UART 0x0D's becoming 0x0A's

Question

The following code configures two UART ports on a BeagleBone Black.

// Open the given file as read/write, don't become the controlling terminal, don't block
    int fileDescriptor = open(filename, O_RDWR | O_NOCTTY | O_SYNC);

    if(fileDescriptor == -1) {
        cerr << "open_port: Unable to open " << filename << " " << strerror(errno) << endl;
        return false;
    }

    struct termios tty;

    memset(&tty, 0, sizeof tty);

    if(tcgetattr(fileDescriptor, &tty) != 0) {
        cerr << strerror(errno) << endl;
        return false;
    }

    // Baud
    cfsetispeed(&tty, B115200);
    cfsetospeed(&tty, B115200);

    // 8-bit chars
    tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8;

    // Disable IGNBRK for mismatched speed tests; otherwise receive break
    // as \000 chars
    tty.c_iflag &= ~IGNBRK;         // disable break processing
    tty.c_lflag = 0;                // no signaling chars, no echo

    // No canonical processing
    tty.c_oflag = 0;                // no remapping, no delays
    tty.c_cc[VMIN]  = 0;            // read doesn't block
    tty.c_cc[VTIME] = 5;            // 0.5 seconds read timeout

    // Shut off xon/xoff ctrl
    tty.c_iflag &= ~(IXON | IXOFF | IXANY);

    // Ignore modem controls
    tty.c_cflag |= (CLOCAL | CREAD);

    // Enable reading
    tty.c_cflag &= ~(PARENB | PARODD);      // shut off parity
    tty.c_cflag |= 0;
    tty.c_cflag &= ~CSTOPB;
    tty.c_cflag &= ~CRTSCTS;

    if(tcsetattr(fileDescriptor, TCSANOW, &tty) != 0) {
        cerr << strerror(errno) << endl;
        return false;
    }

I'm able to send data, but for some reason 0x0D's sent are received as 0x0A's. I'm fairly sure something in this port configuration is doing this.

Answer 1

I notice these three flags on the man page for tcsetattr:

INLCR

Translate NL to CR on input.

IGNCR

Ignore carriage return on input.

ICRNL

Translate carriage return to newline on input (unless IGNCR is set).

You might want to try explicitly setting INLCR and ICRNL to 0 ?