using WiringPi library for serial communication on Raspberrypi the function serialPutchar(int fd, unsigned char c) and serialGetchar (int fd) works fine to send and receive integer value but does not show floating points
sender side
int main ()
{
int fd ;
int count ;
float val;
if ((fd = serialOpen ("/dev/ttyAMA0", 9600)) < 0)
{
fprintf (stderr, "Unable to open serial device: %s\n", strerror
(errno)) ;
return 1 ;
}
if (wiringPiSetup () == -1)
{
fprintf (stdout, "Unable to start wiringPi: %s\n", strerror
(errno)) ;
return 1 ;
}
for (count = 0 ; count < 256 ; ){
val=4.1;
fflush (stdout) ;
serialPutchar(fd,val);
++count ;
delay (500) ;
}
printf ("\n");
return 0;}
Receiver side
int main ()
{
int fd ;
if ((fd = serialOpen ("/dev/ttyUSB0", 9600)) < 0)
{
fprintf (stderr, "Unable to open serial device: %s\n", strerror
(errno)) ;
return 1 ;
}
if (wiringPiSetup () == -1)
{
fprintf (stdout, "Unable to start wiringPi: %s\n", strerror
(errno)) ;
return 1 ;
}
while(true)
{
printf ("%f", serialGetchar (fd)) ;
fflush (stdout) ;
printf ("\n") ;
}
return 0 ;
}
i expected the output to be 4.100000 but the actual output is 0.000000
Any help to send and receive floating point numbers will be appreciated Thanks in advance
What you need to do is break the float into bytes and then send/receive them one by one. Note: The following code assumes sender and receiver using same endian system.
//Sender
float f = 4.1;
int i = 0;
for (; i < sizeof(float); ++i)
serialPutchar(fd, ((char*)& f)[i]);
// receiver
float f;
int i = 0;
for (; i < sizeof(float); ++i)
((char*)& f)[i]) = serialGetchar(fd);