Hello!
I’m having an issue with using UART1 in c. I’ve shorted the TX and RX pins and I can echo back a series of two bytes I send from write. I’m using the non-canonical code given on this page. Everything works great the first two times I do this while running the program, but the third time the BBB hangs during the read command. Anyone have any idea what to do about this? Here’s the relevant parts of my code below,
void SERIAL_Init(void)
{
/*/
printf("\tSerial Port Initialization …");
SERIAL_fd = open(MODEMDEVICE,O_RDWR | O_NOCTTY /| O_NDELAY/);
if (SERIAL_fd < 0)
{ perror(MODEMDEVICE);
exit(-1);
}
fcntl(SERIAL_fd,F_SETFL,0);
tcgetattr(SERIAL_fd,&newtio);
newtio.c_cflag |= CS8 | CLOCAL | CREAD ;
cfsetispeed(&newtio,BAUDRATE);
cfsetospeed(&newtio,BAUDRATE);
newtio.c_iflag = IGNBRK | IGNPAR;
newtio.c_oflag = 0;
newtio.c_lflag = 0;
newtio.c_cc[VTIME]=0; / inter-character timer unused /
newtio.c_cc[VMIN]=31; / blocking read until 18 chars received /
tcflush(SERIAL_fd,TCIFLUSH);
tcsetattr(SERIAL_fd,TCSANOW,&newtio);
//
printf(“Done\n”);
return;
}
unsigned char test_data[2] = {0x00,0x00};
unsigned char read_command[2][2] = {
{0x1a,0x2b},
{0x90,0x05},
};
while(readTest == 0)
{
printf(“Enter 0 to read from maestro pin, 1 to continue with testing\n”);
scanf("%d",&readTest);
write(SERIAL_fd,read_command[0],2);
printf(“Wrote values…\n”);
num_bytes = read(SERIAL_fd,&test_data,2);
printf(“Value read: %x %x\n”,test_data[0],test_data[1]);
}