comfp.c

linux串口函数

/*
 *  max8640.c
 *
 *  the program for matrix mode MX8640
 *
 *  Copyright v2.0  by shenbo shanghai hunda 
 *
 *  
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <termios.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <string.h>


static struct termios newtios, oldtios;		/* terminal settings */
static int saved_portfd = -1;           /* serial port fd */


/* cleanup atexit handler */
void reset_tty_atexit(void)
{
	if(saved_portfd != -1){
		tcsetattr(saved_portfd, TCSANOW, &oldtios);
	}
}

/* cleanup signal handler */
void reset_tty_handler(int signal)
{
	if(saved_portfd != -1){
		tcsetattr(saved_portfd, TCSANOW, &oldtios);
	}
	_exit(EXIT_FAILURE);
}

int open_port(const char *portname,long baud_rate,int data_bit,int stop_bit,int parity)
{
	struct sigaction sa;
	int portfd;
	long databits = 0;
	long stopbits = 0;
	long parityof = 0;
	long parityoe = 0;
	
	
	/*Useing for test the program!*/

	printf("opening serial port: %s\n", portname);

	/* open serial port */
	
	if((portfd = open(portname, O_RDWR|O_NOCTTY)) < 0){
		printf("open serial port %s fail\n", portname);
		return portfd;
	}

	/* get serial port params, save away */
	//printf("get serial port params, save away\n");
	tcgetattr(portfd, &newtios);
	memcpy(&oldtios, &newtios, sizeof newtios);

	
	
	/* Set Data_bit */
	switch(data_bit)
	{case 5:
		databits = CS5;
		break;
		
	 case 6:
	 	databits = CS6;
		break;
		
	case 7:
	 	databits = CS7;
		break;
	
	case 8:
	 	databits = CS8;
		break;
	}
	
	switch(stop_bit)
	{case 1:
		stopbits= 0;
		break;
		
	 case 2:
	 	stopbits = CSTOPB;
		break;
	}
	
	/* Set parity */
	
	switch(parity)
	{case 0:
		parityof= 0;
		parityoe= 0;
		break;
		
	 case 1:
	 	parityof= PARENB;
		parityoe= PARODD;
		break;
		
	case 2:
	 	parityof= PARENB;
		parityoe= 0;
		break;
	}
	
	/* configure new values */
	printf("configure new values\n");
	cfmakeraw(&newtios);            /* see man page */
	newtios.c_lflag &=~(ICANON|ECHO|ECHOE);
	newtios.c_iflag = INPCK|BRKINT;      /* ignore parity on input */
	newtios.c_oflag &= ~OPOST;
	
	//newtios.c_cflag = CS8|CLOCAL|CREAD;
	newtios.c_cflag = databits|stopbits|parityof|parityoe|CLOCAL|CREAD;
	newtios.c_cc[VMIN] = 1;          /*block until 1 char received */
	newtios.c_cc[VTIME] = 0;         /*no inter-character timer */
	
	/* Set BAUD */
	switch(baud_rate)
	{case 600:
		printf("configure 600 bp\n");
		cfsetospeed(&newtios, B600);
		cfsetispeed(&newtios, B600);
		break;
		
	case 1200:
		printf("configure 1200 bp\n");
		cfsetospeed(&newtios, B1200);
		cfsetispeed(&newtios, B1200);
		break;
		
	case 1800:
		printf("configure 1800 bp\n");
		cfsetospeed(&newtios, B1800);
		cfsetispeed(&newtios, B1800);
		break;
		
	case 2400:
		printf("configure 2400 bp\n");
		cfsetospeed(&newtios, B2400);
		cfsetispeed(&newtios, B2400);
		break;
		
	case 4800:
		printf("configure 4800 bp\n");
		cfsetospeed(&newtios, B4800);
		cfsetispeed(&newtios, B4800);
		break;
		
	case 9600:
		printf("configure 9600 bp\n");
		cfsetospeed(&newtios, B9600);
		cfsetispeed(&newtios, B9600);
		break;
		
	case 19200:
		printf("configure 19200 bp\n"); 
		cfsetospeed(&newtios, B19200);
		cfsetispeed(&newtios, B19200);
		break;
	
	case 38400:
		printf("configure 38400 bp\n");
		cfsetospeed(&newtios, B38400);
		cfsetispeed(&newtios, B38400);
		break;
		
	case 57600:
		printf("configure 57600 bp\n");
		cfsetospeed(&newtios, B57600);
		cfsetispeed(&newtios, B57600);
		break;	
	}
		
	

	/* register cleanup stuff  */
	//printf("register cleanup stuff\n");
	atexit(reset_tty_atexit);
	memset(&sa, 0, sizeof sa);
	sa.sa_handler = reset_tty_handler;
	sigaction(SIGHUP, &sa, NULL);
	sigaction(SIGINT, &sa, NULL);
	sigaction(SIGPIPE, &sa, NULL);
	sigaction(SIGTERM, &sa, NULL);

	/* apply modified termios */
	//printf("apply modified termios\n");
	saved_portfd = portfd;
	tcflush(portfd, TCIOFLUSH);
	tcsetattr(portfd, TCSANOW, &newtios);
	//tcsetattr(portfd, TCSADRAIN, &newtios);
	//printf("open serial port is ok!\n");
	return portfd;
	
}

void close_port(int portfd)
{
	tcsetattr(portfd, TCSANOW, &oldtios);
	close(portfd);
	saved_portfd = -1;
}