Hey all!
I am having difficulty reading from the serial port, it is being controlled by interrupts when the data comes in, it is supposed to be roughly 1Hz (depends on GPS signal and stuff)
I am encountering 2 problems:
1: Is that when i read using Interrupts so the serial port interrupts when the data is ready to be read, that happens roughly 1Hz, then after that i for some reason get like roughly 20(give or take) interrupts one after another which also reads the data (its not supposed to do this, because the program on the IMU that i am using outputs data roughly every 1Hz).
2: After i perform the read I noticed that the data in the serial port doesn;t get updated for some reason, and the data that is in the serial port is only maxed at 2048 bytes(anyone know why this is?), it only gets updated when i perform an InterruptWait() and corresponding InterruptUnmask() when this happens I found out that the data in the serial port gets refreshed 8 bytes at a time, so eventually after say 2048 - 167 *(amount of reads), the data in the serial port runs out and ruins my whole output.
To counteract that problem i put in a while loop (which is in the code below).
To make sure I only read when there is more then 167 bytes.
CODE: FOR READING FROM SERIAL PORT
while(1){
InterruptWait( 0, NULL );
//THE LOOP BELOW IS WHAT I USE TO MAKE SURE THERE IS MORE THEN 167 BYTES BEFORE I READ
while (tcischars(fd)<(167))
{
InterruptUnmask( IRQ, intr_id );
InterruptWait(0,NULL);
}
numRead = read(fd, buffer, SIZE_BUFFER);
printf("\n numREAD %d\n",numRead);
/WRITE/
printf("%s",buffer);
write(outfd,buffer,SIZE_BUFFER); //writing to file on PC/104
/* Reenable this interrupt since writing is finished */
InterruptUnmask( IRQ, intr_id );
}
CODE FOR SETTING UP SERIAL PORT
The IMU has to be read at 9600baud No flow contorl no parity and read 8 Bits at a time (ASCII)
int open_port(void)
{
int fd; /* File descriptor for the port */
struct termios termios_p; /termios structure/
fd = open("/dev/ser1", O_RDONLY | O_NOCTTY );
if (fd == -1)
{
perror("open_port: Unable to open /dev/ser1 - ");
return 0;
}
else
printf ("port opened\n");
tcgetattr(fd, &termios_p); /*read in the current settings*/
cfsetispeed(&termios_p, BAUD_RATE); //set input baud
cfsetospeed(&termios_p, BAUD_RATE); //set output baud
termios_p.c_cflag &= ~PARENB; //no parity bit (error checking bit)
termios_p.c_cflag &= ~CSIZE;
termios_p.c_cflag |= CS8; //set number of bits to 8
termios_p.c_cflag &=~ IHFLOW ; //disable input h/w flow control
termios_p.c_cflag &= ~OHFLOW ; //disable output h/w flow control
tcsetattr(fd, TCSANOW, &termios_p);
return (fd);
}
Can anyone please help me?
I am going crazy 
Thanks.
The IMU i am using the the PhoenixAX by O-Navi
Thanks so much for your help