear parity enable 
	break;	
    case 1:	
	termios_new.c_cflag |= PARENB;     // Enable parity 
	termios_new.c_cflag &= ~PARODD;   
	break;
    case 2:	
	termios_new.c_cflag |= PARENB;  
	termios_new.c_cflag |= ~PARODD;
	break;	
    default:
	termios_new.c_cflag &= ~PARENB;   // Clear parity enable 
	break;	    		
    }
    switch (stopbits)// set Stop Bit
    {
    case 0:
	termios_new.c_cflag &= ~CSTOPB;
	break;
    case 1:
	termios_new.c_cflag |= CSTOPB;
	break;
    default:
	termios_new.c_cflag &= ~CSTOPB;
	break;		
    }
    tcflush(serialfd,TCIFLUSH); // Update the termios_new and do it NOW 
    termios_new.c_cc[VTIME] = 1; /* unit: 1/10 second. */
    termios_new.c_cc[VMIN] = 1; /* minimal characters for reading */
    tcflush (serialfd, TCIFLUSH);
    return tcsetattr(serialfd,TCSANOW,&termios_new);
} 

int Serial::nwrite (int serialfd, const char *data, int datalength )
{
    //int retval, 
    int len = 0, total_len = 0;//modify8.8
    //FD_ZERO (&fs_write);
    //FD_SET (serialfd, &fs_write);
    //tv_timeout.tv_sec = TIMEOUT_SEC( datalength,GetBaudRate());
    //tv_timeout.tv_usec = TIMEOUT_USEC;

    for (total_len = 0 ; total_len < datalength;) 
    {
	len = 0;
        //retval = select (serialfd + 1, NULL, &fs_write, NULL, &tv_timeout);
        //if (retval) 
	//{
	    len = ::write(serialfd, &data[total_len], datalength - total_len);
            if (len > 0) 
                total_len += len;          
        //}
       // else 
	//{
   //         tcflush (serialfd, TCOFLUSH);     /* flush all output data */
     //       break;
       // }
    }
    return (total_len);
}

int Serial::GetBaudRate()
{
    return (_BaudRate(cfgetospeed(&termios_new)));
}
void Serial::closePort(int serialfd)
{
    tcsetattr (serialfd, TCSADRAIN, &termios_old);
    ::close (serialfd);
}

int  Serial::openPort(int index)
{
    char *device;
    switch(index)
    {
    case 0:
	device="/dev/ttyS0";
	break;	
    case 1:
	device="/dev/ttyS1";
	break;
    case 2:
	device="/dev/ttyS2";
	break;
    case 3:
	device="/dev/ttyS3";
	break;
    default:
	device="/dev/ttyS0";
    }
			
    int fd=open( device, O_RDWR | O_NOCTTY | O_NONBLOCK);
    if ( fd<0)
    { 
	//QMessageBox::information(this,"Information","Can't Open the Serial Port");
	return -1;
    }
    tcgetattr(fd , &termios_old);
    
	return fd;
    }