regarding serial ports

Your problem could be that you don't test if read(..) == 0 and nothing has been read.

Could you show me the junk?

Rune Christensen Engineer

The OP is also outputting a string, but doesn't appear to be null terminating it first.

Note to OP: Don't forget to actually reserve one byte in the string for a null. In other words, only read a maximum of (buffer_size - 1) bytes at a time.

Simon.

hai if input is j,k,l then output: j =CE=83=8E=FFw
=98=F6=FF=BF=B1=84 =C0@0=B2=82=D4=F5=FF=BF
= =98=F6=FF=BF=B1=84 =C0@0=B2=98I
@
=F8S
@
I
@=D4=F5=FF=BF@=F6=FF=BFHH
@=CE=83 k =83=8E=FFw
@=CE=F6=FF=BF=B1=84 =C0@0=B2=98=82=D4=F5=FF=BF=CE=F6=FF=BF=B1= =84 =C0@0=B2=98I
@
S
@
=98I
@=F5=FF=BF@=F6=FF=BFHH
@=CE=F6=FF=BF=B1=84 =C0@0= =B2=83 l if if check for read=3D=3D0 also i didn't got any difference.

with regards

emb > > hai all,

I have looked at your code one more time.

When reading and writing you need to use two compatible functions.

if (fgets(buff, 10, fd) == NULL) { fprintf(stderr,"Read() failed!\n"); abort(); } fputs(buff, stdout);

another version is:

int len;

if ((len = read(fd, buff, 10)) < 0) { fprintf(stderr,"Read() failed!\n"); abort(); } write(stdout, buff, len);

Try one of them and tell me the result.

Rune Christensen Engineer

Here i have understood the idea,but the two versions which you has are giving warnings and not working too.

With Regards

emb in linux.

Could you be more specific with the warnings. Copy paste them and send them in a reply to this message.

What kind of output do you get now?

The transmitting part of your code you use both fgets(buff, sizeof(buff), stdin) and later while((c = fgetc(stdin)) != EOF) why that?

Rune Christensen Engineer

"i" is uninitialized and buff can only hold 10 characters. Plus in your fputc you are sending it a pointer as the 1st parameter instead of a int. You are lucky if this code even compiles or runs without crashing. If you can call that luck.

Hai all, its long time since i have mailed to this group(due to viral feaver).i got my serial port programming some what interactivelly.Here i am giving my send and receive codes to help others who may want to start work on serial ports.

/*sending program:*/

#include #include #include #include #include #include int main() { int fd,i,a,n=0; struct termios options; char buff[1]; fd=open("/dev/ttyS0",O_RDWR | O_NOCTTY); if(fd==-1) perror("Unable to open /dev/ttyS0\n"); else { while(1) { fcntl(fd,F_SETFL,0); tcgetattr(fd,&options); cfsetispeed(&options,B115200); cfsetospeed(&options,B115200); options.c_cflag |=(CLOCAL | CREAD); options.c_cflag &= ~PARENB; options.c_cflag &= ~CSTOPB; options.c_cflag &= ~CSIZE; options.c_cflag |=CS8; options.c_cflag |=(ICANON | ECHO | ECHOE); options.c_oflag |=OPOST; options.c_cc[VMIN]=1; options.c_cc[VTIME]=1; tcflush(fd,TCIFLUSH); tcsetattr(fd,TCSANOW,&options); i=fgetc(stdin); buff[0]=i; if(write(fd,buff,1)