beaglebone black debian uart example c programing

Question

I am running Embedded Linux. but right now I'm new. I want your help on something.

Debian distribution is installed in Beaglebone.

I want to make a uart communication. I am using the beagbone board P9-24 and P9-26 pins via uart1, but when I run the code it does not work.

I installed a ready-made TTL converter to the pins I gave above and I monitor the serial port through the hterm program. I set the baud rate to 9600. When I check my own TTL converter, it works, but when I connect it to the pins and run the program I wrote, I cannot see any output.

Would you help me with this topic?

The code I used is below.

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>
#include <string.h>

int open_uart(const char *port) {
    int uart_fd = open(port, O_RDWR | O_NOCTTY | O_NDELAY);
    if (uart_fd == -1) {
        perror("Error opening UART");
        return -1;
    }

    struct termios options;
    tcgetattr(uart_fd, &options);
    options.c_cflag = B9600 | CS8 | CLOCAL | CREAD;
    options.c_cflag &= ~PARENB;   // Parity disable
    options.c_cflag &= ~CSTOPB;   // 1 stop bit
    options.c_cflag &= ~CSIZE;
    options.c_cflag |= CS8;       // 8 data bits
    options.c_iflag = IGNPAR;
    options.c_oflag = 0;
    options.c_lflag = 0;
    tcflush(uart_fd, TCIFLUSH);
    tcsetattr(uart_fd, TCSANOW, &options);

    return uart_fd;
}

void send_data(int uart_fd, const char *data) {
    write(uart_fd, data, strlen(data));
}

int main() {
    const char *uart_port = "/dev/ttyS0"; // Bu portun doğru olup olmadığını kontrol et
    int uart_fd = open_uart(uart_port);

    if (uart_fd != -1) {
        printf("açıldı");
        const char *data_to_send = "Muhammed";
        send_data(uart_fd, data_to_send);
        close(uart_fd); // İşiniz bittiğinde portu kapatmayı unutmayın
    }

    return 0;
}