论坛徽章:: 0

电梯直达

1楼 [收藏(0)] [报告]

发表于 2011-03-21 17:44 |只看该作者 |倒序浏览

哪位高手帮忙解决下问题，非常感谢！程序的代码如下所示：
#include    <stdio.h>    /* stand input and output... */
#include    <stdlib.h>    /* stand lib */
#include    <unistd.h>    /* UNIX stand function */
#include    <sys/types.h>  /**/
#include    <sys/stat.h> /**/
#include    <fcntl.h>    /* file controle */
#include    <termios.h> /*PPSIX terminal controle */
#include    <errno.h>    /* error */
#include <math.h> /**/

/************ set baud ********************/
void set_speed(int fd, int speed)
{
int status;
struct termios Opt;

tcgetattr(fd, &Opt);  // get attribute of serial port
tcflush(fd, TCIOFLUSH);
cfsetispeed(&Opt, speed);
cfsetospeed(&Opt, speed);

status = tcsetattr(fd, TCSANOW, &Opt);  // set attribute
if  (status != 0)
{
      perror("tcsetattr fd1");
      return;
}
tcflush(fd,TCIOFLUSH);
}

/*********** set data format: databits,stopbits and parity **********/
int set_data_format(int fd,int databits,int stopbits,int parity)
{
struct termios opt;

if( tcgetattr(fd, &opt)  !=  0)
{
    perror("SetupSerial 1");
    return -1;
}
opt.c_cflag &= ~CSIZE;

switch (databits)
{

case 5:
    opt.c_cflag |= CS5;
    break;
      case 6:
    opt.c_cflag |= CS6;
    break;
      case 7:
    opt.c_cflag |= CS7;
    break;
    case 8:
opt.c_cflag |= CS8;
break;
default:
fprintf(stderr,"Unsupported data size\n");
return -1;
}
switch (parity)
{
case 'n':
case 'N':
opt.c_cflag &= ~PARENB; /* Clear parity enable */
opt.c_iflag &= ~INPCK;    /* Enable parity checking */
break;
case 'o':
case 'O':
opt.c_cflag |= (PARODD | PARENB);  /* parity checking */
opt.c_iflag |= INPCK;    /* Disnable parity checking */
break;
case 'e':
case 'E':
opt.c_cflag |= PARENB;    /* Enable parity */
opt.c_cflag &= ~PARODD; /*  */
opt.c_iflag |= INPCK;    /* Disnable parity checking */
break;

default:
fprintf(stderr,"Unsupported parity\n");
return -1;
}

switch (stopbits)
{
case 1:
    opt.c_cflag &= ~CSTOPB;
break;
case 2:
opt.c_cflag |= CSTOPB;
break;
default:
fprintf(stderr,"Unsupported stop bits\n");
return -1;
}

/* Set input parity option */
if (parity != 'n')
     opt.c_iflag |= INPCK;
opt.c_cc[VTIME] = 100; // 10 seconds
opt.c_cc[VMIN] = 0;

tcflush(fd, TCIFLUSH); /* Update the options and do it NOW */
if (tcsetattr(fd, TCSANOW, &opt) != 0)
{
    perror("SetupSerial 3");
return -1;
}

return 0;
}

/************* main() ********************/
int main()
{
int fd;
unsigned char rcv[32];

fd = open("/dev/ttyS1", O_RDWR);  // read and write
if(fd == -1)
{
printf("Can't open ttyS1!\n");
exit(0);
}
set_speed(fd, B115200); // set baud 115200

if (set_data_format(fd, 8, 1, 'N')== -1)
{
      printf("Data format Error!\n");
      exit(1);
}

//recieve and send
while(1) {
read(fd, rcv, 16);// from rs232
   printf("rcv %s\n", rcv);
   write(fd, rcv, 16);
}

close(fd);
close(sd_fd);
return(0);
}
进行while循环时，只能进行read函数，下面的printf函数不执行，write也不执行。但是用串口进行调试时，发送数据正常，发送以后也回显过来。但是把printf、write注释掉的话，也会回显发送的数据！！！小弟刚开始入手Linux，很多都不会，希望高手们帮帮忙,非常感谢！！