serialfunc.c

本程序是在LINUX下编写的串口程序设计

#include "serialfunc.h"

#include <gtk/gtk.h>
#include <signal.h>
#include <stdio.h>
#include <termios.h>
#include <fcntl.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>

static speed_t baud_rate = B115200;
static gint bit_size = 8;
static gint checkmod = 0;			// 0:none ; 1:odd ; 2:even
static struct termios term,termsave;
static FILE* fp = NULL;				//file pointer for serial port
static gchar* port = NULL;

void tty_set_port(const gchar* portname)
{
	if (portname == NULL)
	{
		g_warning("portname can not be NULL");
		return;
	}
	if (port != NULL)
		free(port);
	port = strdup(portname);
}

void tty_set_baud_rate(speed_t speed)
{
	baud_rate = speed;
}

void tty_set_bit_size(gint size)
{
	bit_size = size;
}

void tty_set_checkmod(gint mod)
{
	checkmod = mod;
}

FILE* tty_get_fp()
{
	return fp;
}

gint tty_serial_open()
{		
	gint fd;
	gint accessmod;
		
	if ((fp = fopen(port,"rb+")) == NULL)
	{
		g_warning("error open %s\n",port);
		return -1;
	}
	setbuf(fp,NULL);
	fd = fileno(fp);
	
	accessmod = fcntl(fd,F_GETFL,0);
	
	if ( tcgetattr(fd,&termsave)<0 )
	{
		g_print("error in tcgetattr %s\n",port);
		fclose(fp);
		return -1;
	}
	
	if ( fcntl(fd,F_SETFL,accessmod|O_NONBLOCK) == -1)
	{
		g_warning("change access mod to nonblock failed\n");
		fclose(fp);
		return -1;
	}
	
	term = termsave;

	//g_print("inlcr = %d\n",term.c_iflag & INLCR);
	//g_print("icrnl = %d\n",term.c_iflag & ICRNL);
	//g_print("Echonl = %d\n",term.c_lflag & ECHONL);
	//g_print("echo = %d\n",term.c_iflag & ECHO);

	// disable nl=>cr translate
	// disable cr=>nl translate
	// no SIGINT on BREAK, output flow control off
	term.c_iflag &= ~(INLCR|ICRNL|BRKINT|IXON);
	
	// disable nl echo
	// disable echo
	// extended ipnut processing off, signal chars off
	// canonical mode off i.e. terminal not in line buffer mode
	term.c_lflag &= ~(ECHONL|ECHO|IEXTEN|ISIG|ICANON);

	// output processing off
	term.c_oflag &= ~(OPOST);
	
	term.c_cc[VMIN] = TTY_MIN_READ_SIZE;
	term.c_cc[VTIME] = TTY_RETURN_TIME;
	
	//-------------- set serial port's baud_rate ----------------
	if ( cfsetospeed(&term,baud_rate)<0 )
	{
		g_warning("set serial output baud rate error\n");
		fclose(fp);
		return -1;
	}
    if ( cfsetispeed(&term,baud_rate)<0 )
    {
        g_warning("set serial input baud rate error\n");
		fclose(fp);
        return -1;
    }

	//------------- set serial port's bits per byte ---------------
	switch(bit_size)
	{
		case 5:
			term.c_cflag &= ~(CSIZE);
			term.c_cflag |= CS5;
			break;
		case 6:
			term.c_cflag &= ~(CSIZE);
			term.c_cflag |= CS6;
			break;
		case 7:
			term.c_cflag &= ~(CSIZE);
			term.c_cflag |= CS7;
			break;
		case 8:
			term.c_cflag &= ~(CSIZE);
			term.c_cflag |= CS8;
			break;
		default:
			g_warning("set bit_size failed\n");
			fclose(fp);
			return -1;
	}

	//-------- set serial port's odd\even check mode -------------
	switch(checkmod)
	{
		case 0:
			term.c_cflag &= ~(PARENB);
			break;
		case 1:
			term.c_cflag |= PARENB;
			term.c_cflag |= PARODD;
			break;
		case 2:
			term.c_cflag |= PARENB;
			term.c_cflag |= ~(PARODD);
			break;
		default:
			g_warning("set checkmod failed\n");
			fclose(fp);
			return -1;
	}

	//------- only now really set the serial port's parameters ------------
	if ( tcsetattr(fd,TCSANOW,&term)<0 )
	{	
		g_warning("error tcsetattr %s\n",port);
		fclose(fp);
		return -1;
	}

	return 0;

}

void tty_serial_close()
{
	if (fp == NULL)
		return;
	
	// restore the terminal's mode
	if ( tcsetattr(fileno(fp),TCSANOW,&termsave)<0 )
	{	
		g_warning("error tcsetattr");
	}
	
	if (tcflush(fileno(fp),TCIOFLUSH) == -1)
		g_warning("tcflush error\n");
	fclose(fp);
	fp = NULL;
}


gint tty_read_data(gint event_fd,gchar* buffer,gint size)
{
	gint readsize;

	if( event_fd == fileno(fp) )
	{
		readsize = read(fileno(fp),buffer,size-1);
		if (readsize == -1)
		{
			g_warning("read data from serial error");
			buffer[0] = '\0';
		}
		else
		{
			buffer[readsize] = '\0';
		}
	}
	else
	{
		g_warning("should not come here\n");
		buffer[0] = '\0';
	}

	return readsize;
}

int tty_write_data(const gchar* text)
{
	int count;
	int i;
	size_t length;
	
	if ( fp == NULL )
		return EOF;
	count = 0;
	length = strlen(text);
	for (i=0;i<length;i++)
	{
		if( fputc(text[i],fp) != EOF)
		{
			count++;
		}
	}
	return count;
//	fputs("\r\n",fp);

}