hello,

I am gettin problem while sending and recieving data through seial port...
when I am sending Data then the reciever end is not able to recieve that data .....
Reciever end is running in infinite loop just polling after some time to check that there is data on the port and then again sleeps down....

whats going wrong ....I am not getting data at the recievers End ....
here I am copying my code of both ends..........

SENDER(just writing data on Serial Port):::::::::

#include<sys/types.h>
#include<iostream.h>
#include<termios.h>
#include<fcntl.h>
#include<errno.h>
#include<sys/ioctl.h>
#include<iostream.h>
#include<unistd.h>

main ()
{

struct termios t;
char *device = "/dev/ttyS0";

int sPort, rbyte, status, sPortdest,length;
long count=0;

unsigned char send1[32];


t.c_cc[VMIN] = 1;
t.c_cc[VTIME]=0;
t.c_cc[VEOF]='\n';

/* t.c_iflag &= ~(BRKINT|IGNPAR|PARMRK|INPCK|INLCR|IGNCR|ICRNL|IXON);
t.c_iflag |= (IGNBRK|ISTRIP|IXOFF);
t.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|ICANON|ISIG|NOFLSH|TOSTOP);
t.c_cflag &= (CSIZE|CSTOPB|HUPCL|PARENB);
t.c_cflag |= (CLOCAL|CREAD|CS8);*/


t.c_iflag |= (ISIG);
// t.c_iflag &= ~BRKINT;
// t.c_iflag &= (IUCLC);
t.c_cflag = B9600 | CS8 | CREAD | CLOCAL | HUPCL;



sPort = open(device,O_RDWR|O_NOCTTY|O_NDELAY);



if(sPort != -1)
{
cout<<"open successfully\n";

status = ioctl(sPort,TCSETS,&t);
if(status==0)
{

for(count=0;count<20;count++)


{
cout<<"Enter :";
cin>>send1;
//strcat((char *)send1,"{MSS TYPE-D DAMA}");
write(sPort,"{100223456}",11);
// rbyte=write(sPort,send1,strlen((char *)send1));
cout<<"w b:"<<rbyte<<"\t Time:"<<count<<"\t string:"<<send1<<"\n";
usleep(1000);

}

}
close(sPort);

}
else
{
cout<<"Device could not be opened";
}
}


RECIEVER(just reading Data on serial port....)

#include<termios.h>
#include<fcntl.h>
#include<errno.h>
#include<sys/ioctl.h>
#include<stdio.h>
#include<sys/time.h>
#include<iostream.h>
#include<sys/types.h>
#include<unistd.h>
#include<string.h>

main ()
{

struct termios t;
char *devicedest = "/dev/ttyS0";

unsigned char recvbuf[2];
int rbyte, status, sPortdest,r,i,c=0;
long count=0;

int inp_check=0;
int ifirst=0;

struct timeval timeout;
fd_set testfds,readfds;


t.c_cc[VMIN] = 1;
t.c_cc[VTIME]=0;
t.c_cc[VEOF]='\n';
/* t.c_iflag &= ~(BRKINT|IGNPAR|PARMRK|INPCK|INLCR|IGNCR|ICRNL|IXON);
t.c_iflag |= (IGNBRK|ISTRIP|IXOFF);
t.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|ICANON|ISIG|NOFLSH|TOSTOP);
t.c_cflag &= (CSIZE|CSTOPB|HUPCL|PARENB);
t.c_cflag |= (CLOCAL|CREAD|CS8);*/
// t.c_iflag |= (ISIG);
// t.c_iflag &= ~(IUCLC);

t.c_iflag &= ~BRKINT;
t.c_iflag = (ISIG | IUCLC) ;
t.c_cflag = B9600 | CS8 | CREAD | CLOCAL| HUPCL;


sPortdest= open(devicedest,O_RDONLY|O_NOCTTY|O_NDELAY);
if(tcsetattr(sPortdest,TCSANOW,&t) != 0 )
cout<<"\n attribute not set";

FD_ZERO(&readfds);
FD_SET(sPortdest,&readfds);

/* if(ifirst == -1) //Set all attribute when first start
{
status = ioctl(sPortdest,TCSETS,t);
ifirst = 1;
}*/


if(sPortdest!=-1)
{
cout<<"Open successfully\n";
do
{
testfds = readfds;

timeout.tv_sec=0;
timeout.tv_usec=1000;

r=select(FD_SETSIZE,&testfds,(fd_set *)0,(fd_set *)0,&timeout);

if(r == -1)
cout<<"Error in select";


//Activity happen on some ports
if(r > 0)
{
//check all

for(i=0;i<FD_SETSIZE;i++)
{

if(FD_ISSET(i,&testfds))
{
//Activity on serial port
if(i == sPortdest)
{


rbyte= read(sPortdest,recvbuf,1);

if(rbyte > 0)
{
recvbuf[1]='\0';
cout<<recvbuf;
count++;
if((count%11)==0)
{
cout<<"\n\t";
//c++;
cout<<c<<"\t";
cin>>inp_check;
// }
usleep(1000);
}
}
}
}
}

//Activity not happen on SP
if(r == 0)
{
//cout<<"\nwaiting\n";
write(sPortdest,"Test",4);
usleep(1000);

}

}while(1);
}
else
{
cout<<"Device could not be oepn successfully";
}


}

When writing communications code, start with some known methods for testing.

Rather than tear your hair out do the following....

1. ensure machines are connected, with null modem if required

2. run terminal emulator on those serial ports at both ends

3. confirm terminal emulators exchange characters

4. replace the send end with your sending program and check that the sender does send.

5. stop that, and restart the terminal emulator

6. stop the terminal emulator at the receiving end, start your receiving program

7. confirm receiving program receives what ever is typed.

hi...
but where to find terminal emulator....
what it is in the system????
I am using Fedora 6 .....
thanks

have you tried minicom?

but I didnt have minicom in my system..........
then can I test with any other tool.........
or from where I acn get minicom???//

I am trying with minicom....
but its status is showing offline..........
CTRL-A Z for help | 9600 8N1 | NOR | Minicom 2.1 | VT102 | Offline
this line is seen at the bottom of minicom...........
please help how to send and recieve data through minicom.......
thanks & regards,

Yes, mine says offline, I think it refers to successful modem dialup.