Hi All,
I have written two simple applications for reading
and writing from the serial port.The problem is when I
open /dev/ttyS1 and do read/write I cant read from the
device whereas when I open /dev/ttyS0 and do
read/write then I can very well read the full ten
bytes sent to the port while writing or sometimes I
even get only 1 or 2 bytes read from the port.
Now most important thing is, /dev/ttyS0 is used by
mouse in my PC and /dev/ttyS1 is the free serial port
to which I have attached a loopback.
So using the loopback I cant read, whereas using the
mouse port I am sometimes successfull in reading.
Please chech out the attached files and help me
out.Thanks in advance.
Cheers
Satya.
// Writing.c
#include "stdio.h"
#include "string.h"
#include "sys/types.h"
#include "unistd.h"
#include "fcntl.h"
#include "errno.h"
#define DEVICE "/dev/trial1"
int main()
{
int fd, iBytesWritten,i,j; /* file descriptor for
the device */
char buff[10]; /* string of 10 bytes */
if ((fd = open( DEVICE, O_WRONLY)) < 0 )
{
fprintf(stderr, "Can't open: ");
perror(DEVICE);
exit(1);
}
else
printf("/dev/trial1 opened with fd=%d \n", fd);
memset(buff,0,sizeof(buff));
strcpy(buff,"JAIMATADI");
buff[9]=0;
iBytesWritten = write(fd,buff,sizeof(buff));
printf("Number of bytes written %d\n",iBytesWritten);
for (j=0; j<10000000;j++)
continue;
if (iBytesWritten < 0)
printf("error number : %d \n", errno);
/* display the data written to the bufer */
printf(" buff is: %s \n", buff);
close(fd);
return;
}
-------------------------------------------------------
//Reading.c
#include "stdio.h"
#include "string.h"
#include "sys/types.h"
#include "unistd.h"
#include "fcntl.h"
#define DEVICE "/dev/trial1"
int main()
{
int fd; /* file descriptor for the device */
int i=0,iBytesread = 0;
char buff[10]; /* string of 10 bytes */
if ((fd = open( DEVICE, O_RDONLY)) < 0 )
{
fprintf(stderr, "Can't open: ");
perror(DEVICE);
exit(1);
}
else
printf("/dev/trial1 opened with fd=%d \n", fd);
memset(buff,0,sizeof(buff));
iBytesread = read(fd,buff,sizeof(buff));
if iBytesread == 0)
{
printf("%d bytes read\n",iBytesread);
exit (1);
}
else
{
/* display the data read into the bufer */
printf("%d bytes read\n ",iBytesread);
printf(" buff is: %s\n ", buff);
close(fd);
}
}
--------------------------------------------------------
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