serial_test.c

Linux/Unix下串口设置、读写串口的程序

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

#define SERIAL1 	"/dev/ttyS1"
#define SERIAL2   	"/dev/ttyS2" 
#define SERIAL3 	"/dev/ttyS3"

static int speed_arr[] = {B230400, B115200, B57600, B38400, B19200, B9600, B4800, B2400, B1800, B1200, B600, B300};
static int name_arr[]  = {230400,  115200,  57600,  38400,  19200,  9600,  4800,  2400,  1800,  1200,  600,  300};


int set_speed(int fd, int speed)
{
    int   i; 
    int   status; 
    struct termios   Opt;
    
    tcgetattr(fd, &Opt); 


    for ( i= 0;  i < sizeof(speed_arr) / sizeof(int);  i++) 
	{ 
        if (speed == name_arr[i]) 
        {     
            tcflush(fd, TCIOFLUSH);     
            cfsetispeed(&Opt, speed_arr[i]);  
            cfsetospeed(&Opt, speed_arr[i]);   
            status = tcsetattr(fd, TCSANOW, &Opt);  
            if  (status != 0) 
            {        
                perror("tcsetattr fd");  
                return -1;     
            }    
            tcflush(fd,TCIOFLUSH);   
			return 0;
        }  
    }
    return -1;
}


int set_other_attribute(int fd, int databits, int stopbits, int parity)
{ 
    struct termios options; 

    if (tcgetattr(fd, &options) != 0) 
    { 
        perror("SetupSerial 1");     
        return -1;  
    }
    options.c_cflag &= ~CSIZE; 
    switch (databits) /*ÉÖʾݻÊ*/
    {   
        case 7:		
            options.c_cflag |= CS7; 
            break;
        case 8:     
            options.c_cflag |= CS8;
            break;   
        default:    
            fprintf(stderr,"Unsupported data size\n"); 
            return -1;  
    }
    switch (parity) 
    {   
        case 'n':
        case 'N':    
            options.c_cflag &= ~PARENB;   /* Clear parity enable */
            options.c_iflag &= ~INPCK;     /* Enable parity checking */ 
            break;  
        case 'o':   
        case 'O':    
		case 1:
            options.c_cflag |= (PARODD | PARENB); /* ÉÖΪÆЧÑ*/  
            options.c_iflag |= INPCK;             /* Disnable parity checking */ 
            break;  
        case 'e':  
        case 'E':   
		case 2:
            options.c_cflag |= PARENB;     /* Enable parity */    
            options.c_cflag &= ~PARODD;    /* ת»»ΪżЧÑ*/     
            options.c_iflag |= INPCK;      /* Disnable parity checking */
            break;
        case 'S': 
        case 's':  /*as no parity*/   
		case 0:
            options.c_cflag &= ~PARENB;
            options.c_cflag &= ~CSTOPB;
            break;  
        default:   
            fprintf(stderr,"Unsupported parity\n");    
            return -1;  
    }  
    /* ÉÖֹͣλ*/  
    switch (stopbits)
    {   
        case 1:    
            options.c_cflag &= ~CSTOPB;  
            break;  
        case 2:    
            options.c_cflag |= CSTOPB;  
            break;
        default:    
            fprintf(stderr,"Unsupported stop bits\n");  
            return -1; 
    } 
    /* Set input parity option */ 
    if (parity != 'n')   
        options.c_iflag |= INPCK; 
    tcflush(fd,TCIFLUSH);
    options.c_iflag = 0;
    options.c_oflag = 0;
    options.c_lflag = 0;  
    options.c_cc[VTIME] = 150; /* ÉÖ³¬ʱ15 seconds*/   
    options.c_cc[VMIN] = 0; /* Update the options and do it NOW */
//	options.c_oflag = 0;

if (tcsetattr(fd,TCSANOW,&options) != 0)   
    { 
        perror("SetupSerial 3");   
        return -1;  
    }
 
#if 0	
    tcgetattr(fd, &options);
    printf("c_iflag: %x\rc_oflag: %x\n", options.c_iflag, options.c_oflag);
    printf("c_cflag: %x\nc_lflag: %x\n", options.c_cflag, options.c_lflag);
    printf("c_line: %x\nc_cc[VTIME]: %d\nc_cc[VMIN]: %d\n", options.c_line, options.c_cc[VTIME], options.c_cc[VMIN]);
#endif
    return 0;  
}

int main(int argc, char *argv[])
{
	int fd0, fd1,fd2,fd;
	char temp[1024];
	char string[] = "this is serial test string!!\n";
	int i = 0;
	int d = 0;
	struct termios options;	

	printf("serial test ...\n");
		
	fd0 = open(SERIAL1, O_RDWR,1);	
	fd1 = open(SERIAL2, O_RDWR,1) ;
  fd2 = open(SERIAL3, O_RDWR,1) ;

	if (fd0 < 0) {
		printf("open serial 1 error! %d\n", fd0);
	}
	if (fd1 < 0) {
		printf("open serial 2 error! %d\n", fd1);
	}
  if (fd2 < 0) {
                printf("open serial 3 error! %d\n", fd2);
  }

	printf("set speed ...\n");
	set_speed(fd0, 19200);
	set_speed(fd1, 19200);
  set_speed(fd2, 19200);
	printf("set attribute ...\n");
	
	set_other_attribute(fd0, 8, 1, 0);
	set_other_attribute(fd1, 8, 1, 0);
  set_other_attribute(fd2, 8, 1, 0);
	
	if (argc < 2)
		fd = fd0;
	else {
	switch (argv[1][0]){
		case '1':
			fd = fd0;
			break;
		case '2': 
			fd = fd1;
			break;
		case '3':
			fd = fd2;
			break;
		default:
			fd = fd0;
	}}	
 
	for (;;) {
		i = read(fd, temp, 1024);
		if (i) {
			printf("(%d) ",i);
			for(d=0;d<i;d++)
			printf(" %c ",temp[d]);
			printf("\n");
			memset(temp,0,sizeof(temp));
		}
	}

	close(fd0);
	close(fd1);
	close(fd2);
	return 0;
}