linux下,串口可写但是不能读,望高手指点__newtio_c_cflag_include_break_case_

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linux下,串口可写但是不能读,望高手指点

来源: 互联网发布时间：2016-05-04

本文导语: 三星2410的开发板,内核为2.6.18,串口通信程序如下: #include #include #include #include #include #include #include #include #include int set_opt(int fd,int nSpeed, int nBits, char nEvent, int nStop) { struct termios newtio,oldtio; if ( ...

三星2410的开发板,内核为2.6.18,串口通信程序如下:
#include
#include
#include
#include
#include
#include
#include
#include
#include

int set_opt(int fd,int nSpeed, int nBits, char nEvent, int nStop)
{
struct termios newtio,oldtio;
if  ( tcgetattr( fd,&oldtio)  !=  0) {
perror("SetupSerial 1");
return -1;
}
bzero( &newtio, sizeof( newtio ) );
newtio.c_cflag  |=  CLOCAL | CREAD;
newtio.c_cflag &= ~CSIZE;

switch( nBits )
{
case 7:
newtio.c_cflag |= CS7;
break;
case 8:
newtio.c_cflag |= CS8;
break;
}

switch( nEvent )
{
case 'O':
newtio.c_cflag |= PARENB;
newtio.c_cflag |= PARODD;
newtio.c_iflag |= (INPCK | ISTRIP);
break;
case 'E':
newtio.c_iflag |= (INPCK | ISTRIP);
newtio.c_cflag |= PARENB;
newtio.c_cflag &= ~PARODD;
break;
case 'N':
newtio.c_cflag &= ~PARENB;
break;
}

switch( nSpeed )
{
case 2400:
cfsetispeed(&newtio, B2400);
cfsetospeed(&newtio, B2400);
break;
case 4800:
cfsetispeed(&newtio, B4800);
cfsetospeed(&newtio, B4800);
break;
case 9600:
cfsetispeed(&newtio, B9600);
cfsetospeed(&newtio, B9600);
break;
case 115200:
cfsetispeed(&newtio, B115200);
cfsetospeed(&newtio, B115200);
break;
default:
cfsetispeed(&newtio, B9600);
cfsetospeed(&newtio, B9600);
break;
}
if( nStop == 1 )
newtio.c_cflag &=  ~CSTOPB;
else if ( nStop == 2 )
newtio.c_cflag |=  CSTOPB;
newtio.c_cc[VTIME]  = 0;
newtio.c_cc[VMIN] = 0;
tcflush(fd,TCIFLUSH);
if((tcsetattr(fd,TCSANOW,&newtio))!=0)
{
perror("com set error");
return -1;
}
printf("set done!n");
return 0;
}

int open_port(int fd,int comport)
{
char *dev[]={"/dev/ttyS0","/dev/ttyS1","/dev/ttyS2"};
long  vdisable;
if (comport==1)
{ fd = open( "/dev/ttyS0", O_RDWR|O_NOCTTY|O_NDELAY);
if (-1 == fd){
perror("Can't Open Serial Port");
return(-1);
}
else
printf("open ttyS0 .....n");
}
else if(comport==2)
{ fd = open( "/dev/qq", O_RDWR|O_NOCTTY|O_NDELAY);
if (-1 == fd){
perror("Can't Open Serial Port");
return(-1);
}
else
printf("open ttyS1 .....n");
}
else if (comport==3)
{
fd = open( "/dev/ttyS2", O_RDWR|O_NOCTTY|O_NDELAY);
if (-1 == fd){
perror("Can't Open Serial Port");
return(-1);
}
else
printf("open ttyS2 .....n");
}
if(fcntl(fd, F_SETFL, 0)